An Integrated, Low Temperature Process to Capture and Sequester Carbon Dioxide from Industrial Emissions

NASA Astrophysics Data System (ADS)

Wendlandt, R. F.; Foremski, J. J.

2013-12-01

Laboratory experiments show that it is possible to integrate (1) the chemistry of serpentine dissolution, (2) capture of CO2 gas from the combustion of natural gas and coal-fired power plants using aqueous amine-based solvents, (3) long-term CO2 sequestration via solid phase carbonate precipitation, and (4) capture solvent regeneration with acid recycling in a single, continuous process. In our process, magnesium is released from serpentine at 300°C via heat treatment with ammonium sulfate salts or at temperatures as low as 50°C via reaction with sulfuric acid. We have also demonstrated that various solid carbonate phases can be precipitated directly from aqueous amine-based (NH3, MEA, DMEA) CO2 capture solvent solutions at room temperature. Direct precipitation from the capture solvent enables regenerating CO2 capture solvent without the need for heat and without the need to compress the CO2 off gas. We propose that known low-temperature electrochemical methods can be integrated with this process to regenerate the aqueous amine capture solvent and recycle acid for dissolution of magnesium-bearing mineral feedstocks and magnesium release. Although the direct precipitation of magnesite at ambient conditions remains elusive, experimental results demonstrate that at temperatures ranging from 20°C to 60°C, either nesquehonite Mg(HCO3)(OH)●2H2O or a double salt with the formula [NH4]2Mg(CO3)2●4H2O or an amorphous magnesium carbonate precipitate directly from the capture solvent. These phases are less desirable for CO2 sequestration than magnesite because they potentially remove constituents (water, ammonia) from the reaction system, reducing the overall efficiency of the sequestration process. Accordingly, the integrated process can be accomplished with minimal energy consumption and loss of CO2 capture and acid solvents, and a net generation of 1 to 4 moles of H2O/6 moles of CO2 sequestered (depending on the solid carbonate precipitate and amount of produced H2 and O2 gas reacted to produce heat and water). Features of the integrated process include the following: 1) the four separate processes have compatible chemistry, enabling design of an integrated, continuous process scheme for CO2 capture and sequestration; 2) all 4 stages of the process can be conducted at ambient or slightly elevated temperatures; 3) precipitating carbonate directly from the capture solvent eliminates the need for costly CO2 gas compression; and 4) recycling the acid used for serpentine dissolution and the solvent used for CO2 capture reduces feed stock costs.

Structural elucidation, molecular representation and solvent interactions of vitrinite-rich and inertinite-rich South African coals

NASA Astrophysics Data System (ADS)

van Niekerk, Daniel

The structural differences and similarities of two Permian-aged South African coals, vitrinite-rich Waterberg and inertinite-rich Highveld coals (similar rank, carbon content and Permian age), were evaluated. With South African coals the opportunity presented itself to study not only Permian-aged Gondwana vitrinite but also inertinite. It was expected that these coals would differ from Northern hemisphere Carboniferous coals. It was concluded from various structural data that both coals, although different in maceral composition and depositional basins, are similar in their base structural composition. The main differences were that the inertinite-rich Highveld coal was more ordered, more aromatic, and had less hydrogen than the vitrinite-rich Waterberg coal. Analytical data were used to construct large-scale advanced molecular representations for vitrinite-rich Waterberg and inertinite-rich Highveld coals. The three-dimensional models were structurally diverse with a molecular weight range of 78 to 1900 amu. The vitrinite-rich coal model consisted of 18,572 atoms and 191 individual molecules and the inertinite-rich coal model consisted of 14,242 atoms and 158 individual molecules. This largescale modeling effort was enabled by the development of various PERL scripts to automate various visualization and analytical aspects. Coal swelling studies were conducted using the traditional pack-bed swelling method and a new novel single-particle stop-motion videography swelling method with NMP and CS2/NMP solvents. The pack-bed swelling showed that vitrinite-rich coal had a greater swelling extent and that swelling extent for both coals was greater in CS2/NMP binary solvent than for NMP. Single-particle swelling experiments showed that both coals, for both solvents, exhibit overshoot-type and climbing-type swelling behaviors. Inertinite-coal had a faster swelling rate, in both solvents, than the vitrinite-rich coal. The single-particle swelling data was used to calculate the kinetic parameters and it was found that the swelling was governed by relaxation of the coal structure (super-Case II swelling). X-ray computed tomography was conducted confirming anisotropic swelling. The petrographic transitions (maceral-group composition and reflectance) with solvent swelling and extraction were quantified. No changes in the maceral compositions were found, but changes in some coal particles were observed. Random reflectance analysis showed that, for both vitrinite and inertinite, there is a decrease in reflectance values with solvent treatment. Vitrinite reflectograms showed a shift from the dominant reflecting V-types to lower V-types. The inertinite reflectograms exhibited an increase in number of I-types (broadening of reflectrograms). Molecular simulation and visualization approaches to solvent swelling and extraction were performed on the proposed molecular models of vitrinite-rich and inertinite-rich coals. A theoretical extraction yield was determined using solubility parameters and showed agreement with experimental extraction yield trends. Statistical Associating Fluid Theory (SAFT) modeling was explored to test whether this method could predict swelling extent. The predicted swelling trends of SAFT were comparable to that of the experimental swelling results. SAFT was found to be a promising tool for solvent-coal interaction predictions. Partially solvent swollen structures were constructed by the addition of solvent molecules to the original coal molecules using a amorphous building approach. This method showed that coal-coal non-bonding interaction changed with the introduction of solvent. A disruption in the van der Waals interaction energies and a change in hydrogen bond distributions were observed in the swollen coal models and quantified. It was concluded that small changes in coal structure translates to significant changes in solvent interaction behavior. These changes were successfully visualized and simulated using atomistic molecular representations.

Role of Solvents in Improvement of Dissolution Rate of Drugs: Crystal Habit and Crystal Agglomeration

PubMed Central

Maghsoodi, Maryam

2015-01-01

Crystallization is often used for manufacturing drug substances. Advances of crystallization have achieved control over drug identity and purity, but control over the physical form remains poor. This review discusses the influence of solvents used in crystallization process on crystal habit and agglomeration of crystals with potential implication for dissolution. According to literature it has been known that habit modification of crystals by use of proper solvents may enhance the dissolution properties by changing the size, number and the nature of crystal faces exposed to the dissolution medium. Also, the faster dissolution rate of drug from the agglomerates of crystals compared with the single crystals may be related to porous structure of the agglomerates and consequently their better wettability. It is concluded from this review that in-depth understanding of role of the solvents in crystallization process can be applied to engineering of crystal habit or crystal agglomeration, and predictably dissolution improvement in poorly soluble drugs. PMID:25789214

Coal liquefaction process

DOEpatents

Skinner, Ronald W.; Tao, John C.; Znaimer, Samuel

1985-01-01

This invention relates to an improved process for the production of liquid carbonaceous fuels and solvents from carbonaceous solid fuels, especially coal. The claimed improved process includes the hydrocracking of the light SRC mixed with a suitable hydrocracker solvent. The recycle of the resulting hydrocracked product, after separation and distillation, is used to produce a solvent for the hydrocracking of the light solvent refined coal.

Enthalpy characteristics of the dissolution of L-valine in water/formamide mixtures at 298.15 K

NASA Astrophysics Data System (ADS)

Smirnov, V. I.; Badelin, V. G.

2016-11-01

The thermochemical dissolution of L-valine in solvent mixtures H2O + (formamide, N-methylformamide, and N, N-dimethylformamide) is studied at an organic component concentration of x 2 = 0-0.35 molar fractions and a temperature of 298.15 K. The experimental data are used to calculate standard enthalpies of dissolution, the transferring of L-valine from water to a mixed solvent, and the enthalpy coefficients of pairwise interactions ( h xy ) with organic solvent molecules. The correlation between the enthalpy characteristics of the dissolution of L-valine with the composition of aqueous organic mixtures and the nature of the organic solvent (its physicochemical properties) is determined. A comparative analysis of the values of h xy of a number of aliphatic L-amino acids in similar solvent mixtures with the hydrophobicity parameters of their side chains is performed.

Coal liquefaction process using pretreatment with a binary solvent mixture

DOEpatents

Miller, R.N.

1986-10-14

An improved process for thermal solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprises pretreating the coal with a binary mixture of an aromatic hydrocarbon and an aliphatic alcohol at a temperature below 300 C before the hydroliquefaction step. This treatment generally increases both conversion of coal and yields of oil. 1 fig.

Coal liquefaction process using pretreatment with a binary solvent mixture

DOEpatents

Miller, Robert N.

1986-01-01

An improved process for thermal solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprises pretreating the coal with a binary mixture of an aromatic hydrocarbon and an aliphatic alcohol at a temperature below 300.degree. C. before the hydroliquefaction step. This treatment generally increases both conversion of coal and yields of oil.

Investigating the structural transitions of proteins during dissolution by mass spectrometry.

PubMed

Gong, Xiaoyun; Xiong, Xingchuang; Qi, Lin; Fang, Xiang

2017-03-01

An appropriate solvent environment is essential for the implementation of biological functions of proteins. Interactions between protein residues and solvent molecules are of great importance for proteins to maintain their active structure and catalyze biochemical reactions. In this study, we investigated such interactions and studied the structural transitions of proteins during their dissolution process. Our previously developed technique, namely solvent assisted electric field induced desorption/ionization, was used for the dissolution and immediate ionization of proteins. Different solvents and proteins were involved in the investigation. According to the results, cytochrome c underwent significant unfolding during dissolution in the most commonly used NH 4 Ac buffer. The unfolding got more serious when the concentration of NH 4 Ac was further increased. Extending the dissolution time resulted in the re-folding of cytochrome c. In comparison, no unfolding was observed if cytochrome c was pre-dissolved in NH 4 Ac buffer and detected by nano-ESI. Furthermore, no unfolding was observed during the dissolution process of cytochrome c in water. Interactions between the residues of cytochrome c and the solute of NH 4 Ac might be the reason for the unfolding phenomenon. Similar unfolding phenomenon was observed on holo-myoglobin. However, the observed dissolution feature of insulin was different. No unfolding was observed on insulin during dissolution in NH 4 Ac buffers. Insulin underwent observable unfolding when water was used for dissolution. This might be due to the structural difference between different proteins. The obtained results in the present study furthered our insights into the interactions between proteins and the solvents during the phase transition of dissolution. Copyright © 2016 Elsevier B.V. All rights reserved.

Literature survey of properties of synfuels derived from coal

NASA Technical Reports Server (NTRS)

Reynolds, T. W.; Niedzwiecki, R. W.; Clark, J. S.

1980-01-01

A literature survey of the properties of synfuels for ground-based gas turbine applications is presented. Four major concepts for converting coal into liquid fuels are described: solvent extraction, catalytic liquefaction, pyrolysis, and indirect liquefaction. Data on full range syncrudes, various distillate cuts, and upgraded products are presented for fuels derived from various processes, including H-coal, synthoil, solvent-refined coal, donor solvent, zinc chloride hydrocracking, co-steam, and flash pyrolysis. Some typical ranges of data for coal-derived low Btu gases are also presented.

Literature survey of properties of synfuels derived from coal

NASA Technical Reports Server (NTRS)

Flores, F.

1982-01-01

A literature survey of the properties of synfuels for ground-based turbine applications is presented. The four major concepts for converting coal into liquid fuels (solvent extraction, catalytic liquefaction, pyrolysis, and indirect liquefaction), and the most important concepts for coal gasification (fixed bed, fluidized bed, entrained flow, and underground gasification) are described. Upgrading processes for coal derived liquid fuels are also described. Data presented for liquid fuels derived from various processes, including H-coal, synthoil, solvent refined coal, COED, donor solvent, zinc chloride hydrocracking, co-steam, and flash pyrolysis. Typical composition, and property data is also presented for low and medium-BTU gases derived from the various coal gasification processes.

Studies of the effect of selected nondonor solvents on coal liquefaction yields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jolley, R. L.; Rodgers, B. R.; Benjamin, B. M.

The objective of this research program was to evaluate the effectiveness of selected nondonor solvents (i.e., solvents that are not generally considered to have hydrogen available for hydrogenolysis reactions) for the solubilization of coals. Principal criteria for selection of candidate solvents were that the compound should be representative of a major chemical class, should be present in reasonable concentration in coal liquid products, and should have the potential to participate in hydrogen redistribution reactions. Naphthalene, phenanthrene, pyrene, carbazole, phenanthridine, quinoline, 1-naphthol, and diphenyl ether were evaluated to determine their effect on coal liquefaction yields and were compared with phenol andmore » two high-quality process solvents, Wilsonville SRC-I recycle solvent and Lummus ITSL heavy oil solvent. The high conversion efficacy of 1-naphthol may be attributed to its condensation to binaphthol and the consequent availability of hydrogen. The effectiveness of both the nitrogen heterocycles and the polycyclic aromatic hydrocarbon (PAH) compounds may be due to their polycyclic aromatic nature (i.e., possible hydrogen shuttling or transfer agents) and their physical solvent properties. The relative effectiveness for coal conversion of the Lummus ITSL heavy oil solvent as compared with the Wilsonville SRC-I process solvent may be attributed to the much higher concentration of 3-, 4-, and 5-ring PAH and hydroaromatic constituents in Lummus solvent. The chemistry of coal liquefaction and the development of recycle, hydrogen donor, and nondonor solvents are reviewed. The experimental methodology for tubing-bomb tests is outlined, and experimental problem areas are discussed.« less

Alcohols as hydrogen-donor solvents for treatment of coal

DOEpatents

Ross, David S.; Blessing, James E.

1981-01-01

A method for the hydroconversion of coal by solvent treatment at elevated temperatures and pressure wherein an alcohol having an .alpha.-hydrogen atom, particularly a secondary alcohol such as isopropanol, is utilized as a hydrogen donor solvent. In a particular embodiment, a base capable of providing a catalytically effective amount of the corresponding alcoholate anion under the solvent treatment conditions is added to catalyze the alcohol-coal reaction.

Molecular accessibility in solvent swelled coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kispert, L.D.

1991-08-01

Research continued on the determination of pore size and number distribution changes after swelling the coal samples with various solvents. A paper has just been submitted to the journal Fuel on the Low temperature Swelling of Argonne Premium Coal samples using solvents of varying polarity. The variation in the shape of the pore was followed as a function of temperature and swelling solvent polarity. This change in pore structure was attributed to break-up of the hydrogen bonding network in coal by polar solvents. The modification in pore shape from spherical to cylindrical was attributed to anisotropy in hydrogen bond densities.more » A copy of this paper has been attached to this report. Wojciech Sady has determine the structural changes in the pores that occur when APCS coal is dehydrated prior to swelling with polar solvents. These changes are different from those that occur in the absence of prior dehydration. He has also completed a study on the variation in the hydrogen bonding character of the pore wall as the coals are swelled with various polar solvents. A statistical analysis of the data is currently underway to determine important trends in his data. 9 refs.« less

Improved Supercritical-Solvent Extraction of Coal

NASA Technical Reports Server (NTRS)

Compton, L.

1982-01-01

Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

Supercritical multicomponent solvent coal extraction

NASA Technical Reports Server (NTRS)

Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (Inventor)

1983-01-01

The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

Process for solvent refining of coal using a denitrogenated and dephenolated solvent

DOEpatents

Garg, Diwakar; Givens, Edwin N.; Schweighardt, Frank K.

1984-01-01

A process is disclosed for the solvent refining of non-anthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.

Coal liquefaction in an inorganic-organic medium. [DOE patent application

DOEpatents

Vermeulen, T.; Grens, E.A. II; Holten, R.R.

Improved process for liquefaction of coal by contacting pulverized coal in an inorganic-organic medium solvent system containing a ZnCl/sub 2/ catalyst, a polar solvent with the structure RX where X is one of the elements O, N, S, or P, and R is hydrogen or a lower hydrocarbon radical; the solvent system can contain a hydrogen donor solvent (and must when RX is water) which is immiscible in the ZnCl/sub 2/ and is a hydroaromatic hydrocarbon selected from tetralin, dihydrophenanthrene, dihydroanthracene or a hydrogenated coal derived hydroaromatic hydrocarbon distillate fraction.

Integrated process for the solvent refining of coal

DOEpatents

Garg, Diwakar

1983-01-01

A process is set forth for the integrated liquefaction of coal by the catalytic solvent refining of a feed coal in a first stage to liquid and solid products and the catalytic hydrogenation of the solid product in a second stage to produce additional liquid product. A fresh inexpensive, throw-away catalyst is utilized in the second stage hydrogenation of the solid product and this catalyst is recovered and recycled for catalyst duty in the solvent refining stage without any activation steps performed on the used catalyst prior to its use in the solvent refining of feed coal.

Zinc sulfide liquefaction catalyst

DOEpatents

Garg, Diwakar

1984-01-01

A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

Progress in donor assisted coal liquefaction: Hydroaromatic compound formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kottenstette, R.J.; Stephens, H.P.

1993-12-31

The role of hydrogen donor compounds in coal liquefaction has been extensively investigated since the mid 1960`s using model compounds and process derived hydrogen donor solvents. Our recent research and that of other investigators have shown that two model compounds in particular have great efficacy in solvating low rank coals. 1,2,3,10b tetrahydrofluoranthene (H{sub 4}Fl) and 1,2,3,6,7,8 hexahydropyrene (H{sub 6}Py) have been used to dissolve Wyodak coal to > 95% soluble material as measured by tetrahydrofuran (THF). Although these hydrogen donors are very effective, they may not be found in any significant concentrations in actual liquefaction process recycle solvents. Therefore, studiesmore » with process derived recycle materials are necessary to understand donor solvent chemistry. The objective of this paper is to present results of solvent hydrogenation experiments using heavy distillate solvents produced during testing at the Wilsonville Advanced Coal Liquefaction Test Facility. We evaluated the impact of hydrogenation conditions upon hydrogen donor formation in process derived distillates and compared these process derived solvents with the highly effective H{sub 4}Fl and H{sub 6}Py donors in coal liquefaction tests. This paper presents data on reaction conditions used for distillate hydrotreating and subsequent coal liquefaction, with an aim toward understanding the relationship between reaction conditions and donor solvent quality in recycle distillates.« less

Enthalpy characteristics of L-proline dissolution in certain water-organic mixtures at 298.15 K

NASA Astrophysics Data System (ADS)

Badelin, V. G.; Smirnov, V. I.

2017-01-01

A thermochemical study of the processes of L-proline dissolution in aqueous solutions of acetonitrile, 1,4-dioxane, acetone, dimethyl sulfoxide, nitromethane and tetrahydrofuran at T = 298.15 K in the range of organic solvent concentrations x2 = 0-0.25 mole fractions is performed. Standard values of the enthalpies of solution and transfer of L-proline from water to mixed solvent, and the enthalpy coefficients of pairwise interactions between L-proline and molecules of organic solvents, are calculated. The effect the composition of a water-organic mixture and the structure of organic solvents have on the enthalpy characteristics of L-proline dissolution and transfer is examined. The effect the energy properties of intermolecular interactions between components of a mixed solvent has on the intermolecular interactions between L-proline and molecules of cosolvent is estimated. The correlation between the enthalpy characteristics of L-proline dissolution and electron-donor properties of organic cosolvent in aqueous solutions is determined.

Time phased alternate blending of feed coals for liquefaction

DOEpatents

Schweigharett, Frank; Hoover, David S.; Garg, Diwaker

1985-01-01

The present invention is directed to a method for reducing process performance excursions during feed coal or process solvent changeover in a coal hydroliquefaction process by blending of feedstocks or solvents over time. ,

Advanced liquefaction using coal swelling and catalyst dispersion techniques. Quarterly progress report, July--September 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, C.W.; Gutterman, C.; Chander, S.

The overall objective of this project is to develop a new approach for the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrates coal selection, pretreatment, coal swelling with catalyst impregnation, liquefaction, product recovery with characterization, alternate bottoms processing, and carrying out a technical assessment including an economic evaluation. The primary coal of this program, Black Thunder subbituminous coal, can be effectively beneficiated to about 3.5 wt % ash using aqueous sulfurous acid pretreatment. This treated coal can be further beneficiated to about 2 wt % ash usingmore » commercially available procedures. All three coals used in this study (Black Thunder, Burning Star bituminous, and Martin Lake lignite) are effectively swelled by a number of solvents. The most effective solvents are those having hetero-functionality. laboratory- and bench-scale liquefaction experimentation is underway using swelled and catalyst impregnated coal samples. Higher coal conversions were observed for the SO{sub 2}-treated subbituminous coal than the raw coal, regardless of catalyst type. Conversions of swelled coal were highest when Molyvan L, molybdenum naphthenate, and nickel octoate, respectively, were added to the liquefaction solvent. The study of bottoms processing consists of combining the ASCOT process which consists of coupling solvent deasphalting with delayed coking to maximize the production of coal-derived liquids while rejecting solids within the coke drum. The asphalt production phase has been completed; representative product has been evaluated. The solvent system for the deasphalting process has been established. Two ASCOT tests produced overall liquid yields (63.3 wt % and 61.5 wt %) that exceeded the combined liquid yields from the vacuum tower and ROSE process.« less

Firing of pulverized solvent refined coal

DOEpatents

Lennon, Dennis R.; Snedden, Richard B.; Foster, Edward P.; Bellas, George T.

1990-05-15

A burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired successfully without any performance limitations and without the coking of the solvent refined coal on the burner components. The burner is provided with a tangential inlet of primary air and pulverized fuel, a vaned diffusion swirler for the mixture of primary air and fuel, a center water-cooled conical diffuser shielding the incoming fuel from the heat radiation from the flame and deflecting the primary air and fuel steam into the secondary air, and a watercooled annulus located between the primary air and secondary air flows.

Modelling and shadowgraph imaging of cocrystal dissolution and assessment of in vitro antimicrobial activity for sulfadimidine/4-aminosalicylic acid cocrystals.

PubMed

Serrano, Dolores R; Persoons, Tim; D'Arcy, Deirdre M; Galiana, Carolina; Dea-Ayuela, Maria Auxiliadora; Healy, Anne Marie

2016-06-30

The aim of this work was to evaluate the influence of crystal habit on the dissolution and in vitro antibacterial and anitiprotozoal activity of sulfadimidine:4-aminosalicylic acid cocrystals. Cocrystals were produced via milling or solvent mediated processes. In vitro dissolution was carried out in the flow-through apparatus, with shadowgraph imaging and mechanistic mathematical models used to observe and simulate particle dissolution. In vitro activity was tested using agar diffusion assays. Cocrystallisation via milling produced small polyhedral crystals with antimicrobial activity significantly higher than sulfadimidine alone, consistent with a fast dissolution rate which was matched only by cocrystals which were milled following solvent evaporation. Cocrystallisation by solvent evaporation (ethanol, acetone) or spray drying produced flattened, plate-like or quasi-spherical cocrystals, respectively, with more hydrophobic surfaces and greater tendency to form aggregates in aqueous media, limiting both the dissolution rate and in vitro activity. Deviation from predicted dissolution profiles was attributable to aggregation behaviour, supported by observations from shadowgraph imaging. Aggregation behaviour during dissolution of cocrystals with different habits affected the dissolution rate, consistent with in vitro activity. Combining mechanistic models with shadowgraph imaging is a valuable approach for dissolution process analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Low-Cost Aqueous Coal Desulfurization

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Vasilakos, N.; Corcoran, W. H.; Grohmann, K.; Rohatgi, N. K.

1982-01-01

Water-based process for desulfurizing coal not only eliminates need for costly organic solvent but removes sulfur more effectively than an earlier solvent-based process. New process could provide low-cost commercial method for converting high-sulfur coal into environmentally acceptable fuel.

Dissolution of Used Nuclear Fuel Using a TBP/N-Paraffin Solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudisill, T. S.; Shehee, T. C.; Jones, D. H.

2017-10-02

The dissolution of unirradiated used nuclear fuel (UNF) pellets pretreated for tritium removal was demonstrated using a tributly phosphate (TBP) solvent. Dissolution of pretreated fuel in TBP could potentially combine dissolution with two cycle of solvent extraction required for separating the actinides and lanthanides from other fission products. Dissolutions were performed using UNF surrogates prepared from both uranyl nitrate and uranium trioxide produced from the pretreatment process by adding selected actinide and stable fission product elements. In laboratory-scale experiments, the U dissolution efficiency ranged from 80-99+% for both the nitrate and oxide surrogate fuels. On average, 80% of the Pumore » and 50% of the Np and Am in the nitrate surrogate dissolved; however, little of the transuranic elements dissolved in the oxide form. The majority of the 3+ lanthanide elements dissolved. Only small amounts of Sr (0-1.6%) and Mo (0.1-1.7%) and essentially no Cs, Ru, Zr, or Pd dissolved.« less

Method for improving dissolution efficiency in gas-absorption and liquid extraction processes. [Patent application

DOEpatents

Kanak, B.E.; Stephenson, M.J.

1980-01-11

A method is described for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacted undergoes transfer into the feed fluid to saturate the same. It has been found that such transfer significantly impairs dissolution efficiency. In accordance with the invention, an amount of the above-mentioned solvent is added to the feed fluid being introduced to the contact zone, the solvent being added in an amount sufficient to effect reduction or elimination of the above-mentioned transfer. Preferably, the solvent is added to the feed fluid in an amount saturating or supersaturating the feed fluid under the conditions prevailing in the contact zone.

Method for improving dissolution efficiency in gas-absorption and liquid extraction processes

DOEpatents

Kanak, Brant E.; Stephenson, Michael J.

1981-01-01

This invention is a method for improving dissolution efficiency in processes in which a feed fluid is introduced to a zone where it is contacted with a liquid solvent for preferentially removing a component of the feed and where part of the solvent so contacted undergoes transfer into the feed fluid to saturate the same. It has been found that such transfer significantly impairs dissolution efficiency. In accordance with the invention, an amount of the above-mentioned solvent is added to the feed fluid being introduced to the contact zone, the solvent being added in an amount sufficient to effect reduction or elimination of the above-mentioned transfer. Preferably, the solvent is added to the feed fluid in an amount saturating or supersaturating the feed fluid under the conditions prevailing in the contact zone.

EXXON donor solvent coal liquefaction process

NASA Technical Reports Server (NTRS)

Epperly, W. R.; Swabb, L. E., Jr.; Tauton, J. W.

1978-01-01

A solvent coal liquefaction process to produce low-sulfur liquid products from a wide range of coals is described. An integrated program of laboratory and engineering research and development in conjunction with operation of a 250 T/D pilot plant is discussed.

Two-stage coal liquefaction without gas-phase hydrogen

DOEpatents

Stephens, H.P.

1986-06-05

A process is provided for the production of a hydrogen-donor solvent useful in the liquefaction of coal, wherein the water-gas shift reaction is used to produce hydrogen while simultaneously hydrogenating a donor solvent. A process for the liquefaction of coal using said solvent is also provided. The process enables avoiding the use of a separate water-gas shift reactor as well as high pressure equipment for liquefaction. 3 tabs.

A comparative study of spray-dried and freeze-dried hydrocortisone/polyvinyl pyrrolidone solid dispersions.

PubMed

Dontireddy, Rakesh; Crean, Abina M

2011-10-01

Poor water solubility of new chemical entities (NCEs) is one of the major challenges the pharmaceutical industry currently faces. The purpose of this study was to investigate the feasibility of freeze-drying as an alternative technique to spray-drying to produce solid dispersions of poorly water-soluble drugs. Also investigated was the use of aqueous solvent mixtures in place of pure solvent for the production of solid dispersions. Aqueous solvent systems would reduce the environmental impact of pure organic solvent systems. Spray-dried and freeze-dried hydrocortisone/polyvinyl pyrrolidone solid dispersions exhibited differences in dissolution behavior. Freeze-dried dispersions exhibited faster dissolution rates than the corresponding spray-dried dispersions. Spray-dried systems prepared using both solvent systems (20% v/v and 96% v/v ethanol) displayed similar dissolution performance despite displaying differences in glass transition temperatures (T(g)) and surface areas. All dispersions showed drug/polymer interactions indicated by positive deviations in T(g) from the predicted values calculated using the Couchman-Karasz equation. Fourier transform infrared (FTIR) spectroscopic results confirmed the conversion of crystalline drug to the amorphous in the dispersions. Stability studies were preformed at 40°C and 75% relative humidity to investigate the physical stability of prepared dispersions. Recrystallization was observed after a month and the resultant dispersions were tested for their dissolution performance to compare with the dissolution performance of the dispersions prior to the stability study. The dissolution rate of the freeze-dried dispersions remained higher than both spray-dried dispersions after storage.

Supercritical-Multiple-Solvent Extraction From Coal

NASA Technical Reports Server (NTRS)

Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

1983-01-01

Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

Fired heater for coal liquefaction process

DOEpatents

Ying, David H. S.; McDermott, Wayne T.; Givens, Edwin N.

1985-01-01

A fired heater for a coal liquefaction process is operated under conditions to maximize the slurry slug frequency and thereby improve the heat transfer efficiency. The operating conditions controlled are (1) the pipe diameter and pipe arrangement, (2) the minimum coal/solvent slurry velocity, (3) the maximum gas superficial velocity, and (4) the range of the volumetric flow velocity ratio of gas to coal/solvent slurry.

Coal desulfurization process

NASA Technical Reports Server (NTRS)

Hsu, G. C.; Gavalas, G. R.; Ganguli, P. S.; Kalfayan, S. H.

1978-01-01

A method for chlorinolysis of coal is an organic solvent at a moderate temperautre and atmospheric pressure has been proven to be effective in removing sulfur, particularly the organic sulfur, from coal. Chlorine gas is bubbled through a slurry of moist coal in chlorinated solvent. The chlorinated coal is separated, hydrolyzed and the dechlorinated. Preliminary results of treating a high sulfutr (4.77%S) bituminous coal show that up to 70% organic sulfur, 90% hyritic sulfur and 76% total sulfur can be removed. The treated coal is dechlorinated by heating at 500 C. The presence of moisture helps to remove organic sulfur.

Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction. Final technical report, Volume 1 - effects of solvents, catalysts and temperature conditions on conversion and structural changes of low-rank coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Lili; Schobert, Harold H.; Song, Chunshan

1998-01-01

The main objectives of this project were to study the effects of low-temperature pretreatments on coal structure and their impacts on subsequent liquefaction. The effects of pretreatment temperatures, catalyst type, coal rank, and influence of solvent were examined. Specific objectives were to identify the basic changes in coal structure induced by catalytic and thermal pretreatments, and to determine the reactivity of the catalytically and thermally treated coals for liquefaction. In the original project management plan it was indicated that six coals would be used for the study. These were to include two each of bituminous, subbituminous, and lignite rank. Formore » convenience in executing the experimental work, two parallel efforts were conducted. The first involved the two lignites and one subbituminous coal; and the second, the two bituminous coals and the remaining subbituminous coal. This Volume presents the results of the first portion of the work, studies on two lignites and one subbituminous coal. The remaining work accomplished under this project will be described and discussed in Volume 2 of this report. The objective of this portion of the project was to determine and compare the effects of solvents, catalysts and reaction conditions on coal liquefaction. Specifically, the improvements of reaction conversion, product distribution, as well as the structural changes in the coals and coal-derived products were examined. This study targeted at promoting hydrogenation of the coal-derived radicals, generated during thermal cleavage of chemical bonds, by using a good hydrogen donor-solvent and an effective catalyst. Attempts were also made in efforts to match the formation and hydrogenation of the free radicals and thus to prevent retrogressive reaction.« less

Simultaneous destraction and desulfurization of Illinois coals with supercritical ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, B.C.

1983-01-01

Various Illinois coals (with Illinois number6 being the main one) are liquefied with various supercritical solvents (ethanol being the main solvent) at 543-598 K, system pressures of 6.99-24.23 MPa, flow rates of 3.0-7.5 ml/min, reaction time of 0-180 minutes, and coal particle sizes of 0.36-0.85 mm to 1.00-2.36 mm to systematically investigate the effects of flow rates, reaction time, coal particle size, temperature, pressure, coal characteristics (by using different Illinois coals), supercritical medium (by using different solvents), and the addition of potassium hydroxide. The % weight loss of coal and the % sulfur removal during destraction and desulfurization of coalmore » are functions of the flow rate, the reaction time, the coal particle size, temperature, pressure and the supercritical solvent. Temperature, pressure and the supercritical medium are the most important parameters in controlling the % weight loss of coal and the % sulfur removal. The % weight loss of coal can be related to a power law and fits quite nicely into a second order kinetic model. The % sulfur removal also follows a second order kinetic model. A secondary reaction is observed during the destraction process, which implies that destraction, and possibly desulfurization, of coal is a multistep reaction including a physical extraction step where the major portion of the coal and sulfur was removed and then followed by a chemical reaction. Supercritical ethanol definitely enhances the removal of sulfur compounds from coal. The enhanced selectivity by supercritical ethanol is greatest at a pressure just above the critical pressure of ethanol. Finally, addition of a base such as potassium hydroxide enhances both % weight loss of coal and the % sulfur removal.« less

Process for removal of hazardous air pollutants from coal

DOEpatents

Akers, David J.; Ekechukwu, Kenneth N.; Aluko, Mobolaji E.; Lebowitz, Howard E.

2000-01-01

An improved process for removing mercury and other trace elements from coal containing pyrite by forming a slurry of finely divided coal in a liquid solvent capable of forming ions or radicals having a tendency to react with constituents of pyrite or to attack the bond between pyrite and coal and/or to react with mercury to form mercury vapors, and heating the slurry in a closed container to a temperature of at least about 50.degree. C. to produce vapors of the solvent and withdrawing vapors including solvent and mercury-containing vapors from the closed container, then separating mercury from the vapors withdrawn.

Royal Society, Discussion on New Coal Chemistry, London, England, May 21, 22, 1980, Proceedings

NASA Astrophysics Data System (ADS)

1981-03-01

A discussion of new coal chemistry is presented. The chemical and physical structure of coal is examined in the first section, including structural studies of coal extracts, metal and metal complexes in coal and coal microporosity. The second section presents new advances in applied coal technology. The development of liquid fuels and chemicals from coal is given especial emphasis, with papers on the Sasol Synthol process, the Shell-Koppers gasification process, liquefaction and gasification in Germany, the Solvent Refined Coal process, the Exxon Donor Solvent liquefaction process and the Mobil Methanol-to-Gasoline process. Finally, some developments that will be part of the future of coal chemistry in the year 2000 are examined in the third section, including coal-based chemical complexes and the use of coal as an alternative source to oil for chemical feedstocks.

The Leaching of Aluminium In Spanish Clays, Coal Mining Wastes and Coal Fly Ashes by Sulphuric Acid.

NASA Astrophysics Data System (ADS)

Fernández, A. M.; Ibáñez, J. L.; Llavona, M. A.; Zapico, R.

The acid leaching of aluminium from several non traditional ores, bayerite, kaolinite, different clays, coal mining wastes and coal fly ashes, and the kinetic of their dissolution are described. The effects of time, temperature, acid concentration, sample calcination, particle size were examined. The leaching of aluminium is dependent on acid concentration and strongly on temperature. Generally, the time to reach a fixed percentage of dissolution decreases with increasing acid concentration in the range 6% to 40% acid by weight. On clays and coal mining wastes a good relation between Al removal and ratio kaolinite/illite was also observed at all temperatures and acid concentration tested. Coal fly ashes are particles that were heated at very high temperatures in the power station and Al compounds were transformed into mullite and so Al recovery was minor. Several rate equations describing the kinetics of the leach reaction were discussed and Kinetic parameters and activation energy values of samples are presented.

Fundamental Insights into the Dissolution and Precipitation of Cellulosic Biomass from Ionic Liquid Mixtures

NASA Astrophysics Data System (ADS)

Minnick, David L.

Lignocellulose is the most abundant biopolymer on earth making it a promising feedstock for the production of renewable chemicals and fuels. However, utilization of biomass remains a challenge as recalcitrance of cellulose and hemicellulose hinder separation and conversion of these carbohydrates. For instance, the complex inter- and intra- molecular hydrogen bonding network of cellulose renders it insoluble in nearly all aqueous and organic solvents. Alternatively, select ionic liquids (ILs) dissolve significant quantities. Through an ionic liquid mediated dissolution and precipitation process cellulose crystallinity is significantly reduced consequently enhancing subsequent chemical and biochemical reaction processes. Therefore, understanding the thermodynamics of ionic liquid - cellulose mixtures is imperative to developing an IL based biomass processing system. This dissertation illustrates solid-liquid phase equilibrium results for the dissolution and precipitation of cellulose in various IL/cosolvent, IL/antisolvent, and IL/mixed solvent systems with the ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIm][DEP]). Molecular interactions between the ionic liquid, organic solvents, and cellulose are assessed by spectroscopic techniques including Kamlet-Taft solvatochromic analysis, FTIR, and NMR. Additionally, this dissertation discusses how preferential solvation of the IL cation and anion by co- and anti-solvents impact the ability of IL ions to interact with cellulose thus affecting the cellulose dissolution capacity of the various IL-solvent mixtures.

Research on solvent-refined coal. Quarterly technical progress report, July 1-September 30, 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-07-01

This report describes progress on the Research on Solvent Refined Coal project by The Pittsburg and Midway Coal Mining Company's Merriam Laboratory during the third quarter of 1981. A four-part experiment was conducted with subbituminous Edna coal, pyrite and/or bituminous Ireland coal at 457/sup 0/C and 1800 psig or 450/sup 0/C and 2250 psig. The purpose was to determine the conditions appropriate for processing a 50/50 by weight blend of these coals. A total of four runs (11 experiments) discussed this quarter were directed toward the study of disposable catalysts. Subbituminous coals from the Edna and Belle Ayr Mines weremore » processed in the SRC II mode. Additives investigated were pyrite, ferric oxide, molybdenum doped ferric oxide and iron dispersed on silica-alumina. The level and type of sulfur added in conjunction with ferric oxide catalysts was also explored as well as addition of sulfur by itself. Two solvent hydrogenation runs and five SRC I runs were directed toward a preliminary investigation of short residence time processing of western (Belle Ayr) coals.« less

Hydrogenation of coal liquid utilizing a metal carbonyl catalyst

DOEpatents

Feder, Harold M.; Rathke, Jerome W.

1979-01-01

Coal liquid having a dissolved transition metal, catalyst as a carbonyl complex such as Co.sub.2 (CO.sub.8) is hydrogenated with hydrogen gas or a hydrogen donor. A dissociating solvent contacts the coal liquid during hydrogenation to form an immiscible liquid mixture at a high carbon monoxide pressure. The dissociating solvent, e.g. ethylene glycol, is of moderate coordinating ability, while sufficiently polar to solvate the transition metal as a complex cation along with a transition metal, carbonyl anion in solution at a decreased carbon monoxide pressure. The carbon monoxide pressure is reduced and the liquids are separated to recover the hydrogenated coal liquid as product. The dissociating solvent with the catalyst in ionized form is recycled to the hydrogenation step at the elevated carbon monoxide pressure for reforming the catalyst complex within fresh coal liquid.

Study of the solubility and stability of polystyrene wastes in a dissolution recycling process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia, Maria Teresa; Gracia, Ignacio; Duque, Gema

2009-06-15

Dissolution with suitable solvents is one of the cheapest and more efficient processes for polystyrene waste management. In this work the solubility of polystyrene foams in several solvents benzene, toluene, xylene, tetrahydrofuran, chloroform, 1,3-butanediol, 2-butanol, linalool, geraniol, d-limonene, p-cymene, terpinene, phellandrene, terpineol, menthol, eucalyptol, cinnamaldheyde, nitrobenzene, N,N-dimethylformamide and water has been determined. Experimental results have shown that to develop a 'green process' the constituents of essential oils, d-limonene, p-cymene, terpinene, phellandrene, are the most appropriate solvents. The action of these solvent does not produce any degradation of polymer chains. The solubility of the polymer in the mentioned solvents at differentmore » temperatures has been investigated. The solvent can be easily recycled by distillation.« less

Can crystal engineering be as beneficial as micronisation and overcome its pitfalls?: A case study with cilostazol.

PubMed

Sai Gouthami, Kodukula; Kumar, Dinesh; Thipparaboina, Rajesh; Chavan, Rahul B; Shastri, Nalini R

2015-08-01

Improvement in dissolution of the drugs having poor solubility is a challenge in pharmaceutical industry. Micronization is one technique, employed for dissolution enhancement of cilostazol, a BCS class II drug. However, the obtained micronized drug possesses poor flowability. The aim of this study was to improve the dissolution rate and flow properties of cilostazol by crystal engineering, using habit modification method and compare with micronized cilostazol bulk drug. Simulation studies were performed to predict the effect of solvents on cilostazol crystal habit. Cilostazol crystals with different habits were prepared by solvent:anti-solvent crystallization technique. SEM, FTIR, DSC, TGA and PXRD were used for solid state characterization. The results revealed that cilostazol re-crystallized from methanol-hexane system were hexagonal and ethanol-hexane system gave rods. Cilostazol engineered habits showed increased dissolution rate than unprocessed drug but similar dissolution rate when compared to micronized cilostazol. Micronized cilostazol showed a dissolution efficiency of 75.58% where as cilostazol recrystallized from methanol-hexane and ethanol-hexane systems resulted in a dissolution efficiency of 72.63% and 68.63%, respectively. In addition, crystal engineering resulted in improved flow properties of re-crystallized habits when compared to micronized form of the drug. In conclusion, crystal engineering by habit modification show potential for dissolution enhancement with an added advantage of improved flow properties over micronization technique, for poorly soluble drugs like cilostazol. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing the Impact of Removing Select Materials from Coal Mine Overburden, Central Appalachia Region, USA

EPA Science Inventory

The exposure of readily soluble components of overburden materials from surface coal mining to air and water results in mineral oxidation and carbonate mineral dissolution, thus increasing coal mine water conductivity. A conductivity benchmark of 300 µS/cm for mine water dischar...

Method for controlling boiling point distribution of coal liquefaction oil product

DOEpatents

Anderson, R.P.; Schmalzer, D.K.; Wright, C.H.

1982-12-21

The relative ratio of heavy distillate to light distillate produced in a coal liquefaction process is continuously controlled by automatically and continuously controlling the ratio of heavy distillate to light distillate in a liquid solvent used to form the feed slurry to the coal liquefaction zone, and varying the weight ratio of heavy distillate to light distillate in the liquid solvent inversely with respect to the desired weight ratio of heavy distillate to light distillate in the distillate fuel oil product. The concentration of light distillate and heavy distillate in the liquid solvent is controlled by recycling predetermined amounts of light distillate and heavy distillate for admixture with feed coal to the process in accordance with the foregoing relationships. 3 figs.

Method for controlling boiling point distribution of coal liquefaction oil product

DOEpatents

Anderson, Raymond P.; Schmalzer, David K.; Wright, Charles H.

1982-12-21

The relative ratio of heavy distillate to light distillate produced in a coal liquefaction process is continuously controlled by automatically and continuously controlling the ratio of heavy distillate to light distillate in a liquid solvent used to form the feed slurry to the coal liquefaction zone, and varying the weight ratio of heavy distillate to light distillate in the liquid solvent inversely with respect to the desired weight ratio of heavy distillate to light distillate in the distillate fuel oil product. The concentration of light distillate and heavy distillate in the liquid solvent is controlled by recycling predetermined amounts of light distillate and heavy distillate for admixture with feed coal to the process in accordance with the foregoing relationships.

Initial dissolution kinetics of cocrystal of carbamazepine with nicotinamide.

PubMed

Hattori, Yusuke; Sato, Maiko; Otsuka, Makoto

2015-11-01

Objectives of this study are investigating the initial dissolution kinetics of the cocrystal of carbamazepine (CBZ) with nicotinamide (NIC) and understanding its initial dissolution process. Cocrystal solids of CBZ with NIC were prepared by co-milling and solvent evaporation methods. The formation of cocrystal solid was verified via X-ray diffraction measurement. Dissolution tests of the solids were performed using an original flow cell and ultraviolet-visible spectroscopic detector. The spectra monitored in situ were analyzed to determine the dissolved compounds separately using the classical least squares regression method. The initial dissolution profiles were interpreted using simultaneous model of dissolution and phase changes. In the initial dissolution, CBZ in the cocrystal structure dissolved in water and it was suggested that CBZ reached a metastable intermediate state simultaneously with dissolution. The cocrystal solid prepared by solvent evaporation provided a higher rate constant of the phase change than that prepared by co-milling. Our results thus support the use of evaporation as the method of choice to produce ordered cocrystal structures. We suggest that CBZ forms dihydrate during the dissolution process; however, during the initial phase of dissolution, CBZ changes to a metastable intermediate phase. © 2015 Royal Pharmaceutical Society.

Spectroscopic investigation confirms retaining the pristine nature of single-walled carbon nanotubes on dissolution in aniline

NASA Astrophysics Data System (ADS)

Singha, Somdutta; Ghosh, Swapankumar

2017-09-01

Carbon nanotubes in all forms are very much insoluble in both organic and inorganic solvents due to its high agglomeration and entangled morphology. General methods for dissolution of single-walled carbon nanotubes (SWNTs) are mostly associated with complexation or polymerization or addition of macromolecules which change the physical or chemical properties of SWNTs and the pristine nature of SWNTs is lost. Dissolution of SWNTs in a solvent like aniline is practiced here which is a very simple reaction method. Here aniline is capable to form a SWNT-aniline charge transfer complex without attachment of macromolecules or polymer which is also soluble in other organic solvents. Solvation of SWNTs by this method is also capable of maintaining the similarity between the structure of SWNTs before and after the dissolution, which means that the pristine nature of SWNTs is preserved. Formation of charge transfer complex in this reaction has been proven by UV-Vis/NIR absorption and photoluminescence spectroscopy. Raman spectroscopy and electron microscopy (FESEM and TEM) are the evidences for protection of the pristine nature of SWNTs even after high-temperature complexation reaction with aniline and also after solubilization in organic solvents.

Antisolvent crystallization of a cardiotonic drug in ionic liquids: Effect of mixing on the crystal properties

NASA Astrophysics Data System (ADS)

de Azevedo Jacqueline, Resende; Fabienne, Espitalier; Jean-Jacques, Letourneau; Inês, Ré Maria

2017-08-01

LASSBio-294 (3,4-methylenedioxybenzoyl-2-thienylhydrazon) is a poorly soluble drug which has been proposed to have major advantages over other cardiotonic drugs. Poorly water soluble drugs present limited bioavailability due to their low solubility and dissolution rate. An antisolvent crystallization processing can improve the dissolution rate by decreasing the crystals particle size. However, LASSBio-294 is also poorly soluble in organic solvents and this operation is limited. In order to open new perspectives to improve dissolution rate, this work has investigated LASSBio-294 in terms of its antisolvent crystallization in 1-ethyl-3-methylimidazolium methyl phosphonate [emim][CH3O(H)PO2] as solvent and water as antisolvent. Two modes of mixing are tested in stirred vessel with different pre-mixers (Roughton or T-mixers) in order to investigate the mixing effect on the crystal properties (crystalline structure, particle size distribution, residual solvent and in vitro dissolution rate). Smaller drug particles with unchanged crystalline structure were obtained. Despite the decrease of the elementary particles size, the recrystallized particles did not achieve a better dissolution profile. However, this study was able to highlight a certain number of findings such as the impact of the hydrodynamic conditions on the crystals formation and the presence of a gel phase limiting the dissolution rate.

Solvent recyclability in a multistep direct liquefaction process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hetland, M.D.; Rindt, J.R.

1995-12-31

Direct liquefaction research at the Energy & Environmental Research Center (EERC) has, for a number of years, concentrated on developing a direct liquefaction process specifically for low-rank coals (LRCs) through the use of hydrogen-donating solvents and solvents similar to coal-derived liquids, the water/gas shift reaction, and lower-severity reaction conditions. The underlying assumption of all of the research was that advantage could be taken of the reactivity and specific qualities of LRCs to produce a tetrahydrofuran (THF)-soluble material that might be easier to upgrade than the soluble residuum produced during direct liquefaction of high-rank coals. A multistep approach was taken tomore » produce the THF-soluble material, consisting of (1) preconversion treatment to prepare the coal for solubilization, (2) solubilization of the coal in the solvent, and (3) polishing to complete solubilization of the remaining material. The product of these three steps can then be upgraded during a traditional hydrotreatment step. The results of the EERC`s research indicated that additional studies to develop this process more fully were justified. Two areas were targeted for further research: (1) determination of the recyclability of the solvent used during solubilization and (2) determination of the minimum severity required for hydrotreatment of the liquid product. The current project was funded to investigate these two areas.« less

Competitive interactions and controlled release of a natural antioxidant from halloysite nanotubes.

PubMed

Hári, József; Gyürki, Ádám; Sárközi, Márk; Földes, Enikő; Pukánszky, Béla

2016-01-15

Halloysite nanotubes used as potential carrier material for a controlled release stabilizer in polyethylene were thoroughly characterized with several techniques including the measurement of specific surface area, pore volume and surface energy. The high surface energy of the halloysite results in the strong bonding of the additive to the surface. Dissolution experiments carried out with eight different solvents for the determination of the effect of solvent characteristics on the amount of irreversibly bonded quercetin proved that adsorption and dissolution depend on competitive interactions prevailing in the system. Solvents with low polarity dissolve only surplus quercetin adsorbed in multilayers. Polyethylene is a very apolar polymer forming weak interactions with every substance; quercetin dissolves into it from the halloysite surface only above a critical surface coverage. Stabilization experiments confirmed that strong adhesion prevents dissolution and results in limited stabilization efficiency. At larger adsorbed amounts better stability and extended effect were measured indicating dissolution and controlled release. Copyright © 2015 Elsevier Inc. All rights reserved.

Coal liquefaction and hydrogenation

DOEpatents

Schindler, Harvey D.; Chen, James M.

1985-01-01

Disclosed is a coal liquefaction process using two stages. The first stage liquefies the coal and maximizes the product while the second stage hydrocracks the remainder of the coal liquid to produce solvent.

Testing of advanced liquefaction concepts in HTI Run ALC-1: Coal cleaning and recycle solvent treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robbins, G.A.; Winschel, R.A.; Burke, F.P.

In 1991, the Department of Energy initiated the Advanced Liquefaction Concepts Program to promote the development of new and emerging technology that has potential to reduce the cost of producing liquid fuels by direct coal liquefaction. Laboratory research performed by researchers at CAER, CONSOL, Sandia, and LDP Associates in Phase I is being developed further and tested at the bench scale at HTI. HTI Run ALC-1, conducted in the spring of 1996, was the first of four planned tests. In Run ALC-1, feed coal ash reduction (coal cleaning) by oil agglomeration, and recycle solvent quality improvement through dewaxing and hydrotreatmentmore » of the recycle distillate were evaluated. HTI`s bench liquefaction Run ALC-1 consisted of 25 days of operation. Major accomplishments were: 1) oil agglomeration reduced the ash content of Black Thunder Mine coal by 40%, from 5.5% to 3.3%; 2) excellent coal conversion of 98% was obtained with oil agglomerated coal, about 3% higher than the raw Black Thunder Mine coal, increasing the potential product yield by 2-3% on an MAF coal basis; 3) agglomerates were liquefied with no handling problems; 4) fresh catalyst make-up rate was decreased by 30%, with no apparent detrimental operating characteristics, both when agglomerates were fed and when raw coal was fed (with solvent dewaxing and hydrotreating); 5) recycle solvent treatment by dewaxing and hydrotreating was demonstrated, but steady-state operation was not achieved; and 6) there was some success in achieving extinction recycle of the heaviest liquid products. Performance data have not been finalized; they will be available for full evaluation in the new future.« less

Coal Liquefaction desulfurization process

DOEpatents

Givens, Edwin N.

1983-01-01

In a solvent refined coal liquefaction process, more effective desulfurization of the high boiling point components is effected by first stripping the solvent-coal reacted slurry of lower boiling point components, particularly including hydrogen sulfide and low molecular weight sulfur compounds, and then reacting the slurry with a solid sulfur getter material, such as iron. The sulfur getter compound, with reacted sulfur included, is then removed with other solids in the slurry.

Characterization of nonderivatized plant cell walls using high-resolution solution-state NMR spectroscopy

Treesearch

Daniel J. Yelle; John Ralph; Charles R. Frihart

2008-01-01

A recently described plant cell wall dissolution system has been modified to use perdeuterated solvents to allow direct in-NMR-tube dissolution and high-resolution solution-state NMR of the whole cell wall without derivatization. Finely ground cell wall material dissolves in a solvent system containing dimethylsulfoxide-d6 and 1-methylimidazole-d6 in a ratio of 4:1 (v/...

Spin-mapping of Coal Structures with ESE and ENDOR

DOE R&D Accomplishments Database

Belford, R. L.; Clarkson, R. B.

1989-12-01

The broad goals of this project are to determine by nondestructive magnetic resonance methods chemical and physical structural characteristics of organic parts of native and treated coals. In this project period, we have begun to explore a technique which promises to enable us to follow to course of coal cleaning processes with microscopic spatial resolution. For the past five years, our laboratory has worked on extensions of the EPR technique as applied to coal to address these analytical problems. In this report we (1) describe the world's first nuclear magnetic resonance imaging results from an Illinois {number sign}6 coal and (2) transmit a manuscript describing how organic sulfur affect the very-high-frequency EPR spectra of coals. Magnetic resonance imaging (MRI) is a non-destructive technique that has found wide medical application as a means of visualizing the interior of human bodies. We have used MRI techniques to study the diffusion of an organic solvent (DMSO) into the pores of Illinois {number sign}6 coal. Proton MRI images reveal that this solvent at room temperature does not penetrate approximately 30% of the coal volume. Regions of the coal that exclude solvent could be related to inertinite and mineral components. A multi-technique imaging program is contemplated.

AIR EMISSIONS FROM COMBUSTION OF SOLVENT REFINED COAL

EPA Science Inventory

The report gives details of a Solvent Refined Coal (SRC) combustion test at Georgia Power Company's Plant Mitchell, March, May, and June 1977. Flue gas samples were collected for modified EPA Level 1 analysis; analytical results are reported. Air emissions from the combustion of ...

Catalysts for coal liquefaction processes

DOEpatents

Garg, Diwakar

1986-01-01

Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

Catalysts for coal liquefaction processes

DOEpatents

Garg, D.

1986-10-14

Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

Short residence time coal liquefaction process including catalytic hydrogenation

DOEpatents

Anderson, R.P.; Schmalzer, D.K.; Wright, C.H.

1982-05-18

Normally solid dissolved coal product and a distillate liquid product are produced by continuously passing a feed slurry comprising raw feed coal and a recycle solvent oil and/or slurry together with hydrogen to a preheating-reaction zone, the hydrogen pressure in the preheating-reaction zone being at least 1,500 psig (105 kg/cm[sup 2]), reacting the slurry in the preheating-reaction zone at a temperature in the range of between about 455 and about 500 C to dissolve the coal to form normally liquid coal and normally solid dissolved coal. A total slurry residence time is maintained in the reaction zone ranging from a finite value from about 0 to about 0.2 hour, and reaction effluent is continuously and directly contacted with a quenching fluid to substantially immediately reduce the temperature of the reaction effluent to below 425 C to substantially inhibit polymerization so that the yield of insoluble organic matter comprises less than 9 weight percent of said feed coal on a moisture-free basis. The reaction is performed under conditions of temperature, hydrogen pressure and residence time such that the quantity of distillate liquid boiling within the range C[sub 5]-454 C is an amount at least equal to that obtainable by performing the process under the same condition except for a longer total slurry residence time, e.g., 0.3 hour. Solvent boiling range liquid is separated from the reaction effluent and recycled as process solvent. The amount of solvent boiling range liquid is sufficient to provide at least 80 weight percent of that required to maintain the process in overall solvent balance. 6 figs.

Short residence time coal liquefaction process including catalytic hydrogenation

DOEpatents

Anderson, Raymond P.; Schmalzer, David K.; Wright, Charles H.

1982-05-18

Normally solid dissolved coal product and a distillate liquid product are produced by continuously passing a feed slurry comprising raw feed coal and a recycle solvent oil and/or slurry together with hydrogen to a preheating-reaction zone (26, alone, or 26 together with 42), the hydrogen pressure in the preheating-reaction zone being at least 1500 psig (105 kg/cm.sup.2), reacting the slurry in the preheating-reaction zone (26, or 26 with 42) at a temperature in the range of between about 455.degree. and about 500.degree. C. to dissolve the coal to form normally liquid coal and normally solid dissolved coal. A total slurry residence time is maintained in the reaction zone ranging from a finite value from about 0 to about 0.2 hour, and reaction effluent is continuously and directly contacted with a quenching fluid (40, 68) to substantially immediately reduce the temperature of the reaction effluent to below 425.degree. C. to substantially inhibit polymerization so that the yield of insoluble organic matter comprises less than 9 weight percent of said feed coal on a moisture-free basis. The reaction is performed under conditions of temperature, hydrogen pressure and residence time such that the quantity of distillate liquid boiling within the range C.sub.5 -454.degree. C. is an amount at least equal to that obtainable by performing the process under the same condition except for a longer total slurry residence time, e.g., 0.3 hour. Solvent boiling range liquid is separated from the reaction effluent (83) and recycled as process solvent (16). The amount of solvent boiling range liquid is sufficient to provide at least 80 weight percent of that required to maintain the process in overall solvent balance.

Iron catalyzed coal liquefaction process

DOEpatents

Garg, Diwakar; Givens, Edwin N.

1983-01-01

A process is described for the solvent refining of coal into a gas product, a liquid product and a normally solid dissolved product. Particulate coal and a unique co-catalyst system are suspended in a coal solvent and processed in a coal liquefaction reactor, preferably an ebullated bed reactor. The co-catalyst system comprises a combination of a stoichiometric excess of iron oxide and pyrite which reduce predominantly to active iron sulfide catalysts in the reaction zone. This catalyst system results in increased catalytic activity with attendant improved coal conversion and enhanced oil product distribution as well as reduced sulfide effluent. Iron oxide is used in a stoichiometric excess of that required to react with sulfur indigenous to the feed coal and that produced during reduction of the pyrite catalyst to iron sulfide.

Effects of carbonization and solvent-extraction on change in fuel characteristics of sewage sludge.

PubMed

Park, Sang-Woo; Jang, Cheol-Hyeon

2011-09-01

Urban sewage sludge was carbonized at 300-500°C for 1h, and combustible components were extracted through the solvent-extraction process. N-methyl-2-pyrrolidinone (NMP) was used as the solvent for extraction, and the extraction temperature was fixed at 360°C. The atomic ratios of the solvent-extracted sludge of CS300 (ECS300) were shown to be 1.04 for H/C and 0.11 for O/C, which represented the characteristics of its coal band. Thus, its coal band was similar to that of a high-rank fuel such as bituminous coal. FT-IR analysis showed that the absorbance band of ECS300 was considerably different from that of dried sludge (RS) or the carbonized sludge at 300°C (CS300) but similar to that of coal, although the ash content absorbance band of 800-1200 cm(-1) was of very low intensity. The combustion profile showed that combustion of ESC300 occurred at a temperature higher than the ignition temperature (T(i)) or maximum weight loss rate (DTG(max)) of coal. Copyright © 2011 Elsevier Ltd. All rights reserved.

Coal liquefaction process

DOEpatents

Maa, Peter S.

1978-01-01

A process for liquefying a particulate coal feed to produce useful petroleum-like liquid products which comprises contacting; in a series of two or more coal liquefaction zones, or stages, graded with respect to temperature, an admixture of a polar compound; or compounds, a hydrogen donor solvent and particulate coal, the total effluent being passed in each instance from a low temperature zone, or stage to the next succeeding higher temperature zone, or stage, of the series. The temperature within the initial zone, or stage, of the series is maintained about 70.degree. F and 750.degree. F and the temperature within the final zone, or stage, is maintained between about 750.degree. F and 950.degree. F. The residence time within the first zone, or stage, ranges, generally, from about 20 to about 150 minutes and residence time within each of the remaining zones, or stages, of the series ranges, generally, from about 10 minutes to about 70 minutes. Further steps of the process include: separating the product from the liquefaction zone into fractions inclusive of a liquid solvent fraction; hydrotreating said liquid solvent fraction in a hydrogenation zone; and recycling the hydrogenated liquid solvent mixture to said coal liquefaction zones.

Imidazole-based deep eutectic solvents for starch dissolution and plasticization.

PubMed

Zdanowicz, Magdalena; Spychaj, Tadeusz; Mąka, Honorata

2016-04-20

Potato starch and high-amylose starch were treated with imidazole-based deep eutectic solvents (DESs) as dissolution and plasticization media. Beside imidazole (IM) for two-component DESs preparation choline chloride (CC), glycerol (G) or carboxylic acids (citric or malic) were used. An influence of water content in starch (as well as an extra water in the starch/DES system) on polymer dissolution and plasticization processes was investigated. Dissolution and gelatinization of starch in DESs were followed via DSC and laser scanning microscopy. A rheometric characteristics revealed an influence of starch/DES system storage time on the plasticization process. The tendency to recrystallization of compression-molded-starch films was evaluated using XRD technique. High dissolution and plasticization effectiveness of CC/IM and G/IM and a low tendency to film retrogradation of thermoplasticized starch were noted. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling solid-state transformations occurring in dissolution testing.

PubMed

Laaksonen, Timo; Aaltonen, Jaakko

2013-04-15

Changes in the solid-state form can occur during dissolution testing of drugs. This can often complicate interpretation of results. Additionally, there can be several mechanisms through which such a change proceeds, e.g. solvent-mediated transformation or crystal growth within the drug material itself. Here, a mathematical model was constructed to study the dissolution testing of a material, which undergoes such changes. The model consisted of two processes: the recrystallization of the drug from a supersaturated liquid state caused by the dissolution of the more soluble solid form and the crystal growth of the stable solid form at the surface of the drug formulation. Comparison to experimental data on theophylline dissolution showed that the results obtained with the model matched real solid-state changes and that it was able to distinguish between cases where the transformation was controlled either by solvent-mediated crystallization or solid-state crystal growth. Copyright © 2013 Elsevier B.V. All rights reserved.

Dissolution enhancement of glibenclamide by solid dispersion: solvent evaporation versus a supercritical fluid-based solvent -antisolvent technique

PubMed Central

Tabbakhian, M.; Hasanzadeh, F.; Tavakoli, N.; Jamshidian, Z.

2014-01-01

Glibenclamide (GLIB) is a poorly soluble drug with formulation-dependent bioavailability. Therefore, we attempted in this study to improve GLIB dissolution rate by preparing drug solid dispersions by solvent evaporation (SE) and supercritical fluid solvent-antisolvent techniques (SCF-SAS). A D-optimal mixture design was used to investigate the effects of different ratios of HPMCE5 (50-100%), PEG6000 (0-40%), and Poloxamer407 (0-20%) on drug dissolution from different solid dispersion (SD) formulations prepared by SE. The ratios of carriers used in SCF-SAS method were HPMCE5 (fixed at 60%), PEG6000 (20-40%), and Poloxamer407 (0-20%). A constant drug: carrier weight ratio of 1:10 was used in all experiments. The SDs obtained were physically characterized and subjected to the dissolution study. The major GLIB bands in FTIR spectra were indicative of drug integrity. The reduced intensity and the fewer number of peaks observed in X-ray diffractograms (XRD) of GLIB formulations was the indicative of at least partial transformation of crystalline to amorphous GLIB. This change and/or dilution of drug in much higher amounts of carriers present caused disappearance of distinctive endothermic peaks in differential scanning calorimetry thermograms of GLIB formulations. The model generated according to the results of the D-optimal mixture design indicated that GLIB formulations comprising HPMC (50%-60%), PEG (34-40%), and poloxamer (6-10%) had enhanced dissolution performances. As compared to SE method, the SCF-SAS technique produced formulations of higher dissolution performances, likely due to the effects of solution and the supercritical CO2 (SC-CO2) on enhanced plasticization of polymers and thus increased diffusion of the drug into the polymer matrix. PMID:25657806

Biopolymer Processing Using Ionic Liquids

DTIC Science & Technology

2014-08-07

solvents and catalysts for the dissolution and degradation of chitin and chitosan. This project will:1) synthesis various IL catalysts to study their...effects on depolymerization of chitin and chitosan, 2) synthesis a variety of IL’s to invesitgate the effects of dissolution solvents on the rate of...chitin. The current state of technology has focused on the short-chained imidazolium cations with the chloride and acetate anion. This project will

Cellulose Crystal Dissolution in Imidazolium-Based Ionic Liquids: A Theoretical Study.

PubMed

Uto, Takuya; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

2018-01-11

The highly crystalline nature of cellulose results in poor processability and solubility, necessitating the search for solvents that can efficiently dissolve this material. Thus, ionic liquids (ILs) have recently been shown to be well suited for this purpose, although the corresponding dissolution mechanism has not been studied in detail. Herein, we adopt a molecular dynamics (MD) approach to study the dissolution of model cellulose crystal structures in imidazolium-based ILs and gain deep mechanistic insights, demonstrating that dissolution involves IL penetration-induced cleavage of hydrogen bonds between cellulose molecular chains. Moreover, we reveal that in ILs with high cellulose dissolving power (powerful solvents, such as 1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium chloride), the above molecular chains are peeled from the crystal phase and subsequently dispersed in the solvent, whereas no significant structural changes are observed in poor-dissolving-power solvents. Finally, we utilize MD trajectory analysis to show that the solubility of microcrystalline cellulose is well correlated with the number of intermolecular hydrogen bonds in cellulose crystals. The obtained results allow us to conclude that both anions and cations of high-dissolving-power ILs contribute to the stepwise breakage of hydrogen bonds between cellulose chains, whereas this breakage does not occur to a sufficient extent in poorly solubilizing ILs.

Process for producing fluid fuel from coal

DOEpatents

Hyde, Richard W.; Reber, Stephen A.; Schutte, August H.; Nadkarni, Ravindra M.

1977-01-01

Process for producing fluid fuel from coal. Moisture-free coal in particulate form is slurried with a hydrogen-donor solvent and the heated slurry is charged into a drum wherein the pressure is so regulated as to maintain a portion of the solvent in liquid form. During extraction of the hydrocarbons from the coal, additional solvent is added to agitate the drum mass and keep it up to temperature. Subsequently, the pressure is released to vaporize the solvent and at least a portion of the hydrocarbons extracted. The temperature of the mass in the drum is then raised under conditions required to crack the hydrocarbons in the drum and to produce, after subsequent stripping, a solid coke residue. The hydrocarbon products are removed and fractionated into several cuts, one of which is hydrotreated to form the required hydrogen-donor solvent while other fractions can be hydrotreated or hydrocracked to produce a synthetic crude product. The heaviest fraction can be used to produce ash-free coke especially adapted for hydrogen manufacture. The process can be made self-sufficient in hydrogen and furnishes as a by-product a solid carbonaceous material with a useful heating value.

A three step supercritical process to improve the dissolution rate of eflucimibe.

PubMed

Rodier, Elisabeth; Lochard, Hubert; Sauceau, Martial; Letourneau, Jean-Jacques; Freiss, Bernard; Fages, Jacques

2005-10-01

The aim of this study is to improve the dissolution properties of a poorly-soluble active substance, Eflucimibe by associating it with gamma-cyclodextrin. To achieve this objective, a new three-step process based on supercritical fluid technology has been proposed. First, Eflucimibe and cyclodextrin are co-crystallized using an anti-solvent process, dimethylsulfoxide being the solvent and supercritical carbon dioxide being the anti-solvent. Second, the co-crystallized powder is held in a static mode under supercritical conditions for several hours. This is the maturing step. Third, in a final stripping step, supercritical CO(2) is flowed through the matured powder to extract the residual solvent. The coupling of the first two steps brings about a significant synergistic effect to improve the dissolution rate of the drug. The nature of the entity obtained at the end of each step is discussed and some suggestions are made as to what happens in these operations. It is shown the co-crystallization ensures a good dispersion of both compounds and is rather insensitive to the operating parameters tested. The maturing step allows some dissolution-recrystallization to occur thus intensifying the intimate contact between the two compounds. Addition of water is necessary to make maturing effective as this is governed by the transfer properties of the medium. The stripping step allows extraction of the residual solvent but also removes some of the Eflucimibe which is the main drawback of this final stage.

Co-liquefaction of Elbistan Lignite with Manure Biomass; Part 2 - Effect of Biomass Type, Waste to Lignite Ratio and Solid to Liquid Ratio

NASA Astrophysics Data System (ADS)

Karaca, Hüseyin; Koyunoglu, Cemil

2017-12-01

Most coal hydrogenation processes require a large quantity of hydrogen. In general, a coal derived liquid such as anthracene oil was used as a hydrogen donor solvent. Tetralin, partially hydrogenated pyrene, phenantrene and coal-derived solvents, which contain hydroaromatic compounds, are efficient solvents to donate hydrogen. In an attempt to reduce the high cost of hydrogen, part of the hydrogen was replaced by a low cost hydrogen donor solvent. This must be hydrogenated during or before the process and recycled. To reduce the cost of hydrogen donor vehicles instead of liquids recycled from the liquefaction process or several biomass types, industrial by products, liquid fractions derived from oil sands bitumen were successfully used to solubilize a coal from the past. In an attempt to reduce the high cost of hydrogen, part of the hydrogen was replaced by a low cost hydrogen donor solvent. However, when hydrogen is supplied from the hydroaromatic structures present in the solvent, the activity of coal minerals is too low to rehydrogenate the solvent in-situ. Nevertheless, a decrease of using oxygen, in addition to enhanced usage of the hydrogen supply by using various waste materials might lead to a decrease of the cost of the liquefaction procedure. So instead of using tetralin another feeding material such as biomass is becoming another solution improving hydrogen donor substances. Most of the liquefaction process were carried out in a batch reactor, in which the residence time of the liquefaction products is long enough to favour the retrogressive reactions, early studies which are related to liquefaction of coal with biomass generally focus on the synergetic effects of coal while biomass added. Early studies which are related to liquefaction of coal with biomass generally focus on the synergetic effects of coal while biomass added. Alternatively, to understand the hydrogen transfer from biomass to coal, in this study, Elbistan Lignite (EL) with manure, tea pulp and waste plastic liquefied and to understand hydrogen quantity change after liquefaction, (H/C)atomic ratio of products obtained. Due to the highest oil conversion of manure biomass and highest (H/C)atomic ratio results show manure is the favourable biomass for EL amongst the other biomass used. And liquid/solid ratio optimized. About high total conversion of oil products the optimum ratio obtained as 3/1. And also EL with manure liquefied with the w/EL ratio between 0:1 to 1:1. As a result, by thinking about the yield values obtained, the optimum waste to lignite ratio found to be 1:1.

Through the looking glass: Unraveling the network structure of coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregory, D. M.; Stec, D. F.; Botto, R. E.

1999-12-23

Since the original idea by Sanada and Honda of treating coal as a three-dimensional cross-linked network, coal structure has been probed by monitoring ingress of solvents using traditional volumetric or gravimetric methods. However, using these techniques has allowed only an indirect observation of the swelling process. More recently, the authors have developed magnetic resonance microscopy (MRM) approaches for studying solvent ingress in polymeric systems, about which fundamental aspects of the swelling process can be deduced directly and quantitatively. The aim of their work is to utilize solvent transport and network response parameters obtained from these methods to assess fundamental propertiesmore » of the system under investigation. Polymer and coal samples have been studied to date. Numerous swelling parameters measured by magnetic resonance microscopy are found to correlate with cross-link density of the polymer network under investigation. Use of these parameters to assess the three-dimensional network structure of coal is discussed.« less

Sequential solvent extraction for the modes of occurrence of selenium in coals of different ranks from the Huaibei Coalfield, China

USGS Publications Warehouse

Zhang, Y.; Liu, Gaisheng; Chou, C.-L.; Wang, L.; Kang, Y.

2007-01-01

Forms of selenium in bituminous coal, anthracite, and cokeite (natural coke) from Huaibei Coalfield, Anhui, China, have been determined by sequential solvent extraction. The selenium content in bulk samples is 4.0, 2.4, and 2.0 ??g/g in bituminous coal, anthracite, and cokeite, respectively. The six forms of selenium determined by six-step solvent extraction are water-leachable, ion-exchangeable, organic matter-associated, carbonate-associated, silicate-associated, and sulfide-associated. The predominant forms of selenium in bituminous coal are organic matter-associated (39.0%), sulfide-associated (21.1%), and silicate bound (31.8%); these three forms account for 92% of the total. The organic matter bound-selenium decrease dramatically from bituminous coal (39.0%) to anthracite (11.6%) and to cokeite (0%), indicating that organic matter bound selenium is converted to other forms during metamorphism of the coal, most likely sulfide-form. The sulfide-associated form increased remarkably from bituminous coal (21.1%) to anthracite (50.4%) and cokeite (54.5%), indicating the formation of selenium sulfide, possibly in pyrite during the transformation of bituminous coal to anthracite and cokeite. The silicate-associated selenium in bituminous coal (31.8%) is much higher than that in anthracite (16.4%) and cokeite (15.8%), indicating that silicate-associated selenium is partly converted to sulfide during metamorphism. ?? 2007 Zhang et al; licensee BioMed Central Ltd.

Effect of Tryptophan and Asparagine Structure on the Enthalpic Characteristics of Their Dissolution in Aqueous Solutions of Sodium Dodecyl Sulfate

NASA Astrophysics Data System (ADS)

Mezhevoi, I. N.; Badelin, V. G.; Tyunina, E. Yu.; Kamkina, S. V.

2018-03-01

The integral enthalpies of dissolution of L-tryptophan and L-asparagine in aqueous solutions of sodium dodecyl sulfate (surfactant) at surfactant concentrations of up to 0.05 mol/kg of the solvent are determined and estimated calorimetrically. Standard values of the enthalpies of dissolution and transfer of amino acids from water to a mixed solvent are calculated. The calculated enthalpy coefficients of pair interactions between amino acids and surfactant molecules have positive values. Hydrophobic interactions between amino acids and surfactants have the dominant effect on the enthalpy characteristics of the interaction in a three-component solution.

Catalytic coal liquefaction process

DOEpatents

Garg, D.; Sunder, S.

1986-12-02

An improved process for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a solvent comprises using as catalyst a mixture of a 1,2- or 1,4-quinone and an alkaline compound, selected from ammonium, alkali metal, and alkaline earth metal oxides, hydroxides or salts of weak acids. 1 fig.

Catalytic coal liquefaction process

DOEpatents

Garg, Diwakar; Sunder, Swaminathan

1986-01-01

An improved process for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a solvent comprises using as catalyst a mixture of a 1,2- or 1,4-quinone and an alkaline compound, selected from ammonium, alkali metal, and alkaline earth metal oxides, hydroxides or salts of weak acids.

Sequential solvent extraction for forms of antimony in five selected coals

USGS Publications Warehouse

Qi, C.; Liu, Gaisheng; Kong, Y.; Chou, C.-L.; Wang, R.

2008-01-01

Abundance of antimony in bulk samples has been determined in five selected coals, three coals from Huaibei Coalfield, Anhui, China, and two from the Illinois Basin in the United States. The Sb abundance in these samples is in the range of 0.11-0.43 ??g/g. The forms of Sb in coals were studied by sequential solvent extraction. The six forms of Sb are water soluble, ion changeable, organic matter bound, carbonate bound, silicate bound, and sulfide bound. Results of sequential extraction show that silicate-bound Sb is the most abundant form in these coals. Silicate- plus sulfide-bound Sb accounts for more than half of the total Sb in all coals. Bituminous coals are higher in organic matterbound Sb than anthracite and natural coke, indicating that the Sb in the organic matter may be incorporated into silicate and sulfide minerals during metamorphism. ?? 2008 by The University of Chicago. All rights reserved.

Aspects of Solvent Chemistry for Calcium Hydroxide Medicaments

PubMed Central

Athanassiadis, Basil

2017-01-01

Calcium hydroxide pastes have been used in endodontics since 1947. Most current calcium hydroxide endodontic pastes use water as the vehicle, which limits the dissolution of calcium hydroxide that can be achieved and, thereby, the maximum pH that can be achieved within the root canal system. Using polyethylene glycol as a solvent, rather than water, can achieve an increase in hydroxyl ions release compared to water or saline. By adopting non-aqueous solvents such as the polyethylene glycols (PEG), greater dissolution and faster hydroxyl ion release can be achieved, leading to enhanced antimicrobial actions, and other improvements in performance and biocompatibility. PMID:29065542

Preparation of olanzapine and methyl-β-cyclodextrin complexes using a single-step, organic solvent-free supercritical fluid process: An approach to enhance the solubility and dissolution properties.

PubMed

Rudrangi, Shashi Ravi Suman; Trivedi, Vivek; Mitchell, John C; Wicks, Stephen Richard; Alexander, Bruce David

2015-10-15

The purpose of this study was to evaluate a single-step, organic solvent-free supercritical fluid process for the preparation of olanzapine-methyl-β-cyclodextrin complexes with an express goal to enhance the dissolution properties of olanzapine. The complexes were prepared by supercritical carbon dioxide processing, co-evaporation, freeze drying and physical mixing. The prepared complexes were then analysed by differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, solubility and dissolution studies. Computational molecular docking studies were performed to study the formation of molecular inclusion complexation of olanzapine with methyl-β-cyclodextrin. All the binary mixtures of olanzapine with methyl-β-cyclodextrin, except physical mixture, exhibited a faster and greater extent of drug dissolution than the drug alone. Products obtained by the supercritical carbon dioxide processing method exhibited the highest apparent drug dissolution. The characterisation by different analytical techniques suggests complete complexation or amorphisation of olanzapine and methyl-β-cyclodextrin complexes prepared by supercritical carbon dioxide processing method. Therefore, organic solvent-free supercritical carbon dioxide processing method proved to be novel and efficient for the preparation of solid inclusion complexes of olanzapine with methyl-β-cyclodextrin. The preliminary data also suggests that the complexes of olanzapine with methyl-β-cyclodextrin will lead to better therapeutic efficacy due to better solubility and dissolution properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Process for hydrogenation of hydrocarbon tars

DOEpatents

Dolbear, Geoffrey E.

1978-07-18

Hydrocarbon tars of high asphaltene content such as tars obtained from pyrolysis of coal are dissolved in a solvent formed from the hydrogenation of the coal tars, and the resultant mixture hydrogenated in the presence of a catalyst at a pressure from about 1500 to 5000 psig at a temperature from about 500.degree. F to about the critical temperature of the solvent to form a light hydrocarbon as a solvent for the tars. Hydrogen content is at least three times the amount of hydrogen consumed.

Production of pure indinavir free base nanoparticles by a supercritical anti-solvent (SAS) method.

PubMed

Imperiale, Julieta C; Bevilacqua, Gabriela; Rosa, Paulo de Tarso Vieira E; Sosnik, Alejandro

2014-12-01

This work investigated the production of pure indinavir free base nanoparticles by a supercritical anti-solvent method to improve the drug dissolution in intestine-like medium. To increase the dissolution of the drug by means of a supercritical fluid processing method. Acetone was used as solvent and supercritical CO2 as antisolvent. Products were characterized by dynamic light scattering (size, size distribution), scanning electron microscopy (morphology), differential scanning calorimetry (thermal behaviour) and X-rays diffraction (crystallinity). Processed indinavir resulted in particles of significantly smaller size than the original drug. Particles showed at least one dimension at the nanometer scale with needle or rod-like morphology. Results of X-rays powder diffraction suggested the formation of a mixture of polymorphs. Differential scanning calorimetry analysis showed a main melting endotherm at 152 °C. Less prominent transitions due to the presence of small amounts of bound water (in the raw drug) or an unstable polymorph (in processed IDV) were also visible. Finally, drug particle size reduction significantly increased the dissolution rate with respect to the raw drug. Conversely, the slight increase of the intrinsic solubility of the nanoparticles was not significant. A supercritical anti-solvent method enabled the nanonization of indinavir free base in one single step with high yield. The processing led to faster dissolution that would improve the oral bioavailability of the drug.

Research on the Composition and Distribution of Organic Sulfur in Coal.

PubMed

Zhang, Lanjun; Li, Zenghua; Yang, Yongliang; Zhou, Yinbo; Li, Jinhu; Si, Leilei; Kong, Biao

2016-05-13

The structure and distribution of organic sulfur in coals of different rank and different sulfur content were studied by combining mild organic solvent extraction with XPS technology. The XPS results have shown that the distribution of organic sulfur in coal is related to the degree of metamorphism of coal. Namely, thiophenic sulfur content is reduced with decreasing metamorphic degree; sulfonic acid content rises with decreasing metamorphic degree; the contents of sulfate sulfur, sulfoxide and sulfone are rarely related with metamorphic degree. The solvent extraction and GC/MS test results have also shown that the composition and structure of free and soluble organic sulfur small molecules in coal is closely related to the metamorphic degree of coal. The free organic sulfur small molecules in coal of low metamorphic degree are mainly composed of aliphatic sulfides, while those in coal of medium and high metamorphic degree are mainly composed of thiophenes. Besides, the degree of aromatization of organic sulfur small molecules rises with increasing degree of coalification.

Highly dispersed catalysts for coal liquefaction. Quarterly report No. 9, August 23, 1993--November 22, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirschon, A.S.; Wilson, R.B.

We analyzed two sets of liquefaction experiments, one involved the liquefaction of Black Thunder Coal with the corresponding recycle vehicle, and the second set of liquefaction runs involved the liquefaction of Argonne North Dakota Lignite. We compared coal conversions of Black Thunder coal and recycle solvent using Fe(CO){sub 5} and carbon monoxide/hydrogen atmospheres and a MolyVanL molybdenum catalyst under a hydrogen atmosphere. We also continued our investigation of the effect of water on the conversions. We found that addition of water seemed to decrease the amount of oils; we determined the effect of water with the recycle solvent alone, (nomore » coal added) under similar conditions, and again produced a decrease in oil yields. FIMS analyses of the hexane and toluene soluble fractions seem to indicate that in the experiment when water was added, a considerable amount of light material remained behind in the toluene layer, suggesting that somehow the addition of water decreased the amount of extracted material, perhaps by increasing the amount of polarity of the product. When the conversion was conducted with the MolyVanL molybdenum catalyst a good quality product in terms of lower viscosity was produced; however, conversions to THF soluble material was not increased. We believe the molybdenum catalyst hydrogenated the recycle vehicle rather than effectively converted the coal. In order to eliminate the effect of solvent we have often conducted experiments in an inert solvent with Argonne coals. We conducted several coal conversions experiments using an Argonne North Dakota lignite. We compared several dispersed Fe catalysts and in addition, a nickel catalyst. We investigated nickel as a catalyst since we believe this metal may be more effective in decarboxylating low rank coals. Consistent with this premise we found that the nickel catalyst gave the highest conversions.« less

Automated apparatus for solvent separation of a coal liquefaction product stream

DOEpatents

Schweighardt, Frank K.

1985-01-01

An automated apparatus for the solvent separation of a coal liquefaction product stream that operates continuously and unattended and eliminates potential errors resulting from subjectivity and the aging of the sample during analysis. In use of the apparatus, metered amounts of one or more solvents are passed sequentially through a filter containing the sample under the direction of a microprocessor control means. The mixture in the filter is agitated by means of ultrasonic cavitation for a timed period and the filtrate is collected. The filtrate of each solvent extraction is collected individually and the residue on the filter element is collected to complete the extraction process.

Process for producing low-sulfur boiler fuel by hydrotreatment of solvent deashed SRC

DOEpatents

Roberts, George W.; Tao, John C.

1985-01-01

In this invention, a process is disclosed characterized by heating a slurry of coal in the presence of a process-derived recycle solvent and passing same to a dissolver zone, separating the resultant gases and liquid/solid products therefrom, vacuum distilling the liquid/solids products, separating the portions of the liquid/solids vacuum distillation effluent into a solid ash, unconverted coal particles and SRC material having a boiling point above 850.degree. F. and subjecting same to a critical solvent deashing step to provide an ash-free SRC product. The lighter liquid products from the vacuum distillation possess a boiling point below 850.degree. F. and are passed through a distillation tower, from which recycled solvent is recovered in addition to light distillate boiling below 400.degree. F. (overhead). The ash-free SRC product in accompanyment with at least a portion of the process derived solvent is passed in combination to a hydrotreating zone containing a hydrogenation catalyst and in the presence of hydrogen is hydroprocessed to produce a desulfurized and denitrogenized low-sulfur, low-ash boiler fuel and a process derived recycle solvent which is recycled to slurry the coal in the beginning of the process before heating.

Quantitation of buried contamination by use of solvents

NASA Technical Reports Server (NTRS)

Pappas, S. P.; Hsiao, P.; Hill, L. W.

1972-01-01

Solubilization studies were carried out on various cured silicone resins. A solvent spectrum was prepared. It was found that complete dissolution of cured silicone resins could be achieved without extensive physical degradation of samples. Based on the solubilization results, amine solvents were selected for spore viability studies.

Factors governing dissolution process of lignocellulosic biomass in ionic liquid: current status, overview and challenges.

PubMed

Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

2015-02-01

The utilisation of non-feed lignocellulosic biomass as a source of renewable bio-energy and synthesis of fine chemical products is necessary for the sustainable development. The methods for the dissolution of lignocellulosic biomass in conventional solvents are complex and tedious due to the complex chemical ultra-structure of biomass. In view of this, recent developments for the use of ionic liquid solvent (IL) has received great attention, as ILs can solubilise such complex biomass and thus provides industrial scale-up potential. In this review, we have discussed the state-of-art for the dissolution of lignocellulosic material in representative ILs. Furthermore, various process parameters and their influence for biomass dissolution were reviewed. In addition to this, overview of challenges and opportunities related to this interesting area is presented. Copyright © 2014 Elsevier Ltd. All rights reserved.

Energetics of the molecular interactions of L-cysteine, L-serine, and L-asparagine in aqueous propylene glycol solutions at 298.15 K

NASA Astrophysics Data System (ADS)

Mezhevoi, I. N.; Badelin, V. G.

2015-03-01

Integral enthalpies of dissolution Δsol H m of L-cysteine, L-serine, and L-asparagine in aqueous solutions of 1,3-propylene glycol at organic solvent concentrations of up to 0.26 mole fraction are measured via the thermochemistry of dissolution. Standard enthalpies of dissolution (Δsol H ○) and transfer (Δtr H ○) of amino acids from water to a mixed solvent are calculated. It is found that the calculated enthalpy coefficients of pair interactions of the amino acids with polyhydric alcohol molecules have positive values. The effect the arrangement of the hydroxyl group in the structure of polyhydric alcohols has on the enthalpy of interaction of amino acids in aqueous solutions is revealed. The effect of different types of interactions in solutions and the structural features of biomolecules and cosolvents on the enthalpy of dissolution of amino acids is analyzed.

Microwave-assisted extraction of polycyclic aromatic compounds from coal.

PubMed

Kerst, M; Andersson, J T

2001-08-01

Microwave-assisted extraction (MAE) of polycyclic aromatic compounds (PACs) from coal is shown to give the same pattern of compounds as Soxhlet extraction. MAE requires only 10 mL solvent and 10 min extraction time whereas Soxhlet uses 200 mL and takes 24 h. Although the yields were lower, dichloromethane (DCM) was preferred to pyridine, N-methyl-2-pyrrolidone (NMP), and NMP with CS2 because the pattern of the PACs is shown to be independent of solvent and DCM is a much more convenient solvent to work with.

Advanced direct coal liquefaction concepts. Quarterly report, April 1, 1993--June 30, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

Construction and commissioning of the bench unit for operation of the first stage of the process was completed. Solubilization of Black Thunder coal using carbon monoxide and steam was successfully demonstrated in the counterflow reactor system. The results were comparable with those obtained in the autoclave with the exception that coal solubilization at the same nominal residence times was slightly lower. The bench unit has now been modified for two stage operation. The Wilsonville process derived solvent for Black Thunder coal (V-1074) was found to be essentially as stable as the previous solvent used in the autoclave runs (V-178 +more » 320) at reactor conditions. This solvent (V-1074) is, therefore, being used in the bench unit tests. Carbon monoxide may be replaced by synthesis gas for the coal solubilization step in the process. However, in autoclave tests, coal conversion was found to be dependent on the amount of carbon monoxide present in the synthesis gas. Coal conversions ranged from 88% for pure carbon monoxide to 67% for a 25:75 carbon monoxide/hydrogen mixture at equivalent conditions. Two stage liquefaction tests were completed in the autoclave using a disposable catalyst (FeS) and hydrogen in the second stage. Increased coal conversion, higher gas and oil and lower asphaltene and preasphaltene yields were observed as expected. However, no hydrogen consumption was observed in the second stage. Other conditions, in particular, alternate catalyst systems will be explored.« less

Advanced direct coal liquefaction concepts. Quarterly report, January 1, 1993--March 31, 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

1993-07-01

Five barrels of a Wilsonville process derived solvent (V-1074) from Black Thunder coal were obtained. This material boils within the preferred gas oil range, is more aromatic than previous solvents, and will therefore be used for the bench unit studies. Several repeat runs were performed in the autoclave to confirm the results of the matrix study. In addition, runs were carried out with different catalysts, with agglomerates and with the V-1074 solvent. The results of the autoclave runs were analyzed with respect to coal conversion, CO conversion, oil yield, hydrogen consumption and oxygen removal. It was concluded that the bestmore » operating conditions for the first stage operation was a temperature of at least 390{degrees}C, residence time of at least 30 minutes, cold CO pressure of at least 600 psig and potassium carbonate catalyst (2% wt on total feed). The data also indicated however, that the coal conversion goes through a maximum, and too high a severity leads to retrograde reaction and lower coal solubilization. The scope for increasing temperature and time is therefore limited. Petrographic examination of the THF insoluble resids from the autoclave program indicated a maximum coal conversion of about 90% for Black Thunder coal. The bench unit construction was also essentially completed and the bench unit program to be carded out in the next twelve months was defined.« less

Liquigroud technique: a new concept for enhancing dissolution rate of glibenclamide by combination of liquisolid and co-grinding technologies.

PubMed

Azharshekoufeh, Leila; Shokri, Javad; Barzegar-Jalali, Mohammad; Javadzadeh, Yousef

2017-01-01

Introduction: The potential of combining liquisolid and co-grinding technologies (liquiground technique) was investigated to improve the dissolution rate of a water-insoluble agent (glibenclamide) with formulation-dependent bioavailability. Methods: To this end, different formulations of liquisolid tablets with a wide variety of non-volatile solvents contained varied ratios of drug: solvent and dissimilar carriers were prepared, and then their release profiles were evaluated. Furthermore, the effect of size reduction by ball milling on the dissolution behavior of glibenclamide from liquisolid tablets was investigated. Any interaction between the drug and the excipient or crystallinity changes during formulation procedure was also examined using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results: The present study revealed that classic liquisolid technique did not significantly affect the drug dissolution profile as compared to the conventional tablets. Size reduction obtained by co-grinding of liquid medication was more effective than the implementation of liquisolid technique in enhancing the dissolution rate of glibenclamide. The XRD and DSC data displayed no formation of complex or any crystallinity changes in both formulations. Conclusion: An enhanced dissolution rate of glibenclamide is achievable through the combination of liquisolid and co-grinding technologies.

Research on solvent-refined coal. Quarterly technical progress report, April 1, 1981-June 30, 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-10-01

This report describes progress on the Research on Solvent Refined Coal project by The Pittsburg and Midway Coal Mining Co.'s Merriam Laboratory during the second quarter of 1981. Alexander Mine coal was evaluated as a feedstock for major liquefaction facilities and had a yield structure similar to other reactive Pittsburgh seam coals at standard SRC II conditions. Two lots of coal from the Ireland Mine (Pittsburgh seam) were found to be of nearly the same composition and produced essentially the same yields. Two experiments in which coal-derived nonvolatile organic matter was processed without fresh coal feed indicate constant rates ofmore » conversion of SRC to oil and gas. Insoluble organic matter (IOM) remained unconverted. The naphtha and middle distillate products from the deep conversion contained less sulfur but more nitrogen than those from conventional SRC II processing. Encouraging results were obtained when a very small amount of iron oxide dispersed on alumina was added to Kaiparowits coal which cannot be processed at normal SRC II conditions without added catalyst. Subbituminous coals from the McKinley and Edna Mines were processed successfully with added pyrite but would not run when the added catalyst was removed.« less

Isotopic evidence of enhanced carbonate dissolution at a coal mine drainage site in Allegheny County, Pennsylvania, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Shikha; Sack, Andrea; Adams, James P.

Stable isotopes were used to determine the sources and fate of dissolved inorganic C (DIC) in the circumneutral pH drainage from an abandoned bituminous coal mine in western Pennsylvania. The C isotope signatures of DIC (δ{sup 13}C{sub DIC}) were intermediate between local carbonate and organic C sources, but were higher than those of contemporaneous Pennsylvanian age groundwaters in the region. This suggests a significant contribution of C enriched in {sup 13}C due to enhanced carbonate dissolution associated with the release of H{sub 2}SO{sub 4} from pyrite oxidation. The Sr isotopic signature of the drainage was similar to other regional minemore » waters associated with the same coal seam and reflected contributions from limestone dissolution and cation exchange with clay minerals. The relatively high δ{sup 34}S{sub SO4} and δ{sup 18}O{sub SO4} isotopic signatures of the mine drainage and the presence of presumptive SO{sub 4}-reducing bacteria suggest that SO{sub 4} reduction activity also contributes C depleted in {sup 13}C isotope to the total DIC pool. With distance downstream from the mine portal, C isotope signatures in the drainage increased, accompanied by decreased total DIC concentrations and increased pH. These data are consistent with H{sub 2}SO{sub 4} dissolution of carbonate rocks, enhanced by cation exchange, and C release to the atmosphere via CO{sub 2} outgassing.« less

Mobil process converts methanol to high-quality synthetic gasoline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, A.

1978-12-11

If production of gasoline from coal becomes commercially attractive in the United States, a process under development at the Mobil Research and Development Corp. may compete with better known coal liquefaction processes. Mobil process converts methanol to high-octane, unleaded gasoline; methanol can be produced commercially from coal. If gasoline is the desired product, the Mobil process offers strong technical and cost advantages over H-coal, Exxon donor solvent, solvent-refined coal, and Fischer--Tropsch processes. The cost analysis, contained in a report to the Dept. of Energy, concludes that the Mobil process produces more-expensive liquid products than any other liquefaction process except Fischer--Tropsch.more » But Mobil's process produces ready-to-use gasoline, while the others produce oils which require further expensive refining to yield gasoline. Disadvantages and advantages are discussed.« less

Homogeneous catalytic hydrogenations of complex carbonaceous substrates. [16 references

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, J L; Wilcox, W A; Roberts, G L

1976-11-05

Results of homogeneous catalytic hydrogenation of complex unsaturated substrates including coal and coal-derived materials are reported, with organic soluble molecular complexes as catalysts. Among the substrates used were Hvab coal, solvent-refined coal, and COED pyrolysate. The hydrogenations were carried out in an autoclave. The results are summarized in tables.

Superconcentrated electrolytes for a high-voltage lithium-ion battery

PubMed Central

Wang, Jianhui; Yamada, Yuki; Sodeyama, Keitaro; Chiang, Ching Hua; Tateyama, Yoshitaka; Yamada, Atsuo

2016-01-01

Finding a viable electrolyte for next-generation 5 V-class lithium-ion batteries is of primary importance. A long-standing obstacle has been metal-ion dissolution at high voltages. The LiPF6 salt in conventional electrolytes is chemically unstable, which accelerates transition metal dissolution of the electrode material, yet beneficially suppresses oxidative dissolution of the aluminium current collector; replacing LiPF6 with more stable lithium salts may diminish transition metal dissolution but unfortunately encounters severe aluminium oxidation. Here we report an electrolyte design that can solve this dilemma. By mixing a stable lithium salt LiN(SO2F)2 with dimethyl carbonate solvent at extremely high concentrations, we obtain an unusual liquid showing a three-dimensional network of anions and solvent molecules that coordinate strongly to Li+ ions. This simple formulation of superconcentrated LiN(SO2F)2/dimethyl carbonate electrolyte inhibits the dissolution of both aluminium and transition metal at around 5 V, and realizes a high-voltage LiNi0.5Mn1.5O4/graphite battery that exhibits excellent cycling durability, high rate capability and enhanced safety. PMID:27354162

Hydroliquefaction of coal

DOEpatents

Sze, Morgan C.; Schindler, Harvey D.

1982-01-01

Coal is catalytically hydroliquefied by passing coal dispersed in a liquefaction solvent and hydrogen upwardly through a plurality of parallel expanded catalyst beds, in a single reactor, in separate streams, each having a cross-sectional flow area of no greater than 255 inches square, with each of the streams through each of the catalyst beds having a length and a liquid and gas superficial velocity to maintain an expanded catalyst bed and provide a Peclet Number of at least 3. If recycle is employed, the ratio of recycle to total feed (coal and liquefaction solvent) is no greater than 2:1, based on volume. Such conditions provide for improved selectivity to liquid product to thereby reduce hydrogen consumption. The plurality of beds are formed by partitions in the reactor.

Solvent screening for a hard-to-dissolve molecular crystal.

PubMed

Maiti, A; Pagoria, P F; Gash, A E; Han, T Y; Orme, C A; Gee, R H; Fried, L E

2008-09-01

Materials with a high-degree of inter- and intra-molecular hydrogen bonding generally have limited solubility in conventional organic solvents. This presents a problem for the dissolution, manipulation and purification of these materials. Using a state-of-the-art density-functional-theory based quantum chemical solvation model we systematically evaluated solvents for a known hydrogen-bonded molecular crystal. This, coupled with direct solubility measurements, uncovered a class of ionic liquids involving fluoride anions that possess more than two orders of magnitude higher solvation power as compared with the best conventional solvents. The crystal structure of one such ionic liquid, determined by X-ray diffraction spectroscopy, indicates that F- ions are stabilized through H-bonded chains with water. The presence of coordinating water in such ionic liquids seems to facilitate the dissolution process by keeping the chemical activity of the F- ions in check.

Mesoscale Polymer Dissolution Probed by Raman Spectroscopy and Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Tsun-Mei; Xantheas, Sotiris S.; Vasdekis, Andreas E.

2016-10-13

The diffusion of various solvents into a polystyrene (PS) matrix was probed experimentally by monitoring the temporal profiles of the Raman spectra and theoretically from molecular dynamics (MD) simulations of the binary system. The simulation results assist in providing a fundamental, molecular level connection between the mixing/dissolution processes and the difference = solvent – PS in the values of the Hildebrand parameter () between the two components of the binary systems: solvents having similar values of with PS (small ) exhibit fast diffusion into the polymer matrix, whereas the diffusion slows down considerably when the ’s are different (large ).more » To this end, the Hildebrand parameter was identified as a useful descriptor that governs the process of mixing in polymer – solvent binary systems. The experiments also provide insight into further refinements of the models specific to non-Fickian diffusion phenomena that need to be used in the simulations.« less

Two-stage coal liquefaction process

DOEpatents

Skinner, Ronald W.; Tao, John C.; Znaimer, Samuel

1985-01-01

An improved SRC-I two-stage coal liquefaction process which improves the product slate is provided. Substantially all of the net yield of 650.degree.-850.degree. F. heavy distillate from the LC-Finer is combined with the SRC process solvent, substantially all of the net 400.degree.-650.degree. F. middle distillate from the SRC section is combined with the hydrocracker solvent in the LC-Finer, and the initial boiling point of the SRC process solvent is increased sufficiently high to produce a net yield of 650.degree.-850.degree. F. heavy distillate of zero for the two-stage liquefaction process.

Anodic Behavior of the Aluminum Current Collector in Imide-Based Electrolytes: Influence of Solvent, Operating Temperature, and Native Oxide-Layer Thickness.

PubMed

Meister, Paul; Qi, Xin; Kloepsch, Richard; Krämer, Elisabeth; Streipert, Benjamin; Winter, Martin; Placke, Tobias

2017-02-22

The inability of imide salts to form a sufficiently effective passivation layer on aluminum current collectors is one of the main obstacles that limit their broad application in electrochemical energy-storage systems. However, under certain circumstances, the use of electrolytes with imide electrolyte salts in combination with the aluminum current collector is possible. In this contribution, the stability of the aluminum current collector in electrolytes containing either lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) or lithium fluorosulfonyl-(trifluoromethanesulfonyl) imide (LiFTFSI) as conductive salt was investigated by electrochemical techniques, that is, cyclic voltammetry (CV) and chronocoulometry (CC) in either room-temperature ionic liquids or in ethyl methyl sulfone. In particular, the influence of the solvent, operating temperature, and thickness of the native oxide layer of aluminum on the pit formation at the aluminum current collector surface was studied by means of scanning electron microscopy. In general, a more pronounced aluminum dissolution and pit formation was found at elevated temperatures as well as in solvents with a high dielectric constant. An enhanced thickness of the native aluminum oxide layer increases the oxidative stability versus dissolution. Furthermore, we found a different reaction rate depending on dwell time at the upper cut-off potential for aluminum dissolution in TFSI- and FTFSI-based electrolytes during the CC measurements; the use of LiFTFSI facilitated the dissolution of aluminum compared to LiTFSI. Overall, the mechanism of anodic aluminum dissolution is based on: i) the attack of the Al 2 O 3 surface by acidic species and ii) the dissolution of bare aluminum into the electrolyte, which, in turn, is influenced by the electrolyte's dielectric constant. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solubility prediction of naphthalene in carbon dioxide from crystal microstructure

NASA Astrophysics Data System (ADS)

Sang, Jiarong; Jin, Junsu; Mi, Jianguo

2018-03-01

Crystals dissolved in solvents are ubiquitous in both natural and artificial systems. Due to the complicated structures and asymmetric interactions between the crystal and solvent, it is difficult to interpret the dissolution mechanism and predict solubility using traditional theories and models. Here we use the classical density functional theory (DFT) to describe the crystal dissolution behavior. As an example, naphthalene dissolved in carbon dioxide (CO2) is considered within the DFT framework. The unit cell dimensions and microstructure of crystalline naphthalene are determined by minimizing the free-energy of the crystal. According to the microstructure, the solubilities of naphthalene in CO2 are predicted based on the equality of naphthalene's chemical potential in crystal and solution phases, and the interfacial structures and free-energies between different crystal planes and solution are determined to investigate the dissolution mechanism at the molecular level. The theoretical predictions are in general agreement with the available experimental data, implying that the present model is quantitatively reliable in describing crystal dissolution.

Process for improving soluble coal yield in a coal deashing process

DOEpatents

Rhodes, Donald E.

1980-01-01

Coal liquefaction products are contacted with a deashing solvent and introduced into a first separation zone. The first separation zone is maintained at an elevated temperature and pressure, determined to maximize the recovery of soluble coal products, to cause said coal liquefaction products to separate into a first light phase and a first heavy phase. Under these conditions the heavy phase while still fluid-like in character is substantially non-flowable. Flowability is returned to the fluid-like heavy phase by the introduction of an additional quantity of deashing solvent into the first separation zone at a location below the interface between the first light and heavy phases or into the heavy phase withdrawal conduit during withdrawal of the first heavy phase and prior to any substantial pressure reduction. The first heavy phase then is withdrawn from the first separation zone for additional downstream processing without plugging either the withdrawal conduit or the downstream apparatus. The first light phase comprising the soluble coal products is withdrawn and recovered in an increased yield to provide a more economical coal deashing process.

Anodic Dissolution of Al Current Collectors in Unconventional Solvents for High Voltage Electrochemical Double-Layer Capacitors.

PubMed

Krummacher, Jakob; Heß, Lars-Henning; Balducci, Andrea

2017-09-04

This study investigated the anodic dissolution of Al current collectors in unconventional electrolytes for high voltage electrochemical double-layer capacitors (EDLCs) containing adiponitrile (ADN), 3-cyanopropionic acid methyl ester (CPAME), 2-methyl-glutaronitrile (2-MGN) as solvent, and tetraethylammonium tetrafluoroborate (Et 4 NBF 4 ) and tetraethylammonium bis(trifluoromethanesulfonyl)imide (Et 4 NTFSI) as conductive salts. To have a comparison with the state-of-the-art electrolytes, the same salts were also used in combination with acetonitrile (ACN). The chemical-physical properties of the electrolytes were investigated. Furthermore, their impact on the anodic dissolution of Al was analyzed in detail as well as the influence of this process on the performance of high voltage EDLCs. The results of this study indicated that in the case of Et 4 NBF 4 -based electrolytes, the use of an alternative solvent is very beneficial for the realization of stable devices. When Et 4 NTFSI is used, the reduced solubility of the complex Al(TFSI) 3 appears to be the key for the realization of advanced electrolytes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Automatic twin vessel recrystallizer. Effective purification of acetaminophen by successive automatic recrystallization and absolute determination of purity by DSC.

PubMed

Nara, Osamu

2011-01-24

I describe an interchangeable twin vessel (J, N) automatic glass recrystallizer that eliminates the time-consuming recovery and recycling of crystals for repeated recrystallization. The sample goes in the dissolution vessel J containing a magnetic stir-bar K; J is clamped to the upper joint H of recrystallizer body D. Empty crystallization vessel N is clamped to the lower joint M. Pure solvent is delivered to the dissolution vessel and the crystallization vessel via the head of the condenser A. Crystallization vessel is heated (P). The dissolution reservoir is stirred and heated by the solvent vapor (F). Continuous outflow of filtrate E out of J keeps N at a stable boiling temperature. This results in efficient dissolution, evaporation and separation of pure crystals Q. Pure solvent in the dissolution reservoir is recovered by suction. Empty dissolution and crystallization vessels are detached. Stirrer magnet is transferred to the crystallization vessel and the role of the vessels are then reversed. Evacuating mother liquor out of the upper twin vessel, the apparatus unit is ready for the next automatic recrystallization by refilling twin vessels with pure solvent. We show successive automatic recrystallization of acetaminophen from diethyl ether obtaining acetaminophen of higher melting temperatures than USP and JP reference standards by 8× automatic recrystallization, 96% yield at each stage. Also, I demonstrate a novel approach to the determination of absolute purity by combining the successive automatic recrystallization with differential scanning calorimetry (DSC) measurement requiring no reference standards. This involves the measurement of the criterial melting temperature T(0) corresponding to the 100% pure material and quantitative ΔT in DSC based on the van't Hoff law of melting point depression. The purity of six commercial acetaminophen samples and reference standards and an eight times recrystallized product evaluated were 98.8 mol%, 97.9 mol%, 99.1 mol%, 98.3 mol%, 98.4 mol%, 98.5 mol% and 99.3 mol% respectively. Copyright © 2010 Elsevier B.V. All rights reserved.

Ultrasound enhanced process for extracting metal species in supercritical fluids

DOEpatents

Wai, Chien M.; Enokida, Youichi

2006-10-31

Improved methods for the extraction or dissolution of metals, metalloids or their oxides, especially lanthanides, actinides, uranium or their oxides, into supercritical solvents containing an extractant are disclosed. The disclosed embodiments specifically include enhancing the extraction or dissolution efficiency with ultrasound. The present methods allow the direct, efficient dissolution of UO₂ or other uranium oxides without generating any waste stream or by-products.

Filtration of micron-sized particles for coal liquids: carbonaceous precoats. [5 refs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, B.R.

Carbonaceous precoats, such as bituminous coal and char from hydrocarbonization, are shown to be effective, inexpensive substitutes for traditional diatomaceous earth materials, both at laboratory-scale and bench-scale. Model equations are developed for filtration of Solvent Refined Coal-Unfiltered Oil (SRC-UFO).

Small angle neutron scattering applications in fuel science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thiyagarajan, P.; Cody, G.D.; Hunt, J.E.

1995-08-01

A wide range of physical and chemical methods have been used to study complex, multicomponent systems in fuel chemistry (crude oil, coal), and we are still far from complete understanding. Since chemical modification and/or solvent extraction of coal result in a number of different systems, it is important to understand the products in terms of their colloidal properties as a function of the solvent type, as well as other physical conditions. This would be helpful in design of processing techniques. Another area of research where SANS can be useful is characterization of the synthetic and modified clays being developed formore » processing in the petroleum industry. Major limitations for performing SANS experiments are nonavailability/high cost sof certain deuterated solvents and the paucity of beam time at the neutron scattering centers. This paper reports briefly on analysis of coal and asphaltenes.« less

Prevention of deleterious deposits in a coal liquefaction system

DOEpatents

Carr, Norman L.; Prudich, Michael E.; King, Jr., William E.; Moon, William G.

1984-07-03

A process for preventing the formation of deleterious coke deposits on the walls of coal liquefaction reactor vessels involves passing hydrogen and a feed slurry comprising feed coal and recycle liquid solvent to a coal liquefaction reaction zone while imparting a critical mixing energy of at least 3500 ergs per cubic centimeter of reaction zone volume per second to the reacting slurry.

Solvent Refined Coal (SRC) process. Research and development report No. 53, interim report No. 29, August-November, 1978. Volume VI. Process development unit studies. Part 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1980-01-01

This report presents the results of seven SRC-II runs on Process Development Unit P99 feeding Pittsburgh Seam coal. Four of these runs (Runs 41-44) were made feeding coal from the Robinson Run Mine and three (Runs 45-47) were made feeding a second shipment of coal from the Powhatan No. 5 Mine. This work showed that both these coals are satisfactory feedstocks for the SRC-II process. Increasing dissolver outlet hydrogen partial pressure from approximately 1300 to about 1400 psia did not have a significant effect on yields from Robinson Run coal, but simultaneously increasing coal concentration in the feed slurry frommore » 25 to 30 wt% and decreasing the percent recycle solids from 21% to 17% lowered distillate yields. With the Powhatan coal, a modest increase in the boiling temperature (approximately 35/sup 0/F) at the 10% point) of the process solvent had essentially no effect on product yields, while lowering the average dissolver temperature from 851/sup 0/F to 842/sup 0/F reduced gas yield.« less

Enthalpies of solvation for dopamine hydrochloride in water-ethanol solutions

NASA Astrophysics Data System (ADS)

Vandyshev, V. N.; Ledenkov, S. F.; Molchanov, A. S.

2012-10-01

The enthalpies of dissolution of dopamine hydrochloride (H2Dop · HCl) in water-ethanol solvents containing from 0 to 0.8 mole fraction of ethanol are measured by calorimetry at 298.15 K. Standard enthalpies of transfer (Δtr H ∘) for the molecular (H2Dop) and cationic (H3Dop+) forms of dopamine from water into binary solvents are calculated from the obtained data. The enthalpies of transfer of H3Dop+ cation are determined from the enthalpies of dissolution of H2Dop · HCl using the familiar method of separating the molar quantities into ionic contributions (Ph4P+ = BPh{4/-}), and by an original alternative procedure. The effect of the composition of the binary solvent on the solvation of dopamine is considered.

Optimization of the solvent-based dissolution method to sample volatile organic compound vapors for compound-specific isotope analysis.

PubMed

Bouchard, Daniel; Wanner, Philipp; Luo, Hong; McLoughlin, Patrick W; Henderson, James K; Pirkle, Robert J; Hunkeler, Daniel

2017-10-20

The methodology of the solvent-based dissolution method used to sample gas phase volatile organic compounds (VOC) for compound-specific isotope analysis (CSIA) was optimized to lower the method detection limits for TCE and benzene. The sampling methodology previously evaluated by [1] consists in pulling the air through a solvent to dissolve and accumulate the gaseous VOC. After the sampling process, the solvent can then be treated similarly as groundwater samples to perform routine CSIA by diluting an aliquot of the solvent into water to reach the required concentration of the targeted contaminant. Among solvents tested, tetraethylene glycol dimethyl ether (TGDE) showed the best aptitude for the method. TGDE has a great affinity with TCE and benzene, hence efficiently dissolving the compounds during their transition through the solvent. The method detection limit for TCE (5±1μg/m 3 ) and benzene (1.7±0.5μg/m 3 ) is lower when using TGDE compared to methanol, which was previously used (385μg/m 3 for TCE and 130μg/m 3 for benzene) [2]. The method detection limit refers to the minimal gas phase concentration in ambient air required to load sufficient VOC mass into TGDE to perform δ 13 C analysis. Due to a different analytical procedure, the method detection limit associated with δ 37 Cl analysis was found to be 156±6μg/m 3 for TCE. Furthermore, the experimental results validated the relationship between the gas phase TCE and the progressive accumulation of dissolved TCE in the solvent during the sampling process. Accordingly, based on the air-solvent partitioning coefficient, the sampling methodology (e.g. sampling rate, sampling duration, amount of solvent) and the final TCE concentration in the solvent, the concentration of TCE in the gas phase prevailing during the sampling event can be determined. Moreover, the possibility to analyse for TCE concentration in the solvent after sampling (or other targeted VOCs) allows the field deployment of the sampling method without the need to determine the initial gas phase TCE concentration. The simplified field deployment approach of the solvent-based dissolution method combined with the conventional analytical procedure used for groundwater samples substantially facilitates the application of CSIA to gas phase studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Controlled short residence time coal liquefaction process

DOEpatents

Anderson, Raymond P.; Schmalzer, David K.; Wright, Charles H.

1982-05-04

Normally solid dissolved coal product and a distillate liquid product are produced by continuously passing a feed slurry comprising raw feed coal and a recycle solvent oil and/or slurry together with hydrogen to a preheating-reaction zone (26, alone, or 26 together with 42), the hydrogen pressure in the preheating-reaction zone being at least 1500 psig (105 kg/cm.sup.2), reacting the slurry in the preheating-reaction zone (26, or 26 with 42) at a temperature in the range of between about 455.degree. and about 500.degree. C. to dissolve the coal to form normally liquid coal and normally solid dissolved coal. A total slurry residence time is maintained in the reaction zone ranging from a finite value from about 0 to about 0.2 hour, and reaction effluent is continuously and directly contacted with a quenching fluid (40, 68) to substantially immediately reduce the temperature of the reaction effluent to below 425.degree. C. to substantially inhibit polymerization so that the yield of insoluble organic matter comprises less than 9 weight percent of said feed coal on a moisture-free basis. The reaction is performed under conditions of temperature, hydrogen pressure and residence time such that the quantity of distillate liquid boiling within the range C.sub.5 -455.degree. C. is an amount at least equal to that obtainable by performing the process under the same conditions except for a longer total slurry residence time, e.g., 0.3 hour. Solvent boiling range liquid is separated from the reaction effluent and recycled as process solvent.

Caveats when Analyzing Ultra-high Molar Mass Polymers by SEC

USDA-ARS?s Scientific Manuscript database

The analysis of ultra-high molar mass (M > 1 million g/mol) polymers via size-exclusion chromatography (SEC) presents a number of non-trivial challenges. Dissolution and full solvation may take days, as is the case for cellulose dissolution in non-complexing non degrading solvents; very low concent...

Liquid Salt as Green Solvent: A Novel Eco-Friendly Technique to Enhance Solubility and Stability of Poorly Soluble Drugs

NASA Astrophysics Data System (ADS)

Patel, Anant A.

As a result of tremendous efforts in past few decades, various techniques have been developed in order to resolve solubility issues associated with class II and IV drugs, However, majority of these techniques offer benefits associated with certain drawbacks; majorly including low drug loading, physical instability on storage and excessive use of environmentally challenging organic solvents. Hence, current effort was to develop an eco-friendly technique using liquid salt as green solvent, which can offer improvement in dissolution while maintaining long term stability. The liquid salt formulations (LSF) of poorly soluble model drugs ibuprofen, gemfibrozil and indomethacin were developed using 1-Ethyl-3-methylimidazolium ethyl sulfate (EMIM ES) as a non-toxic and environmentally friendly alternate to organic solvents. Liquid medications containing clear solutions of drug, EMIM ES and polysorbate 20, were adsorbed onto porous carrier Neusilin US2 to form free flowing powder. The LSF demonstrated greater rate and extent of dissolution compared to crystalline drugs. The dissolution data revealed that more than 80% drug release from LSF within 20 mins compared to less than 18% release from pure drugs. As high as 70% w/w liquid loading was achieved while maintaining good flowability and compressibility. In addition, the LSF samples exposed to high temperature and high humidity i.e. 40°C/80% RH for 8 weeks, demonstrated excellent physical stability without any signs of precipitation or crystallization. As most desirable form of administration is tablet, the developed liquid salt formulations were transformed into tablets using design of experiment approach by Design Expert Software. The tablet formulation composition and critical parameter were optimized using Box-Behnken Design. This innovative liquid salt formulation technique offered improvement in dissolution rate and extent as well as contributed to excellent physical stability on storage. Moreover, this formulation approach served as eco-friendly compelling alternate to conventional techniques involving organic solvents.

Modification of crystal habit of ibuprofen using the phase partition technique: effect of aerosil and tween 80 in binding solvent.

PubMed

Umprayn, K; Luengtummuen, A; Kitiyadisai, C; Pornpiputsakul, T

2001-11-01

A ternary diagram, representing the solubility of binding solvent (chloroform) in a mixture of ethanol and water, was constructed. For this study, the solvent mixture that gave the best ibuprofen pellets (IPs) was composed of chloroform.ethanol:water at a ratio of 1.5%:8%:90.5%. The suitable agitator speed, temperature, and mixing time were found to be 1,500 rpm, 25 degrees C +/- 2 degrees C, and 20 min, respectively. In addition, suitable stirring time when the phase partition process of IPs began was 15 min. IPs obtained from these conditions were small and round, approximately 1 mm; surface determination by scanning electron microscopy (SEM) indicated that the IPs were composed of drug microcrystals rearranged on the surface. For the dissolution, IPs showed lower drug release when compared with pure ibuprofen crystal (IC) (f2 analysis). An attempt to modify the dissolution property of IP by incorporating various concentrations of Aerosil and Tween 80 in the binding solvent was made. Microscopic appearance showed that both Aerosil and Tween 80 gave less spherical pellets when compared with the use of binding solvent alone. For both the Aerosil and Tween 80 employed, the results indicated a change in rearrangement of drug microcrystals and a change in crystal habit. However, Tween 80 gave more change of the crystallographic direction of drug microcrystals than Aerosil. In term of dissolution, the results showed that employing Tween 80 at 1.2% gave the highest drug release compared to the use of Aerosil and IC alone (f2 analysis). These pellets had a good flow property, as indicated by Carr's compressibility, flow rate, and angle of repose, and they can be compressed into a tablet, encapsulated by suitable polymer, or pulverized to obtain micronized crystals. In the case of compression into tablets, the dissolution profiles of these tablets compared with those of commercial product meet the USP 24 requirement (Q > or = 80% at 60 min).

The use of solvent extractions and solubility theory to discern hydrocarbon associations in coal, with application to the coal-supercritical CO2 system

USGS Publications Warehouse

Kolak, Jonathan J.; Burruss, Robert A.

2014-01-01

Samples of three high volatile bituminous coals were subjected to parallel sets of extractions involving solvents dichloromethane (DCM), carbon disulfide (CS2), and supercritical carbon dioxide (CO2) (40 °C, 100 bar) to study processes affecting coal–solvent interactions. Recoveries of perdeuterated surrogate compounds, n-hexadecane-d34 and four polycyclic aromatic hydrocarbons (PAHs), added as a spike prior to extraction, provided further insight into these processes. Soxhlet-DCM and Soxhlet-CS2 extractions yielded similar amounts of extractable organic matter (EOM) and distributions of individual hydrocarbons. Supercritical CO2 extractions (40 °C, 100 bar) yielded approximately an order of magnitude less EOM. Hydrocarbon distributions in supercritical CO2 extracts generally mimicked distributions from the other solvent extracts, albeit at lower concentrations. This disparity increased with increasing molecular weight of target hydrocarbons. Five- and six-ring ring PAHs generally were not detected and no asphaltenes were recovered in supercritical CO2 extractions conducted at 40 °C and 100 bar. Supercritical CO2 extraction at elevated temperature (115 °C) enhanced recovery of four-ring and five-ring PAHs, dibenzothiophene (DBT), and perdeuterated PAH surrogate compounds. These results are only partially explained through comparison with previous measurements of hydrocarbon solubility in supercritical CO2. Similarly, an evaluation of extraction results in conjunction with solubility theory (Hildebrand and Hansen solubility parameters) does not fully account for the hydrocarbon distributions observed among the solvent extracts. Coal composition (maceral content) did not appear to affect surrogate recovery during CS2 and DCM extractions but might affect supercritical CO2 extractions, which revealed substantive uptake (partitioning) of PAH surrogates into the coal samples. This uptake was greatest in the sample (IN-1) with the highest vitrinite content. These findings indicate that hydrocarbon solubility does not exert a strong influence on hydrocarbon behavior in the systems studied. Other factors such as coal composition and maceral content, surface processes (physisorption), or other molecular interactions appear to affect the partitioning of hydrocarbons within the coal–supercritical CO2 system. Resolving the extent to which these factors might affect hydrocarbon behavior under different geological settings is important to efforts seeking to model petroleum generation, fractionation and expulsion from coal beds and to delineate potential hydrocarbon fate and transport in geologic CO2 sequestration settings.

Interaction and the structures of coal

NASA Astrophysics Data System (ADS)

Opaprakasit, Pakorn

The origin of a decrease in the amount of soluble material from coal upon a reflux treatment has been investigated in an attempt to obtain insight into the nature of the interaction in the macromolecular network structure of coal. This decrease in the extractable material is a result of an increase in the amount of physical cross-links associated with secondary interactions. The alternate possibility of covalent cross-link formation by ether linkage was found to be unlikely because the coal hydroxyl content remains unchanged upon heat treatment. The functional groups responsible for forming these physical cross-links and their contents vary from coal to coal with coal rank. Carboxylate/cation complexes, similar to those found in ionomers, dominate in low rank coal. In high rank coal, the clusters involving pi-cation interactions were observed. Both mechanisms seem to play a role in mid rank coals. These physical cross-links are responsible for a lowering of the extraction yield of coal, but are disrupted by a treatment with acid solution, resulting in an increase in the extraction yield. As a consequence, the cross-links in coal structure should be classified into two types; a "permanent" covalent cross-link, which break under extreme conditions such as chemical reaction and pyrolysis, and "reversible" cross-links, largely associated with ionomer-like structure and pi-cation interactions. The interaction between a "magic" solvent of N-methylpyrollidone and carbon disulfide (NMP/CS2) and its role in the unusual extractability enhancement of Upper Freeport coal has also been investigated. The results strongly suggest that NMP/CS2 mixed solvents form complexes with cations. These mixed solvents are capable of forming a solid complex with cations from NaOH and some simple salts, such as NaCl and LiCl. Given that Upper Freeport coal contains a large amount of mineral matter, it is not surprising that these types of complexes could be formed in the present of the mixed solvents, which in turn enhances the coal extraction yield. Finally, the evidence for the presence of a glass transition temperature in coal was examined. The results from Differential Scanning Calorimetry showed that no transition similar to the Tg can be observed in bulk coal or its low-molecular weight fraction, pyridine soluble extracted material, at a temperature near 110°C. In contrast, an irreversible transition that is due to water evaporation has been found. Thermomechanical measurements, which are very sensitive to the presence of a Tg in synthetic polymers, also provided no evidence for a Tg below temperatures where chemical reactions occur. Additionally, the results from Thermomechanical Analysis showed an expansion in size when the coal was heated to 300°C, which is associated with a "caking" process. The degree of expansion during this "caking" process is about five times greater in the direction perpendicular to the bedding plane than the parallel, indicating an accommodation of anisotropic strain relaxation, which was generated in the direction perpendicular to the bedding plane during the coalification process.

Direct use of methane in coal liquefaction

DOEpatents

Sundaram, Muthu S.; Steinberg, Meyer

1987-01-01

This invention relates to a process for converting solid carbonaceous material, such as coal, to liquid and gaseous hydrocarbons utilizing methane, generally at a residence time of about 20-120 minutes at a temperature of 250.degree.-750.degree. C., preferably 350.degree.-450.degree. C., pressurized up to 6000 psi, and preferably in the 1000-2500 psi range, preferably directly utilizing methane 50-100% by volume in a mix of methane and hydrogen. A hydrogen donor solvent or liquid vehicle such as tetralin, tetrahydroquinoline, piperidine, and pyrolidine may be used in a slurry mix where the solvent feed is 0-100% by weight of the coal or carbonaceous feed. Carbonaceous feed material can either be natural, such as coal, wood, oil shale, petroleum, tar sands, etc., or man-made residual oils, tars, and heavy hydrocarbon residues from other processing systems.

Enhancement of ibuprofen dissolution via wet granulation with beta-cyclodextrin.

PubMed

Ghorab, M K; Adeyeye, M C

2001-08-01

The purpose was to investigate the effect of wet granulation with beta-cyclodextrin (betaCD) on the enhancement of ibuprofen (IBU) dissolution. The effect of the granulation variables on the physical properties as well as the dissolution of tablets prepared from these granules was also examined. Granulation was performed using three granulating solvents: water, ethanol (95 vol%), and isopropanol. Granules were either oven-dried for 2 h or air-dried for 3 days. The granules or respective physical mixtures were compressed into tablets. Powder X-ray diffraction showed that oven-dried granulation resulted in less amorphous entities thatfacilitated IBU-betaCD complexation in solution and enhanced the dissolution of the corresponding tablets compared to the physical mixture with or without oven drying. In contrast, air-dried granulation did not cause any differences in the X-ray diffraction pattern (crystallinity) or the dissolution compared to the physical mixture without drying. Isopropanol and water, as granulating solvents, enhanced the dissolution of the oven-dried batches more than ethanol. The Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) data showed that tablets prepared from oven-dried granules, but not air-dried granules, had lower AH values and percent loss in weight, respectively, than those prepared from the physical mixture as a result of the expulsion of the water molecules from the betaCD cavity and enhancement of the complexation in solution. These results showed that oven-dried granulation of IBU and betaCD provided faster IBU dissolution than the physical mixture; air-dried granulation did not substantially affect the dissolution of IBU.

Solubilization of coal in organic media

NASA Technical Reports Server (NTRS)

Lahaye, P.; Decroocq, D.

1977-01-01

The use of solvent extraction to solubilize coal is discussed. Simple extractions are described which are conducted at moderate temperatures to exclude extraneous chemical reactions which would lead to uncontrolled changes in the components of the treated coal. Sample preparation, extraction apparatus, and the determination of extract yield for different experiments are also described.

Improvement of solubility, dissolution and stability profile of artemether solid dispersions and self emulsified solid dispersions by solvent evaporation method.

PubMed

Tayyab Ansari, Muhammad; Arshad, Muhammad Sohail; Hussain, Altaf; Ahmad, Zeeshan

2016-12-08

The purpose of this study was to investigate changes in the water solubility of artemether; a poorly soluble drug used for the treatment of malaria. Different solid dispersions (SDs) of artemether were prepared using artemether and polyethylene glycol 6000 at ratio 12:88 (Group 1), self-emulsified solid dispersions (SESDs) containing artemether, polyethylene glycol 6000, cremophor-A-25, olive oil, hydroxypropylmethylcellulose and transcutol in the ratio 12:75:5:4:2:2, respectively (Group 2). SESDs were also prepared by substituting cremophor-A-25 in Group 2 with poloxamer 188 (noted as Group 3). Each of these preparations was formulated using physical mixing and the solvent evaporation method. Aqueous solubility of artemether improved 11-, 95- and 102-fold, while dissolution (in simulated gastric fluid) increased 3-, 13- and 14-fold, for formulation groups 1, 2 and 3, respectively. X-ray diffraction patterns of SDs indicated a decrease in peak intensities at 10° implying reduced artemether crystallinity. Scanning electron micrographs invariably revealed embedment of artemether by various excipients and a glassy appearance for solvent evaporated mixtures for all three formulation Groups. Our findings indicate improved hydrophilic interactions for drug particles yield greater solubility and dissolution in the following order for artemether formulating methods: solvent evaporation mixtures > physical mixtures > pure artemether.

Integration of advanced preparation with coal liquefaction. Second quarterly technical progress report, January 1-March 31, 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steedman, W.G.; Longanbach, J.R.; Muralidhara, H.S.

Standard reaction conditions of 427 C, 5 minutes reaction time, 2:1 solvent/coal ratio and 1000 psig (r.t.) hydrogen overpressure result in good, but not maximum, conversions to THF soluble with both Illinois No. 6 and Wyodak (upper seam) coals. The cumulative effects of the pretreatment steps were also examined using feedstocks which were dried in a vacuum oven at room temperature under nitrogen before liquefaction to remove the effects of moisture. Chloride removal followed by drying had a positive effect on liquefaction. Oil agglomeration followed by drying also improved liquefaction reactivity significantly. Solvent drying also resulted in a small increasemore » in liquefaction reactivity. The overall reactivity of coal treated in sequence with each pretreatment step was slightly less than that of the dry ground coal. Liquefaction under a high partial pressure of hydrogen sulfide in hydrogen also results in a significant increase in conversion to THF solubles. 1 reference, 12 figures, 7 tables.« less

Factors that influence the extraction of polycyclic aromatic hydrocarbons from coal

USGS Publications Warehouse

Xue, J.; Liu, Gaisheng; Niu, Z.; Chou, C.-L.; Qi, C.; Zheng, Lingyun; Zhang, H.

2007-01-01

Coal samples and carbonaceous mudstone were collected from the Huaibei coalfield, China, and experiments investigating the factors influencing the extraction of the sixteen US EPA (Environmental Protection Agency) priority polycyclic aromatic hydrocarbons (PAHs) were carried out. Different extraction times, solvents, and methods were used. Major interest was focused on finding optimum conditions for extracting the PAHs from coal. We conclude that (1) coal composition, including the H/C and O/C ratios, is an important factor for the distribution of PAHs in coals; (2) the total amount of EPA priority PAHs increases with increasing extraction time, 30 min being suitable for ultrasonic-assisted extraction and 24 h for Soxhlet extraction; (3) CS2 is effective in extracting low molecular weight PAHs, while CH2Cl2 is better for extracting high molecular weight PAHs (both are excellent extraction solvents vs hexane); (4) both Soxhlet and ultrasonic extraction showed a similar PAH concentration profile, but the ultrasonic method is less efficient. ?? 2007 American Chemical Society.

DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliot B. Kennel; Stephen P. Carpenter; Dady Dadyburjor

2006-03-27

The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. During this reporting period, efforts have focused on the development of continuous processes for hydrogenation as well as continuous production of carbon foam and coke.

The SRC-II process

NASA Astrophysics Data System (ADS)

Schmid, B. K.; Jackson, D. M.

1981-03-01

The Solvent Refined Coal (SRC-II) process which produces low-sulfur distillate fuel oil from coal is discussed. The process dissolves coal in a process-derived solvent at elevated temperature and pressure in the presence of hydrogen, separates the undissolved mineral residue, then recovers the original solvent by vacuum distillation. The distillate fuel oil produced is for use largely as a nonpolluting fuel for generating electrical power and steam and is expected to be competitive with petroleum fuels during the 1980s. During this period, the SRC-II fuel oil is expected to be attractive compared with combustion of coal with flue gas desulfurization in U.S. East Coast oil-burning power plants, as well as in small and medium-sized industrial boilers. The substantial quantities of methane, light hydrocarbons and naphtha produced by the process have value as feedstocks for preparation of pipeline gas, ethylene and high-octane unleaded gasoline, and can replace petroleum fractions in many applications. The liquid and gas products from a future large-scale plant, such as the 6000 t/day plant planned for Morgantown, West Virginia, are expected to have an overall selling price of $4.25 to $4.75/GJ.

Understanding cellulose dissolution: energetics of interactions of ionic liquids and cellobiose revealed by solution microcalorimetry.

PubMed

de Oliveira, Heitor Fernando Nunes; Rinaldi, Roberto

2015-05-11

In this report, the interactions between fifteen selected ionic liquids (ILs) and cellobiose (CB) are examined by high-precision solution microcalorimetry. The heat of mixing (Δmix H) of CB and ILs, or CB and IL/molecular solvent (MS) solutions, provides the first ever-published measure of the affinity of CB with ILs. Most importantly, we found that there is a very good correlation between the nature of the results found for Δmix H(CB) and the solubility behavior of cellulose. This correlation suggests that Δmix H(CB) offers a good estimate of the enthalpy of dissolution of cellulose even in solvents in which cellulose is insoluble. Therefore, the current findings open up new horizons for unravelling the intricacies of the thermodynamic factors accounting for the spontaneity of cellulose dissolution in ILs or IL/MS solutions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Applications of micellar enzymology to clean coal technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, C.T.

1990-10-26

This project is designed to develop methods for pre-combustion coal remediation by implementing recent advances in enzyme biochemistry. The novel approach of this study is incorporation of hydrophilic oxidative enzymes in reverse micelles in an organic solvent. Enzymes from commercial sources or microbial extracts are being investigated for their capacity to remove organic sulfur from coal by oxidation of the sulfur groups, splitting of C-S bonds and loss of sulfur as sulfuric acid Dibenzothiophene (DBT) and ethlyphenylsulfide (EPS) are serving as models of organic sulfur-containing components of coal in initial studies. A goal of this project is to define amore » reverse micelle system that optimizes the catalytic activity of enzymes toward desulfurization of model compounds and ultimately coal samples. Among the variables which will be examined are the surfactant, the solvent, the water:surfactant ration and the pH and ionic strength of the aqueous phase. Studies were carried out with HRP, Type I RZ=1.2 and Type VI RZ=3.2 and laccase from Polyporus versicolor. Substrates for HRP assays included hydrogen peroxide, DBT, DBT sulfoxide, and DBT sulfone. Buffers included sodium phosphate. For formation of reverse micelle solutions the surfactant AOT, di(2-ethyl-hexyl)sodium sulphosuccinate, was obtained from Sigma Chemical Co. Isooctant was used as organic solvent. 12 refs., 5 figs., 3 tabs.« less

Operation of the solvent-refined-coal pilot plant, Wilsonville, Alabama. Annual technical report, January-December 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, H.E.

1981-08-01

The plant was in operation for the equivalent of 247 days, an on-stream factor of 67.7%. Kentucky 9 coals from the Lafayette, Dotiki and Fies mines were processed. During 1980, the operating conditions and equipment were adjusted to evaluate potential process improvements. These experiments produced significant results in the following areas: Operating V103 High Pressure Separator in the hot mode; varying T102 Vacuum Column operating temperature; adding light SRC (LSRC), a product of the third stage of the Critical Solvent Deashing (CSD) unit, to the process solvent; investigating the effects of the chlorine content of the feed coal on corrosionmore » in the process vessels; evaluating the effects of adding sodium carbonate on corrosion rates; operating under conditions of low severity; i.e., low reactor temperature and long residence time; and testing an alternate CSD deashing solvent. A series of simulation runs investigating the design operating conditions for a planned 6000 ton per day SRC-I demonstation plant were also completed. Numerous improvements were made in the CSD processing area, and the components for a hydrotreating unit were installed.« less

Hydrogen Transfer during Liquefaction of Elbistan Lignite to Biomass; Total Reaction Transformation Approach

NASA Astrophysics Data System (ADS)

Koyunoglu, Cemil; Karaca, Hüseyin

2017-12-01

Given the high cost of the tetraline solvent commonly used in liquefaction, the use of manure with EL is an important factor when considering the high cost of using tetraline as a hydrogen transfer source. In addition, due to the another cost factor which is the catalyst prices, red mud (commonly used, produced as a byproduct in the production of aluminium) is reduced cost in the work of liquefaction of coal, biomass, even coal combined biomass, corresponding that making the EL liquefaction an agenda for our country is another important factor. Conditions for liquefaction experiments conducted for hydrogen transfer from manure to coal; Catalyst concentration of 9%, liquid/solid ratio of 3/1, reaction time of 60 min, fertilizer/lignite ratio of 1/3, and the reaction temperature of 400 °C, the stirred speed of 400 rpm and the initial nitrogen pressure of 20 bar was fixed. In order to demonstrate the hydrogen, transfer from manure to coal, coal is used solely, by using tetraline (also known as a hydrogen carrier) and distilled water which is not hydrogen donor as a solvent in the co-liquefaction of experiments, and also the liquefaction conditions are carried out under an inert (N2) gas atmosphere. According to the results of the obtained liquefaction test; using tetraline solvent the total liquid product conversion percentage of the oil + gas conversion was 38.3 %, however, the results of oil+gas conversion obtained using distilled water and EL combined with manure the total liquid product conversion percentage was 7.4 %. According to the results of calorific value and elemental analysis, only the ratio of (H/C)atomic of coal obtained by using tetraline increased with the liquefaction of manure and distilled water. The reason of the increase in the amount of hydrogen due to hydrogen transfer from the manure on the solid surface of the coal, and also on the surface of the inner pore of the coal during the liquefaction, brings about the evaluation of the coal as a structure involved in the recycling through the liquefaction plant if it is being installed. As a result of this study, results obtained from oil + gas data shows that when distilled water is used instead of tetraline during liquefaction of EL combined with manure, abundant crude hydrogen transfer takes place not because of using distilled water as a solvent but only with manure considered as a hydrogen sources. Furthermore, while adding manure into coal of liquefaction is also an alternative for current oil production.

Solid dispersion of dutasteride using the solvent evaporation method: Approaches to improve dissolution rate and oral bioavailability in rats.

PubMed

Choi, Jin-Seok; Lee, Sang-Eun; Jang, Woo Suk; Byeon, Jong Chan; Park, Jeong-Sook

2018-09-01

The aim of this study was to develop a dutasteride (DUT) solid dispersion (SD) using hydrophilic substances to enhance its dissolution (%) and oral bioavailability in rats. DUT-SD formulations were prepared with various co-polymers using a solvent evaporation method. The physical properties of DUT-SD formulations were confirmed using field emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. The toxicity and oral bioavailability of DUT-SD formulations were evaluated. Tocopheryl polyethylene glycol-1000-succinate (TPGS) was chosen as the solubilizer; and methylene chloride, and Aerosil® 200 or microcrystalline cellulose (MCC) were chosen as the solvent and carrier, respectively, based on a solubility test and pre-dissolution study. The dissolution levels of DUT-SD formulations were 86.3 ± 2.3% (F15) and 95.1 ± 1.9% (F16) after 1 h, which were higher than those of the commercial product, i.e., Avodart® (75.8 ± 1.5%) in 0.1 N HCl containing 1% (w/v) sodium lauryl sulfate (SLS). The F16 formulation was found to be stable, after assessing its dissolution (%) and drug content (%) for 6 months. The DUT-SD formulations resulted in relative bioavailability (BA) values of 126.4% (F15) and 132.1% (F16), which were enhanced compared to that of Avodart®. Dissolution (%) and relative BA values were both increased by hydrogen interaction between TPGS and DUT. This study might contribute to a new formulation (powder) whose oral bioavailability is greater than that of Avodart® (soft capsule), which could facilitate to the use of the SD system during the production process. Copyright © 2018 Elsevier B.V. All rights reserved.

Continuous process for conversion of coal

DOEpatents

Knudson, Curtis L.; Willson, Warrack G.; Baker, Gene G.; Sondreal, Everett A.; Farnum, Sylvia A.

1982-01-01

An improved process for converting coal to liquid and gaseous products wherein the liquid products predominate and wherein reactor, tubing, and valve plugging due to carbonate salt formation is reduced by reacting crushed low-rank coal containing about 12 to 30% by weight of water in a solvent at a temperature in the range of about 455.degree. to 500.degree. C., under about 2000 to 5000 psi pressure of a H.sub.2 /CO mixture for a liquid residence time of about 20 to 60 minutes. The solvent is a fraction of liquid product defined on a weight basis as being made up of about 55% of which distills at less than 250.degree. C./lmm, about 20% of which is soluble in THF, and about 25% of which is carbon polymer and indigenous inorganic matter. The solvent is further defined as containing at least about 5 weight % of partially hydrogenated aromatics and/or fully hydrogenated aromatics and little or no alkylated aromatics or higher alkanes.

Catalytic coal hydroliquefaction process

DOEpatents

Garg, Diwakar

1984-01-01

A process is described for the liquefaction of coal in a hydrogen donor solvent in the presence of hydrogen and a co-catalyst combination of iron and a Group VI or Group VIII non-ferrous metal or compounds of the catalysts.

Direct use of methane in coal liquefaction

DOEpatents

Sundaram, M.S.; Steinberg, M.

1985-06-19

This invention relates to a process for converting solid carbonaceous material, such as coal, to liquid and gaseous hydrocarbons utilizing methane, generally at a residence time of about 20 to 120 minutes at a temperature of 250 to 750/sup 0/C, preferably 350 to 450/sup 0/C, pressurized up to 6000 psi, and preferably in the 1000 to 2500 psi range, preferably directly utilizing methane 50 to 100% by volume in a mix of methane and hydrogen. A hydrogen donor solvent or liquid vehicle such as tetralin, tetrahydroquinoline, piperidine, and pyrolidine may be used in a slurry mix where the solvent feed is 0 to 100% by weight of the coal or carbonaceous feed. Carbonaceous feed material can either be natural, such as coal, wood, oil shale, petroleum, tar sands, etc., or man-made residual oils, tars, and heavy hydrocarbon residues from other processing systems. 1 fig.

Cocrystal habit engineering to improve drug dissolution and alter derived powder properties.

PubMed

Serrano, Dolores R; O'Connell, Peter; Paluch, Krzysztof J; Walsh, David; Healy, Anne Marie

2016-05-01

Cocrystallization of sulfadimidine (SDM) with suitable coformers, such as 4-aminosalicylic acid (4-ASA), combined with changes in the crystal habit can favourably alter its physicochemical properties. The aim of this work was to engineer SDM : 4-ASA cocrystals with different habits to investigate the effect on dissolution, and the derived powder properties of flow and compaction. Cocrystals were prepared in a 1 : 1 molar ratio by solvent evaporation using ethanol (habit I) or acetone (habit II), solvent evaporation followed by grinding (habit III) and spray drying (habit IV). Powder X-ray diffraction showed Bragg peak position was the same in all the solid products. The peak intensity varied, indicating different preferred crystal orientation confirmed by SEM micrographs: large prismatic crystals (habit I), large plate-like crystals (habit II), small cube-like crystals (habit III) and microspheres (habit IV). The habit III exhibited the fasted dissolution rate; however, it underwent a polymorphic transition during dissolution. Habits I and IV exhibited the highest Carr's compressibility index, indicating poor flowability. However, habits II and III demonstrated improved flow. Spray drying resulted in cocrystals with improved compaction properties. Even for cocrystals with poor pharmaceutical characteristics, a habit can be engineered to alter the dissolution, flowability and compaction behaviour. © 2015 Royal Pharmaceutical Society.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elmore, B.B.

As an alternative to post-combustion desulfurization of coal and pre-combustion desulfurization using physicochemical techniques, the microbial desulfurization of coal may be accomplished through the use of microbial cultures that, in an application of various microbial species, may remove both the pyritic and organic fractions of sulfur found in coal. Organisms have been isolated that readily depyritize coal but often at prohibitively low rates of desulfurization. Microbes have also been isolated that may potentially remove the organic-sulfur fraction present in coal (showing promise when acting on organic sulfur model compounds such as dibenzothiophene). The isolation and study of microorganisms demonstrating amore » potential for removing organic sulfur from coal has been undertaken in this project. Additionally, the organisms and mechanisms by which coal is microbially depyritized has been investigated. Three cultures were isolated that grew on dibenzothiophene (DBT), a model organic-sulfur compound, as the sole sulfur source. These cultures (UMX3, UMX9, and IGTS8) also grew on coal samples as the sole sulfur source. Numerous techniques for pretreating and ``cotreating`` coal for depyritization were also evaluated for the ability to improve the rate or extent of microbial depyritization. These include prewashing the coal with various solvents and adding surfactants to the culture broth. Using a bituminous coal containing 0.61% (w/w) pyrite washed with organic solvents at low slurry concentrations (2% w/v), the extent of depyritization was increased approximately 25% in two weeks as compared to controls. At slurry concentrations of 20% w/v, a tetrachloroethylene treatment of the coal followed by depyritization with Thiobacillus ferrooxidans increased both the rate and extent of depyritization by approximately 10%.« less

PAH in the laboratory and interstellar space

NASA Technical Reports Server (NTRS)

Wdowiak, Thomas J.; Flickinger, Gregory C.; Boyd, David A.

1989-01-01

The theory that polycyclic aromatic hydrocarbons (PAHs) are a constituent of the interstellar medium, and a source of the IR emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3 microns is being studied using PAH containing acid insoluble residue of the Orgueil CI meteorite and coal tar. FTIR spectra of Orgueil PAH material that has undergone thermal treatment, and a solvent insoluble fraction of coal tar that has been exposed to hydrogen plasma are presented. The UV excided luminescence spectrum of a solvent soluble coal tar film is also shown. Comparison of the lab measurements with observations appears to support the interstellar PAH theory, and shows the process of dehydrogenation expected to take place in the interstellar medium.

Thermochemistry of C60 fullerene solutions in benzene, toluene, o-xylene, and o-dichlorobenzene at 298.15 K

NASA Astrophysics Data System (ADS)

Akhapkina, T. E.; Krusheva, M. A.; Solov'ev, S. N.; Firer, A. A.

2017-02-01

The enthalpies of dissolution of C60 in benzene, toluene, o-xylene and o-dichlorobenzene are measured in a sealed high-sensitivity calorimeter at 298.15 K and at different concentrations of the solute. The standard enthalpies of dissolution of C60 in these solvents are determined.

Enhancement of Loperamide Dissolution Rate by Liquisolid Compact Technique.

PubMed

Venkateswarlu, Kambham; Preethi, Jami Komala; Chandrasekhar, Kothapalli Bonnoth

2016-09-01

Purpose: The aim of present study was to improve the dissolution rate of poorly soluble drug Loperamide (LPM) by liquisolid compact technique. Methods: Liquisolid compacts of LPM were prepared using Propylene glycol (PG) as a solvent, Avicel pH 102 as carrier, Aerosil as coating material and Sodium Starch Glycolate (SSG) as superdisintegrant. Interactions between the drug and excipients were examined by Fourier Transform Infrared (FTIR) spectroscopy. The dissolution studies for LPM liquisolid formulation, marketed product and pure drug were carried out in pH 1.2 HCl buffer as dissolution media. Results: Results confirmed the absence of chemical interactions between the drug and excipients. From the solubility studies, it was observed the LPM was highly soluble in PG thereby it was selected as a solvent. The dissolution efficiency of LPM at 15 min was increased from 9.99 % for pure drug and 54.57% for marketed product to 86.81% for the tablets prepared by liquisolid compact technique. Stability studies showed no significant change in percent cumulative drug release, hardness, disintegration time, friability and drug content for 3 months. Conclusion: Formulation F2 showed significant increase in dissolution rate compared to the marketed product at pH 1.2 where LPM is largely absorbed. Around 90% of the drug was released from F2 in 30 min compared to the marketed product and it might be due to the increased wetting and surface area of the particles. Hence, the liquisolid compact technique appears to be a promising approach for improving the dissolution rate of poorly soluble drug.

Thermodynamics of cellulose solvation in water and the ionic liquid 1-butyl-3-methylimidazolim chloride.

PubMed

Gross, Adam S; Bell, Alexis T; Chu, Jhih-Wei

2011-11-24

Cellulose is present in biomass as crystalline microfibrils held together by a complex network of intermolecular interactions making it difficult to initiate its hydrolysis and conversion to fuels. While cellulose is insoluble in water and most organic solvents, complete dissolution of cellulose can be achieved in certain classes of ionic liquids (ILs). The present study was undertaken to analyze the thermodynamic driving forces of this process and to understand how the anions and cations comprising an IL interact with the different moieties of glucose residues to cause dissolution. All-atom molecular dynamics (MD) simulations were performed at two extreme states of cellulose dissolution: a crystalline microfibril and a dissociated state in which all the glucan chains of the microfibril are fully separated from each other by at least four solvation shells. MD simulations of the two states were carried out in water and in the IL 1-butyl-3-methylimidazolium chloride (BmimCl) to provide a comprehensive analysis of solvent effects on cellulose dissolution. The results reveal two important molecular aspects of the mechanism of cellulose dissolution. The first is that the perturbation of solvent structures by the dissolved glucan chains can be a crucial factor in determining solubility, particularly for the insolubility of cellulose in water at 300 K. Second, both the Cl(-) and the Bmim(+) ions of BmimCl interact with the moieties of glucan residues that form intersheet contacts, the most robust component of the interaction network of crystalline cellulose. Cl(-) anions can form hydrogen bonds (HBs) with the hydroxyl groups of glucan chains from either the equatorial or the axial directions. For Bmim(+) cations, the calculated density profiles reveal that the contacts with glucan chains along the axial directions are closer than those along the equatorial directions. On the basis of the results of atomistic MD simulations, we propose that interacting with glucan chains along axial directions and disrupting the intersheet contacts of cellulose is an important ability of cellulose pretreatment solvents. © 2011 American Chemical Society

Pretreatment of Lignocellulosic Biomass with Ionic Liquids and Ionic Liquid-Based Solvent Systems.

PubMed

Hou, Qidong; Ju, Meiting; Li, Weizun; Liu, Le; Chen, Yu; Yang, Qian

2017-03-20

Pretreatment is very important for the efficient production of value-added products from lignocellulosic biomass. However, traditional pretreatment methods have several disadvantages, including low efficiency and high pollution. This article gives an overview on the applications of ionic liquids (ILs) and IL-based solvent systems in the pretreatment of lignocellulosic biomass. It is divided into three parts: the first deals with the dissolution of biomass in ILs and IL-based solvent systems; the second focuses on the fractionation of biomass using ILs and IL-based solvent systems as solvents; the third emphasizes the enzymatic saccharification of biomass after pretreatment with ILs and IL-based solvent systems.

Studies of coupled chemical and catalytic coal conversion methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stock, L.M.

1988-01-01

Liquefaction of coal by depolymerization in an organic solvent has been studied for several years. The liquefied coal extract which results from such a process is far more suitable for conversion into liquid fuel by hydrogenolysis than is the untreated coal. Investigations on the chemical structure and the reactive sites of coal can help to select useful reactions for the production of liquids from coal. Sternberg et al. demonstrated that the reductive alkylation method transforms bituminous coal into an enormously soluble substance, irrespective of the mild reaction conditions. The effectiveness of newly introduced alkyl groups for the disruption of intermolecularmore » hydrogen bonds and pi-pi interactions between the aromatic sheets in coal macromolecules has been recognized. It has been reported by Ignasiak et al. that a C-alkylabon reaction using sodium or potassium amide in liquid ammonia can be used to introduce alkyl groups at acidic carbon sites. A method has been developed recently in this laboratory for the solubilization of high rank coals. In the previous reports it was shown that n-butyl lithium and potassium t-butoxide in refluxing heptane produced coal anions which could be alkylated with different alkyl halides. Such alkylated coals were soluble up to 92% in solvents like pyridine. Though the solubilization of coal depended very much on the length of the alkyl group, it also depended very much on the nature of the base used. Strong bases like n-butyl lithium (pKa=42) can cause proton abstraction from aromatic structures, if the more acidic benzylic protons are absent. The utility of this procedure, initially developed and used by Miyake and Stock, has now been tested with the high oxygen containing, low rank Illinois No. 6 and Wyodak coals.« less

Studies of coupled chemical and catalytic coal conversion methods. Fifth quarterly report, October--December 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stock, L.M.

1988-12-31

Liquefaction of coal by depolymerization in an organic solvent has been studied for several years. The liquefied coal extract which results from such a process is far more suitable for conversion into liquid fuel by hydrogenolysis than is the untreated coal. Investigations on the chemical structure and the reactive sites of coal can help to select useful reactions for the production of liquids from coal. Sternberg et al. demonstrated that the reductive alkylation method transforms bituminous coal into an enormously soluble substance, irrespective of the mild reaction conditions. The effectiveness of newly introduced alkyl groups for the disruption of intermolecularmore » hydrogen bonds and pi-pi interactions between the aromatic sheets in coal macromolecules has been recognized. It has been reported by Ignasiak et al. that a C-alkylabon reaction using sodium or potassium amide in liquid ammonia can be used to introduce alkyl groups at acidic carbon sites. A method has been developed recently in this laboratory for the solubilization of high rank coals. In the previous reports it was shown that n-butyl lithium and potassium t-butoxide in refluxing heptane produced coal anions which could be alkylated with different alkyl halides. Such alkylated coals were soluble up to 92% in solvents like pyridine. Though the solubilization of coal depended very much on the length of the alkyl group, it also depended very much on the nature of the base used. Strong bases like n-butyl lithium (pKa=42) can cause proton abstraction from aromatic structures, if the more acidic benzylic protons are absent. The utility of this procedure, initially developed and used by Miyake and Stock, has now been tested with the high oxygen containing, low rank Illinois No. 6 and Wyodak coals.« less

INTERACTION OF PLANAR AND NONPLANAR ORGANIC CONTAMINANTS WITH COAL FLY ASH: EFFECTS OF POLAR AND NONPOLAR SOLVENT SOLUTIONS

EPA Science Inventory

Coal fly ash has several uses but much of the material is treated as waste and disposed of in various ways including land filling. Coal fly ash also has a very high sorption capacity for a variety of anthropogenic contaminants and has been used to cleanse wastewater of such poll...

Influence of carboxyl anion on the dissolution of chitosan in cholinium-based ionic liquids

NASA Astrophysics Data System (ADS)

Liu, Dong; Chen, Qingtai; Li, Min; Lou, Bin; Yu, Ran; Li, Zhiheng; Zhang, Yadong

2018-06-01

Chitosan can be applied in because of its excellent antimicrobial activity and abundant bio renewable and biodegradable resource. To better utilize this kind of native polysaccharide, it is still necessary to develop an efficient chitosan solvent system. Tn present study, 6 kinds of novel choline carboxylate ionic liquids (ILs) were developed. The solubility of chitosan in these H2O-ILs with different molar ratio were measured at 25 °C. The effect of the carboxylate anion of the ILs on chitosan solubility was estimated and found that the solubility of chitosan in the H2O-IL increased with the increasing of alkyl chain length in the anion. Moreover, the H2O-IL solution would not able to dissolve chitosan because the proton H was alternated by employing NH2 or OH group. The H2O-[Ch][CH3CH2CH2COO] (Rmol=6:1) solvent system exhibits highly efficient capacity for the dissolution of chitosan, and the solubility of chitosan reached up to 20.8 wt.%. From NMR measurement, these results could be explained by the possible interaction between carboxylate anion and chitosan and the strong hydration of the carboxyl group in the IL, suggesting that anionic structure have a significant impact on the dissolution of chitosan in the H2O-IL solvent system. Altogether, these results would provide an important evaluation indicator for screening the most suitable solvent system of chitosan.

Coal liquefaction process with increased naphtha yields

DOEpatents

Ryan, Daniel F.

1986-01-01

An improved process for liquefying solid carbonaceous materials wherein the solid carbonaceous material is slurried with a suitable solvent and then subjected to liquefaction at elevated temperature and pressure to produce a normally gaseous product, a normally liquid product and a normally solid product. The normally liquid product is further separated into a naphtha boiling range product, a solvent boiling range product and a vacuum gas-oil boiling range product. At least a portion of the solvent boiling-range product and the vacuum gas-oil boiling range product are then combined and passed to a hydrotreater where the mixture is hydrotreated at relatively severe hydrotreating conditions and the liquid product from the hydrotreater then passed to a catalytic cracker. In the catalytic cracker, the hydrotreater effluent is converted partially to a naphtha boiling range product and to a solvent boiling range product. The naphtha boiling range product is added to the naphtha boiling range product from coal liquefaction to thereby significantly increase the production of naphtha boiling range materials. At least a portion of the solvent boiling range product, on the other hand, is separately hydrogenated and used as solvent for the liquefaction. Use of this material as at least a portion of the solvent significantly reduces the amount of saturated materials in said solvent.

The Role of Residual Casting Solvent in Determining the Lithographic and Dissolution Behavior of Poly(methyl Methacrylate), a Positive Electron Beam Resist.

NASA Astrophysics Data System (ADS)

Criss, Robert Randolph, Jr.

The effect of the pre-exposure bake and the choice of casting solvent on the sensitivity and contrast of PMMA has been documented to an extent not previously reported in the literature. PMMA films were spin cast onto clean silicon substrates from chlorobenzene and tri-chloroethylene solutions. The temperature of the pre-bake was varied over the range of 59^circ to 170^circC using a convection oven with pre-bake times ranging from 30 to 90 minutes. At the end of the designated bake time, the films were removed from the oven and allowed to cool in a temperature and humidity controlled environment. They were promptly exposed to a 15 KeV electron beam, then developed, with mild agitation, in a 1:1 mixture of MIBK and IPA at 22.5^ circC. Film thickness profiles were determined with an alpha-step profilometer. Films baked at temperatures below T_{rm glass} (the temperature which marks the onset of long-range, coordinated molecular motion), exhibited improved sensitivity and poorer contrast when compared to those baked above T_{rm glass }. Unique to this work is the finding that the lithographic performance depends on the choice of casting solvent, even at pre-bake temperatures significantly above T_{rm glass}. The relative concentrations of the casting solvents remaining in the baked films was determined from UV absorption spectra. The dissolution rates of exposed films were also measured and compared to the fragmented molecular weight model of development. Energy depositions were calculated from the empirical model of Everhart and Hoff. Cross-correlation of these results indicate that the pre-bake temperature more strongly correlates with the observed improvement in sensitivity than the presence of residual casting solvent. Residual casting solvent changes the density of the film, thus changing the energy deposition and dissolution behavior. Calculations based on the aforementioned models indicate that the observed lithographic and dissolution behavior can not be accounted for by this change in density. Arguments are presented to support the conclusion that the observed behavior is associated with film morphology. Comparison of results from films cast from TCE and chlorobenzene and baked above T_{rm glass} further support this conclusion.

Solubility and dissolution thermodynamics of phthalic anhydride in organic solvents at 283-313 K

NASA Astrophysics Data System (ADS)

Wang, Long; Zhang, Fang; Gao, Xiaoqiang; Luo, Tingliang; Xu, Li; Liu, Guoji

2017-08-01

The solubility of phthalic anhydride was measured at 283-313 K under atmospheric pressure in ethyl acetate, n-propyl acetate, methyl acetate, acetone, 1,4-dioxane, n-hexane, n-butyl acetate, cyclohexane, and dichloromethane. The solubility of phthalic anhydride in all solvents increased with the increasing temperature. The Van't Hoff equation, modified Apelblat equation, λ h equation, and Wilson model were used to correlate the experimental solubility data. The standard dissolution enthalpy, the standard entropy, and the standard Gibbs energy were evaluated based on the Van't Hoff analysis. The experimental data and model parameters would be useful for optimizing of the separation processes involving phthalic anhydride.

Triticonazole enantiomers: Separation by supercritical fluid chromatography and the effect of the chromatographic conditions.

PubMed

He, Jianfeng; Fan, Jun; Yan, Yilun; Chen, Xiaodong; Wang, Tai; Zhang, Yaomou; Zhang, Weiguang

2016-11-01

Enantiomeric pairs of triticonazole have been successfully separated by supercritical fluid chromatography coupled with a tris(3,5-dimethylphenylcarbamoyl) cellulose-coated chiral stationary phase in this work. The effects of co-solvent, dissolution solvent, flow rate, backpressure, and column temperature have been studied in detail with respect to retention, selectivity, and resolution of triticonazole. As indicated, the co-solvents mostly affected the retention factors and resolution, due to the different molecular structure and polarity. In addition, the dissolution solvents, namely, chloromethanes and alcohols, have been also important for enantioseparation because of the different interaction with stationary phase. Higher flow rate and backpressure led to faster elution of the triticonazole molecules, and the change of column temperature showed slight effect on the resolution of triticonazole racemate. Moreover, a comparative separation experiment between supercritical fluid chromatography and high performance liquid chromatography revealed that chiral supercritical fluid chromatography gave the 3.5 times value of R s /t R2 than high performance liquid chromatography, which demonstrated that supercritical fluid chromatography had much higher separation efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Process for coal liquefaction employing selective coal feed

DOEpatents

Hoover, David S.; Givens, Edwin N.

1983-01-01

An improved coal liquefaction process is provided whereby coal conversion is improved and yields of pentane soluble liquefaction products are increased. In this process, selected feed coal is pulverized and slurried with a process derived solvent, passed through a preheater and one or more dissolvers in the presence of hydrogen-rich gases at elevated temperatures and pressures, following which solids, including mineral ash and unconverted coal macerals, are separated from the condensed reactor effluent. The selected feed coals comprise washed coals having a substantial amount of mineral matter, preferably from about 25-75%, by weight, based upon run-of-mine coal, removed with at least 1.0% by weight of pyritic sulfur remaining and exhibiting vitrinite reflectance of less than about 0.70%.

Process for heating coal-oil slurries

DOEpatents

Braunlin, W.A.; Gorski, A.; Jaehnig, L.J.; Moskal, C.J.; Naylor, J.D.; Parimi, K.; Ward, J.V.

1984-01-03

Controlling gas to slurry volume ratio to achieve a gas holdup of about 0.4 when heating a flowing coal-oil slurry and a hydrogen containing gas stream allows operation with virtually any coal to solvent ratio and permits operation with efficient heat transfer and satisfactory pressure drops. The critical minimum gas flow rate for any given coal-oil slurry will depend on numerous factors such as coal concentration, coal particle size distribution, composition of the solvent (including recycle slurries), and type of coal. Further system efficiency can be achieved by operating with multiple heating zones to provide a high heat flux when the apparent viscosity of the gas saturated slurry is highest. Operation with gas flow rates below the critical minimum results in system instability indicated by temperature excursions in the fluid and at the tube wall, by a rapid increase and then decrease in overall pressure drop with decreasing gas flow rate, and by increased temperature differences between the temperature of the bulk fluid and the tube wall. At the temperatures and pressures used in coal liquefaction preheaters the coal-oil slurry and hydrogen containing gas stream behaves essentially as a Newtonian fluid at shear rates in excess of 150 sec[sup [minus]1]. The gas to slurry volume ratio should also be controlled to assure that the flow regime does not shift from homogeneous flow to non-homogeneous flow. Stable operations have been observed with a maximum gas holdup as high as 0.72. 29 figs.

Process for heating coal-oil slurries

DOEpatents

Braunlin, Walter A.; Gorski, Alan; Jaehnig, Leo J.; Moskal, Clifford J.; Naylor, Joseph D.; Parimi, Krishnia; Ward, John V.

1984-01-03

Controlling gas to slurry volume ratio to achieve a gas holdup of about 0.4 when heating a flowing coal-oil slurry and a hydrogen containing gas stream allows operation with virtually any coal to solvent ratio and permits operation with efficient heat transfer and satisfactory pressure drops. The critical minimum gas flow rate for any given coal-oil slurry will depend on numerous factors such as coal concentration, coal particle size distribution, composition of the solvent (including recycle slurries), and type of coal. Further system efficiency can be achieved by operating with multiple heating zones to provide a high heat flux when the apparent viscosity of the gas saturated slurry is highest. Operation with gas flow rates below the critical minimum results in system instability indicated by temperature excursions in the fluid and at the tube wall, by a rapid increase and then decrease in overall pressure drop with decreasing gas flow rate, and by increased temperature differences between the temperature of the bulk fluid and the tube wall. At the temperatures and pressures used in coal liquefaction preheaters the coal-oil slurry and hydrogen containing gas stream behaves essentially as a Newtonian fluid at shear rates in excess of 150 sec.sup. -1. The gas to slurry volume ratio should also be controlled to assure that the flow regime does not shift from homogeneous flow to non-homogeneous flow. Stable operations have been observed with a maximum gas holdup as high as 0.72.

Advanced direct coal liquefaction concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

During the first quarter of FY 1993, the Project proceeded close to the Project Plan. The analysis of the feed material has been completed as far as possible. Some unplanned distillation was needed to correct the boiling range of the Black Thunder solvent used during the autoclave tests. Additional distillation will be required if the same solvent is to be used for the bench unit tests. A decision on this is still outstanding. The solvent to be used with Illinois No. 6 coal has not yet been defined. As a result, the procurement of the feed and the feed analysismore » is somewhat behind schedule. Agglomeration tests with Black Thunder coal indicates that small agglomerates can be formed. However, the ash removal is quite low (about 10%), which is not surprising in view of the low ash content of the coal. The first series of autoclave tests with Black Thunder coal was completed as planned. Also, additional runs are in progress as repeats of previous runs or at different operating conditions based on the data obtained so far. The results are promising indicating that almost complete solubilization (close to 90%) of Black Thunder coal can be achieved in a CO/H[sub 2]O environment at our anticipated process conditions. The design of the bench unit has been completed. In contrast to the originally planned modifications, the bench unit is now designed based on a computerized control and data acquisition system. All major items of equipment have been received, and prefabrication of assemblies and control panels is proceeding on schedule. Despite a slight delay in the erection of the structural steel, it is anticipated that the bench unit will be operational at the beginning of April 1993.« less

Advanced direct coal liquefaction concepts. Quarterly report, October 1, 1992--December 31, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

During the first quarter of FY 1993, the Project proceeded close to the Project Plan. The analysis of the feed material has been completed as far as possible. Some unplanned distillation was needed to correct the boiling range of the Black Thunder solvent used during the autoclave tests. Additional distillation will be required if the same solvent is to be used for the bench unit tests. A decision on this is still outstanding. The solvent to be used with Illinois No. 6 coal has not yet been defined. As a result, the procurement of the feed and the feed analysismore » is somewhat behind schedule. Agglomeration tests with Black Thunder coal indicates that small agglomerates can be formed. However, the ash removal is quite low (about 10%), which is not surprising in view of the low ash content of the coal. The first series of autoclave tests with Black Thunder coal was completed as planned. Also, additional runs are in progress as repeats of previous runs or at different operating conditions based on the data obtained so far. The results are promising indicating that almost complete solubilization (close to 90%) of Black Thunder coal can be achieved in a CO/H{sub 2}O environment at our anticipated process conditions. The design of the bench unit has been completed. In contrast to the originally planned modifications, the bench unit is now designed based on a computerized control and data acquisition system. All major items of equipment have been received, and prefabrication of assemblies and control panels is proceeding on schedule. Despite a slight delay in the erection of the structural steel, it is anticipated that the bench unit will be operational at the beginning of April 1993.« less

Process for liquefying carbonaceous materials of high molecular weight and for separating liquefaction products

DOEpatents

Malek, John M.

1977-01-01

Process characterized by comprising successively a dissolution zone fed with carbonaceous solids and with a solvent, a high pressure hydrogenation zone provided with a source of hydrogen, and a hydrogenation products separation zone, wherein the improvement consists mainly in chemical upgrading of the liquidform products derived from the separation zone, and recycling a part of the upgraded products to the dissolution zone, this recycled part being of either positively acidic or positively basic properties for enhancing the dissolution - decomposition of base-acid structures present in the carbonaceous solid feed.

Solid dispersion of efavirenz in PVP K-30 by conventional solvent and kneading methods.

PubMed

Alves, Lariza Darlene Santos; de La Roca Soares, Mônica Felts; de Albuquerque, Camila Tavares; da Silva, Elica Rodrigues; Vieira, Alexandre Couto Carneiro; Fontes, Danilo Augusto Ferreira; Figueirêdo, Camila Bezerra Melo; Soares Sobrinho, José Lamartine; Rolim Neto, Pedro José

2014-04-15

Efavirenz (EFV) used as a part of the treatment of first choice in antiretroviral therapy for AIDS has low aqueous solubility and presents problems of absorption. We thus initially present a phase solubility diagram with carriers of different classes. With a view to obtaining a solid dispersion (SD) with suitable consistency to that of a solid formulation, we chose to use PVP K-30, since polymers present some of the best results. The kneading (KN) and solvent evaporation (EV) methods were thus used at different rates. These were characterized by the way of DSC, FT-IR, SEM, DR-X and dissolution. SD EV proved unsatisfactory, resulting in a decreased dissolution rate, despite the amorphous state of the samples, while the SD KN 4:1 (EFV:polymer) and physical mixtures (PM) had a higher rate of dissolution. SD KN and PM 4:1 were also evaluated for stability after storage, with benefits being observed in relation to EFV. Copyright © 2014. Published by Elsevier Ltd.

Coal liquefaction process wherein jet fuel, diesel fuel and/or ASTM No. 2 fuel oil is recovered

DOEpatents

Bauman, Richard F.; Ryan, Daniel F.

1982-01-01

An improved process for the liquefaction of coal and similar solid carbonaceous materials wherein a hydrogen donor solvent or diluent derived from the solid carbonaceous material is used to form a slurry of the solid carbonaceous material and wherein the naphthenic components from the solvent or diluent fraction are separated and used as jet fuel components. The extraction increases the relative concentration of hydroaromatic (hydrogen donor) components and as a result reduces the gas yield during liquefaction and decreases hydrogen consumption during said liquefaction. The hydrogenation severity can be controlled to increase the yield of naphthenic components and hence the yield of jet fuel and in a preferred embodiment jet fuel yield is maximized while at the same time maintaining solvent balance.

Improving the dissolution properties of curcumin using dense gas antisolvent technology.

PubMed

Kurniawansyah, Firman; Quachie, Lisa; Mammucari, Raffaella; Foster, Neil R

2017-04-15

The dissolution properties of curcumin are notoriously poor and hinder its bioavailability. To improve its dissolution properties, curcumin has been formulated with methyl-β-cyclodextrin and polyvinylpyrrolidone by the atomized rapid injection solvent extraction (ARISE) system. The compounds were co-precipitated from organic solutions using carbon dioxide at 30°C and 95bar as the antisolvent. Curcumin formulations were also produced by physical mixing and freeze drying for comparative purposes. The morphology, crystallinity, solid state molecular interactions, apparent solubility and dissolution profiles of samples were observed. The results indicate that the ARISE process is effective in the preparation of curcumin micro-composites with enhanced dissolution profiles compared to unprocessed material and products from physical mixing and freeze drying. Copyright © 2017 Elsevier B.V. All rights reserved.

Interlaboratory comparison of mutagenesis testing of coal fly ash derived from differenct coal conversion technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chrisp, C.; Hobbs, C.; Clark, R.

1979-01-01

This experiment showed that mutagenicity of fly ash derived from different coal conversion technologies, as determined by the Ames plate incorporation test, was similar in all three laboratories. The differences in mutagenic activity of each fly ash between laboratories with different solvent extraction methods were no greater than one order of magnitude. In addition, there were much smaller, but still significant differences in mutagenic activity between laboratories when the same solvent extract of a particular fly ash was tested in each laboratory. There were also significant differences in mutagenicity of the positive control mutagen (maximum of fivefold) between laboratories. Becausemore » of this difference in Ames test sensitivity between laboratories, the influence of the solvent extraction methods on differences in mutagenicity was not clear. However, the data suggested that either there were significant differences in the degree of sensitivity of Ames tests for different complex mixtures within each laboratory, or else there were differences in mutagen extraction efficiency between different solvent extraction methods. Both Ames test sensitivity and solvent extraction may be important. Further work would be necessary to separate the contribution of these two factors. An important aspect of further work would be to separate the contribution of the innate sensitivity of substrains of Ames tester strains in each laboratory from the possible effects of differences in Ames testing methodology. This could be done by testing the same extracts of fly ash and positive control mutagens with substrains of tester strains exchanged between laboratories. This work also implies that caution should be exercised in assuming that the same solvent would have the same efficiency for extraction of mutagens from different fly ashes even within the same laboratory.« less

Automated microfluidic platform for studies of carbon dioxide dissolution and solubility in physical solvents.

PubMed

Abolhasani, Milad; Singh, Mayank; Kumacheva, Eugenia; Günther, Axel

2012-05-07

We present an automated microfluidic (MF) approach for the systematic and rapid investigation of carbon dioxide (CO(2)) mass transfer and solubility in physical solvents. Uniformly sized bubbles of CO(2) with lengths exceeding the width of the microchannel (plugs) were isothermally generated in a co-flowing physical solvent within a gas-impermeable, silicon-based MF platform that is compatible with a wide range of solvents, temperatures and pressures. We dynamically determined the volume reduction of the plugs from images that were accommodated within a single field of view, six different downstream locations of the microchannel at any given flow condition. Evaluating plug sizes in real time allowed our automated strategy to suitably select inlet pressures and solvent flow rates such that otherwise dynamically self-selecting parameters (e.g., the plug size, the solvent segment size, and the plug velocity) could be either kept constant or systematically altered. Specifically, if a constant slug length was imposed, the volumetric dissolution rate of CO(2) could be deduced from the measured rate of plug shrinkage. The solubility of CO(2) in the physical solvent was obtained from a comparison between the terminal and the initial plug sizes. Solubility data were acquired every 5 min and were within 2-5% accuracy as compared to literature data. A parameter space consisting of the plug length, solvent slug length and plug velocity at the microchannel inlet was established for different CO(2)-solvent pairs with high and low gas solubilities. In a case study, we selected the gas-liquid pair CO(2)-dimethyl carbonate (DMC) and volumetric mass transfer coefficients 4-30 s(-1) (translating into mass transfer times between 0.25 s and 0.03 s), and Henry's constants, within the range of 6-12 MPa.

Liquefaction of sub-bituminous coal

DOEpatents

Schindler, Harvey D.; Chen, James M.

1986-01-01

Sub-bituminous coal is directly liquefied in two stages by use of a liquefaction solvent containing insoluble material as well as 850.degree. F.+ material and 850.degree. F.- material derived from the second stage, and controlled temperature and conversion in the second stage. The process is in hydrogen balance.

[Preparation and in vitro dissolution of magnolol solid dispersion].

PubMed

Tang, Lan; Qiu, Shuai-Bo; Wu, Lan; Lv, Long-Fei; Lv, Hui-Xia; Shan, Wei-Guang

2016-02-01

In this study, solid dispersion system of magnolol in croscarmellose sodium was prepared by using the solvent evaporation method, in order to increase the drug dissolution. And its dissolution behavior, stability and physical characteristics were studied. The solid dispersion was prepared with magnolol and croscarmellose sodium, with the proportion of 1∶5, the in vitro dissolution of magnolol solid dispersion was up to 80.66% at 120 min, which was 6.9 times of magnolol. The results of DSC (differential scanning calorimetry), IR (infra-red) spectrum and SEM (scanning electron microscopy) showed that magnolol existed in solid dispersion in an amorphous form. After an accelerated stability test for six months, the drug dissolution and content in magnolol solid dispersion showed no significant change. So the solid dispersion prepared with croscarmellose sodium as the carrier can remarkably improve the stability and dissolution of magnolol. Copyright© by the Chinese Pharmaceutical Association.

A New Method to Determine the Half-Life for Penicillin Using Microcalorimeter

NASA Astrophysics Data System (ADS)

Li, Z. X.; Zhao, W. W.

2015-01-01

The dissolution process of penicillin in normal saline and isotonic glucose solution was reported using a microcalorimeter. Both the integral and differential heats of solution were measured. The quantitative relationships between the amount of heat released and the quantity of dissolved penicillin were established. Meanwhile, the kinetics and the half-life of the dissolution processes as well as the enthalpy of solution, the entropy of dissolution, and the free energy of dissolution were determined. The results showed that a change of the solvent from normal saline to isotonic glucose solution had little effect on the half-life of penicillin in the dissolution process, and there was no significant difference between the stabilities of penicillin in isotonic glucose solution and normal saline. Moreover, the dissolution process of penicillin in isotonic glucose solution followed the first-order kinetics. These results could provide a theoretical basis for the clinical applications of penicillin.

Applications of supercritical fluids to enhance the dissolution behaviors of Furosemide by generation of microparticles and solid dispersions.

PubMed

De Zordi, Nicola; Moneghini, Mariarosa; Kikic, Ireneo; Grassi, Mario; Del Rio Castillo, Antonio Esau; Solinas, Dario; Bolger, Michael B

2012-05-01

The 'classical' loop diuretic drug Furosemide has been used as a model compound to investigate the possibility of enhancing the dissolution rate of poorly water-soluble drugs using supercritical anti-solvent techniques (SASs). In the present study we report upon the in vitro bioavailability improvement of Furosemide through particle size reduction as well as formation of solid dispersions (SDs) using the hydrophilic polymer Crospovidone. Supercritical carbon dioxide was used as the processing medium for these experiments. In order to successfully design a CO(2) antisolvent process, preliminary studies of Furosemide microparticles generation were conducted using Peng Robinson's Equation of State. These preliminary studies indicated using acetone as a solvent with pressures of 100 and 200bar and a temperature of 313K would yield optimum results. These operative conditions were then adopted for the SDs. Micronization by means of SAS at 200bar resulted in a significant reduction of crystallites, particle size, as well as improved dissolution rate in comparison with untreated drug. Furosemide recrystallized by SAS at 100bar and using traditional solvent evaporation. Moreover, changes in polymorphic form were observed in the 200bar samples. The physicochemical characterization of Furosemide:crospovidone SDs (1:1 and 1:2 w/w, respectively) generated by SAS revealed the presence of the drug amorphously dispersed in the 1:2 w/w sample at 100bar still remaining stable after 6months. This sample exhibits the best in vitro dissolution performance in the simulated gastric fluid (pH 1.2), in comparison with the same SD obtained by traditional method. No interactions between drug and polymer were observed. These results, together with the presence of the selected carrier, confirm that the use of Supercritical fluids antisolvent technology is a valid mean to increase the dissolution rate of poorly soluble drugs. Theoretical in vivo-in vitro relation was predicted by means of a pharmacokinetics mathematical model. Copyright © 2012 Elsevier B.V. All rights reserved.

Kinetics of the Removal of Iron Pyrite from Coal by Microbial Catalysis

PubMed Central

Hoffmann, Michael R.; Faust, Bruce C.; Panda, Fern A.; Koo, Hong H.; Tsuchiya, Henry M.

1981-01-01

Different strains of Thiobacillus ferrooxidans and Thiobacillus thiooxidans were used to catalyze the oxidative dissolution of iron pyrite, FeS2, in nine different coal samples. Kinetic variables and parametric factors that were determined to have a pronounced effect on the rate and extent of oxidative dissolution at a fixed Po2 were: the bacterial strain, the nitrogen/phosphorus molar ratio, the partial pressure of CO2, the coal source, and the total reactive surface area of FeS2. The overall rate of leaching, which exhibited a first-order dependence on the total surface area of FeS2, was analyzed mathematically in terms of the sum of a biochemical rate, ν1, and a chemical rate, ν2. Results of this study show that bacterial desulfurization (90 to 98%) of coal samples which are relatively high in pyritic sulfur can be achieved within a time-frame of 8 to 12 days when pulp densities are ≤20% and particle sizes are ≤74 μm. The most effective strains of T. ferrooxidans were those that were isolated from natural systems, and T. ferrooxidans ATCC 19859 was the most effective pure strain. The most effective nutrient media contained relatively low phosphate concentrations, with an optimal N/P molar ratio of 90:1. These results suggest that minimal nutrient additions may be required for a commercial desulfurization process. PMID:16345826

Solvent treatment of coal for improved liquefaction

DOEpatents

Appell, Herbert R.; Narain, Nand K.; Utz, Bruce R.

1986-05-06

Increased liquefaction yield is obtained by pretreating a slurry of solid carbonaceous material and a liquid hydrocarbonaceous solvent at a temperature above 200.degree. C. but below 350.degree. C. for a period of 10 minutes to four hours prior to exposure to liquefaction temperatures.

Ceramic Matrix Composites by Liquid Infiltration

DTIC Science & Technology

1988-01-01

28 List of Tables Page Table I Solubility of ZrCl4 in Various Solvents-----------8 Table II Experimental Matrix of Precursor Formation -------- 10...unreactive, solvent. 1 The solubility of ZrCl4 in acetonitrile is approximately 25% by weight. Dissolution is accompanied by evolution of heat and the solution...is very fluid. Evaporation of the solvent yields an off-white solid residue which appears to be a one to two complex or adduct of ZrCl4 with CH3CN

The influence of extractable organic matter on vitrinite reflectance suppression: A survey of kerogen and coal types

USGS Publications Warehouse

Barker, C.E.; Lewan, M.D.; Pawlewicz, M.J.

2007-01-01

The vitrinite reflectance suppression literature shows that while bitumen impregnation of the vitrinite group is often invoked as a significant contributor to suppression, its existence is not often supported by petrological evidence. This study examines bitumen impregnation as a factor in vitrinite suppression by comparing the vitrinite reflectance of source rock and coal samples before and after solvent-extraction. Bitumen, often defined as organic matter soluble or extractable in certain organic solvents, should be removed by Soxhlet method solvent extraction using chloroform. Removing the extractable bitumen should restore the suppressed reflectance to its true higher value. However, the solvent extracted samples averaged 0.014% Rv less than that of the unextracted samples. We conclude from these results and from other published data that reflectance suppression by bitumen impregnation in the vitrinite maceral group, above the huminite stage of gelification, is seemingly a rare phenomenon and whose effect on suppressing vitrinite reflectance is typically negligible. ?? 2006.

Self-Healing Materials for Ecotribology

PubMed Central

Shi, Shih-Chen; Huang, Teng-Feng

2017-01-01

Hydroxypropyl methylcellulose (HPMC) is a biopolymer that is biodegradable, environmentally friendly, and bio-friendly. Owing to its unique chemical structure, HPMC can reduce the coefficient of friction (COF) and frictional wear and thus possesses excellent lubrication properties. HPMC has good dissolvability in specific solvents. The present research focuses on the reversible dissolution reaction subsequent to the film formation of HPMC, with a view to the healing and lubrication properties of thin films. Raman spectroscopy was used to test the film-forming properties of HPMC and the dissolution characteristics of various solvents. In this study, the solvents were water, methanol, ethanol, and acetone. The results showed that the HPMC film had the highest dissolvability in water. The ball-on-disk wear test was used to analyze the lubrication properties of HPMC, and the results showed that HPMC had the same COF and lubrication properties as the original film after being subjected to the water healing treatment. The HPMC film can be reused, recycled, and refilled, making it an ideal lubricant for next-generation ecotribology. PMID:28772449

Dissolution thermodynamics and solubility of silymarin in PEG 400-water mixtures at different temperatures.

PubMed

Shakeel, Faiyaz; Anwer, Md Khalid

2015-01-01

An isothermal method was used to measure the solubility of silymarin in binary polyethylene glycol 400 (PEG 400) + water co-solvent mixtures at temperatures T = 298.15-333.15 K and pressure p = 0.1 MPa. Apelblat and Yalkowsky models were used to correlate experimental solubility data. The mole fraction solubility of silymarin was found to increase with increasing the temperature and mass fraction of PEG 400 in co-solvent mixtures. The root mean square deviations were observed in the range of 0.48-5.32% and 1.50-9.65% for the Apelblat equation and Yalkowsky model, respectively. The highest and lowest mole fraction solubility of silymarin was observed in pure PEG 400 (0.243 at 298.15 K) and water (1.46 × 10(-5) at 298.15 K). Finally, thermodynamic parameters were determined by Van't Hoff and Krug analysis, which indicated an endothermic and spontaneous dissolution of silymarin in all co-solvent mixtures.

Acetone-based cellulose solvent.

PubMed

Kostag, Marc; Liebert, Tim; Heinze, Thomas

2014-08-01

Acetone containing tetraalkylammonium chloride is found to be an efficient solvent for cellulose. The addition of an amount of 10 mol% (based on acetone) of well-soluble salt triethyloctylammonium chloride (Et3 OctN Cl) adjusts the solvent's properties (increases the polarity) to promote cellulose dissolution. Cellulose solutions in acetone/Et3 OctN Cl have the lowest viscosity reported for comparable aprotic solutions making it a promising system for shaping processes and homogeneous chemical modification of the biopolymer. Recovery of the polymer and recycling of the solvent components can be easily achieved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dielectric relaxation of ethylene carbonate and propylene carbonate from molecular dynamics simulations

DOE PAGES

Chaudhari, Mangesh I.; You, Xinli; Pratt, Lawrence R.; ...

2015-11-24

Ethylene carbonate (EC) and propylene carbonate (PC) are widely used solvents in lithium (Li)-ion batteries and supercapacitors. Ion dissolution and diffusion in those media are correlated with solvent dielectric responses. Here, we use all-atom molecular dynamics simulations of the pure solvents to calculate dielectric constants and relaxation times, and molecular mobilities. The computed results are compared with limited available experiments to assist more exhaustive studies of these important characteristics. As a result, the observed agreement is encouraging and provides guidance for further validation of force-field simulation models for EC and PC solvents.

Deashing of coal liquids with ceramic membrane microfiltration and diafiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishop, B.; Goldsmith, R.

1995-12-31

Removal of mineral matter from liquid hydrocarbons derived from the direct liquefaction of coal is required for product acceptability. Current methods include critical solvent deashing (Rose{sup {reg_sign}} process from Kerr-McGee) and filtration (U.S. Filter leaf filter as used by British Coal). These methods produce ash reject streams containing up to 15% of the liquid hydrocarbon product. Consequently, CeraMem proposed the use of low cost, ceramic crossflow membranes for the filtration of coal liquids bottoms to remove mineral matter and subsequent diafiltration (analogous to cake washing in dead-ended filtration) for the removal of coal liquid from the solids stream. The usemore » of these ceramic crossflow membranes overcomes the limitations of traditional polymeric crossflow membranes by having the ability to operate at elevated temperature and to withstand prolonged exposure to hydrocarbon and solvent media. In addition, CeraMem`s membrane filters are significantly less expensive than competitive ceramic membranes due to their unique construction. With these ceramic membrane filters, it may be possible to reduce the product losses associated with traditional deashing processes at an economically attractive cost. The performance of these ceramic membrane microfilters is discussed.« less

Methods for detecting the mobility of trace elements during medium-temperature pyrolysis

USGS Publications Warehouse

Shiley, R.H.; Konopka, K.L.; Cahill, R.A.; Hinckley, C.C.; Smith, Gerard V.; Twardowska, H.; Saporoschenko, Mykola

1983-01-01

The mobility (volatility) of trace elements in coal during pyrolysis has been studied for distances of up to 40 cm between the coal and the trace element collector, which was graphite or a baffled solvent trap. Nineteen elements not previously recorded as mobile were detected. ?? 1983.

Superacid Catalyzed Depolymerization and Conversion of Coals. Final Technical Report. [HF:BF{sub 2}/H{sub 2}

DOE R&D Accomplishments Database

Olah, G.

1980-01-01

We were interested in applying superacid catalyzed cleavage-depolymerization and ionic hydrogenation low temperature conversion of coal to liquid hydrocarbon, as well as obtaining information about the reactions involved and the structure of intermediates of the coal liquefaction process. In order to show the feasibility of our proposed research we have carried out preliminary investigation in these areas. Preceding our work there was no practical application of a superacid system to coal liquefaction. We carried out an extensive study of the potential of the HF:BF{sub 3}/H{sub 2} system for coal hydroliquefaction. Under varying conditions of reactant ratio, reaction time and temperature, we were able to obtain over 95% pyridine extractible product by treating coal in HF:BF{sub 3}:H{sub 2} system at approx. 100 degrees C for 4 hours. The coal to acid ratio was 1:5 and FB{sub 3} at 900 psi and H{sub 2} at 500 psi were used. These are extremely encouraging results in that the conditions used are drastically milder than those used in any known process, such as Exxon donor solvent and related processes. The cyclohexane extractibility of the treated coal was as high as 27% and the yield of liquid distillate at 400 degrees C/5 x 10{sup -3}/sup torr/ was approx. 30%. The infrared spectrum of product coal, extracts and distillates were distinctly different from the starting coal and show a significant increase in the amount of saturates. The {sup 1}H NMR spectrum of cyclohexane extract of the treated coal shows essentially all aliphatic photons. The spectra of other treated coal extracts show increased amounts and types of aliphatic protons as well as significant amounts of protons bound to unsaturated sites. This again indicates that the HF-BF{sub 3} system is depolymerizing the coal to small fragments which are soluble in non-polar solvents.

Coal liquefaction process

DOEpatents

Wright, Charles H.

1986-01-01

A process for the liquefaction of coal wherein raw feed coal is dissolved in recycle solvent with a slurry containing recycle coal minerals in the presence of added hydrogen at elevated temperature and pressure. The highest boiling distillable dissolved liquid fraction is obtained from a vacuum distillation zone and is entirely recycled to extinction. Lower boiling distillable dissolved liquid is removed in vapor phase from the dissolver zone and passed without purification and essentially without reduction in pressure to a catalytic hydrogenation zone where it is converted to an essentially colorless liquid product boiling in the transportation fuel range.

Isolation and identification of fatty acid amides from Shengli coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ming-Jie Ding; Zhi-Min Zong; Ying Zong

Shengli coal, a Chinese brown coal, was extracted with carbon disulfide and the extract was gradiently eluted with n-hexane and ethyl acetate (EA)/n-hexane mixed solvents with different concentrations of EA in a silica gel-filled column. A series of fatty acid amides, including fourteen alkanamides (C{sub 15}-C{sub 28}) and three alkenamides (C{sub 18} and C{sub 22}), were isolated from the coal by this method and analyzed with a gas chromatography/mass spectrometry. 26 refs., 2 figs., 2 tabs.

Probing coal architecture by magnetic resonance microscopy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Botto, R. E.; Clifford, D. J.; Gregory, D. M.

1999-02-24

Time-resolved MRM investigations of a well-characterized suite of cross-linked polymers have yielded information on the nature of the solvent transport dynamics and mechanical relaxation of the networks. Network response parameters were then used to assess the macroscopic properties and cross-link densities of polymers with the degree of curing. This new approach is presently being developed to elucidate the complex macromolecular nature of coals and the variation with coal rank.

Partial dissolution of ACQ-treated wood in lithium chloride/N-methyl-2-pyrrolidinone: Separation of copper from potential lignocellulosic feedstocks

Treesearch

Thomas L. Eberhardt; Stan Lebow; Karen G. Reed

2012-01-01

A cellulose solvent system based on lithium chloride (LiCl) in N-methyl-2-pyrrolidinone (NMP) was used to assess the merits of partial dissolutions of coarsely ground wood samples. Alkaline Copper Quaternary (ACQ)-treated pine wood was of particular interest for treatment given the potential to generate a copper- rich stream apart from solid and/or liquid...

Solubilization of the poorly water soluble drug, telmisartan, using supercritical anti-solvent (SAS) process.

PubMed

Park, Junsung; Cho, Wonkyung; Cha, Kwang-Ho; Ahn, Junhyun; Han, Kang; Hwang, Sung-Joo

2013-01-30

Telmisartan is a biopharmaceutical classification system (BCS) class II drug that has extremely low water solubility but is freely soluble in highly alkalized solutions. Few organic solvents can dissolve telmisartan. This solubility problem is the main obstacle achieving the desired bioavailability. Because of its unique characteristics, the supercritical anti-solvent (SAS) process was used to BCS class II drug in a variety of ways including micronization, amorphization and solid dispersion. Solid dispersions were prepared using hydroxypropylmethylcellulose/polyvinylpyrrolidone (HPMC/PVP) at 1:0.5, 1:1, and 1:2 weight ratios of drug to polymer, and pure telmisartan was also treated using the SAS process. Processed samples were characterized for morphology, particle size, crystallinity, solubility, dissolution rate and polymorphic stability. After the SAS process, all samples were converted to the amorphous form and were confirmed to be hundreds nm in size. Solubility and dissolution rate were increased compared to the raw material. Solubility tended to increase with increases in the amount of polymer used. However, unlike the solubility results, the dissolution rate decreased with increases in polymer concentration due to gel layer formation of the polymer. Processed pure telmisartan showed the best drug release even though it had lower solubility compared to other solid dispersions; however, because there were no stabilizers in processed pure telmisartan, it recrystallized after 1 month under severe conditions, while the other solid dispersion samples remained amorphous form. We conclude that after controlling the formulation of solid dispersion, the SAS process could be a promising approach for improving the solubility and dissolution rate of telmisartan. Copyright © 2012 Elsevier B.V. All rights reserved.

Replica-exchange molecular dynamics simulations of cellulose solvated in water and in the ionic liquid 1-butyl-3-methylimidazolium chloride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mostofian, Barmak; Cheng, Xiaolin; Smith, Jeremy C.

2014-09-02

Ionic liquids have become a popular solvent for cellulose pretreatment in biorefineries due to their efficiency in dissolution and their reusability. Understanding the interactions between cations, anions, and cellulose is key to the development of better solvents and the improvement of pretreatment conditions. While previous studies described the interactions between ionic liquids and cellulose fibers, shedding light on the initial stages of the cellulose dissolution process, we study the end state of that process by exploring the structure and dynamics of a single cellulose decamer solvated in 1-butyl-3-methyl-imidazolium chloride (BmimCl) and in water using replica-exchange molecular dynamics. In both solvents,more » global structural features of the cellulose chain are similar. However, analyses of local structural properties show that cellulose explores greater conformational variability in the ionic liquid than in water. For instance, in BmimCl the cellulose intramolecular hydrogen bond O3H'••• O5 is disrupted more often resulting in greater flexibility of the solute. Our results indicate that the cellulose chain is more dynamic in BmimCl than in water, which may play a role in the favorable dissolution of cellulose in the ionic liquid. Here, the calculation of the configurational entropy of the cellulose decamer confirms its higher conformational flexibility in BmimCl than in water at elevated temperatures.« less

In Situ Monitoring and Modeling of the Solution-Mediated Polymorphic Transformation of Rifampicin: From Form II to Form I.

PubMed

Guo, Nannan; Hou, Baohong; Wang, Na; Xiao, Yan; Huang, Jingjing; Guo, Yanmei; Zong, Shuyi; Hao, Hongxun

2018-01-01

In this article, the solution-mediated polymorphic transformation of rifampicin was investigated and simulated in 3 solvents at 30°C. The solid-state form I and form II of rifampicin was characterized by powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). To explore the relative stability, solubility data of form I and form II of rifampicin in butan-1-ol were determined using a dynamical method. In addition, Raman spectroscopy and focused beam reflectance measurement were used to in situ monitor the transformation of rifampicin from form II to form I. The liquid state concentration of rifampicin was measured by UV spectroscopic method. To investigate the effect of solvent on transformation, the transformation experiments were carried out in 3 solvents. Furthermore, a mathematical model was built to describe the kinetics of dissolution, nucleation, and growth processes during transformation by using experimental data. By combination of experimental and simulation results, it was found that the transformation process of rifampicin is controlled by dissolution of form II in heptane, whereas the transformation in hexane and octane was firstly controlled by dissolution of solid-state form and then controlled by growth of form I. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Electrolyte with Low Polysulfide Solubility for Li-S Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Ke; Wu, Qin; Tong, Xiao

Here, Li-S battery is one of the most promising next generation rechargeable battery technologies due to its high theoretical energy density and low material cost. While its success is impeded by the low energy efficiency and fast capacity fade primarily caused by the discharge intermediates, Li-polysulfides (PS), dissolution in the electrolyte. Mitigation of PS dissolution in electrolyte involves the search of new electrolyte solvent system that exhibits poor solvation to the PS while still have good solvation ability to the electrolyte salt for high ionic conductivity. Applying co-solvents with reduced solvating power but compatible with the state of art Li-Smore » battery’s ether-based electrolyte is one of the most promising concepts. This route is also advantageous of having a low scale-up cost. With the aids of Quantum Chemical Calculation, we have identified high carbon-to-oxygen (C/O) ratio ethers as co-solvent in the new electrolytes that effectively impede PS dissolution while still maintaining high ionic conductivity. Significantly improved cycle life and cycling Coulombic efficiency are observed for Li-S cells using the new composite electrolytes. Anode analysis with different methods also demonstrate that reducing electrolyte’s PS solubility results in less sulfur total amount on the lithium anode surface and lower ratio of the longer-chain PS, which is probably a sign of suppressed side reactions between the anode and PS in the electrolyte.« less

Electrolyte with Low Polysulfide Solubility for Li-S Batteries

DOE PAGES

Sun, Ke; Wu, Qin; Tong, Xiao; ...

2018-05-23

Here, Li-S battery is one of the most promising next generation rechargeable battery technologies due to its high theoretical energy density and low material cost. While its success is impeded by the low energy efficiency and fast capacity fade primarily caused by the discharge intermediates, Li-polysulfides (PS), dissolution in the electrolyte. Mitigation of PS dissolution in electrolyte involves the search of new electrolyte solvent system that exhibits poor solvation to the PS while still have good solvation ability to the electrolyte salt for high ionic conductivity. Applying co-solvents with reduced solvating power but compatible with the state of art Li-Smore » battery’s ether-based electrolyte is one of the most promising concepts. This route is also advantageous of having a low scale-up cost. With the aids of Quantum Chemical Calculation, we have identified high carbon-to-oxygen (C/O) ratio ethers as co-solvent in the new electrolytes that effectively impede PS dissolution while still maintaining high ionic conductivity. Significantly improved cycle life and cycling Coulombic efficiency are observed for Li-S cells using the new composite electrolytes. Anode analysis with different methods also demonstrate that reducing electrolyte’s PS solubility results in less sulfur total amount on the lithium anode surface and lower ratio of the longer-chain PS, which is probably a sign of suppressed side reactions between the anode and PS in the electrolyte.« less

Dissolution DNP-NMR spectroscopy using galvinoxyl as a polarizing agent

NASA Astrophysics Data System (ADS)

Lumata, Lloyd L.; Merritt, Matthew E.; Malloy, Craig R.; Sherry, A. Dean; van Tol, Johan; Song, Likai; Kovacs, Zoltan

2013-02-01

The goal of this work was to test feasibility of using galvinoxyl (2,6-di-tert-butyl-α-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1-ylidene)-p-tolyloxy) as a polarizing agent for dissolution dynamic nuclear polarization (DNP) NMR spectroscopy. We have found that galvinoxyl is reasonably soluble in ethyl acetate, chloroform, or acetone and the solutions formed good glasses when mixed together or with other solvents such as dimethyl sulfoxide. W-band electron spin resonance (ESR) measurements revealed that galvinoxyl has an ESR linewidth D intermediate between that of carbon-centered free radical trityl OX063 and the nitroxide-based 4-oxo-TEMPO, thus the DNP with galvinoxyl for nuclei with low gyromagnetic ratio γ such as 13C and 15N is expected to proceed predominantly via the thermal mixing process. The optimum radical concentration that would afford the highest 13C nuclear polarization (approximately 6% for [1-13C]ethyl acetate) at 3.35 T and 1.4 K was found to be around 40 mM. After dissolution, large liquid-state NMR enhancements were achieved for a number of 13C and 15N compounds with long spin-lattice relaxation time T1. In addition, the hydrophobic galvinoxyl free radical can be easily filtered out from the dissolution liquid when water is used as the solvent. These results indicate that galvinoxyl can be considered as an easily available free radical polarizing agent for routine dissolution DNP-NMR spectroscopy.

Structural properties and adsorption capacity of holocellulose aerogels synthesized from an alkali hydroxide-urea solution

NASA Astrophysics Data System (ADS)

Kwon, Gu-Joong; Kim, Dae-Young; Hwang, Jae-Hyun; Kang, Joo-Hyon

2014-05-01

A tulip tree was used to synthesize a holocellulose aerogel from an aqueous alkali hydroxide-urea solution with the substitution of an organic solvent followed by freeze-drying. For comparison, the synthesized holocellulose aerogels were divided into two groups according to the source of the hydrogel, an upper suspended layer and a bottom concentrated layer of the centrifuged solution of cellulose and NaOH/urea solvents. We investigated the effects of the temperature of the pre-cooled NaOH/urea solution ( i.e., dissolution temperature) on the pore structure and the adsorption capacity of the holocellulose aerogel. A nano-fibrillar network structure of the holocellulose aerogel was observed, with little morphological difference in pore structure for different dissolution temperatures. Both micropores and mesopores were observed in the holocellulose aerogel. The specific surface area of the holocellulose aerogel was generally greater at lower dissolution temperatures. In a series of adsorption tests using methylene blue, the holocellulose aerogel showed the greatest adsorption capacity at the lowest dissolution temperature tested (-2°C). However, the dissolution temperature generally had little effect on the adsorption capacity. The holocellulose aerogel produced from the upper suspended layer of the centrifuged hydrogel solution showed a greater porosity and adsorption capacity than the one produced from the bottom concentrated layer. Overall, the aerogel made by utilizing a delignified tulip tree display a high surface area and a high adsorption property, indicating its possible application in eco-friendly adsorption materials.

Concept of a self-associated multimer structure of coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagarin, S.G.; Krichko, A.A.

1984-01-01

The paper examines the role of donor-acceptor reaction in the binding of the individual components forming the structure of the organic coal mass, and analyses the manifestations of this reaction during liquefaction. The authors put forward the concept of self-associated polymers in the coal structure, in accordance with which the organic coal mass has spatial and energetic distribution of the donor and acceptor sectors of structure. It is the specific reaction between these which produces the necessary stability to the polymer system under normal conditions. The authors propose a mechanism for the action of solvents and various additives in themore » liquefaction of coal.« less

The analysis of heavy metal in leaching liquid of coal

NASA Astrophysics Data System (ADS)

Cao, Hongmei; Li, Guanglou; Zhang, Lu

2018-02-01

In this paper, heavy metals in coal were extracted by pure water to simulate the leaching effect of natural precipitation or artificial rainfall on outdoor storage of coal. The results show that the leaching liquid pH was slightly declining, and Cu, Zn, Pb, Cd were in μg/L level, far less than the hazardous waste identification standard of GB5085.3-2007. It suggests that leaching liquid was less harmful to environment when coal was immersed by big amount of water. In the case of spray or precipitation less, the pH drop was more obvious, leaching of heavy metals more, and the general elution of the initial dissolution of the most obvious. Although the amount of small but more toxic, the relevant management should be alert to its harmful.

Study of the solid state of carbamazepine after processing with gas anti-solvent technique.

PubMed

Moneghini, M; Kikic, I; Voinovich, D; Perissutti, B; Alessi, P; Cortesi, A; Princivalle, F; Solinas, D

2003-09-01

The purpose of this study was to investigate the influence of supercritical CO2 processing on the physico-chemical properties of carbamazepine, a poorly soluble drug. The gas anti-solvent (GAS) technique was used to precipitate the drug from three different solvents (acetone, ethylacetate and dichloromethane) to study how they would affect the final product. The samples were analysed before and after treatment by scanning electron microscopy analysis and laser granulometry for possible changes in the habitus of the crystals. In addition, the solid state of the samples was studied by means of X-ray powder diffraction, differential scanning calorimetry, diffuse reflectance Fourier-transform infrared spectroscopy and hot stage microscopy. Finally, the in vitro dissolution tests were carried out. The solid state analysis of both samples untreated and treated with CO2, showed that the applied method caused a transition from the starting form III to the form I as well as determined a dramatic change of crystal morphology, resulting in needle-shaped crystals, regardless of the chosen solvent. In order to identify which process was responsible for the above results, carbamazepine was further precipitated from the same three solvents by traditional evaporation method (RV-samples). On the basis of this cross-testing, the solvents were found to be responsible for the reorganisation into a different polymorphic form, and the potential of the GAS process to produce micronic needle shaped particles, with an enhanced dissolution rate compared to the RV-carbamazepine, was ascertained.

Separation and characterization of polycyclic aromatic hydrocarbons and alkylphenols in coal derived solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hurtubise, R.J.; Allen, T.W.; Hussain, A.

1981-03-29

Dry-column chromatography with an aluminum oxide stationary phase and a n-hexane-ether (19:1) mobile phase was used to separate polycyclic aromatic hydrocarbons (PAH) by ring size. Prior to the dry-column chromatography step, the coal derived solvents were added to an acid treated silica gel column and eluted with chloroform. This step removed pyridine-type nitrogen heterocycles. After separation of the individual ring fractions, the fractions were further separated by either thin layer chromatography (TLC) or high performance liquid chromatography (HPLC). If TLC was used, then after separation fluorescence profiles of each PAH ring fraction distributed on 30%-acetylated cellulose chromatoplates were obtained withmore » a spectrodensitometer. Measurement of fluorescence peak heights gave an approximate measure of the amount of the 3-, 4-, 5-, and 6- ring PAH. For HPLC separation, the 3- and 4- ring PAH fractions obtained from the dry-column chromatography step were separated with a ..mu..-Bondapak C/sub 18/ column and methanol:water (65:35) mobile phase. The HPLC separated PAH were characterized by chromatographic correlation factors and corrected fluorescence excitation spectra. Alkylphenols were identified in coal recycle solvent sample following separation by HPLC.« less

Evaluation of selected elastomer O-ring pump seals for service at the Wilsonville, Alabama, Advanced Coal Liquefaction Research and Development Facility. [Ethylenepropylenediene monomer compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skena, C.C.; Keiser, J.R.

1986-08-01

Previous laboratory tests of elastomer O-rings in coal liquefaction solvents conducted at L'Garde, Inc., indicated that certain ethylenepropylenediene monomer (EPDM) compounds provided the best performance when a backup ring was used to limit swelling. Before service testing in a pump at the Wilsonville, Alabama, Advanced Coal Liquefaction Research and Development Facility, tests of six selected elastomers in the appropriate Wilsonville-produced solvent were conducted at Oak Ridge National Laboratory (ORNL). The ORNL tests measured the elastomers' changes in cross section, weight, density, and relative flexibility. Although two perfluoroelastomers showed less degradation of most properties during these tests, it was decided tomore » proceed with service testing of two EPDM elastomers because of their much lower cost. 5 refs., 14 figs., 7 tabs.« less

CONTINUOUS DISSOLVER EXTRACTOR FOR PROCESSING METAL

DOEpatents

Lemon, R.B.; Buckham, J.A.

1959-02-01

An apparatus is presented for the continuous dissolution of metal slugs in an aqueous acid and sequential continuous extraction of selected metal values from the acid solution by counter-current contact with an organic solvent. The apparatus comprises a cylindrical tank divided into upper and lower sections. Dissolution of the metal slug takes place in the lower section and the solution so produced is continuously fed to the topmost plate of the upper extraction section. An immiscible organic extractant is continuously passed by a pulsing pump into the lowermost unit of the extraction section. Suitable piping and valving permits of removing the aqueous raffinate solution from the lowermost portion of the extraction section, and simultaneous removal of organic solvent extractant containing the desired product from the uppermost portion of the extraction section.

Development and Validation of Discriminating and Biorelevant Dissolution Test for Lornoxicam Tablets

PubMed Central

Anumolu, P. D.; Sunitha, G.; Bindu, S. Hima; Satheshbabu, P. R.; Subrahmanyam, C. V. S.

2015-01-01

The establishment of biorelevant and discriminating dissolution procedure for drug products with limited water solubility is a useful technique for qualitative forecasting of the in vivo behavior of formulations. It also characterizes the drug product performance in pharmaceutical development. Lornoxicam, a BCS class-II drug is a nonsteroidal antiinflammatory drug of the oxicam class, has no official dissolution media available in the literature. The objective of present work was to develop and validate a discriminating and biorelevant dissolution test for lornoxicam tablet dosage forms. To quantify the lornoxicam in dissolution samples, UV spectrophotometric method was developed using 0.01M sodium hydroxide solution as solvent at λma×376 nm. After evaluation of saturation solubility, dissolution, sink conditions and stability of lornoxicam bulk drug in different pH solutions and biorelevant media, the dissolution method was optimized using USP paddle type apparatus at 50 rpm rotation speed and 500 ml simulated intestinal fluid as discriminating and biorelevant dissolution medium. The similarity factor (f2) were investigated for formulations with changes in composition and manufacturing variations, values revealed that dissolution method having discriminating power and method was validated as per standard guidelines. The proposed dissolution method can be effectively applied for routine quality control in vitro dissolution studies of lornoxicam in tablets and helpful to pharmacopoeias. PMID:26180277

Development and Validation of Discriminating and Biorelevant Dissolution Test for Lornoxicam Tablets.

PubMed

Anumolu, P D; Sunitha, G; Bindu, S Hima; Satheshbabu, P R; Subrahmanyam, C V S

2015-01-01

The establishment of biorelevant and discriminating dissolution procedure for drug products with limited water solubility is a useful technique for qualitative forecasting of the in vivo behavior of formulations. It also characterizes the drug product performance in pharmaceutical development. Lornoxicam, a BCS class-II drug is a nonsteroidal antiinflammatory drug of the oxicam class, has no official dissolution media available in the literature. The objective of present work was to develop and validate a discriminating and biorelevant dissolution test for lornoxicam tablet dosage forms. To quantify the lornoxicam in dissolution samples, UV spectrophotometric method was developed using 0.01M sodium hydroxide solution as solvent at λma×376 nm. After evaluation of saturation solubility, dissolution, sink conditions and stability of lornoxicam bulk drug in different pH solutions and biorelevant media, the dissolution method was optimized using USP paddle type apparatus at 50 rpm rotation speed and 500 ml simulated intestinal fluid as discriminating and biorelevant dissolution medium. The similarity factor (f2) were investigated for formulations with changes in composition and manufacturing variations, values revealed that dissolution method having discriminating power and method was validated as per standard guidelines. The proposed dissolution method can be effectively applied for routine quality control in vitro dissolution studies of lornoxicam in tablets and helpful to pharmacopoeias.

Solvent Vapor Annealing of Amorphous Carbamazepine Films for Fast Polymorph Screening and Dissolution Alteration.

PubMed

Schrode, Benedikt; Bodak, Brigitta; Riegler, Hans; Zimmer, Andreas; Christian, Paul; Werzer, Oliver

2017-09-30

Solubility enhancement and thus higher bioavailability are of great importance and a constant challenge in pharmaceutical research whereby polymorph screening and selection is one of the most important tasks. A very promising approach for polymorph screening is solvent vapor annealing where a sample is exposed to an atmosphere saturated with molecules of a specific chemical/solvent. In this work, amorphous carbamazepine thin films were prepared by spin coating, and the transformation into crystalline forms under exposure to solvent vapors was investigated. Employing grazing incidence X-ray diffraction, four distinct carbamazepine polymorphs, a solvate, and hydrates could be identified, while optical microscopy showed mainly spherulitic morphologies. In vitro dissolution experiments revealed different carbamazepine release from the various thin-film samples containing distinct polymorphic compositions: heat treatment of amorphous samples at 80 °C results in an immediate release; samples exposed to EtOH vapors show a drug release about 5 times slower than this immediate one; and all the others had intermediate release profiles. Noteworthy, even the sample of slowest release has a manifold faster release compared to a standard powder sample demonstrating the capabilities of thin-film preparation for faster drug release in general. Despite the small number of samples in this screening experiment, the results clearly show how solvent vapor annealing can assist in identifying potential polymorphs and allows for estimating their impact on properties like bioavailability.

Supercritical antisolvent precipitation of nimesulide: preliminary experiments.

PubMed

Moneghini, M; Perissutti, B; Vecchione, F; Kikic, I; Alessi, P; Cortesi, A; Princivalle, F

2007-07-01

The purpose of this preliminary study was to investigate the physico-chemical properties of nimesulide precipitated by continuous supercritical antisolvent (SAS) from different organic solvents like acetone, chloroform and dichloromethane at 40 degrees C and 80, 85 and 88 bar, respectively. Scanning electron microscopy, differential scanning calorimetry, X-Ray diffractometry and in vitro dissolution tests were employed to study how the technological process and the solvent nature would affect the final product. SAS-processed nimesulide particles showed dramatic morphological change in crystalline structure if compared to native nimesulide, resulting in needle and thin rods shaped crystals. The solid state analysis showed that using chloroform or dichloromethane as a solvent the drug solid state remained substantially unchanged, whilst if using acetone the applied method caused a transition from the starting form I to the meta-stable form II. So as to identify which process was responsible for this result, nimesulide was further precipitated from the same solvent by conventional evaporation method (RV-sample). On the basis of this comparison, the solvent was found to be responsible for the re-organization into the different polymorphic form and the potential of the SAS process to produce micronic needle shaped particles, with an enhanced dissolution rate if compared to the to the pure drug, was ascertained. Finally, the stability of the nimesulide form II, checked by DSC analysis, was ruled on over a period of 15 months.

Donor solvent coal liquefaction with bottoms recycle at elevated pressure

DOEpatents

Bauman, Richard F.; Taunton, John W.; Anderson, George H.; Trachte, Ken L.; Hsia, Steve J.

1982-01-01

An improved process for liquefying solid carbonaceous materials wherein increased naphtha yields are achieved by effecting the liquefaction at a pressure within the range from about 1750 to about 2800 psig in the presence of recycled bottoms and a hydrogen-donor solvent containing at least 0.8 wt % donatable hydrogen. The liquefaction is accomplished at a temperature within the range from about 700.degree. to about 950.degree. F. The coal:bottoms ratio in the feed to liquefaction will be within the range from about 1:1 to about 5:1 and the solvent or diluent to total solids ratio will be at least 1.5:1 and preferably within the range from about 1.6:1 to about 3:1. The yield of naphtha boiling range materials increases as the pressure increases but generally reaches a maximum at a pressure within the range from about 2000 to about 2500 psig.

Coal liquefaction process

DOEpatents

Wright, C.H.

1986-02-11

A process is described for the liquefaction of coal wherein raw feed coal is dissolved in recycle solvent with a slurry containing recycle coal minerals in the presence of added hydrogen at elevated temperature and pressure. The highest boiling distillable dissolved liquid fraction is obtained from a vacuum distillation zone and is entirely recycled to extinction. Lower boiling distillable dissolved liquid is removed in vapor phase from the dissolver zone and passed without purification and essentially without reduction in pressure to a catalytic hydrogenation zone where it is converted to an essentially colorless liquid product boiling in the transportation fuel range. 1 fig.

Applications of micellar enzymology to clean coal technology. [Laccase from Polyporus versicolor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, C.T.

1990-07-24

This project is designed to develop methods for pre-combustion coal remediation by implementing recent advances in enzyme biochemistry. The novel approach of this study is incorporation of hydrophilic oxidative enzymes in reverse micelles in an organic solvent. Enzymes from commercial sources or microbial extracts are being investigated for their capacity to remove organic sulfur from coal by oxidation of the sulfur groups, splitting of C-S bonds and loss of sulfur as sulfuric acid. Dibenzothiophen (DBT) and ethylphenylsulfide (EPS) are serving as models of organic sulfur-containing components of coal in initial studies.

Characterization of Rare Earth Elements in in Clay Deposits Associated with Central Appalachian Coal Seams

NASA Astrophysics Data System (ADS)

Scott, M.; Verba, C.; Falcon, A.; Poston, J.; McKoy, M.

2017-12-01

Because of their multiple uses in clean energy technologies, rare earth elements (REE) are critical for national economic and energy security. With no current domestic source, supply remains a major concern for domestic security. Underclay - specifically the layer of stratum beneath a coal bed - is a potentially rich source of REE. This study focuses on the characterization and ion exchange recovery of REE from underclay samples from the Lower Freeport, Middle Kittanning, and Pittsburgh coal seams in West Virginia. Multimodal techniques provided quantitative assessments of REE-bearing mineral phases in select underclays and the influence of organic acid rock treatment on the recovery of REE from both exchangeable and crystalline mineral phases present. All samples are from extensively weathered horizons that contain abundant kaolinite and illite. Total REE concentrations range from 250-450 ppm and all samples have a HREE/LEEE ratio >20%. Rare earth element bearing minerals identified in the clay are monazite, xenotime, florencite, and crandallite. Our selective recovery approach is designed to isolate and recover REE through partial dissolution of the clay matrix and ion exchange rather than dissolution/recovery of phosphate or aluminosilicate bound REE. These results provide a better understanding of coal seam underclay, the affinity of REEs for specific ligands and colloids, and how the rock and ligands respond to different chemical treatments. These processes are important to the development and commercialization of efficient and cost effective methods to extract REE from domestic geologic deposits and recover into salable forms.

Create a Consortium and Develop Premium Carbon Products from Coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frank Rusinko; John Andresen; Jennifer E. Hill

2006-01-01

The objective of these projects was to investigate alternative technologies for non-fuel uses of coal. Special emphasis was placed on developing premium carbon products from coal-derived feedstocks. A total of 14 projects, which are the 2003 Research Projects, are reported herein. These projects were categorized into three overall objectives. They are: (1) To explore new applications for the use of anthracite in order to improve its marketability; (2) To effectively minimize environmental damage caused by mercury emissions, CO{sub 2} emissions, and coal impounds; and (3) To continue to increase our understanding of coal properties and establish coal usage in non-fuelmore » industries. Research was completed in laboratories throughout the United States. Most research was performed on a bench-scale level with the intent of scaling up if preliminary tests proved successful. These projects resulted in many potential applications for coal-derived feedstocks. These include: (1) Use of anthracite as a sorbent to capture CO{sub 2} emissions; (2) Use of anthracite-based carbon as a catalyst; (3) Use of processed anthracite in carbon electrodes and carbon black; (4) Use of raw coal refuse for producing activated carbon; (5) Reusable PACs to recycle captured mercury; (6) Use of combustion and gasification chars to capture mercury from coal-fired power plants; (7) Development of a synthetic coal tar enamel; (8) Use of alternative binder pitches in aluminum anodes; (9) Use of Solvent Extracted Carbon Ore (SECO) to fuel a carbon fuel cell; (10) Production of a low cost coal-derived turbostratic carbon powder for structural applications; (11) Production of high-value carbon fibers and foams via the co-processing of a low-cost coal extract pitch with well-dispersed carbon nanotubes; (12) Use of carbon from fly ash as metallurgical carbon; (13) Production of bulk carbon fiber for concrete reinforcement; and (14) Characterizing coal solvent extraction processes. Although some of the projects funded did not meet their original goals, the overall objectives of the CPCPC were completed as many new applications for coal-derived feedstocks have been researched. Future research in many of these areas is necessary before implementation into industry.« less

Experimental Insight into the Thermodynamics of the Dissolution of Electrolytes in Room-Temperature Ionic Liquids: From the Mass Action Law to the Absolute Standard Chemical Potential of a Proton

DOE PAGES

Matsubara, Yasuo; Grills, David C.; Koide, Yoshihiro

2016-12-28

Room-temperature ionic liquids (ILs) are a class of nonaqueous solvents that have expanded the realm of modern chemistry, drawing increasing interest over the last few decades, not only in terms of their own unique physical chemistry but also in many applications including organic synthesis, electrochemistry, and biological systems, wherein charged solutes (i.e., electrolytes) often play vital roles. But, our fundamental understanding of the dissolution of an electrolyte in an IL is still rather limited. For example, the activity of a charged species has frequently been assumed to be unity without a clear experimental basis. In this study, we have discussedmore » a standard component-based scheme for the dissolution of an electrolyte in an IL, supported by our observation of ideal Nernstian responses for the reduction of silver and ferrocenium salts in a representative IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim +][NTf 2 -] or [emim +][TFSI -]). Using this scheme, which was also supported by temperature-dependent measurements with ILs having longer alkyl chains in the imidazolium ring, and the solubility of the IL in water, we established the concept of Gibbs transfer energies of “pseudo-single ions” from the IL to conventional neutral molecular solvents (water, acetonitrile, and methanol). This concept, which bridges component- and constituent-based energetics, utilizes an extrathermodynamic assumption, which itself was justified by experimental observations. Furthermore, these energies enable us to eliminate inner potential differences between the IL and molecular solvents (solvent-solvent interactions), that is, on a practical level, conditional liquid junction potential differences, so that we can discuss ion-solvent interactions independently. Specifically, we have examined the standard electrode potential of the ferrocenium/ferrocene redox couple, Fc +/Fc, and the absolute intrinsic standard chemical potential of a proton in [emim +][NTf 2 -], finding that the proton is more acidic in the IL than in water by 6.5 ± 0.6 units on the unified pH scale. Finally, our results strengthen the progress on the physical chemistry of ions in IL solvent systems on the basis of their activities, providing a rigorous thermodynamic framework.« less

Enhancement of dissolution rate of poorly-soluble active ingredients by supercritical fluid processes. Part I: Micronization of neat particles.

PubMed

Perrut, M; Jung, J; Leboeuf, F

2005-01-06

In this first of two articles, we discuss some issues surrounding the dissolution rate enhancement of poorly-soluble active ingredients micronized into nano-particles using several supercritical fluid particle design processes including rapid expansion of supercritical solutions (RESS), supercritical anti-solvent (SAS) and particles from gas-saturated solutions/suspensions (PGSS). Experimental results confirm that dissolution rates do not only depend on the surface area and particle size of the processed powder, but are greatly affected by other physico-chemical characteristics such as crystal morphology and wettability that may reduce the benefit of micronization.

Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

DOE PAGES

Hsieh, Peter Y.; Kwong, Kyei-Sing; Bennett, James

2015-09-27

Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. We measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometermore » and their ash fusion temperatures through optical image analysis. All measurements were made in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. An understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.« less

Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsieh, Peter Y.; Kwong, Kyei-Sing; Bennett, James

Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. We measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometermore » and their ash fusion temperatures through optical image analysis. All measurements were made in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. An understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.« less

Co-processing of carbonaceous solids and petroleum oil

DOEpatents

Gupta, Avinash; Greene, Marvin I.

1992-01-01

In a process for producing distillates from coal by a first stage thermal liquefaction followed by a catalytic hydrogenation, liquefaction solvent is added at points spaced over the length of the thermal liquefaction heater. Coal may be co-processed with petroleum oil by adding pre-hydrogenated oil to the first stage or unhydrogenated oil to the second stage.

Coal desulfurization by low temperature chlorinolysis, phase 3

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Rohatgi, N. K.; Ernest, J.

1981-01-01

Laboratory scale, bench scale batch reactor, and minipilot plant tests were conducted on 22 bituminous, subbituminous, and lignite coals. Chemical pretreatment and post treatment of coals relative to the chlorination were tried as a means of enhancing desulfurization by the chlorinolysis process. Elevated temperature (500-700 C) hydrogen treatment of chlorinolysis-processed coal at atmospheric pressure was found to substantially increase coal desulfurization up to 90 percent. Sulfur forms, proximate and ultimate analyses of the processed coal are included. Minipilot plant operation indicates that the continuous flow reactor provides coal desulfurization results comparable to those obtained in the batch reactor. Seven runs were conducted at coal feed rates of 1.5 to 8.8 kg per hour using water and methylchloroform solvents, gaseous chlorine feed of 3 to 31.4 SCFH at 21 to 70 C, and atmospheric pressure for retention times of 20 to 120 minutes.

Micro- and nano-porous surface patterns prepared by surface-confined directional melt crystallization of solvent

NASA Astrophysics Data System (ADS)

Kim, Byoung Soo; Kim, Hyun Jin; An, Suyeong; Chi, Sangwon; Kim, Junseok; Lee, Jonghwi

2017-07-01

Recently, numerous attempts have been made to engineer micro- and nano-porous surface patterns or to develop convenient preparation methods for the practical applications of self-cleaning surfaces, water-repellent surfaces, novel textures, etc. Herein, we introduce a simple, cheap, and repeatable crystallization-based method to produce porous surface structures, on any surface of already fabricated polymeric materials. Contact of the solvent phase with cooled polymer surfaces enabled the limited dissolution of the surfaces and the subsequent extremely fast melt crystallization of the solvent. After removing the crystals, various micro- and nano-porous patterns were obtained, whose pore sizes ranged over three orders of magnitude. Pore depth was linearly dependent on the dissolution time. Crystal growth was mainly directed normal to the surfaces, but it was also controlled in-plane, resulting in cylindrical or lamellar structures. Superhydrophobic surfaces were successfully prepared on both polystyrene and polycarbonate. This process offers a novel surface engineering tool for a variety of polymer surfaces, whose topology can be conveniently controlled over a wide range by crystal engineering.

Verifying Dissolution Of Wax From Hardware Surfaces

NASA Technical Reports Server (NTRS)

Montoya, Benjamina G.

1995-01-01

Wax removed by cleaning solvent revealed by cooling solution with liquid nitrogen. Such improved procedure and test needed in case of hardware that must be protected by wax during machining or plating but required to be free of wax during subsequent use. Improved cleaning procedure and test take less than 5 minutes. Does not require special skill or equipment and performs at cleaning site. In addition, enables recovery of all cleaning solvent.

Non-steady state partitioning of dry cleaning surfactants between tetrachloroethylene (PCE) and water in porous media.

PubMed

Hoggan, James L; Bae, Keonbeom; Kibbey, Tohren C G

2007-08-15

Trapped organic solvents, in both the vadose zone and below the water table, are frequent sources of environmental contamination. A common source of organic solvent contamination is spills, leaks, and improper solvent disposal associated with dry cleaning processes. Dry cleaning solvents, such as tetrachloroethylene (PCE), are typically enhanced with the addition of surfactants to improve cleaning performance. The objective of this work was to examine the partitioning behavior of surfactants from PCE in contact with water. The relative rates of surfactants partitioning and PCE dissolution are important for modeling the behavior of waste PCE in the subsurface, in that they influence the interfacial tension of the PCE, and how (or if) interfacial tension changes over time in the subsurface. The work described here uses a flow-through system to examine simultaneous partitioning and PCE dissolution in a porous medium. Results indicate that both nonylphenol ethoxylate nonionic surfactants and a sulfosuccinate anionic surfactant partition out of residual PCE much more rapidly than the PCE dissolves, suggesting that in many cases interfacial tension changes caused by partitioning may influence infiltration and distribution of PCE in the subsurface. Non-steady-state partitioning is found to be well-described by a linear driving force model incorporating measured surfactant partition coefficients.

Amorphization of itraconazole by inorganic pharmaceutical excipients: comparison of excipients and processing methods.

PubMed

Grobelny, Pawel; Kazakevich, Irina; Zhang, Dan; Bogner, Robin

2015-01-01

The aim of this study was to investigate the effects of solid carriers and processing routes on the properties of amorphous solid dispersions of itraconazole. Three solid carriers with a range of surface properties were studied, (1) a mesoporous silicate, magnesium aluminum silicate (Neusilin US2), (2) a nonporous silicate of corresponding composition (Veegum) and (3) a non-silicate, inorganic excipient, calcium phosphate dibasic anhydrous (A-TAB). The drug was incorporated via either solvent-deposition or ball milling. Both the maximum drug deposited by solvent-based method that produced an amorphous composite and the time for complete amorphization by co-milling was determined by X-ray powder diffraction (XRPD). Changes in the drug and excipients were monitored by nitrogen adsorption and wettability of the powder. The ability of the excipients to amorphize the drug and enhance its dissolution was related to the powder characteristics. Neusilin provided the fastest amorphization time in the mill and highest drug loading by solvent-deposition, compared with the other two excipients. Solvent-deposition provided greater dissolution enhancement than milling, due to the reduction in Neusilin porosity during high energy milling.This study confirms that substrates as well as the processing routes have notable influence on the drug deposition, amorphization, physical stability and drug in vitro release.

Transferring pharmaceuticals into the gas phase

NASA Astrophysics Data System (ADS)

Christen, Wolfgang; Krause, Tim; Rademann, Klaus

2008-11-01

The dissolution of molecules of biological interest in supercritical carbon dioxide is investigated using pulsed molecular beam mass spectrometry. Due to the mild processing temperatures of most supercritical fluids, their adiabatic expansion into vacuum permits to transfer even thermally very sensitive substances into the gas phase, which is particularly attractive for pharmaceutical and biomedical applications. In addition, supercritical CO2constitutes a chemically inert solvent that is compatible with hydrocarbon-free ultrahigh vacuum conditions. Here, we report on the dissolution and pulsed supersonic jet expansion of caffeine (C8H10N4O2), the provitamin menadione (C11H8O2), and the amino acid derivative l-phenylalanine tert-butyl ester hydrochloride (C6H5CH2CH(NH2)COOC(CH3)3[dot operator]HCl), into vacuum. An on-axis residual gas analyzer is used to monitor the relative amounts of solute and solvent in the molecular beam as a function of solvent densityE The excellent selectivity and sensitivity provided by mass spectrometry permits to probe even trace amounts of solutes. The strong density variation of CO2 close to the critical point results in a pronounced pressure dependence of the relative ion currents of solute and solvent molecules, reflecting a substantial change in solubility.

[Preparation of curcumin-EC sustained-release composite particles by supercritical CO2 anti-solvent technology].

PubMed

Bai, Wei-li; Yan, Ting-yuan; Wang, Zhi-xiang; Huang, De-chun; Yan, Ting-xuan; Li, Ping

2015-01-01

Curcumin-ethyl-cellulose (EC) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading and yield of inclusion complex as evaluation indexes, on the basis of single factor tests, orthogonal experimental design was used to optimize the preparation process of curcumin-EC sustained-release composite particles. The experiments such as drug loading, yield, particle size distribution, electron microscope analysis (SEM) , infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 45 degrees C, crystallization pressure 10 MPa, curcumin concentration 8 g x L(-1), solvent flow rate 0.9 mL x min(-1), and CO2 velocity 4 L x min(-1). Under the optimal conditions, the average drug loading and yield of curcumin-EC sustained-release composite particles were 33.01% and 83.97%, and the average particle size of the particles was 20.632 μm. IR and DSC analysis showed that curcumin might complex with EC. The experiments of in vitro dissolution showed that curcumin-EC composite particles had good sustained-release effect. Curcumin-EC sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

Unconventional Coal in Wyoming: IGCC and Gasification of Direct Coal Liquefaction Residue

NASA Astrophysics Data System (ADS)

Schaffers, William Clemens

Two unconventional uses for Wyoming Powder River Basin coal were investigated in this study. The first was the use of coal fired integrated gasification combined cycle (IGCC) plants to generate electricity. Twenty-eight different scenarios were modeled using AspenPlusRTM software. These included slurry, mechanical and dried fed gasifiers; Wyodak and Green River coals, 0%, 70%, and 90% CO2 capture; and conventional evaporative vs air cooling. All of the models were constructed on a feed basis of 6,900 tons of coal per day on an "as received basis". The AspenPlus RTM results were then used to create economic models using Microsoft RTM Excel for each configuration. These models assumed a 3 year construction period and a 30 year plant life. Results for capital and operating costs, yearly income, and internal rates of return (IRR) were compared. In addition, the scenarios were evaluated to compare electricity sales prices required to obtain a 12% IRR and to determine the effects of a carbon emissions tax on the sales price. The second part of the study investigated the gasification potential of residue remaining from solvent extraction or liquefaction of Powder River Basin Coal. Coal samples from the Decker mine on the Wyoming-Montana border were extracted with tetralin at a temperature of 360°C and pressure of 250 psi. Residue from the extraction was gasified with CO2 or steam at 833°C, 900°C and 975°C at pressures of 0.1 and 0.4 MPa. Product gases were analyzed with a mass spectrometer. Results were used to determine activation energies, reaction order, reaction rates and diffusion effects. Surface area and electron microscopic analyses were also performed on char produced from the solvent extraction residue.

The effect of re-dissolution solvents and HPLC columns on the analysis of mycosporine-like amino acids in the eulittoral macroalgae Prasiola crispa and Porphyra umbilicalis

NASA Astrophysics Data System (ADS)

Karsten, Ulf; Escoubeyrou, Karine; Charles, François

2009-09-01

Many macroalgal species that are regularly exposed to high solar radiation such as the eulittoral green alga Prasiola crispa and the red alga Porphyra umbilicalis synthesize and accumulate high concentrations of mycosporine-like amino acids (MAAs) as UV-sunscreen compounds. These substances are typically extracted with a widely used standard protocol following quantification by various high performance liquid chromatography (HPLC) techniques. However, further preparation steps prior to HPLC analysis as well as different HPLC column types have not been systematically checked regarding separation quality and reproducibility. Therefore pure methanol, distilled water and HPLC eluent were evaluated as re-dissolution solvent for dried Prasiola and Porphyra extracts, which were subsequently analyzed on three reversed-phase C8 and C18 HPLC columns. The data indicate that distilled water and the HPLC eluent gave almost identical peak patterns and MAA contents on the C8 and C18 columns. In contrast, the application of the widely used methanol led to double peaks or even the loss of specific peaks as well as to a strong decline in total MAA amounts ranging from about 35% of the maximum in P. crispa to 80% of the maximum in P. umbilicalis. Consequently, methanol should be avoided as re-dissolution solvent for the HPLC sample preparation. An improved protocol for the MAA analysis in macroalgae in combination with a reliable C18 column is suggested.

High shear mixing granulation of ibuprofen and beta-cyclodextrin: effects of process variables on ibuprofen dissolution.

PubMed

Ghorab, Mohamed K; Adeyeye, Moji Christianah

2007-10-19

The aims of the study were to evaluate the effect of high shear mixer (HSM) granulation process parameters and scale-up on wet mass consistency and granulation characteristics. A mixer torque rheometer (MTR) was employed to evaluate the granulating solvents used (water, isopropanol, and 1:1 vol/vol mixture of both) based on the wet mass consistency. Gral 25 and mini-HSM were used for the granulation. The MTR study showed that the water significantly enhanced the beta-cyclodextrin (beta CD) binding tendency and the strength of liquid bridges formed between the particles, whereas the isopropanol/water mixture yielded more suitable agglomerates. Mini-HSM granulation with the isopropanol/water mixture (1:1 vol/vol) showed a reduction in the extent of torque value rise by increasing the impeller speed as a result of more breakdown of agglomerates than coalescence. In contrast, increasing the impeller speed of the Gral 25 resulted in higher torque readings, larger granule size, and consequently, slower dissolution. This was due to a remarkable rise in temperature during Gral granulation that reduced the isopropanol/water ratio in the granulating solvent as a result of evaporation and consequently increased the beta CD binding strength. In general, the HSM granulation retarded ibuprofen dissolution compared with the physical mixture because of densification and agglomeration. However, a successful HSM granulation scale-up was not achieved due to the difference in the solvent mixture's effect from 1 scale to the other.

Solid-state characterization of mefenamic acid.

PubMed

Panchagnula, Ramesh; Sundaramurthy, Prakash; Pillai, Omathanu; Agrawal, Shrutidevi; Raj, Yasvanth Ashok

2004-04-01

The purpose of this study was to characterize mefenamic acid (MA) from commercial samples and samples crystallized from different solvents. Various techniques used for characterization included microscopy (hot stage microscopy, scanning electron microscopy), intrinsic dissolution rate, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffractometry (pXRD). The commercial samples varied in their crystal habit, thermal behavior, and intrinsic dissolution rate. It was found that the commercial samples were polymorphic Form I, which converted to Form II on heating in a DSC pan. Similarly, compression in an intrinsic dissolution rate (IDR) press resulted in the conversion of Form I to Form II. On the other hand, the samples recrystallized from different solvents under varying conditions yielded different crystal habits. Stirring and degree of supersaturation significantly influenced the crystal habit in all the solvents used in the study. Samples crystallized from ethanol and tetrahydrofuran yielded Form I, which behaved similarly to the commercial samples (M1 and M3). Recrystallization from ethyl acetate at a fast cooling rate yielded Form I, which on melting crystallized to Form II. The form I crystallized from ethyl acetate by fast cooling converted partially to form II on storing at ambient conditions. Forms I and II of MA were enantiotropically related. The results demonstrate the variable material characteristics of the commercial samples of MA and the influence of the crystallizing conditions on the formation of the polymorphs. Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association.

Formulation and performance characterization of radio-sterilized "progestin-only" microparticles intended for contraception.

PubMed

Puthli, Shivanand; Vavia, Pradeep

2009-01-01

The aim of this study was to formulate and characterize a microparticulate system of progestin-only contraceptive. Another objective was to evaluate the effect of gamma radio-sterilization on in vitro and in vivo drug release characteristics. Levonorgestrel (LNG) microspheres were fabricated using poly(lactide-co-glycolide) (PLGA) by a novel solvent evaporation technique. The formulation was optimized for drug/polymer ratio, emulsifier concentration, and process variables like speed of agitation and evaporation method. The drug to polymer ratio of 1:5 gave the optimum encapsulation efficiency. Speed of agitation influenced the spherical shape of the microparticles, lower speeds yielding less spherical particles. The speed did not have a significant influence on the drug payloads. A combination of stabilizers viz. methyl cellulose and poly vinyl alcohol with in-water solvent evaporation technique yielded microparticles without any free drug crystals on the surface. This aspect significantly eliminated the in vitro dissolution "burst effect". The residual solvent content was well within the regulatory limits. The microparticles passed the test for sterility and absence of pyrogens. In vitro dissolution conducted on the product before and after gamma radiation sterilization at 2.5 Mrad indicated no significant difference in the drug release patterns. The drug release followed zero-order kinetics in both static and agitation conditions of dissolution testing. The in vivo studies conducted in rabbits exhibited LNG release up to 1 month duration with drug levels maintained within the effective therapeutic window.

Improved physicochemical characteristics of felodipine solid dispersion particles by supercritical anti-solvent precipitation process.

PubMed

Won, Dong-Han; Kim, Min-Soo; Lee, Sibeum; Park, Jeong-Sook; Hwang, Sung-Joo

2005-09-14

Solid dispersions of felodipine were formulated with HPMC and surfactants by the conventional solvent evaporation (CSE) and supercritical anti-solvent precipitation (SAS) methods. The solid dispersion particles were characterized by particle size, zeta potential, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), solubility and dissolution studies. The effects of the drug/polymer ratio and surfactants on the solubility of felodipine were also studied. The mean particle size of the solid dispersions was 200-250 nm; these had a relatively regular spherical shape with a narrow size distribution. The particle size of the solid dispersions from the CSE method increased at 1 h after dispersed in distilled water. However, the particle sizes of solid dispersions from the SAS process were maintained for 6 h due to the increased solubility of felodipine. The physical state of felodipine changed from crystalline to amorphous during the CSE and SAS processes, confirmed by DSC/XRD data. The equilibrium solubility of the felodipine solid dispersion prepared by the SAS process was 1.5-20 microg/ml, while the maximum solubility was 35-110 microg/ml. Moreover, the solubility of felodipine increased with decreasing drug/polymer ratio or increasing HCO-60 content. The solid dispersions from the SAS process showed a high dissolution rate of over 90% within 2 h. The SAS process system may be used to enhance solubility or to produce oral dosage forms with high dissolution rate.

DISSOLUTION OF ZIRCONIUM AND ALLOYS THEREFOR

DOEpatents

Swanson, J.L.

1961-07-11

The dissolution of zirconium cladding in a water solution of ammonium fluoride and ammonium nitrate is described. The method finds particular utility in processing spent fuel elements for nuclear reactors. The zirconium cladding is first dissolved in a water solution of ammonium fluoride and ammonium nitrate; insoluble uranium and plutonium fiuorides formed by attack of the solvent on the fuel materiai of the fuel element are then separated from the solution, and the fuel materiai is dissolved in another solution.

Solid-state characterization of nevirapine.

PubMed

Sarkar, Mahua; Perumal, O P; Panchagnula, R

2008-09-01

The purpose of this investigation is to characterize nevirapine from commercial samples and samples crystallized from different solvents under various conditions. The solid-state behavior of nevirapine samples was investigated using a variety of complementary techniques such as microscopy (optical, polarized, hot stage microscopy), differential scanning calorimeter, thermogravimetric analysis, Fourier transform infrared spectroscopy and powder X-ray diffractometry. The commercial samples of nevirapine had the same polymorphic crystalline form with an anhedral crystal habit. Intrinsic dissolution of nevirapine was similar for both the commercial batches. Powder dissolution showed pH dependency, with maximum dissolution in acidic pH and there was no significant effect of particle size. The samples recrystallized from different solvent systems with varying polarity yielded different crystal habits. Stirring and degrees of supersaturation influenced the size and shape of the crystals. The recrystallized samples did not produce any new polymorphic form, but weak solvates with varying crystal habit were produced. Recrystallized samples showed differences in the x-ray diffractograms. However, all the samples had the same internal crystal lattice as revealed from their similar melting points and heat of fusion. The intrinsic dissolution rate of recrystallized samples was lower than the commercial sample. It was found that the compression pressure resulted in desolvation and partial conversion of the crystal form. After compression, the recrystallized samples showed similar x-ray diffractograms to the commercial sample. Amorphous form showed slightly higher aqueous solubility than the commercial crystalline form.

Source and Cycling of Trace Metals and Nutrients in a Microbial Coalbed Methane System

NASA Astrophysics Data System (ADS)

Earll, M. M.; Barnhart, E. P.; Ritter, D.; Vinson, D. S.; Orem, W. H.; Vengosh, A.; McIntosh, J. C.

2015-12-01

The source and cycling of trace metals and nutrients in coalbed methane (CBM) systems are controlled by both geochemical processes, such as dissolution or precipitation, and biological mediation by microbial communities. CBM production by the microbes is influenced by trace metals and macronutrients such as nitrogen (N) and phosphate (P). Previous studies have shown the importance of these nutrients to both enhance and inhibit methane production; however, it's not clear whether they are sourced from coal via in-situ biodegradation of organic matter or transported into the seams with groundwater recharge. To address this knowledge gap, trace metal and nutrient geochemistry and the organic content of solid coal and associated groundwater will be investigated across a hydrologic gradient in CBM wells in the Powder River Basin, MT. Sequential dissolution experiments (chemical extraction of organic and inorganic constituents) using 8 core samples of coal and sandstone will provide insight into the presence of trace metals and nutrients in coalbeds, the associated minerals present, and their mobilization. If significant concentrations of N, P, and trace metals are present in core samples, in-situ sourcing of nutrients by microbes is highly probable. The biogeochemical evolution of groundwater, as it relates to trace metal and nutrient cycling by microbial consortia, will be investigated by targeting core-associated coal seams from shallow wells in recharge areas to depths of at least 165 m and across a 28 m vertical profile that include overburden, coal, and underburden. If microbial-limiting trace metals and nutrients are transported into coal seams with groundwater recharge, we would expect to see higher concentrations of trace metals and nutrients in recharge areas compared to deeper coalbeds. The results of this study will provide novel understanding of where trace metals and nutrients are sourced and how they are cycled in CBM systems.

Catalysts and process developments for two-stage liquefaction. Third quarterly technical progress report No. 44, April 1, 1991--June 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cronauer, D.C.; Swanson, A.J.; Sajkowski, D.J.

Research under way in this project centers upon developing and evaluating catalysts and process improvements for coal liquefaction in the two-stage close-coupled catalytic process. As documented in the previous quarterly report (Task 3.1), there was little advantage for presoaking Black Thunder coal or Martin Lake lignite in a hydrogen-donor solvent, such as tetralin, at temperatures up to 600{degrees}F prior to liquefaction at higher temperatures. The amount of decarboxylation that occurred during the presoaking of Black Thunder coal or Martin Lake lignite in tetralin in the temperature range of 400 to 600{degrees}F was also relatively small. Further experimentation was undertaken inmore » a continuous flow unit with Black Thunder coal, where the primary goal was to determine the extent of decarboxylation and changes in the structure of the unconverted coal samples. The preliminary results indicated little conversion of the feed coal to THF solubles at 600{degrees}F, although the conversion did increase with increasing temperature up to 24% at 700{degrees}F. The level of decarboxylation was also low at the above reaction temperatures. Thus, presoaking in a coal-derived solvent or even tetralin does not seem to be an effective means to achieve decarboxylation. A suitable sample of Illinois No. 6 coal was received and tested for liquefaction. The batch liquefaction showed that this sample had good reactivity. The continuous liquefaction test was done in a two-stage unit with AMOCAT{trademark}-1C catalyst in both reactors. A significant amount of resid was produced throughout this three-week run. As the catalyst aged, the distillate production decreased and its product quality got worse. The feedstock liquefaction studies for the three feedstocks (Black Thunder subbituminous coal, Martin Lake lignite, and Illinois No. 6 coal) have been completed, and their results will be compared in a subsequent quarterly report.« less

Using ground and intact coal Samples to evaluate hydrocarbon fate during supercritical CO2 injection into coal beds: effects of particle size and coal moisture

USGS Publications Warehouse

Kolak, Jon; Hackley, Paul C.; Ruppert, Leslie F.; Warwick, Peter D.; Burruss, Robert

2015-01-01

To investigate the potential for mobilizing organic compounds from coal beds during geologic carbon dioxide (CO2) storage (sequestration), a series of solvent extractions using dichloromethane (DCM) and using supercritical CO2 (40 °C and 10 MPa) were conducted on a set of coal samples collected from Louisiana and Ohio. The coal samples studied range in rank from lignite A to high volatile A bituminous, and were characterized using proximate, ultimate, organic petrography, and sorption isotherm analyses. Sorption isotherm analyses of gaseous CO2 and methane show a general increase in gas storage capacity with coal rank, consistent with findings from previous studies. In the solvent extractions, both dry, ground coal samples and moist, intact core plug samples were used to evaluate effects of variations in particle size and moisture content. Samples were spiked with perdeuterated surrogate compounds prior to extraction, and extracts were analyzed via gas chromatography–mass spectrometry. The DCM extracts generally contained the highest concentrations of organic compounds, indicating the existence of additional hydrocarbons within the coal matrix that were not mobilized during supercritical CO2 extractions. Concentrations of aliphatic and aromatic compounds measured in supercritical CO2 extracts of core plug samples generally are lower than concentrations in corresponding extracts of dry, ground coal samples, due to differences in particle size and moisture content. Changes in the amount of extracted compounds and in surrogate recovery measured during consecutive supercritical CO2extractions of core plug samples appear to reflect the transition from a water-wet to a CO2-wet system. Changes in coal core plug mass during supercritical CO2 extraction range from 3.4% to 14%, indicating that a substantial portion of coal moisture is retained in the low-rank coal samples. Moisture retention within core plug samples, especially in low-rank coals, appears to inhibit accessibility of supercritical CO2 to coal matrix porosity, limiting the extent to which hydrocarbons are mobilized. Conversely, the enhanced recovery of some surrogates from core plugs relative to dry, ground coal samples might indicate that, once mobilized, supercritical CO2 is capable of transporting these constituents through coal beds. These results underscore the need for using intact coal samples, and for better characterization of forms of water in coal, to understand fate and transport of organic compounds during supercritical CO2 injection into coal beds.

Water-Lean Solvents for Post-Combustion CO 2 Capture: Fundamentals, Uncertainties, Opportunities, and Outlook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heldebrant, David J.; Koech, Phillip K.; Glezakou, Vassiliki-Alexandra

Capturing CO2 from the exhaust of coal-fired power plants is a daunting task, requiring selective removal from a dilute gas stream of millions of pounds per hour of a molecule that is considered thermodynamically and kinetically stable. There are commercial solvent technologies containing proprietary blends of aqueous amines such as Econamine FG+, KS-1, Oase® Blue, and Cansolv that may achieve this task, though only one of them has been deployed at scale, albeit in the natural gas industry.1 The Achilles’ heel of amine blends is the energy loss involved with regenerating the solvent, i.e., boiling and condensing millions of poundsmore » of water per hour. This energy loss translates to a sizeable parasitic load on a coal-fired plant, requiring the plant to burn more coal to get back to its nameplate capacity.2 Unsurprisingly, a considerable amount of research has focused on the design of more efficient technologies to lessen this parasitic load. Liquid systems are the lowest hanging fruit from a time and cost perspective, as they have the potential to use aqueous amine infrastructure, with potential for more rapid ascent up the development ladder than porous solids or membranes.« less

A novel organic solvent-based coupling method for the preparation of covalently immobilized proteins on gold.

PubMed Central

Parker, M. C.; Patel, N.; Davies, M. C.; Roberts, C. J.; Tendler, S. J.; Williams, P. M.

1996-01-01

A novel organic solvent-based coupling method has been developed for the covalent immobilization of biological material to gold surfaces. The method employs the polar organic solvent anhydrous 2,2,2-trifluoroethanol as the reaction medium and involves dissolution of the protein (catalase) in the solvent allowing protein coupling to proceed under basic conditions in a dry organic environment. The advantage of this method is that protein attachment is favored over hydrolysis of the coupling reagent. We have shown qualitatively and quantitatively that following attachment to the gold surface a significant proportion of the enzyme catalase remains catalytically active (at least 20-31%). PMID:8931151

Iron dissolution of dust source materials during simulated acidic processing: the effect of sulfuric, acetic, and oxalic acids.

PubMed

Chen, Haihan; Grassian, Vicki H

2013-09-17

Atmospheric organic acids potentially display different capacities in iron (Fe) mobilization from atmospheric dust compared with inorganic acids, but few measurements have been made on this comparison. We report here a laboratory investigation of Fe mobilization of coal fly ash, a representative Fe-containing anthropogenic aerosol, and Arizona test dust, a reference source material for mineral dust, in pH 2 sulfuric acid, acetic acid, and oxalic acid, respectively. The effects of pH and solar radiation on Fe dissolution have also been explored. The relative capacities of these three acids in Fe dissolution are in the order of oxalic acid > sulfuric acid > acetic acid. Oxalate forms mononuclear bidentate ligand with surface Fe and promotes Fe dissolution to the greatest extent. Photolysis of Fe-oxalate complexes further enhances Fe dissolution with the concomitant degradation of oxalate. These results suggest that ligand-promoted dissolution of Fe may play a more significant role in mobilizing Fe from atmospheric dust compared with proton-assisted processing. The role of atmospheric organic acids should be taken into account in global-biogeochemical modeling to better access dissolved atmospheric Fe deposition flux at the ocean surface.

Optimized Solvent for Energy-Efficient, Environmentally-Friendly Capture of CO{sub 2} at Coal-Fired Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farthing, G. A.; Rimpf, L. M.

The overall goal of this project, as originally proposed, was to optimize the formulation of a novel solvent as a critical enabler for the cost-effective, energy-efficient, environmentally-friendly capture of CO{sub 2} at coal-fired utility plants. Aqueous blends of concentrated piperazine (PZ) with other compounds had been shown to exhibit high rates of CO{sub 2} absorption, low regeneration energy, and other desirable performance characteristics during an earlier 5-year development program conducted by B&W. The specific objective of this project was to identify PZ-based solvent formulations that globally optimize the performance of coal-fired power plants equipped with CO{sub 2} scrubbing systems. Whilemore » previous solvent development studies have tended to focus on energy consumption and absorber size, important issues to be sure, the current work seeks to explore, understand, and optimize solvent formulation across the full gamut of issues related to commercial application of the technology: capital and operating costs, operability, reliability, environmental, health and safety (EH&S), etc. Work on the project was intended to be performed under four budget periods. The objective of the work in the first budget period has been to identify several candidate formulations of a concentrated PZ-based solvent for detailed characterization and evaluation. Work in the second budget period would generate reliable and comprehensive property and performance data for the identified formulations. Work in the third budget period would quantify the expected performance of the selected formulations in a commercial CO{sub 2} scrubbing process. Finally, work in the fourth budget period would provide a final technology feasibility study and a preliminary technology EH&S assessment. Due to other business priorities, however, B&W has requested that this project be terminated at the end of the first budget period. This document therefore serves as the final report for this project. It is the first volume of the two-volume final report and summarizes Budget Period 1 accomplishments under Tasks 1-5 of the project, including the selection of four solvent formulations for further study.« less

Freeze drying for morphological control of inter-penetrating polymer networks

NASA Technical Reports Server (NTRS)

Hansen, Marion G.; Pater, Ruth H.

1990-01-01

The intrinsic brittleness of BMI resins can be reduced through the creation of an interpenetrating network (IPN) of BMI with a reactive-encapped thermoplastic, such as the presently considered polyimidesulfone, PISO2. The PISO2 and BMI were dissolved in a common solvent, which was then removed from the constituents by freeze drying; in an alternative method, an IPN was formed through dissolution of the constituent in a common solvent with either high or low melting point, followed by evaporative removal of the solvent. The effectiveness of the freeze-drying approach for morphological control is evaluated.

DEVELOPMENT OF CONTINUOUS SOLVENT EXTRACTION PROCESSES FOR COAL DERIVED CARBON PRODUCTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliot B. Kennel; Chong Chen; Dady Dadyburjor

2005-04-13

The purpose of this DOE-funded effort is to develop continuous processes for solvent extraction of coal for the production of carbon products. These carbon products include materials used in metals smelting, especially in the aluminum and steel industries, as well as porous carbon structural material referred to as ''carbon foam'' and carbon fibers. Table 1 provides an overview of the major markets for carbon products. Current sources of materials for these processes generally rely on petroleum distillation products or coal tar distillates obtained as a byproduct of metcoke production facilities. In the former case, the American materials industry, just asmore » the energy industry, is dependent upon foreign sources of petroleum. In the latter case, metcoke production is decreasing every year due to the combined difficulties associated with poor economics and a significant environmental burden. Thus, a significant need exists for an environmentally clean process which can used domestically obtained raw materials and which can still be very competitive economically.« less

Solubility and dissolution thermodynamics of tetranitroglycoluril in organic solvents at 295-318 K

NASA Astrophysics Data System (ADS)

Zheng, Zhihua; Wang, Jianlong; Hu, Zhiyan; Du, Hongbin

2017-08-01

The solubility data of tetranitroglycoluril in acetone, methanol, ethanol, ethyl acetate, nitromethane and chloroform at temperatures ranging from 295-318 K were measured by gravimetric method. The solubility data of tetranitroglycoluril were fitted with Apelblat semiempirical equation. The dissolution enthalpy, entropy and Gibbs energy of tetranitroglycoluril were calculated using the Van't Hoff and Gibbs equations. The results showed that the Apelblat semiempirical equation was significantly correlated with solubility data. The dissolving process was endothermic, entropy-driven, and nonspontaneous.

Using Advanced Analysis Approaches to Complete Long-Term Evaluations of Natural Attenuation Processes on the Remediation of Dissolved Chlorinated Solvent Contamination

DTIC Science & Technology

2008-10-01

and UTCHEM (Clement et al., 1998). While all four of these software packages use conservation of mass as the basic principle for tracking NAPL...simulate dissolution of a single NAPL component. UTCHEM can be used to simulate dissolution of a multiple NAPL components using either linear or first...parameters. No UTCHEM a/ 3D model, general purpose NAPL simulator. Yes Virulo a/ Probabilistic model for predicting leaching of viruses in unsaturated

Energetics of the molecular interactions of L-alanine and L-serine with xylitol, D-sorbitol, and D-mannitol in aqueous solutions at 298.15 K

NASA Astrophysics Data System (ADS)

Mezhevoi, I. N.; Badelin, V. G.

2013-04-01

Integral enthalpies of dissolution Δsol H m of L-alanine and L-serine are measured via the calorimetry of dissolution in aqueous solutions of xylitol, D-sorbitol, and D-mannitol. Standard enthalpies of dissolution (Δsol H ○) and the transfer (Δtr H ○) of amino acids from water to binary solvent are calculated from the experimental data. Using the McMillan-Mayer theory, enthalpy coefficients of pairwise interactions h xy of amino acids with molecules of polyols are calculated that are negative. The obtained results are discussed within the theory of the prevalence of different types of interactions in mixed solutions and the effect of the structural features of interacting biomolecules on the thermochemical parameters of dissolution of amino acids.

In situ fabrication of electrochemically grown mesoporous metallic thin films by anodic dissolution in deep eutectic solvents.

PubMed

Renjith, Anu; Roy, Arun; Lakshminarayanan, V

2014-07-15

We describe here a simple electrodeposition process of forming thin films of noble metallic nanoparticles such as Au, Ag and Pd in deep eutectic solvents (DES). The method consists of anodic dissolution of the corresponding metal in DES followed by the deposition on the cathodic surface. The anodic dissolution process in DES overcomes the problems associated with copious hydrogen and oxygen evolution on the electrode surface when carried out in aqueous medium. The proposed method utilizes the inherent abilities of DES to act as a reducing medium while simultaneously stabilizing the nanoparticles that are formed. The mesoporous metal films were characterized by SEM, XRD and electrochemical techniques. Potential applications of these substrates in surface enhanced Raman spectroscopy and electrocatalysis have been investigated. A large enhancement of Raman signal of analyte was achieved on the mesoporous silver substrate after removing all the stabilizer molecules from the surface by calcination. The highly porous texture of the electrodeposited film provides superior electro catalytic performance for hydrogen evolution reaction (HER). The mechanisms of HER on the fabricated substrates were studied by Tafel analysis and electrochemical impedance spectroscopy (EIS). Copyright © 2014 Elsevier Inc. All rights reserved.

Chelant-enhanced washing of CCA-contaminated soil: Coupled with selective dissolution or soil stabilization.

PubMed

Beiyuan, Jingzi; Lau, Abbe Y T; Tsang, Daniel C W; Zhang, Weihua; Kao, Chih-Ming; Baek, Kitae; Ok, Yong Sik; Li, Xiang-Dong

2018-01-15

Remediation of CCA-contaminated soil (Cr, Cu, and As) by biodegradable chelant-enhanced washing (EDDS, S,S-ethylene-diamine-disuccinic-acid) needs further enhancement. This study investigated the effectiveness of coupling with pre-treatment by selective dissolution and post-treatment by soil amendments, respectively. Three groups of reagents (reductants, alkaline solvents, and organic ligands) were adopted in the pre-treatment to dissolve the oxide minerals before EDDS extraction. In the post-treatment, soil amendments (coal fly ash (CFA), acid mine drainage sludge (AMDS), green waste compost (GWC)), and their mixtures) were used for a 2-month stabilization after 2-h EDDS washing. Multi-endpoint evaluation was performed by assessing the chemical state, leachability, mobility, bioaccessibility, and plant-availability of residual metal(loid)s as well as the cytotoxicity, enzyme activities, and available nutrients of the treated soils. Pre-treatment by dithionite-citrate-bicarbonate significantly enhanced extraction efficiency, but also increased the leachability of As and Cr and bioaccessibility of Cr in the treated soils. While sodium hydroxide removed the majority of As without increasing its leachability and bioaccessibility, it increased the cytotoxicity and inhibited the acid phosphatase activity. Post-treatment with AMDS and CFA effectively controlled the mobility and leachability of residual As and Cr after EDDS washing. However, destabilized Cu was only marginally immobilized by GWC due to strong Cu-EDDS complexation. The bioaccessibility and phytoavailability of Cu was primarily reduced by EDDS washing, while those of As and Cr could be attenuated by AMDS and CFA. This study indicates that coupling chemical extraction with subsequent soil amendment plays complementary roles in mitigating effects of residual metal(loid)s and improving environmental quality. Copyright © 2017 Elsevier B.V. All rights reserved.

Impacts of detrital nano- and micro-scale particles (dNP) on contaminant dynamics in a coal mine AMD treatment system.

PubMed

Lefticariu, Liliana; Sutton, Stephen R; Bender, Kelly S; Lefticariu, Mihai; Pentrak, Martin; Stucki, Joseph W

2017-01-01

Pollutants in acid mine drainage (AMD) are usually sequestered in neoformed nano- and micro-scale particles (nNP) through precipitation, co-precipitation, and sorption. Subsequent biogeochemical processes may control nNP stability and thus long-term contaminant immobilization. Mineralogical, chemical, and microbiological data collected from sediments accumulated over a six-year period in a coal-mine AMD treatment system were used to identify the pathways of contaminant dynamics. We present evidence that detrital nano- and micron-scale particles (dNP), composed mostly of clay minerals originating from the partial weathering of coal-mine waste, mediated biogeochemical processes that catalyzed AMD contaminant (1) immobilization by facilitating heterogeneous nucleation and growth of nNP in oxic zones, and (2) remobilization by promoting phase transformation and reductive dissolution of nNP in anoxic zones. We found that dNP were relatively stable under acidic conditions and estimated a dNP content of ~0.1g/L in the influent AMD. In the AMD sediments, the initial nNP precipitates were schwertmannite and poorly crystalline goethite, which transformed to well-crystallized goethite, the primary nNP repository. Subsequent reductive dissolution of nNP resulted in the remobilization of up to 98% of S and 95% of Fe accompanied by the formation of a compact dNP layer. Effective treatment of pollutants could be enhanced by better understanding the complex, dynamic role dNP play in mediating biogeochemical processes and contaminant dynamics at coal-mine impacted sites. Copyright © 2016 Elsevier B.V. All rights reserved.

Thermodynamic Parameters of the Dissolution of 4-Hydroxy-L-Proline and L-Phenylalanine in Mixed Aqueous Solvents at 298 K

NASA Astrophysics Data System (ADS)

Smirnov, V. I.; Badelin, V. G.

2018-01-01

The enthalpies of solution of 4-hydroxy-L-proline and L-phenylalanine in binary mixed aqueous solvents containing acetonitrile (AN), 1,4-dioxane (1,4-DO), or acetone (AC) at mole fractions of 0 to 0.25 are determined at T = 298.15 K via isothermal calorimetry. The standard enthalpies of solution (Δsol H°) and transfer (Δtr H°) of 4-hydroxy-L-proline and L-phenylalanine from water to mixed aqueous solvents are calculated using the experimental calorimetric data, as are the enthalpy coefficients of paired interactions ( h xy ) between the molecules of the investigated amino acids and the organic solvents. The effects the mixed aqueous solvent composition and the structure of the organic solvent molecules have on the enthalpies of solution and transfer for the investigated amino acids are considered. The correlation between the enthalpy of solution of the amino acids and the electron-donating properties of the organic solvents in the mixed aqueous solvent systems is established.

Application of enzyme-linked immunosorbent assay for measurement of polychlorinated biphenyls from hydrophobic solutions: Extracts of fish and dialysates of semipermeable membrane devices: Chapter 26

USGS Publications Warehouse

Zajicek, James L.; Tillitt, Donald E.; Huckins, James N.; Petty, Jimmie D.; Potts, Michael E.; Nardone, David A.

1996-01-01

Determination of PCBs in biological tissue extracts by enzyme-linked immunosorbent assays (ELISAs) can be problematic, since the hydrophobic solvents used for their extraction and isolation from interfering biochemicals have limited compatibility with the polar solvents (e.g. methanol/water) and the immunochemical reagents used in ELISA. Our studies of these solvent effects indicate that significant errors can occur when microliter volumes of PCB containing extracts, in hydrophobic solvents, are diluted directly into methanol/water diluents. Errors include low recovery and excess variability among sub-samples taken from the same sample dilution. These errors are associated with inhomogeneity of the dilution, which is readily visualized by the use of a hydrophobic dye, Solvent Blue 35. Solvent Blue 35 is also used to visualize the evaporative removal of hydrophobic solvent and the dissolution of the resulting PCB/dye residue by pure methanol and 50% (v/v) methanol/water, typical ELISA diluents. Evaporative removal of isooctane by an ambient temperature nitrogen purge with subsequent dissolution in 100% methanol gives near quantitative recovery of model PCB congeners. We also compare concentrations of total PCBs from ELISA (ePCB) to their corresponding concentrations determined from capillary gas chromatography (GC) in selected fish sample extracts and dialysates of semipermeable membrane device (SPMD) passive samplers using an optimized solvent exchange procedure. Based on Aroclor 1254 calibrations, ePCBs (ng/mL) determined in fish extracts are positively correlated with total PCB concentrations (ng/mL) determined by GC: ePCB = 1.16 * total-cPCB - 5.92. Measured ePCBs (ng/3 SPMDs) were also positively correlated (r2 = 0.999) with PCB totals (ng/3 SPMDs) measured by GC for dialysates of SPMDs: ePCB = 1.52 * total PCB - 212. Therefore, this ELISA system for PCBs can be a rapid alternative to traditional GC analyses for determination of PCBs in extracts of biota or in SPMD dialysates.

Evaluations in support of regulatory and research decisions by the U. S. Environmental Protection Agency for the control of toxic hazards from hazardous wastes, glyphosate, dalapon, and synthetic fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scofield, R.

1984-01-01

This report includes toxicological and regulatory evaluations performed in support of U.S. EPA regulation of toxic materials and hazardous wastes. The first section of the report describes evaluations which support: (a) the regulation of small-volume generators of hazardous wastes, (b) the regulation of hazardous wastes from pesticide manufacturing, and (c) the disposal of the herbicide, silvex. The second section describes the environmental fate, transport, and effect of glyphosate and dalapon. The third section deals with synthetic fuels, including evaluations of synfuel-product toxicity, uncontrolled air emissions, and particular focus on the toxicity of products from several indirect coal liquefaction processes includingmore » methanol synthesis, Fischer-Tropsch, Mobil M-Gasoline, and Lurgi gasification technologies. Three direct coal liquefaction processes were examined for product toxicity and air emissions: Solvent Refined Coal (I and II) and the Exxon Donor Solvent Process. Also described in the third section is an evaluation of environmental and health hazards associated with the use of synthetic fuels from indirect coal liquefaction, direct coal liquefaction, and shale oil. Finally, the fourth section discusses some problems associated with performing, on a contractual basis, scientific and technical evaluations in support of U.S. EPA regulatory and research decisions.« less

Removing micron size particles from coal liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, B.R.; Westmoreland, P.R.

This paper reports results of an investigation which was undertaken in order to improve purification of liquid fuels obtained by coal liquefaction processes. It is shown that settling and filtration rates increased substantially after agglomeration. And, ground coal was found to be an economical substitute for diatomaceous earth in filtration. The effects of certain solvents on the agglomerating tendencies of solids in the unfiltered oil (UFO) from the SRC and COED processes were determined by oil immersion microscopy. The significant results obtained by these experiments are listed. Economic advantages are presented. 13 references.

Separation of aromatic carboxylic acids using quaternary ammonium salts on reversed-phase HPLC. 2. Application for the analysis of Loy Yang coal oxidation products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawamura, K.; Okuwaki, A.; Verheyen, T.V.

In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed-phase HPLC using eluent containing quaternary ammonium salt was optimized using the solvent gradient method. This method was applied for the analysis of Loy Yang coal oxidation products. It was confirmed that the analytical data using this method were consistent with those determined using gas chromatography.

Coal desulfurization by low temperature chlorinolysis, phase 2

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Grohmann, K.; Rohatgi, N.; Ernest, J.; Feller, D.

1980-01-01

An engineering scale reactor system was constructed and operated for the evaluation of five high sulfur bituminous coals obtained from Kentucky, Ohio, and Illinois. Forty-four test runs were conducted under conditions of 100 by 200 mesh coal,solvents - methlychloroform and water, 60 to 130 C, 0 to 60 psig, 45 to 90 minutes, and gaseous chlorine flow rate of up to 24 SCFH. Sulfur removals demonstrated for the five coals were: maximum total sulfur removal of 46 to 89% (4 of 5 coals with methylchloroform) and 0 to 24% with water. In addition, an integrated continuous flow mini-pilot plant was designed and constructed for a nominal coal rate of 2 kilograms/hour which will be operated as part of the follow-on program. Equipment flow sheets and design drawings are included for both the batch and continuous flow mini-pilot plants.

Temporal dissolution of potentially toxic elements from silver smelting slag by synthetic environmental solutions.

PubMed

Ash, Christopher; Borůvka, Luboš; Tejnecký, Václav; Šebek, Ondřej; Nikodem, Antonín; Drábek, Ondřej

2013-11-15

Waste slag which is created during precious metal smelting contains high levels of potentially toxic elements (PTE) which can be mobilised from unconfined deposits into the local environment. This paper examines the extractability of selected PTE (Pb, Zn, Cd, Mn) from slag samples by synthetic solutions designed to replicate those in the environment. Extracting agents were used to replicate potential leaching scenarios which are analogous to natural chemical weathering. Slag was submersed in a rainwater simulation solution (RSS), weak citric acid solution (representing rhizosphere secretions) and control solutions (deionised water) for a one month period with solution analyses made at intervals of 1, 24, 168 and 720 h. In 1 mM citric acid, dissolution of Cd and Zn showed little change with time, although for Zn the initial dissolution was considerable. Lead in citric acid was characterized by overall poor extractability. Mn solubility increased until an equilibrium state occurred within 24 h. The solubility of studied metals in citric acid can be characterized by a short time to equilibrium. RSS proved to be an effective solvent that, unlike citric acid solution, extracted increasing concentrations of Cd, Mn and Zn with time. Solubility of Pb in RSS was again very low. When taken as a proportion of a single 2 M HNO3 extraction which was applied to slag samples, Cd was the element most readily leached into RSS and control samples. In both studied solvents, slag heterogeneity is prominent in the case of Cd and Zn solubility. Contact time with solvent appears to be an important variable for the release of PTE from slag into solution. The purpose of this study was to provide insight into the environmental chemical dissolution of PTE from slag, which causes their enrichment in surrounding soils and surface waters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preparation, characterization and in vitro evaluation of solid dispersions containing docetaxel.

PubMed

Chen, Jie; Qiu, Liyan; Hu, Minxin; Jin, Yi; Han, Jieru

2008-06-01

Solid dispersions using water-soluble carriers were studied for improving the dissolution of docetaxel, a poorly soluble compound. In order to obtain the most optimized formulation, we prepared many solid dispersions with different carriers, different solvents, or at a series of drug-to-carrier ratios, and compared their dissolution. The accumulative dissolution of docetaxel from poloxamer 188 was more excellent than that from PVP(k30) and glyceryl monostearate, and the dissolution of docetaxel from solid dispersion was markedly higher than that of pure docetaxel; meanwhile the increased dissolution was partly dependent on the ratios of docetaxel and poloxamer 188. The ethanol used to prepare solid dispersion is of more significant effect on the dissolution of docetaxel than that of acetone. The docetaxel/poloxamer 188 system was characterized by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and environmental scanning electron microscope (ESEM). The results of DSC, XRD, and ESEM analyses of docetaxel/poloxamer 188 system showed that there are intermolecular interactions between docetaxel and poloxamer, and the crystallinity of docetaxel disappeared. These results show that solid dispersion is a promising approach of developing docetaxel drug formulates.

Revisiting the Corrosion of the Aluminum Current Collector in Lithium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Tianyuan; Xu, Gui-Liang; Li, Yan

The corrosion of aluminum current collectors and the oxidation of solvents at a relatively high potential have been widely investigated with an aim to stabilize the electrochemical performance of lithium-ion batteries using such components. The corrosion behavior of aluminum current collectors was revisited using a home-build high-precision electrochemical measurement system, and the impact of electrolyte components and the surface protection layer on aluminum foil was systematically studied. The electrochemical results showed that the corrosion of aluminum foil was triggered by the electrochemical oxidation of solvent molecules, like ethylene carbonate, at a relative high potential. The organic radical cations generated frommore » the electrochemical oxidation are energetically unstable, and readily undergo a deprotonation reaction that generates protons and promote the dissolution of Al3+ from the aluminum foil. This new reaction mechanism can also shed light on the dissolution of transitional metal at high potentials.« less

Revisiting the Corrosion of the Aluminum Current Collector in Lithium-Ion Batteries

DOE PAGES

Ma, Tianyuan; Xu, Gui -Liang; Li, Yan; ...

2017-02-16

The corrosion of aluminum current collectors and the oxidation of solvents at a relatively high potential have been widely investigated with an aim to stabilize the electrochemical performance of lithium-ion batteries using such components. The corrosion behavior of aluminum current collectors was revisited using a home-build high-precision electrochemical measurement system, and the impact of electrolyte components and the surface protection layer on aluminum foil was systematically studied. The electrochemical results showed that the corrosion of aluminum foil was triggered by the electrochemical oxidation of solvent molecules, like ethylene carbonate, at a relative high potential. The organic radical cations generated frommore » the electrochemical oxidation are energetically unstable, and readily undergo a deprotonation reaction that generates protons and promote the dissolution of Al 3+ from the aluminum foil. Finally, this new reaction mechanism can also shed light on the dissolution of transitional metal at high potentials.« less

Selective dissolution of halide perovskites as a step towards recycling solar cells

NASA Astrophysics Data System (ADS)

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

2016-05-01

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

Revisiting the Corrosion of the Aluminum Current Collector in Lithium-Ion Batteries.

PubMed

Ma, Tianyuan; Xu, Gui-Liang; Li, Yan; Wang, Li; He, Xiangming; Zheng, Jianming; Liu, Jun; Engelhard, Mark H; Zapol, Peter; Curtiss, Larry A; Jorne, Jacob; Amine, Khalil; Chen, Zonghai

2017-03-02

The corrosion of aluminum current collectors and the oxidation of solvents at a relatively high potential have been widely investigated with an aim to stabilize the electrochemical performance of lithium-ion batteries using such components. The corrosion behavior of aluminum current collectors was revisited using a home-build high-precision electrochemical measurement system, and the impact of electrolyte components and the surface protection layer on aluminum foil was systematically studied. The electrochemical results showed that the corrosion of aluminum foil was triggered by the electrochemical oxidation of solvent molecules, like ethylene carbonate, at a relative high potential. The organic radical cations generated from the electrochemical oxidation are energetically unstable and readily undergo a deprotonation reaction that generates protons and promotes the dissolution of Al 3+ from the aluminum foil. This new reaction mechanism can also shed light on the dissolution of transitional metal at high potentials.

Comparison and Characterisation of Regenerated Chitosan from 1-Butyl-3-methylimidazolium Chloride and Chitosan from Crab Shells

PubMed Central

Arnold, Lyndon

2015-01-01

Chitosan is a biopolymer derived from chitin which is naturally occurring in the exoskeleton of crustaceans. This paper reports dissolution and regeneration of chitosan by directly dissolving in an ionic liquid solvent, 1-butyl-3-methylimidazolium chloride (BMIMCl). This will provide an ideal platform to solubilise these kinds of polymers to achieve the dissolution. The current study dissolved chitosan from crab shell utilising BMIMCl as a solvent and characterised the resultant regenerated polymer. The regenerated chitosan showed increased hydrogen bonding when characterised by Fourier transform infrared (FTIR) spectral analysis. In addition, the study also compared the characteristics of regenerated and generic chitosan. The regenerated chitosan was also evaluated for antimicrobial properties and showed to possess antibacterial features similar to the commercial grade. This method can be utilised in future for blending of polymers with chitosan in a dissolved phase. PMID:26090452

Selective dissolution of halide perovskites as a step towards recycling solar cells.

PubMed

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

2016-05-23

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb(2+) cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

Revisiting the Corrosion of the Aluminum Current Collector in Lithium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Tianyuan; Xu, Gui -Liang; Li, Yan

The corrosion of aluminum current collectors and the oxidation of solvents at a relatively high potential have been widely investigated with an aim to stabilize the electrochemical performance of lithium-ion batteries using such components. The corrosion behavior of aluminum current collectors was revisited using a home-build high-precision electrochemical measurement system, and the impact of electrolyte components and the surface protection layer on aluminum foil was systematically studied. The electrochemical results showed that the corrosion of aluminum foil was triggered by the electrochemical oxidation of solvent molecules, like ethylene carbonate, at a relative high potential. The organic radical cations generated frommore » the electrochemical oxidation are energetically unstable, and readily undergo a deprotonation reaction that generates protons and promote the dissolution of Al 3+ from the aluminum foil. Finally, this new reaction mechanism can also shed light on the dissolution of transitional metal at high potentials.« less

Preparation and in vitro/in vivo Evaluation of Lacidipine by Adsorption onto Fumed Silica Using Supercritical Carbon Dioxide.

PubMed

Geng, Yajie; Fu, Qiang; Guo, Bei; Li, Yun; Zhang, Xiangrong; Wang, Xianglin; Zhang, Tianhong

2016-01-01

The aim of this study was to design a silica-supported solid dispersion of lacidipine (LCDP) to enhance the dissolution rate and oral absorption using supercritical CO2 (scCO2) as a solvent. The formulation was characterized using differential scanning calorimetry, powder X-ray diffraction, scanning electron microscopy and fourier transformed infrared spectroscopy. In the dissolution test, LCDP-scCO2 formulation showed a significantly enhanced dissolution compared with LCDPsilica physical mixture and a faster dissolution rate than Lacipil® under different dissolution conditions. In an in vivo test, the area under concentration-time curve and Cmax of LCDP-scCO2 formulation was 9.23 and 23.78 fold greater than LCDP-silica physical mixture (1:15, w/w), respectively, whereas the corresponding values were 1.92 and 2.80 fold greater than Lacipil®, respectively. Our results showed that the solid dispersion prepared by supercritical fluids technology is a feasible method to enhance the oral bioavailability of LCDP.

Quantitation of buried contamination by use of solvents. Part 1: Solvent degradation of amine cured epoxy resins

NASA Technical Reports Server (NTRS)

Rheineck, A. E.; Heskin, R. A.; Hill, L. W.

1972-01-01

The solubility and/or swelling of cured epoxy resins was studied using the solubility parameter method. Determination of solubility parameters were found in order to select solvents for solvent-assisted degradation of cured epoxy polymers used in spacecraft. A method for improving recovery of seeded spores is suggested for assay of buried contaminants. Three commercial epoxy resins were cured using four different alkyl amines. For each resin-amine combination, three levels of amine were used, corresponding to 1/3, 2/3, and all of the amine required to react with the oxirane groups of the resin. The solubility parameters of the 36 resulting model compounds were determined in poorly and moderately hydrogen-bonded solvents. No strongly hydrogen-bonded solvents caused dissolution or swelling. The tolerance of cured resins is discussed in terms of polymer structure.

Effect of solvent on in vitro dissolution: Summary of results for uranium, americium, and cobalt aerosols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guilmette, R.A.; Hoover, M.D.

1995-12-01

The revised 10 CFR Part 20 has adopted the ICRP Publication 30 method for calculating the committed effective dose equivalent from intakes of radionuclides. This dosimetry scheme requires knowledge or assumptions about the chemical form of the radionuclide, its particle size, and its known or assumed solubility. The solubility is classified as being either D (relatively soluble), W, or Y (relatively insoluble), depending on whether the material dissolves over periods of days, weeks, or years. Although Nuclear Regulatory Commission licensees may wish to take advantage of material-specific knowledge in order to adjust annual limits on intake and derived air concentrations,more » relatively few radioactive materials to which workers and the general population may be exposed have been adequately characterized either in terms of physicochemical form or solubility. Experimental measurement of solubility using some type of in vitro dissolution measurement system is therefore needed. However, there is currently no clear consensus regarding the appropriate design of in vitro dissolution systems, particularly when considering the range of different radionuclides to be studied, and the complexity of the biological mechanisms involved in the retention and clearance of inhaled deposited radioactive particles. The purpose of this study was to evaluate the effect of the several solvents on the dissolution of four test aerosols ({sup 57}Co{sub 3}O{sub 4}, {sup 241}AmO{sub 2}, ammonium diuranate [ADU], and U{sub 3}O{sub 8}) selected to encompass a variety of chemical and biochemical properties in vivo. The results of this study provide some guidance on the usefulness of in vitro dissolution tests for estimating the solubility of unknown radionuclide particles within the context of a simple model such as the class D, W, and Y formulation of ICRP 30.« less

Use of the co-grinding method to enhance the dissolution behavior of a poorly water-soluble drug: generation of solvent-free drug-polymer solid dispersions.

PubMed

Yang, Caiqin; Xu, Xiujuan; Wang, Jing; An, Zhiqian

2012-01-01

The solid dispersion (SD) technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs. In the present work, SDs of the Ca2+ channel blocker dipfluzine (DF) with polyvinylpyrrolidone K30 (PVP) and poloxamer 188 (PLXM) were prepared by the powder solid co-grinding method under a solvent-free condition. The properties of all SDs and physical mixtures were investigated by X-ray diffraction, Fourier-transform infrared, differential scanning calorimetry, scanning electron microscopy, dissolution test, and particles size determination. Eutectic compounds were produced between the DF and PLXM matrix during the co-grinding process, whereas glass suspension formed in the SDs with PVP carrier. Hydrogen bond formation was not observed between DF and carriers and DF was microcrystalline state in the PVP and PLXM matrices. The solubility of DF in different concentration of carriers at 25, 31, and 37°C was investigated; the values obtained were used to calculate the thermodynamic parameters of interaction between DF and carriers. The Gibbs free energy (ΔrGθ) values were negative, indicating the spontaneous nature of dispersing DF into the carriers. Moreover, entropy is the drive force when DF disperses into the matrix of PVP, while, enthalpy-driven dispersing encounters in the PLXM carrier. All the SDs of DF/carriers showed a considerably higher dissolution rate than pure DF and the corresponding physical mixtures. The cumulative dissolution rate at 10 min of the SD with a 1 : 3 DF/carrier ratio increased 5.1-fold for PVP and 5.5-fold for PLXM.

Two-Stage Separation of V(IV) and Al(III) by Crystallization and Solvent Extraction from Aluminum-Rich Sulfuric Acid Leaching Solution of Stone Coal

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing; Liu, Hong

2017-10-01

To improve separation of V(IV) and Al(III) from aluminum-rich sulfuric acid leaching solution of stone coal, the two-stage separation by crystallization and solvent extraction methods have been developed. A co-extraction coefficient ( k) was put forward to evaluate comprehensively co-extraction extent in different solutions. In the crystallization stage, 68.2% of aluminum can be removed from the solution. In the solvent extraction stage, vanadium was selectively extracted using di-2-ethylhexyl phosphoric acid/tri-n-butyl phosphate from the crystalline mother solution, followed by H2SO4 stripped efficiently. A V2O5 product with purity of 98.39% and only 0.10% Al was obtained after oxidation, precipitation, and calcination. Compared with vanadium extraction from solution without crystallization, the counter-current extraction stage of vanadium can be decreased from 6 to 3 and co-extraction coefficient ( k) decreased from 2.51 to 0.58 with two-stage separation. It is suggested that the aluminum removal by crystallization can evidently weaken the influence of aluminum co-extraction on vanadium extraction and improve the selectivity of solvent extraction for vanadium.

Part 1. The effect of microwave receptors on the liquefaction of Turkish coals by microwave energy in a hydrogen donor solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emine Yagmur; Taner Togrul

2005-12-01

The effects of microwave receptors to coal (receptor/coal) ratio and the period of heating by microwave energy on the solubilization of Turkish coals (Tuncbilek, Mugla-Yatagan, Beypazari lignites, and Zonguldak bituminous coal) in tetralin have been investigated. V{sub 2}O{sub 5} and TiO{sub 2} were used as microwave receptors. The changes of liquid product yield indicated that it depended significantly on the type and amount of receptor and the type of coal. A significant increase in the lignite conversions to oil fractions was observed by the addition of the V{sub 2}O{sub 5} receptor. The use of TiO{sub 2} receptor decreased the yieldmore » of THF soluble coal products. However, both V{sub 2}O{sub 5} and TiO{sub 2} receptors decreased the yield of preasphaltene (PAS) and asphaltene (AS) due to their catalytic effect on the coal liquefaction. 15 refs., 9 figs., 1 tab.« less

Improved solubility of DNA in recyclable and reusable bio-based deep eutectic solvents with long-term structural and chemical stability.

PubMed

Mondal, Dibyendu; Sharma, Mukesh; Mukesh, Chandrakant; Gupta, Vishal; Prasad, Kamalesh

2013-10-25

The solubility of DNA in bio-based deep eutectic solvents (DESs) consisting of mixtures of choline chloride with levulinic acid, glycerol, ethylene glycol, sorbitol and resorcinol was investigated. The macromolecule was found to be soluble and chemically and structurally stable in DESs consisting of mixtures containing glycerol and ethylene glycol. Furthermore recyclability of the DESs was demonstrated over three consecutive reuses in DNA dissolution.

Exploration of crystal simulation potential by fluconazole isomorphism and its application in improvement of pharmaceutical properties

NASA Astrophysics Data System (ADS)

Thakur, Amitha; Kumar, Dinesh; Thipparaboina, Rajesh; Shastri, Nalini R.

2014-11-01

Control of crystal morphology during crystallization is a paramount challenge in pharmaceutical processing. Hence, there is need to introduce computational methods for morphology prediction to manage production cost of drugs and improve related pharmaceutical and biopharmaceutical properties. Layer docking approach with molecular dynamics opens a new avenue for crystal habit prediction in presence of solvent. In the present study, attempts were made to correlate predicted and experimental crystal habits of fluconazole considering solvent interactions using layer docking approach. Simulated results from layer docking approach with methanol as solvent gave two dominant facets (0 1 1) and (1 0 1) with a surface area 22.43% and 19.82% respectively, which were in agreement with the experimental results. Experimentally grown modified crystal habit of fluconazole in methanol showed enhanced dissolution rate (p<0.05) when compared to plain drug. This was attributed to the increased surface area on the specified facets caused by interactions with the solvent. Furthermore, Differential Scanning Calorimetry, Fourier Transform Infrared (FTIR) Spectroscopy and powder X-ray Diffraction of recrystallized samples confirmed only a habit change and absence of any polymorphs, hydrates or solvates. Flow and compressibility of fluconazole recrystallized in methanol was significantly improved when compared to plain drug. This study demonstrates a methodical approach using computational tools for prediction and modification of crystal habit, to enhance dissolution of poorly soluble drugs, for future pharmaceutical applications.

Evaluation of cell wall damage by dimethyl sulfoxide in Candida species.

PubMed

León-García, María Cristina; Ríos-Castro, Emmanuel; López-Romero, Everardo; Cuéllar-Cruz, Mayra

2017-10-01

Studies dealing with the response of microorganisms to oxidative stress require the dissolution of oxidant agents in an appropriate solvent. A commonly used medium is dimethyl sulfoxide, which has been considered as an innocuous polar solvent. However, we have observed significant differences between control, untreated cells and those receiving increasing amounts of the oxidant and hence increasing amounts of DMSO, to the maximum allowed of 1%. Here we show that, while this solvent does not influence yeast cell viability, it does affect expression of cell wall proteins as well as catalase activity. Therefore, its use in future studies of oxidative stress as an innocuous solvent should be reconsidered. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Effects of mining activities on evolution of water chemistry in coal-bearing aquifers in karst region of Midwestern Guizhou, China: evidences from δ13C of dissolved inorganic carbon and δ34S of sulfate.

PubMed

Li, Qingguang; Wu, Pan; Zha, Xuefang; Li, Xuexian; Wu, Linna; Gu, Shangyi

2018-04-24

The generation of acid mine drainage (AMD) may accelerate watershed erosion and promote the migration of heavy metals, then threaten local ecosystems such as aquatic life and even human health. Previous studies have focused primarily on influence of AMD in surface environment. In order to reveal the acidizing processes in karst high-sulfur coalfield in Southwest China, this study, by contrast, focused on the hydrogeochemical evolution process and acidification mechanism of mine water in Zhijin coalfield, western Guizhou Province. The oxidation of pyrite and other sulfides induced strong acidification of mine water according to the water chemical analysis. As a result, a series of geochemical processes such as dissolution of carbonates and silicates, hydrolysis of metal ions, and degassing of CO 2 complicated water chemical evolution. The dissolution of silicates controlled the chemical composition of mine water, but more carbonates might be dissolved during the acidification of mine water. The sources of sulfate are quite different in water samples collected from the two selected mine. According to sulfur isotope analysis, the dissolution of gypsum is the primary source of sulfate in samples from Hongfa mine, whereas sulfide oxidation contributed a large amount of sulfate to the mine water in Fenghuangshan mine. The dissolution of carbonates should be an important source of DIC in mine water and CO 2 originating from organic mineralization might also have a certain contribution. This study elucidated the groundwater chemical evolution processes in high-sulfur coal-bearing strata and provided a foundation for further study of carbonates erosion and carbon emission during acidification of mine water.

Microfluidic production of single micrometer-sized hydrogel beads utilizing droplet dissolution in a polar solvent

PubMed Central

Sugaya, Sari; Yamada, Masumi; Hori, Ayaka; Seki, Minoru

2013-01-01

In this study, a microfluidic process is proposed for preparing monodisperse micrometer-sized hydrogel beads. This process utilizes non-equilibrium aqueous droplets formed in a polar organic solvent. The water-in-oil droplets of the hydrogel precursor rapidly shrunk owing to the dissolution of water molecules into the continuous phase. The shrunken and condensed droplets were then gelled, resulting in the formation of hydrogel microbeads with sizes significantly smaller than the initial droplet size. This study employed methyl acetate as the polar organic solvent, which can dissolve water at 8%. Two types of monodisperse hydrogel beads—Ca-alginate and chitosan—with sizes of 6–10 μm (coefficient of variation < 6%) were successfully produced. In addition, we obtained hydrogel beads with non-spherical morphologies by controlling the degree of droplet shrinkage at the time of gelation and by adjusting the concentration of the gelation agent. Furthermore, the encapsulation and concentration of DNA molecules within the hydrogel beads were demonstrated. The process presented in this study has great potential to produce small and highly concentrated hydrogel beads that are difficult to obtain by using conventional microfluidic processes. PMID:24396529

Microfluidic production of single micrometer-sized hydrogel beads utilizing droplet dissolution in a polar solvent.

PubMed

Sugaya, Sari; Yamada, Masumi; Hori, Ayaka; Seki, Minoru

2013-01-01

In this study, a microfluidic process is proposed for preparing monodisperse micrometer-sized hydrogel beads. This process utilizes non-equilibrium aqueous droplets formed in a polar organic solvent. The water-in-oil droplets of the hydrogel precursor rapidly shrunk owing to the dissolution of water molecules into the continuous phase. The shrunken and condensed droplets were then gelled, resulting in the formation of hydrogel microbeads with sizes significantly smaller than the initial droplet size. This study employed methyl acetate as the polar organic solvent, which can dissolve water at 8%. Two types of monodisperse hydrogel beads-Ca-alginate and chitosan-with sizes of 6-10 μm (coefficient of variation < 6%) were successfully produced. In addition, we obtained hydrogel beads with non-spherical morphologies by controlling the degree of droplet shrinkage at the time of gelation and by adjusting the concentration of the gelation agent. Furthermore, the encapsulation and concentration of DNA molecules within the hydrogel beads were demonstrated. The process presented in this study has great potential to produce small and highly concentrated hydrogel beads that are difficult to obtain by using conventional microfluidic processes.

[Preparation of ibuprofen/EC-PVP sustained-release composite particles by supercritical CO2 anti-solvent technology].

PubMed

Cai, Jin-Yuan; Huang, De-Chun; Wang, Zhi-Xiang; Dang, Bei-Lei; Wang, Qiu-Ling; Su, Xin-Guang

2012-06-01

Ibuprofen/ethyl-cellulose (EC)-polyvinylpyrrolidone (PVP) sustained-release composite particles were prepared by using supercritical CO2 anti-solvent technology. With drug loading as the main evaluation index, orthogonal experimental design was used to optimize the preparation process of EC-PVP/ibuprofen composite particles. The experiments such as encapsulation efficiency, particle size distribution, electron microscope analysis, infrared spectrum (IR), differential scanning calorimetry (DSC) and in vitro dissolution were used to analyze the optimal process combination. The orthogonal experimental optimization process conditions were set as follows: crystallization temperature 40 degrees C, crystallization pressure 12 MPa, PVP concentration 4 mgmL(-1), and CO2 velocity 3.5 Lmin(-1). Under the optimal conditions, the drug loading and encapsulation efficiency of ibuprofen/EC-PVP composite particles were 12.14% and 52.21%, and the average particle size of the particles was 27.621 microm. IR and DSC analysis showed that PVP might complex with EC. The experiments of in vitro dissolution showed that ibuprofen/EC-PVP composite particles had good sustained-release effect. Experiment results showed that, ibuprofen/EC-PVP sustained-release composite particles can be prepared by supercritical CO2 anti-solvent technology.

Successful topical dissolution of cholesterol gallbladder stones using ethyl propionate.

PubMed

Hofmann, A F; Amelsberg, A; Esch, O; Schteingart, C D; Lyche, K; Jinich, H; Vansonnenberg, E; D'Agostino, H B

1997-06-01

Topical dissolution of cholesterol gallbladder stones using methyl tert-butyl ether (MTBE) is useful in symptomatic patients judged too ill for surgery. Previous studies showed that ethyl propionate (EP), a C5 ester, dissolves cholesterol gallstones rapidly in vitro, but differs from MTBE in being eliminated so rapidly by the liver that blood levels remain undetectable. Our aim was to test EP as a topical dissolution agent for cholesterol gallbladder stones. Five high-risk patients underwent topical dissolution of gallbladder stones by EP. In three patients, the solvent was instilled via a cholecystostomy tube placed previously to treat acute cholecystitis; in two patients, a percutaneous transhepatic catheter was placed in the gallbladder electively. Gallstone dissolution was assessed by chromatography, by gravimetry, and by catheter cholecystography. Total dissolution of gallstones was obtained in four patients after 6-10 hr of lavage; in the fifth patient, partial gallstone dissolution facilitated basketing of the stones. In two patients, cholesterol dissolution was measured and averaged 30 mg/min. Side effects were limited to one episode of transient hypotension and pain at the infusion site; no patient developed somnolence or nausea. Gallstone elimination was associated with relief of symptoms. EP is an acceptable alternative to MTBE for topical dissolution of cholesterol gallbladder stones in high-risk patients. The lower volatility and rapid hepatic extraction of EP suggest that it may be preferable to MTBE in this investigational procedure.

Mass Transport Phenomena Between Bubbles and Dissolved Gases in Liquids Under Reduced Gravity Conditions

NASA Technical Reports Server (NTRS)

Dewitt, K. J.; Brockwell, J. L.

1985-01-01

The long term objective of the experiment is to observe the dissolution of isolated, immobile gas bubbles of specified size and composition in a solvent liquid of known concentration in the reduced gravity environment of earth orbit. Preliminary bubble dissolution experiment conducted both in the NASA Lewis 2.2 sec drop tower and in normal gravity using SO2 - Toluene system were not completely successful in their objective. The method of gas injection and lack of bubble interface stabiliy experienced due to the extreme solubility of SO in Toluene has the effects of changing the problem from that of bubble dissolution to one of bubble formation stability and subsequent dissolution in a liquid of unknown initial solute concentration. Current work involves further experimentation in order to refine the bubble injection system and to investigate the concept of having a bubble with a critical radius in a state of unstable equilibrium.

Proceedings: Fourteenth annual EPRI conference on fuel science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-05-01

EPRI's Fourteenth Annual Contractors' Conference on Fuel Science was held on May 18--19, 1989 in Palo Alto, CA. The conference featured results of work on coal science, coal liquefaction, methanol production, and coal oil coprocessing and coal upgrading. The following topics were discussed: recent development in coal liquefaction at the Wilsonville Clean Coal Research Center; British coal's liquid solvent extraction (LSE) process; feedstock reactivity in coal/oil co-processing; utility applications for coal-oil coprocessed fuels; effect of coal rank and quality on two-stage liquefaction; organic sulfur compounds in coals; the perchloroethylene refining process of high-sulfur coals; extraction of sulfur coals; extraction ofmore » sulfur from coal; agglomeration of bituminous and subbituminous coals; solubilization of coals by cell-free extracts derived from polyporus versicolor; remediation technologies and services; preliminary results from proof-of-concept testing of heavy liquid cyclone cleaning technology; clean-up of soil contaminated with tarry/oily organics; midwest ore processing company's coal benefication technology: recent prep plant, scale and laboratory activities; combustion characterization of coal-oil agglomerate fuels; status report on the liquid phase methanol project; biomimetic catalysis; hydroxylation of C{sub 2} {minus} C{sub 3} and cycloc{sub 6} hydrocarbons with Fe cluster catalysts as models for methane monooxygenase enzyme; methanol production scenarios; and modeling studies of the BNL low temperature methanol catalyst. Individual projects are processed separately for the data bases.« less

The effectiveness of eucalyptus oil, orange oil, and xylene in dissolving different endodontic sealers.

PubMed

Yadav, Hemant Kumar; Yadav, Rakesh Kumar; Chandra, Anil; Thakkar, Rahul Rameshbhai

2016-01-01

The objective of this study was to evaluate the dissolution effectiveness of eucalyptus oil, orange oil, xylene, and distilled water on three different endodontic sealers. About 240 samples of root canal sealers (eighty for each sealer) were prepared and divided into four groups of 20 each for immersion in different organic solvents. Each group was further subdivided into two subgroups (n = 10) for 2 and 10 min of immersion time. The mean percentage of weight loss was determined for each sealer in each solvent at both time periods. Data were statistically analyzed by two factor analysis of variance and significance of mean difference was obtained by Tukey's post hoc test (P < 0.05). The lowest level of solubility was observed for Adseal followed by Apexit Plus and Endomethasone N at both time periods in all solvents. Apexit Plus showed no significant (P > 0.05) difference in its dissolution in all the organic solvents except distilled water at both the time periods. The solubility profile of Endomethasone N and Adseal did not differ significantly among eucalyptus oil, orange oil, and xylene at 2 min and between eucalyptus oil and orange oil at 10 min. However, at 10 min, Endomethasone N and Adseal showed a more pronounced solubility in xylene as compared to both eucalyptus oil and orange oil. In general, xylene was the most effective in dissolving root canal sealers than other organic solvents. Essential oils (eucalyptus oil and orange oil) were found similar in their ability to dissolve Apexit Plus and Endomethasone N.

CO 2 Binding Organic Liquids Gas Capture with Polarity Swing Assisted Regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heldebrant, David

This report outlines the comprehensive bench-scale testing of the CO 2-binding organic liquids (CO 2BOLs) solvent platform and its unique Polarity Swing Assisted Regeneration (PSAR). This study outlines all efforts on a candidate CO 2BOL solvent molecule, including solvent synthesis, material characterization, preliminary toxicology studies, and measurement of all physical, thermodynamic and kinetic data, including bench-scale testing. Equilibrium and kinetic models and analysis were made using Aspen Plus™. Preliminary process configurations, a technoeconomic assessment and solvent performance projections for separating CO 2 from a subcritical coal-fired power plant are compared to the U.S. Department of Energy's Case 10 monoethanolamine baseline.

The separation of lanthanides and actinides in supercritical fluid carbon dioxide

DOE PAGES

Mincher, Bruce J.; Wai, Chien M.; Fox, Robert V.; ...

2015-10-28

Supercritical fluid carbon dioxide presents an attractive alternative to conventional solvents for recovery of the actinides and lanthanides. Carbon dioxide is a good solvent for fluorine and phosphate-containing ligands, including the traditional tributylphosphate ligand used in process-scale uranium separations. Actinide and lanthanide oxides may even be directly dissolved in carbon dioxide containing the complexes formed between these ligands and mineral acids, obviating the need for large volumes of acids for leaching and dissolution, and the corresponding organic liquid–liquid solvent extraction solutions. As a result, examples of the application of this novel technology for actinide and lanthanide separations are presented.

METHOD FOR DISSOLVING ZIRCONIUM-URANIUM COMPOSITIONS

DOEpatents

Gens, T.A.

1961-07-18

A method is descrioed for treating a zirconium-- uranium composition to form a stable solution from which uranium and other values may be extracted by contacting the composition with at least a 4 molar aqueous solution of ammonium fluoride at a temperature of about 100 deg C, adding a peroxide, in incremental amounts, to the heated solution throughout the period of dissolution until all of the uranium is converted to soluble uranyl salt, adding nitric acid to the resultant solution to form a solvent extraction feed solution to convert the uranyl salt to a solvent extractable state, and thereafter recovering the uranium and other desired values from the feed solution by solvent extraction.

Separation of nitrogen heterocyclic compounds from model coal tar fraction by solvent extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, S.J.; Chun, Y.J.

2005-07-01

The separation of four kinds of nitrogen heterocyclic compounds (NHCs) from a model mixture comprising NHCs (indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)), three kinds of bicyclic aromatic compounds (BACs; 1-methyl-naphthalene (IMN), 2-methyl naphthalene (2MN), dimethylnaphthalene (DMN)), biphenyl (Bp) and phenyl ether (Pe) was examined by a solvent extraction. The model mixture used as a raw material of this work was prepared according to the components and compositions contained in coal tar fraction (the temperature ranges of fraction: 240-265{sup o}C). An aqueous solution of methanol, ethanol, iso-propyl alcohol, N,N-dimethyl acetamide, DMF, formamide, N-methylformamide/methanol, and formamide/methanol were used as solvents.more » An aqueous solution of formamide was found suitable for separating NHCs contained in coal tar fraction based on distribution coefficient and selectivity. The effect of operation factors on separating NHCs was investigated by the distribution equilibrium using an aqueous solution of formamide. Increasing the operation temperature and the volume ratio of solvent to feed at initial (S/F)(o) resulted in improving the distribution coefficients of each NHC, but increasing the volume fraction of water in the solvent at initial (y(w,O)) resulted in deteriorating the distribution coefficients of each NHC. With increasing y(w,O) and (S/F)(o), the selectivities of each NHC in reference to DMN increased. Increase in operation temperature resulted in decrease in selectivities of each NHC in reference to DMN. At an experimental condition fixed, the sequence of the distribution coefficient and selectivity in reference to DMN for each NHC was In {gt} iQ {gt} Q {gt} Qu, and also the sequence of the distribution coefficient for each BAC was IMN {gt} 2MN {gt} DMN. The sequence of the distribution coefficient for entire compounds analyzed by this work was In {gt} iQ {gt} Q {gt} Qu {gt} BP {gt} 1MN {gt} 2MN {gt} Pe {gt} DMN.« less

Ionic solutions of two-dimensional materials

NASA Astrophysics Data System (ADS)

Cullen, Patrick L.; Cox, Kathleen M.; Bin Subhan, Mohammed K.; Picco, Loren; Payton, Oliver D.; Buckley, David J.; Miller, Thomas S.; Hodge, Stephen A.; Skipper, Neal T.; Tileli, Vasiliki; Howard, Christopher A.

2017-03-01

Strategies for forming liquid dispersions of nanomaterials typically focus on retarding reaggregation, for example via surface modification, as opposed to promoting the thermodynamically driven dissolution common for molecule-sized species. Here we demonstrate the true dissolution of a wide range of important 2D nanomaterials by forming layered material salts that spontaneously dissolve in polar solvents yielding ionic solutions. The benign dissolution advantageously maintains the morphology of the starting material, is stable against reaggregation and can achieve solutions containing exclusively individualized monolayers. Importantly, the charge on the anionic nanosheet solutes is reversible, enables targeted deposition over large areas via electroplating and can initiate novel self-assembly upon drying. Our findings thus reveal a unique solution-like behaviour for 2D materials that enables their scalable production and controlled manipulation.

Determination of the mode of occurrence of As, Cr, and Hg in three Chinese coal samples by sequential acid leaching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, B.; Li, W.; Wang, G.

2007-07-01

Sequential acid leaching was used to leach minerals and the trace elements they contain. One-step leaching uses concentrated nitric acid as solvent, while three-step leaching uses 5M hydrochloric acid, concentrated hydrofluoric acid, and concentrated hydrochloric acid as solvents. The sequential acid leaching by three-and one-step leach was also examined. The results showed that one-step leaching could leach over 80% of arsenic from coal samples, and also could leach mercury to a certain degree. During one-step leaching, little chromium is removed, but it is available to leach by three-step leaching; and during the sequential acid leaching by three and one-step leaching,more » almost 98% ash is leached. The result of acid leaching could also give detailed information on mode of occurrence of As, Cr, and Hg, which could be classified into: silicate association, pyrite association, organic association, and carbonates and sulfates association. Over half of chromium in the three coals is associated with organic matters and the rest is associated with silicates. The mode of occurrence of arsenic and mercury is mainly associated with different mineral matters depending on the coal samples studied.« less

Gas processing handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-04-01

Brief details are given of processes including: BGC-Lurgi slagging gasification, COGAS, Exxon catalytic coal gasification, FW-Stoic 2-stage, GI two stage, HYGAS, Koppers-Totzek, Lurgi pressure gasification, Saarberg-Otto, Shell, Texaco, U-Gas, W-D.IGI, Wellman-Galusha, Westinghouse, and Winkler coal gasification processes; the Rectisol process; the Catacarb and the Benfield processes for removing CO/SUB/2, H/SUB/2s and COS from gases produced by the partial oxidation of coal; the selectamine DD, Selexol solvent, and Sulfinol gas cleaning processes; the sulphur-tolerant shift (SSK) process; and the Super-meth process for the production of high-Btu gas from synthesis gas.

The use of mixed pyrrhotite/pyrite catalysts for co-liquefaction of coal and waste rubber tires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dadyburjor, D.B.; Zondlo, J.W.; Sharma, R.K.

1995-12-31

The overall objective of this research program is to determine the optimum processing conditions for tire/coal co-liquefaction. The catalysts used will be a ferric-sulfide-based materials, as well as promising catalysts from other consortium laboratories. The intent here is to achieve the maximum coal+tire conversion at the mildest conditions of temperature and pressure. Specific objectives include an investigation of the effects of time, temperature, pressure, catalyst and co-solvent on the conversion and product slate of the co-liquefaction. Accomplishments and conclusions are discussed.

Roles of molecular hydrogen and a hydrogen donor solvent in the cracking of moal model compounds with dispersed catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Toshimitsu; Ikenaga, Na-oki; Sakota, Takahiro

1994-12-31

It is of great importance to evaluate quantitative hydrogen transfer process by using coal model compounds with a hydrogen-donor solvent. Cronauer el al. showed that in the cracking of benzyl phenyl ether the hydrogen required to stabilize free radicals comes from a donor solvent or intramolecular rearrangement and not from gaseous hydrogen in the absence of a catalyst. Korobkov et al. and Schlosberg et al. showed that the thermolysis of benzyl phenyl ether and dibenzyl ether were accomplished by intramolecular rearrangements. Yokokawa et al. reported that tetralin retarded the catalyzed hydrocracking of coal model compounds containing C-C and C-O bonds.more » However, few studies dealt with quantitative discussion in the hydrogen transfer process from a hydrogen-donor solvent or molecular hydrogen to free radicals derived from a model compound except a series of studies by Nicole and co-workers. On the other hand, it is well known that the amount of naphthalene produced from tetralin decreases after the liquefaction of coal in tetralin with catalyst as compared to the liquefaction in the absence of catalysts. To account for this, two mechanisms are proposed. One is that the catalyst hydrogenates naphthalene produced from tetralin, and the other is that the catalyst promotes the direct hydrogen transfer from molecular hydrogen to free radicals. The purpose of this work is to elucidate the role of catalyst and tetralin by means of the quantitative treatment of the hydrogen transfer reaction stabilizing thermally decomposed free radicals. Cracking of benzyl phenyl ether (BPE), dibenzyl ether (DBE), 1,2-diphenylethane, and 1,3-diphenylpropane was studied in tetralin in the presence of highly disposed catalyst.« less

Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation

PubMed Central

Zhang, Anjie; Mu, Bin; Wang, Xiaowen; Wen, Lixin; Wang, Aiqin

2018-01-01

Different kinds of aluminosilicate minerals were employed to fabricate CoAl2O4 hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al2O3 and lightness of clay minerals. The higher the Al2O3 content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl2O4 nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl2O4 nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH)3 at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co2+/Al3+ for formation of spinel CoAl2O4 pigments in the process of high-temperature crystallization. PMID:29725589

Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation.

PubMed

Zhang, Anjie; Mu, Bin; Wang, Xiaowen; Wen, Lixin; Wang, Aiqin

2018-01-01

Different kinds of aluminosilicate minerals were employed to fabricate CoAl 2 O 4 hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al 2 O 3 and lightness of clay minerals. The higher the Al 2 O 3 content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl 2 O 4 nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl 2 O 4 nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH) 3 at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co 2+ /Al 3+ for formation of spinel CoAl 2 O 4 pigments in the process of high-temperature crystallization.

Explosive eruption of coal and basalt and the end-Permian mass extinction

PubMed Central

Ogden, Darcy E.; Sleep, Norman H.

2012-01-01

The end-Permian extinction decimated up to 95% of carbonate shell-bearing marine species and 80% of land animals. Isotopic excursions, dissolution of shallow marine carbonates, and the demise of carbonate shell-bearing organisms suggest global warming and ocean acidification. The temporal association of the extinction with the Siberia flood basalts at approximately 250 Ma is well known, and recent evidence suggests these flood basalts may have mobilized carbon in thick deposits of organic-rich sediments. Large isotopic excursions recorded in this period are potentially explained by rapid venting of coal-derived methane, which has primarily been attributed to metamorphism of coal by basaltic intrusion. However, recently discovered contemporaneous deposits of fly ash in northern Canada suggest large-scale combustion of coal as an additional mechanism for rapid release of carbon. This massive coal combustion may have resulted from explosive interaction with basalt sills of the Siberian Traps. Here we present physical analysis of explosive eruption of coal and basalt, demonstrating that it is a viable mechanism for global extinction. We describe and constrain the physics of this process including necessary magnitudes of basaltic intrusion, mixing and mobilization of coal and basalt, ascent to the surface, explosive combustion, and the atmospheric rise necessary for global distribution. PMID:22184229

Dissolution of pulp tissue by aqueous solution of chlorhexidine digluconate and chlorhexidine digluconate gel.

PubMed

Okino, L A; Siqueira, E L; Santos, M; Bombana, A C; Figueiredo, J A P

2004-01-01

To evaluate the activity of various root canal irrigants on bovine pulp tissue. The irrigants tested were: 0.5, 1.0 and 2.5% sodium hypochlorite; 2% aqueous solution of chlorhexidine digluconate; 2% chlorhexidine digluconate gel (Natrosol); and distilled water as control. Bovine pulp fragments were weighed and placed in contact with 20 mL of each tested substance in a centrifuge at 150 r.p.m. until total dissolution. Dissolution speed was calculated by dividing pulp weight by dissolution time. Statistical analysis was performed using the Kruskal-Wallis test. Distilled water and both solutions of chlorhexidine did not dissolve the pulp tissue within 6 h. Mean dissolution speeds for 0.5, 1.0 and 2.5% sodium hypochlorite solutions were 0.31, 0.43 and 0.55 mg min(-1), respectively. The solvent ability of chlorhexidine solutions was similar to that of distilled water. The results for sodium hypochlorite solutions, chlorhexidine solutions and distilled water were statistically different (P>0.01). Both chlorhexidine preparations and distilled water were not able to dissolve pulp tissue. All sodium hypochlorite solutions were efficient in dissolving pulp tissue; the dissolution speed varied with the concentration of the solution.

Improved Dissolution and Oral Bioavailability of Celecoxib by a Dry Elixir System.

PubMed

Cho, Kwan Hyung; Jee, Jun-Pil; Yang, Da A; Kim, Sung Tae; Kang, Dongjin; Kim, Dae-Young; Sim, Taeyong; Park, Sang Yeob; Kim, Kyeongsoon; Jang, Dong-Jin

2018-02-01

The purpose of this study was to develop and evaluate a dry elixir (DE) system for enhancing the dissolution rate and oral bioavailability of celecoxib. DE system has been used for improving solubility, oral bioavailability of poorly water-soluble drugs. The encapsulated drugs or solubilized drugs in the matrix are rapidly dissolved due to the co-solvent effect, resting in both an enhanced dissolution and bioavailability. DEs containing celecoxib were prepared by spray-drying method and characterized by morphology, drug/ethanol content, drug crystallinity, dissolution rate and oral bioavailability. The ethanol content and drug content in DE system could be easily altered by controlling the spraydrying conditions. The dissolution profile of celecoxib from DE proved to be much higher than that of celecoxib powder due to the nano-structured matrix, amorphous state and encapsulated ethanol. The bioavailability of celecoxib from DEs was compared with celecoxib powder alone and commercial product (Celebrex®) in rats. In particular, blood concentrations of celecoxib form DE formulation were much greater than those of native celecoxib and market product. The data demonstrate that the DE system could provide an useful solid dosage form to enhance the solubility, dissolution rate and oral bioavailability of celecoxib.

Process for coal liquefaction in staged dissolvers

DOEpatents

Roberts, George W.; Givens, Edwin N.; Skinner, Ronald W.

1983-01-01

There is described an improved liquefaction process by which coal is converted to a low ash and low sulfur carbonaceous material that can be used as a fuel in an environmentally acceptable manner without costly gas scrubbing equipment. In the process, coal is slurried with a pasting oil, passed through a preheater and at least two dissolvers in series in the presence of hydrogen-rich gases at elevated temperatures and pressures. Solids, including mineral ash and unconverted coal macerals, are separated from the condensed reactor effluent. In accordance with the improved process, the first dissolver is operated at a higher temperature than the second dissolver. This temperature sequence produces improved product selectivity and permits the incorporation of sufficient hydrogen in the solvent for adequate recycle operations.

Factors Affecting the Dissolution of Indomethacin Solid Dispersions.

PubMed

Zhang, Wei; Zhang, Chen-Ning; He, Yue; Duan, Ban-Yan; Yang, Guang-Yi; Ma, Wei-Dong; Zhang, Yong-Hong

2017-11-01

The aim of this study was to investigate the influence of factors such as carrier type, drug/carrier ratio, binary carriers, and preparation method on the dissolution of an insoluble drug, indomethacin (IM), under supersaturation conditions. Using a solvent evaporation (SE) method, poloxamer 188 and PVP K30 showed better dissolution among the selected carriers. Furthermore, as the ratio of carriers increased (drug/carrier ratio from 1:0.5 to 1:2), the dissolution rate increased especially in almost two times poloxamer 188 solid dispersions (SDs), while the reverse results were observed for PVP K30 SDs. For the binary carrier SD, a lower dissolution was found. Under hot melt extrusion (HME), the dissolution of poloxamer 188 SD and PVP K30 SD was 0.83- and 0.94-folds lower than that using SE, respectively, while the binary carrier SD showed the best dissolution. For poloxamer 188 SDs, the drug's crystal form changed when using SE, while no crystal form change was observed using HME. IM was amorphous in PVP K30 SDs prepared by both methods. For binary carrier systems, amorphous and crystalline drugs coexisted in SD using SE, and negligible amorphous IM was in SD using HME. This study indicated that a higher amorphous proportion in SD did not correlate with higher dissolution rate, and other factors, such as carrier type, particle size, and density, were also critical.

Effect of particle size on solubility, dissolution rate, and oral bioavailability: evaluation using coenzyme Q10 as naked nanocrystals

PubMed Central

Sun, Jiao; Wang, Fan; Sui, Yue; She, Zhennan; Zhai, Wenjun; Wang, Chunling; Deng, Yihui

2012-01-01

In this paper work, four naked nanocrystals (size range 80–700 nm) were prepared without any surfactant or polymer using the solvent/nonsolvent method. The effects of particle size on their solubility, dissolution, and oral bioavailability were investigated. Solubility and dissolution testing were performed in three types of dissolution medium, and the studies demonstrated that the equilibrium solubilities of coenzyme Q10 nanocrystals and bulk drugs were not affected by the dissolution media but the kinetic solubilities were. Kinetic solubility curves and changes in particle size distribution were determined and well explained by the proposed solubilization model for the nanocrystals and bulk drugs. The particle size effect on dissolution was clearly influenced by the diffusion coefficients of the various dissolution media, and the dissolution velocity of coenzyme Q10 increased as particle size decreased. The bioavailability of coenzyme Q10 after oral administration in beagle dogs was improved by reducing the particle size. For 700 nm nanocrystals, the AUC0–48 was 4.4-fold greater than that for the coarse suspensions, but a further decrease in particle size from 700 nm to 120 nm did not contribute to improvement in bioavailability until the particle size was reduced to 80 nm, when bioavailability was increased by 7.3-fold. PMID:23166438

Leaching kinetics of As, Mo, and Se from acidic coal fly ash samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neupane, Ghanashyam; Donahoe, Rona J.; Bhattacharyya, Siddhartha

Annually, coal-fired electric power plants produce large volumes potentially hazardous coal combustion products (CCPs) including fly ash. Since majority of the coal fly ash and other CCPs deposited in dry land fills or wet lagoons, they pose risk of contamination to local environment and hydrogeology. In this study, we present results of leaching kinetics for As, Mo, and Se from three acidic fly ash samples. This study shows that the leachate concentrations of As, Mo, and Se increase over time. Three kinetics equations, pseudo-second order, Elovich, and power-function, are able to adequately describe the experimental leaching kinetics data. Experimental leachingmore » data and modeling results indicate that the rate limiting leaching of As, Mo, and Se is largely controlled by the dissolution of the fly ash particles. Furthermore, it is important to adopt effective containment/treatment schemes to avoid potential and persistent dispersion of trace elements from ash disposal facilities to surrounding environment for a long time.« less

Leaching kinetics of As, Mo, and Se from acidic coal fly ash samples

DOE PAGES

Neupane, Ghanashyam; Donahoe, Rona J.; Bhattacharyya, Siddhartha; ...

2017-07-03

Annually, coal-fired electric power plants produce large volumes potentially hazardous coal combustion products (CCPs) including fly ash. Since majority of the coal fly ash and other CCPs deposited in dry land fills or wet lagoons, they pose risk of contamination to local environment and hydrogeology. In this study, we present results of leaching kinetics for As, Mo, and Se from three acidic fly ash samples. This study shows that the leachate concentrations of As, Mo, and Se increase over time. Three kinetics equations, pseudo-second order, Elovich, and power-function, are able to adequately describe the experimental leaching kinetics data. Experimental leachingmore » data and modeling results indicate that the rate limiting leaching of As, Mo, and Se is largely controlled by the dissolution of the fly ash particles. Furthermore, it is important to adopt effective containment/treatment schemes to avoid potential and persistent dispersion of trace elements from ash disposal facilities to surrounding environment for a long time.« less

Solubility Enhancement of Raloxifene Using Inclusion Complexes and Cogrinding Method

PubMed Central

Patil, Payal H.; Belgamwar, Veena S.; Patil, Pratibha R.; Surana, Sanjay J.

2013-01-01

The objective of the present work was to enhance the solubility and dissolution of practically water-insoluble drug raloxifene HCl (RLX), for the same two approaches that were used. In the first approach, drug was kneaded with hydroxypropyl-β-cyclodextrin (HPβCD), and in the second one drug was cogrinded with modified guar gum (MGG). The drug-cyclodextrin complex and drug-MGG cogrind mixtures were characterized by differential scanning calorimetry, X-ray diffraction studies, scanning electron microscopy, and Fourier transform infrared spectroscopy. The solubility and dissolution study reveals that solubility and dissolution rate of RLX remarkably increased in both methods. It was concluded that the prepared inclusion complex showed a remarkable increase in solubility and dissolution of poorly water-soluble drug raloxifene. In the cogrinding mixture, a natural modified gum is used as a surfactant and enhances the solubility and dissolution of RLX without requiring addition of organic solvent or high temperature for its preparation; thus, process is less cumbersome and cost effective. But when both methods were compared; HPβCD complexation method showed significant enhancement of drug solubility. PMID:26555984

Solid dispersions, part II: new strategies in manufacturing methods for dissolution rate enhancement of poorly water-soluble drugs.

PubMed

Bikiaris, Dimitrios N

2011-12-01

The absorption of poorly water-soluble drugs, when presented in the crystalline state to the gastrointestinal tract, is typically dissolution rate-limited, and according to BCS these drugs belong mainly to class II. Both dissolution kinetics and solubility are particle size dependent. Nowadays, various techniques are available to the pharmaceutical industry for dissolution rate enhancement of such drugs. Among such techniques, nanosuspensions and drug formulation in solid dispersions are those with the highest interest. This review discusses strategies undertaken over the last 10 years, which have been applied for the dissolution enhancement of poorly water-soluble drugs; such processes include melt mixing, electrospinning, microwave irradiation and the use of inorganic nanoparticles. Many problems in this field still need to be solved, mainly the use of toxic solvents, and for this reason the use of innovative new procedures and materials will increase over the coming years. Melt mixing remains extremely promising for the preparation of SDs and will probably become the most used method in the future for the preparation of solid drug dispersions.

Improving dissolution and oral bioavailability of pranlukast hemihydrate by particle surface modification with surfactants and homogenization

PubMed Central

Ha, Eun-Sol; Baek, In-hwan; Yoo, Jin-Wook; Jung, Yunjin; Kim, Min-Soo

2015-01-01

The present study was carried out to develop an oral formulation of pranlukast hemihydrate with improved dissolution and oral bioavailability using a surface-modified microparticle. Based on solubility measurements, surface-modified pranlukast hemihydrate microparticles were manufactured using the spray-drying method with hydroxypropylmethyl cellulose, sucrose laurate, and water and without the use of an organic solvent. The hydrophilicity of the surface-modified pranlukast hemihydrate microparticle increased, leading to enhanced dissolution and oral bioavailability of pranlukast hemihydrate without a change in crystallinity. The surface-modified microparticles with an hydroxypropylmethyl cellulose/sucrose laurate ratio of 1:2 showed rapid dissolution of up to 85% within 30 minutes in dissolution medium (pH 6.8) and oral bioavailability higher than that of the commercial product, with approximately 2.5-fold and 3.9-fold increases in area under the curve (AUC0→12 h) and peak plasma concentration, respectively. Therefore, the surface-modified microparticle is an effective oral drug delivery system for the poorly water-soluble therapeutic pranlukast hemihydrate. PMID:26150699

Preparation of theophylline-hydroxypropylmethylcellulose matrices using supercritical antisolvent precipitation: a preliminary study.

PubMed

Moneghini, M; Perissutti, B; Kikic, I; Grassi, M; Cortesi, A; Princivalle, F

2006-01-01

Several controlled release systems of drugs have been elaborated using a supercritical fluid process. Indeed, recent techniques using a supercritical fluid as a solvent or as an antisolvent are considered to be useful alternatives to produce fine powders. In this preliminary study, the effect of Supercritical Anti Solvent process (SAS) on the release of theophylline from matrices manufactured with hydroxypropylmethylcellulose (HPMC) was investigated. Two grades of HPMC (HPMC E5 and K100) as carriers were considered in order to prepare a sustained delivery system for theophylline which was used as a model drug. The characterization of the drug before and after SAS treatment, and the coprecipitates with carriers, was performed by X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The dissolution rate of theophylline, theophylline-coprecipitates, and matricial tablets prepared with coprecipitates were determined. The physical characterizations revealed a substantial correspondence of the drug solid state before and after supercritical fluid treatment while drug-polymer interactions in the SAS-coprecipitates were attested. The dissolution studies of the matrices prepared compressing the coprecipitated systems showed that the matrices based on HPMC K100 were able to promote a sustained release of the drug. Further, this advantageous dissolution performance was found to be substantially independent of the pH of the medium. The comparison with the matrices prepared with untreated substances demonstrated that matrices obtained with SAS technique can provide a slower theophylline release rate. A new mathematical model describing the in vitro dissolution kinetics was proposed and successfully tested on these systems.

Preparation, characterization and in vivo assessment of the bioavailability of glycyrrhizic acid microparticles by supercritical anti-solvent process.

PubMed

Sui, Xiaoyu; Wei, Wei; Yang, Lei; Zu, Yuangang; Zhao, Chunjian; Zhang, Lin; Yang, Fengjian; Zhang, Zhonghua

2012-02-28

In this study, glycyrrhizic acid (GA) microparticles were successfully prepared using a supercritical anti-solvent (SAS) process. Carbon dioxide and ethanol were used as the anti-solvent and solvent, respectively. The influences of several process parameters on the mean particle size (MPS), particle size distribution (PSD) and total yield were investigated. Processed particle sizes gradually decreased as temperature and solution flow rate increased. In addition, processed particle sizes increased from 119 to 205 nm as GA concentration increased. However, CO(2) flow rate did not significantly affect particle size. The optimized process conditions were applied, those included temperature (65 °C), pressure (250 bar), CO(2) and drug solution flow rate (15 and 8 mL min(-1)), drug concentration in ethanol (20 mg mL(-1)). Microparticles with a span of PSD ranging from 95 and 174 nm, MPS of 128 nm were obtained, and total yield was 63.5%. The X-ray diffraction patterns of glycyrrhizic acid microparticles show apparent amorphous nature. Fourier transform infrared (FT-IR) spectroscopy results show that no chemical structural changes occurred. The in vitro dissolution tests showed that the GA microparticles exhibited great enhancement of dissolution performance when compared to GA original drug. Furthermore, the in vivo studies revealed that the microparticles provided improved pharmacokinetic parameter after oral administration to rats as compared with original drug. Copyright © 2011 Elsevier B.V. All rights reserved.

Solubilization and spore recovery from silicone polymers. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Hsiao, Y. C.

1974-01-01

A non-sporicidal technique for solvent degradation of cured silicone polymers was developed which involves chemical degradation of cured silicone polymers by amine solvents at room temperature. Substantial improvements were obtained in the recovery of seeded spores from room temperature cured polymers as compared to the standard recovery procedures, which indicates that the curing process is not sufficiently exothermic to reduce spore viability. The dissolution reaction of cured silicone polymers whith amine solvents is proposed to occur by bimolecular nucleophilic displacement. The chemical structure of silicone polymers was determined by spectroscopic methods. The phenyl to methyl ratio, R/Si ratio, molecular weight, and hydroxyl content of the silicone resins were determined.

Comparative physicochemical properties of hydrocortisone-PVP composites prepared using supercritical carbon dioxide by the GAS anti-solvent recrystallization process, by coprecipitation and by spray drying.

PubMed

Corrigan, Owen I; Crean, Abina M

2002-10-01

Hydrocortisone-PVP composites were successfully prepared using the supercritical fluid gas anti-solvent method (GAS). Analysis by differential scanning calorimetry DSC and powder X-ray diffraction (XRD) indicated that these systems were more crystalline than corresponding systems prepared by spray drying. These systems, prepared by the GAS method were more similar in physicochemical properties to coprecipitates prepared by conventional solvent evaporation. Compressed composites of hydrocortisone-PVP systems, prepared by the GAS method, had dissolution rates lower than those of corresponding systems prepared by the other processing methods but equivalent to those of corresponding physical mixtures.

Selective dissolution of halide perovskites as a step towards recycling solar cells

PubMed Central

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

2016-01-01

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells. PMID:27211006

Selective dissolution of halide perovskites as a step towards recycling solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Here, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO 2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easilymore » decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb 2+ cations. After 10 cycles of recycling, a mesoporous TiO 2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.« less

Selective dissolution of halide perovskites as a step towards recycling solar cells

DOE PAGES

Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; ...

2016-05-23

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Here, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO 2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easilymore » decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb 2+ cations. After 10 cycles of recycling, a mesoporous TiO 2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.« less

Bench-Scale Development of a Non-Aqueous Solvent (NAS) CO2 Capture Process for Coal-Fired Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lail, Marty

The project aimed to advance RTI’s non-aqueous amine solvent technology by improving the solvent to reduce volatility, demonstrating long-term continuous operation at lab- (0.5 liters solvent) and bench-scale (~120 liters solvent), showing low reboiler heat duty measured during bench-scale testing, evaluating degradation products, building a rate-based process model, and evaluating the techno-economic performance of the process. The project team (RTI, SINTEF, Linde Engineering) and the technology performed well in each area of advancement. The modifications incorporated throughout the project enabled the attainment of target absorber and regenerator conditions for the process. Reboiler duties below 2,000 kJt/kg CO2 were observed inmore » a bench-scale test unit operated at RTI.« less

Processing and analysis techniques involving in-vessel material generation

DOEpatents

Schabron, John F [Laramie, WY; Rovani, Jr., Joseph F.

2011-01-25

In at least one embodiment, the inventive technology relates to in-vessel generation of a material from a solution of interest as part of a processing and/or analysis operation. Preferred embodiments of the in-vessel material generation (e.g., in-vessel solid material generation) include precipitation; in certain embodiments, analysis and/or processing of the solution of interest may include dissolution of the material, perhaps as part of a successive dissolution protocol using solvents of increasing ability to dissolve. Applications include, but are by no means limited to estimation of a coking onset and solution (e.g., oil) fractionating.

Processing and analysis techniques involving in-vessel material generation

DOEpatents

Schabron, John F [Laramie, WY; Rovani, Jr., Joseph F.

2012-09-25

In at least one embodiment, the inventive technology relates to in-vessel generation of a material from a solution of interest as part of a processing and/or analysis operation. Preferred embodiments of the in-vessel material generation (e.g., in-vessel solid material generation) include precipitation; in certain embodiments, analysis and/or processing of the solution of interest may include dissolution of the material, perhaps as part of a successive dissolution protocol using solvents of increasing ability to dissolve. Applications include, but are by no means limited to estimation of a coking onset and solution (e.g., oil) fractionating.

Hydrogen donor solvent coal liquefaction process

DOEpatents

Plumlee, Karl W.

1978-01-01

An indigenous hydrocarbon product stream boiling within a range of from about C.sub.1 -700.degree. F., preferably C.sub.1 -400.degree. F., is treated to produce an upgraded hydrocarbon fuel component and a component which can be recycled, with a suitable donor solvent, to a coal liquefaction zone to catalyze the reaction. In accordance therewith, a liquid hydrocarbon fraction with a high end boiling point range up to about 700.degree. F., preferably up to about 400.degree. F., is separated from a coal liquefaction zone effluent, the separated fraction is contacted with an alkaline medium to provide a hydrocarbon phase and an aqueous extract phase, the aqueous phase is neutralized, and contacted with a peroxygen compound to convert indigenous components of the aqueous phase of said hydrocarbon fraction into catalytic components, such that the aqueous stream is suitable for recycle to the coal liquefaction zone. Naturally occurring phenols and alkyl substituted phenols, found in the aqueous phase, are converted, by the addition of hydroxyl constituents to phenols, to dihydroxy benzenes which, as disclosed in copending Application Ser. Nos. 686,813 now U.S. Pat. No. 4,049,536; 686,814 now U.S. Pat. No. 4,049,537; 686,827 now U.S. Pat. No. 4,051,012 and 686,828, K. W. Plumlee et al, filed May 17, 1976, are suitable hydrogen transfer catalysts.

Effect of N-Methyl Substitution in the Glycine Molecule on the Enthalpy of Dissolution in Mixed Water-Alcohol Solvents at 298.15 K

NASA Astrophysics Data System (ADS)

Badelin, V. G.; Smirnov, V. I.

2018-07-01

The enthalpies of dissolution of N-methylglycine in water + ethanol, water + (1-propanol) and water + (2-propanol) are determined via calorimetry at an alcohol concentration of x 2 = 0-0.25 mole fraction. The standard values of enthalpies of dissolution (Δ_{sol}H°) and transfer (Δ_{tr}H°) of N-methylglycine from water to solution are calculated. The effect the structure and properties of N-methylglycine and the composition of a water-alcohol mixture have on N-methylglycine's enthalpy characteristics is examined. The enthalpy coefficients of pair interactions ( h xy ) between N-methylglycine and alcohol molecules are calculated. They have positive values and grow in the series ethanol (EtOH) < 1-propanol (1-PrOH), < 2-propanol (2-PrOH). A comparative analysis is performed of the enthalpy characteristics of dissolution and transfer of N-methylglycine and the analogous characteristics of glycine and DL-α-alanine in similar mixtures.

Formulation and Solid State Characterization of Nicotinamide-based Co-crystals of Fenofibrate

PubMed Central

Shewale, Sheetal; Shete, A. S.; Doijad, R. C.; Kadam, S. S.; Patil, V. A.; Yadav, A. V.

2015-01-01

The present investigation deals with formulation of nicotinamide-based co-crystals of fenofibrate by different methods and solid-state characterization of the prepared co-crystals. Fenofibrate and nicotinamide as a coformer in 1:1 molar ratio were used to formulate molecular complexes by kneading, solution crystallization, antisolvent addition and solvent drop grinding methods. The prepared molecular complexes were characterized by powder X-ray diffractometry, differential scanning calorimetry, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and in vitro dissolution study. Considerable improvement in the dissolution rate of fenofibrate from optimized co-crystal formulation was due to an increased solubility that is attributed to the super saturation from the fine co-crystals is faster because of large specific surface area of small particles and prevention of phase transformation to pure fenofibrate. In vitro dissolution study showed that the formation of co-crystals improves the dissolution rate of fenofibrate. Nicotinamide forms the co-crystals with fenofibrate, theoretically and practically. PMID:26180279

Effect of the composition of a solution on the enthalpies of solvation of piperidine in methanol-acetonitrile and dimethylsulfoxide-acetonitrile mixed solvents

NASA Astrophysics Data System (ADS)

Kuz'mina, I. A.; Volkova, M. A.; Sitnikova, K. A.; Sharnin, V. A.

2014-01-01

Heat effects of dissolution of piperidine (ppd) are measured by calorimetry at 298.15 K over the range of composition of acetonitrile-methanol (AN-MeOH) mixed solvents. Based on the Δsol H ○(ppd)AN-MeOH values obtained using the literature data on Δsol H ○ (ppd) in acetonitrile-dimethylsulfoxide (AN-DMSO) mixed solvents and the vaporization enthalpy of ppd, the enthalpies of solvation of amine in AN-MeOH and AN-DMSO binary mixtures are calculated. A rise in the exothermicity of solvation of piperidine is observed upon the transition from AN to DMSO and MeOH, due mainly to the enhanced solvation of the amino group of ppd as a result of changes in the acid-base properties of the mixed solvent.

Performance of a diesel engine operating on raw coal-diesel fuel and solvent refined coal-diesel fuel slurries. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, H.P.

1980-03-01

Performance tests using an 11 kW single cylinder diesel engine were made to determine the effects of three different micronized coal-fuel oil slurries being considered as alternative fuels. Slurries containing 20, 32, and 40%-wt micronized raw coal in No. 2 fuel oil were used. Results are presented indicating the changes in the concentrations of SO/sub X/ and NO/sub X/ in the exhaust, exhaust opacity, power and efficiency, and in wear rates relative to operation on fuel oil No. 2. The engine was operated for 10 h at full load and 1400 rpm on al fuels except the 40%-wt slurry. Thismore » test was discontinued because of extremely poor performance.« less

Performance of a diesel engine operating on raw coal-diesel fuel and solvent refined coal-diesel fuel slurries. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, H.P.

1980-03-01

Performance tests using an 11 kw single cylinder diesel engine were made to determine the effects of three different micronized coal-fuel oil slurries being considered as alternative fuels. Slurries containing 20, 32, and 40 percent by weight micronized raw coal in No. 2 fuel oil were used. Results are presented indicating the changes in the concentrations of SO/sub X/ and NO/sub X/ in the exhaust, exhaust opacity, power and efficiency, and in wear rates relative to operation on fuel oil No. 2. The engine was operated for 10 hrs at full load and 1400 rpm on all fuels except themore » 40% by weight slurry. This test was discontinued because of extremely poor performance.« less

Dissolution of di-2-ethylhexyl phosphates of ree in an octane + octanol mixture under the influence of gaseous ammonia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trifonov, Y.I.; Legin, E.K.; Suglobov, D.N.

1986-03-01

The authors find that the solubility of di-2-ethylhexyl phosphates rises considerably under the influence of gaseous ammonia on the solvent-LnA/sub 3/ system when a mixture of octane and octanol is used as solvent. The dissolving power of ammonia rises with alcohol concentration and attains the maximum at an alcohol content of ca 20 vol. %. An equation is presented that describes the dependence of the LnA/sub 3/ solubility on the partial amonia pressure.

Ionic Liquids Can Selectively Change the Conformational Free-Energy Landscape of Sugar Rings.

PubMed

Jarin, Zack; Pfaendtner, Jim

2014-02-11

We investigated the conformational free energy landscape of glucose solvated in water and in the ionic liquids (ILs) 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and 1-butyl-3-methylimidazoulim boron tetrafluoride ([Bmim][BF4]). To quantify equilibrium thermodynamic solvent effects, molecular dynamics simulations in conjunction with enhanced sampling based on the metadynamics framework were used. The results show that the solvent choice induces significant differences in the equilibrium ring structures, which may help further resolve the molecular mechanism governing IL-mediated cellulose dissolution.

Carbonated Science Cleans Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rousseau, Roger; Heldebrant, David; Glezakou, Vand

Similar to the properties of soda, liquid solvents can efficiently capture and convert carbon dioxide from coal power plants. Researchers at PNNL explain this process and how this method can turn captured carbon into plastic or fuel.

Low-energy collision induced dissociation (low-energy CID), collision induced dissociation (CID) and higher-energy collision dissociation (HCD) mass spectrometry for structural elucidation of saccharides and clarification of their dissolution mechanism in DMAc/LiCl.

PubMed

Bayat, Parisa; Lesage, Denis; Cole, Richard B

2018-05-29

The dissolution mechanism of oligosaccharides in N,N-dimethylacetamide/lithium chloride (DMAc/LiCl), a solvent used for cellulose dissolution, and the capabilities of low-energy collision induced dissociation (low-energy CID), collision induced dissociation (CID) and higher-energy collision dissociation (HCD) for structural analysis of carbohydrates were investigated. Comparing the spectra obtained using three techniques shows that, generally, when working with mono-lithiated sugars, CID spectra provide more structurally informative fragments, and glycosidic bond cleavage is the main pathway. However, when working with di-lithiated sugars, HCD spectra can be more informative providing predominately cross-ring cleavage fragments. This is because HCD is a non-resonant activation technique and it allows a higher amount of energy to be deposited in a short time, giving access to more endothermic decomposition pathways as well as consecutive fragmentations. The difference in preferred dissociation pathways of mono-lithiated and di-lithiated sugars indicates that the presence of the second lithium strongly influences the relative rate constants for cross-ring cleavages (rearrangement) vs. direct glycosidic bond cleavages, and disfavors the latter. Regarding the dissolution mechanism of sugars in DMAc/LiCl, CID and HCD experiments on di-lithiated and tri-lithiated sugars reveal that intensities of product ions containing two Li + or three Li + , respectively, are higher than those bearing only one Li + . In addition, comparing the fragmentation spectra (both HCD and CID) of LiCl adducted lithiated sugar and NaCl adducted sodiated sugar shows that while, in the latter case, loss of NaCl is dominant, in the former case, loss of HCl occurs preferentially. The compiled evidence implies that there is a strong and direct interaction between lithium and the saccharide during the dissolution process in the DMAc/LiCl solvent system. This article is protected by copyright. All rights reserved.

TEM study of PM2.5 emitted from coal and tire combustion in a thermal power station.

PubMed

Gieré, Reto; Blackford, Mark; Smith, Katherine

2006-10-15

The research presented here was conducted within the scope of an experiment investigating technical feasibility and environmental impacts of tire combustion in a coal-fired power station. Previous work has shown that combustion of a coal+tire blend rather than pure coal increased bulk emissions of various elements (e.g., Zn, As, Sb, Pb). The aim of this study is to characterize the chemical and structural properties of emitted single particles with dimensions <2.5 microm (PM2.5). This transmission electron microscope (TEM)-based study revealed that, in addition to phases typical of coal fly ash (e.g., aluminum-silicate glass, mullite), the emitted PM2.5 contains amorphous selenium particles and three types of crystalline metal sulfates never reported before from stack emissions. Anglesite, PbSO4, is ubiquitous in the PM2.5 derived from both fuels and contains nearly all Pb present in the PM. Gunningite, ZnSO4-H2O, is the main host for Zn and only occurs in the PM derived from the coal+tire blend, whereas yavapaiite, KFe3+(SO4)2, is present only when pure coal was combusted. We conclude that these metal sulfates precipitated from the flue gas, may be globally abundant aerosols, and have, through hydration or dissolution, a major environmental and health impact.

Slipstream pilot-scale demonstration of a novel amine-based post-combustion technology for carbon dioxide capture from coal-fired power plant flue gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnamurthy, Krish R.

Post-combustion CO 2 capture (PCC) technology offers flexibility to treat the flue gas from both existing and new coal-fired power plants and can be applied to treat all or a portion of the flue gas. Solvent-based technologies are today the leading option for PCC from commercial coal-fired power plants as they have been applied in large-scale in other applications. Linde and BASF have been working together to develop and further improve a PCC process incorporating BASF’s novel aqueous amine-based solvent technology. This technology offers significant benefits compared to other solvent-based processes as it aims to reduce the regeneration energy requirementsmore » using novel solvents that are very stable under the coal-fired power plant feed gas conditions. BASF has developed the desired solvent based on the evaluation of a large number of candidates. In addition, long-term small pilot-scale testing of the BASF solvent has been performed on a lignite-fired flue gas. In coordination with BASF, Linde has evaluated a number of options for capital cost reduction in large engineered systems for solvent-based PCC technology. This report provides a summary of the work performed and results from a project supported by the US DOE (DE-FE0007453) for the pilot-scale demonstration of a Linde-BASF PCC technology using coal-fired power plant flue gas at a 1-1.5 MWe scale in Wilsonville, AL at the National Carbon Capture Center (NCCC). Following a project kick-off meeting in November 2011 and the conclusion of pilot plant design and engineering in February 2013, mechanical completion of the pilot plant was achieved in July 2014, and final commissioning activities were completed to enable start-up of operations in January 2015. Parametric tests were performed from January to December 2015 to determine optimal test conditions and evaluate process performance over a variety of operation parameters. A long-duration 1500-hour continuous test campaign was performed from May to August 2016 at a selected process condition to evaluate process performance and solvent stability over a longer period similar to how the process would operate as a continuously running large-scale PCC plant. The pilot plant integrated a number of unique features of the Linde-BASF technology aimed at lowering overall energy consumption and capital costs. During the overall test period including startup, parametric testing and long-duration testing, the pilot plant was operated for a total of 6,764 hours out of which testing with flue gas was performed for 4,109 hours. The pilot plant testing demonstrated all of the performance targets including CO 2 capture rate exceeding 90%, CO 2 purity exceeding 99.9 mol% (dry), flue gas processing capacity up to 15,500 lbs/hr (equivalent to 1.5 MWe capacity slipstream), regeneration energy as low as 2.7 GJ/tonne CO 2, and regenerator operating pressure up to 3.4 bara. Excellent solvent stability performance data was measured and verified by Linde and BASF during both test campaigns. In addition to process data, significant operational learnings were gained from pilot tests that will contribute greatly to the commercial success of PCC. Based on a thorough techno-economic assessment (TEA) of the Linde-BASF PCC process integrated with a 550 MWe supercritical coal-fired power plant, the net efficiency of the integrated power plant with CO 2 capture is increased from 28.4% with the DOE/NETL Case 12 reference to 30.9% with the Linde-BASF PCC plant previously presented utilizing the BASF OASE® blue solvent [Ref. 4], and is further increased to 31.4% using a Linde-BASF PCC plant with BASF OASE® blue solvent and an advanced stripper interstage heater (SIH) configuration. The Linde-BASF PCC plant incorporating the BASF OASE® blue solvent also results in significantly lower overall capital costs, thereby reducing the cost of electricity (COE) and cost of CO 2 captured from $147.25/MWh and $56.49/MT CO 2, respectively, for the reference DOE/NETL Case 12 plant, to $128.49/MWh and $41.85/MT CO2 for process case LB1, respectively, and $126.65/MWh and $40.66/MT CO 2 for process case SIH, respectively. With additional innovative Linde-BASF PCC process configuration improvements, the COE and cost of CO 2 captured can be further reduced to $125.51/MWh and $39.90/MT CO 2 for a further optimized PCC process defined as LB1-CREB. Most notably, the Linde-BASF process options assessed have already demonstrated the potential to lower the cost of CO 2 captured below the DOE target of $40/MT CO 2 at the 550 MWe scale for second generation PCC technologies. Project organization, structure, goals, tasks, accomplishments, process criteria and milestones will be presented in this report along with highlights and key results from parametric and long-duration testing of the Linde-BASF PCC pilot. The parametric and long-duration testing campaigns were aimed at validating the performance of the PCC technology against targets determined from a preliminary techno-economic assessment. The stability of the solvent with extended operation in a realistic power plant setting was measured with performance verified. Additionally, general solvent classification information, process operating conditions, normalized solvent performance data, solvent stability test results, flue gas conditions data, CO 2 purity data in the gaseous product stream, steam requirements and process flow diagrams, and updated process economic data for a scaled-up 550 MWe supercritical power plant with CO 2 capture are presented and discussed in this report.« less

Fate of the naturally occurring radioactive materials during treatment of acid mine drainage with coal fly ash and aluminium hydroxide.

PubMed

Madzivire, Godfrey; Maleka, Peane P; Vadapalli, Viswanath R K; Gitari, Wilson M; Lindsay, Robert; Petrik, Leslie F

2014-01-15

Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stations generate huge amounts of coal fly ash of which a small amount is used in the construction industry. Mining exposes pyrite containing rocks to H2O and O2. This results in the oxidation of FeS2 to form H2SO4. The acidic water, often termed acid mine drainage (AMD), causes dissolution of potentially toxic elements such as, Fe, Al, Mn and naturally occurring radioactive materials such as U and Th from the associated bedrock. This results in an outflow of AMD with high concentrations of sulphate ions, Fe, Al, Mn and naturally occurring radioactive materials. Treatment of AMD with coal fly ash has shown that good quality water can be produced which is suitable for irrigation purposes. Most of the potentially toxic elements (Fe, Al, Mn, etc) and substantial amounts of sulphate ions are removed during treatment with coal fly ash. This research endeavours to establish the fate of the radioactive materials in mine water with coal fly ash containing radioactive materials. It was established that coal fly ash treatment method was capable of removing radioactive materials from mine water to within the target water quality range for drinking water standards. The alpha and beta radioactivity of the mine water was reduced by 88% and 75% respectively. The reduced radioactivity in the mine water was due to greater than 90% removal of U and Th radioactive materials from the mine water after treatment with coal fly ash as ThO2 and UO2. No radioisotopes were found to leach from the coal fly ash into the mine water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bench-Scale Silicone Process for Low-Cost CO{sub 2} Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vipperla, Ravikumar; Yee, Michael; Steele, Ray

This report presents system and economic analysis for a carbon capture unit which uses an amino-silicone solvent for CO{sub 2} capture and sequestration (CCS) in a pulverized coal (PC) boiler. The amino-silicone solvent is based on GAP-1 with Tri-Ethylene Glycol (TEG) as a co-solvent. The report also shows results for a CCS unit based on a conventional approach using mono-ethanol amine (MEA). Models were developed for both processes and used to calculate mass and energy balances. Capital costs and energy penalty were calculated for both systems, as well as the increase in cost of electricity. The amino-silicone solvent based systemmore » demonstrates significant advantages compared to the MEA system.« less

Bench-Scale Silicone Process for Low-Cost CO{sub 2} Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vipperla, Ravikumar; Yee, Michael; Steele, Ray

This report presents system and economic analysis for a carbon capture unit which uses an amino-silicone solvent for CO{sub 2} capture and sequestration (CCS) in a pulverized coal (PC) boiler. The amino-silicone solvent is based on GAP-1 with tri-ethylene glycol (TEG) as a co-solvent. For comparison purposes, the report also shows results for a CCS unit based on a conventional approach using mono-ethanol amine (MEA). At a steam temperature of 395 °C (743 °F), the CCS energy penalty for amino-silicone solvent is only 30.4% which compares to a 35.9% energy penalty for MEA. The increase in COE for the amino-siliconemore » solvent relative to the non-capture case is between 98% and 103% (depending on the solvent cost) which compares to an ~109% COE cost increase for MEA. In summary, the amino-silicone solvent has significant advantages over conventional systems using MEA.« less

DIRECT LIQUEFACTION PROOF OF CONCEPT

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The eighth bench scale test of POC program, Run PB-08, was successfully completed from August 8 to August 26, 1997. A total of five operating conditions were tested aiming at evaluating the reactivity of different pyrolysis oils in liquefaction of a Wyoming sub-bituminous coal (Black Thunder coal). For the first time, water soluble promoters were incorporated into the iron-based GelCat to improve the dispersion of the promoter metals in the feed blend. The concentration of the active metals, Mo and Fe, was 100 and 1000 ppm of moisture-free coal, respectively. Black Thunder coal used in this run was the samemore » batch as tested in HTI�s Run POC-02. Similar to Runs PB-01 through 7, this run employed two back mixed slurry reactors, an interstage gas/slurry separator and a direct-coupled hydrotreater. In addition to the hot vapor from the second stage separator, the first stage separator overhead liquid was also fed to the hydrotreater, which was packed with Criterion C-411 hydrotreating catalyst. Pyrolysis oil was produced off-line from a pyrolysis unit acquired from University of Wyoming. Solids rejection was achieved by purging out pressure filter solid. The recycle solvents consisted of O-6 separator bottoms and pressure filter liquid (PFL). The Run PB-08 proceeded very smoothly without any interruptions. Coal conversion consistently above 90W% was achieved. High resid conversion and distillate yield have been obtained from co-processing of coal and 343°C+ (650°F+) pyrolysis oil. Light gas (C 1-C 3 ) yield was minimized and hydrogen consumption was reduced due to the introduction of pyrolysis oil, compared with conventional coal-derived solvent. Catalytic activity was improved by incorporating a promoter metal into the iron-based GelCat. It seemed that lowering the first stage temperature to 435°C might increase the hydrogenation function of the promoter metal. In comparison with previous coal-waste coprocessing run (PB-06), significant improvements in the process performance were achieved due to catalyst modification and integration of pyrolysis technique into liquefaction.« less

[Studies on hydroxyapatite applicatied in coprecipitate of total salvianolic acids phospholipid complex].

PubMed

Chen, Xiao-Yun; Zhang, Zhen-Hai; Liu, Dan; Sun, E; Jia, Xiao-Bin

2014-03-01

The purpose of this research was to prepare total salvianolic acids-phytosome-HA coprecipitate to improve drug dissolution and its micromeritic properties. Firstly, the coprecipitate was prepared by solvent method and in vitro dissolution of tripterine was performed with the salvianolic acid B and danshensu as criteria. At the same time, the micromeritic properties was characterizated, the structure of samples was characterized by TEM, DSC, XRD and FTIR. Results showed that when the ratio of drug to HA was 1:2, it had a better dissolution, the accumulative drug-release percent in vitro at 60 min was over 90%. At the same time, it has good liquidity and low moisture absorption. Its micromeritic properties have improved. It is proved that the drug still existed amorphously by microstructure analysis. The preparation process is simple and feasible, it has practical value.

Chemistry and structure of coal-derived asphaltenes, Phase III. Quarterly progress report, January--March 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yen, T. F.

1978-01-01

The solubility limits of Synthoil and PAMCO asphaltenes have been measured as a function of Hildebrand solubility parameters and hydrogen bonding. Solvents with moderate hydrogen bonding capacity such as dioxane, ethyl benzoate and dibutyl phthalate were found to be most effective in dissolving asphaltenes over the widest range of solubility parameters. VPO molecular weight studies of coal liquid derived carbenes, as a function of concentration in the solvent THF, indicate that these fractions are more strongly self-associated than the corresponding asphaltenes, and generally afford high infinite dilution number average molecular weights: Synthoil, 861; HRI H-Coal, 1156; Cat. Inc. SRC, 1228;more » PAMCO SRC, 1054. The variable ESR temperature dependence of the spin intensity for a Synthoil asphaltene-I/sub 2/ charge transfer followed a 1/T (Curie--Weiss) dependence over the temperature range from 25/sup 0/ to -114/sup 0/C suggesting that independent, non-interacting donor and acceptor doublets were formed. Weight percent OH values, determined from 'H NMR analysis of silylated asphaltenes, were found to provide a reasonably linear correlation with the absorbance of the monomeric OH infrared stretching bands of the asphaltenes.« less

40 CFR 60.43Da - Standards for sulfur dioxide (SO2).

Code of Federal Regulations, 2014 CFR

2014-07-01

... into the atmosphere from any affected facility which combusts solid solvent refined coal (SRC-I) any... (1.2 lb/MWh) net energy output; or (iii) 3 percent of the potential combustion concentration (97...

40 CFR 60.43Da - Standards for sulfur dioxide (SO2).

Code of Federal Regulations, 2013 CFR

2013-07-01

... into the atmosphere from any affected facility which combusts solid solvent refined coal (SRC-I) any... (1.2 lb/MWh) net energy output; or (iii) 3 percent of the potential combustion concentration (97...

Development and certification of a coal fly ash certified reference material for selected polycyclic aromatic hydrocarbons.

PubMed

Cao, X; Xu, X; Cui, W; Xi, Z

2001-08-01

The development and certification of a coal fly ash certified reference material (CRM) for polycyclic aromatic hydrocarbons (PAH) is described; this is the first natural matrix CRM for organic environmental analysis in China. The homogeneity and stability of this material have been tested by HPLC. The concentrations of several PAH were determined by use of two independent, different methods--solvent extraction-HPLC analysis with UV detection coupled with fluorescence detection (FLD) and solvent extraction, isolation with a silica column, and GC analysis with flame ionization detection (FID). Five certified values were determined: phenanthrene 7.1 +/- 2.6 microg g(-1), anthracene 2.0 +/- 0.8 microg g(-1), fluoranthene 7.4 +/- 1.9 microg g(-1), pyrene 7 +/- 2 microg g(-1), and benzo[a]pyrene 1.3 +/- 0.3 microg g(-1). Reference values for several other PAH are also suggested.

Solid-state flurbiprofen and methyl-β-cyclodextrin inclusion complexes prepared using a single-step, organic solvent-free supercritical fluid process.

PubMed

Rudrangi, Shashi Ravi Suman; Kaialy, Waseem; Ghori, Muhammad U; Trivedi, Vivek; Snowden, Martin J; Alexander, Bruce David

2016-07-01

The aim of this study was to enhance the apparent solubility and dissolution properties of flurbiprofen through inclusion complexation with cyclodextrins. Especially, the efficacy of supercritical fluid technology as a preparative technique for the preparation of flurbiprofen-methyl-β-cyclodextrin inclusion complexes was evaluated. The complexes were prepared by supercritical carbon dioxide processing and were evaluated by solubility, differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, practical yield, drug content estimation and in vitro dissolution studies. Computational molecular docking studies were conducted to study the possibility of molecular arrangement of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin. The studies support the formation of stable molecular inclusion complexes between the drug and cyclodextrin in a 1:1 stoichiometry. In vitro dissolution studies showed that the dissolution properties of flurbiprofen were significantly enhanced by the binary mixtures prepared by supercritical carbon dioxide processing. The amount of flurbiprofen dissolved into solution alone was very low with 1.11±0.09% dissolving at the end of 60min, while the binary mixtures processed by supercritical carbon dioxide at 45°C and 200bar released 99.39±2.34% of the drug at the end of 30min. All the binary mixtures processed by supercritical carbon dioxide at 45°C exhibited a drug release of more than 80% within the first 10min irrespective of the pressure employed. The study demonstrated the single step, organic solvent-free supercritical carbon dioxide process as a promising approach for the preparation of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin in solid-state. Copyright © 2016 Elsevier B.V. All rights reserved.

Liquefaction of solid carbonaceous material with catalyst recycle

DOEpatents

Gupta, Avinash; Greene, Marvin I.

1992-01-01

In the two stage liquefaction of a carbonaceous solid such as coal wherein coal is liquefied in a first stage in the presence of a liquefaction solvent and the first stage effluent is hydrogenated in the presence of a supported hydrogenation catalyst in a second stage, catalyst which has been previously employed in the second stage and comminuted to a particle size distribution equivalent to 100% passing through U.S. 100 Mesh, is passed to the first stage to improve the overall operation.

SRC-I demonstration plant analytical laboratory methods manual. Final technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klusaritz, M.L.; Tewari, K.C.; Tiedge, W.F.

1983-03-01

This manual is a compilation of analytical procedures required for operation of a Solvent-Refined Coal (SRC-I) demonstration or commercial plant. Each method reproduced in full includes a detailed procedure, a list of equipment and reagents, safety precautions, and, where possible, a precision statement. Procedures for the laboratory's environmental and industrial hygiene modules are not included. Required American Society for Testing and Materials (ASTM) methods are cited, and ICRC's suggested modifications to these methods for handling coal-derived products are provided.

Steric effects on diffusion into bituminous coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

John W. Larsen; Doyoung Lee

2006-02-01

The reactions of maleic anhydride, cis-maleate esters, and acetylenedicarboxylate esters with Pittsburgh No. 8 or Illinois No. 6 coal using o-xylene or o-dichlorobenzene solvent are diffusion controlled. Diffusion is Fickian in all cases. The measured activation energies are between 5.4 and 7.6 kcal/mol. Diffusion rates decrease slowly with increasing alkyl chain length and sharply with branching. Diffusion rates are slightly faster with o-xylene than when o-dichlorobenzene is used. 40 refs., 5 figs., 4 tabs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsubara, Yasuo; Grills, David C.; Koide, Yoshihiro

Room-temperature ionic liquids (ILs) are a class of nonaqueous solvents that have expanded the realm of modern chemistry, drawing increasing interest over the last few decades, not only in terms of their own unique physical chemistry but also in many applications including organic synthesis, electrochemistry, and biological systems, wherein charged solutes (i.e., electrolytes) often play vital roles. But, our fundamental understanding of the dissolution of an electrolyte in an IL is still rather limited. For example, the activity of a charged species has frequently been assumed to be unity without a clear experimental basis. In this study, we have discussedmore » a standard component-based scheme for the dissolution of an electrolyte in an IL, supported by our observation of ideal Nernstian responses for the reduction of silver and ferrocenium salts in a representative IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim +][NTf 2 -] or [emim +][TFSI -]). Using this scheme, which was also supported by temperature-dependent measurements with ILs having longer alkyl chains in the imidazolium ring, and the solubility of the IL in water, we established the concept of Gibbs transfer energies of “pseudo-single ions” from the IL to conventional neutral molecular solvents (water, acetonitrile, and methanol). This concept, which bridges component- and constituent-based energetics, utilizes an extrathermodynamic assumption, which itself was justified by experimental observations. Furthermore, these energies enable us to eliminate inner potential differences between the IL and molecular solvents (solvent-solvent interactions), that is, on a practical level, conditional liquid junction potential differences, so that we can discuss ion-solvent interactions independently. Specifically, we have examined the standard electrode potential of the ferrocenium/ferrocene redox couple, Fc +/Fc, and the absolute intrinsic standard chemical potential of a proton in [emim +][NTf 2 -], finding that the proton is more acidic in the IL than in water by 6.5 ± 0.6 units on the unified pH scale. Finally, our results strengthen the progress on the physical chemistry of ions in IL solvent systems on the basis of their activities, providing a rigorous thermodynamic framework.« less

Feasibility of electrospray deposition for rapid screening of the cocrystal formation and single step, continuous production of pharmaceutical nanococrystals.

PubMed

Emami, Shahram; Siahi-Shadbad, Mohammadreza; Barzegar-Jalali, Mohammad; Adibkia, Khosro

2018-06-01

This study employed electrospray deposition (ESD) for simultaneous synthesis and particle engineering of cocrystals. Exploring new methods for the efficient production of cocrystals with desired particle properties is an essential demand. The possibility of cocrystal formation by ESD was examined for indomethacin-saccharin, indomethacin-nicotinamide, naproxen-nicotinamide, and naproxen-iso-nicotinamide cocrystals. Solutions of the drug and coformer at stoichiometric ratios were sprayed to a high electric field which caused rapid evaporation of the solvent and the formation of fine particles. The phase purity, size, and morphology of products were compared with reference cocrystals. Experiments were performed to evaluate the effects of stoichiometric ratio, concentration and solvent type on the cocrystal formation. Physical stability and dissolution properties of the electrosprayed cocrystals were also compared with reference cocrystals. ESD was found to be an efficient and rapid method to produce cocrystals for all studied systems other than indomethacin-nicotinamide. Pure cocrystals only formed at a specific drug:coformer ratio. The solvent type has a weak effect on the cocrystal formation and morphology. Electrosprayed cocrystals exhibited nano to micrometer sizes with distinct morphologies with comparable physical stability with reference cocrystals. Nanococrystals of indomethacin-saccharin with a mean size of 219 nm displayed a threefold higher dissolution rate than solvent evaporated cocrystal. ESD successfully was utilized to produce pure cocrystals of poorly soluble drugs with different morphologies and sizes ranging from nano to micrometer sizes in one step. This study highlighted the usefulness of ESD for simultaneous preparation and particle engineering of pharmaceutical cocrystals.

Colloidal transport phenomena of milk components during convective droplet drying.

PubMed

Fu, Nan; Woo, Meng Wai; Chen, Xiao Dong

2011-10-15

Material segregation has been reported for industrial spray-dried milk powders, which indicates potential material migration during drying process. The relevant colloidal transport phenomenon and the underlying mechanism are still under debate. This study extended the glass-filament single droplet drying technique to observe not only the drying behaviour but also the dissolution behaviour of the correspondingly dried single particle. At progressively longer drying stage, a solvent droplet (water or ethanol) was attached to the semi-dried milk particle and the interaction between the solvent and the particle was video-recorded. Based on the different dissolution and wetting behaviours observed, material migration during milk drying was studied. Fresh skim milk and fresh whole milk were investigated using water and ethanol as solvents. Fat started to accumulate on the surface as soon as drying was started. At the initial stage of drying, the fat layer remained thin and the solubility of the semi-dried milk particle was much affected by lactose and protein present underneath the fat layer. Fat kept accumulating at the surface as drying progressed and the accumulation was completed by the middle stage of drying. The results from drying of model milk materials (pure sodium caseinate solution and lactose/sodium caseinate mixed solution) supported the colloidal transport phenomena observed for the milk drying. When mixed with lactose, sodium caseinate did not form an apparent solvent-resistant protein shell during drying. The extended technique of glass-filament single droplet approach provides a powerful tool in examining the solubility of individual particle after drying. Copyright © 2011 Elsevier B.V. All rights reserved.

Understanding the dissolution of α-zein in aqueous ethanol and acetic acid solutions.

PubMed

Li, Yunqi; Li, Ji; Xia, Qiuyang; Zhang, Boce; Wang, Qin; Huang, Qingrong

2012-10-04

Zein is a corn prolamin that has broad industrial applications because of its unique physical properties. Currently, the high cost of extraction and purification, which is directly related to the dispersion of zein in different solvents, is the major bottleneck of the zein industry. Solution behaviors of zein have been studied for a long time. However, the physical nature of zein in different solvents remains unclear. In this study, small-angle X-ray scattering (SAXS), static light scattering (SLS), and rheology were combined to study the structure and protein-solvent interaction of α-zein in both acetic acid and aqueous ethanol solutions. We found that the like-dissolve-like rule, the partial unfolding, and the protonation of zein are all critical to understanding the solution behaviors. Zein holds an elongated conformation (i.e., prolate ellipsoid) in all solutions, as revealed from SAXS data. There is an "aging effect" for zein in aqueous ethanol solutions, as evidenced by the transition of Newtonian rheological profiles for fresh zein solutions to the non-Newtonian shear thinning behavior for zein solutions after storage at room temperature for 24 h. Such shear thinning behavior becomes more pronounced for zein solutions at higher concentrations. The SLS results clearly show that acetic acid is a better solvent to dissolve zein than aqueous ethanol solution, as supported by a more negative second virial coefficient. This is majorly caused by the protonation of the protein, which was further verified by the dissolution of zein in water (a nonsolvent for zein) with the addition of acids.

Coal fracturing and heteroatom removal. Annual report, fiscal year 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapienza, R.; Slegeir, W.; Butcher, T.

1983-09-01

Coal-water slurry fuels offer a practical, economical method to use coal, replacing the 3 million barrels of oil used per day to fuel utility boilers, industrial heaters, and furnaces in the US. The mineral matter and in some cases the costs of grinding are major impediments to the direct use of this fuel in existing fluid fuel combustors. A process for the simultaneous cleaning and fracturing of a variety of coals has been explored at Brookhaven National Laboratory. This process entails exposure of coal to a carbon dioxide-water solvent system under pressure. Substantial amounts of mineral matter are leached intomore » the liquid phase, significantly lowering the concentrations of alkaline, and alkaline earth metals, and of silica- and alumina-like minerals in the coal. Grindability studies have been conducted in a laboratory ball mill using processed coal. Grinding times for large-size feed coal (1-3/8 to 3/8 in.) are reduced by a factor up to 10 following exposure to CO/sub 2//water. With smaller-feed coal (4 x 8 mesh), however, improvements in grindability are much smaller. An integrated system has been constructed in which coal is ground while under CO/sub 2/ pressure. Significant improvements in grindability have been observed with this system, even with smaller-feed coal. 20 refs., 8 figs., 24 tabs.« less

Rate of coal hydroliquefaction: correlation to coal structure. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, R.M.; Voorhees, K.J.; Durfee, S.L.

This report summarizes the research carried out on DOE grant No. FG22-83PC60784. The work was divided into two phases. The first phase consisted of a series of coal liquefaction rate measurements on seven different coals from the Exxon sample bank, followed by correlation with parent coal properties. The second phase involved characterization of the coals by pyrolysis/mass spectrometry and subsequent correlations of the Py/MS patterns with various liquefaction reactivity parameters. The hydroliquefaction reactivities for a suite of 7 bituminous and subbituminous coals were determined on a kinetic basis. These reactivities were correlated fairly successfully with the following parent coal properties:more » volatile matter, H/C and O/C ratios, vitrinite reflectance, and calorific value. The total surface areas of the coals were experimentally determined. Reactivity was shown to be independent of surface area. Following completion of the batch reactor experiments, the seven coals investigated were analyzed by pyrolysis/mass spectrometry. The pyrolysis spectra were then submitted to factor analysis in order to extract significant features of the coal for use in correlational efforts. These factors were then related to a variety of liquefaction reactivity definitions, including both rate and extent of liquefaction to solvent solubility classifications (oils, asphaltenes, preasphaltenes, etc.). In general, extent of reaction was found to correlate best with the Py/MS data. 37 refs., 25 figs., 11 tabs.« less

How does low-molecular-weight polystyrene dissolve: osmotic swelling vs. surface dissolution.

PubMed

Marcon, Valentina; van der Vegt, Nico F A

2014-12-07

By means of multiscale hierarchical modeling we study the real time evolution of low-molecular-weight polystyrene, below the glass transition temperature, in contact with its solvent, toluene. We observe two concurrent phenomena taking place: (1) the solvent diffuses into the polymer by a Case II mechanism, leading to osmotic driven swelling and progressive chain dilution (inside-out mechanism); (2) polymer chains are solvated, detach from the interface and move into the solvent before the film is completely swollen (outside-in mechanism). From our simulations we conclude that, below the entanglement length, a thin swollen layer, also observed in previous experiments, forms almost instantaneously, which allows for the outside-in mechanism to start a few tens of nanoseconds after the polymer-solvent initial contact. After this initial transient time the two mechanisms are concurrent. We furthermore observe that the presence of the solvent significantly enhances the mobility of the polymer chains of the surface layer, but only in the direction parallel to the interface.

Extrusion of xylans extracted from corn cobs into biodegradable polymeric materials.

PubMed

Bahcegul, Erinc; Akinalan, Busra; Toraman, Hilal E; Erdemir, Duygu; Ozkan, Necati; Bakir, Ufuk

2013-12-01

Solvent casting technique, which comprises multiple energy demanding steps including the dissolution of a polymer in a solvent followed by the evaporation of the solvent from the polymer solution, is currently the main technique for the production of xylan based polymeric materials. The present study shows that sufficient water content renders arabinoglucuronoxylan (AGX) polymers extrudable, enabling the production of AGX based polymeric materials in a single step via extrusion, which is economically advantageous to solvent casting process for mass production. AGX polymers with water content of 27% were found to yield extrudates at an extrusion temperature of 90°C. The extruded strips showed very good mechanical properties with an ultimate tensile strength of 76 ± 6 MPa and elongation at break value of 35 ± 8%, which were superior to the mechanical properties of the strips obtained from polylactic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

Separation of polysaccharides from rice husk and wheat bran using solvent system consisting of BMIMOAc and DMI.

PubMed

Hou, Qidong; Li, Weizun; Ju, Meiting; Liu, Le; Chen, Yu; Yang, Qian; Wang, Jingyu

2015-11-20

A solvent system consisting of 1,3-dimethyl-2-imidazolidinone (DMI), and ionic liquid 1-butyl-3-methylimidazolium acetate (BMIMOAc) was used to separate polysaccharides from rice husk and wheat bran. The effects of the DMI/BMIMOAc ratios, temperature, and time on the dissolution of rice husk and wheat bran were investigated, and the influence of anti-solvents on the regeneration of polysaccharides-rich material was evaluated. We found that the solvent system is more powerful to dissolve rice husk and wheat bran than pure BMIMOAc, and that polysaccharides-rich material can be effectively separated from the biomass solution. The polysaccharides content of regenerated material from wheat bran can reach as high as 94.4% when ethanol was used as anti-solvents. Under optimized conditions, the extraction rate of polysaccharides for wheat bran can reach as high as 71.8% at merely 50°C. The recycled solvent system exhibited constant ability to separate polysaccharides from rice husk and wheat bran. Copyright © 2015 Elsevier Ltd. All rights reserved.

A mixed solvent system for preparation of spherically agglomerated crystals of ascorbic acid.

PubMed

Ren, Fuzheng; Zhou, Yaru; Liu, Yan; Fu, Jinping; Jing, Qiufang; Ren, Guobin

2017-09-01

The objective of this research was to develop a novel solvent system to prepare spherically agglomerated crystals (SAC) of ascorbic acid with improved flowability for direct compression. A spherical agglomeration method was developed by selecting the mixed solvents (n-butyl and ethyl acetate) as a poor solvent and the process was further optimized by using triangular phase diagram and particle vision measurement. Physiochemical properties of SAC were characterized and compared with original drug crystals. It showed that amount of poor solvent, ratio of solvent mixture, and drug concentration are critical for preparation of SAC with desirable properties. The solid state of SAC was same as original crystals according to DSC, XRD, and FT-IR results. There was no significant difference in solubility and dissolution rate of drug between SAC and original crystals. The flowability and packability of SAC as well as the tensile strength and elastic recovery of tablets made from SAC were all significantly improved when compared with original crystals and tablets from crystals. It is concluded that the present method was suitable to prepare SAC of ascorbic acid for direct compression.

Kinetics of dissolution of sapphire in melts in the CaO-Al2O3-SiO2 system

NASA Astrophysics Data System (ADS)

Shaw, Cliff S. J.; Klausen, Kim B.; Mao, Huahai

2018-05-01

The dissolution rate of sapphire in melts in the CAS system of varying silica activity, viscosity and degree of alumina saturation has been determined at 1600 °C and 1.5 GPa. After an initiation period of up to 1800 s, dissolution is controlled by diffusion of cations through the boundary layer adjacent to the dissolving sapphire. The dissolution rate decreases with increasing silica activity, viscosity and molar Al2O3/CaO. The calculated diffusion matrix for each solvent melt shows that CAS 1 and 9 which have molar Al2O3/CaO of 0.33 and 0.6 and dissolution rate constants of 0.65 × 10-6 and 0.59 × 10-6 m/s0.5 have similar directions and magnitudes of diffusive coupling: DCaO-Al2O3 and DAl2O3-CaO are both negative are approximately equal. The solvent with the fastest dissolution rate: CAS 4, which has a rate constant of 1.5 × 10-6 m/s0.5 and Al2O3/CaO of 0.31 has positive DCaO-Al2O3 and negative DAl2O3-CaO and the absolute values vary by a factor of 4. Although many studies show that aluminium is added to the melts via the reaction: Si4+ =Al3+ + 0.5Ca2+ the compositional profiles show that this reaction is not the only one involved in accommodating the aluminium added during sapphire dissolution. Rather, aluminium is incorporated as both tetrahedrally coordinated Al charge balanced by Ca and as aluminium not charge balanced by Ca (termed Alxs). This reaction: AlIV -Ca =Alxs +CaNBO where CaNBO is a non-bridging oxygen associated with calcium, may involve the formation of aluminium triclusters. The shape of the compositional profiles and oxide-oxide composition paths is controlled by the aluminium addition reaction. When Alxs exceeds 2%, CaO diffusion becomes increasingly anomalous and since the bond strength of Alxs correlates with CaO/CaO + Al2O3, the presence of more than 2% Alxs leads to significantly slower dissolution than when Alxs is absent or at low concentration. Thus, dissolution is controlled by diffusion of cations through the boundary layer, but this diffusion is itself controlled by the structural modifications required by the addition of new components to the melt. Comparison of quartz dissolution rates in similar melts shows that dissolution is much faster for quartz than for sapphire and that dissolution rates show the same correlation with silica activity and viscosity. We suggest that diffusive fluxes are related to changes in melt structure and the nature of the reaction that incorporates the added component. For the slow eigendirection, SiO2 addition occurs by a single reaction whereas Al2O3 addition requires a more complex two part reaction in which Al is accommodated by charge balance with Ca until Al is in excess of that which can be charge balanced. The Alxs incorporation reaction, is slower than the Si incorporation reaction which inhibits sapphire dissolution relative to quartz in melts of the same composition.

Anaerobic microbial dissolution of lead and production of organic acids

DOEpatents

Francis, Arokiasamy J.; Dodge, Cleveland; Chendrayan, Krishnachetty; Quinby, Helen L.

1988-01-01

The present invention relates to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rate of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 .mu.moles of lead as lead oxide was 0.042 .mu.moles ml.sup.-1 hr.sup.-1. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids.

Hydrobiogeochemical interactions in 'anoxic' limestone drains for neutralization of acidic mine drainage

USGS Publications Warehouse

Robbins, E.I.; Cravotta, C.A.; Savela, C.E.; Nord, G.L.

1999-01-01

Processes affecting neutralization of acidic coal mine drainage were evaluated within 'anoxic' limestone drains (ALDs). Influents had pH???3.5 and dissolved oxygen <2 mg/l. Even though effluents were near neutral (pH 6 and alkalinity acidity), two of the four ALDs were failing due to clogging. Mineral-saturation indices indicated the potential for dissolution of calcite and gypsum, and precipitation of Al3+ and Fe3+ compounds. Cleavage mounts of calcite and gypsum that were suspended within the ALDs and later examined microscopically showed dissolution features despite coatings by numerous bacteria, biofilms, and Fe-Al-Si precipitates. In the drain exhibiting the greatest flow reduction, Al-hydroxysulfates had accumulated on limestone surfaces and calcite etch points, thus causing the decline in transmissivity and dissolution. Therefore, where Al loadings are high and flow rates are low, a pre-treatment step is indicated to promote Al removal before diverting acidic mine water into alkalinity-producing materials. ?? 1998 Elsevier Science Ltd.

An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields. Quarterly progress report, January 1, 1994--March 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miknis, F.P.; Netzel, D.A.

The results of coal swelling measurements using 1,4-dioxane as the swelling reagent for premoisturized coals (raw) and coal dried thermally, chemically, and with microwave radiation are presented. An increase in the swelling ratio relative to raw coal indicates a decrease in the amount of cross-linking in the coal. Conversely, a decrease in the ratio indicates an increase in cross-linking. The extent of cross-linking (as measured by 1,4-dioxane) for Texas, Black Thunder, and Eagle Butte Coals are about the same. Illinois {number_sign}6 coal appears to have less cross-linking relative to the other three coals. These results are expected on the basismore » of coal rank. The increase in cross linking is most pronounced for coals dried thermally and with microwave radiation. A decrease in the swelling ratios for all four coals suggests that cross-linking had occurred possibly due to partial devolatilization process. However, low temperature, chemical dehydration of the coals causes only a small or no change in the internal structure for Texas and Illinois {number_sign}6 coals whereas a significant decrease in the cross-linking structure for the Black Thunder and Eagle Butte coals is observed. It is possible that the solvent (CH{sub 3}OH) and products resulting from the chemical dehydrating (acetone and methanol) occupy the surface sites that water had before the reaction and thus preventing cross-linking to occur. These reagents can also promote swelling of coals and may account for some of the decrease in the cross-linking of the coal structure observed for the chemically dried coals.« less

Novel Solvent System for Post Combustion CO{sub 2} Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Alfred; Brown, Nathan

2013-09-30

The purpose of this project was to evaluate the performance of ION’s lead solvent and determine if ION’s solvent candidate could potentially meet DOE’s target of achieving 90% CO{sub 2} Capture from a 550 MWe Pulverized Coal Plant without resulting in an increase in COE greater than 35%. In this project, ION’s lead solvent demonstrated a 65% reduction in regeneration energy and a simultaneous 35% reduction in liquid to gas ratio (L/G) in comparison to aqMEA at 90% CO{sub 2} capture using actual flue gas at 0.2 MWe. Results have clearly demonstrated that the ION technology is in line withmore » DOE performance expectations and has the potential to meet DOE’s performance targets in larger scale testing environments.« less

[Macromolecular aromatic network characteristics of Chinese power coal analyzed by synchronous fluorescence and X-ray diffraction].

PubMed

Ye, Cui-Ping; Feng, Jie; Li, Wen-Ying

2012-07-01

Coal structure, especially the macromolecular aromatic skeleton structure, has a strong influence on coke reactivity and coal gasification, so it is the key to grasp the macromolecular aromatic skeleton coal structure for getting the reasonable high efficiency utilization of coal. However, it is difficult to acquire their information due to the complex compositions and structure of coal. It has been found that the macromolecular aromatic network coal structure would be most isolated if small molecular of coal was first extracted. Then the macromolecular aromatic skeleton coal structure would be clearly analyzed by instruments, such as X-ray diffraction (XRD), fluorescence spectroscopy with synchronous mode (Syn-F), Gel permeation chromatography (GPC) etc. Based on the previous results, according to the stepwise fractional liquid extraction, two Chinese typical power coals, PS and HDG, were extracted by silica gel as stationary phase and acetonitrile, tetrahydrofuran (THF), pyridine and 1-methyl-2-pyrollidinone (NMP) as a solvent group for sequential elution. GPC, Syn-F and XRD were applied to investigate molecular mass distribution, condensed aromatic structure and crystal characteristics. The results showed that the size of aromatic layers (La) is small (3-3.95 nm) and the stacking heights (Lc) are 0.8-1.2 nm. The molecular mass distribution of the macromolecular aromatic network structure is between 400 and 1 130 amu, with condensed aromatic numbers of 3-7 in the structure units.

Dissolution enhancement of Deflazacort using hollow crystals prepared by antisolvent crystallization process.

PubMed

Paulino, A S; Rauber, G; Campos, C E M; Maurício, M H P; de Avillez, R R; Capobianco, G; Cardoso, S G; Cuffini, S L

2013-05-13

Deflazacort (DFZ), a derivate of prednisolone, is a poorly soluble drug which has been proposed to have major advantages over other corticosteroids. Poorly soluble drugs present limited bioavailability due to their low solubility and dissolution rate and several strategies have been developed in order to find ways to improve them. In general, pharmaceutical laboratories use a micronized process to reduce the particle size in order to increase the dissolution of the drugs. However, this process causes changes such as polymorphic transitions, particle agglomeration and a reduction in fluidity and wettability. These solid-state properties affect the dissolution behavior and stability performance of drugs. Crystallization techniques are widely used in the pharmaceutical industry and antisolvent crystallization has been used to obtain ultrafine particles. In this study, DFZ was investigated in terms of its antisolvent crystallization in different solvents and under various preparation conditions (methanol/water ratio, stirring and evaporation rate, etc.), in order to compare the physicochemical properties between crystallized samples and raw materials available on the Brazilian market with and without micronization. Crystalline structure, morphology, and particle size, and their correlation with the Intrinsic Dissolution Rate (IDR) and dissolution profile as relevant biopharmaceutical properties were studied. Crystallization conditions were achieved which provided crystalline samples of hollow-shaped crystals with internal channels, which increased the dissolution rate of DFZ. The antisolvent crystallization process allowed the formation of hollow crystals, which demonstrated a better dissolution profile than the raw material (crystalline and micronized), making this a promising technique as a crystallization strategy for improving the dissolution and thus the bioavailability of poorly soluble drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

The impact of solvent relative permittivity on the dimerisation of organic molecules well below their solubility limits: examples from brewed coffee and beyond.

PubMed

Bradley, Ellen S; Hendon, Christopher H

2017-03-22

The formation of aqueous intermolecular dimers is governed by both the nature and strength of the intermolecular interactions and the entropy of dissolution. The former interaction energies are determined by the polarity of the solvent and the functionality of the solute. Using quantum chemical methods, we probe the energetics of dimer formation of representative compounds found in coffee well below their solubility limits. We find that with the exclusion of entropy, the dimer formation is thermodynamically unfavorable with negligible dependence on the dielectric medium.

Impact of solvent extraction organics on adsorption and bioleaching of A. ferrooxidans and L. ferriphilum

NASA Astrophysics Data System (ADS)

Hualong, Yu; Xiaorong, Liu

2017-04-01

Copper solvent extraction entrained and dissoluted organics (SX organics) in the raffinate during SX operation can contaminated chalcopyrite ores and influence bioleaching efficiency by raffinate recycling. The adsorption and bioleaching of A. ferrooxidans and L. ferriphilum with contaminated ores were investigated. The results showed that, A. ferrooxidans and L. ferriphilum cells could adsorb quickly on minerals, the adsorption rate on contaminated ores were 83% and 60%, respectively, larger than on uncontaminated ores. However, in the bioleaching by the two kinds of acid bacterias, contaminated ores presented a lower bioleaching efficiency.

Impact of solvent extraction organics on bioleaching by Acidithiobacillus ferrooxidans

NASA Astrophysics Data System (ADS)

Yu, Hualong; Liu, Xiaorong; Shen, Junhui; Chi, Daojie

2017-03-01

Solvent extraction organics (SX organics) entrained and dissoluted in the raffinate during copper SX operation, can impact bioleaching in case of raffinate recycling. The influence of SX organics on bioleaching process by Acidithiobacillus ferrooxidans (At. ferrooxidans) has been investigated. The results showed that, cells of At. ferrooxidans grew slower with contaminated low-grade chalcopyrite ores in shaken flasks bioleaching, the copper bioleaching efficiency reached 15%, lower than that of 24% for uncontaminated minerals. Obviously, the SX organics could adsorb on mineral surface and hinder its contact with bacterials, finanlly lead to the low bioleaching efficiency.

Disposable rabbit

DOEpatents

Lewis, Leroy C.; Trammell, David R.

1986-01-01

A disposable rabbit for transferring radioactive samples in a pneumatic transfer system comprises aerated plastic shaped in such a manner as to hold a radioactive sample and aerated such that dissolution of the rabbit in a solvent followed by evaporation of the solid yields solid waste material having a volume significantly smaller than the original volume of the rabbit.

Disposal rabbit

DOEpatents

Lewis, L.C.; Trammell, D.R.

1983-10-12

A disposable rabbit for transferring radioactive samples in a pneumatic transfer system comprises aerated plastic shaped in such a manner as to hold a radioactive sample and aerated such that dissolution of the rabbit in a solvent followed by evaporation of the solid yields solid waste material having a volume significantly smaller than the original volume of the rabbit.

Accounting for Mass Transfer Kinetics when Modeling the Impact of Low Permeability Layers in a Groundwater Source Zone on Dissolved Contaminant Fate and Transport

DTIC Science & Technology

2014-03-27

Clay Interface) ...................................................................................................... 40 Figure 9: Time-Dependent...vs Constant Dissolution Rate BTCs (Monitoring Well in Clay ...pits, poured down sanitary sewer systems, and partially burned in fire training pits. Poor handling and disposal of chlorinated solvents have

Electrospun zein fibers using glyoxal as the cross-linking reagent

USDA-ARS?s Scientific Manuscript database

Glyoxal has been used to provide zein electrospun fibers that are resistant to dissolution by known zein solvents. Durable fibers with diameters between 0.2 and 0.7 micrometers could be produced. The reaction between zein and glyoxal was carried out in acetic acid at temperatures between 25 and 60...

Physicochemical characterization of Capstone depleted uranium aerosols IV: in vitro solubility analysis.

PubMed

Guilmette, Raymond A; Cheng, Yung Sung

2009-03-01

As part of the Capstone Depleted Uranium (DU) Aerosol Study, the solubility of selected aerosol samples was measured using an accepted in vitro dissolution test system. This static system was employed along with a SUF (synthetic ultrafiltrate) solvent, which is designed to mimic the physiological chemistry of extracellular fluid. Using sequentially obtained solvent samples, the dissolution behavior over a 46-d test period was evaluated by fitting the measurement data to two- or three-component negative exponential functions. These functions were then compared with Type M and S absorption taken from the International Commission on Radiological Protection Publication 66 Human Respiratory Tract Model. The results indicated that there was a substantial variability in solubility of the aerosols, which in part depended on the type of armor being impacted by the DU penetrator and the particle size fraction being tested. Although some trends were suggested, the variability noted leads to uncertainties in predicting the solubility of other DU-based aerosols. Nevertheless, these data provide a useful experimental basis for modeling the intake-dose relationships for inhaled DU aerosols arising from penetrator impact on armored vehicles.

Cocrystals of acyclovir with promising physicochemical properties.

PubMed

Sarkar, Anindita; Rohani, Sohrab

2015-01-01

Cocrystal forming ability of antiviral drug acyclovir (ACV) with different coformers was studied. Three cocrystals containing ACV with fumaric acid, malonic acid, and DL-tartaric acid were isolated. Methods of cocrystallization included grinding with dropwise solvent addition and solvent evaporation. The cocrystals were characterized by powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The crystal structure of the cocrystal with fumaric acid as conformer was determined by single crystal X-ray diffraction. Formation of supramolecular synthon was observed in the cocrystal. Stability with respect to relative humidity for the three cocrystals was evaluated. The aqueous solubility of the ACV-cocrystal materials was significantly improved with a maximum of malonic acid cocrystal, which was about six times more soluble at 35°C compared with that of parent ACV. The dissolution profile indicates that at any particular dissolution time, the concentration of cocrystals in the solution was higher than that of the parent ACV, and malonic acid cocrystals had a maximum release of about twice than the hydrated ACV. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Preparation and physicochemical characterization of 5 niclosamide solvates and 1 hemisolvate.

PubMed

van Tonder, Elsa C; Mahlatji, Mabatane D; Malan, Sarel F; Liebenberg, Wilna; Caira, Mino R; Song, Mingna; de Villiers, Melgardt M

2004-02-23

The purpose of the study was to characterize the physicochemical, structural, and spectral properties of the 1:1 niclosamide and methanol, diethyl ether, dimethyl sulfoxide, N,N' dimethylformamide, and tetrahydrofuran solvates and the 2:1 niclosamide and tetraethylene glycol hemisolvate prepared by recrystallization from these organic solvents. Structural, spectral, and thermal analysis results confirmed the presence of the solvents and differences in the structural properties of these solvates. In addition, differences in the activation energy of desolvation, batch solution calorimetry, and the aqueous solubility at 25 degrees C, 24 hours, showed the stability of the solvates to be in the order: anhydrate > diethyl ether solvate > tetraethylene glycol hemisolvate > methanol solvate > dimethyl sulfoxide solvate > N,N' dimethylformamide solvate. The intrinsic and powder dissolution rates of the solvates were in the order: anhydrate > diethyl ether solvate > tetraethylene glycol hemisolvate > N,N' dimethylformamide solvate > methanol solvate > dimethyl sulfoxide solvate. Although these nonaqueous solvates had higher solubility and dissolution rates than the monohydrous forms, they were unstable in aqueous media and rapidly transformed to one of the monohydrous forms.

Physicochemical characterization of solid dispersions of carbamazepine formulated by supercritical carbon dioxide and conventional solvent evaporation method.

PubMed

Sethia, Sundeep; Squillante, Emilio

2002-09-01

Solid dispersions of carbamazepine (CBZ) were formulated by supercritical fluid processing (SCP) and conventional solvent evaporation in polyethylene glycol (PEG) 8000 with either Gelucire 44/14 or vitamin E TPGS NF (d-alpha-tocopheryl PEG 1000 succinate). Formulations were evaluated by dissolution, scanning electron microscopy, powder X-ray diffraction, and differential scanning calorimetry, and excipient cytotoxicity in Caco-2 cells by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay. CBZ release was enhanced from supercritical fluid-treated CBZ and the CBZ/PEG 8000 (1:5), CBZ/PEG 8000/TPGS or Gelucire 44/14 (1:4:1) solid dispersions. The radically altered morphologies of SCP samples seen by scanning electron microscopy suggested polymorphic change that was confirmed by the X-ray diffraction and differential scanning calorimetry. Disappearance of the characteristic CBZ melting peak indicated that CBZ was dissolved inside the carrier system. Polymorphic change of CBZ during SCP led to faster dissolution. Therefore, SCP provides advantages over solid dispersions prepared by conventional processes. Copyright 2002 Wiley-Liss Inc.

[Efficient Pharmaceutical Formulation Designs and Their Development Using Mathematical and Statistical Analysis].

PubMed

Iwao, Yasunori

2015-01-01

With the aim of directly predicting the functionality and mechanism of pharmaceutical excipients, we investigated an analysis method based on available surface area (S(t)), which is the surface area of a drug in direct contact with the external solvent during dissolution. First, to study the effect of lubricant concentration on the dissolution rate of acetaminophen (APAP), the dissolution behaviors as well as the change over time in S(t) of APAP tablets were examined. In the dissolution tests, a retarded dissolution of APAP was not observed with new lubricant triglycerin full behenate (TR-FB), whereas magnesium stearate (Mg-St) retarded the dissolution. The S(t) profiles for APAP with Mg-St at>0.5% showed downward curvature indicating a gradual decrease in surface area over time. Conversely, with TR-FB, even when its concentration was increased, the S(t) profile for APAP had a maximum value. The differences between Mg-St and TR-FB could be explained by the differences in extensibility deriving from their morphology. Next, we evaluated the effect of disintegtant concentration using five disintegrants. When disintegrant was added to ethenzamide tablet formulation, an increase in the dissolution rate and S(t) dependent on disintegrant concentration was observed, according to the type of disintegrant. It was found that the water absorption ability of disintegrants had strong correlations with the parameters of S(t). Taken together, this study demonstrates that analysis of S(t) can directly provide useful information, especially about the functionality of pharmaceutical excipients.

"Cleaning" the Surface of Hydroxyapatite Nanorods by a Reaction-Dissolution Approach.

PubMed

Cao, Binrui; Yang, Mingying; Wang, Lin; Xu, Hong; Zhu, Ye; Mao, Chuanbin

2015-10-21

Synthetic nanoparticles are always terminated with coating molecules, which are often cytotoxic and not desired in biomedicine. Here we propose a novel reaction-dissolution approach to remove the cytotoxic coating molecules. A two-component solution is added to the nanoparticle solution; one component reacts with the coating molecules to form a salt whereas another is a solvent for dissolving and thus removing the salt. As a proof of concept, this work uses a NaOH-ethanol solution to remove the cytotoxic linoleic acid molecules coated on the hydroxyapatite nanorods (HAP-NRs). The removal of the coating molecules not only significantly improves the biocompatibility of HAP-NRs but also enables their oriented attachment into tightly-bound superstructures, which mimic the organized HAP crystals in bone and enamel and can promote the osteogenic differentiation of mesenchymal stem cells. Our reaction-dissolution approach can be extended to the surface "cleaning" of other nanomaterials.

Enhanced oral bioavailability of glycyrrhetinic acid via nanocrystal formulation.

PubMed

Lei, Yaya; Kong, Yindi; Sui, Hong; Feng, Jun; Zhu, Rongyue; Wang, Wenping

2016-10-01

The purpose of this study was to prepare solid nanocrystals of glycyrrhetinic acid (GA) for improved oral bioavailability. The anti-solvent precipitation-ultrasonication method followed by freeze-drying was adopted for the preparation of GA nanocrystals. The physicochemical properties, drug dissolution and pharmacokinetic of the obtained nanocrystals were investigated. GA nanocrystals showed a mean particle size of 220 nm and shaped like short rods. The analysis results from differential scanning calorimetry and X-ray powder diffraction indicated that GA remained in crystalline state despite a huge size reduction. The equilibrium solubility and dissolution rate of GA nanocrystal were significantly improved in comparison with those of the coarse GA or the physical mixture. The bioavailability of GA nanocrystals in rats was 4.3-fold higher than that of the coarse GA after oral administration. With its rapid dissolution and absorption performance, the solid nanocrystal might be a more preferable formulation for oral administration of poorly soluble GA.

First-Principles and Thermodynamic Simulation of Elastic Stress Effect on Energy of Hydrogen Dissolution in Alpha Iron

NASA Astrophysics Data System (ADS)

Rakitin, M. S.; Mirzoev, A. A.; Mirzaev, D. A.

2018-04-01

Mobile hydrogen, when dissolving in metals, redistributes due to the density gradients and elastic stresses, and enables destruction processes or phase transformations in local volumes of a solvent metal. It is rather important in solid state physics to investigate these interactions. The first-principle calculations performed in terms of the density functional theory, are used for thermodynamic simulation of the elastic stress effect on the energy of hydrogen dissolution in α-Fe crystal lattice. The paper presents investigations of the total energy of Fe-H system depending on the lattice parameter. As a result, the relation is obtained between the hydrogen dissolution energy and stress. A good agreement is shown between the existing data and simulation results. The extended equation is suggested for the chemical potential of hydrogen atom in iron within the local stress field. Two parameters affecting the hydrogen distribution are compared, namely local stress and phase transformations.

The differences between the branded and generic medicines using solid dosage forms: In-vitro dissolution testing

PubMed Central

Al Ameri, Mubarak Nasser; Nayuni, Nanda; Anil Kumar, K.G.; Perrett, David; Tucker, Arthur; Johnston, Atholl

2011-01-01

Introduction Dissolution is the amount of substance that goes into solution per unit time under standardised conditions of liquid/solid interface, solvent composition and temperature. Dissolution is one of the most important tools to predict the in-vivo bioavailability and in some cases to determine bioequivalence and assure interchangeability. Aim To compare the differences in dissolution behaviour of solid dosage forms between innovators (reference products) and their generic counterparts (tested products). Methods Four replicates for each batch of 37 tested medicines was carried out using A PT-DT70 dissolution tester from Pharma Test. A total of 13 branded medicines and 24 generic counterparts were obtained locally and internationally to detect any differences in their dissolution behaviour. They were tested according to the British Pharmacopeia, European Pharmacopeia and the US Pharmacopeia with the rate of dissolution determined by ultra-violet Spectrophotometery. Results Most tested medicines complied with the pharmacopoeial specifications and achieved 85% dissolution in 60 min. However, some generic medicines showed significant differences in dissolution rate at 60 and 120 min. Many generic medicines showed a slower dissolution rate than their branded counterparts such as the generic forms of omeprazole 20 mg. Some showed an incomplete dissolution such as the generic form of nifedipine 10 mg. Other generics showed faster dissolution rate than their branded counterpart such as the generic forms of meloxicam 15 mg. Moreover, some generics from different batches of the same manufacturer showed significant differences in their dissolution rate such as the generic forms of meloxicam 7.5 mg. Nevertheless, some generic medicines violated the EMA and the FDA guidelines for industry when they failed to achieve 85% dissolution at 60 min, such as the generic form of diclofenac sodium 50 mg. Conclusion Most medicines in this study complied with the pharmacopeial limits. However, some generics dissolved differently than their branded counterparts. This can clearly question the interchangeability between the branded and its generic counterpart or even among generics. PMID:25755988

Phase-Change Aminopyridines as Carbon Dioxide Capture Solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malhotra, Deepika; Page, Jordan P.; Bowden, Mark E.

Carbon dioxide is the main atmospheric greenhouse gas released from industrial point sources. In order to mitigate adverse environmental effects of these emissions, carbon capture, storage and utilization is required. To this end, several CO2 capture technologies are being developed for application in carbon capture, which include aqueous amines and water-lean solvents. Herein we report new aminopyridine solvents with the potential for CO2 capture from coal-fired power plants. These four solvents 2-picolylamine, 3-picolylamine, 4-picolylamine and N’-(pyridin-4-ylmethyl)ethane-1,2-diamine are liquids that rapidly bind CO2 to form crystalline solids at standard room temperature and pressure. These solvents have displayed high CO2 capture capacitymore » (11 - 20 wt%) and can be regenerated at temperatures in the range of 120 - 150 C. The advantage of these primary aminopyridine solvents is that crystalline salt product can be separated, making it possible to regenerate only the CO2-rich solid ultimately resulting in reduced energy penalty.« less

Optimization of diclofenac sodium profile from halloysite nanotubules.

PubMed

Krejčová, Kateřina; Deasy, Patrick B; Rabišková, Miloslava

2013-04-01

Halloysite, aluminosilicate clay with the particle shape of multilayered hollow nanotubes, used in various non-medical applications, e.g. in ceramic industry, was discovered for pharmaceutical purposes in recent years. Several drugs of hydrophilic and lipophilic nature have been successfully encapsulated into halloysite tubules in order to modify their dissolution profile. The main goal of this experiment was to optimize the dissolution profile of diclofenac sodium - a drug with problematic solubility - from halloysite tubules using various polymers. Loading of the drug together with povidone or Eudragit® RS did not lead to drug burst effect reduction and its slower dissolution. In the case of povidone, drug improved wettability and solubilization rather than viscosity increasing expectations were observed. Eudragit® RS formed a solid dispersion with diclofenac sodium and thus the solvent/drug solution penetration through the polymer and not the drug solubility was the dissolution rate limiting factor. Reduction of the burst effect and further prolongation of drug release was achieved by coating the drug-loaded halloysite with chitosan. This formulation exhibited a diffusion-controlled prolonged release following Higuchi kinetic model.

Increasing dissolution of trospium chloride by co-crystallization with urea

NASA Astrophysics Data System (ADS)

Skořepová, Eliška; Hušák, Michal; Čejka, Jan; Zámostný, Petr; Kratochvíl, Bohumil

2014-08-01

The search for various solid forms of an active pharmaceutical ingredient (API) is an important step in drug development. Our aim was to prepare co-crystals of trospium chloride, an anticholinergic drug used for the treatment of incontinence, and to investigate if they have advantageous properties for drug formulation. Phase identification was done by powder X-ray diffraction and single-crystal X-ray diffraction. The chemical composition was verified by solution NMR and the dissolution rate of the prepared phases was studied by IDR (intrinsic dissolution rate). For further analysis of phase stability and transitions, combined thermal analysis and temperature-resolved X-ray powder diffraction were used. Urea was selected as a co-crystallization partner. Trospium chloride urea (1:1) co-crystal was prepared by a solvent evaporation. From single-crystal data, the co-crystal structure was solved in a space group P21/c and compared to previously published structures of trospium chloride. Intrinsic dissolution rate revealed that the co-crystal dissolves 32% faster than pure API. However, its low thermal and pressure stability makes it a challenging choice for the final drug formulation.

Towards a molecular understanding of cellulose dissolution in ionic liquids: anion/cation effect, synergistic mechanism and physicochemical aspects.

PubMed

Li, Yao; Wang, Jianji; Liu, Xiaomin; Zhang, Suojiang

2018-05-07

Cellulose is one of the most abundant bio-renewable materials on the earth and its conversion to biofuels provides an appealing way to satisfy the increasing global energy demand. However, before carrying out the process of enzymolysis to glucose or polysaccharides, cellulose needs to be pretreated to overcome its recalcitrance. In recent years, a variety of ionic liquids (ILs) have been found to be effective solvents for cellulose, providing a new, feasible pretreatment strategy. A lot of experimental and computational studies have been carried out to investigate the dissolution mechanism. However, many details are not fully understood, which highlights the necessity to overview the current knowledge of cellulose dissolution and identify the research trend in the future. This perspective summarizes the mechanistic studies and microscopic insights of cellulose dissolution in ILs. Recent investigations of the synergistic effect of cations/anions and the distinctive structural changes of cellulose microfibril in ILs are also reviewed. Besides, understanding the factors controlling the dissolution process, such as the structure of anions/cations, viscosity of ILs, pretreatment temperature, heating rate, etc. , has been discussed from a structural and physicochemical viewpoint. At the end, the existing problems are discussed and future prospects are given. We hope this article would be helpful for deeper understanding of the cellulose dissolution process in ILs and the rational design of more efficient and recyclable ILs.

Towards a molecular understanding of cellulose dissolution in ionic liquids: anion/cation effect, synergistic mechanism and physicochemical aspects

PubMed Central

Li, Yao; Wang, Jianji

2018-01-01

Cellulose is one of the most abundant bio-renewable materials on the earth and its conversion to biofuels provides an appealing way to satisfy the increasing global energy demand. However, before carrying out the process of enzymolysis to glucose or polysaccharides, cellulose needs to be pretreated to overcome its recalcitrance. In recent years, a variety of ionic liquids (ILs) have been found to be effective solvents for cellulose, providing a new, feasible pretreatment strategy. A lot of experimental and computational studies have been carried out to investigate the dissolution mechanism. However, many details are not fully understood, which highlights the necessity to overview the current knowledge of cellulose dissolution and identify the research trend in the future. This perspective summarizes the mechanistic studies and microscopic insights of cellulose dissolution in ILs. Recent investigations of the synergistic effect of cations/anions and the distinctive structural changes of cellulose microfibril in ILs are also reviewed. Besides, understanding the factors controlling the dissolution process, such as the structure of anions/cations, viscosity of ILs, pretreatment temperature, heating rate, etc., has been discussed from a structural and physicochemical viewpoint. At the end, the existing problems are discussed and future prospects are given. We hope this article would be helpful for deeper understanding of the cellulose dissolution process in ILs and the rational design of more efficient and recyclable ILs. PMID:29780532

Effects of selective handling of pyritic, acid-forming materials on the chemistry of pore gas and ground water at a reclaimed surface coal mine in Clarion County, PA, USA

USGS Publications Warehouse

Cravotta,, Charles A.; Dugas, Diana L.; Brady, Keith; Kovalchuck, Thomas E.

1994-01-01

A change from dragline to “selective handling” mining methods at a reclaimed surface coal mine in western Pennsylvania did not significantly affect concentrations of metals in ground water because oxidation of pyrite and dissolution of siderite were not abated. Throughout the mine, placement of pyritic material near the land surface facilitated the oxidation of pyrite, causing the consumption of oxygen (O2) and release of acid, iron, and sulfate ions. Locally in the unsaturated zone, water sampled within or near pyritic zones was acidic, with concentrations of sulfate exceeding 3,000 milligrams per liter (mg/L). However, acidic conditions generally did not persist below the water table because of neutralization by carbonate minerals. Dissolution of calcite, dolomite, and siderite in unsaturated and saturated zones produced elevated concentrations of carbon dioxide (CO2), alkalinity, calcium, magnesium, iron, and manganese. Alkalinity concentrations of 600 to 800 mg/L as CaCO3 were common in water samples from the unsaturated zone in spoil, and alkalinities of 100 to 400 mg/L as CaCO3 were common in ground-water samples from the underlying saturated zone in spoil and bedrock. Saturation indices indicated that siderite could dissolve in water throughout the spoil, but that calcite dissolution or precipitation could occur locally. Calcite dissolution could be promoted as a result of pyrite oxidation, gypsum precipitation, and calcium ion exchange for sodium. Calcite precipitation could be promoted by evapotranspiration and siderite dissolution, and corresponding increases in concentrations of alkalinity and other solutes. Partial pressures of O2 (Po2) and CO2 (Pco2) in spoil pore gas indicated that oxidation of pyrite and precipitation of ferric hydroxide, coupled with dissolution of calcite, dolomite, and siderite were the primary reactions affecting water quality. Highest vertical gradients in Po2, particularly in the near-surface zone (0-1 m), did not correlate with concentrations of total sulfur in spoil. This lack of correlation could indicate that total sulfur concentrations in spoil do not reflect the amount of reactive pyrite or that oxidation rates can be controlled more by rates of O2 diffusion than the amount of pyrite. Hence, if placed in O2-rich zones near the land surface, even small amounts of disseminated pyritic material can be relatively significant sources of acid and mineralized water.

Tannate complexes of antihistaminic drug: sustained release and taste masking approaches.

PubMed

Rahman, Ziyaur; Zidan, Ahmed S; Berendt, Robert T; Khan, Mansoor A

2012-01-17

The aim of this investigation was to evaluate the complexation potential of brompheniramine maleate (BPM) and tannic acid (TA) for sustained release and taste masking effects. The complexes (1:1-1:7 TA to BPM ratio) were prepared by the solvent evaporation method using methanol, phosphate buffer pH 6.8 or 0.1N HCl as common solvents. The complexes were characterized microscopically by scanning electron microscopy (SEM), chemically by Fourier transform infrared (FTIR) and solid-state NMR (SSNMR), thermally by differential scanning calorimetry (DSC), for crystallinity by powder X-ray powder diffraction (PXRD), for organoleptic evaluation by electronic tongue (e-tongue), and for solubility in 0.1N HCl and phosphate buffer pH 6.8. The dissolution studies were carried out using the USP II method at 50 rpm in 500 ml of dissolution media (0.1N HCl or phosphate buffer pH 6.8). SEM images revealed that the morphology of complexes were completely different from the individual components, and all complexes had the same morphological characteristics, irrespective of the solvent used for their preparation, pH or ratio of BPM and TA. The FTIR spectra showed the presence of chemical interactions between the TA and BPM. DSC, PXRD and SSNMR indicated that the drug lost its crystalline nature by formation of the complex. Complexation has significantly reduced the solubility of BPM and sustained the drug release up to 24h in phosphate buffer pH 6.8 media. The bitter taste of the BPM was completely masked which was indicated by Euclidean distance values which was far from the drug but near to its placebo in the complexes in all ratios studied. The taste masked complexes can be potentially developed as suitable dosage forms for pediatric use. In summary, complexation of BPM and TA effectively sustained the dissolution and masked the bitter taste of drug for the development of suitable dosage forms for pediatric use. Published by Elsevier B.V.

Significance of excipients to enhance the bioavailability of poorly water-soluble drugs in oral solid dosage forms: A Review

NASA Astrophysics Data System (ADS)

Vadlamudi, Manoj Kumar; Dhanaraj, Sangeetha

2017-11-01

Nowadays most of the drug substances are coming into the innovation pipeline with poor water solubility. Here, the influence of excipients will play a significant role to improve the dissolution of poorly aqueous soluble compounds. The drug substance needs to be dissolved in gastric fluids to get the better absorption and bioavailability of an orally administered drug. Dissolution is the rate-controlling stage for drugs which controls the rate and degree of absorption. Usually, poorly soluble oral administrated drugs show a slower dissolution rate, inconsistent and incomplete absorption which can lead to lower bioavailability. The low aqueous solubility of BCS class II and IV drugs is a major challenge in the drug development and delivery process. Several technologies have been used in an attempt to progress the bioavailability of poorly water-soluble drug compounds which include solid dispersions, lipid-based formulations, micronization, solvent evaporation, co-precipitation, ordered mixing, liquid-solid compacts, solvent deposition inclusion complexation, and steam aided granulation. In fact, most of the technologies require excipient as a carrier which plays a significant role in improving the bioavailability using Hypromellose acetate succinate, Cyclodextrin, Povidone, Copovidone, Hydroxypropyl cellulose, Hydroxypropyl methylcellulose, Crospovidone, Starch, Dimethylacetamide, Polyethylene glycol, Sodium lauryl sulfate, Polysorbate, Poloxamer. Mesoporous silica and so on. This review deliberates about the excipients significance on bioavailability enhancement of drug products in a single platform along with pragmatically proved applications so that user can able to select the right excipients as per the molecule.

New chemolysis for urological calcium phosphate calculi – a study in vitro

PubMed Central

Xiang-bo, Zhang; Zhi-ping, Wang; Jian-min, Duan; Jian-zhong, Lu; Bao-liang, Ma

2005-01-01

Background Advances in techniques have left very few indications for open surgical extraction of urinary stones currently. These advances notwithstanding, the search continues for medical approaches to urinary stone management. In this study, we perform an in vitro study analyzing the efficiency and prospect of two new complex solutions in urological calcium phosphate calculi dissolution. Methods Eighteen stones composed mainly of calcium phosphates were taken from patients who underwent kidney stone surgery. These stones were large enough (weight range 0.514–0.928 g) to be fragmented and matched equally into six groups. Chemolysis of phosphate stones was done with six different solvents and was repeated 3 times with 6 stones for each solution. At 24, 48 and 72 h, reduction in weight, percentage weight change, and dissolution rate; the dissolution rates at pH 5.0, 7.0 and 8.5 for each solution, using different cations (Na+, K+ or Ca2+), according to different dilutions (1:1, 1:2, 1:3, 1:4) of S1 and S2 were simultaneously determined. Results Calcium phosphate calculi were poorly dissolved by Phys and Art, and they had a low dissolution rate in pH 8.5 EDTA. The most effective solutions were S1, S2 and R, with 72 h mean dissolution rates: 5.75 ± 0.44 mg/hr (S1), 5.2 ± 0.63 mg/hr (S2), 4.55 ± 0.46 mg/hr (R) ( ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA; p < 0.05, S1 vs R, LSD-test). The mean percentage weight loss at 72 h was: 52.1 ± 15.75 % (S1), 44.4 ± 7.37 % (S2) and 40.5 ± 3.67 % (R) ( ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA, LSD-test). Diluted twice, S1 and S2 had even better effectiveness than their initial solution. The additive of Na+, K+ or Ca2+ greatly reduced the dissolution rates of S1, S2. Conclusion Our data indicate that test solutions S1 and S2 are effective solvents in the chemolysis of calcium phosphate stones. At twice dilutions, these solutions are even more useful in the treatment of stone disease. PMID:15907215

Allotropic control: How certain fluorinated carbonate electrolytes protect aluminum current collectors by promoting the formation of insoluble coordination polymers

DOE PAGES

Shkrob, Ilya A.; Pupek, Krzysztof Z.; Abraham, Daniel P.

2016-07-28

Here, there is a strong incentive for increasing the operation voltage of Li-ion cells above 4.5 V in order to increase the density of stored energy. Aluminum is an inexpensive, lightweight metal that is commonly used as a positive electrode current collector in these cells. Imide LiX salts, such as lithium bis(trifluoromethylsulfonyl)imide (X = TFSI), and lithium bis(fluorosulfonyl)imide (X = FSI), are chemically stable on the energized lithiated transition metal oxide electrodes, but their presence in the electrolyte causes rapid anodic dissolution and pitting of Al current collectors at potentials exceeding 4.0 V versus Li/Li +. For LiBF 4 andmore » LiPF 6, the release of HF near the energized surfaces passivates the exposed Al metal, inhibiting this pitting corrosion, but it also causes the gradual degradation of the cathode active material, negating this important advantage. Here we report that in certain electrolytes containing fluorinated carbonate solvents and LiX salts, the threshold voltage for safe operation of Al current collectors can be increased to 5.5 V versus Li/Li +. Interestingly, the most efficient solvent also facilitates the formation of an insoluble gel when AlX 3 is introduced into this solvent. We suggest that this solvent promotes the aggregation of coordination polymers of AlX 3 at the exposed Al surface that isolate this surface from the electrolyte, thereby preventing further Al dissolution and corrosion. Other examples of Al collector protection may also involve this mechanism. Our study suggests that such “allotropic control” could be a way of widening the operation window of Li-ion cells without electrode deterioration, Al current collector corrosion, and electrolyte breakdown.« less

High drug load, stable, manufacturable and bioavailable fenofibrate formulations in mesoporous silica: a comparison of spray drying versus solvent impregnation methods.

PubMed

Hong, Shiqi; Shen, Shoucang; Tan, David Cheng Thiam; Ng, Wai Kiong; Liu, Xueming; Chia, Leonard S O; Irwan, Anastasia W; Tan, Reginald; Nowak, Steven A; Marsh, Kennan; Gokhale, Rajeev

2016-01-01

Encapsulation of drugs in mesoporous silica using co-spray drying process has been recently explored as potential industrial method. However, the impact of spray drying on manufacturability, physiochemical stability and bioavailability in relation to conventional drug load processes are yet to be fully investigated. Using a 2(3) factorial design, this study aims to investigate the effect of drug-loading process (co-spray drying and solvent impregnation), mesoporous silica pore size (SBA-15, 6.5 nm and MCM-41, 2.5 nm) and percentage drug load (30% w/w and 50% w/w) on material properties, crystallinity, physicochemical stability, release profiles and bioavailability of fenofibrate (FEN) loaded into mesoporous silica. From the scanning electronic microscopy (SEM) images, powder X-ray diffraction and Differential scanning calorimetry measurements, it is indicated that the co-spray drying process was able to load up to 50% (w/w) FEN in amorphous form onto the mesoporous silica as compared to the 30% (w/w) for solvent impregnation. The in vitro dissolution rate of the co-spray dried formulations was also significantly (p = 0.044) better than solvent impregnated formulations at the same drug loading. Six-month accelerated stability test at 40 °C/75 RH in open dish indicated excellent physical and chemical stability of formulations prepared by both methods. The amorphous state of FEN and the enhanced dissolution profiles were well preserved, and very low levels of degradation were detected after storage. The dog data for the three selected co-spray-dried formulations revealed multiple fold increment in FEN bioavailability compared to the reference crystalline FEN. These results validate the viability of co-spray-dried mesoporous silica formulations with high amorphous drug load as potential drug delivery systems for poorly water soluble drugs.

Allotropic control: How certain fluorinated carbonate electrolytes protect aluminum current collectors by promoting the formation of insoluble coordination polymers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shkrob, Ilya A.; Pupek, Krzysztof Z.; Abraham, Daniel P.

Here, there is a strong incentive for increasing the operation voltage of Li-ion cells above 4.5 V in order to increase the density of stored energy. Aluminum is an inexpensive, lightweight metal that is commonly used as a positive electrode current collector in these cells. Imide LiX salts, such as lithium bis(trifluoromethylsulfonyl)imide (X = TFSI), and lithium bis(fluorosulfonyl)imide (X = FSI), are chemically stable on the energized lithiated transition metal oxide electrodes, but their presence in the electrolyte causes rapid anodic dissolution and pitting of Al current collectors at potentials exceeding 4.0 V versus Li/Li +. For LiBF 4 andmore » LiPF 6, the release of HF near the energized surfaces passivates the exposed Al metal, inhibiting this pitting corrosion, but it also causes the gradual degradation of the cathode active material, negating this important advantage. Here we report that in certain electrolytes containing fluorinated carbonate solvents and LiX salts, the threshold voltage for safe operation of Al current collectors can be increased to 5.5 V versus Li/Li +. Interestingly, the most efficient solvent also facilitates the formation of an insoluble gel when AlX 3 is introduced into this solvent. We suggest that this solvent promotes the aggregation of coordination polymers of AlX 3 at the exposed Al surface that isolate this surface from the electrolyte, thereby preventing further Al dissolution and corrosion. Other examples of Al collector protection may also involve this mechanism. Our study suggests that such “allotropic control” could be a way of widening the operation window of Li-ion cells without electrode deterioration, Al current collector corrosion, and electrolyte breakdown.« less

Identification of nonvolatile coal derived products via chromatography coupled with on-line FTIR detection. Quarterly progress report, March 1-May 31, 1985. [C/sub 2/H/sub 2/ extracts of ground coal, coffee and paprika

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, L.T.

Because it has been our goal to interface the supercritical fluid chromatograph with a Fourier transform infrared spectrometer we have initially chosen packed columns due to their increased sample capacities, and supercritical CO/sub 2/ because of its infrared transparency. This paper compares two sampling techniques that can be utilized in packed column supercritical fluid Chromatography (SFC). Traditional sample introduction is accomplished using an injector with a sample loop. The loop is filled with the appropriate amount of material, and subsequently inserted into the mobile phase path. In most cases the sample must be either dissolved or extracted into an appropriatemore » solvent for such sample introduction. Note that unlike HPLC, where the solvent can be the same as the mobile phase, traditional sampling with SFC must use a solvent that is very different from the mobile phase. As a result, solvent peaks are almost always present, especially with universal detectors like FTIR. An alternative method is described here whereby both extraction of the sample and introduction of the extract onto the column is accomplished on-line using only the supercritical fluid mobile phase. This sampling technique is made possible by a simple valving scheme which ties directly the extraction vessel, the injector, the packed column and the detector. This technique has several advantages over the traditional methods, not the least of which is the absence of a large amount of foreign solvent introduced on the column. 11 refs., 7 figs.« less

Agglomeration of Celecoxib by Quasi Emulsion Solvent Diffusion Method: Effect of Stabilizer.

PubMed

Maghsoodi, Maryam; Nokhodchi, Ali

2016-12-01

Purpose: The quasi-emulsion solvent diffusion (QESD) has evolved into an effective technique to manufacture agglomerates of API crystals. Although, the proposed technique showed benefits, such as cost effectiveness, that is considerably sensitive to the choice of a stabilizer, which agonizes from a absence of systemic understanding in this field. In the present study, the combination of different solvents and stabilizers were compared to investigate any connections between the solvents and stabilizers. Methods: Agglomerates of celecoxib were prepared by QESD method using four different stabilizers (Tween 80, HPMC, PVP and SLS) and three different solvents (methyl acetate, ethyl acetate and isopropyl acetate). The solid state of obtained particles was investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The agglomerated were also evaluated in term of production yield, distribution of particles and dissolution behavior. Results: The results showed that the effectiveness of stabilizer in terms of particle size and particle size distribution is specific to each solvent candidate. A stabilizer with a lower HLB value is preferred which actually increased its effectiveness with the solvent candidates with higher lipophilicity. HPMC appeared to be the most versatile stabilizer because it showed a better stabilizing effect compared to other stabilizers in all solvents used. Conclusion: This study demonstrated that the efficiency of stabilizers in forming the celecoxib agglomerates by QESD was influenced by the HLB of the stabilizer and lipophilicity of the solvents.

Amorphous stabilization and dissolution enhancement of amorphous ternary solid dispersions: combination of polymers showing drug-polymer interaction for synergistic effects.

PubMed

Prasad, Dev; Chauhan, Harsh; Atef, Eman

2014-11-01

The purpose of this study was to understand the combined effect of two polymers showing drug-polymer interactions on amorphous stabilization and dissolution enhancement of indomethacin (IND) in amorphous ternary solid dispersions. The mechanism responsible for the enhanced stability and dissolution of IND in amorphous ternary systems was studied by exploring the miscibility and intermolecular interactions between IND and polymers through thermal and spectroscopic analysis. Eudragit E100 and PVP K90 at low concentrations (2.5%-40%, w/w) were used to prepare amorphous binary and ternary solid dispersions by solvent evaporation. Stability results showed that amorphous ternary solid dispersions have better stability compared with amorphous binary solid dispersions. The dissolution of IND from the ternary dispersion was substantially higher than the binary dispersions as well as amorphous drug. Melting point depression of physical mixtures reveals that the drug was miscible in both the polymers; however, greater miscibility was observed in ternary physical mixtures. The IR analysis confirmed intermolecular interactions between IND and individual polymers. These interactions were found to be intact in ternary systems. These results suggest that the combination of two polymers showing drug-polymer interaction offers synergistic enhancement in amorphous stability and dissolution in ternary solid dispersions. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Testing signal enhancement mechanisms in the dissolution NMR of acetone

NASA Astrophysics Data System (ADS)

Alonso-Valdesueiro, Javier; Elliott, Stuart J.; Bengs, Christian; Meier, Benno; Levitt, Malcolm H.

2018-01-01

In cryogenic dissolution NMR experiments, a substance of interest is allowed to rest in a strong magnetic field at cryogenic temperature, before dissolving the substance in a warm solvent, transferring it to a high-resolution NMR spectrometer, and observing the solution-state NMR spectrum. In some cases, negative enhancements of the 13C NMR signals are observed, which have been attributed to quantum-rotor-induced polarization. We show that in the case of acetone (propan-2-one) the negative signal enhancements of the methyl 13C sites may be understood by invoking conventional cross-relaxation within the methyl groups. The 1H nuclei acquire a relative large net polarization through thermal equilibration in a magnetic field at low temperature, facilitated by the methyl rotation which acts as a relaxation sink; after dissolution, the 1H magnetization slowly returns to thermal equilibrium at high temperature, in part by cross-relaxation processes, which induce a transient negative polarization of nearby 13C nuclei. We provide evidence for this mechanism experimentally and theoretically by saturating the 1H magnetization using a radiofrequency field pulse sequence before dissolution and comparing the 13 C magnetization evolution after dissolution with the results obtained from a conventional 1 H-13 C cross relaxation model of the CH3 moieties in acetone.

10 CFR Appendix I to Part 110 - Illustrative List of Reprocessing Plant Components Under NRC Export Licensing Authority

Code of Federal Regulations, 2014 CFR

2014-01-01

... dissolution, solvent extraction, and process liquor storage. There may also be equipment for thermal denitration of uranium nitrate, conversion of plutonium nitrate to oxide metal, and treatment of fission product waste liquor to a form suitable for long term storage or disposal. However, the specific type and...

10 CFR Appendix I to Part 110 - Illustrative List of Reprocessing Plant Components Under NRC Export Licensing Authority

Code of Federal Regulations, 2013 CFR

2013-01-01

... dissolution, solvent extraction, and process liquor storage. There may also be equipment for thermal denitration of uranium nitrate, conversion of plutonium nitrate to oxide metal, and treatment of fission product waste liquor to a form suitable for long term storage or disposal. However, the specific type and...

10 CFR Appendix I to Part 110 - Illustrative List of Reprocessing Plant Components Under NRC Export Licensing Authority

Code of Federal Regulations, 2012 CFR

2012-01-01

... dissolution, solvent extraction, and process liquor storage. There may also be equipment for thermal denitration of uranium nitrate, conversion of plutonium nitrate to oxide metal, and treatment of fission product waste liquor to a form suitable for long term storage or disposal. However, the specific type and...

Phase Behavior of Ritonavir Amorphous Solid Dispersions during Hydration and Dissolution.

PubMed

Purohit, Hitesh S; Taylor, Lynne S

2017-12-01

The aim of this research was to study the interplay of solid and solution state phase transformations during the dissolution of ritonavir (RTV) amorphous solid dispersions (ASDs). RTV ASDs with polyvinylpyrrolidone (PVP), polyvinylpyrrolidone vinyl acetate (PVPVA) and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared at 10-50% drug loading by solvent evaporation. The miscibility of RTV ASDs was studied before and after exposure to 97% relative humidity (RH). Non-sink dissolution studies were performed on fresh and moisture-exposed ASDs. RTV and polymer release were monitored using ultraviolet-visible spectroscopy. Techniques including fluorescence spectroscopy, confocal imaging, scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC) and nanoparticle tracking analysis (NTA) were utilized to monitor solid and the solution state phase transformations. All RTV-PVP and RTV-PVPVA ASDs underwent moisture-induced amorphous-amorphous phase separation (AAPS) on high RH storage whereas RTV-HPMCAS ASDs remained miscible. Non-sink dissolution of PVP- and PVPVA-based ASDs at low drug loadings led to rapid RTV and polymer release resulting in concentrations in excess of amorphous solubility, liquid-liquid phase separation (LLPS) and amorphous nanodroplet formation. High drug loading PVP- and PVPVA-based ASDs did not exhibit LLPS upon dissolution as a consequence of extensive AAPS in the hydrated ASD matrix. All RTV-HPMCAS ASDs led to LLPS upon dissolution. RTV ASD dissolution is governed by a competition between the dissolution rate and the rate of phase separation in the hydrated ASD matrix. LLPS was observed for ASDs where the drug release was polymer controlled and only ASDs that remained miscible during the initial phase of dissolution led to LLPS. Techniques such as fluorescence spectroscopy, confocal imaging and SEM were useful in understanding the phase behavior of ASDs upon hydration and dissolution and were helpful in elucidating the mechanism of generation of amorphous nanodroplets.

Evaluation of melt granulation and ultrasonic spray congealing as techniques to enhance the dissolution of praziquantel.

PubMed

Passerini, Nadia; Albertini, Beatrice; Perissutti, Beatrice; Rodriguez, Lorenzo

2006-08-02

Praziquantel (PZQ), an anthelminthic drug widely used in developing countries, is classified in Class II in the Biopharmaceutics Classification Systems; this means that PZQ has very low water solubility and high permeability, thus the dissolution is the absorption rate-limiting factor. The aim of this work was to evaluate the suitability of melt granulation and ultrasonic spray congealing as techniques for enhancing the dissolution rate of PZQ. Granules in high shear mixer were prepared by melt granulation, using polyethylene glycol 4000 or poloxamer 188 as meltable binders and alpha-lactose monohydrate as a filler. Quite regularly shaped granules having main size fraction in the range 200-500 microm were obtained using both formulations; however, only poloxamer 188 granules demonstrated a significant (P=0.05) increase of the PZQ dissolution rate compared to pure drug. To evaluate the potential of ultrasonic spray congealing, Gelucire 50/13 microparticles having different drug to carrier ratios (5, 10, 20 and 30%, w/w) were then prepared. The results showed that all the microparticles had a significant higher dissolution rate (P=0.05) respect to pure PZQ. The increase of the PZQ content considerably decreased the dissolution rate of the drug: 5 and 10% PZQ loaded systems evidenced dissolution significantly enhanced compared to 20 and 30% PZQ microparticles. The microparticle's characterisation, performed by Differential Scanning Calorimetry, Hot Stage Microscopy, X-ray powder diffraction and FT-Infrared analysis, evidenced the absence of both modifications of the solid state of PZQ and of significant interactions between the drug and the carrier. In conclusion, melt granulation and ultrasonic spray congealing could be proposed as solvent free, rapid and low expensive manufacturing methods to increase the in vitro dissolution rate of PZQ.

Improvement of the dissolution rate of artemisinin by means of supercritical fluid technology and solid dispersions.

PubMed

Van Nijlen, T; Brennan, K; Van den Mooter, G; Blaton, N; Kinget, R; Augustijns, P

2003-03-26

The purpose of this study was to enhance the dissolution rate of artemisinin in order to improve the intestinal absorption characteristics. The effect of: (1) micronisation and (2) formation of solid dispersions with PVPK25 was assessed in an in vitro dissolution system [dissolution medium: water (90%), ethanol (10%) and sodium lauryl sulphate (0.1%)]. Coulter counter analysis was used to measure particle size. X-ray diffraction and DSC were used to analyse the physical state of the powders. Micronisation by means of a jet mill and supercritical fluid technology resulted in a significant decrease in particle size as compared to untreated artemisinin. All powders appeared to be crystalline. The dissolution rate of the micronised forms improved in comparison to the untreated form, but showed no difference in comparison to mechanically ground artemisinin. Solid dispersions of artemisinin with PVPK25 as a carrier were prepared by the solvent method. Both X-ray diffraction and DSC showed that the amorphous state was reached when the amount of PVPK25 was increased to 67%. The dissolution rate of solid dispersions with at least 67% of PVPK25 was significantly improved in comparison to untreated and mechanically ground artemisinin. Modulation of the dissolution rate of artemisinin was obtained by both particle size reduction and formation of solid dispersions. The effect of particle size reduction on the dissolution rate was limited. Solid dispersions could be prepared by using a relatively small amount of PVPK25. The formation of solid dispersions with PVPK25 as a carrier appears to be a promising method to improve the intestinal absorption characteristics of artemisinin. Copyright 2003 Elsevier Science B.V.

Elucidating the Key Role of a Lewis Base Solvent in the Formation of Perovskite Films Fabricated from the Lewis Adduct Approach.

PubMed

Cao, Xiaobing; Zhi, Lili; Li, Yahui; Fang, Fei; Cui, Xian; Yao, Youwei; Ci, Lijie; Ding, Kongxian; Wei, Jinquan

2017-09-27

High-quality perovskite films can be fabricated from Lewis acid-base adducts through molecule exchange. Substantial work is needed to fully understand the formation mechanism of the perovskite films, which helps to further improve their quality. Here, we study the formation of CH 3 NH 3 PbI 3 perovskite films by introducing some dimethylacetamide into the PbI 2 /N,N-dimethylformamide solution. We reveal that there are three key processes during the formation of perovskite films through the Lewis acid-base adduct approach: molecule intercalation of solvent into the PbI 2 lattice, molecule exchange between the solvent and CH 3 NH 3 I, and dissolution-recrystallization of the perovskite grains during annealing. The Lewis base solvents play multiple functions in the above processes. The properties of the solvent, including Lewis basicity and boiling point, play key roles in forming smooth perovskite films with large grains. We also provide some rules for choosing Lewis base additives to prepare high-quality perovskite films through the Lewis adduct approach.

Photosensitive dissolution inhibitors and resists based on onium salt carboxylates

DOEpatents

Dentinger, Paul M.; Simison, Kelby L.

2005-11-29

A photoresist composition that employs onium salt carboxylates as thermally stable dissolution inhibitors. The photoresist composition can be either an onium carboxylate salt with a phenolic photoresist, such as novolac, or an onium cation protected carboxylate-containing resin such as an acrylic/acrylic acid copolymer. The onium carboxylate can be an onium cholate, wherein the onium cholate is an iodonium cholate. Particularly preferred iodonium cholates are alkyloxyphenylphenyl iodonium cholates and most particularly preferred is octyloxyphenyphenyl iodonium cholate. The photoresist composition will not create nitrogen or other gaseous byproducts upon exposure to radiation, does not require water for photoactivation, has acceptable UV radiation transmission characteristics, and is thermally stable at temperatures required for solvent removal.

Stability of the solid electrolyte Li{sub 3}OBr to common battery solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroeder, D.J.; Hubaud, A.A.; Vaughey, J.T., E-mail: vaughey@anl.gov

2014-01-01

Graphical abstract: The stability of the anti-perovskite phase Li{sub 3}OBr has been assessed in a variety of battery solvents. - Highlights: • Lithium stable solid electrolyte Li{sub 3}OBr unstable to polar organic solvents. • Solvation with no dissolution destroys long-range structure. • Ion exchange with protons observed. - Abstract: Recently a new class of solid lithium ion conductors was reported based on the anti-perovskite structure, notably Li{sub 3}OCl and Li{sub 3}OBr. For many beyond lithium-ion battery uses, the solid electrolyte is envisioned to be in direct contact with liquid electrolytes and lithium metal. In this study we evaluated the stabilitymore » of the Li{sub 3}OBr phase against common battery solvents electrolytes, including diethylcarbonate (DEC) and dimethylcarbonate (DMC), as well as a LiPF{sub 6} containing commercial electrolyte. In contact with battery-grade organic solvents, Li{sub 3}OBr was typically found to be insoluble but lost its crystallinity and reacted with available protons and in some cases with the solvent. A low temperature heat treatment was able to restore crystallinity of the samples; however evidence of proton ion exchange was conserved.« less

Study of polymorphic control in an ethanol-water binary solvent

NASA Astrophysics Data System (ADS)

Kitano, Hiroshi; Tanaka, Takayuki; Hirasawa, Izumi

2017-07-01

Three polymorphs of L-Citrulline crystals, anhydrate (Form α, γ and δ) and pseudo polymorph (dihydrate), were confirmed. In this study, polymorphic control of L-Citrulline was attempted by changing the ethanol concentration in ethanol-water binary solvents. First, each polymorph of L-Citrulline crystals was added to the prepared ethanol-water binary solvents and samples which were obtained chronologically were measured by XRD. Also, the crystal sizes and shapes in transformation were observed by microscope. Then, polymorphs of the crystals after transformation were determined by XRD pattern. As a result, the transformation from dihydrate to anhydrate was observed by adding dihydrate crystals to the ethanol-water binary solvent. Similarly, the transformation from anhydrate to another anhydrate was observed. Especially in the case of adding dihydrate, the existences of all polymorphs were confirmed by adjusting ethanol-water binary solvent. According to the results, it was revealed that polymorphic transformation was affected by the trace amount of water contained in ethanol-water binary solvent. Moreover, transformation from dihydrate to anhydrate was constructed with three phases, dissolution of dihydrate, nucleation and growth of anhydrate. Therefore, the solution-mediated polymorphic transformation was supposed to be a key mechanism for this transformation.

MOELCULAR SIZE EXCLUSION BY SOIL ORGANIC MATERIALS ESTIMATED FROM THEIR SWELLING IN ORGANIC SOLVENTS

EPA Science Inventory

A published method previously developed to measure the swelling characteristics of pow dered coal samples has been adapted for swelling measurements on various peat, pollen, chain, and cellulose samples The swelling of these macromolecular materials is the volumetric manifestatio...

MOLECULAR SIZE EXCLUSION BY SOIL ORGANIC MATERIALS ESTIMATED FROM THEIR SWELLING IN ORGANIC SOLVENTS

EPA Science Inventory

A published method previously developed to measure the swelling characteristics of powdered coal samples has been adapted for swelling measurements on various peat, pollen, chitin, and cellulose samples. he swelling of these macromolecular materials is the volumetric manifestatio...

APPLICATION OF A SPRAY DEPOSITION METHOD FOR REVERSED PHASE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

EPA Science Inventory

Four coal gasification wastewater samples were analyzed for nonvolatile and polar organics by liquid chromatography-mass spectrometry (LC/MS). Samples were separated on a reverse phase liquid chromatographic column using an aqueous solvent as the eluant. A special spray depositio...

Bench Scale Process for Low Cost CO 2 Capture Using a PhaseChanging Absorbent: Techno-Economic Analysis Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miebach, Barbara; McDuffie, Dwayne; Spiry, Irina

The objective of this project is to design and build a bench-scale process for a novel phase-changing CO 2 capture solvent. The project will establish scalability and technical and economic feasibility of using a phase-changing CO 2 capture absorbent for post-combustion capture of CO 2 from coal-fired power plants with 90% capture efficiency and 95% CO 2 purity at a cost of $40/tonne of CO 2 captured by 2025 and a cost of <$10/tonne of CO 2 captured by 2035. This report presents system and economic analysis for a process that uses a phase changing aminosilicone solvent to remove COmore » 2 from pulverized coal (PC) power plant flue gas. The aminosilicone solvent is a pure 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (GAP-0). Performance of the phase-changing aminosilicone technology is compared to that of a conventional carbon capture system using aqueous monoethanolamine (MEA). This analysis demonstrates that the aminosilicone process has significant advantages relative to an MEA-based system. The first-year CO 2 removal cost for the phase-changing CO 2 capture process is $52.1/tonne, compared to $66.4/tonne for the aqueous amine process. The phase-changing CO 2 capture process is less costly than MEA because of advantageous solvent properties that include higher working capacity, lower corrosivity, lower vapor pressure, and lower heat capacity. The phase-changing aminosilicone process has approximately 32% lower equipment capital cost compared to that of the aqueous amine process. However, this solvent is susceptible to thermal degradation at CSTR desorber operating temperatures, which could add as much as $88/tonne to the CO 2 capture cost associated with solvent makeup. Future work is focused on mitigating this critical risk by developing an advanced low-temperature desorber that can deliver comparable desorption performance and significantly reduced thermal degradation rate.« less

Low-viscosity hydroxypropylcellulose (HPC) grades SL and SSL: versatile pharmaceutical polymers for dissolution enhancement, controlled release, and pharmaceutical processing.

PubMed

Sarode, Ashish; Wang, Peng; Cote, Catherine; Worthen, David R

2013-03-01

Hydroxypropylcellulose (HPC)-SL and -SSL, low-viscosity hydroxypropylcellulose polymers, are versatile pharmaceutical excipients. The utility of HPC polymers was assessed for both dissolution enhancement and sustained release of pharmaceutical drugs using various processing techniques. The BCS class II drugs carbamazepine (CBZ), hydrochlorthiazide, and phenytoin (PHT) were hot melt mixed (HMM) with various polymers. PHT formulations produced by solvent evaporation (SE) and ball milling (BM) were prepared using HPC-SSL. HMM formulations of BCS class I chlorpheniramine maleate (CPM) were prepared using HPC-SL and -SSL. These solid dispersions (SDs) manufactured using different processes were evaluated for amorphous transformation and dissolution characteristics. Drug degradation because of HMM processing was also assessed. Amorphous conversion using HMM could be achieved only for relatively low-melting CBZ and CPM. SE and BM did not produce amorphous SDs of PHT using HPC-SSL. Chemical stability of all the drugs was maintained using HPC during the HMM process. Dissolution enhancement was observed in HPC-based HMMs and compared well to other polymers. The dissolution enhancement of PHT was in the order of SE>BM>HMM>physical mixtures, as compared to the pure drug, perhaps due to more intimate mixing that occurred during SE and BM than in HMM. Dissolution of CPM could be significantly sustained in simulated gastric and intestinal fluids using HPC polymers. These studies revealed that low-viscosity HPC-SL and -SSL can be employed to produce chemically stable SDs of poorly as well as highly water-soluble drugs using various pharmaceutical processes in order to control drug dissolution.

Natural radionuclides in plants, soils and sediments affected by U-rich coal mining activities in Brazil.

PubMed

Galhardi, Juliana Aparecida; García-Tenorio, Rafael; Bonotto, Daniel Marcos; Díaz Francés, Inmaculada; Motta, João Gabriel

2017-10-01

Mining activities can increase the mobility of metals by accelerating the dissolution and leaching of minerals from the rocks and tailing piles to the environment and, consequently, their availability for plants and subsequent transfer to the food chain. The weathering of minerals and the disposal of coal waste in tailing piles can accelerate the generation of acid mine drainage (AMD), which is responsible for the higher dissolution of metals in mining areas. In this context, the behavior of U, Th and K in soils and sediment, and the transfer factor (TF) of 238 U, 234 U and 210 Po for soybean, wheat, pine and eucalyptus cultivated around a coal mine in southern Brazil was evaluated. Alpha and gamma spectrometry were used for the measurements of the activity concentration of the radioelements. 210 Po was the radionuclide that is most accumulated in the plants, especially in the leaves. When comparing the plant species, pine showed the highest TF values for 234 U (0.311 ± 0.420) for leaves, while eucalyptus showed the highest TF for 238 U (0.344 ± 0.414) for leaves. In general, TF were higher for the leaves of soybean and wheat when compared to the grains, and grains of wheat showed higher TF for 210 Po and 238 U than grains of soybean. Deviations from the natural U isotopic ratio were recorded at all investigated areas, indicating possible industrial and mining sources of U for the vegetables. A safety assessment of transport routes and accumulation of radionuclides in soils with a potential for cultivation is important, mainly in tropical areas contaminated with solid waste and effluents from mines and industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental characterisation of coal mine waste rock in the field: an example from New Zealand

NASA Astrophysics Data System (ADS)

Hughes, J.; Craw, D.; Peake, B.; Lindsay, P.; Weber, P.

2007-08-01

Characterisation of mine waste rock with respect to acid generation potential is a necessary part of routine mine operations, so that environmentally benign waste rock stacks can be constructed for permanent storage. Standard static characterisation techniques, such as acid neutralisation capacity (ANC), maximum potential acidity, and associated acid-base accounting, require laboratory tests that can be difficult to obtain rapidly at remote mine sites. We show that a combination of paste pH and a simple portable carbonate dissolution test, both techniques that can be done in the field in a 15 min time-frame, is useful for distinguishing rocks that are potentially acid-forming from those that are acid-neutralising. Use of these techniques could allow characterisation of mine wastes at the metre scale during mine excavation operations. Our application of these techniques to pyrite-bearing (total S = 1-4 wt%) but variably calcareous coal mine overburden shows that there is a strong correlation between the portable carbonate dissolution technique and laboratory-determined ANC measurements (range of 0-10 wt% calcite equivalent). Paste pH measurements on the same rocks are bimodal, with high-sulphur, low-calcite rocks yielding pH near 3 after 10 min, whereas high-ANC rocks yield paste pH of 7-8. In our coal mine example, the field tests were most effective when used in conjunction with stratigraphy. However, the same field tests have potential for routine use in any mine in which distinction of acid-generating rocks from acid-neutralising rocks is required. Calibration of field-based acid-base accounting characteristics of the rocks with laboratory-based static and/or kinetic tests is still necessary.

Long-term ground penetrating radar monitoring of a small volume DNAPL release in a natural groundwater flow field.

PubMed

Hwang, Yong Keun; Endres, Anthony L; Piggott, Scott D; Parker, Beth L

2008-04-04

An earlier field experiment at Canadian Forces Base Borden by Brewster and Annan [Geophysics 59 (1994) 1211] clearly demonstrated the capability of ground penetrating radar (GPR) reflection profiling to detect and monitor the formation of DNAPL layers in the subsurface. Their experiment involved a large volume release (770 L) of tetrachloroethylene into a portion of the sand aquifer that was hydraulically isolated from groundwater flow by sheet pile walls. In this study, we evaluated the ability of GPR profiling to detect and monitor much smaller volume releases (50 L). No subsurface confining structure was used in this experiment; hence, the DNAPL impacted zone was subjected to the natural groundwater flow regime. This condition allowed us to geophysically monitor the DNAPL mass loss over a 66 month period. Reflectivity variations on the GPR profiles were used to infer the presence and evolution of the solvent layers. GPR imaging found significant reflectivity increases due to solvent layer formation during the two week period immediately after the release. These results demonstrated the capacity of GPR profiling for the detection and monitoring of lesser volume DNAPL releases that are more representative of small-scale industrial spills. The GPR imaged solvent layers subsequently reduced in both areal extent and reflectivity after 29 months and almost completely disappeared by the end of the 66 month monitoring period. Total DNAPL mass estimates based on GPR profiling data indicated that the solvent mass was reduced to 34%-36% of its maximum value after 29 months; only 4%-9% of the solvent mass remained in the study area after 66 months. These results are consistent with independent hydrogeological estimates of remaining DNAPL mass based on the downgradient monitoring of the dissolved solvent phase. Hence, we have concluded that the long-term GPR reflectivity changes of the DNAPL layers are likely the result from the dissolution of chlorinated solvents residing in those layers. The long-term monitoring results demonstrated that GPR profiling is a promising non-invasive method for use at DNAPL contaminated sites in sandy aquifers where temporal information about immiscible contaminant mass depletion due to either natural flow or remediation is needed. However, our results also indicated that the GPR signature of older DNAPL impacted zones may not differ greatly from the uncontaminated background if significant mass reduction due to dissolution has occurred.

Arsenic-bearing pyrite and marcasite in the Fire Clay coal bed, Middle Pennsylvanian Breathitt Formation, eastern Kentucky

USGS Publications Warehouse

Ruppert, L.F.; Hower, J.C.; Eble, C.F.

2005-01-01

Arsenic concentrations determined on 11 lithotype samples from the Middle Pennsylvanian Breathitt Group Fire Clay coal bed, Leslie County, KY, range from 1 to 418 ppm (whole coal basis). The 11 lithotype samples, which vary in thickness from 4 to 18 cm, were sampled from a continuous 1.38 m channel sample, and were selected based on megascopic appearance (vitrain-rich versus attrital-rich). A lithotype that contains 418 ppm As is located near the top of the coal bed and is composed of 10.5 cm of bright clarain bands containing fusain that, within short distances, grade laterally into Fe sulfide bands. To determine the mode of occurrence of As in this lithotype, the coal was examined with scanning electron microscopy and analyzed by energy dispersive X-ray fluorescence. Massive, framboidal, cell filling, cell-wall replacement, and radiating forms of Fe sulfide were observed in the high As lithotype; many of the radiating Fe sulfide forms, and one of the cell-wall replacements contained As. Examination of the grains with optical light microscopy shows that the majority of radiating morphologies are pyrite, the remainder are marcasite. Selected Fe sulfide grains were also analyzed by electron microprobe microscopy. Arsenic concentrations within individual grains range from 0.0 wt.% to approximately 3.5 wt.%. On the basis of morphology, these Fe sulfides are presumed to be of syngenetic origin and would probably be removed from the coal during physical coal cleaning, thus eliminating a potential source of As from the coal combustion process. However, because the grains are radiating and have high surface area, dissolution and release of As could occur if the pyrite is oxidized in refuse ponds.

Self-assembly of resins and asphaltenes facilitates asphaltene dissolution by an organic acid.

PubMed

Hashmi, Sara M; Firoozabadi, Abbas

2013-03-15

Asphaltene precipitation occurs in petroleum fluids under certain unfavorable conditions, but can be controlled by tuning composition. Aromatic solvents in large quantities can prevent precipitation entirely and can dissolve already precipitated asphaltenes. Some polymeric surfactants can dissolve asphaltenes when added at much lower concentrations than required by aromatic solvents. Other dispersants can truncate asphaltene precipitation at the sub-micron length scale, creating stable colloidal asphaltene dispersants. One particular asphaltene dispersant, dodecylbenzene sulfonic acid (DBSA), can do both, namely: (1) stabilize asphaltene colloids and (2) dissolve asphaltenes to the molecular scale. Acid-base interactions are responsible for the efficiency of DBSA in dissolving asphaltenes compared to aromatic solvents. However, many details remain to be quantified regarding the action of DBSA on asphaltenes, including the effect of petroleum fluid composition. For instance, resins, naturally amphiphilic components of petroleum fluids, can associate with asphaltenes, but it is unknown whether they cooperate or compete with DBSA. Similarly, the presence of metals is known to hinder asphaltene dissolution by DBSA, but its effect on colloidal asphaltene stabilization has yet to be considered. We introduce the concepts of cooperativity and competition between petroleum fluid components and DBSA in stabilizing and dissolving asphaltenes. Notably, we find that resins cooperatively interact with DBSA in dissolving asphaltenes. We use UV-vis spectroscopy to investigate the interactions responsible for the phase transitions between unstable suspensions, stable suspensions, and molecular solutions of asphaltenes. Copyright © 2012 Elsevier Inc. All rights reserved.

Enthalpy measurement of coal-derived liquids. Technical progress report, November 1982-January 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kidnay, A.J.; Yesavage, V.F.

The objective of this research is to measure the enthalpy for representative coal-derived liquids and model compounds over the pressure and temperature regions most likely to be encountered in both liquefaction and processing systems, and to prepare from the data an enthalpy correlation suitable for process design calculations. The correlational effort this past quarter on the enthalpy of coal-derived syncrudes and model compounds has emphasized the experimental determination of a correlating factor for association in coal liquids. As in previous work, the degree of association is to be related to cryoscopic molecular weight determinations on the coal liquids. To thismore » end, work on and an evaluationof a cryoscopic molecular weight apparatus was completed this quarter. Molecular weights of coal liquids determined by the standard Beckman freezing point depression apparatus were consistently low (5 to 10%). After modifications of the apparatus, it was tested with the following compounds: hexane, dodecane, m-xylene and naphthalene. Benzene was the solvent used. However, the molecular weight measurements were again consistently lower than the true values, and in many cases the experimental error was greater than that of the Beckman apparatus.« less

Synfuels and the energy transition

NASA Astrophysics Data System (ADS)

Balzhiser, R. E.

1981-08-01

Various synfuel options and their impact on the electric utility industry are discussed. The energy transition for the U.S.A. is seen as moving from natural fluid fuels to solid fuels and renewable energy resources. The key to this transition is electrification, which can encompass both nuclear and renewable resources, centralized and dispersed technologies. It is shown that the fraction of total energy converted to electricity has risen steadily for the past 30 years, reaching 33% last year. The abundance and cost of production of the various fossil energy resources, including natural gas, heavy oil, oil shale, and coal are considered. EPRI analyses indicate that an integrated-combined-cycle power plant could be competitive with conventional coal plant technology. These plants would use only half the water of current coal-fired plants, would meet tighter sulfur emission standards, and would produce a vitreous ash that is less leachable than the ash from today's coal plants. Solvent-refined coal processes, currently being developed in the U.S.A. are a second approach to converting coal to liquid fuels. It is pointed out, however, that synfuels will complement, not replace, other sources of energy in the continued electrification of the U.S.A.

Superacid Catalyzed Coal Conversion Chemistry. 1st and 2nd Quarterly Technical Progress Reports, September 1, 1983-March 30, 1984.

DOE R&D Accomplishments Database

Olah, G. A.

1984-01-01

In our laboratories we have previously developed a mild coal conversion process. This involves the use of a superacid system consisting of HF and BF{sub 3} in presence of hydrogen and/or a hydrogen donor solvent. In order to understand the chemistry involved in the process of depolymerization of coal by the HF:BF{sub 3}:H{sub 2} system we are carrying out a systematic study of a number of coal model compounds. The model compounds selected for present study have two benzene rings connected with various bridging units such as alkylidene, ether, sulfide etc. From studies so far carried out it appears that high pyridine extractibilities achieved by treating coal at temperature below 100 degrees C results from the cleavage of bridges such as present in bibenzyl, diphenyl methane, dibenzyl ether, dibenzyl sulfide etc. On the other hand the increased cyclohexane extractibility and distillability observed at relatively higher temperatures and hydrogen pressures reflects the hydrogenation and cleavage of the aromatic backbone in coal structure similar to what is seen in the conversion of model compounds such as biphenyl, diphenyl ether, diphenyl sulfide, anthracene, etc.

Extraction of Trivalent Actinides and Lanthanides from Californium Campaign Rework Solution Using TODGA-based Solvent Extraction System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benker, Dennis; Delmau, Laetitia Helene; Dryman, Joshua Cory

This report presents the studies carried out to demonstrate the possibility of quantitatively extracting trivalent actinides and lanthanides from highly acidic solutions using a neutral ligand-based solvent extraction system. These studies stemmed from the perceived advantage of such systems over cationexchange- based solvent extraction systems that require an extensive feed adjustment to make a low-acid feed. The targeted feed solutions are highly acidic aqueous phases obtained after the dissolution of curium targets during a californium (Cf) campaign. Results obtained with actual Cf campaign solutions, but highly diluted to be manageable in a glove box, are presented, followed by results ofmore » tests run in the hot cells with Cf campaign rework solutions. It was demonstrated that a solvent extraction system based on the tetraoctyl diglycolamide molecule is capable of quantitatively extracting trivalent actinides from highly acidic solutions. This system was validated using actual feeds from a Cf campaign.« less

Catalytic two-stage coal hydrogenation and hydroconversion process

DOEpatents

MacArthur, James B.; McLean, Joseph B.; Comolli, Alfred G.

1989-01-01

A process for two-stage catalytic hydrogenation and liquefaction of coal to produce increased yields of low-boiling hydrocarbon liquid and gas products. In the process, the particulate coal is slurried with a process-derived liquid solvent and fed at temperature below about 650.degree. F. into a first stage catalytic reaction zone operated at conditions which promote controlled rate liquefaction of the coal, while simultaneously hydrogenating the hydrocarbon recycle oils at conditions favoring hydrogenation reactions. The first stage reactor is maintained at 650.degree.-800.degree. F. temperature, 1000-4000 psig hydrogen partial pressure, and 10-60 lb coal/hr/ft.sup.3 reactor space velocity. The partially hydrogenated material from the first stage reaction zone is passed directly to the close-coupled second stage catalytic reaction zone maintained at a temperature at least about 25.degree. F. higher than for the first stage reactor and within a range of 750.degree.-875.degree. F. temperature for further hydrogenation and thermal hydroconversion reactions. By this process, the coal feed is successively catalytically hydrogenated and hydroconverted at selected conditions, which results in significantly increased yields of desirable low-boiling hydrocarbon liquid products and minimal production of undesirable residuum and unconverted coal and hydrocarbon gases, with use of less energy to obtain the low molecular weight products, while catalyst life is substantially increased.

Naproxen Microparticulate Systems Prepared Using In Situ Crystallisation and Freeze-Drying Techniques.

PubMed

Solaiman, Amanda; Tatari, Adam Keenan; Elkordy, Amal Ali

2017-07-01

Poor drug solubility and dissolution rate remain to be one of the major problems facing pharmaceutical scientists, with approximately 40% of drugs in the industry categorised as practically insoluble or poorly water soluble. This in turn can lead to serious delivery challenges and poor bioavailability. The aim of this research was to investigate the effects of the surfactants, poloxamer 407 (P407) and caprol® PGE 860 (CAP), at various concentrations (0.1, 0.5, 1 and 3% w/v) on the enhancement of the dissolution properties of poorly water-soluble drug, naproxen, using in situ micronisation by solvent change method and freeze-drying. The extent at which freeze-drying influences the dissolution rate of naproxen microcrystals is investigated in this study by comparison with desiccant-drying. All formulations were evaluated and characterised using particle size analysis and morphology, in vitro dissolution studies, differential scanning calorimetry (DSC), and Fourier transform infra-red (FT-IR) spectroscopy. An increase in poloxamer 407 concentration in freeze-dried formulations led to enhancement of drug dissolution compared to desiccator-dried formulations, naproxen/caprol® PGE 860 formulations and untreated drug. DSC and FT-IR results show no significant chemical interactions between drug and poloxamer 407, with only very small changes to drug crystallinity. On the other hand, caprol® PGE 860 showed some interactions with drug components, alterations to the crystal lattice of naproxen, and poor dissolution profiles using both drying methods, making it a poor choice of excipient.

Microfibrous Solid Dispersions of Poorly Water-Soluble Drugs Produced via Centrifugal Spinning: Unexpected Dissolution Behavior on Recrystallization.

PubMed

Marano, Stefania; Barker, Susan A; Raimi-Abraham, Bahijja T; Missaghi, Shahrzad; Rajabi-Siahboomi, Ali; Aliev, Abil E; Craig, Duncan Q M

2017-05-01

Temperature-controlled, solvent-free centrifugal spinning may be used as a means of rapid production of amorphous solid dispersions in the form of drug-loaded sucrose microfibers. However, due to the high content of amorphous sucrose in the formulations, such microfibers may be highly hygroscopic and unstable on storage. In this study, we explore both the effects of water uptake of the microfibers and the consequences of deliberate recrystallization for the associated dissolution profiles. The stability of sucrose microfibers loaded with three selected BCS class II model drugs (itraconazole (ITZ), olanzapine (OLZ), and piroxicam (PRX)) was investigated under four different relative humidity conditions (11, 33, 53, and 75% RH) at 25 °C for 8 months, particularly focusing on the effect of the highest level of moisture (75% RH) on the morphology, size, drug distribution, physical state, and dissolution performance of microfibers. While all samples were stable at 11% RH, at 33% RH the ITZ-sucrose system showed greater resistance against devitrification compared to the OLZ- and PRX-sucrose systems. For all three samples, the freshly prepared microfibers showed enhanced dissolution and supersaturation compared to the drug alone and physical mixes; surprisingly, the dissolution advantage was largely maintained or even enhanced (in the case of ITZ) following the moisture-induced recrystallization under 75% RH. Therefore, this study suggests that the moisture-induced recrystallization process may result in considerable dissolution enhancement compared to the drug alone, while overcoming the physical stability risks associated with the amorphous state.

Development of paracetamol-caffeine co-crystals to improve compressional, formulation and in vivo performance.

PubMed

Latif, Sumera; Abbas, Nasir; Hussain, Amjad; Arshad, Muhammad Sohail; Bukhari, Nadeem Irfan; Afzal, Hafsa; Riffat, Sualeha; Ahmad, Zeeshan

2018-07-01

Paracetamol, a frequently used antipyretic and analgesic drug, has poor compression moldability owing to its low plasticity. In this study, new co-crystals of paracetamol (PCM) with caffeine (as a co-former) were prepared and delineated. Co-crystals exhibited improved compaction and mechanical behavior. A screening study was performed by utilizing a number of methods namely dry grinding, liquid assisted grinding (LAG), solvent evaporation (SE), and anti-solvent addition using various weight ratios of starting materials. LAG and SE were found successful in the screening study. Powders at 1:1 and 2:1 weight ratio of PCM/CAF by LAG and SE, respectively, resulted in the formation of co-crystals. Samples were characterized by PXRD, DSC, and ATR-FTIR techniques. Compressional properties of PCM and developed co-crystals were analyzed by in-die heckle model. Mean yield pressure (Py), an inverse measure of plasticity, obtained from the heckle plots decreased significantly (p < .05) for co-crystals than pure drug. Intrinsic dissolution profile of co-crystals showed up to 2.84-fold faster dissolution than PCM and physical mixtures in phosphate buffer pH 6.8 at 37 °C. In addition, co-crystals formulated into tablets by direct compression method showed better mechanical properties like hardness and tensile strength. In vitro dissolution studies on tablets also showed enhanced dissolution profiles (∼90-97%) in comparison to the tablets of PCM prepared by direct compression (∼55%) and wet granulation (∼85%) methods. In a single dose sheep model study, co-crystals showed up to twofold increase in AUC and C max . A significant (p < .05) decrease in clearance as compared to pure drug was also recorded. In conclusion, new co-crystals of PCM were successfully prepared with improved tabletability in vitro and in vivo profile. Enhancement in AUC and C max of PCM by co-crystallization might suggest the dose reduction and avoidance of side effects.

Investigation of nanosized crystalline form to improve the oral bioavailability of poorly water soluble cilostazol.

PubMed

Miao, Xiaoqing; Sun, Changshan; Jiang, Tongying; Zheng, Li; Wang, Tianyi; Wang, Siling

2011-01-01

The aim of this study was to develop cilostazol (CLT) nanocrystals intended to improve its dissolution rate and enhance its bioavailability. In this study, CLT nanosuspension was prepared by the anti-solvent and high-pressure homogenization method. The effects of the production parameters, such as the stabilizer concentration, pressure and number of cycles, were investigated. Characterization of the product was performed by scanning electron microscopy (SEM), Nitrogen adsorption, differential scanning calorimetry (DSC), X-ray powder diffraction analysis (XRPD), X-ray Photoelectron Spectroscopy (XPS), particle size analysis and dissolution testing. Additionally, the comparison studies of oral bioavailability in beagle dogs of three type tables were performed. The images of SEM showed a spherical smooth CLT powder, and Nitrogen adsorption test revealed spray dried powder were porous with high BET surface area compared with that of raw CLT. DSC and XRPD results demonstrated that the combination of preferred polymorph B and C of CLT were prepared successfully, the saturation solubility of the nanosized crystalline powder is about 5 fold greater than that of raw CLT, and the dissolution rate was enhanced 4 fold than that of raw CLT. The Cmax and AUC0-48h of CLT nanosized crystalline tablets were 2.1 fold and 1.9 fold, and 3.0 fold and 2.3 fold compared with those of the nanosized tablets and commercial tablets, respectively. The anti-solvent-high-pressure homogenization technique was employed successfully to produce cilostazol nanosuspensions. The bioavailability of CLT tablets prepared using spray dried nanosized crystalline powder after oral administration to dogs was markedly increased compared with that produced by nanosized tablets and commercial tablets, because of its greater dissolution rate owing to its transition of the crystalline state to form C and form B, reduced particle size and porous structure with increased surface area.

Anaerobic microbial dissolution of lead and production of organic acids

DOEpatents

Francis, A.J.; Dodge, C.; Chendrayan, K.; Quinby, H.L.

1987-04-16

The present invention related to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rat of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 ..mu..moles of lead as lead oxide was 0.042 ..mu..moles m1/sup /-/1/ hr/sup /-/1/. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of the strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids. 4 figs., 3 tabs.

Geochemical characteristics of dissolved rare earth elements in acid mine drainage from abandoned high-As coal mining area, southwestern China.

PubMed

Li, Xuexian; Wu, Pan

2017-09-01

Acid mine drainage (AMD) represents a major source of water pollution in the small watershed of Xingren coalfield in southwestern Guizhou Province. A detailed geochemical study was performed to investigate the origin, distribution, and migration of REEs by determining the concentrations of REEs and major solutes in AMD samples, concentrations of REEs in coal, bedrocks, and sediment samples, and modeling REEs aqueous species. The results highlighted that all water samples collected in the mining area are identified as low pH, high concentrations of Fe, Al, SO 4 2- and distinctive As and REEs. The spatial distributions of REEs showed a peak in where it is nearby the location of discharging of AMD, and then decrease significantly with distance away from the mining areas. Lots of labile REEs have an origin of coal and bedrocks, whereas the acid produced by the oxidation of pyrite is a prerequisite to cause the dissolution of coal and bedrocks, and then promoting REEs release in AMD. The North American Shale Composite (NASC)-normalized REE patterns of coal and bedrocks are enriched in light REEs (LREEs) and middle REEs (MREEs) relative to heavy REEs (HREEs). Contrary to these solid samples, AMD samples showed slightly enrichment of MREEs compared with LREEs and HREEs. This behavior implied that REEs probably fractionate during acid leaching, dissolution of bedrocks, and subsequent transport, so that the MREEs is primarily enriched in AMD samples. Calculation of REEs inorganic species for AMD demonstrated that sulfate complexes (Ln(SO 4 ) + and Ln(SO 4 ) 2 - ) predominate in these species, accounting for most of proportions for the total REEs species. The high concentrations of dissolved SO 4 2- and low pH play a decisive role in controlling the presence of REEs in AMD, as these conditions are necessary for formation of stable REEs-sulfate complexes in current study. The migration and transportation of REEs in AMD are more likely constrained by adsorption and co-precipitation of Fe-Al hydroxides/hydroxysulfate. In addition, the MREEs is preferentially captured by poorly crystalline Fe-Al hydroxides/hydroxysulfate, which favors that sediments also preserve NASC-normalized patterns with MREEs enrichment in the stream.

Liquefaction of black thunder coal with counterflow reactor technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, R.J.; Simpson, P.L.

There is currently a resurgence of interest in the use of carbon monoxide and water to promote the solubilization of low rank coals in liquefaction processes. The mechanism for the water shift gas reaction (WGSR) is well documented and proceeds via a formate ion intermediate at temperatures up to about 400{degrees}C. Coal solubilization is enhanced by CO/H{sub 2}O and by the solvent effect of the supercritical water. The WGSR is catalyzed by bases (alkali metal carbonates, hydroxides, acetates, aluminates). Many inorganic salts which promote catalytic hydrogenation are rendered inactive in CO/H{sub 2}O, although there is positive evidence for the benefitmore » of using pyrite for both the WGSR and as a hydrogenation catalyst. The temperatures at which coal solubilization occurs are insufficient to promote extensive cracking or upgrading of the solubilized coal. Therefore, a two step process might achieve these two reactions sequentially. Alberta Research Council (ARC) has developed a two-stage process for the coprocessing of low rank coals and petroleum resids/bitumens. This process was further advanced by utilizing the counterflow reactor (CFR) concept pioneered by Canadian Energy Developments (CED) and ARC. The technology is currently being applied to coal liquefaction. The two-stage process employs CO/H{sub 2}O at relatively mid temperature and pressure to solubilize the coal, followed by a more severe hydrocracking step. This paper describes the results of an autoclave study conducted to support a bench unit program on the direct liquefaction of coals.« less

A characterization and evaluation of coal liquefaction process streams. Quarterly technical progress report, October 1--December 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robbins, G.A.; Brandes, S.D.; Winschel, R.A.

1995-05-01

The objectives of this project are to support the DOE direct coal liquefaction process development program and to improve the useful application of analytical chemistry to direct coal liquefaction process development. Independent analyses by well-established methods will be obtained of samples produced in direct coal liquefaction processes under evaluation by DOE. Additionally, analytical instruments and techniques which are currently underutilized for the purpose of examining coal-derived samples will be evaluated. The data obtained from this study will be used to help guide current process development and to develop an improved data base on coal and coal liquids properties. A samplemore » bank will be established and maintained for use in this project and will be available for use by other researchers. The reactivity of the non-distillable resids toward hydrocracking at liquefaction conditions (i.e., resid reactivity) will be examined. From the literature and data experimentally obtained, a mathematical kinetic model of resid conversion will be constructed. It is anticipated that such a model will provide insights useful for improving process performance and thus the economics of direct coal liquefaction. During this quarter, analyses were completed on 65 process samples from representative periods of HRI Run POC-2 in which coal, coal/plastics, and coal/rubber were the feedstocks. A sample of the oil phase of the oil/water separator from HRI Run POC-1 was analyzed to determine the types and concentrations of phenolic compounds. Chemical analyses and microautoclave tests were performed to monitor the oxidation and measure the reactivity of the standard coal (Old Ben Mine No. 1) which has been used for the last six years to determine solvent quality of process oils analyzed in this and previous DOE contracts.« less

In vitro study comparing the ability of mono-octanoin and mono-octanoin plus methyl tert-butyl ether to dissolve biliary stones.

PubMed

Tritapepe, R; Cesana, B

1996-01-01

This in vitro study compared the gallstone dissolution rates of mono-octanoin, mono-octanoin plus 10% distilled water, and mono-octanoin plus methyl tert-butyl ether 2:1. Sixteen stones were treated with each solvent at a slow perfusion rate of 3-4 ml/h and a rapid perfusion rate of 2.5 ml/30 min with 20-sec instillation/aspiration cycles, both with and without bile. The stones were weighed before, and 3, 6, 12 and 24 hrs after the start of treatment: the solvent was changed every 30 min. After 24 hrs of instillation/aspiration without bile, the mono-octanoin/methyl tert-butyl ether mixture reduced the weight of the stones by 93%, mono-octanoin plus water by 63%, and mono-octanoin alone by 52%; with bile, the figures were, respectively, 86%, 42% and 40%. The mono-octanoin/methyl tert-butyl ether mixture thus took approximately half the time needed by the other two preparations to dissolve the stones to the same extent, a finding which may be relevant for the clinical dissolution of bile duct stones.

Liquid permeation and chemical stability of anodic alumina membranes

PubMed Central

Buldakov, Dmitrii A; Tishkin, Alexey A; Lukashin, Alexey V; Eliseev, Andrei A

2017-01-01

A study on the chemical stability of anodic alumina membranes and their performance in long-term water and organic solvent permeation experiments is reported. Anodic alumina possesses high stability for both protonic and aprotonic organic solvents. However, serious degradation of the membrane occurs in pure water, leading to a drastic decrease of permeance (over 20% of the initial value after the passing of 0.250 m3/m2 of pure water). The drying of the membrane induces further permeance drop-off. The rate of membrane degradation strongly depends on the pH of the penetrant solution and increases in basic media. According to 27Al NMR and thermogravimetry results, the degradation of the membranes is associated with the dissolution of water-soluble [Al13O4(OH)24(H2O)12]7+ polyhydroxocomplexes and their further redeposition in the form of [Al(OH)4]−, resulting in channels blocking. This process intensifies in basic pH due to the high positive charge of the anodic alumina surface. An approach for improving anodic aluminum oxide stability towards dissolution in water by carbon CVD coating of the membrane walls is suggested. PMID:28382245

Thermally-prepared polymorphic forms of cilostazol.

PubMed

Stowell, Grayson W; Behme, Robert J; Denton, Stacy M; Pfeiffer, Inigo; Sancilio, Frederick D; Whittall, Linda B; Whittle, Robert R

2002-12-01

Prior to this study, cilostazol, an antithrombotic drug, was thought to exist as a single crystalline phase with a melting point of approximately 159 degrees C (Form A). On cooling, melts often form a glass that, when heated, may crystallize as additional crystalline polymorphic forms. Cilostazol, when reheated, subsequently forms polymorphs that melt at approximately 136 degrees C (Form B) and 146 degrees C (Form C). Free-energy temperature diagrams estimated from calorimetry data reveal that each pair of the cilostazol polymorphs (A-B, B-C, and A-C) is monotropic. Essentially pure samples of suitable crystalline shape and size permitted single crystal structural analysis of Forms A and C. Theoretical solubility ratios calculated using calorimetry data indicate that at 37 degrees C, Form B should be more than four times more soluble and Form C should be more than two times more soluble than Form A. Forms B and C could not be crystallized from solvents. Metastable forms from super cooled melts analyzed by intrinsic dissolution and Fourier transform-Raman experiments demonstrated that Forms B and C undergo a rapid, solvent-mediated recrystallization to Form A, making dissolution rate measurements difficult. Copyright 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:2481-2488, 2002

Enzymatic desulfurization of coal: Third quarterly report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marquis, Judith K.; Kitchell, Judith P.

Our current efforts to develop clean coal technology emphasize the advantages of enzymatic desulfurization techniques and have specifically addressed the potential of using partially-purified extracellular microbial enzymes or commercially available enzymes. Our work is focused on the treatment of ''model'' organic sulfur compounds such as dibenzothiophene (DBT) and ethylphenylsulfide (EPS). Furthermore, we are designing experiments to facilitate the enzymatic process by means of a hydrated organic solvent matrix. In this quarter we obtained important results both with the development of our understanding of the enzyme reaction systems and also with the microbial work at Woods Hole. 12 figs., 11 tabs.

Assessment of hupu gum for its carrier property in the design and evaluation of solid mixtures of poorly water soluble drug - rofecoxib.

PubMed

Vadlamudi, Harini Chowdary; Raju, Y Prasanna; Asuntha, G; Nair, Rahul; Murthy, K V Ramana; Vulava, Jayasri

2014-01-01

There are no reports about the pharmaceutical applications of hupu gum (HG). Hence the present study was undertaken to test its suitability in the dissolution enhancement of poorly water soluble drug. Rofecoxib (RFB) was taken as model drug. For comparison solid mixtures were prepared with carriers such as poly vinyl pyrrolidone (PVP), sodium starch glycollate (SSG) and guar gum (GG). Physical mixing (PM), co-grinding (CG), kneading (KT) and solvent evaporation (SE) techniques were used to prepare the solid mixtures, using all the carriers in different carrier and drug ratios. The solid mixtures were characterized by powder X-ray diffraction (XRD) and Fourier-transformed infrared spectroscopy (FTIR). There was a significant improvement in the dissolution rate of solid mixtures of HG, when compared with the solid mixtures of other carriers. There was an increase in dissolution rate with increase in concentration of HG upto 1:1 ratio of carrier and drug. No drug-carrier interaction was found by FTIR studies. XRD studies indicated reduction in crystallinity of the drug with increase in HG concentration. Hence HG could be a useful carrier for the dissolution enhancement of poorly water soluble drugs.

Dissolution of Lignocelluloses with a High Lignin Content in a N-Methylmorpholine-N-oxide Monohydrate Solvent System via Simple Glycerol-Swelling and Mechanical Pretreatments.

PubMed

Zhang, Lili; Lu, Hailong; Yu, Juan; Wang, Zhiguo; Fan, Yimin; Zhou, Xiaofan

2017-11-08

Lignocelluloses (LCs) with various amounts of lignin (even as high as 18.4%) were successfully dissolved in N-methylmorpholine-N-oxide monohydrate (NMMO/H 2 O) solution with stirring at 85 °C within 5 h. For the developmental dissolution methods of LCs with a high lignin content in NMMO/H 2 O solution, the following two pretreatment steps of LCs were necessary: (1) glycerol swelling and (2) mechanical extrusion. The mechanical extrusion pretreatment under glycerol swelling dissociated the fiber bundles of LCs to thinner fibers and, thus, enhanced the accessibility and solubility of the LCs in NMMO/H 2 O. The crystal structure of the pretreated LCs had no significant transformation during pretreatment, while the diameters of the fiber bundles were reduced from 50-60 to 10-12 μm, as investigated by X-ray diffraction and scanning electron microscopy. After the dissolution-regeneration process of LCs, the fiber bundles of the LCs disappeared and the crystal type of cellulose in the LCs was transformed from cellulose I to cellulose II, which indicated the complete dissolution of LCs.

In-vitro dissolution rate and molecular docking studies of cabergoline drug with β-cyclodextrin

NASA Astrophysics Data System (ADS)

Shanmuga priya, Arumugam; Balakrishnan, Suganya bharathi; Veerakanellore, Giri Babu; Stalin, Thambusamy

2018-05-01

The physicochemical properties and dissolution profile of cabergoline drug (CAB) with β-cyclodextrin (β-CD) inclusion complex were investigated by the UV spectroscopy. The inclusion complex has used to calculate the stability constant and gives the stoichiometry molar ratio is 1:1 between CAB and β-CD. The phase solubility diagram and the aqueous solubility of CAB (60%) was found to be enhanced by β-CD. In addition, the phase solubility profile of CAB with β-CD was classified as AL-type. Binary systems of CAB with β-CD were prepared by Physical mixture, Kneading and solvent evaporation methods. The solid-state properties of the inclusion complex were characterized by Fourier transformation-infrared spectroscopy, Differential scanning calorimetry, Powder X-ray diffractometric patterns and Scanning electron microscopic techniques. Theoretically, β-CD and CAB inclusion complex obtained by molecular docking studies, it is in good correlation with the results obtained through experimental methods using the Schrödinger software program. In-vitro dissolution profiles of the inclusion complexes were carried out and obvious increase in dissolution rate was observed when compared with pure CAB drug and the complexes.

Use of Spray-Dried Dispersions in Early Pharmaceutical Development: Theoretical and Practical Challenges.

PubMed

Li, Jinjiang; Patel, Dhaval; Wang, George

2017-03-01

Spray-dried dispersions (SDDs) have become an important formulation technology for the pharmaceutical product development of poorly water-soluble (PWS) compounds. Although this technology is now widely used in the industry, especially in the early-phase development, the lack of mechanistic understanding still causes difficulty in selecting excipients and predicting stability of SDD-based drug products. In this review, the authors aim to discuss several principles of polymer science pertaining to the development of SDDs, in terms of selecting polymers and solvents, optimizing drug loading, as well as assessing physical stability on storage and supersaturation maintenance after dissolution, from both thermodynamic and kinetic considerations. In order to choose compatible solvents with both polymers and active pharmaceutical ingredients (APIs), a symmetric Flory-Huggins interaction (Δχ ∼0) approach was introduced. Regarding spray drying of polymer-API solutions, low critical solution temperature (LCST) was discussed for setting the inlet temperature for drying. In addition, after being exposed to moisture, SDDs are practically converted to ternary systems with asymmetric Flory-Huggins interactions, which are thermodynamically not favored. In this case, the kinetics of phase separation plays a significant role during the storage and dissolution of SDD-based drug products. The impact of polymers on the supersaturation maintenance of APIs in dissolution media was also discussed. Moreover, the nature of SDDs, with reference to solid solution and the notion of solid solubility, was examined in the context of pharmaceutical application. Finally, the importance of robust analytical techniques to characterize the SDD-based drug products was emphasized, considering their complexity.

[Study on solid dispersion of precipitated calcium carbonate-based oleanolic acid].

PubMed

Yan, Hong-mei; Zhang, Zhen-hai; Jia, Xiao-bin; Jiang, Yan-rong; Sun, E

2015-05-01

Oleanolic acid-precipitated calcium carbonate solid dispersion was prepared by using solvent evaporation method. The microscopic structure and physicochemical properties of solid dispersion were analyzed using differential scanning calorimetry and scanning electron microscopy (SEM). And its in vitro release also was investigated. The properties of the precipitated calcium carbonate was studied which was as a carrier of oleanolic acid solid dispersion. Differential scanning calorimetry analysis suggested that oleanolic acid may be present in solid dispersion as amorphous substance. The in vitro release determination results of oleanolic acid-precipitated calcium carbonate (1: 5) solid dispersion showed accumulated dissolution rate of.oleanolic acid was up to 90% at 45 min. Accelerating experiment showed that content and in vitro dissolution of oleanolic acid solid dispersion did not change after storing over 6 months. The results indicated that in vitro dissolution of oleanolic acid was improved greatly by the solid dispersion with precipitated calcium carbonate as a carrier. The solid dispersion is a stabilizing system which has actual applied value.

Curcumin phytosomal softgel formulation: Development, optimization and physicochemical characterization.

PubMed

Allam, Ahmed N; Komeil, Ibrahim A; Abdallah, Ossama Y

2015-09-01

Curcumin, a naturally occurring lipophilic molecule can exert multiple and diverse bioactivities. However, its limited aqueous solubility and extensive presystemic metabolism restrict its bioavailability. Curcumin phytosomes were prepared by a simple solvent evaporation method where free flowing powder was obtained in addition to a newly developed semisolid formulation to increase curcumin content in softgels. Phytosomal powder was characterized in terms of drug content and zeta potential. Thirteen different softgel formulations were developed using oils such as Miglyol 812, castor oil and oleic acid, a hydrophilic vehicle such as PEG 400 and bioactive surfactants such as Cremophor EL and KLS P 124. Selected formulations were characterized in terms of curcumin in vitro dissolution. TEM analysis revealed good stability and a spherical, self-closed structure of curcumin phytosomes in complex formulations. Stability studies of chosen formulations prepared using the hydrophilic vehicle revealed a stable curcumin dissolution pattern. In contrast, a dramatic decrease in curcumin dissolution was observed in case of phytosomes formulated in oily vehicles.

All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application.

PubMed

Ghaderi, Moein; Mousavi, Mohammad; Yousefi, Hossein; Labbafi, Mohsen

2014-04-15

All-cellulose nanocomposite (ACNC) film was produced from sugarcane bagasse nanofibers using N,N-dimethylacetamide/lithium chloride solvent. The average diameter of bagasse fibers (14 μm) was downsized to 39 nm after disk grinding process. X-ray diffraction showed that apparent crystallinity and crystallite size decreased relatively to an increased duration of dissolution time. Thermogravimetric analysis confirmed that thermal stability of the ACNC was slightly less than that of the pure cellulose nanofiber sheet. Tensile strength of the fiber sheet, nanofiber sheet and ACNC prepared with 10 min dissolution time were 8, 101 and 140 MPa, respectively. Water vapor permeability (WVP) of the ACNC film increased relatively to an increased duration of dissolution time. ACNC can be considered as a multi-performance material with potential for application in cellulose-based food packaging owing to its promising properties (tough, bio-based, biodegradable and acceptable levels of WVP). Copyright © 2014 Elsevier Ltd. All rights reserved.

Derate Mitigation Options for Pulverized Coal Power Plant Carbon Capture Retrofits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffmann, Jeffrey W.; Hackett, Gregory A.; Lewis, Eric G.

Carbon capture and storage (CCS) technologies available in the near-term for pulverized coal-fueled power plants (i.e., post combustion solvent technologies) require substantial capital investment and result in marked decrease in electricity available for sale to the grid. The impact to overall plant economics can be mitigated for new plant designs (where the entire plant can be optimized around the CCS system). However, existing coal-fueled power plants were designed without the knowledge or intent to retrofit a CCS process, and it is simply not possible to re-engineer an existing plant in a manner that it could achieve the same performance asmore » if it was originally designed and optimized for CCS technology. Pairing an auxiliary steam supply to the capture system is a technically feasible option to mitigate the derate resulting from diverting steam away from an existing steam turbine and continuing to run that turbine at steam flow rates and properties outside of the original design specifications. The results of this analysis strongly support the merits of meeting the steam and power requirements for a retrofitted post-combustion solvent based carbon dioxide (CO2) capture system with an auxiliary combined heat and power (CHP) plant rather than robbing the base plant (i.e., diverting steam from the existing steam cycle and electricity from sale to the grid).« less

Plan for radionuclide tracer studies of the residence time distribution in the Wilsonville dissolver and preheater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jolley, R.L.; Begovich, J.M.; Brashear, H.R.

1983-12-01

Stimulus-response measurements using radiotracers to measure residence time distribution (RTD) and hydrodynamic parameters for the preheaters and dissolvers at the Ft. Lewis Solvent Refined Coal (SRC) and the Exxon Donor Solvent (EDS) coal conversion pilot plants are reviewed. A plan is also presented for a series of radioactive tracer studies proposed for the Advanced Coal Liquefaction Facility at Wilsonville, Alabama, to measure the RTD for the preheater and dissolvers in the SRC-I mode. The tracer for the gas phase will be /sup 133/Xe, and /sup 198/Au (on carbonized resin or as an aqueous colloidal suspension) will be used as themore » slurry tracer. Four experimental phases are recommended for the RTD tracer studies: (1) preheater; (2) dissolver with 100% takeoff; (3) dissolver with 100% takeoff and solids withdrawal; and (4) dissolver with 50% takeoff. Eighteen gas-tracer and 22 liquid-tracer injections are projected to accomplish the four experimental phases. Two to four tracer injections are projected for preliminary tests to ensure the capability of safe injection of the radiotracers and the collection of statistically significant data. A complete projected cost and time schedule is provided, including procurement of necessary components, preparation of the radiotracers, assembly and testing of tracer injection apparatus and detection systems, onsite work and tracer injections, laboratory experimentation, data analysis, and report writing.« less

Impact of meteorology and energy structure on solvent extractable organic compounds of PM2.5 in Beijing, China.

PubMed

Feng, Jialiang; Chan, Chak K; Fang, Ming; Hu, Min; He, Lingyan; Tang, Xiaoyan

2005-11-01

Twenty-eight PM2.5 samples collected in Summer (July 2002) and Winter (November 2002) at two sites in Beijing, China were analyzed using GC/MS to investigate the impact of meteorology and coal burning on the solvent extractable organic compounds (SEOC). The characteristics and abundance of the n-alkanes, polycyclic aromatic hydrocarbons (PAHs), n-fatty acids and n-alkanols were determined. Source identification was made using organic species as molecular markers. Semi-volatile compounds of alkanes and PAHs had much higher concentrations in winter than summer because of the large difference in the temperature between the seasons. Plant wax emission was a major contributor to n-alkanes in summer, but fossil fuel residue was a major source (>80%) in winter. The seasonal differences in the distribution of pentacyclic triterpanes clearly shows the impact of coal burning for space heating in winter. The yield of PAHs in winter (148 ng m(-3) at the urban site and 277 ng m(-3) at the suburban site) was six to eight times higher than that in summer and was found to be mainly from coal burning. Higher pollutant concentrations were measured at the suburban site than the urban site in winter due to the rapid expansion of the city limit and the relocation of factories from urban to suburban areas over the last two decades.

Hindered diffusion of coal liquids. Quarterly report No. 12, June 18, 1995--September 17, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsotsis, T.T.; Sahimi, M.; Webster, I.A.

1995-12-31

The design of industrial catalysts requires that the diffusivity of the reacting species within the catalyst be accurately known. Nowhere is this more important than in the area of coal liquefaction and upgrading of coal liquids. In this area one is faced with the task of processing a number of heavy oils, containing metals and other contaminants, in a variety of process dependent solvents. It is important, therefore, on the basis of predicting catalyst activity, selectivity, and optimizing reactor performance, that the diffusivities of these oil species be accurately known. It is the purpose of the project described here tomore » provide such a correct concept of coal asphaltenes by careful and detailed investigations of asphaltene transport through porous systems under realistic process temperature and pressure conditions. The experimental studies will be coupled with detailed, in-depth statistical and molecular dynamics models intended to provide a fundamental understanding of the overall transport mechanisms.« less

Refining of fossil resin flotation concentrates from Western coal. Final fifth quarterly report, January 1, 1994--March 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, G.F.; Miller, J.D.

1994-05-07

Fossil resins occurring in the Wasatch Plateau coal field are composed mainly of aliphatic components, partially aromatized multi-cyclic terpenoids and a few oxygen functional groups (such as {minus}OH and {minus}COOH). The solvent extracted resins show the presence of a relatively large number of methyl groups when compared to the methylene groups, and this indicates the presence of extensive tertiary carbon and/or highly branching chains. In contrast coal consists primarily of aromatic ring structures, various oxygen functional groups ({minus}OH, >C=O, {minus}C{minus}O) and few aliphatic chains. The color difference observed among the four resin types is explained by the presence of chromophoresmore » (aromatized polyterpenoid) and also by the presence of finely dispersed coal particle inclusions in the resin matrix. The hexane soluble resin fraction has few aromatic compounds when compared to the hexane insoluble but toluene soluble resin fraction.« less

Enhanced dissolution and oral bioavailability of valsartan solid dispersions prepared by a freeze-drying technique using hydrophilic polymers.

PubMed

Xu, Wei-Juan; Xie, Hong-Juan; Cao, Qing-Ri; Shi, Li-Li; Cao, Yue; Zhu, Xiao-Yin; Cui, Jing-Hao

2016-01-01

This study aimed to improve the dissolution rate and oral bioavailability of valsartan (VAL), a poorly soluble drug using solid dispersions (SDs). The SDs were prepared by a freeze-drying technique with polyethylene glycol 6000 (PEG6000) and hydroxypropylmethylcellulose (HPMC 100KV) as hydrophilic polymers, sodium hydroxide (NaOH) as an alkalizer, and poloxamer 188 as a surfactant without using any organic solvents. In vitro dissolution rate and physicochemical properties of the SDs were characterized using the USP paddle method, differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and Fourier transform-infrared (FT-IR) spectroscopy, respectively. In addition, the oral bioavailability of SDs in rats was evaluated by using VAL (pure drug) as a reference. The dissolution rates of the SDs were significantly improved at pH 1.2 and pH 6.8 compared to those of the pure drug. The results from DSC, XRD showed that VAL was molecularly dispersed in the SDs as an amorphous form. The FT-IR results suggested that intermolecular hydrogen bonding had formed between VAL and its carriers. The SDs exhibited significantly higher values of AUC 0-24 h and Cmax in comparison with the pure drug. In conclusion, hydrophilic polymer-based SDs prepared by a freeze-drying technique can be a promising method to enhance dissolution rate and oral bioavailability of VAL.

Remediation of Contaminated Soils By Supercritical Carbon Dioxide Extraction

NASA Astrophysics Data System (ADS)

Ferri, A.; Zanetti, M. C.; Banchero, M.; Fiore, S.; Manna, L.

The contaminants that can be found in soils are many, inorganic, like heavy metals, as well as organic. Among the organic contaminants, oil and coal refineries are responsi- ble for several cases of soil contamination with PAHs (Polycyclic Aromatic Hydrocar- bons). Polynuclear aromatic hydrocarbons (PAHs) have toxic, carcinogenic and mu- tagenic effects. Limits have been set on the concentration of most contaminants, and growing concern is focusing on soil contamination issues. USA regulations set the maximum acceptable level of contamination by PAHs equal to 40 ppm at residential sites and 270 ppm at industrial sites. Stricter values are usually adopted in European Countries. Supercritical carbon dioxide extraction is a possible alternative technology to remove volatile organic compounds from contaminated soils. Supercritical fluid extraction (SFE) offers many advantages over conventional solvent extraction. Super- critical fluids combine gaseous properties as a high diffusion coefficient, and liquid properties as a high solvent power. The solvent power is strongly pressure-dependent near supercritical conditions: selective extractions are possible without changing the solvent. Solute can be separate from the solvent depressurising the system; therefore, it is possible to recycle the solvent and recover the contaminant. Carbon dioxide is frequently used as supercritical fluid, because it has moderate critical conditions, it is inert and available in pure form. In this work, supercritical fluid extraction technology has been used to remove a polynuclear aromatic hydrocarbon from contaminated soils. The contaminant choice for the experiment has been naphthalene since several data are available in literature. G. A. Montero et al. [1] studied soil remediation with supercrit- ical carbon dioxide extraction technology; these Authors have found that there was a mass-transfer limitation. In the extraction vessel, the mass transfer coefficient in- creases with the superficial velocity of the supercritical carbon dioxide; therefore, the mass transfer resistance can be reduced increasing such velocity. In this work, higher values of superficial velocity were investigated. The experimental apparatus includes a pump, an extraction vessel, an adjustable restrictor and a trap to collect the extracted substance. Liquid carbon dioxide coming from a cylinder with a dip-tube is cooled by a cryostatic bath and then it is compressed by a pneumatic drive pump (the max- imum available pressure is 69 MPa). Subsequently, the pressurised current flows into 1 a heating coil and then into the extraction vessel, which is contained in a stove; the outlet flow is depressurised in an adjustable restrictor and the extracted substance is collected in a trap by dissolution into a solvent. The extracted naphthalene quantity was obtained by weighting the solvent and measuring the naphthalene concentration with a gas chromatograph. The soil sample is a sandy soil geologically representative of the North of Italy that was sampled and physically and chemically characterized: particle-size distribution analysis, diffractometric analysis, Cation Exchange Capac- ity, Total Organic Carbon, iron content and manganese content in order to evaluate the potential sorption degree. The soil was artificially polluted by means of a naphta- lene and methylene chloride solution. The experimental work consists in a number of naphthalene extractions from the spiked soil, that were carried out at different operat- ing conditions, temperature, pressure and flow rate by means of supercritical carbon dioxide evaluating the corresponding recovery efficiencies. The results obtained were analysed and compared in order to determine which parameters influence the system. [1] G. A. Montero, T.D. Giorgio, and K. B. Schnelle, Jr..Removal of Hazardous ,1994, Contaminants form Soils by Supercritical Fluid Extraction. Innovations in Supercriti- cal Fluids. ACS Symposium Series, 608, 280-197. 2

[Preparation and quality control of pyridostigmine bromide orally disintegrating tablet].

PubMed

Zhang, Li; Tan, Qun-you; Cheng, Xun-guan; Wang, Hong; Hu, Ni-ni; Zhang, Jing-qing

2012-05-01

To prepare orally disintegrating tablets containing pyridostigmine bromide and optimize formulations. Solid dispersion was prepared using solvent evaporation-deposition method. The formulation was optimized by central composite design-response surface methodology (RSM plus CCD) with disintegration time as a reference parameter. The orally disintegrating tablets showed integrity and were smooth with desirable taste and feel in mouth. The disintegration time was less than 30 s. The cumulative drug dissolution was around 8.5% (around 2.5 mg which was less than bitterness threshold of pyridostigmine bromide of 3 mg) within 5 min in water while the cumulative drug dissolution was higher than 95% within 2 min in 0.1 N HCl. The orally disintegrating tablets are reasonable in formulation, feasible in technology and patient-friendly.

Complexation of furosemide with fulvic acid extracted from shilajit: a novel approach.

PubMed

Agarwal, Suraj Prakash; Anwer, Mohammad Khalid; Aqil, Mohammad

2008-05-01

The aim of the present work was to complex furosemide (FSM) with fulvic acid (FA) extracted from shilajit with the hope of having a better understanding of the complexation behavior. The effect of FA on the aqueous solubility, dissolution rate, and permeability of FSM was investigated. Different techniques, such as grinding, freeze drying, solvent evaporation, and so forth, were used for the preparation of the complex. The complexes were prepared in molar ratios of 1:1 and 1:2 FSM:FA and were evaluated for drug inclusion, solubility, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, dissolution study, and permeation study. These methods confirm the formation of an amorphous inclusion complex of FSM with FA.

Method for the decontamination of soil containing solid organic explosives therein

DOEpatents

Radtke, Corey W.; Roberto, Francisco F.

2000-01-01

An efficient method for decontaminating soil containing organic explosives ("TNT" and others) in the form of solid portions or chunks which are not ordinarily subject to effective bacterial degradation. The contaminated soil is treated by delivering an organic solvent to the soil which is capable of dissolving the explosives. This process makes the explosives more bioavailable to natural bacteria in the soil which can decompose the explosives. An organic nutrient composition is also preferably added to facilitate decomposition and yield a compost product. After dissolution, the explosives are allowed to remain in the soil until they are decomposed by the bacteria. Decomposition occurs directly in the soil which avoids the need to remove both the explosives and the solvents (which either evaporate or are decomposed by the bacteria). Decomposition is directly facilitated by the solvent pre-treatment process described above which enables rapid bacterial remediation of the soil.

Three dimensional ink-jet printing of biomaterials using ionic liquids and co-solvents.

PubMed

Gunasekera, Deshani H A T; Kuek, SzeLee; Hasanaj, Denis; He, Yinfeng; Tuck, Christopher; Croft, Anna K; Wildman, Ricky D

2016-08-15

1-Ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-methylimidazolium acetate ([C4C1Im][OAc]) have been used as solvents for the dissolution and ink-jet printing of cellulose from 1.0 to 4.8 wt%, mixed with the co-solvents 1-butanol and DMSO. 1-Butanol and DMSO were used as rheological modifiers to ensure consistent printing, with DMSO in the range of 41-47 wt% producing samples within the printable range of a DIMATIX print-head used (printability parameter < 10) at 55 °C, whilst maintaining cellulose solubility. Regeneration of cellulose from printed samples using water was demonstrated, with the resulting structural changes to the cellulose sample assessed by scanning electron microscopy (SEM) and white light interferometry (WLI). These results indicate the potential of biorenewable materials to be used in the 3D additive manufacture process to generate single-component and composite materials.

Dynamic nuclear polarization in solid samples by electrical-discharge-induced radicals

NASA Astrophysics Data System (ADS)

Katz, Itai; Blank, Aharon

2015-12-01

Dynamic nuclear polarization (DNP) is a method for enhancing nuclear magnetic resonance (NMR) signals that has many potential applications in chemistry and medicine. Traditionally, DNP signal enhancement is achieved through the use of exogenous radicals mixed in a solution with the molecules of interest. Here we show that proton DNP signal enhancements can be obtained for solid samples without the use of solvent and exogenous radicals. Radicals are generated primarily on the surface of a solid sample using electrical discharges. These radicals are found suitable for DNP. They are stable under moderate vacuum conditions, yet readily annihilate upon compound dissolution or air exposure. This feature makes them attractive for use in medical applications, where the current variety of radicals used for DNP faces regulatory problems. In addition, this solvent-free method may be found useful for analytical NMR of solid samples which cannot tolerate solvents, such as certain pharmaceutical products.

Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.

2013-04-01

Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotopemore » mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.« less

Effect of casting solvent on crystallinity of ondansetron in transdermal films.

PubMed

Pattnaik, Satyanarayan; Swain, Kalpana; Mallick, Subrata; Lin, Zhiqun

2011-03-15

The purpose of the present investigation is to assess the influence of casting solvent on crystallinity of ondansetron hydrochloride in transdermal polymeric matrix films fabricated using povidone and ethyl cellulose as matrix forming polymers. Various casting solvents like chloroform (CHL), dichloromethane (DCM), methanol (MET); and mixture of chloroform and ethanol (C-ETH) were used for fabrication of the transdermal films. Analytical tools like scanning electron microscopy (SEM), X-ray diffraction (XRD) studies, differential scanning calorimetry (DSC), etc. were utilized to characterize the crystalline state of ondansetron in the film. Recrystallisation was observed in all the transdermal films fabricated using the casting solvents other than chloroform. Long thin slab-looking, long wire-like or spherulite-looking crystals with beautiful impinged boundaries were observed in SEM. Moreover, XRD revealed no crystalline peaks of ondansetron hydrochloride in the transdermal films prepared using chloroform as casting solvent. The significantly decreased intensity and sharpness of the DSC endothermic peaks corresponding to the melting point of ondansetron in the formulation (specifically in CHL) indicated partial dissolution of ondansetron crystals in the polymeric films. The employed analytical tools suggested chloroform as a preferred casting solvent with minimum or practically absence of recrystallization indicating a relatively amorphous state of ondansetron in transdermal films. Copyright © 2011 Elsevier B.V. All rights reserved.

Solvent properties of hydrazine in the preparation of metal chalcogenide bulk materials and films.

PubMed

Yuan, Min; Mitzi, David B

2009-08-21

A combination of unique solvent properties of hydrazine enables the direct dissolution of a range of metal chalcogenides at ambient temperature, rendering this an extraordinarily simple and soft synthetic approach to prepare new metal chalcogenide-based materials. The extended metal chalcogenide parent framework is broken up during this process, and the resulting metal chalcogenide building units are re-organized into network structures (from 0D to 3D) based upon their interactions with the hydrazine/hydrazinium moieties. This Perspective will review recent crystal and materials chemistry developments within this family of compounds and will briefly discuss the utility of this approach in metal chalcogenide thin-film deposition.

Flow behavior of regenerated wool-keratin proteins in different mediums.

PubMed

Alemdar, Ayse; Iridag, Yesim; Kazanci, Murat

2005-04-01

Keratin is abundantly present in nature and the major component of hair, wool, feather, nail and horns. Dissolution of keratin is often required when non-textile applications are demanded. However, the low solubility of keratin in water is the major problem. It becomes unstable and precipitated when stored for a long time. Therefore, it is necessary to find a good solvent that provides high stability and easy processibility. In this research, we used formic acid and dimethylformamide (DMF) to dissolve regenerated keratin protein films. It is shown that formic acid is a good solvent for regenerated keratin proteins for the purpose of storage. Transparent and stable regenerated keratin solution is obtained in formic acid.

Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, January--March 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, C.W.

Previous research has suggested that using a more effective hydrogen donor solvent in the low severity coal liquefaction reaction improves coal conversion. In order to understand the results of these methods, both independently and combined, a factorial experiment was designed. Pretreating coal with hydrochloric and sulfurous acid solutions in both water and methanol is compared with pretreating coal using only methanol and with no pretreatment. The effects of these pretreatments on coal liquefaction behavior are contrasted with the ammonium acetate pretreatment. Within each of these, individual reactions are performed with the hydroaromatic 1,2,3,4-tetrahydronaphthalene (tetralin, TET) and the cyclic olefin 1,4,5,8-tetrahydronaphthalenemore » (isotetralin, ISO). The final aspect of the factorial experiment is the comparison of Wyodak subbituminous coal (WY) from the Argonne Premium Sample Bank and Black Thunder subbituminous coal (BT) provided by Amoco. Half of the reactions in the matrix have now been completed. In all but one case, Black Thunder-HCl/H{sub 2}O, the ISO proved to be more reactive than TET. After the other four reactions using this combination are complete, the average conversion may be greater with the cyclic olefin. The second part of this paper describes the current and future work with Fourier transform infrared spectroscopy. The objective of this work is to determine the kinetics of reaction of isotetralin at high temperatures and pressures. This quarter combinations of three products typically produced from isotetralin were used in spectral subtraction.« less

Adsorption onto Mesoporous Silica Using Supercritical Fluid Technology Improves Dissolution Rate of Carbamazepine-a Poorly Soluble Compound.

PubMed

Gandhi, Aditya V; Thipsay, Priyanka; Kirthivasan, Bharat; Squillante, Emilio

2017-11-01

The purpose of this research was to design and characterize an immediate-release formulation of carbamazepine (CBZ), a poorly soluble anti-epileptic drug, using a porous silica carrier. Carbon dioxide in its supercritical state (2000 psi, 30-35°C) was used as an anti-solvent to precipitate CBZ onto two particle size variants of silica. Adsorption isotherms were used as a pre-formulation strategy to select optimum ratios of silica and CBZ. The obtained drug-silica formulations were characterized by dissolution studies, differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). This formulation strategy resulted in a 2.4-fold improvement in dissolution rate when compared to pure drug after 30 min of dissolution testing. PXRD and DSC confirmed the amorphous nature of CBZ in the formulations as well as the differences in polymorphic forms of commercial and supercritical fluid-processed CBZ. Additionally, solid-state NMR spectroscopy showed that the spin-lattice relaxation time for bulk drug (without silica) was ∼7.5 times greater than that for silica-confined CBZ, implying that when CBZ was adsorbed onto mesoporous silica, it is structurally disordered and had higher structural mobility, a characteristic of amorphous solids. The mesoporous silica matrix prevented CBZ crystal growth by imposing spatial constraint on CBZ nuclei and hence resulted in faster dissolution compared to bulk solid drug. Adsorption onto mesoporous silica using supercritical fluid technology may be used as a novel formulation strategy for amorphization of poorly soluble compounds, in turn improving their dissolution rate.

Comprehensive Model for Enhanced Biodegradation of Chlorinated Solvents in Groundwater

NASA Astrophysics Data System (ADS)

Kouznetsova, I.; Gerhard, J. I.; Mao, X.; Robinson, C.; Barry, A. D.; Harkness, M.; Mack, E. E.; Dworatzek, S.

2007-12-01

SABRE (Source Area BioREmediation) is a public/private consortium whose charter is to de-termine if enhanced anaerobic bioremediation can result in effective treatment of chlorinated solvent DNAPL source areas. The focus of this 4-year, $5.7 million research and development project is a field site in the United Kingdom containing TCE DNAPL. A comprehensive numerical model for simulating dehalogenation of chlorinated ethenes has been developed. The model considers the kinetic dissolution of DNAPL and nonaqueous organic amendments, bacterial growth and decay, and the interaction of biological and geochemical reactions that might influence biological activity. The model accounts for inhibitory effects of high chlorin-ated solvent concentrations as well as the link between fermentation and dehalogenation due to dynamic hydrogen concentration (the direct electron donor). In addition to the standard biodegradation pathways, sulphate reduction, mineral dissolution and precipitation kinetics are incorporated. These latter processes influence the soil buffering capacity and thus the net acidity generated. One-dimensional simulations were carried out to reproduce the data from columns packed with site soil and groundwater exhibiting both intermediate (250 mg/L) and near solubility (1100 mg/L) TCE concentrations. The modelling aims were to evaluate the key processes underpinning bioremediation success and provide a tool for investigating field sys-tem sensitivity to site data and design variables. This paper will present the model basis and validation and examine sensitivity to key processes including chlorinated ethene partitioning into soybean oil, sulphate reduction, and geochemical influences such as pH and the role of buffering in highly dechlorinating systems.

Comparative responses of river biofilms at the community level to common organic solvent and herbicide exposure.

PubMed

Paule, A; Roubeix, V; Swerhone, G D W; Roy, J; Lauga, B; Duran, R; Delmas, F; Paul, E; Rols, J L; Lawrence, J R

2016-03-01

Residual pesticides applied to crops migrate from agricultural lands to surface and ground waters. River biofilms are the first aquatic non-target organisms which interact with pesticides. Therefore, ecotoxicological experiments were performed at laboratory scale under controlled conditions to investigate the community-level responses of river biofilms to a chloroacetanilide herbicide (alachlor) and organic solvent (methanol) exposure through the development referenced to control. Triplicate rotating annular bioreactors, inoculated with river water, were used to cultivate river biofilms under the influence of 1 and 10 μg L(-1) of alachlor and 25 mg L(-1) of methanol. For this purpose, functional (thymidine incorporation and carbon utilization spectra) and structural responses of microbial communities were assessed after 5 weeks of development. Structural aspects included biomass (chlorophyll a, confocal laser scanning microscopy) and composition (fluor-conjugated lectin binding, molecular fingerprinting, and diatom species composition). The addition of alachlor resulted in a significant reduction of bacterial biomass at 1 μg L(-1), whereas at 10 μg L(-1), it induced a significant reduction of exopolymer lectin binding, algal, bacterial, and cyanobacterial biomass. However, there were no changes in biofilm thickness or thymidine incorporation. No significant difference between the bacterial community structures of control and alachlor-treated biofilms was revealed by terminal restriction fragment length polymorphism (T-RFLP) analyses. However, the methanol-treated bacterial communities appeared different from control and alachlor-treated communities. Moreover, methanol treatment resulted in an increase of bacterial biomass and thymidine incorporation as well. Changes in dominant lectin binding suggested changes in the exopolymeric substances and community composition. Chlorophyll a and cyanobacterial biomass were also altered by methanol. This study suggested that the concentration-dependent effect of alachlor mainly remains limited to biomass and growth inhibition without apparent changes of structural and functional characteristics measured. Our work also establishes the potential toxic effects of organic solvents on river biofilm in ecotoxicological experiments. For the ecotoxicological experiments, the alternative of dissolution in organic solvent followed by its evaporation, depositing the chemical on a glass surface prior to dissolution in river water used here, appears to allow exposure while minimizing the effect of organic solvent.

Niosh analytical methods for Set G

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1976-12-01

Industrial Hygiene sampling and analytical monitoring methods validated under the joint NIOSH/OSHA Standards Completion Program for Set G are contained herein. Monitoring methods for the following compounds are included: butadiene, heptane, ketene, methyl cyclohexane, octachloronaphthalene, pentachloronaphthalene, petroleum distillates, propylene dichloride, turpentine, dioxane, hexane, LPG, naphtha(coal tar), octane, pentane, propane, and stoddard solvent.

Hydrochemical characterization and pollution sources identification of groundwater in Salawusu aquifer system of Ordos Basin, China.

PubMed

Yang, Qingchun; Wang, Luchen; Ma, Hongyun; Yu, Kun; Martín, Jordi Delgado

2016-09-01

Ordos Basin is located in an arid and semi-arid region of northwestern China, which is the most important energy source bases in China. Salawusu Formation (Q3 s) is one of the most important aquifer systems of Ordos Basin, which is adjacent to Jurassic coalfield areas. A large-scale exploitation of Jurassic coal resources over ten years results in series of influences to the coal minerals, such as exposed to the oxidation process and dissolution into the groundwater due to the precipitation infiltration. Therefore, how these processes impact groundwater quality is of great concerns. In this paper, the descriptive statistical method, Piper trilinear diagram, ratios of major ions and canonical correspondence analysis are employed to investigate the hydrochemical evolution, determine the possible sources of pollution processes, and assess the controls on groundwater compositions using the monitored data in 2004 and 2014 (before and after large-scale coal mining). Results showed that long-term exploration of coal resources do not result in serious groundwater pollution. The hydrochemical types changed from HCO3(-)-CO3(2-) facies to SO4(2-)-Cl facies during 10 years. Groundwater hardness, nitrate and sulfate pollution were identified in 2014, which was most likely caused by agricultural activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced oral bioavailability of fenofibrate using polymeric nanoparticulated systems: physicochemical characterization and in vivo investigation

PubMed Central

Yousaf, Abid Mehmood; Kim, Dong Wuk; Oh, Yu-Kyoung; Yong, Chul Soon; Kim, Jong Oh; Choi, Han-Gon

2015-01-01

Background The intention of this research was to prepare and compare various solubility-enhancing nanoparticulated systems in order to select a nanoparticulated formulation with the most improved oral bioavailability of poorly water-soluble fenofibrate. Methods The most appropriate excipients for different nanoparticulated preparations were selected by determining the drug solubility in 1% (w/v) aqueous solutions of each carrier. The polyvinylpyrrolidone (PVP) nanospheres, hydroxypropyl-β-cyclodextrin (HP-β-CD) nanocorpuscles, and gelatin nanocapsules were formulated as fenofibrate/PVP/sodium lauryl sulfate (SLS), fenofibrate/HP-β-CD, and fenofibrate/gelatin at the optimized weight ratios of 2.5:4.5:1, 1:4, and 1:8, respectively. The three solid-state products were achieved using the solvent-evaporation method through the spray-drying technique. The physicochemical characterization of these nanoparticles was accomplished by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Their physicochemical properties, aqueous solubility, dissolution rate, and pharmacokinetics in rats were investigated in comparison with the drug powder. Results Among the tested carriers, PVP, HP-β-CD, gelatin, and SLS showed better solubility and were selected as the most appropriate constituents for various nanoparticulated systems. All of the formulations significantly improved the aqueous solubility, dissolution rate, and oral bioavailability of fenofibrate compared to the drug powder. The drug was present in the amorphous form in HP-β-CD nanocorpuscles; however, in other formulations, it existed in the crystalline state with a reduced intensity. The aqueous solubility and dissolution rates of the nanoparticles (after 30 minutes) were not significantly different from one another. Among the nanoparticulated systems tested in this study, the initial dissolution rates (up to 10 minutes) were higher with the PVP nanospheres and HP-β-CD nanocorpuscles; however, neither of them resulted in the highest oral bioavailability. Irrespective of relatively retarded dissolution rate, gelatin nanocapsules showed the highest apparent aqueous solubility and furnished the most improved oral bioavailability of the drug (~5.5-fold), owing to better wetting and diminution in crystallinity. Conclusion Fenofibrate-loaded gelatin nanocapsules prepared using the solvent-evaporation method through the spray-drying technique could be a potential oral pharmaceutical product for administering the poorly water-soluble fenofibrate with an enhanced bioavailability. PMID:25784807

Health effects research in direct coal liquefaction. Studies of H-coal distillates: Phase I. PDU samples - the effects of hydrotreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epler, J.L.; Fry, R.J.M.; Larimer, F.W.

1981-11-01

A multi-divisional effort aimed at the integrated assessment of the health and environmental effects of various coal conversion and shale oil technologies is being carried out. The feasibility of using health effects bioassays to predict the potential biohazard of various H-Coal derived test materials is examined in a coupled chemical and biological approach. The primary focus of the research is the use of preliminary chemical characterizations and preparation for bioassay, followed by testing in short-term assays in order to rapidly ascertain the potential biohazard. Mammalian toxicological assays parallel the testing. Raw and hydrotreated product liquids from process development units ofmore » H-Coal and the pilot plant solvent refined coal process were examined for acute toxicity monitored as population growth impairment of Tetrahymena exposed to aqueous extracts and for mutagenic activity monitored as revertants of Salmonella exposed to metabolically activated chemical class fractions. Medium to high severity hydrotreatment appears to be an effective means of reducing biological activity, presumably by reducing the aromaticity and heteroatom content. Five basic mammalian, acute toxicity tests have been conducted with selected H-coal samples and shale oil derivatives. The data show that H-Coal samples are moderately toxic whereas the toxicity of shale oil derived products is slight and comparable to samples obtained from naturally occurring petroleums. No overt skin or eye toxicity was found. The present data reveal that coal-derived distillates generated by the H-coal process are highly carcinogenic to mouse skin. An extreme form of neurotoxicity associated with dermal exposure to one of the lighter, minimally carcinogenic, materials was noted. (DMC)« less

Direct liquefaction of plastics and coprocessing of coal with plastics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huffman, G.P.; Feng, Z.; Mahajan, V.

1995-12-31

The objectives of this work were to optimize reaction conditions for the direct liquefaction of waste plastics and the coprocessing of coal with waste plastics. In previous work, the direct liquefaction of medium and high density polyethylene (PE), polypropylene (PPE), poly(ethylene terephthalate) (PET), and a mixed plastic waste, and the coliquefaction of these plastics with coals of three different ranks was studied. The results established that a solid acid catalyst (HZSM-5 zeolite) was highly active for the liquefaction of the plastics alone, typically giving oil yields of 80-95% and total conversions of 90-100% at temperatures of 430-450 {degrees}C. In themore » coliquefaction experiments, 50:50 mixtures of plastic and coal were used with a tetralin solvent (tetralin:solid = 3:2). Using approximately 1% of the HZSM-5 catalyst and a nanoscale iron catalyst, oil yields of 50-70% and total conversion of 80-90% were typical. In the current year, further investigations were conducted of the liquefaction of PE, PPE, and a commingled waste plastic obtained from the American Plastics Council (APC), and the coprocessing of PE, PPE and the APC plastic with Black Thunder subbituminous coal. Several different catalysts were used in these studies.« less

Apparatus and methods for regeneration of precipitating solvent

DOEpatents

Liu, Guohai; Vimalchand, Pannalal; Peng, Wan Wang; Bonsu, Alexander

2015-08-25

A regenerator that can handle rich loaded chemical solvent containing precipitated absorption reaction products is disclosed. The invention is particularly suitable for separating CO.sub.2 from large gas streams that are typical of power plant processes. The internally circulating liquid stream in the regenerator (ICLS regenerator) rapidly heats-up the in-coming rich solvent stream in a downcomer standpipe as well as decreases the overall concentration of CO.sub.2 in the mixed stream. Both these actions lead to dissolution of precipitates. Any remaining precipitate further dissolves as heat is transferred to the mixed solution with an inverted bayonet tube heat exchanger in the riser portion of the regenerator. The evolving CO.sub.2 bubbles in the riser portion of the regenerator lead to substantial gas hold-up and the large density difference between the solutions in the downcomer standpipe and riser portions promotes internal circulation of the liquid stream in the regenerator. As minor amounts of solvent components present in the exit gas stream are condensed and returned back to the regenerator, pure CO.sub.2 gas stream exits the disclosed regenerator and condenser system.

Deterred drug abuse using superabsorbent polymers.

PubMed

Mastropietro, David J; Muppalaneni, Srinath; Omidian, Hossein

2016-11-01

This study aimed to determine whether selected superabsorbent polymers (SAPs) could be used as a suitable alternative to thwart extraction, filtration, and syringeability attempts for abuse. Many abuse-deterrent formulations (ADFs) rely on high molecular weight polymers such as poly(ethylene oxide) to provide crush and extraction resistance. However, these polymers suffer from slow dissolution kinetics, and are susceptible to a variety of abuse conditions. Several commercially available SAPs were evaluated for swelling behavior in extraction solvents, and tableting properties. Post-compaction abuse properties were evaluated by recoverable volume and syringeability after solvent extraction. Drug release and percent drug extraction were conducted using tramadol HCl as a model drug. Certain SAPs had the ability to rapidly imbibe solvent and effectively stop extraction processes in a variety of solvents, including water and water/alcohol mixtures. Tablets containing SAP and drug showed no effect on drug release in vitro. SAPs possess adequate properties for tableting, and maintain their high and fast swelling properties after compaction. The fast and extensive interactions of SAPs with aqueous medium are a major advantage over non-crosslinked high molecular weight viscosifying agents such as poly(ethylene oxide).

An NMR (Nuclear Magnetic Resonance) Investigation of the Chemical Association and Molecular Dynamics in Asphalt Ridge Tar Sand Ore and Bitumen

DOE R&D Accomplishments Database

Netzel, D. A.; Coover, P. T.

1987-09-01

Preliminary studies on tar sand bitumen given in this report have shown that the reassociation of tar sand bitumen to its original molecular configuration after thermal stressing is a first-order process requiring nearly a week to establish equilibrium. Studies were also conducted on the dissolution of tar sand bitumen in solvents of varying polarity. At a high-weight fraction of solute to solvent the apparent molecular weight of the bitumen molecules was greater than that of the original bitumen when dissolved in chloroform-d{sub 1} and benzene-d{sub 6}. This increase in the apparent molecular weight may be due to micellar formation or a weak solute-solvent molecular complex. Upon further dilution with any of the solvents studied, the apparent molecular weight of the tar sand bitumen decreased because of reduced van der Waals forces of interaction and/or hydrogen bonding. To define the exact nature of the interactions, it will be necessary to have viscosity measurements of the solutions.

Preparation and in vitro/in vivo evaluation of PLGA microspheres containing norquetiapine for long-acting injection.

PubMed

Park, Chun-Woong; Lee, Hyo-Jung; Oh, Dong-Won; Kang, Ji-Hyun; Han, Chang-Soo; Kim, Dong-Wook

2018-01-01

Norquetiapine ( N -desalkyl quetiapine, NQ) is an active metabolite of quetiapine with stable pharmacokinetic and pharmacological properties. However, its short half-life is a drawback for clinical applications, and long-acting formulations are required. The objectives of this study were to prepare improved entrapment efficiency NQ freebase microspheres by the solvent evaporation method with poly(d,l-lactic-co-glycolic acid) (PLGA) as a release modulator and to evaluate their physicochemical and in vitro/in vivo release properties. NQ freebase PLGA (1:5 w/w) formulations were prepared by the oil-in-water (o/w) emulsion-solvent evaporation method. A solution of the drug and PLGA in 9:1 v/v dichloromethane:ethanol was mixed with 0.2% polyvinyl alcohol and homogenized at 2,800 rpm. The emulsion was stirred for 3 h to dilute and evaporate the solvent. After that, the resulting product was freeze-dried. Drug-loading capacity was measured by the validated RP-HPLC method. The surface morphology of the microspheres was observed by scanning electron microscopy (SEM), and the physicochemical properties were evaluated by differential scanning calorimetry, powder X-ray diffraction, and Fourier-transform infrared spectroscopy particle size distribution. The in vitro dissolution test was performed using a rotary shaking bath at 37°C, with constant shaking at 50 rpm in sink condition. The NQ freebase microspheres prepared by o/w emulsion-solvent evaporation showed over 30% efficiency. NQ was confirmed to be amorphous in the microspheres by powder X-ray diffraction and differential scanning calorimetry. Special chemical interaction in the microspheres was not observed by FT-IR. The in vitro dissolution test demonstrated that the prepared microspheres' release properties were maintained for more than 20 days. The in vivo test also confirmed that the particles' long acting properties were maintained. Therefore, good in vitro-in vivo correlation was established. In this study, NQ freebase-PLGA microspheres showed potential for the treatment of schizophrenia for long-periods.

Bench-Scale Silicone Process for Low-Cost CO{sub 2} Capture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Benjamin; Genovese, Sarah; Perry, Robert

2013-12-31

A bench-scale system was designed and built to test an aminosilicone-based solvent. A model was built of the bench-scale system and this model was scaled up to model the performance of a carbon capture unit, using aminosilicones, for CO{sub 2} capture and sequestration (CCS) for a pulverized coal (PC) boiler at 550 MW. System and economic analysis for the carbon capture unit demonstrates that the aminosilicone solvent has significant advantages relative to a monoethanol amine (MEA)-based system. The CCS energy penalty for MEA is 35.9% and the energy penalty for aminosilicone solvent is 30.4% using a steam temperature of 395more » °C (743 °F). If the steam temperature is lowered to 204 °C (400 °F), the energy penalty for the aminosilicone solvent is reduced to 29%. The increase in cost of electricity (COE) over the non-capture case for MEA is ~109% and increase in COE for aminosilicone solvent is ~98 to 103% depending on the solvent cost at a steam temperature of 395 °C (743 °F). If the steam temperature is lowered to 204 °C (400 °F), the increase in COE for the aminosilicone solvent is reduced to ~95-100%.« less

Determination of oligomers in virgin and recycled polyethylene terephthalate (PET) samples by UPLC-MS-QTOF.

PubMed

Ubeda, Sara; Aznar, Margarita; Nerín, Cristina

2018-03-01

An oligomer is a molecule that consists of a few monomer units. It can be formed during polymer manufacturing and also due to polymer degradation processes or even during use conditions. Since oligomers are not included in chemical databases, their identification is a complex process. In this work, the oligomers present in 20 different PET pellet samples have been determined. Two different sample treatment procedures, solvent extraction and total dissolution, were applied in order to select the most efficient one. The analyses were carried out by UPLC-MS-QTOF. The use of high resolution mass spectrometry allowed the structural elucidation of these compounds and their correct identification. The main oligomers identified were cyclic as well as lineal from the first, second, and third series. All of them were composed of terephthalic acid (TPA), diethylene glycol (DEG), and ethylene glycol (EG). Quantitative values were very different in both procedures. In total dissolution of PET samples, the concentration of oligomers was always, at least, 10 times higher than in solvent extraction; some of the compounds were only detected when total dissolution was used. Results showed that the oligomers with the highest concentration values were dimers and trimers, cyclic, as well as lineal, from the first and second series. The oligomer with the maximum concentration value was TPA 2 -EG-DEG that was found in all the samples in a concentration range from 2493 to 19,290 ng/g PET. No differences between virgin and recycled PET were found. Migration experiments were performed in two PET bottles, and results showed the transference of most of these oligomers to a fat food simulant (ethanol 95%). Graphical abstract Graphical abstract of the two procedures developd and optimized for identifying oligomers in PET pellets and in migration form PET bottles.

Biological reduction of chlorinated solvents: Batch-scale geochemical modeling

NASA Astrophysics Data System (ADS)

Kouznetsova, Irina; Mao, Xiaomin; Robinson, Clare; Barry, D. A.; Gerhard, Jason I.; McCarty, Perry L.

2010-09-01

Simulation of biodegradation of chlorinated solvents in dense non-aqueous phase liquid (DNAPL) source zones requires a model that accounts for the complexity of processes involved and that is consistent with available laboratory studies. This paper describes such a comprehensive modeling framework that includes microbially mediated degradation processes, microbial population growth and decay, geochemical reactions, as well as interphase mass transfer processes such as DNAPL dissolution, gas formation and mineral precipitation/dissolution. All these processes can be in equilibrium or kinetically controlled. A batch modeling example was presented where the degradation of trichloroethene (TCE) and its byproducts and concomitant reactions (e.g., electron donor fermentation, sulfate reduction, pH buffering by calcite dissolution) were simulated. Local and global sensitivity analysis techniques were applied to delineate the dominant model parameters and processes. Sensitivity analysis indicated that accurate values for parameters related to dichloroethene (DCE) and vinyl chloride (VC) degradation (i.e., DCE and VC maximum utilization rates, yield due to DCE utilization, decay rate for DCE/VC dechlorinators) are important for prediction of the overall dechlorination time. These parameters influence the maximum growth rate of the DCE and VC dechlorinating microorganisms and, thus, the time required for a small initial population to reach a sufficient concentration to significantly affect the overall rate of dechlorination. Self-inhibition of chlorinated ethenes at high concentrations and natural buffering provided by the sediment were also shown to significantly influence the dechlorination time. Furthermore, the analysis indicated that the rates of the competing, nonchlorinated electron-accepting processes relative to the dechlorination kinetics also affect the overall dechlorination time. Results demonstrated that the model developed is a flexible research tool that is able to provide valuable insight into the fundamental processes and their complex interactions during bioremediation of chlorinated ethenes in DNAPL source zones.

Molecular dynamics study of polysaccharides in binary solvent mixtures of an ionic liquid and water.

PubMed

Liu, Hanbin; Sale, Kenneth L; Simmons, Blake A; Singh, Seema

2011-09-01

Some ionic liquids (ILs) have great promise as effective solvents for biomass pretreatment, and there are several that have been reported that can dissolve large amounts of cellulose. The solubilized cellulose can then be recovered by addition of antisolvents, such as water or ethanol, and this regeneration process plays an important role in the subsequent enzymatic saccharification reactions and in the recovery of the ionic liquid. To date, little is known about the fundamental intermolecular interactions that drive the dissolution and subsequent regeneration of cellulose in complex mixtures of ionic liquids, water, and cellulose. To investigate these interactions, in this work, molecular dynamics (MD) simulations were carried out to study binary and ternary mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) with water and a cellulose oligomer. Simulations of a cellulose oligomer dissolved in three concentrations of binary mixtures of [C2mim][OAc] and water were used to represent the ternary system in the dissolution phase (high [C2mim][OAc] concentration) and present during the initial phase of the regeneration step (intermediate and low [C2mim][OAc] concentrations). The MD analysis of the structure and dynamics that exist in these binary and ternary mixtures provides information on the key intermolecular interactions between cellulose and [C2mim][OAc] that lead to dissolution of cellulose and the key intermolecular interactions in the intermediate states of cellulose precipitation as a function of water content in the cellulose/IL/water system. The analysis of this intermediate state provides new insight into the molecular driving forces present in this ternary system. © 2011 American Chemical Society

Formulation of poorly water-soluble Gemfibrozil applying power ultrasound.

PubMed

Ambrus, R; Naghipour Amirzadi, N; Aigner, Z; Szabó-Révész, P

2012-03-01

The dissolution properties of a drug and its release from the dosage form have a basic impact on its bioavailability. Solubility problems are a major challenge for the pharmaceutical industry as concerns the development of new pharmaceutical products. Formulation problems may possibly be overcome by modification of particle size and morphology. The application of power ultrasound is a novel possibility in drug formulation. This article reports on solvent diffusion and melt emulsification, as new methods supplemented with drying in the field of sonocrystallization of poorly water-soluble Gemfibrozil. During thermoanalytical characterization, a modified structure was detected. The specific surface area of the drug was increased following particle size reduction and the poor wettability properties could also be improved. The dissolution rate was therefore significantly increased. Copyright © 2011 Elsevier B.V. All rights reserved.

Berberine nanoparticles with enhanced in vitro bioavailability: characterization and antimicrobial activity

PubMed Central

Faidah, Hani S; Khurram, Muhammad; Amin, Muhammad Usman; Haseeb, Abdul; Kakar, Maria

2018-01-01

Background Berberine is an isoquinoline alkaloid widely used in Ayurveda and traditional Chinese medicine to treat illnesses such as hypertension and inflammatory conditions, and as an anticancer and hepato-protective agent. Berberine has low oral bioavailability due to poor aqueous solubility and insufficient dissolution rate, which can reduce the efficacy of drugs taken orally. In this study, evaporative precipitation of nanosuspension (EPN) and anti-solvent precipitation with a syringe pump (APSP) were used to address the problems of solubility, dissolution rate and bioavailability of berberine. Methods Semi-crystalline nanoparticles (NPs) of 90–110 nm diameter for APSP and 65–75 nm diameter for EPN were prepared and then characterized using differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRD). Thereafter, drug content solubility and dissolution studies were undertaken. Berberine and its NPs were evaluated for their antibacterial activity. Results The results indicate that the NPs have significantly increased solubility and dissolution rate due to conversion of the crystalline structure to a semi-crystalline form. Conclusion Berberine NPs produced by both APSP and EPN methods have shown promising activities against Gram-positive and Gram-negative bacteria, and yeasts, with NPs prepared through the EPN method showing superior results compared to those made with the APSP method and the unprocessed drug. PMID:29491706

Spray drying of poorly soluble drugs from aqueous arginine solution.

PubMed

Ojarinta, Rami; Lerminiaux, Louise; Laitinen, Riikka

2017-10-30

Co-amorphous drug-amino acid mixtures have shown potential for improving the solid-state stability and dissolution behavior of amorphous drugs. In previous studies, however these mixtures have been produced mainly with small-scale preparation methods, or with methods that have required the use of organic solvents or other dissolution enhancers. In the present study, co-amorphous ibuprofen-arginine and indomethacin-arginine mixtures were spray dried from water. The mixtures were prepared at two drug-arginine molar ratios (1:1 and 1:2). The properties of the prepared mixtures were investigated with differential scanning calorimetry, X-ray powder diffractometry, Fourier-transform infrared spectroscopy and a 24h, non-sink, dissolution study. All mixtures exhibited a single glass transition temperature (T g ), evidence of the formation of homogenous single-phase systems. Fourier transform infrared spectroscopy revealed strong interactions (mainly salt formation) that account for the positive deviation between measured and estimated T g values. No crystallization was observed during a 1-year stability study in either 1:1 or 1:2 mixtures, but in the presence of moisture, handling difficulties were encountered. The formation of co-amorphous salts led to improved dissolution characteristics when compared to the corresponding physical mixtures or to pure crystalline drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Berberine nanoparticles with enhanced in vitro bioavailability: characterization and antimicrobial activity.

PubMed

Sahibzada, Muhammad Umar Khayam; Sadiq, Abdul; Faidah, Hani S; Khurram, Muhammad; Amin, Muhammad Usman; Haseeb, Abdul; Kakar, Maria

2018-01-01

Berberine is an isoquinoline alkaloid widely used in Ayurveda and traditional Chinese medicine to treat illnesses such as hypertension and inflammatory conditions, and as an anticancer and hepato-protective agent. Berberine has low oral bioavailability due to poor aqueous solubility and insufficient dissolution rate, which can reduce the efficacy of drugs taken orally. In this study, evaporative precipitation of nanosuspension (EPN) and anti-solvent precipitation with a syringe pump (APSP) were used to address the problems of solubility, dissolution rate and bioavailability of berberine. Semi-crystalline nanoparticles (NPs) of 90-110 nm diameter for APSP and 65-75 nm diameter for EPN were prepared and then characterized using differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRD). Thereafter, drug content solubility and dissolution studies were undertaken. Berberine and its NPs were evaluated for their antibacterial activity. The results indicate that the NPs have significantly increased solubility and dissolution rate due to conversion of the crystalline structure to a semi-crystalline form. Berberine NPs produced by both APSP and EPN methods have shown promising activities against Gram-positive and Gram-negative bacteria, and yeasts, with NPs prepared through the EPN method showing superior results compared to those made with the APSP method and the unprocessed drug.

Carbon dioxide adsorption in Brazilian coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jose Luciano Soares; Andre L.B. Oberziner; Humberto J. Jose

Carbon dioxide (CO{sub 2}) is one of the most important greenhouse gases. In the period between 1980 and 1998, CO{sub 2} emissions increased more than 21% and projections suggest that the emissions will continue to increase globally by 2.2% between 2000 and 2020 and 3.3% in the developed countries. The sequestration of CO{sub 2} in deep unminable coal beds is one of the more promising of several methods of geological sequestration that are currently being investigated. CO{sub 2} can adsorb onto coal, and there are several studies demonstrating that CO{sub 2} dissolves in coals and swells them. At very lowmore » pressures (P {lt} 1 bar), CO{sub 2} dissolution does not seem to be a problem; however, high pressures are necessary for CO{sub 2} sequestration (P {gt} 50 bar). In this study, we evaluated the kinetics and equilibrium of sorption of CO{sub 2} on Brazilian coals at low pressures. The adsorption equilibrium isotherm at room temperature (30{sup o}C) was measured through the static method. The results showed that the Freundlich model or the Langmuir model is suitable to describe the equilibrium experimental results. The CO{sub 2} adsorption capacity of Brazilian coals are in the range of 0.089-0.186 mmol CO{sub 2}/g, which are typical values for coals with high ash content. The dynamics of adsorption in a fixed-bed column that contains granular coal (particle sizes of 0.8, 2.4, and 4.8 mm) showed that the adsorption rate is fast and a mathematical model was developed to describe the CO{sub 2} dynamics of the adsorption in a fixed-bed column. The linear driving force (LDF) was used to describe the rate of adsorption and the mass-transfer constants of the LDF model (K{sub s}) are in the range of 1.0-2.0 min{sup -1}. 29 refs., 5 figs., 3 tabs.« less

Experiment on the treatment of waste extraction solvent from the molybdenum-99 process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsien-Ming Hsiao; Chang-Liang Hu; Kuang-Li Chien

2013-07-01

In the Mo-99 (Molybdenum-99) isotope extraction test process for radiopharmaceutical applications, organic solvent is used to extract Mo-99 from an irradiated UO{sub 2} dissolution. The extraction solvent was stored when the test work was stopped. A total of about 120 liters of waste solvent was stored at INER (Institute of Nuclear Energy Research, Taiwan). The extraction solvent consisted of 5% di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and kerosene. The radionuclides found in the waste solvent include Cs-137, Am-241, Tc-99, and Sr-90, which give off gross alpha and beta radioactivity of 1898 and 471 Bq/ml, respectively. This study aims to remove radionuclides from themore » waste solvent using sodium carbonate and sodium hydroxide solutions in different concentrations. After mixing the waste solvent with the alkaline solution followed by settling, a third phase other than organic and aqueous phase appeared which is expected due to the saponification reaction. The experimental results showed that increasing the number of washing and the alkaline solution concentration could enhance the radionuclides removal rate. An optimal removal method was proposed using 2 M Na{sub 2}CO{sub 3} solution twice followed by 1 M NaOH solution one time for the third phase generated early in the mixing stages. The remaining gross alpha and beta radioactivity of the treated organic solvent was 2 and 3 Bq/ml, respectively. The treated solvent could be stabilized by ashing at 500 deg. C and then immobilized. The alkaline solution would be neutralized by hydrochloric or nitric acid and then treated using a variety of adsorbents or bone char via adsorption to remove nuclides to meet the wastewater discharge limitation. (authors)« less

Coal Producer's Rubber Waste Processing Development

NASA Astrophysics Data System (ADS)

Makarevich, Evgeniya; Papin, Andrey; Nevedrov, Alexander; Cherkasova, Tatyana; Ignatova, Alla

2017-11-01

A large amount of rubber-containing waste, the bulk of which are worn automobile tires and conveyor belts, is produced at coal mining and coal processing enterprises using automobile tires, conveyor belts, etc. The volume of waste generated increases every year and reaches enormous proportions. The methods for processing rubber waste can be divided into three categories: grinding, pyrolysis (high and low temperature), and decomposition by means of chemical solvents. One of the known techniques of processing the worn-out tires is their regeneration, aimed at producing the new rubber substitute used in the production of rubber goods. However, the number of worn tires used for the production of regenerate does not exceed 20% of their total quantity. The new method for processing rubber waste through the pyrolysis process is considered in this article. Experimental data on the upgrading of the carbon residue of pyrolysis by the methods of heavy media separation, magnetic and vibroseparation, and thermal processing are presented.

Effects of Anion Mobility on Electrochemical Behaviors of Lithium–Sulfur Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Kee Sung; Chen, Junzheng; Cao, Ruiguo

The electrolyte is a crucial component of lithium-sulfur (Li-S) batteries, as it controls polysulfide dissolution, charge shuttling processes, and solid-electrolyte interphase (SEI) layer formation. Experimentally, the overall performance of Li-S batteries varies with choice of solvent system and Li-salt used in the electrolyte, and a lack of predictive understanding about the effects of individual electrolyte components inhibits the rational design of electrolytes for Li-S batteries. Here we analyze the role of the counter anions of common Li salts (such as TfO-, FSI-, TFSI-, and TDI-) when dissolved in DOL/DME (1:1 vol.) for use in Li-S batteries. The evolution of ion-ionmore » and ion-solvent interactions due to vari-ous anions was analyzed using 17O NMR and pulsed-field gradient (PFG) NMR and then correlated with electrochemi-cal performance in Li-S cells. These data reveal that the for-mation of the passivation layer on the anode and the loss of active materials from the cathode (evidenced by polysulfide dissolution) are related to anion mobility and affinity with lithium polysulfide, respectively. For future electrolyte de-sign, anions with lower mobility and weaker interactions with lithium polysulfides may be superior candidates for increasing the long-term stability of Li-S batteries.« less

Application of dense gas techniques for the production of fine particles.

PubMed

Foster, Neil R; Dehghani, Fariba; Charoenchaitrakoo, Kiang M; Warwick, Barry

2003-01-01

The feasibility of using dense gas techniques such as rapid expansion of supercritical solutions (RESS) and aerosol solvent extraction system (ASES) for micronization of pharmaceutical compounds is demonstrated. The chiral nonsteroidal anti-inflammatory racemic ibuprofen is soluble in carbon dioxide at 35 degrees C and pressures above 90 bar. The particle size decreased to less than 2 microm while the degree of crystallinity was slightly decreased when processed by RESS. The dissolution rate of the ibuprofen (a poorly water-soluble compound) was significantly enhanced after processing by RESS. The nonsteroidal anti-inflammatory drug Cu2(indomethacin)4L2(Cu-Indo); (L = dimethylformamide [DMF]), which possessed very low solubility in supercritical CO2, was successfully micronized by ASES at 25 degrees C and 68.9 bar using DMF as the solvent and CO2 as the antisolvent. The concentration of solute dramatically influenced the precipitate characteristics. The particles obtained from the ASES process were changed from bipyramidal to spherical, with particle size less than 5 microm, as the concentration increased from 5 to 100 mg/g. A further increase in solute concentration to 200 mg/g resulted in large porous spheres, between 20 and 50 micron, when processing Cu-Indo by the ASES method. The dissolution rate of the micronized Cu-Indo was significantly higher than the commercial product.

Evaluation of SLS: APG mixed surfactant systems as carrier for solid dispersion.

PubMed

Patel, Ashok R; Joshi, Vishal Y

2008-01-01

The present investigation aims at studying the effect of mixed surfactant system of sodium lauryl sulphate (SLS) and alkyl polyglucosides (C(10)APG, C(12)APG and C(12/14)APG) on dissolution rate enhancement of poorly water soluble drug. Aceclofenac--a non-steroidal anti-inflammatory agent was used as a model drug as it has limited water solubility. The influence of the surfactant concentration in various blends on dissolution rate of Solid Dispersion (SD), prepared using solution method with ethanol as the solvent was studied and the advantage of mixed surfactant systems over the individual surfactants was illustrated by differences in the in-vitro dissolution profiles of SD. Physico chemical evaluation (critical micellar concentration, zeta potential and beta-parameter calculations) was carried out to study the mixed surfactant systems. Solid mixtures were characterized by Infrared spectroscopy (FT-IR); X-ray diffraction studies (XRD) and scanning electron microscopy (SEM). It was seen that the dissolution rate of aceclofenac from SD increased with the increase in the APG proportion relative to SLS with the optimum ratio of 0.2 SLS:0.8 APG showing the best effect in all cases. Results obtained from physico-chemical evaluation (the decrease in the value of critical micelle concentration and higher negative value of beta-parameters) suggested the existence of synergism between surfactants blends. The observed results in the dissolution rate enhancement could be attributed to the drug--surfactant interactions as evident from FT-IR, SEM and XRD results.

Evaluation of various processes for simultaneous complexation and granulation to incorporate drug-cyclodextrin complexes into solid dosage forms.

PubMed

Gyanani, Vijay; Siddalingappa, Basavaraj; Betageri, Guru V

2015-01-01

Insoluble drugs often formulated with various excipients to enhance the dissolution. Cyclodextrins (CDs) are widely used excipients to improve dissolution profile of poorly soluble drugs. Drug-CD complexation process is complex and often requires multiple processes to produce solid dosage form. Hence, this study explored commonly used granulation processes for simultaneous complexation and granulation. Poorly soluble drugs ibuprofen and glyburide were selected as experimental drugs. Co-evaporation of drug:CD mixture from a solvent followed by wet granulation with water was considered as standard process for comparison. Spray granulation and fluid bed processing (FBP) using drug:CD solution in ethanol were evaluated as an alternative processes. The dissolution data of glyburide tablets indicated that tablets produced by spray granulation, FBP and co-evaporation-granulation have almost identical dissolution profile in water and 0.1% SLS (>70% in water and >60% in SLS versus 30 and 34%, respectively for plain tablet, in 120 min). Similarly, ibuprofen:CD tablets produced by co-evaporation-granulation and FBP displayed similar dissolution profile in 0.01 M HCl (pH 2.0) and buffer pH 5.5 (>90 and 100% versus 44 and 80% respectively for plain tablets, 120 min). Results of this study demonstrated that spray granulation is simple and cost effective process for low dose poorly soluble drugs to incorporate drug:CD complex into solid dosage form, whereas FBP is suitable for poorly soluble drugs with moderate dose.

Polycyclic aromatic hydrocarbons (PAHs) from coal combustion: emissions, analysis, and toxicology.

PubMed

Liu, Guijian; Niu, Zhiyuan; Van Niekerk, Daniel; Xue, Jian; Zheng, Liugen

2008-01-01

Coal may become more important as an energy source in the 21st century, and coal contains large quantities of organic and inorganic matter. When coal burns chemical and physical changes take place, and many toxic compounds are formed and emitted. Polycyclic aromatic hydrocarbons (PAHs) are among those compounds formed and are considered to pose potential health hazards because some PAHs are known carcinogens. Based on their toxicology, 16 PAHs are considered as priority pollutants by the USEPA. More attention must be given to the various methods of extraction and analysis of PAH from coal or coal products to accurately explain and determine the species of PAHs. The influences of the extraction time, solvents, and methods for PAH identification are important. In the future, more methods and influences will be studied more carefully and widely. PAHs are environmental pollutants, are highly lipid soluble, and can be absorbed by the lungs, gut, and skin of mammals because they are associated with fine particles from coal combustion. More attention is being given to PAHs because of their carcinogenic and mutagenic action. We suggest that when using a coal stove indoors, a chimney should be used; the particles and gas containing PAHs should be released outdoors to reduce the health hazard, especially in Southwest China. During coal utilization processes, such as coal combustion and pyrolysis, PAHs released may be divided into two categories according to their formation pathways: one pathway is derived from complex chemical reactions and the other is from free PAHs transferred from the original coal. The formation and emission of PAHs is a complex physical and chemical process that has received considerable attention in recent years. It is suggested that the formation mechanisms of PAHs will be an increasingly important topic for researchers to find methods for controlling emissions during coal combustion.

Interaction of planar and nonplanar organic contaminants with coal fly ash: effects of polar and nonpolar solvent solutions.

PubMed

Burgess, Robert M; Ryba, Stephan A; Cantwell, Mark G; Gundersen, Jennifer L; Tien, Rex; Perron, Monique M

2006-08-01

Coal fly ash has a very high sorption capacity for a variety of anthropogenic contaminants and has been used to cleanse wastewater of pollutants for approximately 40 years. Like other black carbons, the planar structure of the residual carbon in fly ash results in elevated affinities for planar organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and some polychlorinated biphenyls (PCBs). The present study was performed to understand better the mechanisms affecting the strong interaction between planar contaminants and coal fly ash. The removal of 10 PCBs and 10 PAHs by several fly ashes and other sorbents was evaluated under different experimental conditions to highlight the intermolecular forces influencing adsorption. Varying fly ash concentration and solvent system composition indicated that dispersive interactions were most prevalent. For the PCBs, empirical results also were compared to molecular modeling estimates of the energy necessary for the PCB molecule to assume a planar conformation (PCe). The PCe levels ranged from 8 to 25 kcal/mol, depending on the degree of ortho-substituted chlorination of the PCB. A significant correlation between PCe and PCB removal from solution was observed for the fly ashes and activated carbon, whereas the nonplanar sorbent octadecyl (C18) indicated no relationship. These findings demonstrate the strong interaction between black carbon fly ash and planar organic contaminants. Furthermore, as exemplified by the PCBs, these results show how this interaction is a function of a contaminant's ability to assume a planar conformation.

Production of Catalyst-Free Hyperpolarised Ethanol Aqueous Solution via Heterogeneous Hydrogenation with Parahydrogen

NASA Astrophysics Data System (ADS)

Salnikov, Oleg G.; Kovtunov, Kirill V.; Koptyug, Igor V.

2015-09-01

An experimental approach for the production of catalyst-free hyperpolarised ethanol solution in water via heterogeneous hydrogenation of vinyl acetate with parahydrogen and the subsequent hydrolysis of ethyl acetate was demonstrated. For an efficient hydrogenation, liquid vinyl acetate was transferred to the gas phase by parahydrogen bubbling and almost completely converted to ethyl acetate with Rh/TiO2 catalyst. Subsequent dissolution of ethyl acetate gas in water containing OH- ions led to the formation of catalyst- and organic solvent-free hyperpolarised ethanol and sodium acetate. These results represent the first demonstration of catalyst- and organic solvent-free hyperpolarised ethanol production achieved by heterogeneous hydrogenation of vinyl acetate vapour with parahydrogen and the subsequent ethyl acetate hydrolysis.

Production of Catalyst-Free Hyperpolarised Ethanol Aqueous Solution via Heterogeneous Hydrogenation with Parahydrogen.

PubMed

Salnikov, Oleg G; Kovtunov, Kirill V; Koptyug, Igor V

2015-09-09

An experimental approach for the production of catalyst-free hyperpolarised ethanol solution in water via heterogeneous hydrogenation of vinyl acetate with parahydrogen and the subsequent hydrolysis of ethyl acetate was demonstrated. For an efficient hydrogenation, liquid vinyl acetate was transferred to the gas phase by parahydrogen bubbling and almost completely converted to ethyl acetate with Rh/TiO2 catalyst. Subsequent dissolution of ethyl acetate gas in water containing OH(-) ions led to the formation of catalyst- and organic solvent-free hyperpolarised ethanol and sodium acetate. These results represent the first demonstration of catalyst- and organic solvent-free hyperpolarised ethanol production achieved by heterogeneous hydrogenation of vinyl acetate vapour with parahydrogen and the subsequent ethyl acetate hydrolysis.

Coal technology program progress report, February 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Final testing of the 20-atm bench-scale system is underway in preparation for experiments with hydrogen. Laboratory-scale testing of a number of inexpensive pure compounds to improve the settling rate of solids in Solvent Refined Coal (SRC) unfiltered oil (UFO), bench-scale testing of the effect of the Tretolite additive on settling, and characterization tests on a new sample of UFO from the PAMCO-SRC process are reported. Experimental engineering support of an in situ gasification process include low-temperature pyrolyses at exceptionally low heating rates (0.3/sup 0/C/min). Highly pyrophoric chars were consistently produced. Aqueous by-products from coal conversion technologies and oil shale retortingmore » have been analyzed directly to determine major organic components. A report is being prepared discussing various aspects of the engineering evaluations of nuclear process heat for coal. A bench-scale test program on thermochemical water splitting for hydrogen production is under consideration. In the coal-fueled MIUS program, preparations for procurement of tubing for the matrix in the fluidized-bed furnace and for fabrication of the furnace continued. Analyses of the AiResearch gas turbine and recuperator under coal-fueled MIUS operating conditions are near completion. Process flow diagrams and heat and material balances were completed for most of the units in the synthoil process. Overall utilities requirements were calculated and the coal preparation flowsheets were finalized. For hydrocarbonization, the flowsheet was revised to include additional coal data. Flowsheets were finalized for the acid gas separation and recycle, and the oil-solids separation. (LTN)« less

27 CFR 21.65 - Formula No. 38-B.

Code of Federal Regulations, 2012 CFR

2012-04-01

.... Cinnamic aldehyde, N.F. IX. Cinnamon oil, N.F. Citronella oil, natural. Clove oil, N.F. Coal tar, U.S.P..., terpeneless. Spike lavender oil, natural. Storax, U.S.P. Thyme oil, N.F. XII. Thymol, N.F. Tolu balsam, U.S.P... the denaturant for analysis. (b) Authorized uses. (1) As a solvent: 111.Hair and scalp preparations...

27 CFR 21.65 - Formula No. 38-B.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... Cinnamic aldehyde, N.F. IX. Cinnamon oil, N.F. Citronella oil, natural. Clove oil, N.F. Coal tar, U.S.P..., terpeneless. Spike lavender oil, natural. Storax, U.S.P. Thyme oil, N.F. XII. Thymol, N.F. Tolu balsam, U.S.P... the denaturant for analysis. (b) Authorized uses. (1) As a solvent: 111.Hair and scalp preparations...

27 CFR 21.65 - Formula No. 38-B.

Code of Federal Regulations, 2013 CFR

2013-04-01

.... Cinnamic aldehyde, N.F. IX. Cinnamon oil, N.F. Citronella oil, natural. Clove oil, N.F. Coal tar, U.S.P..., terpeneless. Spike lavender oil, natural. Storax, U.S.P. Thyme oil, N.F. XII. Thymol, N.F. Tolu balsam, U.S.P... the denaturant for analysis. (b) Authorized uses. (1) As a solvent: 111.Hair and scalp preparations...

27 CFR 21.65 - Formula No. 38-B.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... Cinnamic aldehyde, N.F. IX. Cinnamon oil, N.F. Citronella oil, natural. Clove oil, N.F. Coal tar, U.S.P..., terpeneless. Spike lavender oil, natural. Storax, U.S.P. Thyme oil, N.F. XII. Thymol, N.F. Tolu balsam, U.S.P... the denaturant for analysis. (b) Authorized uses. (1) As a solvent: 111.Hair and scalp preparations...

27 CFR 21.65 - Formula No. 38-B.

Code of Federal Regulations, 2014 CFR

2014-04-01

.... Cinnamic aldehyde, N.F. IX. Cinnamon oil, N.F. Citronella oil, natural. Clove oil, N.F. Coal tar, U.S.P..., terpeneless. Spike lavender oil, natural. Storax, U.S.P. Thyme oil, N.F. XII. Thymol, N.F. Tolu balsam, U.S.P... the denaturant for analysis. (b) Authorized uses. (1) As a solvent: 111.Hair and scalp preparations...

Catalytic two-stage coal hydrogenation process using extinction recycle of heavy liquid fraction

DOEpatents

MacArthur, J.B.; Comolli, A.G.; McLean, J.B.

1989-10-17

A process is described for catalytic two-stage hydrogenation and liquefaction of coal with selective extinction recycle of all heavy liquid fractions boiling above a distillation cut point of about 600--750 F to produce increased yields of low-boiling hydrocarbon liquid and gas products. In the process, the particulate coal feed is slurried with a process-derived liquid solvent normally boiling above about 650 F and fed into a first stage catalytic reaction zone operated at conditions which promote controlled rate liquefaction of the coal, while simultaneously hydrogenating the hydrocarbon recycle oils. The first stage reactor is maintained at 710--800 F temperature, 1,000--4,000 psig hydrogen partial pressure, and 10-90 lb/hr per ft[sup 3] catalyst space velocity. Partially hydrogenated material withdrawn from the first stage reaction zone is passed directly to the second stage catalytic reaction zone maintained at 760--860 F temperature for further hydrogenation and hydroconversion reactions. A 600--750 F[sup +] fraction containing 0--20 W % unreacted coal and ash solids is recycled to the coal slurrying step. If desired, the cut point lower boiling fraction can be further catalytically hydrotreated. By this process, the coal feed is successively catalytically hydrogenated and hydroconverted at selected conditions, to provide significantly increased yields of desirable low-boiling hydrocarbon liquid products and minimal production of hydrocarbon gases, and no net production of undesirable heavy oils and residuum materials. 2 figs.

Catalytic two-stage coal hydrogenation process using extinction recycle of heavy liquid fraction

DOEpatents

MacArthur, James B.; Comolli, Alfred G.; McLean, Joseph B.

1989-01-01

A process for catalytic two-stage hydrogenation and liquefaction of coal with selective extinction recycle of all heavy liquid fractions boiling above a distillation cut point of about 600.degree.-750.degree. F. to produce increased yields of low-boiling hydrocarbon liquid and gas products. In the process, the particulate coal feed is slurried with a process-derived liquid solvent normally boiling above about 650.degree. F. and fed into a first stage catalytic reaction zone operated at conditions which promote controlled rate liquefaction of the coal, while simultaneously hydrogenating the hydrocarbon recycle oils. The first stage reactor is maintained at 710.degree.-800.degree. F. temperature, 1000-4000 psig hydrogen partial pressure, and 10-90 lb/hr per ft.sup.3 catalyst space velocity. Partially hydrogenated material withdrawn from the first stage reaction zone is passed directly to the second stage catalytic reaction zone maintained at 760.degree.-860.degree. F. temperature for further hydrogenation and hydroconversion reactions. A 600.degree.-750.degree. F..sup.+ fraction containing 0-20 W % unreacted coal and ash solids is recycled to the coal slurrying step. If desired, the cut point lower boiling fraction can be further catalytically hydrotreated. By this process, the coal feed is successively catalytically hydrogenated and hydroconverted at selected conditions, to provide significantly increased yields of desirable low-boiling hydrocarbon liquid products and minimal production of hydrocarbon gases, and no net production of undesirable heavy oils and residuum materials.

A multi-instrumental geochemical study of anomalous uranium enrichment in coal.

PubMed

Havelcová, Martina; Machovič, Vladimír; Mizera, Jiří; Sýkorová, Ivana; Borecká, Lenka; Kopecký, Lubomír

2014-11-01

Contents of uranium in coals from Odeř in the northernmost part of the Sokolov Basin, Czech Republic, in the vicinity of the well known St. Joachimsthal uranium ore deposits, reach extremely high values. In the present work, coal samples with contents of uranium ranging from 0.02 to 6 wt.% were studied. The study employing a whole complex of analytical techniques has been aimed at identification of changes in the structure of coal organic matter, which are associated with the high contents of uranium in coal. The study includes proximate and ultimate analyses, multielement analysis by instrumental neutron and photon activation analyses, micropetrographic analysis by optical microscopy, ESEM/EDX analysis of mineral matter, infrared and Raman spectroscopies, solvent extraction followed by gas chromatography with mass spectroscopy (GC/MS), and analytical pyrolysis (Py-GC/MS). The study has confirmed previously proposed explanation of uraniferous mineralization in sedimentary carboniferous substances by the mechanism of reduction and fixation of soluble U(VI) (uranyl, UO2(2+)) species (e.g., humic, carbonate/hydroxo/phosphate complexes) by sedimentary organic matter under diagenetic or hydrothermal conditions, and formation of insoluble U(IV) species as phosphate minerals and uraninite. The process is accompanied with alteration and destruction of the coal organic matter. The changes in the structure of coal organic matter involve dehydrogenation and oxidation mainly in the aliphatic, aromatic and hydroxyl structures, and an increase in aromaticity, content of ether bonds, and the degree of coalification. Copyright © 2014 Elsevier Ltd. All rights reserved.

Aromatized arborane/fernane hydrocarbons as biomarkers for cordaites

NASA Astrophysics Data System (ADS)

Auras, Stefan; Wilde, Volker; Scheffler, Kay; Hoernes, Stephan; Kerp, Hans; Püttmann, Wilhelm

2006-12-01

Previous palaeobotanical and palynological studies on coals from Euramerican Pennsylvanian (≡ Late Carboniferous) coal basins indicate a major change in coal-swamp floras, especially at the Westphalian Stephanian (≈Kasimovian Gzhelian, according to Geological Time Scale 2004) boundary. A flora dominated by arborescent lycophytes was replaced by a vegetation dominated by marattialean tree ferns in various Euramerican coal basins. Earlier combined palynological and organic geochemical studies on Westphalian/Stephanian coals and shales from the Saar-Nahe Basin (Germany) revealed that the distribution of aromatized arborane/fernane hydrocarbons in solvent extracts reflects the increasing importance of seed plants, especially cordaites (extinct group of gymnosperms), conifers and pteridosperms. However, the biological source of the precursor molecules could not be specified. To clarify if the arborane/fernane derivatives MATH, MAPH, DAPH 1, and DAPH 2 in Westphalian/Stephanian coals can be assigned to one of the three potential source plant groups, we analyzed coals, sediments and fossil plant remains from different Euramerican locations with respect to their biomarker composition and stable carbon isotopic composition. Thereby, stable carbon isotopic ratios showed only insignificant variations between Westphalian and Stephanian samples and proved to be an unsuitable tool to describe floral changes during the Westphalian/Stephanian of the Saar-Nahe Basin. In contrast, we were able to show for the first time that MATH, MAPH, DAPH 1 and DAPH 2 are prominent constituents only in extracts of cordaitean macrofossils and can therefore be regarded as biomarkers for this group of gymnosperms.