Organic-Solvent-Free Phase-Transfer Oxidation of Alcohols Using Hydrogen Peroxide

NASA Astrophysics Data System (ADS)

Hulce, Martin; Marks, David W.

2001-01-01

Organic-solvent-free oxidations of alcohols using aqueous hydrogen peroxide in the presence of sodium tungstate and phase-transfer catalysts provide a general, safe, simple, and cost-effective means to prepare ketones. Six representative alcohols, 1-phenylethanol, 1-phenylpropanol, benzhydrol, 4-methylbenzhydrol, cis,trans-4-tert-butylcyclohexanol, and benzyl alcohol are oxidized to the corresponding aldehyde or ketone over 1-3 hours in 81-99% yields. Purities are very high, with only small to trace amounts of starting alcohol remaining. Experiments can be readily designed for one or two 3-hour laboratory periods, integrating the various techniques of extraction, drying, filtration, column chromatography, gas chromatography, NMR and IR spectroscopy, and reaction kinetics.

What factors control dimerization of coniferyl alcohol?

Treesearch

Carl J. Houtman

1999-01-01

Data suggest that the dimerization of coniferyl alcohol is not under thermodynamic control. In this study, molecular dynamics calculations were used to estimate the effect of the solvent environment. In water, the coniferyl alcohol radicals were forced to associate by the formation of a solvent cage. In glycerol, the solvent cage effect appeared to be absent. These...

Freeze-drying of tert-butyl alcohol/water cosolvent systems: effects of formulation and process variables on residual solvents.

PubMed

Wittaya-Areekul, S; Nail, S L

1998-04-01

The objective of this study was to identify significant formulation and processing variables affecting levels of tert-butyl alcohol (TBA) and isopropyl alcohol (IPA) in freeze-dried solids prepared from TBA/water cosolvent systems. The variables examined were the physical state of the solute (crystalline vs amorphous), initial TBA concentration, freezing rate, cake thickness, and the temperature and duration of secondary drying. Sucrose and glycine were used as models for noncrystallizing and crystallizing solutes, respectively. The TBA concentration above which eutectic crystallization takes place was determined by differential scanning calorimetry. Model formulations were subjected to extremes of freezing rate by either dipping in liquid nitrogen or by slowly freezing on the shelf of a freeze-dryer. Dynamics of solvent loss during secondary drying was determined by withdrawing samples as a function of time at different shelf temperatures using a thief system. On the basis of these studies, the most important determinant of residual TBA level is the physical state of the solute. Freeze-dried glycine contained very low levels of residual TBA (0.01-0.03%) regardless of freezing rate or initial TBA concentration. For freeze-dried sucrose, residual TBA levels were approximately 2 orders of magnitude higher and were significantly affected by initial TBA concentration and freezing rate. For the sucrose/TBA/water system, relatively low residual TBA levels were obtained when the initial TBA level was above the threshold concentration for eutectic crystallization of TBA, whereas samples freeze-dried from solutions containing TBA concentrations below this threshold contained significantly higher levels of TBA. Residual IPA levels increased continuously with initial concentration of TBA in the sucrose/TBA/water system. Formulations of sucrose/TBA/water which were frozen rapidly contained residual TBA levels which were approximately twice those measured in the same

Water as a Solvent for Life

NASA Technical Reports Server (NTRS)

Pohorille, Andrew; Pratt, Lawrence R.

2015-01-01

"Follow the water" is our basic strategy in searching for life in the universe. The universality of water as the solvent for living systems is usually justified by arguing that water supports the rich organic chemistry that seeds life, but alternative chemistries are possible in other organic solvents. Here, other, essential criteria for life that have not been sufficiently considered so far, will be discussed.

Solvent-free catalytic dehydrative etherification of benzyl alcohol over graphene oxide

NASA Astrophysics Data System (ADS)

Yu, Huiyou; Wang, Xinde; Zhu, Yuanshuai; Zhuang, Guilin; Zhong, Xing; Wang, Jian-guo

2013-09-01

Graphene oxide (GO), prepared from oxidation of graphite powders using a modified Hummers method, exhibits a promising catalytic activity and a high selectivity for the solvent-free catalytic dehydrative etherification of benzyl alcohol (BA). A maximum yield (85.4%) of dibenzyl ether (DE) was achieved at 150 °C for 24 h when the BA/GO ration was 20 ml/g under solvent-free condition. This discovery provided a new insight into the development of GO as a carbocatalysts for a variety of applications in carbocatalysis.

Conformation Analysis of T1 Lipase on Alcohols Solvent using Molecular Dynamics Simulation

NASA Astrophysics Data System (ADS)

Putri, A. M.; Sumaryada, T.; Wahyudi, S. T.

2017-07-01

Biodiesel usually is produced commercially via a transesterification reaction of vegetable oil with alcohol and alkali catalyst. The alkali catalyst has some drawbacks, such as the soap formation during the reaction. T1 Lipase enzyme had been known as a thermostable biocatalyst which is able to produce biodiesel through a cleaner process. In this paper the performance of T1 lipase enzyme as catalyst for transesterification reaction in pure ethanol, methanol, and water solvents were studied using a Molecular Dynamics (MD) Simulation at temperature of 300 K for 10 nanoseconds. The results have shown that in general the conformation of T1 lipase enzyme in methanol is more dynamics as shown by the value of root mean square deviation (RMSD), root mean squared fluctuation (RMSF), and radius of gyration. The highest solvent accessible surface area (SASA) total was also found in methanol due to the contribution of non-polar amino acid in the interior of the protein. Analysis of MD simulation has also revealed that the enzyme structure tend to be more rigid in ethanol environment. The analysis of electrostatic interactions have shown that Glu359-Arg270 salt-bridge pair might hold the key of thermostability of T1 lipase enzyme as shown by its strong and stable binding in all three solvents.

Pseudolatex preparation using a novel emulsion-diffusion process involving direct displacement of partially water-miscible solvents by distillation.

PubMed

Quintanar-Guerrero, D; Allémann, E; Fessi, H; Doelker, E

1999-10-25

Pseudolatexes were obtained by a new process based on an emulsification-diffusion technique involving partially water-miscible solvents. The preparation method consisted of emulsifying an organic solution of polymer (saturated with water) in an aqueous solution of a stabilizing agent (saturated with solvent) using conventional stirrers, followed by direct solvent distillation. The technique relies on the rapid displacement of the solvent from the internal into the external phase which thereby provokes polymer aggregation. Nanoparticle formation is believed to occur because rapid solvent diffusion produces regions of local supersaturation near the interface, and nanoparticles are formed due to the ensuing interfacial phase transformations and polymer aggregation that occur in these interfacial domains. Using this method, it was possible to prepare pseudolatexes of biodegradable and non-biodegradable polymers such as poly(D,L-lactic acid) and poly(epsilon-caprolactone), Eudragit E, cellulose acetate phthalate, cellulose acetate trimellitate using ethyl acetate or 2-butanone as partially water-miscible solvents and poly(vinyl alcohol) or poloxamer 407 as stabilizing agent. A transition from nano- to microparticles was observed at high polymer concentrations. At concentrations above 30% w/v of Eudragit E in ethyl acetate or cellulose acetate phthalate in 2-butanone only microparticles were obtained. This behaviour was attributed to decreased transport of polymer molecules into the aqueous phase.

SOLVENT-FREE TETRAHYDROPYRANYLATION (THP) OF ALCOHOLS AND PHENOLS AND THEIR REGENERATION BY CATALYTIC ALUMINUM CHLORIDE HEXAHYDRATE

EPA Science Inventory

Catalytic amount of aluminum chloride hexahydrate enables solvent-free tetrahydropyranylation (THP) of alcohols and phenols at moderate temperatures. A simple addition of methanol helps to regenerate the corresponding alcohols and phenols thus rendering these protection and depro...

Separation and concentration of lower alcohols from dilute aqueous solutions

DOEpatents

Moore, Raymond H.; Eakin, David E.; Baker, Eddie G.; Hallen, Richard T.

1991-01-01

A process for producing, from a dilute aqueous solution of a lower (C.sub.1 -C.sub.5) alcohol, a concentrated liquid solution of the alcohol in an aromatic organic solvent is disclosed. Most of the water is removed from the dilute aqueous solution of alcohol by chilling sufficiently to form ice crystals. Simultaneously, the remaining liquid is extracted at substantially the same low temperature with a liquid organic solvent that is substantially immiscible in aqueous liquids and has an affinity for the alcohol at that temperature, causing the alcohol to transfer to the organic phase. After separating the organic liquid from the ice crystals, the organic liquid can be distilled to enrich the concentration of alcohol therein. Ethanol so separated from water and concentrated in an organic solvent such as toluene is useful as an anti-knock additive for gasoline.

Solvent free oxidation of primary alcohols and diols using thymine iron(III) catalyst.

PubMed

Al-Hunaiti, Afnan; Niemi, Teemu; Sibaouih, Ahlam; Pihko, Petri; Leskelä, Markku; Repo, Timo

2010-12-28

In this study, we developed an efficient and selective iron-based catalyst system for the synthesis of ketones from secondary alcohols and carboxylic acids from primary alcohol. In situ generated iron catalyst of thymine-1-acetate (THA) and FeCl(3) under solvent-free condition exhibits high activity. As an example, 1-octanol and 2-octanol were oxidized to 1-octanoic acid and 2-octanone with 89% and 98% yields respectively.

Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Hie, Liana; Chang, Jonah J.; Garg, Neil K.

2015-01-01

A modern undergraduate organic chemistry laboratory experiment involving the Suzuki-Miyaura coupling is reported. Although Suzuki-Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a "green" alcohol solvent. The…

Thin PDMS Films Using Long Spin Times or Tert-Butyl Alcohol as a Solvent

PubMed Central

Koschwanez, John H.; Carlson, Robert H.; Meldrum, Deirdre R.

2009-01-01

Thin polydimethylsiloxane (PDMS) films are frequently used in “lab on a chip” devices as flexible membranes. The common solvent used to dilute the PDMS for thin films is hexane, but hexane can swell the underlying PDMS substrate. A better solvent would be one that dissolves uncured PDMS but doesn't swell the underlying substrate. Here, we present protocols and spin curves for two alternatives to hexane dilution: longer spin times and dilution in tert-butyl alcohol. The thickness of the PDMS membranes under different spin speeds, spin times, and PDMS concentrations was measured using an optical profilometer. The use of tert-butyl alcohol to spin thin PDMS films does not swell the underlying PDMS substrate, and we have used these films to construct multilayer PDMS devices. PMID:19238212

Switchable solvents and methods of use thereof

DOEpatents

Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

2013-08-20

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Switchable solvents and methods of use thereof

DOEpatents

Jessop, Philip G [Kingston, CA; Eckert, Charles A [Atlanta, GA; Liotta, Charles L [Atlanta, GA; Heldebrant, David J [Richland, WA

2011-07-19

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Switchable solvents and methods of use thereof

DOEpatents

Jessop, Philip G; Eckert, Charles A; Liotta, Charles L; Heldebrant, David J

2014-04-29

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Recovery of isopropyl alcohol from waste solvent of a semiconductor plant.

PubMed

Lin, Sheng H; Wang, Chuen S

2004-01-30

An important waste solvent generated in the semiconductor manufacturing process was characterized by high isopropyl alcohol (IPA) concentration over 65%, other organic pollutants and strong color. Because of these characteristics, IPA recovery was deemed as a logic choice for tackling this waste solvent. In the present work, an integrated method consisting of air stripping in conjunction with condensation and packed activated carbon fiber (ACF) adsorption for dealing with this waste solvent. The air stripping with proper stripping temperature control was employed to remove IPA from the waste solvent and the IPA vapor in the gas mixture was condensed out in a side condenser. The residual IPA remaining in the gas mixture exiting the side condenser was efficiently removed in a packed ACF column. The air stripping with condensation was able to recover up to 93% of total IPA in the initial waste solvent. The residual IPA in the gas mixture, representing less than 3% of the initial IPA, was efficiently captured in the packed ACF column. Experimental tests were conducted to examine the performances of each unit and to identify the optimum operating conditions. Theoretical modeling of the experimental IPA breakthrough curves was also undertaken using a macroscopic model. The verified breakthrough model significantly facilitates the adsorption column design. The recovered IPA was found to be of high purity and could be considered for reuse. Copyright 2003 Elsevier B.V.

27 CFR 21.125 - Rubber hydrocarbon solvent.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative. (b...

27 CFR 21.125 - Rubber hydrocarbon solvent.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative. (b...

Probing the interaction of 1-ethyl-3-methylimidazolium ethyl sulfate ([Emim][EtSO4]) with alcohols and water by solvent and rotational relaxation.

PubMed

Sarkar, Souravi; Pramanik, Rajib; Ghatak, Chiranjib; Setua, Palash; Sarkar, Nilmoni

2010-03-04

The effect of the addition of cosolvents in the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethyl sulfate ([Emim][EtSO(4)]) was probed by the solvent and rotational relaxation studies of coumarin 153 in neat ionic liquid [Emim][EtSO(4)] and [Emim][EtSO(4)]-cosolvent mixtures by using steady-state and time-resolved fluorescence spectroscopy. With gradual addition of cosolvents in the RTIL, both the average solvation time and rotational relaxation times gradually decrease. Addition of cosolvents in the IL decreases the viscosity of the medium. We have optimized the geometry of [Emim][EtSO(4)] and [Emim][EtSO(4)]-cosolvent mixtures by using quantum chemical calculations using density functional theory methods, which show the formation of hydrogen bond between cosolvents with [Emim][EtSO(4)]. With addition of the same amount of alcohols in neat [Emim][EtSO(4)], the rotational relaxation time decreases more compared to the addition of the same amount of water.

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.

Essential roles of protein-solvent many-body correlation in solvent-entropy effect on protein folding and denaturation: comparison between hard-sphere solvent and water.

PubMed

Oshima, Hiraku; Kinoshita, Masahiro

2015-04-14

In earlier works, we showed that the entropic effect originating from the translational displacement of water molecules plays the pivotal role in protein folding and denaturation. The two different solvent models, hard-sphere solvent and model water, were employed in theoretical methods wherein the entropic effect was treated as an essential factor. However, there were similarities and differences in the results obtained from the two solvent models. In the present work, to unveil the physical origins of the similarities and differences, we simultaneously consider structural transition, cold denaturation, and pressure denaturation for the same protein by employing the two solvent models and considering three different thermodynamic states for each solvent model. The solvent-entropy change upon protein folding/unfolding is decomposed into the protein-solvent pair (PA) and many-body (MB) correlation components using the integral equation theories. Each component is further decomposed into the excluded-volume (EV) and solvent-accessible surface (SAS) terms by applying the morphometric approach. The four physically insightful constituents, (PA, EV), (PA, SAS), (MB, EV), and (MB, SAS), are thus obtained. Moreover, (MB, SAS) is discussed by dividing it into two factors. This all-inclusive investigation leads to the following results: (1) the protein-water many-body correlation always plays critical roles in a variety of folding/unfolding processes; (2) the hard-sphere solvent model fails when it does not correctly reproduce the protein-water many-body correlation; (3) the hard-sphere solvent model becomes problematic when the dependence of the many-body correlation on the solvent number density and temperature is essential: it is not quite suited to studies on cold and pressure denaturating of a protein; (4) when the temperature and solvent number density are limited to the ambient values, the hard-sphere solvent model is usually successful; and (5) even at the ambient

Essential roles of protein-solvent many-body correlation in solvent-entropy effect on protein folding and denaturation: Comparison between hard-sphere solvent and water

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

Oshima, Hiraku; Kinoshita, Masahiro, E-mail: kinoshit@iae.kyoto-u.ac.jp

In earlier works, we showed that the entropic effect originating from the translational displacement of water molecules plays the pivotal role in protein folding and denaturation. The two different solvent models, hard-sphere solvent and model water, were employed in theoretical methods wherein the entropic effect was treated as an essential factor. However, there were similarities and differences in the results obtained from the two solvent models. In the present work, to unveil the physical origins of the similarities and differences, we simultaneously consider structural transition, cold denaturation, and pressure denaturation for the same protein by employing the two solvent modelsmore » and considering three different thermodynamic states for each solvent model. The solvent-entropy change upon protein folding/unfolding is decomposed into the protein-solvent pair (PA) and many-body (MB) correlation components using the integral equation theories. Each component is further decomposed into the excluded-volume (EV) and solvent-accessible surface (SAS) terms by applying the morphometric approach. The four physically insightful constituents, (PA, EV), (PA, SAS), (MB, EV), and (MB, SAS), are thus obtained. Moreover, (MB, SAS) is discussed by dividing it into two factors. This all-inclusive investigation leads to the following results: (1) the protein-water many-body correlation always plays critical roles in a variety of folding/unfolding processes; (2) the hard-sphere solvent model fails when it does not correctly reproduce the protein-water many-body correlation; (3) the hard-sphere solvent model becomes problematic when the dependence of the many-body correlation on the solvent number density and temperature is essential: it is not quite suited to studies on cold and pressure denaturating of a protein; (4) when the temperature and solvent number density are limited to the ambient values, the hard-sphere solvent model is usually successful; and (5) even at the

Photonic Crystal Based Sensor for Organic Solvents and for Solvent-Water Mixtures

PubMed Central

Fenzl, Christoph; Hirsch, Thomas; Wolfbeis, Otto S.

2012-01-01

Monodisperse polystyrene nanoparticles with a diameter of 173 nm were incorporated into a polydimethylsiloxane matrix where they display an iridescent color that can be attributed to the photonic crystal effect. The film is of violet color if placed in plain water, but turns to red in the presence of the non-polar solvent n-hexane. Several solvents were studied in some detail. We show that such films are capable of monitoring the water content of ethanol/water mixtures, where only 1% (v/v) of water leads to a shift of the peak wavelength of reflected light by 5 nm. The method also can be applied to determine, both visually and instrumentally, the fraction of methanol in ethanol/methanol mixtures. Here, a fraction of 1% of methanol (v/v) results in a wavelength shift of 2 nm. The reflected wavelength is not influenced by temperature changes nor impeded by photobleaching. The signal changes are fully reversible and response times are <1 s. PMID:23235441

Changes in fluorescent emission of cationic fluorophores in the presence of n-alkanes and alcohols in different polarity solvents

NASA Astrophysics Data System (ADS)

Delgado-Camón, Arantzazu; Garriga, Rosa; Mateos, Elena; Cebolla, Vicente L.; Galbán, Javier; Membrado, Luis; Marcos, Susana de; Gálvez, Eva M.

2011-01-01

Berberine and coralyne experience either fluorescence enhancement or quenching when long hydrocarbon chain compounds (e.g., n-alkanes or alcohols) are added to their solutions, depending on solvent polarity. In polar solvents, as methanol or acetonitrile, the added compounds provide an apolar microenvironment that hinders alternative relaxation mechanisms, favouring fluorescence emission. However, alkane additions produce quenching in dichloromethane, which has been explained taking into account ion pairing between cationic fluorophore and counterion. The strong quenching measured after alcohol additions in dichloromethane suggests reversed micelle formation. Procedures and results described here may find practical applications in the development of analytical methods.

Molecular Dynamics Analysis of Lysozyme Protein in Ethanol- Water Mixed Solvent

DTIC Science & Technology

2012-01-01

molecular dynamics simulations of solvent effect on lysozyme protein, using water, ethanol, and different concentrations of water-ethanol mixtures as...understood. This work focuses on detailed molecular dynamics simulations of solvent effect on lysozyme protein, using water, ethanol, and different...using GROMACS molecular dynamics simulation (MD) code. Compared to water environment, the lysozyme structure showed remarkable changes in water

Amplification of hofmeister effect by alcohols.

PubMed

Xu, Yun; Liu, Guangming

2014-07-03

We have demonstrated that Hofmeister effect can be amplified by adding alcohols to aqueous solutions. The lower critical solution temperature behavior of poly(N-isopropylacrylamide) has been employed as the model system to study the amplification of Hofmeister effect. The alcohols can more effectively amplify the Hofmeister effect following the series methanol < ethanol < 1-propanol < 2-propanol for the monohydric alcohols and following the series d-sorbitol ≈ xylitol ≈ meso-erythritol < glycerol < ethylene glycol < methanol for the polyhydric alcohols. Our study reveals that the relative extent of amplification of Hofmeister effect is determined by the stability of the water/alcohol complex, which is strongly dependent on the chemical structure of alcohols. The more stable solvent complex formed via stronger hydrogen bonds can more effectively differentiate the anions through the anion-solvent complex interactions, resulting in a stronger amplification of Hofmeister effect. This study provides an alternative method to tune the relative strength of Hofmeister effect besides salt concentration.

Water/alcohol soluble conjugated polymers as highly efficient electron transporting/injection layer in optoelectronic devices.

PubMed

Huang, Fei; Wu, Hongbin; Cao, Yong

2010-07-01

Water/alcohol soluble conjugated polymers (WSCPs) can be processed from water or other polar solvents, which offer good opportunities to avoid interfacial mixing upon fabrication of multilayer polymer optoelectronic devices by solution processing, and can dramatically improve charge injection from high work-function metal cathode resulting in greatly enhancement of the device performance. In this critical review, the authors provide a brief review of recent developments in this field, including the materials design, functional principles, and their unique applications as interface modification layer in solution-processable multilayer optoelectronic devices (135 references).

Combining Solvent Isotope Effects with Substrate Isotope Effects in Mechanistic Studies of Alcohol and Amine Oxidation by Enzymes*

PubMed Central

Fitzpatrick, Paul F.

2014-01-01

Oxidation of alcohols and amines is catalyzed by multiple families of flavin-and pyridine nucleotide-dependent enzymes. Measurement of solvent isotope effects provides a unique mechanistic probe of the timing of the cleavage of the OH and NH bonds, necessary information for a complete description of the catalytic mechanism. The inherent ambiguities in interpretation of solvent isotope effects can be significantly decreased if isotope effects arising from isotopically labeled substrates are measured in combination with solvent isotope effects. The application of combined solvent and substrate (mainly deuterium) isotope effects to multiple enzymes is described here to illustrate the range of mechanistic insights that such an approach can provide. PMID:25448013

Preferential solvation of Brooker's merocyanine in binary solvent mixtures composed of formamides and hydroxylic solvents.

PubMed

Bevilaqua, Tharly; da Silva, Domingas C; Machado, Vanderlei G

2004-03-01

The ET polarity values of 4-[(1-methyl-4(1H)-pyridinylidene)-ethylidene]-2,5-cyclohexadien-1-one (Brooker's merocyanine) were collected in mixed-solvent systems comprising a formamide [N,N-dimethylformamide (DMF), N-methylformamide (NMF) or formamide (FA)] and a hydroxylic (water, methanol, ethanol, propan-2-ol or butan-1-ol) solvent. Binary mixtures involving DMF and the other formamides (NMF and FA) as well as NMF and FA were also studied. These data were employed in the investigation of the preferential solvation (PS) of the probe. Each solvent system was analyzed in terms of both solute-solvent and solvent-solvent interactions. These latter interactions were responsible for the synergism observed in many binary mixtures. This synergistic behaviour was observed for DMF-propan-2-ol, DMF-butan-1-ol, FA-methanol, FA-ethanol and for the mixtures of the alcohols with NMF. All data were successfully fitted to a model based on solvent-exchange equilibria, which allowed the separation of the different contributions of the solvent species in the solvation shell of the dye. The results suggest that both hydrogen bonding and solvophobic interactions contribute to the formation of the solvent complexes responsible for the observed synergistic effects in the PS of the dye.

Microfluidic Extraction of Biomarkers using Water as Solvent

NASA Technical Reports Server (NTRS)

Amashukeli, Xenia; Manohara, Harish; Chattopadhyay, Goutam; Mehdi, Imran

2009-01-01

A proposed device, denoted a miniature microfluidic biomarker extractor (mu-EX), would extract trace amounts of chemicals of interest from samples, such as soils and rocks. Traditionally, such extractions are performed on a large scale with hazardous organic solvents; each solvent capable of dissolving only those molecules lying within narrow ranges of specific chemical and physical characteristics that notably include volatility, electric charge, and polarity. In contrast, in the mu-EX, extractions could be performed by use of small amounts (typically between 0.1 and 100 L) of water as a universal solvent. As a rule of thumb, in order to enable solvation and extraction of molecules, it is necessary to use solvents that have polarity sufficiently close to the polarity of the target molecules. The mu-EX would make selection of specific organic solvents unnecessary, because mu-EX would exploit a unique property of liquid water: the possibility of tuning its polarity to match the polarity of organic solvents appropriate for extraction of molecules of interest. The change of the permittivity of water would be achieved by exploiting interactions between the translational states of water molecules and an imposed electromagnetic field in the frequency range of 300 to 600 GHz. On a molecular level, these interactions would result in disruption of the three-dimensional hydrogen-bonding network among liquid-water molecules and subsequent solvation and hydrolysis of target molecules. The mu-EX is expected to be an efficient means of hydrolyzing chemical bonds in complex macromolecules as well and, thus, enabling analysis of the building blocks of these complex chemical systems. The mu-EX device would include a microfluidic channel, part of which would lie within a waveguide coupled to an electronically tuned source of broad-band electromagnetic radiation in the frequency range from 300 to 600 GHz (see figure). The part of the microfluidic channel lying in the waveguide would

An intact eight-membered water chain in drosophilid alcohol dehydrogenases is essential for optimal enzyme activity.

PubMed

Wuxiuer, Yimingjiang; Morgunova, Ekaterina; Cols, Neus; Popov, Alexander; Karshikoff, Andrey; Sylte, Ingebrigt; Gonzàlez-Duarte, Roser; Ladenstein, Rudolf; Winberg, Jan-Olof

2012-08-01

All drosophilid alcohol dehydrogenases contain an eight-member water chain connecting the active site with the solvent at the dimer interface. A similar water chain has also been shown to exist in other short-chain dehydrogenase/reductase (SDR) enzymes, including therapeutically important SDRs. The role of this water chain in the enzymatic reaction is unknown, but it has been proposed to be involved in a proton relay system. In the present study, a connecting link in the water chain was removed by mutating Thr114 to Val114 in Scaptodrosophila lebanonensis alcohol dehydrogenase (SlADH). This threonine is conserved in all drosophilid alcohol dehydrogenases but not in other SDRs. X-ray crystallography of the SlADH(T114V) mutant revealed a broken water chain, the overall 3D structure of the binary enzyme-NAD(+) complex was almost identical to the wild-type enzyme (SlADH(wt) ). As for the SlADH(wt) , steady-state kinetic studies revealed that catalysis by the SlADH(T114V) mutant was consistent with a compulsory ordered reaction mechanism where the co-enzyme binds to the free enzyme. The mutation caused a reduction of the k(on) velocity for NAD(+) and its binding strength to the enzyme, as well as the rate of hydride transfer (k) in the ternary enzyme-NAD(+) -alcohol complex. Furthermore, it increased the pK(a) value of the group in the binary enzyme-NAD(+) complex that regulates the k(on) velocity of alcohol and alcohol-competitive inhibitors. Overall, the results indicate that an intact water chain is essential for optimal enzyme activity and participates in a proton relay system during catalysis. © 2012 The Authors Journal compilation © 2012 FEBS.

Efficient kinetic resolution of secondary alcohols using an organic solvent-tolerant esterase in non-aqueous medium.

PubMed

Gao, Wenyuan; Fan, Haiyang; Chen, Lifeng; Wang, Hualei; Wei, Dongzhi

2016-07-01

To identify an esterase-mediated kinetic resolution of secondary alcohols in non-aqueous medium. An esterase, EST4, from a marine mud metagenomic library, showed high activity and enantioselectivity for the kinetic resolution of secondary alcohols in non-aqueous medium. Using 1-phenylethanol as the model alcohol, the effects of organic solvents, acyl donors, molar ratio, temperatures and biocatalyst loading on the kinetic resolution catalyzed by the EST4 whole-cell biocatalyst were investigated and optimized. The optimized methodology was effective on resolving 16 various racemic secondary alcohols in neat n-hexane, providing excellent enantiomeric excess (up to 99.9 % ee). Moreover, EST4 exhibited a strong tolerance for high substrate concentration (up to 1 M), and the optical purity of the desired secondary alcohols was kept above 99 % ee. The esterase EST4 is a promising biocatalyst for the enantioselective synthesis of various alcohols and esters with interesting practical applications.

Surface interactions between silica particles and water and organic solvents

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

Douillard, J.M.; Elwafir, M.; Partyka, S.

1994-04-01

A silica sample has been studied by vapor adsorption and by microcalorimetric methods. The combination of these two methods in the case of water allows one to calculate all the thermodynamic terms related to the adhesion on this silica. Adhesion between silica and miscellaneous solvents has been studied by immersion microcalorimetry. The silica is slightly hydrophobic, but the enthalpy of immersion into water is the most energetic one of all the solvents studied. It appears a clear graduation of the enthalpies of immersion due to the presence of delocalized electrons in the studied solvents.

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.

Influence of the solvent in the synthesis of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals at room temperature.

PubMed

Bustamante, Eugenia L; Fernández, José L; Zamaro, Juan M

2014-06-15

The effect of the solvent on the synthesis process and on the nanocrystal characteristics of the zeolitic imidazolate framework-8 (ZIF-8) was investigated. A synthesis protocol at room temperature employing a series of aliphatic alcohols, water, dimethylformamide and acetone was employed. The results show that the solvent modifies the evolution of the reaction, altering the crystallization rates and nanocrystal sizes. Its hydrogen bond donation ability is the main factor that governs this effect. More precisely, the solvent modulates the formation of ZIF-8 nanocrystals with sizes in the range between 15 and 42 nm. When synthesized in alcohol and acetone, these nanocrystals form globular aggregates with sizes between 130 and 420 nm. In contrast, under the same synthesis conditions, when using water or dimethylformamide the ZIF phase is not developed. In alcohols other than methanol, the crystals develop pill-shaped morphologies with poorly defined facets. Moreover, a markedly fast growing kinetics is verified in these alcohols, leading to an ultra-fast crystallization of ZIF-8 in about 60s. These findings provide new information about the role of the solvent in the synthesis process of nanoZIF-8, which can be useful for controlling the crystallization rates and nanocrystal sizes of this material. Copyright © 2014 Elsevier Inc. All rights reserved.

Polysaccharide structures and interactions in a lithium chloride/urea/water solvent.

PubMed

Winkworth-Smith, Charles G; MacNaughtan, William; Foster, Tim J

2016-09-20

The molten salt hydrate, lithium chloride (LiCl)/urea/water has previously been shown to swell cellulose, but there has so far been no work done to explore its effect on other polysaccharides. In this paper we have investigated the solvent effects of LiCl/urea/water on four natural polysaccharides. Fenugreek gum and xyloglucan, which are both highly branched, were found to increase in viscosity in LiCl/urea/water relative to water, possibly due to the breakage of all intra-molecular associations whereas the viscosity of konjac glucomannan which is predominantly unbranched did not change. Locust bean gum (LBG) had a lower viscosity in LiCl/urea/water compared to water due to the disruption of aggregates. Confocal microscopy showed that fenugreek gum and LBG are able to bind to cellulose in water, however, the conformational change of fenugreek gum in these solvent conditions inhibited it from binding to cellulose in LiCl/urea/water whereas conformational change allowed xyloglucan to bind to cellulose in LiCl/urea/water whilst it was unable to bind in water. Konjac glucomannan did not bind to cellulose in either solvent system. These results provide new insights into the impact of polysaccharide fine structure on conformational change in different solvent environments. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Computational solvent system screening for the separation of tocopherols with centrifugal partition chromatography using deep eutectic solvent-based biphasic systems.

PubMed

Bezold, Franziska; Weinberger, Maria E; Minceva, Mirjana

2017-03-31

Tocopherols are a class of molecules with vitamin E activity. Among those, α-tocopherol is the most important vitamin E source in the human diet. The purification of tocopherols involving biphasic liquid systems can be challenging since these vitamins are poorly soluble in water. Deep eutectic solvents (DES) can be used to form water-free biphasic systems and have already proven applicable for centrifugal partition chromatography separations. In this work, a computational solvent system screening was performed using the predictive thermodynamic model COSMO-RS. Liquid-liquid equilibria of solvent systems composed of alkanes, alcohols and DES, as well as partition coefficients of α-tocopherol, β-tocopherol, γ-tocopherol, and σ-tocopherol in these biphasic solvent systems were calculated. From the results the best suited biphasic solvent system, namely heptane/ethanol/choline chloride-1,4-butanediol, was chosen and a batch injection of a tocopherol mixture, mainly consisting of α- and γ-tocopherol, was performed using a centrifugal partition chromatography set up (SCPE 250-BIO). A separation factor of 1.74 was achieved for α- and γ-tocopherol. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

NASA Astrophysics Data System (ADS)

Lee, Youngme; Sah, Eric; Sah, Hongkee

2015-11-01

The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60-150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5-4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.

Exploring associations between prenatal solvent exposures and teenage drug and alcohol use: a retrospective cohort study.

PubMed

Gallagher, Lisa G; Webster, Thomas F; Aschengrau, Ann

2017-03-11

Investigating the effects of prenatal and childhood exposures on behavioral health outcomes in adolescence is challenging given the lengthy period between the exposure and outcomes. We conducted a retrospective cohort study in Cape Cod, Massachusetts to evaluate the impact of prenatal and early childhood exposure to tetrachloroethylene (PCE)-contaminated drinking water on the occurrence of risk-taking behaviors as a teenager. An increased occurrence of risk-taking behaviors, particularly illicit drug use, was observed in those highly exposed to PCE. We hypothesized that there may be other sources of prenatal solvent exposure such as maternal consumption of alcoholic beverages during pregnancy which might modify the previously observed associations between PCE and risk-taking behaviors and so we conducted an exploratory analysis using available cohort data. The current report presents the results of these analyses and describes the difficulties in conducting research on long-term behavioral effects of early life exposures. The exploratory analysis compared a referent group of subjects with no early life exposure to PCE or alcohol (n = 242) to subjects with only alcohol exposure (n = 201), subjects with only PCE exposure (n = 361), and subjects with exposure to both PCE and alcohol (n = 302). Surveys completed by the subject's mother included questions on prenatal alcoholic beverage consumption and available confounding variables such as cigarette smoking and marijuana use. Surveys completed by the subjects included questions on risk-taking behaviors such as alcoholic beverage consumption and illicit drug use as a teenager and available confounding variables. PCE exposure was modeled using a leaching and transport algorithm embedded in water distribution system modeling software that estimated the amount of PCE delivered to a subject's residence during gestation and early childhood. Subjects with early life exposure to both PCE and alcohol had an

Probing the Hofmeister series beyond water: Specific-ion effects in non-aqueous solvents

NASA Astrophysics Data System (ADS)

Mazzini, Virginia; Liu, Guangming; Craig, Vincent S. J.

2018-06-01

We present an experimental investigation of specific-ion effects in non-aqueous solvents, with the aim of elucidating the role of the solvent in perturbing the fundamental ion-specific trend. The focus is on the anions: CH3COO->F->Cl->Br->I->ClO4 ->SCN- in the solvents water, methanol, formamide, dimethyl sulfoxide (DMSO), and propylene carbonate (PC). Two types of experiments are presented. The first experiment employs the technique of size exclusion chromatography to evaluate the elution times of electrolytes in the different solvents. We observe that the fundamental (Hofmeister) series is observed in water and methanol, whilst the series is reversed in DMSO and PC. No clear series is observed for formamide. The second experiment uses the quartz crystal microbalance technique to follow the ion-induced swelling and collapse of a polyelectrolyte brush. Here the fundamental series is observed in the protic solvents water, methanol, and formamide, and the series is once again reversed in DMSO and PC. These behaviours are not attributed to the protic/aprotic nature of the solvents, but rather to the polarisability of the solvents and are due to the competition between the interaction of ions with the solvent and the surface. A rule of thumb is proposed for ion specificity in non-aqueous solvents. In weakly polarisable solvents, the trends in specific-ion effects will follow those in water, whereas in strongly polarisable solvents the reverse trend will be observed. Solvents of intermediate polarisability will give weak specific-ion effects.

Probing the Hofmeister series beyond water: Specific-ion effects in non-aqueous solvents.

PubMed

Mazzini, Virginia; Liu, Guangming; Craig, Vincent S J

2018-06-14

We present an experimental investigation of specific-ion effects in non-aqueous solvents, with the aim of elucidating the role of the solvent in perturbing the fundamental ion-specific trend. The focus is on the anions: CH 3 COO - >F - >Cl - >Br - >I - >ClO 4 - >SCN - in the solvents water, methanol, formamide, dimethyl sulfoxide (DMSO), and propylene carbonate (PC). Two types of experiments are presented. The first experiment employs the technique of size exclusion chromatography to evaluate the elution times of electrolytes in the different solvents. We observe that the fundamental (Hofmeister) series is observed in water and methanol, whilst the series is reversed in DMSO and PC. No clear series is observed for formamide. The second experiment uses the quartz crystal microbalance technique to follow the ion-induced swelling and collapse of a polyelectrolyte brush. Here the fundamental series is observed in the protic solvents water, methanol, and formamide, and the series is once again reversed in DMSO and PC. These behaviours are not attributed to the protic/aprotic nature of the solvents, but rather to the polarisability of the solvents and are due to the competition between the interaction of ions with the solvent and the surface. A rule of thumb is proposed for ion specificity in non-aqueous solvents. In weakly polarisable solvents, the trends in specific-ion effects will follow those in water, whereas in strongly polarisable solvents the reverse trend will be observed. Solvents of intermediate polarisability will give weak specific-ion effects.

Solvolysis kinetics of three components of biomass using polyhydric alcohols as solvents.

PubMed

Shi, Yan; Xia, Xueying; Li, Jingdan; Wang, Jing; Zhao, Tiantian; Yang, Hongmin; Jiang, Jianchun; Jiang, Xiaoxiang

2016-12-01

The solvolysis behavior and reaction kinetics of the three components of biomass (cellulose, hemicelluloses and lignin) liquefied in polyhydric alcohols (PEG 400 or glycerol) were investigated in this paper. Three stages were observed during the solvolysis process and the main degradation stage could be further divided into two zones. The influences of solvents on the liquefaction process of three main components were compared. Based on Starink and Malek methods, kinetic parameters and mechanism functions were obtained. The derived average activation energy of cellulose, hemicellulose and lignin were 108.73, 95.66 and 94.13kJmol -1 in PEG 400, while the values were 102.16, 77.43 and 89.10kJmol -1 in glycerol, respectively. Higher efficiency was observed when using glycerol as solvent, which could be ascribed to the higher polarity value of glycerol. The conversion curves calculated with obtained mechanism models and kinetic parameters were in good agreement with the experimental data. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solubility behavior of lamivudine crystal forms in recrystallization solvents.

PubMed

Jozwiakowski, M J; Nguyen, N A; Sisco, J M; Spancake, C W

1996-02-01

Lamivudine can be obtained as acicular crystals (form I, 0.2 hydrate) from water or methanol and as bipyramidal crystals (form II, nonsolvated) from many nonaqueous solvents. Form II is thermodynamically favored in the solid state (higher melting point and greater density than form I) at ambient relative humidities. Solubility measurements on both forms versus solvent and temperature was used to determine whether entropy or enthalpy was the driving force for solubility. Solution calorimetry data indicated that form I is favored (less soluble) in all solvents studied on the basis of enthalpy alone. In higher alcohols and other organic solvents, form I has a larger entropy of solution than form II, which compensates for the enthalpic factors and results in physical stability for form II in these systems. The metastable crystal form solubility at 25 degrees C was estimated to be 1.2-2.3 times as high as the equilibrium solubility of the stable form, depending on the temperature, solvent, and crystal form. Binary solvent studies showed that > 18-20% water must be present in ethanol to convert the excess solid to form I at equilibrium.

Effect of dissolved oxygen in alcoholic beverages and drinking water on alcohol elimination in humans.

PubMed

Rhee, Su-jin; Chae, Jung-woo; Song, Byung-jeong; Lee, Eun-sil; Kwon, Kwang-il

2013-02-01

Oxygen plays an important role in the metabolism of alcohol. An increased dissolved oxygen level in alcoholic beverages reportedly accelerates the elimination of alcohol. Therefore, we evaluated the effect of dissolved oxygen in alcohol and the supportive effect of oxygenated water on alcohol pharmacokinetics after the excessive consumption of alcohol, i.e., 540 ml of 19.5% alcohol (v/v). Fifteen healthy males were included in this randomized, 3 × 3 crossover study. Three combinations were tested: X, normal alcoholic beverage and normal water; Y, oxygenated alcoholic beverage and normal water; Z, oxygenated alcoholic beverage and oxygenated water. Blood alcohol concentrations (BACs) were determined by conversion of breath alcohol concentrations. Four pharmacokinetic parameters (C(max), T(max), K(el), and AUCall) were obtained using non-compartmental analysis and the times to reach 0.05% and 0.03% BAC (T(0.05%) and T(0.03%)) were compared using one-way analysis of variance (ANOVA) and Duncan's post hoc test. With combination Z, the BAC decreased to 0.05% significantly faster (p < 0.05) than with combination X. Analyzing the pharmacokinetic parameters, the mean K(el) was significantly higher for combination Z than for combinations X and Y (p < 0.05), whereas the mean values of C(max), T(max) and AUCall did not differ significantly among the combinations. Dissolved oxygen in drinks accelerates the decrease in BAC after consuming a large amount of alcohol. However, the oxygen dissolved in the alcoholic beverage alone did not have a sufficient effect in this case. We postulate that highly oxygenated water augments the effect of oxygen in the alcoholic beverage in alcohol elimination. Therefore, it is necessary to investigate the supportive effect of ingesting additional oxygenated water after heavy drinking of normal alcoholic beverages. Copyright © 2013 Elsevier Inc. All rights reserved.

Solvent Flux Method (SFM): A Case Study of Water Access to Candida antarctica Lipase B.

PubMed

Benson, Sven P; Pleiss, Jürgen

2014-11-11

The solvent flux method (SFM) was developed to comprehensively characterize the influx of solvent molecules from the solvent environment into the active site of a protein in the framework of molecular dynamics simulations. This was achieved by introducing a solvent concentration gradient as well as partially reorienting and rescaling the velocity vector of all solvent molecules contained within a spherical volume enclosing the protein, thus inducing an accelerated solvent influx toward the active site. In addition to the detection of solvent access pathway within the protein structure, it is hereby possible to identify potential amino acid positions relevant to solvent-related enzyme engineering with high statistical significance. The method is particularly aimed at improving the reverse hydrolysis reaction rates in nonaqueous media. Candida antarctica lipase B (CALB) binds to a triglyceride-water interface with its substrate entrance channel oriented toward the hydrophobic substrate interface. The lipase-triglyceride-water system served as a model system for SFM to evaluate the influx of water molecules to the active site. As a proof of principle for SFM, a previously known water access pathway in CALB was identified as the primary water channel. In addition, a secondary water channel and two pathways for water access which contribute to water leakage between the protein and the triglyceride-water interface were identified.

Transport of Proteins Dissolved in Organic Solvents Across Biomimetic Membranes

NASA Astrophysics Data System (ADS)

Bromberg, Lev E.; Klibanov, Alexander M.

1995-02-01

Using lipid-impregnated porous cellulose membranes as biomimetic barriers, we tested the hypothesis that to afford effective transmembrane transfer of proteins and nucleic acids, the vehicle solvent should be able to dissolve both the biopolymers and the lipids. While the majority of solvents dissolve one or the other, ethanol and methanol were found to dissolve both, especially if the protein had been lyophilized from an aqueous solution of a pH remote from the protein's isoelectric point. A number of proteins, as well as RNA and DNA, dissolved in these alcohols readily crossed the lipidized membranes, whereas the same biopolymers placed in nondissolving solvents (e.g., hexane and ethyl acetate) or in those unable to dissolve lipids (e.g., water and dimethyl sulfoxide) exhibited little transmembrane transport. The solubility of biopolymers in ethanol and methanol was further enhanced by complexation with detergents and poly(ethylene glycol); significant protein and nucleic acid transport through the lipidized membranes was observed from these solvents but not from water.

In Situ Cross-Linking of Polyvinyl Alcohol Films

NASA Technical Reports Server (NTRS)

Philipp, W. H.; Shu, L. C.; May, C. E.

1984-01-01

Films or impregnated matrices readily made from aqueous polyvinyl alcohol solution. Controlled thickness films made by casting precise quantities of aqueous polymer solution on smooth surface, allowing water to evaporate and then removing film. Composite separators formed in similar fashion by impregnating cloth matrix with polyvinyl alcohol solution and drying composite. Insoluble thin hydrophilic membranes made from aqueous systems, and use of undesirable organic solvents not required.

Effects of monohydric alcohols and polyols on the thermal stability of a protein

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

Murakami, Shota; Kinoshita, Masahiro, E-mail: kinoshit@iae.kyoto-u.ac.jp

2016-03-28

The thermal stability of a protein is lowered by the addition of a monohydric alcohol, and this effect becomes larger as the size of hydrophobic group in an alcohol molecule increases. By contrast, it is enhanced by the addition of a polyol possessing two or more hydroxyl groups per molecule, and this effect becomes larger as the number of hydroxyl groups increases. Here, we show that all of these experimental observations can be reproduced even in a quantitative sense by rigid-body models focused on the entropic effect originating from the translational displacement of solvent molecules. The solvent is either puremore » water or water-cosolvent solution. Three monohydric alcohols and five polyols are considered as cosolvents. In the rigid-body models, a protein is a fused hard spheres accounting for the polyatomic structure in the atomic detail, and the solvent is formed by hard spheres or a binary mixture of hard spheres with different diameters. The effective diameter of cosolvent molecules and the packing fractions of water and cosolvent, which are crucially important parameters, are carefully estimated using the experimental data of properties such as the density of solid crystal of cosolvent, parameters in the pertinent cosolvent-cosolvent interaction potential, and density of water-cosolvent solution. We employ the morphometric approach combined with the integral equation theory, which is best suited to the physical interpretation of the calculation result. It is argued that the degree of solvent crowding in the bulk is the key factor. When it is made more serious by the cosolvent addition, the solvent-entropy gain upon protein folding is magnified, leading to the enhanced thermal stability. When it is made less serious, the opposite is true. The mechanism of the effects of monohydric alcohols and polyols is physically the same as that of sugars. However, when the rigid-body models are employed for the effect of urea, its addition is predicted to enhance

Effects of monohydric alcohols and polyols on the thermal stability of a protein

NASA Astrophysics Data System (ADS)

Murakami, Shota; Kinoshita, Masahiro

2016-03-01

The thermal stability of a protein is lowered by the addition of a monohydric alcohol, and this effect becomes larger as the size of hydrophobic group in an alcohol molecule increases. By contrast, it is enhanced by the addition of a polyol possessing two or more hydroxyl groups per molecule, and this effect becomes larger as the number of hydroxyl groups increases. Here, we show that all of these experimental observations can be reproduced even in a quantitative sense by rigid-body models focused on the entropic effect originating from the translational displacement of solvent molecules. The solvent is either pure water or water-cosolvent solution. Three monohydric alcohols and five polyols are considered as cosolvents. In the rigid-body models, a protein is a fused hard spheres accounting for the polyatomic structure in the atomic detail, and the solvent is formed by hard spheres or a binary mixture of hard spheres with different diameters. The effective diameter of cosolvent molecules and the packing fractions of water and cosolvent, which are crucially important parameters, are carefully estimated using the experimental data of properties such as the density of solid crystal of cosolvent, parameters in the pertinent cosolvent-cosolvent interaction potential, and density of water-cosolvent solution. We employ the morphometric approach combined with the integral equation theory, which is best suited to the physical interpretation of the calculation result. It is argued that the degree of solvent crowding in the bulk is the key factor. When it is made more serious by the cosolvent addition, the solvent-entropy gain upon protein folding is magnified, leading to the enhanced thermal stability. When it is made less serious, the opposite is true. The mechanism of the effects of monohydric alcohols and polyols is physically the same as that of sugars. However, when the rigid-body models are employed for the effect of urea, its addition is predicted to enhance the

Efficient and Highly Selective Solvent-Free Oxidation of Primary Alcohols to Aldehydes Using Bucky Nanodiamond.

PubMed

Lin, Yangming; Wu, Kuang-Hsu Tim; Yu, Linhui; Heumann, Saskia; Su, Dang Sheng

2017-09-11

Selective oxidation of alcohols to aldehydes is widely applicable to the synthesis of various green chemicals. The poor chemoselectivity for complicated primary aldehydes over state-of-the-art metal-free or metal-based catalysts represents a major obstacle for industrial application. Bucky nanodiamond is a potential green catalyst that exhibits excellent chemoselectivity and cycling stability for the selective oxidation of primary alcohols in diverse structures (22 examples, including aromatic, substituted aromatic, unsaturated, heterocyclic, and linear chain alcohols) to their corresponding aldehydes. The results are comparable to reported transition-metal catalysts including conventional Pt/C and Ru/C catalysts for certain substrates under solvent-free conditions. The possible activation process of the oxidant and substrates by the surface oxygen groups and defect species are revealed with model catalysts, ex situ electrochemical measurements, and ex situ attenuated total reflectance. The zigzag edges of sp 2 carbon planes are shown to play a key role in these reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solvent wash solution

DOEpatents

Neace, J.C.

1984-03-13

A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Solvent wash solution

DOEpatents

Neace, James C.

1986-01-01

Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Conformational and bioactivity analysis of insulin: freeze-drying TBA/water co-solvent system in the presence of surfactant and sugar.

PubMed

Zhang, Yong; Deng, Yingjie; Wang, Xueli; Xu, Jinghua; Li, Zhengqiang

2009-04-17

Despite the extensive research into the freeze-drying of aqueous solutions of proteins, it remains unknown whether proteins can survive the lyophilization process in a water-organic co-solvent system and how the process and additives affect the structural stability and activity of the proteins. In the present study, a conformational analysis of insulin in the absence/presence of bile salt and trehalose was carried out, before and after freeze-drying of a tert-butyl alcohol (TBA)/water co-solvent system at volume ratios of TBA to water ranging from 50/50 to 0/100. The study involved the use of ultraviolet derivative and fluorescence spectroscopy, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy. Also the bioactivity of insulin was evaluated in vivo using the streptozotocin (STZ)-induced diabetic mice as an animal model. Initial investigations indicate that the extent of the structural change of insulin depends significantly both on the TBA content and on the concentration of additives, such as sodium deoxycholate, prior to lyophilization. This could be accounted for by the phase behavior properties of the TBA/water co-solvent system, surface denaturation together with the selective and/or forced dispersion of insulin during phase separation. Lyophilized insulin in the presence of bile salt and trehalose retained more of its bioactivity and native-like structure in the solid state compared with that in the absence of additives at various TBA/water ratios, although in all cases there was a major and reversible rearrangement of secondary structure after rehydration, except for insulin at 50% TBA (v/v). Furthermore, both lyophilization in non-eutectic systems and less structural changes in the formulation process lead to more bioactivity.

Membrane augmented distillation to separate solvents from water

DOEpatents

Huang, Yu; Baker, Richard W.; Daniels, Rami; Aldajani, Tiem; Ly, Jennifer H.; Alvarez, Franklin R.; Vane, Leland M.

2012-09-11

Processes for removing water from organic solvents, such as ethanol. The processes include distillation to form a rectified overhead vapor, compression of the rectified vapor, and treatment of the compressed vapor by two sequential membrane separation steps.

Effects of solvent evaporation on water sorption/solubility and nanoleakage of adhesive systems.

PubMed

Chimeli, Talita Baumgratz Cachapuz; D'Alpino, Paulo Henrique Perlatti; Pereira, Patrícia Nóbrega; Hilgert, Leandro Augusto; Di Hipólito, Vinicius; Garcia, Fernanda Cristina Pimentel

2014-01-01

To evaluate the influence of solvent evaporation in the kinetics of water diffusion (water sorption-WS, solubility-SL, and net water uptake) and nanoleakage of adhesive systems. Disk-shaped specimens (5.0 mm in diameter x 0.8 mm in thickness) were produced (N=48) using the adhesives: Clearfil S3 Bond (CS3)/Kuraray, Clearfil SE Bond - control group (CSE)/Kuraray, Optibond Solo Plus (OS)/Kerr and Scotchbond Universal Adhesive (SBU)/3M ESPE. The solvents were either evaporated for 30 s or not evaporated (N=24/per group), and then photoactivated for 80 s (550 mW/cm2). After desiccation, the specimens were weighed and stored in distilled water (N=12) or mineral oil (N=12) to evaluate the water diffusion over a 7-day period. Net water uptake (%) was also calculated as the sum of WS and SL. Data were submitted to 3-way ANOVA/Tukey's test (α=5%). The nanoleakage expression in three additional specimens per group was also evaluated after ammoniacal silver impregnation after 7 days of water storage under SEM. Statistical analysis revealed that only the factor "adhesive" was significant (p<0.05). Solvent evaporation had no influence in the WS and SL of the adhesives. CSE (control) presented significantly lower net uptake (5.4%). The nanoleakage was enhanced by the presence of solvent in the adhesives. Although the evaporation has no effect in the kinetics of water diffusion, the nanoleakage expression of the adhesives tested increases when the solvents are not evaporated.

Effects of solvent evaporation on water sorption/solubility and nanoleakage of adhesive systems

PubMed Central

CHIMELI, Talita Baumgratz Cachapuz; D'ALPINO, Paulo Henrique Perlatti; PEREIRA, Patrícia Nóbrega; HILGERT, Leandro Augusto; DI HIPÓLITO, Vinicius; GARCIA, Fernanda Cristina Pimentel

2014-01-01

Objective To evaluate the influence of solvent evaporation in the kinetics of water diffusion (water sorption-WS, solubility-SL, and net water uptake) and nanoleakage of adhesive systems. Material and Methods Disk-shaped specimens (5.0 mm in diameter x 0.8 mm in thickness) were produced (N=48) using the adhesives: Clearfil S3 Bond (CS3)/Kuraray, Clearfil SE Bond - control group (CSE)/Kuraray, Optibond Solo Plus (OS)/Kerr and Scotchbond Universal Adhesive (SBU)/3M ESPE. The solvents were either evaporated for 30 s or not evaporated (N=24/per group), and then photoactivated for 80 s (550 mW/cm2). After desiccation, the specimens were weighed and stored in distilled water (N=12) or mineral oil (N=12) to evaluate the water diffusion over a 7-day period. Net water uptake (%) was also calculated as the sum of WS and SL. Data were submitted to 3-way ANOVA/Tukey's test (α=5%). The nanoleakage expression in three additional specimens per group was also evaluated after ammoniacal silver impregnation after 7 days of water storage under SEM. Results Statistical analysis revealed that only the factor "adhesive" was significant (p<0.05). Solvent evaporation had no influence in the WS and SL of the adhesives. CSE (control) presented significantly lower net uptake (5.4%). The nanoleakage was enhanced by the presence of solvent in the adhesives. Conclusions Although the evaporation has no effect in the kinetics of water diffusion, the nanoleakage expression of the adhesives tested increases when the solvents are not evaporated. PMID:25141201

Activity and conformation of lysozyme in molecular solvents, protic ionic liquids (PILs) and salt-water systems.

PubMed

Wijaya, Emmy C; Separovic, Frances; Drummond, Calum J; Greaves, Tamar L

2016-09-21

Improving protein stabilisation is important for the further development of many applications in the pharmaceutical, specialty chemical, consumer product and agricultural sectors. However, protein stabilization is highly dependent on the solvent environment and, hence, it is very complex to tailor protein-solvent combinations for stable protein maintenance. Understanding solvent features that govern protein stabilization will enable selection or design of suitable media with favourable solution environments to retain protein native conformation. In this work the structural conformation and activity of lysozyme in 29 solvent systems were investigated to determine the role of various solvent features on the stability of the enzyme. The solvent systems consisted of 19 low molecular weight polar solvents and 4 protic ionic liquids (PILs), both at different water content levels, and 6 aqueous salt solutions. Small angle X-ray scattering, Fourier transform infrared spectroscopy and UV-vis spectroscopy were used to investigate the tertiary and secondary structure of lysozyme along with the corresponding activity in various solvation systems. At low non-aqueous solvent concentrations (high water content), the presence of solvents and salts generally maintained lysozyme in its native structure and enhanced its activity. Due to the presence of a net surface charge on lysozyme, electrostatic interactions in PIL-water systems and salt solutions enhanced lysozyme activity more than the specific hydrogen-bond interactions present in non-ionic molecular solvents. At higher solvent concentrations (lower water content), solvents with a propensity to exhibit the solvophobic effect, analogous to the hydrophobic effect in water, retained lysozyme native conformation and activity. This solvophobic effect was observed particularly for solvents which contained hydroxyl moieties. Preferential solvophobic effects along with bulky chemical structures were postulated to result in less

Solvent Effects of Model Polymeric Corrosion Control Coatings on Water Transport and Corrosion Rate

NASA Astrophysics Data System (ADS)

Konecki, Christina

Industrial coating formulations are often made for volatile organic content compliance and ease of application, with little regard for the solvent impact on resultant performance characteristics. Our research objective was to understand the effect of both solvent retention and chemical structure on water transport through polymer films and resultant corrosion area growth of coated steel substrates. A clear, unpigmented Phenoxy(TM) thermoplastic polymer (PKHH) was formulated into resin solutions with three separate solvent blends selected by Hansen solubility parameter (HSP), boiling point, and ability to solubilize PKHH. Polymer films cast from MEK/PGME (methyl ethyl ketone/ propylene glycol methyl ether), dried under ambient conditions (AMB, > 6wt.% residual solvent) produced a porous morphology, which resulted in a corrosion area greater than 50%. We attributed this to the water-soluble solvent used in film preparation, which enabled residual PGME to be extracted by water. The resin solution prepared with CYCOH/DXL (Cyclohexanol/ 1,3 dioxolane) was selected because CYCOH is a solid at room temperature which acts as a pigment in the final film. Therefore, increasing the tortuosity of water transport, as well as a high hydrogen bonding character, which caused more interactions with water, slowing diffusion, producing a nodular morphology, and 37% less corrosion area than MEK/PGME AMB. The HSP of PKHH and EEP (ethyl 3-ethoxypropionate) are within 5% of each other, which produced a homogeneous morphology and resulted in comparable corrosion rates regardless of residual solvent content. We utilized electrochemical techniques and attenuated total reflectance- Fourier transform infrared spectroscopy to elucidate dynamic water absorption and solvent extraction in the exposed model formulations. We found that water absorption resulted in a loss of barrier properties, and increased corrosion due to the voids formed by solvent extraction. The polymer films were rejuvenated

High-repetition-rate, narrow-band dye lasers with water as a solvent for dyes

NASA Astrophysics Data System (ADS)

Ray, Alok K.; Sinha, Sucharita; Kundu, Soumitra; Kumar, Sasi; Nair, Sivagiriyal Karunakaran Sreenivasan; Pal, Tamal; Dasgupta, Kamalesh

2002-03-01

The performance of a copper vapor laser-pumped narrow-band dye laser in oscillator-amplifier configuration with water-based binary mixture solvents is described. Although oscillator efficiency in water-surfactant (sodium lauryl sulfate) solvent was comparable with that that employed pure ethanolic solvent, amplifier efficiency was found to be lower. Experiments that were carried out with vertically polarized pump beams and either horizontally or vertically polarized signal beams show that, in case of both the pump and signal having orthogonal polarization (horizontal) and same polarization (vertical), the extraction efficiency for both ethanolic and water-micelle media increased substantially from 15.7% to 18.5% and from 10% to 12.5%, respectively. However, the relative difference remained nearly the same, indicating that a slower orientational diffusion of excited dye molecules in a micellar medium is not responsible for a decrease in amplifier efficiency. Amplifier efficiency comparable with that containing ethanolic dye solutions could be obtained with a binary solvent that comprises a mixture of water and about 30% n-propanol. The performances of two efficient dyes, Rhodamine-6G and Kiton Red S, using water-based solvents were studied.

Nickel-Catalyzed Suzuki-Miyaura Cross-Coupling in a Green Alcohol Solvent for an Undergraduate Organic Chemistry Laboratory.

PubMed

Hie, Liana; Chang, Jonah J; Garg, Neil K

2015-03-10

A modern undergraduate organic chemistry laboratory experiment involving the Suzuki-Miyaura coupling is reported. Although Suzuki-Miyaura couplings typically employ palladium catalysts in environmentally harmful solvents, this experiment features the use of inexpensive nickel catalysis, in addition to a "green" alcohol solvent. The experiment employs heterocyclic substrates, which are important pharmaceutical building blocks. Thus, this laboratory procedure exposes students to a variety of contemporary topics in organic chemistry, including transition metal-catalyzed cross-couplings, green chemistry, and the importance of heterocycles in drug discovery, none of which are well represented in typical undergraduate organic chemistry curricula. The experimental protocol uses commercially available reagents and is useful in both organic and inorganic instructional laboratories.

The solvent dependent shift of the amide I band of a fully solvated peptide in methanol/water mixtures as a local probe for the solvent composition in the peptide/solvent interface

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

Gnanakaran, S

2008-01-01

We determine the shift and line-shape of the amide I band of a model AK-peptide from molecular dynamics (MD) simulations of the peptide dissolved in methanol/water mixtures with varying composition. The IR-spectra are determined from a transition dipole coupling exciton model. A simplified empirical model Hamiltonian is employed, taking both the effect of hydrogen bonding, as well as intramolecular vibrational coupling into account. We consider a single isolated AK-peptide in a mostly helical conformation, while the solvent is represented by 2600 methanol or water molecules, simulated for a pressure of 1 bar and a temperature of 300 K. Over themore » course of the simulations minor reversible conformational changes at the termini are observed, which are found to only slightly affect the calculated spectral properties. Over the entire composition range, varying from pure water to the pure methanol solvent, a monotonous blue-shift of the IR amide I band of about 8 wavenumbers is observed. The shift is found to be caused by two counter-compensating effects: An intramolecular red-shift of about 1.2 wavenumbers, due to stronger intramolecular hydrogen-bonding in a methanol-rich environment. Dominating, however, is the intermolecular solvent-dependent blue-shift of about 10 wavenumbers, being attributed to the less effective hydrogen bond donor capabilities of methanol compared to water. The importance of solvent-contribution to the IR-shift, as well as the significantly different hydrogen formation capabilities of water and methanol make the amide I band sensitive to composition changes in the local environment close the peptide/solvent interface. This allows, in principle, an experimental determination of the composition of the solvent in close proximity to the peptide surface. For the AK-peptide case they observe at low methanol concentrations a significantly enhanced methanol concentration at the peptide/solvent-interface, supposedly promoted by the partially

Properties of electrospun pollock gelatin/poly(vinyl alcohol) and pollock gelatin/poly(lactic acid) fibers

USDA-ARS?s Scientific Manuscript database

Pollock gelatin/poly(vinyl alcohol) (PVA) fibers were electrospun using deionized water as the solvent and pollock gelatin/poly(lactic acid) (PLA) fibers were electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent. The chemical, thermal, and thermal stability properties were exami...

Are Water-lean Solvent Systems Viable for Post-Combustion CO 2 Capture?

DOE PAGES

Heldebrant, David J.; Koech, Phillip K.; Rousseau, Roger; ...

2017-08-18

Here, we present here an overview of water-lean solvents that compares their projected costs and performance to aqueous amine systems, emphasizing critical areas of study needed to evaluate their performance against their water-based brethren. The work presented her focuses on bridging these knowledge gaps. Because the majority of water-lean solvents are still at the lab scale, substantial studies are still needed to model their performance at scale. This presents a significant challenge as eachformulation has different physical and thermodynamic properties and behavior, and quantifying how these different properties manifest themselves in conventional absorber-stripper configurations, or identifying new configurations that aremore » specific for a solvent’s signature behavior. We identify critical areas of study that are needed, and our efforts (e.g. custom infrastructure, molecular models) to predict, measure, and model these behaviors. Such findings are critical for determining the rheology required for heat exchanger design; absorber designs and packing to accommodate solvents with gradient changes (e.g. viscosity, contact angle, surface tension), and stripper configurations without direct steam utilization or water reflux. Another critical area of research need is to understand the molecular structure of the liquid interface and bulk as a function of CO 2 loading, and to assess whether conventional film theories accurately quantify solvent behavior, or if thermodynamic models adequately quantify activity coefficients of ions in solution. We conclude with an assessment of our efforts to aid in bridging the knowledge gaps in understanding water-lean solvents, and suggestions of what is needed to enable large-scale demonstrations to meet the United States Department of Energy’s year 2030 goal.« less

Are Water-lean Solvent Systems Viable for Post-Combustion CO 2 Capture?

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

Heldebrant, David J.; Koech, Phillip K.; Rousseau, Roger

Here, we present here an overview of water-lean solvents that compares their projected costs and performance to aqueous amine systems, emphasizing critical areas of study needed to evaluate their performance against their water-based brethren. The work presented her focuses on bridging these knowledge gaps. Because the majority of water-lean solvents are still at the lab scale, substantial studies are still needed to model their performance at scale. This presents a significant challenge as eachformulation has different physical and thermodynamic properties and behavior, and quantifying how these different properties manifest themselves in conventional absorber-stripper configurations, or identifying new configurations that aremore » specific for a solvent’s signature behavior. We identify critical areas of study that are needed, and our efforts (e.g. custom infrastructure, molecular models) to predict, measure, and model these behaviors. Such findings are critical for determining the rheology required for heat exchanger design; absorber designs and packing to accommodate solvents with gradient changes (e.g. viscosity, contact angle, surface tension), and stripper configurations without direct steam utilization or water reflux. Another critical area of research need is to understand the molecular structure of the liquid interface and bulk as a function of CO 2 loading, and to assess whether conventional film theories accurately quantify solvent behavior, or if thermodynamic models adequately quantify activity coefficients of ions in solution. We conclude with an assessment of our efforts to aid in bridging the knowledge gaps in understanding water-lean solvents, and suggestions of what is needed to enable large-scale demonstrations to meet the United States Department of Energy’s year 2030 goal.« less

Study of nanoparticles TiO2 thin films on p-type silicon substrate using different alcoholic solvents

NASA Astrophysics Data System (ADS)

Muaz, A. K. M.; Hashim, U.; Arshad, M. K. Md.; Ruslinda, A. R.; Ayub, R. M.; Gopinath, Subash C. B.; Voon, C. H.; Liu, Wei-Wen; Foo, K. L.

2016-07-01

In this paper, sol-gel method spin coating technique is adopted to prepare nanoparticles titanium dioxide (TiO2) thin films. The prepared TiO2 sol was synthesized using titanium butoxide act as a precursor and subjected to deposited on the p-type silicon oxide (p-SiO2) and glass slide substrates under room temperature. The effect of different alcoholic solvents of methanol and ethanol on the structural, morphological, optical and electrical properties were systematically investigated. The coated TiO2 thin films were annealed in furnace at 773 K for 1 h. The structural properties of the TiO2 films were examined with X-ray Diffraction (XRD). From the XRD analysis, both solvents showing good crystallinity with anatase phase were the predominant structure. Atomic Force Microscopy (AFM) was employed to study the morphological of the thin films. The optical properties were investigated by Ultraviolet-visible (UV-Vis) spectroscopy were found that ethanol as a solvent give a higher optical transmittance if compare to the methanol solvent. The electrical properties of the nanoparticles TiO2 thin films were measured using two-point-probe technique.

Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

NASA Astrophysics Data System (ADS)

Othman, Zetty Shafiqa; Hassan, Nur Hasyareeda; Zubairi, Saiful Irwan

2015-09-01

Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1, 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, 1H-NMR and 13C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.

Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

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

Othman, Zetty Shafiqa; Hassan, Nur Hasyareeda; Zubairi, Saiful Irwan

Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1,more » 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, {sup 1}H-NMR and {sup 13}C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.« less

A Coarse-Grained Protein Model in a Water-like Solvent

NASA Astrophysics Data System (ADS)

Sharma, Sumit; Kumar, Sanat K.; Buldyrev, Sergey V.; Debenedetti, Pablo G.; Rossky, Peter J.; Stanley, H. Eugene

2013-05-01

Simulations employing an explicit atom description of proteins in solvent can be computationally expensive. On the other hand, coarse-grained protein models in implicit solvent miss essential features of the hydrophobic effect, especially its temperature dependence, and have limited ability to capture the kinetics of protein folding. We propose a free space two-letter protein (``H-P'') model in a simple, but qualitatively accurate description for water, the Jagla model, which coarse-grains water into an isotropically interacting sphere. Using Monte Carlo simulations, we design protein-like sequences that can undergo a collapse, exposing the ``Jagla-philic'' monomers to the solvent, while maintaining a ``hydrophobic'' core. This protein-like model manifests heat and cold denaturation in a manner that is reminiscent of proteins. While this protein-like model lacks the details that would introduce secondary structure formation, we believe that these ideas represent a first step in developing a useful, but computationally expedient, means of modeling proteins.

Alcohol-induced drying of carbon nanotubes and its implications for alcohol/water separation: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Tian, Xingling; Yang, Zaixing; Zhou, Bo; Xiu, Peng; Tu, Yusong

2013-05-01

Alcohols are important products in chemical industry, but separating them from their aqueous solutions is very difficult due to the hydrophilic nature of alcohols. Based on molecular dynamics simulations, we observe a striking nanoscale drying phenomenon and suggest an energy-saving and efficient approach toward alcohol/water separation by using single-walled carbon nanotubes (SWNTs). We use various common linear alcohols including C1-C6 1-alcohols and glycerol for demonstration (the phenol is also used as comparison). Our simulations show that when SWNTs are immersed in aqueous alcohols solutions, although the alcohols concentration is low (1 M), all kinds of alcohols can induce dehydration (drying) of nanotubes and accumulate inside wide [(13, 13)] and narrow [(6, 6) or (7, 7)] SWNTs. In particular, most kinds of alcohols inside the narrow SWNTs form nearly uniform 1D molecular wires. Detailed energetic analyses reveal that the preferential adsorption of alcohols over water inside nanotubes is attributed to the stronger dispersion interactions of alcohols with SWNTs than water. Interestingly, we find that for the wide SWNT, the selectivity for 1-alcohols increases with the number of alcohol's carbon atoms (Ncarbon) and exhibits an exponential law with respect to Ncarbon for C1-C5 1-alcohols; for narrow SWNTs, the selectivity for 1-alcohols is very high for methanol, ethanol, and propanol, and reaches a maximum when Ncarbon = 3. The underlying physical mechanisms and the implications of these observations for alcohol/water separation are discussed. Our findings provide the possibility for efficient dehydration of aqueous alcohols (and other hydrophilic organic molecules) by using SWNT bundles/membranes.

Effect of the type and level of hydration of alcoholic solvents on the simultaneous extraction of oil and chlorogenic acids from sunflower seed press cake.

PubMed

Scharlack, Nayara K; Aracava, Keila K; Rodrigues, Christianne Ec

2017-10-01

The present study aimed to evaluate the replacement of hexane by alcoholic solvents in oil extraction from sunflower seed press cake. The use of ethanol and isopropanol has important advantages, including low toxicity and good operational safety. Thus, in the present study, solid-liquid extractions were performed in a single stage from 60 to 90 °C and in consecutive extractions in three stages at 90 °C. Solvent hydration negatively affected the extraction of oil but favored the extraction of chlorogenic acids (CAs), especially when ethanol was used. Regarding oxidative stability, the oils extracted using ethanol presented long induction times, which could be related to the high levels of not only CAs and tocopherols, but also phospholipids. Alcoholic solvents can be used for extraction to produce sunflower seed oil containing minor compounds that give it greater oxidative stability. In addition, the results obtained using hydrous ethanol showed that this solvent can yield defatted sunflower seed meal with a low content of CAs, enabling future use of the protein fraction. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Extraction of ethanol with higher carboxylic acid solvents and their toxicity to yeast

USDA-ARS?s Scientific Manuscript database

In a screening exercise for ethanol-selective extraction solvents, partitioning of ethanol and water from a 5 wt% aqueous solution into several C8 – C18 carboxylic acids was studied. Results for the acids are compared with those from alcohols of similar structure. In all cases studied, the acids exh...

Kinetics of hydrogen peroxide decomposition by catalase: hydroxylic solvent effects.

PubMed

Raducan, Adina; Cantemir, Anca Ruxandra; Puiu, Mihaela; Oancea, Dumitru

2012-11-01

The effect of water-alcohol (methanol, ethanol, propan-1-ol, propan-2-ol, ethane-1,2-diol and propane-1,2,3-triol) binary mixtures on the kinetics of hydrogen peroxide decomposition in the presence of bovine liver catalase is investigated. In all solvents, the activity of catalase is smaller than in water. The results are discussed on the basis of a simple kinetic model. The kinetic constants for product formation through enzyme-substrate complex decomposition and for inactivation of catalase are estimated. The organic solvents are characterized by several physical properties: dielectric constant (D), hydrophobicity (log P), concentration of hydroxyl groups ([OH]), polarizability (α), Kamlet-Taft parameter (β) and Kosower parameter (Z). The relationships between the initial rate, kinetic constants and medium properties are analyzed by linear and multiple linear regression.

Opening Furan for Tailoring Properties of Bio-based Poly(Furfuryl Alcohol) Thermoset.

PubMed

Falco, Guillaume; Guigo, Nathanael; Vincent, Luc; Sbirrazzuoli, Nicolas

2018-06-11

This work shows how furan ring-opening reactions were controlled by polymerization conditions to tune the cross-link density in bio-based poly(furfuryl alcohol) (PFA). The influence of water and isopropyl alcohol (IPA) on the polymerization of furfuryl alcohol, and particularly on furan ring-opening, was investigated by means of 13 C NMR and FT-IR spectroscopy. Results indicated that formation of open structures were favored in the presence of solvents, thus leading to modification of the thermo-mechanical properties compared to PFA cross-linked without solvent. Dynamic mechanical analyses showed that when slightly more open structures were present in PFA it resulted in an important decrease of the cross-link density. Despite lower glass-transition temperature and lower elastic modulus for PFA polymerized with solvent, the thermal stability remains very high (>350 °C) even with more open structures in PFA. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

27 CFR 19.385 - Making alcohol or water solutions of denaturants.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Making alcohol or water solutions of denaturants. 19.385 Section 19.385 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO... alcohol or water solutions of denaturants. If a proprietor uses a denaturant that is difficult to dissolve...

Alcohol-induced drying of carbon nanotubes and its implications for alcohol/water separation: a molecular dynamics study.

PubMed

Tian, Xingling; Yang, Zaixing; Zhou, Bo; Xiu, Peng; Tu, Yusong

2013-05-28

Alcohols are important products in chemical industry, but separating them from their aqueous solutions is very difficult due to the hydrophilic nature of alcohols. Based on molecular dynamics simulations, we observe a striking nanoscale drying phenomenon and suggest an energy-saving and efficient approach toward alcohol∕water separation by using single-walled carbon nanotubes (SWNTs). We use various common linear alcohols including C1-C6 1-alcohols and glycerol for demonstration (the phenol is also used as comparison). Our simulations show that when SWNTs are immersed in aqueous alcohols solutions, although the alcohols concentration is low (1 M), all kinds of alcohols can induce dehydration (drying) of nanotubes and accumulate inside wide [(13, 13)] and narrow [(6, 6) or (7, 7)] SWNTs. In particular, most kinds of alcohols inside the narrow SWNTs form nearly uniform 1D molecular wires. Detailed energetic analyses reveal that the preferential adsorption of alcohols over water inside nanotubes is attributed to the stronger dispersion interactions of alcohols with SWNTs than water. Interestingly, we find that for the wide SWNT, the selectivity for 1-alcohols increases with the number of alcohol's carbon atoms (Ncarbon) and exhibits an exponential law with respect to Ncarbon for C1-C5 1-alcohols; for narrow SWNTs, the selectivity for 1-alcohols is very high for methanol, ethanol, and propanol, and reaches a maximum when Ncarbon = 3. The underlying physical mechanisms and the implications of these observations for alcohol∕water separation are discussed. Our findings provide the possibility for efficient dehydration of aqueous alcohols (and other hydrophilic organic molecules) by using SWNT bundles∕membranes.

Improving agar electrospinnability with choline-based deep eutectic solvents.

PubMed

Sousa, Ana M M; Souza, Hiléia K S; Uknalis, Joseph; Liu, Shih-Chuan; Gonçalves, Maria P; Liu, LinShu

2015-09-01

Very recently our group has produced novel agar-based fibers by an electrospinning technique using water as solvent and polyvinyl alcohol (PVA) as co-blending polymer. Here, we tested the deep eutectic solvent (DES), (2-hydroxyethyl)trimethylammonium chloride/urea prepared at 1:2 molar ratio, as an alternative solvent medium for agar electrospinning. The electrospun materials were collected with an ethanol bath adapted to a previous electrospinning set-up. One weight percent agar-in-DES showed improved viscoelasticity and hence, spinnability, when compared to 1 wt% agar-in-water and pure agar nanofibers were successfully electrospun if working above the temperature of sol-gel transition (∼80 °C). By changing the solvent medium we decreased the PVA concentration (5 wt% starting solution) and successfully produced composite fibers with high agar contents (50/50 agar/PVA). Best composite fibers were formed with the 50/50 and 30/70 agar/PVA solutions. These fibers were mechanically resistant, showed tailorable surface roughness and diverse size distributions, with most of the diameters falling in the sub-micron range. Both nano and micro forms of agar fibers (used separately or combined) may have potential for the design of new and highly functional agar-based materials. Published by Elsevier B.V.

To Keep or Not to Keep? The Question of Crystallographic Waters for Enzyme Simulations in Organic Solvent

PubMed Central

Dahanayake, Jayangika N.; Gautam, Devaki N.; Verma, Rajni; Mitchell-Koch, Katie R.

2016-01-01

The use of enzymes in non-aqueous solvents expands the use of biocatalysts to hydrophobic substrates, with the ability to tune selectivity of reactions through solvent selection. Non-aqueous enzymology also allows for fundamental studies on the role of water and other solvents in enzyme structure, dynamics, and function. Molecular dynamics simulations serve as a powerful tool in this area, providing detailed atomic information about the effect of solvents on enzyme properties. However, a common protocol for non-aqueous enzyme simulations does not exist. If you want to simulate enzymes in non-aqueous solutions, how many and which crystallographic waters do you keep? In the present work, this question is addressed by determining which crystallographic water molecules lead most quickly to an equilibrated protein structure. Five different methods of selecting and keeping crystallographic waters are used in order to discover which crystallographic waters lead the protein structure to reach an equilibrated structure more rapidly in organic solutions. It is found that buried waters contribute most to rapid equilibration in organic solvent, with slow-diffusing waters giving similar results. PMID:27403032

Solvent-Ion Interactions in Salt Water: A Simple Experiment.

ERIC Educational Resources Information Center

Willey, Joan D.

1984-01-01

Describes a procedurally quick, simple, and inexpensive experiment which illustrates the magnitude and some effects of solvent-ion interactions in aqueous solutions. Theoretical information, procedures, and examples of temperature, volume and hydration number calculations are provided. (JN)

Hydrogen bond dynamics in bulk alcohols.

PubMed

Shinokita, Keisuke; Cunha, Ana V; Jansen, Thomas L C; Pshenichnikov, Maxim S

2015-06-07

Hydrogen-bonded liquids play a significant role in numerous chemical and biological phenomena. In the past decade, impressive developments in multidimensional vibrational spectroscopy and combined molecular dynamics-quantum mechanical simulation have established many intriguing features of hydrogen bond dynamics in one of the fundamental solvents in nature, water. The next class of a hydrogen-bonded liquid--alcohols--has attracted much less attention. This is surprising given such important differences between water and alcohols as the imbalance between the number of hydrogen bonds, each molecule can accept (two) and donate (one) and the very presence of the hydrophobic group in alcohols. Here, we use polarization-resolved pump-probe and 2D infrared spectroscopy supported by extensive theoretical modeling to investigate hydrogen bond dynamics in methanol, ethanol, and isopropanol employing the OH stretching mode as a reporter. The sub-ps dynamics in alcohols are similar to those in water as they are determined by similar librational and hydrogen-bond stretch motions. However, lower density of hydrogen bond acceptors and donors in alcohols leads to the appearance of slow diffusion-controlled hydrogen bond exchange dynamics, which are essentially absent in water. We anticipate that the findings herein would have a potential impact on fundamental chemistry and biology as many processes in nature involve the interplay of hydrophobic and hydrophilic groups.

Study of nanoparticles TiO{sub 2} thin films on p-type silicon substrate using different alcoholic solvents

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

Muaz, A. K. M.; Ruslinda, A. R.; Ayub, R. M.

2016-07-06

In this paper, sol-gel method spin coating technique is adopted to prepare nanoparticles titanium dioxide (TiO{sub 2}) thin films. The prepared TiO{sub 2} sol was synthesized using titanium butoxide act as a precursor and subjected to deposited on the p-type silicon oxide (p-SiO{sub 2}) and glass slide substrates under room temperature. The effect of different alcoholic solvents of methanol and ethanol on the structural, morphological, optical and electrical properties were systematically investigated. The coated TiO{sub 2} thin films were annealed in furnace at 773 K for 1 h. The structural properties of the TiO{sub 2} films were examined with X-raymore » Diffraction (XRD). From the XRD analysis, both solvents showing good crystallinity with anatase phase were the predominant structure. Atomic Force Microscopy (AFM) was employed to study the morphological of the thin films. The optical properties were investigated by Ultraviolet-visible (UV-Vis) spectroscopy were found that ethanol as a solvent give a higher optical transmittance if compare to the methanol solvent. The electrical properties of the nanoparticles TiO{sub 2} thin films were measured using two-point-probe technique.« less

Home tank water versus novel water differentially affect alcohol-induced locomotor activity and anxiety related behaviours in zebrafish.

PubMed

Tran, Steven; Facciol, Amanda; Gerlai, Robert

2016-05-01

The zebrafish may be uniquely well suited for studying alcohol's mechanisms of action in vivo, since alcohol can be administered via immersion in a non-invasive manner. Despite the robust behavioural effects of alcohol administration in mammals, studies reporting the locomotor stimulant and anxiolytic effects of alcohol in zebrafish have been inconsistent. In the current study, we examined whether differences in the type of water used for alcohol exposure and behavioural testing contribute to these inconsistencies. To answer this question, we exposed zebrafish to either home water from their housing tanks or novel water from an isolated reservoir (i.e. water lacking zebrafish chemosensory and olfactory cues) with 0% or 1% v/v alcohol for 30 min, a 2 × 2 between subject experimental designs. Behavioural responses were quantified throughout the 30-minute exposure session via a video tracking system. Although control zebrafish exposed to home water and novel water were virtually indistinguishable in their behavioural responses, alcohol's effect on locomotor activity and anxiety-like behavioural responses were dependent on the type of water used for testing. Alcohol exposure in home tank water produced a mild anxiolytic and locomotor stimulant effect, whereas alcohol exposure in novel water produced an anxiogenic effect without altering locomotor activity. These results represent a dissociation between alcohol's effects on locomotor and anxiety related responses, and also illustrate how environmental factors, in this case familiarity with the water, may interact with such effects. In light of these findings, we urge researchers to explicitly state the type of water used. Copyright © 2016 Elsevier Inc. All rights reserved.

Multipoint attachment to a support protects enzyme from inactivation by organic solvents: alpha-Chymotrypsin in aqueous solutions of alcohols and diols.

PubMed

Mozhaev, V V; Sergeeva, M V; Belova, A B; Khmelnitsky, Y L

1990-03-25

Inactivation of alpha-chymotrypsin in aqueous solutions of alcohols and diols proceeds both reversibly and irreversibly. Reversible loss of the specific enzyme activity results from conformational changes (unfolding) of the enzyme detected by fluorescence spectroscopy. Multipoint covalent attachment to the matrix of polyacryl-amide gel by copolymerization method stabilizes alpha-chymotrypsin from denaturation by alcohols, the stabilizing effect increasing with the number of bonds between the protein and the support. Immobilization protects the enzyme also from irreversible inactivation by organic solvents resulting from bimolecular aggregation and autolysis.

Solvent-coordinate free-energy landscape view of water-mediated ion-pair dissociation

NASA Astrophysics Data System (ADS)

Yonetani, Yoshiteru

2017-12-01

Water-mediated ion-pair dissociation is studied by molecular dynamics simulations of NaCl in water. Multidimensional free-energy analysis clarifies the relation between two essential solvent coordinates: the water coordination number and water-bridge formation. These two are related in a complex way. Both are necessary to describe ion-pair dissociation. The mechanism constructed with both solvent variables clearly shows the individual roles. The water coordination number is critical for starting ion-pair dissociation. Water-bridge formation is also important because it increases the likelihood of ion-pair dissociation by reducing the dissociation free-energy barrier. Additional Ca-Cl and NH4-Cl calculations show that these conclusions are unaffected by changes in the ion charge and shape. The present results will contribute to future explorations of many other molecular events such as surface water exchange and protein-ligand dissociation because the same mechanism is involved in such events.

Subtle Effects of Aliphatic Alcohol Structure on Water Extraction and Solute Aggregation in Biphasic Water/ n -Dodecane

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

Knight, Andrew W.; Qiao, Baofu; Chiarizia, Renato

Organic phase aggregation behavior of 1-octanol and its structural isomer, 2-ethylhexanol, in a biphasic n-dodecane water system is studied with a combination of physical measurement, small-angle X-ray scattering (SAXS), and atomistic molecular dynamic simulations. Physical properties of the organic phases are probed following their mixing and equilibration with immiscible water phases. Studies reveal that the interfacial tension decreases as a function of increasing alcohol concentration over the solubility range of the alcohol with no evidence for a critical aggregate concentration (cac). An uptake of water into the organic phases is quantified, as a function of alcohol content, by Karl Fischermore » titrations. The extraction of water into dodecane was further assessed as a function of alcohol concentration via the slope-analysis method sometimes employed in chemical separations. This provides a qualitative understanding of solute (water/alcohol) aggregation in the organic phase. The physical results are supported by analyses of SAXS data that reveals an emergence of aggregates in n-dodecane at elevated alcohol concentrations. The observed aggregate structure is dependent on the alcohol tail group geometry, consistent with surfactant packing parameter. The formation of these aggregates is discussed at a molecular level, where alcohol-alcohol and alcohol-water H-bonding interactions likely dominate the occurrence and morphology of the aggregates.« less

Solvent-Free Synthesis of Zeolites: Mechanism and Utility.

PubMed

Wu, Qinming; Meng, Xiangju; Gao, Xionghou; Xiao, Feng-Shou

2018-05-08

Zeolites have been extensively studied for years in different areas of chemical industry, such as shape selective catalysis, ion-exchange, and gas adsorption and separation. Generally, zeolites are prepared from solvothermal synthesis in the presence of a large amounts of solvents such as water and alcohols in sealed autoclaves under autogenous pressure. Water has been regarded as essential to synthesize zeolites for fast mass transfer of reactants, but it occupies a large space in autoclaves, which greatly reduces the yield of zeolite products. Furthermore, polluted wastes and relatively high pressure due to the presence of water solvent in the synthesis also leads to environmental and safety issues. Recently, inspired by great benefits of solvent-free synthesis, including the environmental concerns, energy consumption, safety, and economic cost, researchers continually challenge the rationale of the solvent and reconsider the age-old question "Do we actually need solvents at all in zeolite synthesis?" In this Account, we briefly summarize our efforts to rationally synthesize zeolites via a solvent-free route. Our research demonstrates that a series of silica, aluminosilicate, and aluminophosphate-based zeolites can be successfully prepared by mixing, grinding, and heating starting solid materials under solvent-free conditions. Combining an organotemplate-free synthesis with a solvent-free approach maximizes the advantages resulting in a more sustainable synthetic route, which avoids using toxic and costly organic templates and the formation of harmful gases by calcination of organic templates at high temperature. Furthermore, new insights into the solvent-free crystallization process of zeolites have been provided by modern techniques such as NMR and UV-Raman spectroscopy, which should be helpful in designing new zeolite structures and developing novel routes for synthesis of zeolites. The role of water and the vital intermediates during the crystallization of

Observation of CO2 and solvent adduct ions during negative mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of monohydric alcohols.

PubMed

Zhou, Xibin; Zhang, Yahe; Zhao, Suoqi; Hsu, Chang Samuel; Shi, Quan

2013-12-15

Monohydric alcohols are common in natural products, bio-oils, and medicine. We have found that monohydric alcohols can form O3 (ions containing three oxygen atoms) and O4 adduct ions in negative electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), which would significantly affect the composition analysis of alcohols, especially in a complex mixture. It is necessary to study the reaction pathways and the method to eliminate or reduce the 'artifact' adducts. Octadecanol, cholesterol, squalanol and two complex monohydric alcohol mixtures were selected as model compounds. These samples were subjected to negative ion ESI FT-ICR MS analysis. The composition and formation mechanism of adducts were studied by the ultrahigh-resolution accurate mass measurement for elemental composition, along with the MS(2) isolation and collision-induced dissociation (CID) experiments for structural determination. The reaction pathway of O3 adduct formation is the coupling of a monohydric alcohol ion with a CO2 to form a stable O3 ionic species by likely a covalent bond (source of CO2 is not clear). The O4 species are formed by O3 ionic species adducted with an alcohol molecule of the solvent, such as methanol or ethanol, by likely a hydrogen bond. These adduct ions could be eliminated or reduced by increasing collision energy. However, excessive collision energy would fragment monohydric alcohol ions. The formation mechanisms of O3 and O4 adducts from monohydric alcohols in negative ion ESI FT-ICR MS were proposed. The solvent adduction effects can be eliminated or reduced by optimizing the collision energy of CID in FT-ICR MS. Copyright © 2013 John Wiley & Sons, Ltd.

Breath alcohol analysis incorporating standardization to water vapour is as precise as blood alcohol analysis.

PubMed

Grubb, D; Rasmussen, B; Linnet, K; Olsson, S G; Lindberg, L

2012-03-10

A novel breath-alcohol analyzer based on the standardization of the breath alcohol concentration (BrAC) to the alveolar-air water vapour concentration has been developed and evaluated. The present study compares results with this particular breath analyzer with arterial blood alcohol concentrations (ABAC), the most relevant quantitative measure of brain alcohol exposure. The precision of analysis of alcohol in arterial blood and breath were determined as well as the agreement between ABAC and BrAC over time post-dosing. Twelve healthy volunteers were administered 0.6g alcohol/kg bodyweight via an orogastric tube. Duplicate breath and arterial blood samples were obtained simultaneously during the absorption, distribution and elimination phases of the alcohol metabolism with particular emphasis on the absorption phase. The precision of the breath analyzer was similar to the determination of blood alcohol concentration by headspace gas chromatography (CV 2.40 vs. 2.38%, p=0.43). The ABAC/BrAC ratio stabilized 30min post-dosing (2089±99; mean±SD). Before this the BrAC tended to underestimate the coexisting ABAC. In conclusion, breath alcohol analysis utilizing standardization of alcohol to water vapour was as precise as blood alcohol analysis, the present "gold standard" method. The BrAC reliably predicted the coexisting ABAC from 30min onwards after the intake of alcohol. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Temporal variation of VOC emission from solvent and water based wood stains

NASA Astrophysics Data System (ADS)

de Gennaro, Gianluigi; Loiotile, Annamaria Demarinis; Fracchiolla, Roberta; Palmisani, Jolanda; Saracino, Maria Rosaria; Tutino, Maria

2015-08-01

Solvent- and water-based wood stains were monitored using a small test emission chamber in order to characterize their emission profiles in terms of Total and individual VOCs. The study of concentration-time profiles of individual VOCs enabled to identify the compounds emitted at higher concentration for each type of stain, to examine their decay curve and finally to estimate the concentration in a reference room. The solvent-based wood stain was characterized by the highest Total VOCs emission level (5.7 mg/m3) that decreased over time more slowly than those related to water-based ones. The same finding was observed for the main detected compounds: Benzene, Toluene, Ethylbenzene, Xylenes, Styrene, alpha-Pinene and Camphene. On the other hand, the highest level of Limonene was emitted by a water-based wood stain. However, the concentration-time profile showed that water-based product was characterized by a remarkable reduction of the time of maximum and minimum emission: Limonene concentration reached the minimum concentration in about half the time compared to the solvent-based product. According to AgBB evaluation scheme, only one of the investigated water-based wood stains can be classified as a low-emitting product whose use may not determine any potential adverse effect on human health.

Microbial process for the preparation of acetic acid as well as solvent for its extraction from the fermentation broth

DOEpatents

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2006-07-11

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. This solvent is substantially devoid of mono-alkyl amines and alcohols. Solvent mixtures formed of such a modified solvent with a desired cosolvent, preferably a low boiling hydrocarbon which forms an azeotrope with water are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Microbial process for the preparation of acetic acid as well as solvent for its extraction from the fermentation broth

DOEpatents

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2002-01-01

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. This solvent is substantially devoid of mono-alkyl amines and alcohols. Solvent mixtures formed of such a modified solvent with a desired cosolvent, preferably a low boiling hydrocarbon which forms an azeotrope with water are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Application of cation-exchange solid-phase extraction for the analysis of amino alcohols from water and human plasma for verification of Chemical Weapons Convention.

PubMed

Kanaujia, Pankaj K; Tak, Vijay; Pardasani, Deepak; Gupta, A K; Dubey, D K

2008-03-28

The analysis of nitrogen containing amino alcohols, which are the precursors and degradation products of nitrogen mustards and nerve agent VX, constitutes an important aspect for verifying the compliance to the CWC (Chemical Weapons Convention). This work devotes on the development of solid-phase extraction method using silica- and polymer-based SCX (strong cation-exchange) and MCX (mixed-mode strong cation-exchange) cartridges for N,N-dialkylaminoethane-2-ols and alkyl N,N-diethanolamines, from water. The extracted analytes were analyzed by GC-MS (gas chromatography-mass spectrometry) in the full scan and selected ion monitoring modes. The extraction efficiencies of SCX and MCX cartridges were compared, and results revealed that SCX performed better. Extraction parameters, such as loading capacity, extraction solvent, its volume, and washing solvent were optimized. Best recoveries were obtained using 2 mL methanol containing 10% NH(4)OH and limits of detection could be achieved up to 5 x 10(-3) microg mL(-1) in the selected ion monitoring mode and 0.01 microg mL(-1) in full scan mode. The method was successfully employed for the detection and identification of amino alcohol present in water sample sent by Organization for Prohibition of Chemical Weapons (OPCW) in the official proficiency tests. The method was also applied to extract the analytes from human plasma. The SCX cartridge showed good recoveries of amino alcohols from human plasma after protein precipitation.

Collapse in two good solvents, swelling in two poor solvents: defying the laws of polymer solubility?

NASA Astrophysics Data System (ADS)

Mukherji, Debashish; Marques, Carlos M.; Kremer, Kurt

2018-01-01

In this work we discuss two mirror but distinct phenomena of polymer paradoxical properties in mixed solvents: co-non-solvency and co-solvency. When a polymer collapses in a mixture of two miscible good solvents the phenomenon is known as co-non-solvency, while co-solvency is a phenomenon that is associated with the swelling of a polymer in poor solvent mixtures. A typical example of co-non-solvency is provided by poly(N-isopropylacrylamide) in aqueous alcohol, while poly(methyl methacrylate) in aqueous alcohol shows co-solvency. We discuss these two phenomena to compare their microscopic origins and show that both can be understood within generic universal concepts. A broad range of polymers is therefore expected to exhibit these phenomena where specific chemical details play a lesser role than the appropriate combination of interactions between the trio of molecular components.

Reentrant behaviour in polyvinyl alcohol-borax hydrogels

NASA Astrophysics Data System (ADS)

Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

2018-01-01

Polyvinyl alcohol (PVA) hydrogels, cross-linked with varying concentrations of borax, were studied with small angle neutron scattering (SANS), x-ray diffraction (XRD) and differential thermal analysis (DTA). The SANS data satisfy the Ornstein-Zernike approximation. The hydrogels are modelled as PVA chains bound by borate cross-links. Water occupies the spaces within the three-dimensional hydrogel network. The mesh size ξ indicates reentrant behaviour i.e. at first, ξ increases and later decreases as a function of borax concentration. The behaviour is explained on the basis of the balance between the charged di-diol cross-links and the shielding by free ions in the solvent. XRD and DTA show the molecular size of water in the solvent and the glass transition temperature commensurate with reentrant behaviour.

Structure and Dynamics of Confined Alcohol-Water Mixtures.

PubMed

Bampoulis, Pantelis; Witteveen, Jorn P; Kooij, E Stefan; Lohse, Detlef; Poelsema, Bene; Zandvliet, Harold J W

2016-07-26

The effect of confinement between mica and graphene on the structure and dynamics of alcohol-water mixtures has been studied in situ and in real time at the molecular level by atomic force microscopy (AFM) at room temperature. AFM images reveal that the adsorbed molecules are segregated into faceted alcohol-rich islands on top of an ice layer on mica, surrounded by a pre-existing multilayer water-rich film. These faceted islands are in direct contact with the graphene surface, revealing a preferred adsorption site. Moreover, alcohol adsorption at low relative humidity (RH) reveals a strong preference of the alcohol molecules for the ordered ice interface. The growth dynamics of the alcohol islands is governed by supersaturation, temperature, the free energy of attachment of molecules to the island edge and two-dimensional (2D) diffusion. The measured diffusion coefficients display a size dependence on the molecular size of the alcohols, and are about 6 orders of magnitude smaller than the bulk diffusion coefficients, demonstrating the effect of confinement on the behavior of the alcohols. These experimental results provide new insights into the behavior of multicomponent fluids in confined geometries, which is of paramount importance in nanofluidics and biology.

Estimating system parameters for solvent-water and plant cuticle-water using quantum chemically estimated Abraham solute parameters.

PubMed

Liang, Yuzhen; Torralba-Sanchez, Tifany L; Di Toro, Dominic M

2018-04-18

Polyparameter Linear Free Energy Relationships (pp-LFERs) using Abraham system parameters have many useful applications. However, developing the Abraham system parameters depends on the availability and quality of the Abraham solute parameters. Using Quantum Chemically estimated Abraham solute Parameters (QCAP) is shown to produce pp-LFERs that have lower root mean square errors (RMSEs) of predictions for solvent-water partition coefficients than parameters that are estimated using other presently available methods. pp-LFERs system parameters are estimated for solvent-water, plant cuticle-water systems, and for novel compounds using QCAP solute parameters and experimental partition coefficients. Refitting the system parameter improves the calculation accuracy and eliminates the bias. Refitted models for solvent-water partition coefficients using QCAP solute parameters give better results (RMSE = 0.278 to 0.506 log units for 24 systems) than those based on ABSOLV (0.326 to 0.618) and QSPR (0.294 to 0.700) solute parameters. For munition constituents and munition-like compounds not included in the calibration of the refitted model, QCAP solute parameters produce pp-LFER models with much lower RMSEs for solvent-water partition coefficients (RMSE = 0.734 and 0.664 for original and refitted model, respectively) than ABSOLV (4.46 and 5.98) and QSPR (2.838 and 2.723). Refitting plant cuticle-water pp-LFER including munition constituents using QCAP solute parameters also results in lower RMSE (RMSE = 0.386) than that using ABSOLV (0.778) and QSPR (0.512) solute parameters. Therefore, for fitting a model in situations for which experimental data exist and system parameters can be re-estimated, or for which system parameters do not exist and need to be developed, QCAP is the quantum chemical method of choice.

Is Water a Universal Solvent for Life?

NASA Technical Reports Server (NTRS)

Pohorill, Andrew

2012-01-01

There are strong reasons to believe that the laws, principles and constraints of physics and chemistry are universal. It is much less clear how this universality translates into our understanding of the origins of life. Conventionally, discussions of this topic focus on chemistry that must be sufficiently rich to seed life. Although this is clearly a prerequisite for the emergence of living systems, I propose to focus instead on self-organization of matter into functional structures capable of reproduction, evolution and responding to environmental changes. In biology, most essential functions are largely mediated by noncovalent interactions (interactions that do not involve making or breaking chemical bonds). Forming chemical bonds is only a small part of what living systems do. There are specific implications of this point of view for universality. I will concentrate on one of these implications. Strength of non-covalent interactions must be properly tuned. If they were too weak, the system would exhibit undesired, uncontrolled response to natural fluctuations of physical and chemical parameters. If they were too strong kinetics of biological processes would be slow and energetics costly. This balance, however, is not a natural property of complex chemical systems. Instead, it has to be achieved with the aid of an appropriate solvent for life. In particular, potential solvents for life must be characterized by a high dielectric constant to ensure solubility of polar species and sufficient flexibility of biological structures stabilized by electrostatic interactions. Among these solvents, water exhibits a remarkable trait that it also promotes solvophobic (hydrophobic) interactions between non-polar species, typically manifested by a tendency of these species to aggregate and minimize their contacts with the aqueous solvent. Hydrophobic interactions are responsible, at least in part, for many self-organization phenomena in biological systems, such as the formation

Photo-kinetics of photoinduced transformation reaction of methylene green with titanium trichloride in different solvents

NASA Astrophysics Data System (ADS)

Nadeem, Syed Muhammad Saqib; Saeed, Rehana

2017-08-01

The photo-kinetics of photoinduced transformation reaction of methylene green and titanium trichloride was investigated in water and different aqueous-alcoholic solvents. The reaction is pseudo-first order, dependent only on the concentration of titanium trichloride at fixed concentration of methylene green. The effect of water and aqueous-alcoholic solvents was studied in the acidic range from 4 to 7. It was observed that the quantum yield (φ) of reaction increased with increase in polarity of the solvent. The quantum yield (φ) was high in acidic condition and decreased with further increase in acidity. The quantum yield (φ) increased sharply with increase in concentration of titanium trichloride while it almost remained unaffected by change in concentration of methylene green. The addition of ions increased the quantum yield (φ) of reaction. The increase in temperature decreased the rate and quantum yield (φ) of reaction. An electron transfer mechanism for the reaction has been proposed in accordance with the kinetics of reaction. The absence of any reaction intermediate was confirmed by spectroscopic investigations. Activation energy ( E a) was calculated by Arrhenius relation. Thermodynamic parameters such as activation energy ( E a), enthalpy change (Δ H), free energy change (Δ G) and entropy change (Δ S) were also evaluated.

Technical and economic analysis of solvent-based lithium-ion electrode drying with water and NMP

DOE PAGES

Wood, David L.; Quass, Jeffrey D.; Li, Jianlin; ...

2017-05-16

Processing lithium-ion battery (LIB) electrode dispersions with water as the solvent during primary drying offers many advantages over N-methylpyrrolidone (NMP). An in-depth analysis of the comparative drying costs of LIB electrodes is discussed for both NMP- and water-based dispersion processing in terms of battery pack $/kWh. Electrode coating manufacturing and capital equipment cost savings are compared for water vs. conventional NMP organic solvent processing. A major finding of this work is that the total electrode manufacturing costs, whether water- or NMP-based, contribute about 8–9% of the total pack cost. However, it was found that up to a 2 × reductionmore » in electrode processing (drying and solvent recovery) cost can be expected along with a $3–6 M savings in associated plant capital equipment (for a plant producing 100,000 10-kWh Plug-in Hybrid Electric Vehicle (PHEV) batteries) using water as the electrode solvent. This paper shows a different perspective in that the most important benefits of aqueous electrode processing actually revolve around capital equipment savings and environmental stewardship and not processing cost savings.« less

Experimental determination of solvent-water partition coefficients and Abraham parameters for munition constituents.

PubMed

Liang, Yuzhen; Kuo, Dave T F; Allen, Herbert E; Di Toro, Dominic M

2016-10-01

There is concern about the environmental fate and effects of munition constituents (MCs). Polyparameter linear free energy relationships (pp-LFERs) that employ Abraham solute parameters can aid in evaluating the risk of MCs to the environment. However, poor predictions using pp-LFERs and ABSOLV estimated Abraham solute parameters are found for some key physico-chemical properties. In this work, the Abraham solute parameters are determined using experimental partition coefficients in various solvent-water systems. The compounds investigated include hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX), hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), hexahydro-1,3-dinitroso-5- nitro-1,3,5-triazine (DNX), 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), and 4-nitroanisole. The solvents in the solvent-water systems are hexane, dichloromethane, trichloromethane, octanol, and toluene. The only available reported solvent-water partition coefficients are for octanol-water for some of the investigated compounds and they are in good agreement with the experimental measurements from this study. Solvent-water partition coefficients fitted using experimentally derived solute parameters from this study have significantly smaller root mean square errors (RMSE = 0.38) than predictions using ABSOLV estimated solute parameters (RMSE = 3.56) for the investigated compounds. Additionally, the predictions for various physico-chemical properties using the experimentally derived solute parameters agree with available literature reported values with prediction errors within 0.79 log units except for water solubility of RDX and HMX with errors of 1.48 and 2.16 log units respectively. However, predictions using ABSOLV estimated solute parameters have larger prediction errors of up to 7.68 log units. This large discrepancy is probably due to the missing R2NNO2

Probing Contaminant Transport to and from Clay Surfaces in Organic Solvents and Water Using Solution Calorimetry.

PubMed

Pourmohammadbagher, Amin; Shaw, John M

2015-09-15

Clays, in tailings, are a significant ongoing environmental concern in the mining and oilsands production industries, and clay rehabilitation following contamination poses challenges episodically. Understanding the fundamentals of clay behavior can lead to better environmental impact mitigation strategies. Systematic calorimetric measurements are shown to provide a framework for parsing the synergistic and antagonistic impacts of trace (i.e., parts per million level) components on the surface compositions of clays. The enthalpy of solution of as-received and "contaminated" clays, in as-received and "contaminated" organic solvents and water, at 60 °C and atmospheric pressure, provides important illustrative examples. Clay contamination included pre-saturation of clays with water and organic liquids. Solvent contamination included the addition of trace water to organic solvents and trace organic liquids to water. Enthalpy of solution outcomes are interpreted using a quantitative mass and energy balance modeling framework that isolates terms for solvent and trace contaminant sorption/desorption and surface energy effects. Underlying surface energies are shown to dominate the energetics of the solvent-clay interaction, and organic liquids as solvents or as trace contaminants are shown to displace water from as-received clay surfaces. This approach can be readily extended to include pH, salts, or other effects and is expected to provide mechanistic and quantitative insights underlying the stability of clays in tailings ponds and the behaviors of clays in diverse industrial and natural environments.

Mechanisms of Enhanced Hemoglobin Electroactivity on Carbon Electrodes upon Exposure to a Water-Miscible Primary Alcohol.

PubMed

Tom, Justin; Jakubec, Philip J; Andreas, Heather A

2018-05-01

Exposing a carbon electrode to hemoglobin (Hb) and alcoholic solvents, such as methanol, ethanol or 1-propanol, drastically changes Hb electroactivity, but until this work, the important underlying mechanisms were unclear. For the first time, we show that these alcohols impact Hb electroactivity via three mechanisms: modification of the carbon surface oxides on the glassy carbon (GC) electrode, Hb film formation, and structural changes to Hb. C 1s X-ray photoelectron spectroscopy provided evidence for significant alcohol-induced modification of the carbon surface oxides, and differential pulse voltammetry showed links between these modifications and Hb electroactivity. Spectroscopic ellipsometry showed that Hb films formed during exposure to Hb- and alcohol-containing electrolytes increased in thickness with increasing alcohol content, although film thickness played only a minor role in Hb electroactivity. Alcohol-induced structural changes in Hb are confirmed with UV-visible absorption and fluorescence data, showing that Hb denaturation also was a significant factor in increasing Hb electroactivity. Carbon-surface-oxide modification and Hb denaturation worked in tandem to maximally increase the Hb electroactivity in 60% methanol. While in ethanol and 1-propanol, the significant increases in Hb electroactivity caused by Hb denaturation were offset by an increase in Hb-inhibiting carbon surface oxides. Knowledge of these mechanisms shows the impact of alcohols on both Hb and carbon electrodes, allows for thoughtful design of the Hb-sensing system, is vital for proper analysis of Hb electroactivity in the presence of these alcohols (e.g., when used as binder solvents for immobilizing Hb into films), and provides fundamental understanding of the Hb-carbon interactions.

Solvent for urethane adhesives and coatings and method of use

DOEpatents

Simandl, Ronald F.; Brown, John D.; Holt, Jerrid S.

2010-08-03

A solvent for urethane adhesives and coatings, the solvent having a carbaldehyde and a cyclic amide as constituents. In some embodiments the solvent consists only of miscible constituents. In some embodiments the carbaldehyde is benzaldehyde and in some embodiments the cyclic amide is N-methylpyrrolidone (M-pyrole). An extender may be added to the solvent. In some embodiments the extender is miscible with the other ingredients, and in some embodiments the extender is non-aqueous. For example, the extender may include isopropanol, ethanol, tetrahydro furfuryl alcohol, benzyl alcohol, Gamma-butyrolactone or a caprolactone. In some embodiments a carbaldehyde and a cyclic amide are heated and used to separate a urethane bonded to a component.

Polyaniline - Carrageenan - Polyvinyl Alcohol Composite Material Synthesized Via Interfacial Polymerization, its Morphological Characteristics and Enhanced Solubility in Water

NASA Astrophysics Data System (ADS)

Montalbo, R. C. K.; Marquez, M. C.

2017-09-01

In recent years, conducting polyaniline (PAni) has been a popular interest of research in the field of conducting polymers due to its relatively low cost, ease of production, good conductivity, and environmental stability. Many studies however, have focused on improving its short-comings such as its limited processability and solubility in common solvents. In this study, PAni, soluble in water was produced via interfacial polymerization with chloroform as the organic solvent. Poly(vinyl alcohol) (PVA) and kappa(κ), iota(ι) and lambda(λ) - carrageenan (κCGN, ιCGN, λCGN) were added to the aqueous layer to stabilize PAni in the medium. FTIR and UV-Vis absorption spectra of the solutions as well as the fabricated film confirmed the existence of PAni emeraldine salt (PAni-ES). FTIR spectrum also confirmed the peaks corresponding to the interaction of PAni with the CGNs. Moreover, PVA-CGN played a very large role on the stability of the PAni nanofibers integrated on the PVA-CGN matrix. The morphologies of the products were further investigated using SEM and TEM. Polymer electrolyte for supercapacitor or an interfacial layer for organic solar cell is being targeted as potential application of the synthesized water soluble PAni.

Nanosized solvent superstructures in ultramolecular aqueous dilutions: twenty years' research using water proton NMR relaxation.

PubMed

Demangeat, Jean-Louis

2013-04-01

proton nuclear magnetic resonance (NMR) relaxation times T1, T2, T1/T2 are sensitive to motion and organization of water molecules. Especially, increase in T1/T2 reflects a higher degree of structuring. My purpose was to look at physical changes in water in ultrahigh aqueous dilutions. Samples were prepared by iterative centesimal (c) dilution with vigorous agitation, ranging between 3c and 24c (Avogadro limit 12c). Solutes were silica-lactose, histamine, manganese-lactose. Solvents were water, NaCl 0.15 M or LiCl 0.15 M. Solvents underwent strictly similar, simultaneous dilution/agitation, for each level of dilution, as controls. NMR relaxation was studied within 0.02-20 MHz. No changes were observed in controls. Increasing T1 and T1/T2 were found in dilutions, which persisted beyond 9c (manganese-lactose), 10c (histamine) and 12c (silica-lactose). For silica-lactose in LiCl, continuous decrease in T2 with increase in T1/T2 within the 12c-24c range indicated growing structuring of water despite absence of the initial solute. All changes vanished after heating/cooling. These findings were interpreted in terms of nanosized (>4-nm) supramolecular structures involving water, nanobubbles and ions, if any. Additional study of low dilutions of silica-lactose revealed increased T2 and decreased T1/T2 compared to solvent, within the 10(-3)-10(-6) range, reflecting transient solvent destructuring. This could explain findings at high dilution. Proton NMR relaxation demonstrated modifications of the solvent throughout the low to ultramolecular range of dilution. The findings suggested the existence of superstructures that originate stereospecifically around the solute after an initial destructuring of the solvent, developing more upon dilution and persisting beyond 12c. Copyright © 2013 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

Determination of water traces in various organic solvents using Karl Fischer method under FIA conditions.

PubMed

Dantan, N; Frenzel, W; Küppers, S

2000-05-31

Flow injection methods utilising the Karl Fischer (KF) reaction with spectrophotometric and potentiometric detection are described for the determination of the trace water content in various organic solvents. Optimisation of the methods resulted in an accessible (linear) working range of 0.01-0.2% water for many solvents studied with a typical precision of 1-2% R.S.D. Only 50 mul of organic solvent was injected and the sampling frequency was about 120 samples per h. Since the slopes of the calibration curves were different for different solvents appropriate calibration was required. Problems associated with spectrophotometric detection and caused by refractive index changes were pointed out and a nested-loop configuration was proposed to overcome this kind of interference. The potentiometric method with a novel flow-through detector cell was shown to surpass the performance of spectrophotometric detection in any respect. The characteristics of the procedures developed made them well applicable for on-line monitoring of technical solvent distillations in an industrial plant.

Polymer collapse in miscible good solvents is a generic phenomenon driven by preferential adsorption

PubMed Central

Mukherji, Debashish; Marques, Carlos M.; Kremer, Kurt

2014-01-01

Water and alcohol, such as methanol or ethanol, are miscible and, individually, good solvents for poly(N-isopropylacrylamide) (PNIPAm), but this polymer precipitates in water–alcohol mixtures. The intriguing behaviour of solvent mixtures that cannot dissolve a given polymer or a given protein, while the same macromolecule dissolves well in each of the cosolvents, is called cononsolvency. It is a widespread phenomenon, relevant for many formulation steps in the physicochemical and pharmaceutical industry, that is usually explained by invoking specific chemical details of the mixtures: as such, it has so far eluded any generic explanation. Here, by using a combination of simulations and theory, we present a simple and universal treatment that requires only the preferential interaction of one of the cosolvents with the polymer. The results show striking quantitative agreement with experiments and chemically specific simulations, opening a new perspective towards an operational understanding of macromolecular solubility. PMID:25216245

27 CFR 20.112 - Special industrial solvents general-use formula.

Code of Federal Regulations, 2010 CFR

2010-04-01

... general-use formula. (a) A special industrial solvent is any article made with any other ingredients combined with the ingredients in the minimum ratios prescribed in this section. A special industrial... alcohol. (b) Special industrial solvents are intended for use as ingredients or solvents in manufacturing...

27 CFR 20.112 - Special industrial solvents general-use formula.

Code of Federal Regulations, 2013 CFR

2013-04-01

... general-use formula. (a) A special industrial solvent is any article made with any other ingredients combined with the ingredients in the minimum ratios prescribed in this section. A special industrial... alcohol. (b) Special industrial solvents are intended for use as ingredients or solvents in manufacturing...

27 CFR 20.112 - Special industrial solvents general-use formula.

Code of Federal Regulations, 2011 CFR

2011-04-01

... general-use formula. (a) A special industrial solvent is any article made with any other ingredients combined with the ingredients in the minimum ratios prescribed in this section. A special industrial... alcohol. (b) Special industrial solvents are intended for use as ingredients or solvents in manufacturing...

27 CFR 20.112 - Special industrial solvents general-use formula.

Code of Federal Regulations, 2014 CFR

2014-04-01

... general-use formula. (a) A special industrial solvent is any article made with any other ingredients combined with the ingredients in the minimum ratios prescribed in this section. A special industrial... alcohol. (b) Special industrial solvents are intended for use as ingredients or solvents in manufacturing...

27 CFR 20.112 - Special industrial solvents general-use formula.

Code of Federal Regulations, 2012 CFR

2012-04-01

... general-use formula. (a) A special industrial solvent is any article made with any other ingredients combined with the ingredients in the minimum ratios prescribed in this section. A special industrial... alcohol. (b) Special industrial solvents are intended for use as ingredients or solvents in manufacturing...

Hot and cold water as a supercritical solvent

NASA Astrophysics Data System (ADS)

Fuentevilla, Daphne Anne

This dissertation addresses the anomalous properties of water at high temperatures near the vapor-liquid critical point and at low temperatures in the supercooled liquid region. The first part of the dissertation is concerned with the concentration dependence of the critical temperature, density, and pressure of an aqueous sodium chloride solution. Because of the practical importance of an accurate knowledge of critical parameters for industrial, geochemical, and biological applications, an empirical equation for the critical locus of aqueous sodium chloride solutions was adopted in 1999 by the International Association for the Properties of Water and Steam (IAPWS) as a guideline. However, since this original Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride was developed, two new theoretical developments occurred, motivating the first part of this dissertation. Here, I present a theory-based formulation for the critical parameters of aqueous sodium chloride solutions as a proposed replacement for the empirical formulation currently in use. This formulation has been published in the International Journal of Thermophysics and recommended by the Executive Committee of IAPWS for adoption as a Revised Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride. The second part of the dissertation addresses a new concept, considering cold water as a supercritical solvent. Based on the idea of a second, liquid-liquid, critical point in supercooled water, we explore the possibility of supercooled water as a novel supercooled solvent through the thermodynamics of critical phenomena. In 2006, I published a Physical Review letter presenting a parametric scaled equation of state for supercooled-water. Further developments based on this work led to a phenomenological mean-field "two-state" model, clarifying the nature of the phase separation in a polyamorphic single-component liquid. In this dissertation, I modify this two-state model to

Solubility determination of raloxifene hydrochloride in ten pure solvents at various temperatures: Thermodynamics-based analysis and solute-solvent interactions.

PubMed

Ahad, Abdul; Shakeel, Faiyaz; Alfaifi, Omar Ali; Raish, Mohammad; Ahmad, Ajaz; Al-Jenoobi, Fahad I; Al-Mohizea, Abdullah M

2018-06-10

The purpose of the present study was to determine the solubility of raloxifene hydrochloride (RHCl) in ten solvents: water, ethanol, isopropyl alcohol (IPA), ethylene glycol (EG), propylene glycol (PG), polyethylene glycol-400 (PEG-400), Transcutol, 1-butanol, dimethyl sulfoxide (DMSO), and ethyl acetate (EA) at temperatures of 298.2-323.2 K and a pressure of 0.1 MPa. The solubility data obtained was fitted upon "Apelblat and Van't Hoff" equations. The maximum mole fraction solubility of RHCl was obtained in DMSO (5.02 × 10 -2 at 323.2 K), followed by PEG-400 (5.92 × 10 -3 at 323.2 K), EA (3.11 × 10 -3 at 323.2 K), Transcutol (1.22 × 10 -3 at 323.2 K), PG (2.19 × 10 -4 at 323.2 K), 1-butanol (1.96 × 10 -4 at 323.2 K), IPA (1.47 × 10 -4 at 323.2 K), ethanol (7.90 × 10 -5 at 323.2 K), EG (6.65 × 10 -5 at 323.2 K), and water (3.60 × 10 -5 at 323.2 K). Similar fashions were noticed at each studied temperature. The higher solubility of RHCl in DMSO, PEG-400, EA, and Transcutol was possibly referable to their lower polarity in comparison with water. The molecular interactions between the solute and solvent molecules were estimated by calculating parameters like activity coefficients, and more prominent solute-solvent molecular interactions were noted for RHCl-DMSO, RHCl-EA, and RHCl-PEG-400 in comparison with the other solute-solvent combinations. The outcomes of the "apparent thermodynamic analysis" showed that the dissolution of RHCl was "endothermic, spontaneous and entropy-driven" in all investigated solvents. The obtained solubility data of RHCl in commonly used solvents could be useful in the purification, recrystallization, and dosage form design of the drug. Copyright © 2018 Elsevier B.V. All rights reserved.

SOLVENT EXTRACTION PROCESS

DOEpatents

Jonke, A.A.

1957-10-01

In improved solvent extraction process is described for the extraction of metal values from highly dilute aqueous solutions. The process comprises contacting an aqueous solution with an organic substantially water-immiscible solvent, whereby metal values are taken up by a solvent extract phase; scrubbing the solvent extract phase with an aqueous scrubbing solution; separating an aqueous solution from the scrubbed solvent extract phase; and contacting the scrubbed solvent phase with an aqueous medium whereby the extracted metal values are removed from the solvent phase and taken up by said medium to form a strip solution containing said metal values, the aqueous scrubbing solution being a mixture of strip solution and an aqueous solution which contains mineral acids anions and is free of the metal values. The process is particularly effective for purifying uranium, where one starts with impure aqueous uranyl nitrate, extracts with tributyl phosphate dissolved in carbon tetrachloride, scrubs with aqueous nitric acid and employs water to strip the uranium from the scrubbed organic phase.

27 CFR 19.385 - Making alcohol or water solutions of denaturants.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Making alcohol or water solutions of denaturants. 19.385 Section 19.385 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Denaturing Operations and Manufacture of Articles Rules for...

Proliferation of spacecraft-associated Acinetobacter on alcohol solvents

NASA Astrophysics Data System (ADS)

Mogul, Rakesh; Cepeda, Ivonne; Brasali, Hania; Gornick, Trevor; Jain, Chirag; Kim, Eun Jin; Nguyen, Vinh Bao; Oei, Alex; Rodriguez, Joseph; Walker, Jillian; Savla, Gautam

The Acinetobacter are the most abundant Gram-negative and non-spore forming bacteria found in the cleanroom facilities for Mars spacecraft. The spacecraft-associated Acinetobacter are extremotolerant towards hydrogen peroxide and have been shown to increase in abundance as a result of the spacecraft assembly process. To better understand the oligotrophic growth in the cleanroom environments, we have measured the growth of several Acinetobacter strains against ethanol and isopropanol, which are cleaning solvents used in the spacecraft assembly process. Our studies show that A. radioresistens 50v1, which was isolated from Mars Odyssey orbiter, optimally proliferates on 300 mM ethanol under minimal conditions at a growth rate that is 2-fold higher than that of the A. radioresistens type strain (strain 43998 (T) ). The impact of transition metals on the growth rates followed the trend of Fe (2+) > Mn (2+) > Zn (2+) , where Zn (2+) was inhibitory. In contrast, no growth on ethanol was observed for the novel species A. phoenicis 2P01AA, which was isolated from the facilities for the Mars Phoenix lander. Alcohol dehydrogenase activities measured in rich and minimal media paralleled these observations with the 50v1 strain possessing higher specific activities than the type strain, and the 2P01AA strain displaying no measurable activity in rich media. Preliminary studies indicate that isopropanol is insufficient as an energy source when in culture. The significance of these results as well as the observed differences between the Odyssey and Phoenix-associated strains will be discussed.

Estimation of the nucleation kinetics for the anti-solvent crystallisation of paracetamol in methanol/water solutions

NASA Astrophysics Data System (ADS)

Ó'Ciardhá, Clifford T.; Frawley, Patrick J.; Mitchell, Niall A.

2011-08-01

In this work the primary nucleation kinetics have been estimated for the anti-solvent crystallisation of paracetamol in methanol-water solutions from metastable zone widths (MSZW) and induction times at 25 °C. Laser back-scattering via a focused beam reflectance Measurement (FBRM ®) is utilised to detect the onset of nucleation. The theoretical approach of Kubota was employed to estimate the nucleation kinetics, which accounts for the sensitivity of the nucleation detection technique. This approach is expanded in this work to analyse the induction time for an anti-solvent crystallisation process. Solvent composition is known to have a significant impact on the measured induction times and MSZW. The induction time in this paper was measured from 40% to 70% mass water and the MSZW is measured from 40% to 60% mass water. The primary focus of the paper was to gauge the extent of how solvent composition affects nucleation kinetics so that this effect may be incorporated into a population balance model. Furthermore, the effects of solvent composition on the estimated nucleation rates are investigated. The primary nucleation rates were found to decrease with dynamic solvent composition, with the extent of their reduction linked to the gradient of the solubility curve. Finally, both MSZW and induction time methods have been found to produce similar estimates for the nucleation parameters.

Microfluidic solvent extraction of poly(vinyl alcohol) droplets: effect of polymer structure on particle and capsule formation.

PubMed

Sharratt, W N; Brooker, A; Robles, E S J; Cabral, J T

2018-04-26

We investigate the formation of poly(vinyl alcohol) microparticles by the selective extraction of aqueous polymer solution droplets, templated by microfluidics and subsequently immersed in a non-solvent bath. The role of polymer molecular mass (18-105 kg mol-1), degree of hydrolysis (88-99%) and thus solubility, and initial solution concentration (0.01-10% w/w) are quantified. Monodisperse droplets with radii ranging from 50 to 500 μm were produced at a flow-focusing junction with carrier phase hexadecane and extracted into ethyl acetate. Solvent exchange and extraction result in droplet shrinkage, demixing, coarsening and phase-inversion, yielding polymer microparticles with well-defined dimensions and internal microstructure. Polymer concentration, varied from below the overlap concentration c* to above the concentrated crossover c**, as estimated by viscosity measurements, was found to have the largest impact on the final particle size and extraction timescale, while polymer mass and hydrolysis played a secondary role. These results are consistent with the observation that the average polymer concentration upon solidification greatly exceeds c**, and that the internal microparticle porosity is largely unchanged. However, reducing the initial polymer concentration to well below c* (approximately 100×) and increasing droplet size yields thin-walled (100's of nm) capsules which controllably crumple upon extraction. The symmetry of the process can be readily broken by imposing extraction conditions at an impermeable surface, yielding large, buckled, cavity morphologies. Based on these results, we establish robust design criteria for polymer capsules and particles, demonstrated here for poly(vinyl alcohol), with well-defined shape, dimensions and internal microstructure.

Biotransformation in Double-Phase Systems: Physiological Responses of Pseudomonas putida DOT-T1E to a Double Phase Made of Aliphatic Alcohols and Biosynthesis of Substituted Catechols

PubMed Central

Rojas, Antonia; Duque, Estrella; Schmid, Andreas; Hurtado, Ana; Ramos, Juan-Luis; Segura, Ana

2004-01-01

Pseudomonas putida strain DOT-T1E is highly tolerant to organic solvents, with a logPow (the logarithm of the partition coefficient of a solvent in a two-phase water-octanol system of ≥2.5. Solvent tolerant microorganisms can be exploited to develop double-phase (organic solvent and water) biotransformation systems in which toxic substrates or products are kept in the organic phase. We tested P. putida DOT-T1E tolerance to different aliphatic alcohols with a logPow value between 2 and 4, such as decanol, nonanol, and octanol, which are potentially useful in biotransformations in double-phase systems in which compounds with a logPow around 1.5 are produced. P. putida DOT-T1E responds to aliphatic alcohols as the second phase through cis-to-trans isomerization of unsaturated cis fatty acids and through efflux of these aliphatic alcohols via a series of pumps that also extrude aromatic hydrocarbons. These defense mechanisms allow P. putida DOT-T1E to survive well in the presence of high concentrations of the aliphatic alcohols, and growth with nonanol or decanol occurred at a high rate, whereas in the presence of an octanol double-phase growth was compromised. Our results support that the logPow of aliphatic alcohols correlates with their toxic effects, as octanol (logPow = 2.9) has more negative effects in P. putida cells than 1-nonanol (logPow = 3.4) or 1-decanol (logPow = 4). A P. putida DOT-T1E derivative bearing plasmid pWW0-xylE::Km transforms m-xylene (logPow = 3.2) into 3-methylcatechol (logPow = 1.8). The amount of 3-methylcatechol produced in an aliphatic alcohol/water bioreactor was 10- to 20-fold higher than in an aqueous medium, demonstrating the usefulness of double-phase systems for this particular biotransformation. PMID:15184168

Specific interactions of alcohols and non-alcohols with a biologically active boronic acid derivative: a spectroscopic study.

PubMed

Geethanjali, H S; Melavanki, R M; Nagaraja, D; Patil, N R; Thipperudrappa, J; Kusanur, R A

2016-08-01

The photophysical properties of 4-fluoro-2-methoxyphenyl boronic acid (4FMPBA) are characterized using absorption and fluorescence techniques in series of non-alcohols and alcohols. The results are analyzed using different solvent polarity functions and Kamlet and Catalan's multiple regression approaches. The excited state dipole moment and change in dipole moment are calculated using both the solvatochromic shift method and Reichardt's microscopic solvent polarity parameter ETN. The ground state dipole moment is evaluated using quantum chemical calculations. It is found that general solute-solvent and hydrogen bond interactions are operative in this system. A red shift of ~ 9 nm in the emission spectra is observed with an increase in the solvent polarity, which depicts π→π(*) transitions, as well as the possibility of an intramolecular charge transfer (ICT) character in the emitting singlet state of 4FMPBA. The relative quantum yield, radiative and non-radiative decay constants are calculated in alkanes and alcohols using the single point method. It is found that the quantum yield of the molecule varies from 16.81% to 50.79% with the change in solvent polarity, indicating the dependence of fluorescence on the solvent environment. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Method Using Water-Based Solvent to Prepare Li7La3Zr2O12 Solid Electrolytes.

PubMed

Huang, Xiao; Lu, Yang; Jin, Jun; Gu, Sui; Xiu, Tongping; Song, Zhen; Badding, Michael E; Wen, Zhaoyin

2018-05-09

Li-garnet Li 7 La 3 Zr 2 O 12 (LLZO) is a promising candidate of solid electrolytes for high-safety solid-state Li + ion batteries. However, because of its high reactivity to water, the preparation of LLZO powders and ceramics is not easy for large-scale amounts. Herein, a method applying water-based solvent is proposed to demonstrate a possible solution. Ta-doped LLZO, that is, Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO), and its LLZTO/MgO composite ceramics are made by attrition milling, followed by a spray-drying process using water-based slurries. The impacts of parameters of the method on the structure and properties of green and sintered pellets are studied. A relative density of ∼95%, a Li-ion conductivity of ∼3.5 × 10 -4 S/cm, and uniform grain size LLZTO/MgO garnet composite ceramics are obtained with an attrition-milled LLZTO/MgO slurry that contains 40 wt % solids and 2 wt % polyvinyl alcohol binder. Li-sulfur batteries based on these ceramics are fabricated and work under 25 °C for 20 cycles with a Coulombic efficiency of 100%. This research demonstrates a promising mass production method for the preparation of Li-garnet ceramics.

Fabrication of Janus particles composed of poly (lactic-co-glycolic) acid and hard fat using a solvent evaporation method.

PubMed

Matsumoto, Akihiro; Murao, Satoshi; Matsumoto, Michiko; Watanabe, Chie; Murakami, Masahiro

The feasibility of fabricating Janus particles based on phase separation between a hard fat and a biocompatible polymer was investigated. The solvent evaporation method used involved preparing an oil-in-water (o/w) emulsion with a mixture of poly (lactic-co-glycolic) acid (PLGA), hard fat, and an organic solvent as the oil phase and a polyvinyl alcohol aqueous solution as the water phase. The Janus particles were formed when the solvent was evaporated to obtain certain concentrations of PLGA and hard fat in the oil phase, at which phase separation was estimated to occur based on the phase diagram analysis. The hard fat hemisphere was proven to be the oil phase using a lipophilic dye Oil Red O. When the solvent evaporation process was performed maintaining a specific volume during the emulsification process; Janus particles were formed within 1.5 h. However, the formed Janus particles were destroyed by stirring for over 6 h. In contrast, a few Janus particles were formed when enough water to dissolve the oil phase solvent was added to the emulsion immediately after the emulsification process. The optimized volume of the solvent evaporation medium dominantly formed Janus particles and maintained the conformation for over 6 h with stirring. These results indicate that the formation and stability of Janus particles depend on the rate of solvent evaporation. Therefore, optimization of the solvent evaporation rate is critical to obtaining stable PLGA and hard fat Janus particles.

Reversed phase liquid chromatography with UV absorbance and flame ionization detection using a water mobile phase and a cyano propyl stationary phase Analysis of alcohols and chlorinated hydrocarbons.

PubMed

Quigley, W W; Ecker, S T; Vahey, P G; Synovec, R E

1999-10-01

The development of liquid chromatography with a commercially available cyano propyl stationary phase and a 100% water mobile phase is reported. Separations were performed at ambient temperature, simplifying instrumental requirements. Excellent separation efficiency using a water mobile phase was achieved, for example N=18 800, or 75 200 m(-1), was obtained for resorcinol, at a retention factor of k'=4.88 (retention time of 9.55 min at 1 ml min(-1) for a 25 cmx4.6 mm i.d. column, packed with 5 mum diameter particles with the cyano propyl stationary phase). A separation via reversed phase liquid chromatography (RP-LC) with a 100% water mobile phase of six phenols and related compounds was compared to a separation of the same compounds by traditional RP-LC, using octadecylsilane (ODS), i.e. C18, bound to silica and an aqueous mobile phase modified with acetonitrile. Nearly identical analysis time was achieved for the separation of six phenols and related compounds using the cyano propyl stationary phase with a 100% water mobile phase, as compared to traditional RP-LC requiring a relatively large fraction of organic solvent modifier in the mobile phase (25% acetonitrile:75% water). Additional understanding of the retention mechanism with the 100% water mobile phase was obtained by relating measured retention factors of aliphatic alcohols, phenols and related compounds, and chlorinated hydrocarbons to their octanol:water partition coefficients. The retention mechanism is found to be consistent with a RP-LC mechanism coupled with an additional retention effect due to residual hydroxyl groups on the cyano propyl stationary phase. Advantages due to a 100% water mobile phase for the chemical analysis of alcohol mixtures and chlorinated hydrocarbons are reported. By placing an absorbance detector in-series and preceding a novel drop interface to a flame ionization detector (FID), selective detection of a separated mixture of phenols and related compounds and aliphatic

Halogenated solvent remediation

DOEpatents

Sorenson, Jr., Kent S.

2008-11-11

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

Nano porous silicon microcavity sensor for determination organic solvents and pesticide in water

NASA Astrophysics Data System (ADS)

Pham, Van Hoi; Van Nguyen, Thuy; Nguyen, The Anh; Pham, Van Dai; Bui, Huy

2014-12-01

In this paper we present a sensing method using nano-porous silicon microcavity sensor, which was developed in order to obtain simultaneous determination of two volatile substances with different solvent concentrations as well as very low pesticide concentration in water. The temperature of the solution and the velocity of the air stream flowing through the solution have been used to control the response of the sensor for different solvent solutions. We study the dependence of the cavity-resonant wavelength shift on solvent concentration, velocity of the airflow and solution temperature. The wavelength shift depends linearly on concentration and increases with solution temperature and velocity of the airflow. The dependence of the wavelength shift on the solution temperature in the measurement contains properties of the temperature dependence of the solvent vapor pressure, which characterizes each solvent. As a result, the dependence of the wavelength shift on the solution temperature discriminates between solutions of ethanol and acetone with different concentrations. This suggests a possibility for the simultaneous determination of the volatile substances and their concentrations. On the other hand, this method is able to detect the presence of atrazine pesticide by the shift of the resonant wavelength, with good sensitivity (0.3 nm pg-1 ml) and limit of detection (LOD) (0.8-1.4 pg ml-1), that we tested for concentrations in the range from 2.15 to 21.5 pg ml-1, which is the range useful for monitoring acceptable water for human consumption.

Chemical Analysis and Risk Assessment of Diethyl Phthalate in Alcoholic Beverages with Special Regard to Unrecorded Alcohol

PubMed Central

Leitz, Jenny; Kuballa, Thomas; Rehm, Jürgen; Lachenmeier, Dirk W.

2009-01-01

Background Phthalates are synthetic compounds with a widespread field of applications. For example, they are used as plasticizers in PVC plastics and food packaging, or are added to personal care products. Diethyl phthalate (DEP) may be used to denature alcohol, e.g., for cosmetic purposes. Public health concerns of phthalates include carcinogenic, teratogenic, hepatotoxic and endocrine effects. The aim of this study was to develop and validate a method for determining phthalates in alcohol samples and to provide a risk assessment for consumers of such products. Methodology/Principal Findings A liquid-liquid extraction procedure was optimized by varying the following parameters: type of extraction solvent (cyclohexane, n-hexane, 1,1,2-trichlorotrifluoroethane), the ratio extraction solvent/sample volume (1∶1 to 50∶1) and the number of extraction repetitions (1–10). The best extraction yield (99.9%) was achieved with the solvent 1,1,2-trichlorotrifluoroethane, an extraction solvent volume/sample volume ratio of 10∶1 and a double extraction. For quantification, gas chromatography/mass spectrometry with deuterated internal standards was used. The investigated samples were alcoholic beverages and unrecorded alcohol products from different countries (n = 257). Two unrecorded alcohol samples from Lithuania contained diethyl phthalate in concentrations of 608 mg/L and 210 mg/L. Conclusions/Significance The consumption of the phthalate-positive unrecorded alcohols would exceed tolerable daily intakes as derived from animal experiments. Both positive samples were labelled as cosmetic alcohol, but had clearly been offered for human consumption. DEP seems to be unsuitable as a denaturing agent as it has no effect on the organoleptic properties of ethanol. In light of our results that DEP might be consumed by humans in unrecorded alcohols, the prohibition of its use as a denaturing agent should be considered. PMID:19956573

L-cysteine-derived ambidextrous gelators of aromatic solvents and ethanol/water mixtures.

PubMed

Pal, Amrita; Dey, Joykrishna

2013-02-19

A series of L-cysteine-derived double hydrocarbon chain amphiphilic gelators L-(3-alkyl-carbamoylsulfanyl)-2-(3-alkylurido)propionic acid with different hydrocarbon chain lengths (C6-C16) was designed and synthesized. These gelators efficiently gelate only aromatic solvents. The gelation ability increased with the increase of chain length up to C14, but then it dropped with further increase of chain length. The C12 and C14 derivatives also gelled ethanol/water mixtures. The gels were characterized by a number of methods, including FT-IR, NMR, and XRD spectroscopy, electron microscopy, and rheology. The amphiphiles were observed to form either flat lamellar or ribbonlike aggregates in aromatic solvents as well as in ethanol/water mixtures. The gelation in all the solvents employed was observed to be thermoreversible. The gel-to-sol transition temperature as well as mechanical strength of the organogels were observed to increase with the hydrocarbon chain length. Both types of gels of C8-C16 amphiphiles have gel-to-sol transition temperatures above the physiological temperature (310 K). FT-IR and variable temperature (1)H NMR measurements suggested that van der Waals interactions have major contribution in the gelation process. The gel-to-sol transition temperature and mechanical strength of the organogels in ethanol/water mixtures was observed to be higher than those of benzene organogel.

Drinking water to reduce alcohol craving? A randomized controlled study on the impact of ghrelin in mediating the effects of forced water intake in alcohol addiction.

PubMed

Koopmann, Anne; Lippmann, Katharina; Schuster, Rilana; Reinhard, Iris; Bach, Patrick; Weil, Georg; Rietschel, Marcella; Witt, Stephanie H; Wiedemann, Klaus; Kiefer, Falk

2017-11-01

Recent data suggest that ghrelin is involved in the pathophysiology of alcohol use disorders, affecting alcohol self-administration and craving. Gastric ghrelin secretion is reduced by stomach distension. We now tested the hypothesis whether the clinically well-known effects of high-volume water intake on craving reduction in alcoholism is mediated by acute changes in ghrelin secretion. In this randomized human laboratory study, we included 23 alcohol-dependent male inpatient subjects who underwent alcohol cue exposure. Participants of the intervention group drank 1000ml of mineral water within 10min directly thereafter, compared to the participants of the control group who did not. Craving and plasma concentrations of acetylated ghrelin were measured ten times during the 120min following the alcohol cue exposure session. In the intervention group, a significant decrease in acetylated ghrelin in plasma compared to the control group was observed. This decrease was correlated to a reduction in patients' subjective level of craving. In the control group, no decrease of acetylated ghrelin in plasma and no association between alcohol craving and changes in plasma concentrations of acetylated ghrelin were observed. Our results present new evidence that the modulation in the ghrelin system by oral water intake mediates the effects of volume intake with craving reduction in alcohol use disorders. Hence, in addition to pharmacological interventions with ghrelin antagonists, the reduction of physiological ghrelin secretion might be a target for future interventions in the treatment of alcohol craving. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein dynamics in organic media at varying water activity studied by molecular dynamics simulation.

PubMed

Wedberg, Rasmus; Abildskov, Jens; Peters, Günther H

2012-03-01

In nonaqueous enzymology, control of enzyme hydration is commonly approached by fixing the thermodynamic water activity of the medium. In this work, we present a strategy for evaluating the water activity in molecular dynamics simulations of proteins in water/organic solvent mixtures. The method relies on determining the water content of the bulk phase and uses a combination of Kirkwood-Buff theory and free energy calculations to determine corresponding activity coefficients. We apply the method in a molecular dynamics study of Candida antarctica lipase B in pure water and the organic solvents methanol, tert-butyl alcohol, methyl tert-butyl ether, and hexane, each mixture at five different water activities. It is shown that similar water activity yields similar enzyme hydration in the different solvents. However, both solvent and water activity are shown to have profound effects on enzyme structure and flexibility.

Effects of concentration, temperature and solvent composition on density and apparent molar volume of the binary mixtures of cationic-anionic surfactants in methanol-water mixed solvent media.

PubMed

Bhattarai, Ajaya; Chatterjee, Sujeet Kumar; Niraula, Tulasi Prasad

2013-01-01

The accurate measurements on density of the binary mixtures of cetyltrimethylammonium bromide and sodium dodecyl sulphate in pure water and in methanol(1) + water (2) mixed solvent media containing (0.10, 0.20, and 0.30) volume fractions of methanol at 308.15, 318.15, and 323.15 K are reported. The concentrations are varied from (0.03 to 0.12) mol.l(-1) of sodium dodecyl sulphate in presence of ~ 5.0×10(-4) mol.l(-1) cetyltrimethylammonium bromide. The results showed almost increase in the densities with increasing surfactant mixture concentration, also the densities are found to decrease with increasing temperature over the entire concentration range, investigated in a given mixed solvent medium and these values are found to decrease with increasing methanol content in the solvent composition. The concentration dependence of the apparent molar volumes appear to be negligible over the entire concentration range, investigated in a given mixed solvent medium and the apparent molar volumes increase with increasing temperature and are found to decrease with increasing methanol content in the solvent composition.

40 CFR 52.254 - Organic solvent usage.

Code of Federal Regulations, 2011 CFR

2011-07-01

... volume of solvent: (1) A combination of hydrocarbons, alcohols, aldehydes, esters, ethers, or ketones... benzoate; 8 percent; (3) A combination of ethylbenzene, ketones having branched hydrocarbon structures...

Halogenated solvent remediation

DOEpatents

Sorenson, Kent S.

2004-08-31

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

Differential permeation of artemia cysts and cucumber seeds by alcohols

NASA Technical Reports Server (NTRS)

Smith, C. W.; Siegel, S. M.

1975-01-01

The rate of penetration of the simpler alcohols into brine shrimp cysts and cucumber seeds was studied. In solutions below 70% the rate of penetration is related to lipid solvent capacity of the alcohol. In concentrations above 70%, particularly in absolute alcohols, methanol penetrates brine shrimp rapidly and ethanol penetrates slowly. All the other alcohols tested did not penetrate the dormant structures. Ethionine and deuteroxy-methanol did not affect the rate of penetration of methanol. It is suggested that in dehydrated membranes the lipid moiety is protected by a continuous sheet of protein. Methanol, which is fairly similar to water, is probably able to penetrate the membrane by initiating a conformation change in the protein, exposing the lipid which subsequently dissolves in the methanol thus destroying the membrane.

Differentiation of Chemical Components in a Binary Solvent Vapor Mixture Using Carbon/Polymer Composite-Based Chemiresistors

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

Patel, Sanjay V.; Jenkins, Mark W.; Hughes, Robert C.

1999-07-19

We demonstrate a ''universal solvent sensor'' constructed from a small array of carbon/polymer composite chemiresistors that respond to solvents spanning a wide range of Hildebrand volubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs solvent vapors, the composite film swells, the average separation between carbon particles increases, and an increase in film resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, dlisopropyhnethylphosphonate (DIMP), and water are correctly identified (''classified'') using three chemiresistors, their compositemore » coatings chosen to span the full range of volubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified, following classification, two sensors suffice to determine the concentrations of both vapor components. Polyethylene vinylacetate and polyvinyl alcohol (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon-particle-composite films are sensitive to less than 0.25{degree}A relative humidity. The Sandia-developed VERI (Visual-Empirical Region of Influence) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from water vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal components analysis, VERI handles both linear and nonlinear data with equal ease. In the present study the maximum speciation accuracy is achieved by an array containing three or four sensor

Interdroplet attractive forces in AOT water-in-oil microemulsions formed in subcritical and supercritical solvents

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

Tingey, J.M.; Fulton, J.L.; Smith, R.D.

1990-03-08

The van der Waals attractive interactions between aqueous droplets in water-in-oil type microemulsions have been investigated for a range of continuous-phase solvents including the alkanes from methane to isooctane and the noble gases, krypton and xenon. Hamaker constants for water droplets with surfactant shells of the sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in subcritical and supercritical solvents were calculated by using Lifshitz theory and the resulting interaction potential calculations qualitatively account for many features of the phase behavior of these systems.

Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.

PubMed

Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

2014-12-26

In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time.

Incorporation of the TIP4P water model into a continuum solvent for computing solvation free energy

NASA Astrophysics Data System (ADS)

Yang, Pei-Kun

2014-10-01

The continuum solvent model is one of the commonly used strategies to compute solvation free energy especially for large-scale conformational transitions such as protein folding or to calculate the binding affinity of protein-protein/ligand interactions. However, the dielectric polarization for computing solvation free energy from the continuum solvent is different than that obtained from molecular dynamic simulations. To mimic the dielectric polarization surrounding a solute in molecular dynamic simulations, the first-shell water molecules was modeled using a charge distribution of TIP4P in a hard sphere; the time-averaged charge distribution from the first-shell water molecules were estimated based on the coordination number of the solute, and the orientation distribution of the first-shell waters and the intermediate water molecules were treated as that of a bulk solvent. Based on this strategy, an equation describing the solvation free energy of ions was derived.

Separation properties of aluminium-plastic laminates in post-consumer Tetra Pak with mixed organic solvent.

PubMed

Zhang, S F; Zhang, L L; Luo, K; Sun, Z X; Mei, X X

2014-04-01

The separation properties of the aluminium-plastic laminates in postconsumer Tetra Pak structure were studied in this present work. The organic solvent blend of benzene-ethyl alcohol-water was used as the separation reagent. Then triangle coordinate figure analysis was taken to optimize the volume proportion of various components in the separating agent and separation process. And the separation temperature of aluminium-plastic laminates was determined by the separation time, efficiency, and total mass loss of products. The results show that cost-efficient separations perform best with low usage of solvents at certain temperatures, for certain times, and within a certain range of volume proportions of the three components in the solvent agent. It is also found that similar solubility parameters of solvents and polyethylene adhesives (range 26.06-34.85) are a key factor for the separation of the aluminium-plastic laminates. Such multisolvent processes based on the combined-system concept will be vital to applications in the recycling industry.

Theoretical analysis of co-solvent effect on the proton transfer reaction of glycine in a water-acetonitrile mixture

NASA Astrophysics Data System (ADS)

Kasai, Yukako; Yoshida, Norio; Nakano, Haruyuki

2015-05-01

The co-solvent effect on the proton transfer reaction of glycine in a water-acetonitrile mixture was examined using the reference interaction-site model self-consistent field theory. The free energy profiles of the proton transfer reaction of glycine between the carboxyl oxygen and amino nitrogen were computed in a water-acetonitrile mixture solvent at various molar fractions. Two types of reactions, the intramolecular proton transfer and water-mediated proton transfer, were considered. In both types of the reactions, a similar tendency was observed. In the pure water solvent, the zwitterionic form, where the carboxyl oxygen is deprotonated while the amino nitrogen is protonated, is more stable than the neutral form. The reaction free energy is -10.6 kcal mol-1. On the other hand, in the pure acetonitrile solvent, glycine takes only the neutral form. The reaction free energy from the neutral to zwitterionic form gradually increases with increasing acetonitrile concentration, and in an equally mixed solvent, the zwitterionic and neutral forms are almost isoenergetic, with a difference of only 0.3 kcal mol-1. The free energy component analysis based on the thermodynamic cycle of the reaction also revealed that the free energy change of the neutral form is insensitive to the change of solvent environment but the zwitterionic form shows drastic changes. In particular, the excess chemical potential, one of the components of the solvation free energy, is dominant and contributes to the stabilization of the zwitterionic form.

Toxic hepatitis in occupational exposure to solvents

PubMed Central

Malaguarnera, Giulia; Cataudella, Emanuela; Giordano, Maria; Nunnari, Giuseppe; Chisari, Giuseppe; Malaguarnera, Mariano

2012-01-01

The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work. PMID:22719183

Alcohols react with MCM-41 at room temperature and chemically modify mesoporous silica.

PubMed

Björklund, Sebastian; Kocherbitov, Vitaly

2017-08-30

Mesoporous silica has received much attention due to its well-defined structural order, high surface area, and tunable pore diameter. To successfully employ mesoporous silica for nanotechnology applications it is important to consider how it is influenced by solvent molecules due to the fact that most preparation procedures involve treatment in various solvents. In the present work we contribute to this important topic with new results on how MCM-41 is affected by a simple treatment in alcohol at room temperature. The effects of alcohol treatment are characterized by TGA, FTIR, and sorption calorimetry. The results are clear and show that treatment of MCM-41 in methanol, ethanol, propanol, butanol, pentanol, or octanol at room temperature introduces alkoxy groups that are covalently bound to the silica surface. It is shown that alcohol treated MCM-41 becomes more hydrophobic and that this effect is sequentially more prominent going from methanol to octanol. Chemical formation of alkoxy groups onto MCM-41 occurs both for calcined and hydroxylated MCM-41 and the alkoxy groups are hydrolytically unstable and can be replaced by silanol groups after exposure to water. The results are highly relevant for mesoporous silica applications that involve contact or treatment in protic solvents, which is very common.

Alcohols as Substrates and Solvents for the Construction of 3-Alkoxylated-2-Oxindoles by Direct Alkoxylation of 3-Halooxindoles.

PubMed

Lin, Bing; Chen, Zhi-Yong; Liu, Huan-Huan; Wei, Qi-Di; Feng, Ting-Ting; Zhou, Ying; Wang, Can; Liu, Xiong-Li; Yuan, Wei-Cheng

2017-05-13

Described herein is an environmentally benign method for the synthesis of multisubstituted 3-alkoxylated-2-oxindoles 3 via direct alkoxylation of 3-halooxindoles 1 . A wide variety of such multisubstituted 3-alkoxylated-2-oxindole scaffolds were smoothly obtained in good yields (up to 94%) by heating in an oil bath at 35 °C for 24 h. A particularly valuable feature of this method was the development of environment-friendly chemistry using alcohols 2 as both the substrates and solvents in the presence of a catalytic amount of base.

Microcalorimetric study of thermal unfolding of lysozyme in water/glycerol mixtures: An analysis by solvent exchange model

NASA Astrophysics Data System (ADS)

Spinozzi, Francesco; Ortore, Maria Grazia; Sinibaldi, Raffaele; Mariani, Paolo; Esposito, Alessandro; Cinelli, Stefania; Onori, Giuseppe

2008-07-01

Folded protein stabilization or destabilization induced by cosolvent in mixed aqueous solutions has been studied by differential scanning microcalorimetry and related to difference in preferential solvation of native and denatured states. In particular, the thermal denaturation of a model system formed by lysozyme dissolved in water in the presence of the stabilizing cosolvent glycerol has been considered. Transition temperatures and enthalpies, heat capacity, and standard free energy changes have been determined when applying a two-state denaturation model to microcalorimetric data. Thermodynamic parameters show an unexpected, not linear, trend as a function of solvent composition; in particular, the lysozyme thermodynamic stability shows a maximum centered at water molar fraction of about 0.6. Using a thermodynamic hydration model based on the exchange equilibrium between glycerol and water molecules from the protein solvation layer to the bulk, the contribution of protein-solvent interactions to the unfolding free energy and the changes of this contribution with solvent composition have been derived. The preferential solvation data indicate that lysozyme unfolding involves an increase in the solvation surface, with a small reduction of the protein-preferential hydration. Moreover, the derived changes in the excess solvation numbers at denaturation show that only few solvent molecules are responsible for the variation of lysozyme stability in relation to the solvent composition.

Renewable Gasoline, Solvents, and Fuel Additives from 2,3-Butanediol.

PubMed

Harvey, Benjamin G; Merriman, Walter W; Quintana, Roxanne L

2016-07-21

2,3-Butanediol (2,3-BD) is a renewable alcohol that can be prepared in high yield from biomass sugars. 2,3-BD was selectively dehydrated in a solvent-free process to a complex mixture of 2-ethyl-2,4,5-trimethyl-1,3-dioxolanes and 4,5-dimethyl-2isopropyl dioxolanes with the heterogeneous acid catalyst Amberlyst-15. The purified dioxolane mixture exhibited an anti-knock index of 90.5, comparable to high octane gasoline, and a volumetric net heat of combustion 34 % higher than ethanol. The solubility of the dioxolane mixture in water was only 0.8 g per 100 mL, nearly an order of magnitude lower than the common gasoline oxygenate methyl tert-butyl ether. The dioxolane mixture has potential applications as a sustainable gasoline blending component, diesel oxygenate, and industrial solvent. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic Liquids in Selective Oxidation: Catalysts and Solvents.

PubMed

Dai, Chengna; Zhang, Jie; Huang, Chongpin; Lei, Zhigang

2017-05-24

Selective oxidation has an important role in environmental and green chemistry (e.g., oxidative desulfurization of fuels and oxidative removal of mercury) as well as chemicals and intermediates chemistry to obtain high-value-added special products (e.g., organic sulfoxides and sulfones, aldehydes, ketones, carboxylic acids, epoxides, esters, and lactones). Due to their unique physical properties such as the nonvolatility, thermal stability, nonexplosion, high polarity, and temperature-dependent miscibility with water, ionic liquids (ILs) have attracted considerable attention as reaction solvents and media for selective oxidations and are considered as green alternatives to volatile organic solvents. Moreover, for easy separation and recyclable utilization, IL catalysts have attracted unprecedented attention as "biphasic catalyst" or "immobilized catalyst" by immobilizing metal- or nonmetal-containing ILs onto mineral or polymer supports to combine the unique properties of ILs (chemical and thermal stability, capacity for extraction of polar substrates and reaction products) with the extended surface of the supports. This review highlights the most recent outcomes on ILs in several important typical oxidation reactions. The contents are arranged in the series of oxidation of sulfides, oxidation of alcohols, epoxidation of alkenes, Baeyer-Villiger oxidation reaction, oxidation of alkanes, and oxidation of other compounds step by step involving ILs as solvents, catalysts, reagents, or their combinations.

Water extractable arabinoxylan aerogels prepared by supercritical CO2 drying.

PubMed

Marquez-Escalante, Jorge; Carvajal-Millan, Elizabeth; Miki-Yoshida, Mario; Alvarez-Contreras, Lorena; Toledo-Guillén, Alma Rosa; Lizardi-Mendoza, Jaime; Rascón-Chu, Agustín

2013-05-14

Water extractable arabinoxylan (WEAX) aerogels were prepared by extracting the solvent from the alcogels (WEAX hydrogels with an alcohol as the solvent) with carbon dioxide under supercritical conditions. WEAX aerogels were characterized using scanning electron microscopy and adsorption and desorption nitrogen isotherms. The micrographs indicate a heterogeneous porous network structure in WEAX aerogel. Adsorption/desorption nitrogen isotherms of this material were type IV, which confirm that this material possess a mesoporous structure. WEAX aerogels rehydration capability was evaluated and the water absorption mechanism was determined. The WEAX aerogels water absorption mechanism was non-Fickian (n = 0.54).

A new irreversible enzyme-aided esterification method in organic solvents.

PubMed

Jeromin, Günter E; Zoor, Annegreth

2008-05-01

A new irreversible esterification method for carboxylic acids catalyzed by a lipase from Candida antarctica (Novozyme 435) in organic solvents has been developed. The water produced during the process is chemically destroyed by a corresponding ester of acetoacetate, which acts as a sacrificial substrate in this reaction. The flavour esters isobutyl acetate, methyl butyrate, ethyl butyrate and benzyl butyrate were synthesized either in small scale (0.05 mol) or large scale (1 mol). The yields range from 82 to 92% within 24 h at 52 degrees C. Optimal molar ratios of reactants were 1:1:1 (carboxylic acid:alcohol:acetoacetate).

Preparation of Water-Selective Polybutadiene Membranes and Their Use in Drying Alcohols by Pervaporation and Vapor Permeation Technologies

EPA Science Inventory

Separating azeotrope-forming solvent-water mixtures by conventional distillation poses technical, economic, and environmental challenges. Membrane technology using water-permselective membranes provides an efficient alternative for water removal from solvents. We present here a n...

Protein instability toward organic solvent/water emulsification: implications for protein microencapsulation into microspheres.

PubMed

Sah, H

1999-01-01

The objective of this study was to investigate the behavior of three proteins at an organic solvent/water interface. To simulate the first microencapsulation step of a water-in-oil-in-water emulsion technique, a water-in-oil emulsion was prepared by emulsifying an aqueous protein solution in either methylene chloride or ethyl acetate. Phase separation was then followed to collect protein samples from the aqueous phase and the organic solvent/water interface. Their properties were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size exclusion-HPLC. Bovine serum albumin was relatively unharmed during emulsification, compared to other proteins such as ovalbumin and lysozyme. In particular, the methylene chloride treatment on ovalbumin led to the formation of a large quantity of water-insoluble, solid-like aggregates and changes in the composition of monomeric and dimeric ovalbumin species. With regard to the question of ovalbumin recovery, only 9.74 approximately 37.72% of the used ovalbumin was present in the aqueous phases after emulsification. Similar penchant was noted with lysozyme. Water-insoluble aggregates brought with by emulsification were found to be covalently bound. Interestingly, less emulsification-induced denaturing effects were observed with ethyl acetate. Our study clearly demonstrated the emulsification-induced adverse events that were detrimental to the integrity of proteins and the importance of preserving protein stability toward microencapsulation.

Measuring CO 2 and N 2 O Mass Transfer into GAP-1 CO 2 –Capture Solvents at Varied Water Loadings

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

Whyatt, Greg A.; Zwoster, Andy; Zheng, Feng

This paper investigates the CO 2 and N 2 O absorption behavior in the water-lean gamma amino propyl (GAP)-1/TEG solvent system using a wetted-wall contactor. Testing was performed on a blend of GAP-1 aminosilicone in triethylene glycol at varied water loadings in the solvent. Measurements were made with CO 2 and N 2 O at representative lean (0.04 mol CO 2/mol alkalinity), middle (0.13 mol CO 2 /mol alkalinity) and rich (0.46 mol CO 2 /mol alkalinity) solvent loadings at 0, 5, 10 and 15 wt% water loadings at 40, 60 and 80C° and N 2 O at (0.08-0.09 molmore » CO 2 /mol alkalinity) at 5 wt% water at 40, 60 and 80C°. CO 2 flux was found to be non-linear with respect to log mean pressure driving force (LMPD). Liquid-film mass transfer coefficients (k'g) were calculated by subtracting the gas film resistance (determined from a correlation from literature) from the overall mass transfer measurement. The resulting k'g values for CO 2 and N 2 O in GAP-1/TEG mixtures were found to be higher than that of 5M aqueous monoethanolamine under comparable driving force albeit at higher solvent viscosities. The k'g values for CO 2 were also found to decrease with increasing solvent water content and increase with a decrease in temperature. These observations indicate that mass transfer of CO 2 in GAP-1/TEG is linked to the physical solubility of CO 2 , which is higher in organic solvents compared to water. This paper expands on the understanding of the unique mass transfer behavior and kinetics of CO 2 capture in water-lean solvents.« less

Solvent and substituent effects on aggregation constants of perylene bisimide π-stacks--a linear free energy relationship analysis.

PubMed

Chen, Zhijian; Fimmel, Benjamin; Würthner, Frank

2012-08-14

A series of six perylene bisimides (PBIs) with hydrophilic and hydrophobic side chains at the imide nitrogens were applied for a comparative study of the solvent and structural effects on the aggregation behaviour of this class of dyes. A comparison of the binding constants in tetrachloromethane at room temperature revealed the highest binding constant of about 10(5) M(-1) for a PBI bearing 3,4,5-tridodecyloxyphenyl substituents at the imide nitrogens, followed by 3,4,5-tridodecylphenyl and alkyl-substituted PBIs, whereas no aggregation could be observed in the accessible concentration range for PBIs equipped with bulky 2,6-diisopropylphenyl substituents at the imide nitrogens. The aggregation behaviour of three properly soluble compounds was investigated in 17 different solvents covering a broad polarity range from nonpolar n-hexane to highly polar DMSO and water. Linear free energy relationships (LFER) revealed a biphasic behaviour between Gibbs free energies of aggregation and common empirical solvent polarity scales indicating particularly strong π-π stacking interactions in nonpolar aliphatic and polar alcoholic solvents whilst the weakest binding is observed in dichloromethane and chloroform. Accordingly, PBI aggregation is dominated by electrostatic interactions in nonpolar solvents and by solvophobic interactions in protic solvents. In water, the aggregation constant is increased far beyond LFER expectations pointing at a pronounced hydrophobic effect.

Solvent Dependent Disorder in M 2(BzOip) 2(H 2O)·Solvate (M = Co or Zn)

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

McCormick, Laura; Morris, Samuel A.; Teat, Simon J.

Coordination polymers derived from 5-benzyloxy isophthalic acid (H 2BzOip) are rare, with only three reported that do not contain additional bridging ligands, of which two M 2(BzOip) 2(H 2O) (M = Co and Zn) are isomorphous. It was hoped that by varying the solvent system in a reaction between H 2BzOip and M(OAc) 2 (M = Co and Zn), from water to a water/alcohol mixture, coordination polymers of different topology could be formed. Instead, two polymorphs of the existing M 2(BzOip) 2(H 2O) (M = Co and Zn) were isolated from aqueous methanol and aqueous ethanol, in which a smallmore » number of guest solvent molecules are present in the crystals. These guest water molecules disrupt the hexaphenyl embrace motif, leading to varying degrees of disorder of the benzyl groups.« less

Solvent Dependent Disorder in M 2(BzOip) 2(H 2O)·Solvate (M = Co or Zn)

DOE PAGES

McCormick, Laura; Morris, Samuel A.; Teat, Simon J.; ...

2017-12-24

Coordination polymers derived from 5-benzyloxy isophthalic acid (H 2BzOip) are rare, with only three reported that do not contain additional bridging ligands, of which two M 2(BzOip) 2(H 2O) (M = Co and Zn) are isomorphous. It was hoped that by varying the solvent system in a reaction between H 2BzOip and M(OAc) 2 (M = Co and Zn), from water to a water/alcohol mixture, coordination polymers of different topology could be formed. Instead, two polymorphs of the existing M 2(BzOip) 2(H 2O) (M = Co and Zn) were isolated from aqueous methanol and aqueous ethanol, in which a smallmore » number of guest solvent molecules are present in the crystals. These guest water molecules disrupt the hexaphenyl embrace motif, leading to varying degrees of disorder of the benzyl groups.« less

Alkyl Chain Length Dependent Structural and Orientational Transformations of Water at Alcohol-Water Interfaces and Its Relevance to Atmospheric Aerosols.

PubMed

Mondal, Jahur A; Namboodiri, V; Mathi, P; Singh, Ajay K

2017-04-06

Although the hydrophobic size of an amphiphile plays a key role in various chemical, biological, and atmospheric processes, its effect at macroscopic aqueous interfaces (e.g., air-water, oil-water, cell membrane-water, etc.), which are ubiquitous in nature, is not well understood. Here we report the hydrophobic alkyl chain length dependent structural and orientational transformations of water at alcohol (C n H 2n+1 OH, n = 1-12)-water interfaces using interface-selective heterodyne-detected vibrational sum frequency generation (HD-VSFG) and Raman multivariate curve resolution (Raman-MCR) spectroscopic techniques. The HD-VSFG results reveal that short-chain alcohols (C n H 2n+1 OH, n < 4, i.e., up to 1-propanol) do not affect the structure (H-bonding) and orientation of water at the air-water interface; the OH stretch band maximum appears at ∼3470 cm -1 , and the water H atoms are pointed toward the bulk water, that is, "H-down" oriented. In contrast, long-chain alcohols (C n H 2n+1 OH, n > 4, i.e., beyond 1-butanol) make the interfacial water more strongly H-bonded and reversely orientated; the OH stretch band maximum appears at ∼3200 cm -1 , and the H atoms are pointed away from the bulk water, that is, "H-up" oriented. Interestingly, for the alcohol of intermediate chain length (C n H 2n+1 OH, n = 4, i.e, 1-butanol), the interface is quite unstable even after hours of its formation and the time-averaged result is qualitatively similar to that of the long-chain alcohols, indicating a structural/orientational crossover of interfacial water at the 1-butanol-water interface. pH-dependent HD-VSFG measurements (with H 2 O as well as isotopically diluted water, HOD) suggest that the structural/orientational transformation of water at the long-chain alcohol-water interface is associated with the adsorption of OH - anion at the interface. Vibrational mapping of the water structure in the hydration shell of OH - anion (obtained by Raman-MCR spectroscopy of NaOH in HOD

Alcohols Reduce Lateral Membrane Pressures: Predictions from Molecular Theory

PubMed Central

Frischknecht, Amalie L.; Frink, Laura J. Douglas

2006-01-01

We explore the effects of alcohols on fluid lipid bilayers using a molecular theory with a coarse-grained model. We show that the trends predicted from the theory in the changes in area per lipid, alcohol concentration in the bilayer, and area compressibility modulus, as a function of alcohol chain length and of the alcohol concentration in the solvent far from the bilayer, follow those found experimentally. We then use the theory to study the effect of added alcohol on the lateral pressure profile across the membrane, and find that added alcohol reduces the surface tensions at both the headgroup/solvent and headgroup/tailgroup interfaces, as well as the lateral pressures in the headgroup and tailgroup regions. These changes in lateral pressures could affect the conformations of membrane proteins, providing a nonspecific mechanism for the biological effects of alcohols on cells. PMID:16980354

Field comparison of thermal and non-thermal ultra-low-volume applications using water and diesel as solvents for managing dengue vector, Aedes aegypti.

PubMed

Harburguer, Laura; Lucia, Alejandro; Licastro, Susana; Zerba, Eduardo; Masuh, Héctor

2012-10-01

To compare the effectiveness on Aedes aegypti (Linneo) (Diptera: Culicidae) of a larvicide-adulticide ULV formulation applied by a thermal or a cold fogger using different solvents. We applied, in field conditions, a ULV formulation containing pyriproxyfen and permethrin, using a thermal and a cold fogger and water or diesel as solvent. We determined the effectiveness of these applications on Ae. aegypti adults and larvae by different bioassays and measuring Breteau, house and adult indices. When water was used as solvent, the treatments applied with the cold or the thermal foggers were equally effective on adult mortality (close to 90%) and adult emergence inhibition (% EI) (close to 70%). When the thermal fogger was used with water as solvent, the adult mortality outside the houses (85%) was higher, but not significantly different, than with diesel (65%). The contrary happens inside (22%vs. 58%), while there were no differences in %EI. Adult and larval indices behaved similarly in all areas, with a slight tendency for the treatments applied using water as solvent to be more effective. Water-based formulations are equally or more effective than the one applied with diesel as solvent. The use of water as solvent will not only improve the effectiveness of this formulation but also reduce the environmental impact and costs of spraying compared to the use of diesel. © 2012 Blackwell Publishing Ltd.

Solvatochromic probe behavior within choline chloride-based deep eutectic solvents: effect of temperature and water.

PubMed

Pandey, Ashish; Pandey, Siddharth

2014-12-18

Deep eutectic solvents (DESs) have shown potential as promising environmentally friendly alternatives to conventional solvents. Many common and popular DESs are obtained by simply mixing a salt and a H-bond donor. Properties of such a DES depend on its constituents. Change in temperature and addition of water, a benign cosolvent, can change the physicochemical properties of DESs. The effect of changing temperature and addition of water on solvatochromic probe behavior within three DESs formed from choline chloride combined with 1,2-ethanediol, glycerol, and urea, respectively, in 1:2 mol ratios termed ethaline, glyceline, and reline is presented. Increase in temperature results in reduced H-bond donating acidity of the DESs. Dipolarity/polarizability and H-bond accepting basicity do not change with changing temperature of the DESs. The response of the fluorescence probe pyrene also indicates a decrease in the polarity of the DESs as temperature is increased. Addition of water to DES results in increased dipolarity/polarizability and a decrease in H-bond accepting basicity. Except for pyrene, solvatochromic probes exhibit responses close to those predicted from ideal-additive behavior with slight preferential solvation by DES within the aqueous mixtures. Pyrene response reveals significant preferential solvation by DES and/or the presence of solvent-solvent interactions, especially within aqueous mixtures of ethaline and glyceline, the DESs constituted of H-bond donors with hydroxyl functionalities. FTIR absorbance and Raman spectroscopic measurements of aqueous DES mixtures support the outcomes from solvatochromic probe responses. Aqueous mixtures of ethaline and glyceline possess relatively more interspecies H-bonds as compared to aqueous mixtures of reline, where interstitial accommodation of water within the reline molecular network appears to dominate.

Solvent fluctuations and nuclear quantum effects modulate the molecular hyperpolarizability of water

NASA Astrophysics Data System (ADS)

Liang, Chungwen; Tocci, Gabriele; Wilkins, David M.; Grisafi, Andrea; Roke, Sylvie; Ceriotti, Michele

2017-07-01

Second-harmonic scattering (SHS) experiments provide a unique approach to probe noncentrosymmetric environments in aqueous media, from bulk solutions to interfaces, living cells, and tissue. A central assumption made in analyzing SHS experiments is that each molecule scatters light according to a constant molecular hyperpolarizability tensor β(2 ). Here, we investigate the dependence of the molecular hyperpolarizability of water on its environment and internal geometric distortions, in order to test the hypothesis of constant β(2 ). We use quantum chemistry calculations of the hyperpolarizability of a molecule embedded in point-charge environments obtained from simulations of bulk water. We demonstrate that both the heterogeneity of the solvent configurations and the quantum mechanical fluctuations of the molecular geometry introduce large variations in the nonlinear optical response of water. This finding has the potential to change the way SHS experiments are interpreted: In particular, isotopic differences between H2O and D2O could explain recent SHS observations. Finally, we show that a machine-learning framework can predict accurately the fluctuations of the molecular hyperpolarizability. This model accounts for the microscopic inhomogeneity of the solvent and represents a step towards quantitative modeling of SHS experiments.

Fluorescence sensor for water in organic solvents prepared from covalent immobilization of 4-morpholinyl-1, 8-naphthalimide.

PubMed

Niu, Cheng-Gang; Qin, Pin-Zhu; Zeng, Guang-Ming; Gui, Xiao-Qin; Guan, Ai-Ling

2007-02-01

A new fluorescent dye, N-allyl-4-morpholinyl-1,8-naphthalimide (AMN), was synthesized as a fluorescence indicator in the fabrication of a sensor for determining water content in organic solvents. To prevent leakage of the fluorophore, AMN was photo-copolymerized with acrylamide, (2-hydroxyethyl)methacrylate, and triethylene glycol dimethacrylate on a glass surface treated with a silanizing agent. The sensing mechanism is based on the solvatochromic feature of the covalently immobilized AMN. The fluorescence intensity of AMN decreased with increasing water contents when it was excited at 400 nm. In the range of ca. 0.00-4.40% (v/v), the fluorescence intensity of AMN changed as a linear function of water content. The sensor exhibited satisfactory reproducibility, reversibility, and a response time (t (99)) of the order of 50 s. The detection limit was solvent-dependent, when acetonitrile was used as the solvent, and the detection limit could be as low as 0.006% (v/v) of water. Additionally, the prepared sensor is pH-insensitive and possesses a relatively long lifetime of at least one month.

NEPTUNIUM SOLVENT EXTRACTION PROCESS

DOEpatents

Dawson, L.R.; Fields, P.R.

1959-10-01

The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

Effects of pH changes in water-based solvents to isolate antibacterial activated extracts of natural products

NASA Astrophysics Data System (ADS)

Buang, Yohanes; Suwari, Ola, Antonius R. B.

2017-12-01

Effects of pH changes in solvents on isolation of antibacterial activities of natural product extracts were conducted in the present study. Sarang semut (M. pendens) tubers as the model material for the study was considered to be the strategic resource of natural products based on its biochemical and therapeutical effects. The water with pH 5, 7, 9, and 13 was used as the solvents. The antibacterial activities of the resulted extracts indicated that higher the working pH, higher activities of the resulted extracts. The extent activities of the resulted extracts followed the increasing pH of the maceration system. The study also found that higher pH of the working solvent, higher the amounts of the antibacterial extracts isolated from the sample matrix of the natural product. The higher pH of the water solvents plays essential roles to promote the antibacterial activities of the natural product extracts from M. pendens tubers.

Crystallization of perovskite film using ambient moisture and water as co-solvent for efficient planar perovskite solar cell (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dubey, Ashish; Reza, Khan M.; Gaml, Eman; Adhikari, Nirmal; Qiao, Qiquan

2016-09-01

Smooth, compact and defect free morphology of perovskite is highly desired for enhanced device performance. Several routes such as thermal annealing, use of solvent mixtures, growth under controlled humidity has been adopted to obtain crystalline, smooth and defect free perovskite film. Herein we showed direct use of water (H2O) as co-solvent in precursor solution and have optimized the water content required to obtain smooth and dense film. Varying concentration of water was used in precursor solution of CH3NH3I and PbI2 mixed in γ-butyrolactone (GBL) and dimethylsulfoxide (DMSO). Perovskite films were crystallized using toluene assisted solvent engineering method using GBL:DMSO:H2O as solvent mixture. The amount of water was varied from 1% to 25%, which resulted in change in film morphology and perovskite crystallinity. It was concluded that an appropriate amount of water is required to assist the crystallization process to obtain smooth pin-hole free morphology. The change in morphology led to improved fill factor in the device, with highest efficiency 14%, which was significantly higher than devices made from perovskite film without adding water. We also showed that addition of up to 25% by volume of water does not significantly change the device performance.

Biodiesel production from triolein and short chain alcohols through biocatalysis.

PubMed

Salis, Andrea; Pinna, Marcella; Monduzzi, Maura; Solinas, Vincenzo

2005-09-29

Oleic acid alkyl esters (biodiesel) were synthesised by biocatalysis in solvent-free conditions. Different commercial immobilised lipases, namely Candida antarctica B, Rizhomucor miehei, and Pseudomonas cepacia, were tested towards the reaction between triolein and butanol to produce butyl oleate. Pseudomonas cepacia lipase resulted to be the most active enzyme reaching 100% of conversion after 6h. Different operative conditions such as reaction temperature, water activity, and reagent stoichiometric ratio were investigated and optimised. These conditions were then used to investigate the effect of linear and branched short chain alcohols. Methanol and 2-butanol were the worst alcohols: the former, probably, due to its low miscibility with the oil and the latter because secondary alcohols usually are less reactive than primary alcohols. Conversely, linear and branched primary alcohols with short alkyl chains (C(2)--C(4)) showed high reaction rate and conversion. A mixture of linear and branched short chain alcohols that mimics the residual of ethanol distillation (fusel oil) was successfully used for oleic acid ester synthesis. These compounds are important in biodiesel mixtures since they improve low temperature properties.

Polarity control at interfaces: Quantifying pseudo-solvent effects in nano-confined systems

DOE PAGES

Singappuli-Arachchige, Dilini; Manzano, J. Sebastian; Sherman, Lindy M.; ...

2016-08-02

Surface functionalization controls local environments and induces solvent-like effects at liquid–solid interfaces. We explored structure–property relationships between organic groups bound to pore surfaces of mesoporous silica nanoparticles and Stokes shifts of the adsorbed solvatochromic dye Prodan. Correlating shifts of the dye on the surfaces with its shifts in solvents resulted in a local polarity scale for functionalized pores. The scale was validated by studying the effects of pore polarity on quenching of Nile Red fluorescence and on the vibronic band structure of pyrene. Measurements were done in aqueous suspensions of porous particles, proving that the dielectric properties in the poresmore » are different from the bulk solvent. The precise control of pore polarity was used to enhance the catalytic activity of TEMPO in the aerobic oxidation of furfuryl alcohol in water. Furthermore, an inverse relationship was found between pore polarity and activity of TEMPO in the pores, demonstrating that controlling the local polarity around an active site allows modulating the activity of nanoconfined catalysts.« less

Separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extraction

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

Ren, Shoujie; Ye, Philip; Borole, Abhijeet P

Bio-oil aqueous phase contains a considerable amount of furans, alcohols, ketones, aldehydes and phenolics besides the major components of organic acids and anhydrosugars. The complexity of bio-oil aqueous phase limits its efficient utilization. To improve the efficiency of bio-oil biorefinery, this study focused on the separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extractions. Due to their high recoverability and low solubility in water, four solvents (hexane, petroleum ether, chloroform, and ethyl acetate) with different polarities were evaluated, and the optimum process conditions for chemical extraction were determined. Chloroform had high extraction efficiency for furans, phenolics,more » and ketones. In addition to these chemical groups, ethyl acetate had high extraction efficiency for organic acids. The sequential extraction by using chloroform followed by ethyl acetate rendered that 62.2 wt.% of original furans, ketones, alcohols, and phenolics were extracted to chloroform, over 62 wt.% acetic acid was extracted to ethyl acetate, resulting in a high concentration of levoglucosan (~53.0 wt.%) in the final aqueous phase. Chemicals separated via the sequential extraction could be used as feedstocks in biorefinery using processes such as catalytic upgrading of furans and phenolics to hydrocarbons, fermentation of levoglucosan to produce alcohols and diols, and hydrogen production from organic acids via microbial electrolysis.« less

Separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extraction

DOE PAGES

Ren, Shoujie; Ye, Philip; Borole, Abhijeet P

2017-01-05

Bio-oil aqueous phase contains a considerable amount of furans, alcohols, ketones, aldehydes and phenolics besides the major components of organic acids and anhydrosugars. The complexity of bio-oil aqueous phase limits its efficient utilization. To improve the efficiency of bio-oil biorefinery, this study focused on the separation of chemical groups from bio-oil aqueous phase via sequential organic solvent extractions. Due to their high recoverability and low solubility in water, four solvents (hexane, petroleum ether, chloroform, and ethyl acetate) with different polarities were evaluated, and the optimum process conditions for chemical extraction were determined. Chloroform had high extraction efficiency for furans, phenolics,more » and ketones. In addition to these chemical groups, ethyl acetate had high extraction efficiency for organic acids. The sequential extraction by using chloroform followed by ethyl acetate rendered that 62.2 wt.% of original furans, ketones, alcohols, and phenolics were extracted to chloroform, over 62 wt.% acetic acid was extracted to ethyl acetate, resulting in a high concentration of levoglucosan (~53.0 wt.%) in the final aqueous phase. Chemicals separated via the sequential extraction could be used as feedstocks in biorefinery using processes such as catalytic upgrading of furans and phenolics to hydrocarbons, fermentation of levoglucosan to produce alcohols and diols, and hydrogen production from organic acids via microbial electrolysis.« less

The Role of Interfacial Water in Protein-Ligand Binding: Insights from the Indirect Solvent Mediated Potential of Mean Force.

PubMed

Cui, Di; Zhang, Bin W; Matubayasi, Nobuyuki; Levy, Ronald M

2018-02-13

Classical density functional theory (DFT) can be used to relate the thermodynamic properties of solutions to the indirect solvent mediated part of the solute-solvent potential of mean force (PMF). Standard, but powerful numerical methods can be used to estimate the solute-solvent PMF from which the indirect part can be extracted. In this work we show how knowledge of the direct and indirect parts of the solute-solvent PMF for water at the interface of a protein receptor can be used to gain insights about how to design tighter binding ligands. As we show, the indirect part of the solute-solvent PMF is equal to the sum of the 1-body (energy + entropy) terms in the inhomogeneous solvation theory (IST) expansion of the solvation free energy. To illustrate the effect of displacing interfacial water molecules with particular direct/indirect PMF signatures on the binding of ligands, we carry out simulations of protein binding with several pairs of congeneric ligands. We show that interfacial water locations that contribute favorably or unfavorably at the 1-body level (energy + entropy) to the solvation free energy of the solute can be targeted as part of the ligand design process. Water locations where the indirect PMF is larger in magnitude provide better targets for displacement when adding a functional group to a ligand core.

Chemoselective formation of unsymmetrically substituted ethers from catalytic reductive coupling of aldehydes and ketones with alcohols in aqueous solution.

PubMed

Kalutharage, Nishantha; Yi, Chae S

2015-04-03

A well-defined cationic Ru-H complex catalyzes reductive etherification of aldehydes and ketones with alcohols. The catalytic method employs environmentally benign water as the solvent and cheaply available molecular hydrogen as the reducing agent to afford unsymmetrical ethers in a highly chemoselective manner.

RELATIONSHIP BETWEEN DEHALOCOCCOIDES DNA IN GROUND WATER AND NATURAL ATTENUATION OF CHLORINATED SOLVENTS

EPA Science Inventory

Biological reductive dechlorination is the primary mechanism for natural attenuation of chlorinated solvents in ground water. The only organisms that are known to completely dechlorinate cis-DCE past vinyl chloride to ethylene or ethane are members of the Dehalococcoides group. ...

Direct α-alkylation of ketones with alcohols in water.

PubMed

Xu, Guoqiang; Li, Qiong; Feng, Jiange; Liu, Qiang; Zhang, Zuojun; Wang, Xicheng; Zhang, Xiaoyun; Mu, Xindong

2014-01-01

The direct α-alkylation of ketones with alcohols has emerged as a new green protocol to construct C-C bonds with H2 O as the sole byproduct. In this work, a very simple and convenient Pd/C catalytic system for the direct α-alkylation of ketones with primary alcohols in pure water is developed. Based on this catalytic system, aqueous mixtures of dilute acetone, 1-butanol, and ethanol (mimicking ABE fermentation products) can be directly transformed into C5 -C11 or longer-chain ketones and alcohols, which are precursors to fuels. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ligand-Substitution Reactions of the Tellurium Compound AS-101 in Physiological Aqueous and Alcoholic Solutions.

PubMed

Silberman, Alon; Albeck, Michael; Sredni, Benjamin; Albeck, Amnon

2016-11-07

Since its first crystallization, the aqueous structure of the tellurium-containing experimental drug AS-101 has never been studied. We show that, under the aqueous conditions in which it is administered, AS-101 is subjected to an immediate ligand-substitution reaction with water, yielding a stable hydrolyzed oxide anion product that is identified, for the first time, to be TeOCl 3 - . Studying the structure of AS-101 in propylene glycol (PG), an alcoholic solvent often used for the topical and oral administration of AS-101, revealed the same phenomenon of ligand-substitution reaction between the alcoholic ligands. Upon exposure to water, the PG-substituted product is also hydrolyzed to the same tellurium(IV) oxide form, TeOCl 3 - .

Extracting organic matter on Mars: A comparison of methods involving subcritical water, surfactant solutions and organic solvents

NASA Astrophysics Data System (ADS)

Luong, Duy; Court, Richard W.; Sims, Mark R.; Cullen, David C.; Sephton, Mark A.

2014-09-01

The first step in many life detection protocols on Mars involves attempts to extract or isolate organic matter from its mineral matrix. A number of extraction options are available and include heat and solvent assisted methods. Recent operations on Mars indicate that heating samples can cause the loss or obfuscation of organic signals from target materials, raising the importance of solvent-based systems for future missions. Several solvent types are available (e.g. organic solvents, surfactant based solvents and subcritical water extraction) but a comparison of their efficiencies in Mars relevant materials is missing. We have spiked the well characterised Mars analogue material JSC Mars-1 with a number of representative organic standards. Extraction of the spiked JSC Mars-1 with the three solvent methods provides insights into the relative efficiency of these methods and indicates how they may be used on future Mars missions.

Inhibition of MMPs by alcohols

PubMed Central

Tezvergil-Mutluay, Arzu; Agee, Kelli A.; Hoshika, Tomohiro; Uchiyama, Toshikazu; Tjäderhane, Leo; Breschi, Lorenzo; Mazzoni, Annalisa; Thompson, Jeremy M.; McCracken, Courtney E.; Looney, Stephen W.; Tay, Franklin R.; Pashley, David H.

2011-01-01

Objectives While screening the activity of potential inhibitors of matrix metalloproteinases (MMPs), due to the limited water solubility of some of the compounds, they had to be solubilized in ethanol. When ethanol solvent controls were run, they were found to partially inhibit MMPs. Thus, the purpose of this study was to compare the MMP-inhibitory activity of a series of alcohols. Methods The possible inhibitory activity of a series of alcohols was measured against soluble rhMMP-9 and insoluble matrix-bound endogenous MMPs of dentin in completely demineralized dentin. Increasing concentrations (0.17, 0.86, 1.71 and 4.28 moles/L) of a homologous series of alcohols (i.e. methanol, ethanol, propanols, butanols, pentanols, hexanols, the ethanol ester of methacrylic acid, heptanols and octanol) were compared to ethanediol, and propanediol by regression analysis to calculate the molar concentration required to inhibit MMPs by 50% (i.e. the IC50). Results Using two different MMP models, alcohols were shown to inhibit rhMMP-9 and the endogenous proteases of dentin matrix in a dose-dependent manner. The degree of MMP inhibition by alcohols increased with chain length up to 4 methylene groups. Based on the molar concentration required to inhibit rhMMP-9 fifty percent, 2-hydroxyethylmethacrylate (HEMA), 3-hexanol, 3-heptanol and 1-octanol gave the strongest inhibition. Significance The results indicate that alcohols with 4 methylene groups inhibit MMPs more effectively than methanol or ethanol. MMP inhibition was inversely related to the Hoy's solubility parameter for hydrogen bonding forces of the alcohols (i.e. to their hydrophilicity). PMID:21676453

40 CFR 148.10 - Waste specific prohibitions-solvent wastes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Waste specific prohibitions-solvent wastes. 148.10 Section 148.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER... injection unless the solvent waste is a solvent-water mixture or solvent-containing sludge containing less...

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.

Comparison of polymer induced and solvent induced trypsin denaturation: the role of hydrophobicity.

PubMed

Jasti, Lakshmi S; Fadnavis, Nitin W; Addepally, Uma; Daniels, Siona; Deokar, Sarika; Ponrathnam, Surendra

2014-04-01

Trypsin adsorption from aqueous buffer by various copolymers of allyl glycidyl ether-ethylene glycol dimethacrylate (AGE-EGDM) copolymer with varying crosslink density increases with increasing crosslink density and the effect slowly wears off after reaching a plateau at 50% crosslink density. The copolymer with 25% crosslink density was reacted with different amines with alkyl/aryl side chains to obtain a series of copolymers with 1,2-amino alcohol functional groups and varying hydrophobicity. Trypsin binding capacity again increases with hydrophobicity of the reacting amine and a good correlation between logPoctanol of the amine and protein binding is observed. The bound trypsin is denatured to the extent of 90% in spite of the presence of hydrophilic hydroxyl and amino groups. The behavior was comparable to that in mixtures of aqueous buffer and water-miscible organic co-solvents where the solvent concentration required to deactivate 50% of the enzyme (C50) is dependent on logPoctanol of the co-solvent. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantum Chemically Estimated Abraham Solute Parameters Using Multiple Solvent-Water Partition Coefficients and Molecular Polarizability.

PubMed

Liang, Yuzhen; Xiong, Ruichang; Sandler, Stanley I; Di Toro, Dominic M

2017-09-05

Polyparameter Linear Free Energy Relationships (pp-LFERs), also called Linear Solvation Energy Relationships (LSERs), are used to predict many environmentally significant properties of chemicals. A method is presented for computing the necessary chemical parameters, the Abraham parameters (AP), used by many pp-LFERs. It employs quantum chemical calculations and uses only the chemical's molecular structure. The method computes the Abraham E parameter using density functional theory computed molecular polarizability and the Clausius-Mossotti equation relating the index refraction to the molecular polarizability, estimates the Abraham V as the COSMO calculated molecular volume, and computes the remaining AP S, A, and B jointly with a multiple linear regression using sixty-five solvent-water partition coefficients computed using the quantum mechanical COSMO-SAC solvation model. These solute parameters, referred to as Quantum Chemically estimated Abraham Parameters (QCAP), are further adjusted by fitting to experimentally based APs using QCAP parameters as the independent variables so that they are compatible with existing Abraham pp-LFERs. QCAP and adjusted QCAP for 1827 neutral chemicals are included. For 24 solvent-water systems including octanol-water, predicted log solvent-water partition coefficients using adjusted QCAP have the smallest root-mean-square errors (RMSEs, 0.314-0.602) compared to predictions made using APs estimated using the molecular fragment based method ABSOLV (0.45-0.716). For munition and munition-like compounds, adjusted QCAP has much lower RMSE (0.860) than does ABSOLV (4.45) which essentially fails for these compounds.

Electro-driven extraction of inorganic anions from water samples and water miscible organic solvents and analysis by ion chromatography.

PubMed

Nojavan, Saeed; Bidarmanesh, Tina; Memarzadeh, Farkhondeh; Chalavi, Soheila

2014-09-01

A simple electromembrane extraction (EME) procedure combined with ion chromatography (IC) was developed to quantify inorganic anions in different pure water samples and water miscible organic solvents. The parameters affecting extraction performance, such as supported liquid membrane (SLM) solvent, extraction time, pH of donor and acceptor solutions, and extraction voltage were optimized. The optimized EME conditions were as follows: 1-heptanol was used as the SLM solvent, the extraction time was 10 min, pHs of the acceptor and donor solutions were 10 and 7, respectively, and the extraction voltage was 15 V. The mobile phase used for IC was a combination of 1.8 mM sodium carbonate and 1.7 mM sodium bicarbonate. Under these optimized conditions, all anions had enrichment factors ranging from 67 to 117 with RSDs between 7.3 and 13.5% (n = 5). Good linearity values ranging from 2 to 1200 ng/mL with coefficients of determination (R(2) ) between 0.987 and 0.999 were obtained. The LODs of the EME-IC method ranged from 0.6 to 7.5 ng/mL. The developed method was applied to different samples to evaluate the feasibility of the method for real applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water dynamics in small reverse micelles in two solvents: two-dimensional infrared vibrational echoes with two-dimensional background subtraction.

PubMed

Fenn, Emily E; Wong, Daryl B; Fayer, M D

2011-02-07

Water dynamics as reflected by the spectral diffusion of the water hydroxyl stretch were measured in w(0) = 2 (1.7 nm diameter) Aerosol-OT (AOT)/water reverse micelles in carbon tetrachloride and in isooctane solvents using ultrafast 2D IR vibrational echo spectroscopy. Orientational relaxation and population relaxation are observed for w(0) = 2, 4, and 7.5 in both solvents using IR pump-probe measurements. It is found that the pump-probe observables are sensitive to w(0), but not to the solvent. However, initial analysis of the vibrational echo data from the water nanopool in the reverse micelles in the isooctane solvent seems to yield different dynamics than the CCl(4) system in spite of the fact that the spectra, vibrational lifetimes, and orientational relaxation are the same in the two systems. It is found that there are beat patterns in the interferograms with isooctane as the solvent. The beats are observed from a signal generated by the AOT/isooctane system even when there is no water in the system. A beat subtraction data processing procedure does a reasonable job of removing the distortions in the isooctane data, showing that the reverse micelle dynamics are the same within experimental error regardless of whether isooctane or carbon tetrachloride is used as the organic phase. Two time scales are observed in the vibrational echo data, ~1 and ~10 ps. The slower component contains a significant amount of the total inhomogeneous broadening. Physical arguments indicate that there is a much slower component of spectral diffusion that is too slow to observe within the experimental window, which is limited by the OD stretch vibrational lifetime.

Water dynamics in small reverse micelles in two solvents: Two-dimensional infrared vibrational echoes with two-dimensional background subtraction

NASA Astrophysics Data System (ADS)

Fenn, Emily E.; Wong, Daryl B.; Fayer, M. D.

2011-02-01

Water dynamics as reflected by the spectral diffusion of the water hydroxyl stretch were measured in w0 = 2 (1.7 nm diameter) Aerosol-OT (AOT)/water reverse micelles in carbon tetrachloride and in isooctane solvents using ultrafast 2D IR vibrational echo spectroscopy. Orientational relaxation and population relaxation are observed for w0 = 2, 4, and 7.5 in both solvents using IR pump-probe measurements. It is found that the pump-probe observables are sensitive to w0, but not to the solvent. However, initial analysis of the vibrational echo data from the water nanopool in the reverse micelles in the isooctane solvent seems to yield different dynamics than the CCl4 system in spite of the fact that the spectra, vibrational lifetimes, and orientational relaxation are the same in the two systems. It is found that there are beat patterns in the interferograms with isooctane as the solvent. The beats are observed from a signal generated by the AOT/isooctane system even when there is no water in the system. A beat subtraction data processing procedure does a reasonable job of removing the distortions in the isooctane data, showing that the reverse micelle dynamics are the same within experimental error regardless of whether isooctane or carbon tetrachloride is used as the organic phase. Two time scales are observed in the vibrational echo data, ~1 and ~10 ps. The slower component contains a significant amount of the total inhomogeneous broadening. Physical arguments indicate that there is a much slower component of spectral diffusion that is too slow to observe within the experimental window, which is limited by the OD stretch vibrational lifetime.

The Denaturation Transition of DNA in Mixed Solvents

PubMed Central

Hammouda, Boualem; Worcester, David

2006-01-01

The helix-to-coil denaturation transition in DNA has been investigated in mixed solvents at high concentration using ultraviolet light absorption spectroscopy and small-angle neutron scattering. Two solvents have been used: water and ethylene glycol. The “melting” transition temperature was found to be 94°C for 4% mass fraction DNA/d-water and 38°C for 4% mass fraction DNA/d-ethylene glycol. The DNA melting transition temperature was found to vary linearly with the solvent fraction in the mixed solvents case. Deuterated solvents (d-water and d-ethylene glycol) were used to enhance the small-angle neutron scattering signal and 0.1M NaCl (or 0.0058 g/g mass fraction) salt concentration was added to screen charge interactions in all cases. DNA structural information was obtained by small-angle neutron scattering, including a correlation length characteristic of the inter-distance between the hydrogen-containing (desoxyribose sugar-amine base) groups. This correlation length was found to increase from 8.5 to 12.3 Å across the melting transition. Ethylene glycol and water mixed solvents were found to mix randomly in the solvation region in the helix phase, but nonideal solvent mixing was found in the melted coil phase. In the coil phase, solvent mixtures are more effective solvating agents than either of the individual solvents. Once melted, DNA coils behave like swollen water-soluble synthetic polymer chains. PMID:16815902

[Effects of snow cover on water soluble and organic solvent soluble components during foliar litter decomposition in an alpine forest].

PubMed

Xu, Li-Ya; Yang, Wan-Qin; Li, Han; Ni, Xiang-Yin; He, Jie; Wu, Fu-Zhong

2014-11-01

Seasonal snow cover may change the characteristics of freezing, leaching and freeze-thaw cycles in the scenario of climate change, and then play important roles in the dynamics of water soluble and organic solvent soluble components during foliar litter decomposition in the alpine forest. Therefore, a field litterbag experiment was conducted in an alpine forest in western Sichuan, China. The foliar litterbags of typical tree species (birch, cypress, larch and fir) and shrub species (willow and azalea) were placed on the forest floor under different snow cover thickness (deep snow, medium snow, thin snow and no snow). The litterbags were sampled at snow formation stage, snow cover stage and snow melting stage in winter. The results showed that the content of water soluble components from six foliar litters decreased at snow formation stage and snow melting stage, but increased at snow cover stage as litter decomposition proceeded in the winter. Besides the content of organic solvent soluble components from azalea foliar litter increased at snow cover stage, the content of organic solvent soluble components from the other five foliar litters kept a continue decreasing tendency in the winter. Compared with the content of organic solvent soluble components, the content of water soluble components was affected more strongly by snow cover thickness, especially at snow formation stage and snow cover stage. Compared with the thicker snow covers, the thin snow cover promoted the decrease of water soluble component contents from willow and azalea foliar litter and restrain the decrease of water soluble component content from cypress foliar litter. Few changes in the content of water soluble components from birch, fir and larch foliar litter were observed under the different thicknesses of snow cover. The results suggested that the effects of snow cover on the contents of water soluble and organic solvent soluble components during litter decomposition would be controlled by

Inert Reassessment Document for Ethyl Alcohol - CAS No. 64-17-5

EPA Pesticide Factsheets

The main use of ethyl alcohol is in the consumption of alcoholic beverage and as a solvent in the laboratory and industry, and in the manufacture of denatured alcohol, pharmaceuticals, perfumes, and organic synthesis.

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.

Enhanced Furfural Yields from Xylose Dehydration in the gamma-Valerolactone/Water Solvent System at Elevated Temperatures.

PubMed

Sener, Canan; Motagamwala, Ali Hussain; Alonso, David Martin; Dumesic, James

2018-05-18

High yields of furfural (>90%) were achieved from xylose dehydration in a sustainable solvent system composed of -valerolactone (GVL), a biomass derived solvent, and water. It is identified that high reaction temperatures (e.g., 498 K) are required to achieve high furfural yield. Additionally, it is shown that the furfural yield at these temperatures is independent of the initial xylose concentration, and high furfural yield is obtained for industrially relevant xylose concentrations (10 wt%). A reaction kinetics model is developed to describe the experimental data obtained with solvent system composed of 80 wt% GVL and 20 wt% water across the range of reaction conditions studied (473 - 523 K, 1-10 mM acid catalyst, 66 - 660 mM xylose concentration). The kinetic model demonstrates that furfural loss due to bimolecular condensation of xylose and furfural is minimized at elevated temperature, whereas carbon loss due to xylose degradation increases with increasing temperature. Accordingly, the optimal temperature range for xylose dehydration to furfural in the GVL/H2O solvent system is identified to be from 480 to 500 K. Under these reaction conditions, furfural yield of 93% is achieved at 97% xylan conversion from lignocellulosic biomass (maple wood). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid-liquid extraction of ethanol from aqueous solutions with amyl acetate, benzyl alcohol, and methyl isobutyl ketone at 298. 15. Kappa

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

Solimo, H.N.; Martinez, H.E.; Riggio, R.

1989-04-01

Experimental mutual solubility and tie-line data were determined for three ternary liquid-liquid systems containing water, ethanol, and amyl acetate, benzyl alcohol, and methyl isobutyl ketone at 298.15{Kappa} in order to obtain their complete phase diagrams and to determine which is the most suitable solvent for extraction of ethanol from aqueous solutions. Tie lines were determined correlating the density of the binodal curve as a function of composition and the plait points using the Othmer and Tobias method. The experimental data were also correlated with the UNIFAC group contribution method. A qualitative agreement was obtained. Experimental results show that amyl acetatemore » is a better solvent than methyl isobutyl ketone and benzyl alcohol.« less

The solvation of L-serine in mixtures of water with some aprotic solvents at 298.15 K

NASA Astrophysics Data System (ADS)

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

2009-03-01

The integral enthalpies of solution Δsol H m of L-serine in mixtures of water with acetonitrile, 1,4-dioxane, dimethylsulfoxide (DMSO), and acetone were measured by solution calorimetry at organic component concentrations up to 0.31 mole fractions. The standard enthalpies of solution (Δsol H°), transfer (Δtr H°), and solvation (Δsolv H°) of L-serine from water into mixed solvents were calculated. The dependences of Δsol H°, Δsolv H°, and Δtr H° on the composition of aqueous-organic solvents contained extrema. The calculated enthalpy coefficients of pair interactions of the amino acid with cosolvent molecules were positive and increased in the series acetonitrile, 1,4-dioxane, DMSO, acetone. The results obtained were interpreted from the point of view of various types of interactions in solutions and the influence of the nature of organic solvents on the thermochemical characteristics of solutions.

Preparation of high-aspect-ratio ZnO nanorod arrays for the detection of several organic solvents at room working temperature

NASA Astrophysics Data System (ADS)

Lee, Yi-Mu; Zheng, Min-Ren

2013-11-01

Chemical sensors based on ZnO nanorod arrays were prepared using chemical bath deposition (CBD) to investigate the sensing performance for the detection of several organic solvents with low concentrations (0.1%, 0.5%, 1%, v/v) at room temperature. High quality and high aspect-ratio (value ˜28) ZnO nanorods have a diameter of about 74 nm and average length of 2.1 μm. Nyquist plots and Bode plots of the ZnO sensors under different organic solvents were obtained by electrical impedance spectroscopy (EIS). The sensing properties such as charge-transfer resistance, double-layer capacitance and dielectric parameters were determined from the impedance spectra to explore the charge transport in low-concentration aqueous solutions. The decreasing trend of the charge-transfer resistance (Rct) as decreasing solvent concentrations is observed, and a straight line at low frequency regime indicates adsorption of water molecules on the oxide surface. The sensitivity of the ZnO sensors was calculated from the resistance variation in target solvents and in deionized water. We demonstrated the use of ZnO nanorod arrays as a chemical sensor capable of generating a different response upon exposure to methanol, ethanol, isopropyl alcohol, acetone and water, wherein the methanol sensing exhibited highest sensitivity. In addition, the ZnO sensor also demonstrates good stability and reproducibility for detection of methanol and ethanol.

Physicochemical properties of valsartan and the effect of ethyl alcohol, propylene glycol and pH on its solubility.

PubMed

Mbah, C J

2005-11-01

The aqueous solubility and partition coefficient of valsartan were determined at room temperature. The effect of ethyl alcohol, propylene glycol and pH on its solubility was also investigated. It was found that both solvents increased the solubility of the drug in water. The solubilizing power of ethyl alcohol was found to be higher than that of propylene glycol. Valsartan solubility was also observed to increase at high pH values and its lipophilicity wasdemonstrated by the high positive value of the logarithm of partition coefficient.

Solvent tuning configurational conversion of lycopene aggregates in organic-aqueous mixing solvent

NASA Astrophysics Data System (ADS)

Dong, Jia; Zhang, Di; Wang, Xin-Yue; Wang, Peng

2018-06-01

In general cases, carotenoid aggregates are prepared in organic-water mixing solvent depending on its hydrophobic character. It is well-known that one of carotenoids, lycopene, is more likely to form typical H-aggregates. In this study, new type lycopene J-aggregates were prepared in DMSO-water mixing solvent with small amount of toluene, which was observed for the first time. We proposed a potential structure model combining with exciton model to interpret the mechanism of spectra changes. Our finding has provided new methods and novel ideas for controlling carotenoid aggregates formation.

Unified scaling behavior of physical properties of clays in alcohol solutions.

PubMed

Pujala, Ravi Kumar; Pawar, Nisha; Bohidar, H B

2011-12-15

This paper reports observation of universal scaling of physical properties of clay particles, Laponite (aspect ratio=30) (L) and Na Montmorillonite (MMT, aspect ratio=200), in aqueous alcohol solutions (methanol, ethanol and 1-propanol) with solvent polarity, defined through reaction field factor f(OH)(ɛ(0),n)=[(ɛ(0) - 1/ɛ(0) + 2) - (n(2) - 1/n(2) + 2)], at room temperature (20°C). Here, ɛ(0) and n are the static dielectric constant and refractive index of the solvent concerned. Physical properties (Z) such as zeta potential, effective aggregate size, viscosity and surface tension scaled with the relative solvent polarity as Z∼δf(α); δf=(f(w)(ɛ(0),n) - f(OH)(ɛ(0),n)), where f(w)(ɛ(0),n) is the reaction field factor for water, Z is the normalized physical property, and α is its characteristic scaling exponent. The value of this exponent was found to be invariant of aspect ratio of the clay but dependent on the solvent polarity only. Copyright © 2011 Elsevier Inc. All rights reserved.

The structure of graphene oxide membranes in liquid water, ethanol and water-ethanol mixtures

NASA Astrophysics Data System (ADS)

Talyzin, Alexandr V.; Hausmaninger, Tomas; You, Shujie; Szabó, Tamás

2013-12-01

The structure of graphene oxide (GO) membranes was studied in situ in liquid solvents using synchrotron radiation X-ray diffraction in a broad temperature interval. GO membranes are hydrated by water similarly to precursor graphite oxide powders but intercalation of alcohols is strongly hindered, which explains why the GO membranes are permeated by water and not by ethanol. Insertion of ethanol into the membrane structure is limited to only one monolayer in the whole studied temperature range, in contrast to precursor graphite oxide powders, which are intercalated with up to two ethanol monolayers (Brodie) and four ethanol monolayers (Hummers). As a result, GO membranes demonstrate the absence of ``negative thermal expansion'' and phase transitions connected to insertion/de-insertion of alcohols upon temperature variations reported earlier for graphite oxide powders. Therefore, GO membranes are a distinct type of material with unique solvation properties compared to parent graphite oxides even if they are composed of the same graphene oxide flakes.The structure of graphene oxide (GO) membranes was studied in situ in liquid solvents using synchrotron radiation X-ray diffraction in a broad temperature interval. GO membranes are hydrated by water similarly to precursor graphite oxide powders but intercalation of alcohols is strongly hindered, which explains why the GO membranes are permeated by water and not by ethanol. Insertion of ethanol into the membrane structure is limited to only one monolayer in the whole studied temperature range, in contrast to precursor graphite oxide powders, which are intercalated with up to two ethanol monolayers (Brodie) and four ethanol monolayers (Hummers). As a result, GO membranes demonstrate the absence of ``negative thermal expansion'' and phase transitions connected to insertion/de-insertion of alcohols upon temperature variations reported earlier for graphite oxide powders. Therefore, GO membranes are a distinct type of material

Antimicrobial efficacy of soap and water hand washing versus an alcohol-based hand cleanser.

PubMed

Holton, Ronald H; Huber, Michaell A; Terezhalmy, Geza T

2009-12-01

The emergence of alcohol-based hand cleansers may represent an alternative to soap and water in the clinical dental setting. In this study, the antimicrobial efficacy of traditional hand washing vs. a unique alcohol-based hand cleanser with persistence was evaluated. Two experienced dentists participated over a 10-day period. On days 1-5, each clinician used an antibacterial liquid soap (Dial, Dial Corporation, Scottsdale, AZ). Days 6-10, an alcohol-based hand cleanser (Triseptin Water Optional, Healthpoint Surgical, Fort Worth, TX) was used. Sampling was by modified glove juice technique. The results indicate that the alcohol-based hand cleanser dramatically outperforms the traditional hand washing agent in the general dental setting.

Predicting Displaceable Water Sites Using Mixed-Solvent Molecular Dynamics.

PubMed

Graham, Sarah E; Smith, Richard D; Carlson, Heather A

2018-02-26

Water molecules are an important factor in protein-ligand binding. Upon binding of a ligand with a protein's surface, waters can either be displaced by the ligand or may be conserved and possibly bridge interactions between the protein and ligand. Depending on the specific interactions made by the ligand, displacing waters can yield a gain in binding affinity. The extent to which binding affinity may increase is difficult to predict, as the favorable displacement of a water molecule is dependent on the site-specific interactions made by the water and the potential ligand. Several methods have been developed to predict the location of water sites on a protein's surface, but the majority of methods are not able to take into account both protein dynamics and the interactions made by specific functional groups. Mixed-solvent molecular dynamics (MixMD) is a cosolvent simulation technique that explicitly accounts for the interaction of both water and small molecule probes with a protein's surface, allowing for their direct competition. This method has previously been shown to identify both active and allosteric sites on a protein's surface. Using a test set of eight systems, we have developed a method using MixMD to identify conserved and displaceable water sites. Conserved sites can be determined by an occupancy-based metric to identify sites which are consistently occupied by water even in the presence of probe molecules. Conversely, displaceable water sites can be found by considering the sites which preferentially bind probe molecules. Furthermore, the inclusion of six probe types allows the MixMD method to predict which functional groups are capable of displacing which water sites. The MixMD method consistently identifies sites which are likely to be nondisplaceable and predicts the favorable displacement of water sites that are known to be displaced upon ligand binding.

Low-Pressure Alcohol Distillation

NASA Technical Reports Server (NTRS)

Frazier, D. O.; Zur Burg, F. W.; Cody, J. C.

1984-01-01

Heat requirements lowered for process. Temperature requirements lowered enough to make solar heat absorbed by flat-plate collectors feasible energy source. Alcohol produced without adding other solvents, eliminating need for dehydration or hydrocarbon stripping as final step.

Gibbs energies of transferring triglycine from water into H2O-DMSO solvent

NASA Astrophysics Data System (ADS)

Usacheva, T. R.; Kuz'mina, K. I.; Lan, Pham Thi; Kuz'mina, I. A.; Sharnin, V. A.

2014-08-01

The Gibbs energies of transferring triglycine (3Gly, glycyl-glycyl-glycine) from water into mixtures of water with dimethyl sulfoxide (χDMSO = 0.05, 0.10, and 0.15 mole fractions) at 298.15 K are determined from the interphase distribution. An increased dimethyl sulfoxide (DMSO) concentration in the solvent slightly raises the positive values of Δtr G ○(3Gly), possibly indicating the formation of more stable 3Gly-H2O solvated complexes than ones of 3Gly-DMSO. It is shown that the change in the Gibbs energy of transfer of 3Gly is determined by the enthalpy component. The relationship of 3Gly and 18-crown-6 ether (18C6) solvation's contributions to the change in the Gibbs energy of [3Gly18C6] molecular complex formation in H2O-DMSO solvents is analyzed, and the key role of 3Gly solvation's contribution to the change in the stability of [3Gly18C6] upon moving from H2O to mixtures with DMSO is revealed.

Methyltrioxorhenium-catalyzed epoxidation of homoallylic alcohols with hydrogen peroxide.

PubMed

Yamazaki, Shigekazu

2012-11-02

Homoallylic alcohols were efficiently converted to the corresponding 3,4-epoxy alcohols in excellent yields by methyltrioxorhenium (MTO)-catalyzed epoxidation with aqueous hydrogen peroxide as the terminal oxidant and 3-methylpyrazole (10 mol %) as an additive. The epoxidations of homoallylic alcohols proceeded under organic solvent-free conditions faster than those in dichloromethane.

Effect of chain structure on hydrogen bonding in vinyl acetate - vinyl alcohol copolymers

NASA Astrophysics Data System (ADS)

Merekalova, Nadezhda D.; Bondarenko, Galina N.; Denisova, Yuliya I.; Krentsel, Liya B.; Litmanovich, Arkadiy D.; Kudryavtsev, Yaroslav V.

2017-04-01

FTIR spectroscopy and semi-empirical AM1 method are used to study hydrogen bonding in multiblock and random equimolar copolymers of vinyl acetate and vinyl alcohol. An energetically beneficial zip-holder complex, built on multiple inter- and intrachain hydroxyl-hydroxyl bonds and an intrachain hydroxyl-acetyloxy bond, can be formed between two vinyl alcohol sequences. As a result, multiblock copolymers reveal stronger degree of association that affects crystallinity, as well as various rheological and relaxation properties discussed in the literature. Macromolecular complexes in random copolymers are weak and tend to be destroyed in the presence of residual DMF solvent and adsorbed water. Nevertheless, a rather stable interchain quaternary complex can be formed that includes vinyl alcohol and vinyl acetate units and DMF and water molecules. For a single chain it is shown that an H-bond between neighboring vinyl alcohol and vinyl acetate monomer units mostly engages a carbonyl oxygen atom of the vinyl acetate, if the vinyl alcohol belongs to a short (<5 units) sequence, and an ether oxygen atom in the other case. On the whole, the quantum chemistry calculations shed much light on the origin of distinctions in the copolymer FTIR spectra, which may seem subtle when considered standalone.

Immunomodulatory activities of different solvent extracts from Tricholoma matsutake (S. Ito et S. Imai) singer (higher basidiomycetes) on normal mice.

PubMed

Yin, Xiulian; You, Qinghong; Jiang, Zhonghai

2012-01-01

The immunomodulatory activities of different solvent extracts from the culinary-medicinal mushroom Tricholoma matsutake were studied in vivo in normal mice. The extracts were prepared using different solvents in an order of increasing polarity. The immunomodulatory activities were investigated by measuring the thymus and spleen index, phagocytic rate of macrophage phagocytosis, delayed-type hypersensitivity, plaque-forming cell, and proliferation of splenocytes. Results demonstrated that water extract (WE) and n-butyl alcohol extract (BAE) of T. matsutake could enhance the immunity of mice significantly compared with the control group. Main components of WE and BAE were polysaccharides, proteins, and flavonoids; we presume that these may be the main immunomodulating and immuno-enhancing agents in T. matsutake.

Comparison of the exposure-excretion relationship between men and women exposed to organic solvents.

PubMed

Kawai, Toshio; Takeuchi, Akito; Ikeda, Masayuki

2015-01-01

The present study was initiated to examine if application of the same biological occupational exposure limits (BOELs) for organic solvents is applicable across the sexes. A survey was conducted in 69 micro-scale enterprises in a furniture-producing industrial park. In practice, 211 men and 52 women participated in the survey. They worked in a series of production process, and were exposed to solvent vapor mixtures. The exposure intensities were monitored with two types of diffusive samplers, one with carbon cloth (for solvents in general) and the other with water (for methyl alcohol) as adsorbents. Solvents in the adsorbents and head-space air from urine samples were analyzed with capillary FID-GC. The measured values were subjected to linear regression analysis followed by statistical evaluation for possible sex-related differences in slopes. Essentially no significant difference was detected between men and women in regression line parameters including slopes. Possible differences in the cases of acetone and toluene were discussed and excluded. With the exceptions for acetone and toluene, the present study did not detect any clear differences between men and women. In examinations of past reports, no support for the observed differences was found. The present findings deserve further study so that a solid conclusion can be formed.

Analysis of mixtures of fatty acids and fatty alcohols in fermentation broth.

PubMed

Liu, Yilan; Chen, Ting; Yang, Maohua; Wang, Caixia; Huo, Weiyan; Yan, Daojiang; Chen, Jinjin; Zhou, Jiemin; Xing, Jianmin

2014-01-03

Microbial production of fatty acids and fatty alcohols has attracted increasing concerns because of energy crisis and environmental impact of fossil fuels. Therefore, simple and efficient methods for the extraction and quantification of these compounds become necessary. In this study, a high-performance liquid chromatography-refractive index detection (HPLC-RID) method was developed for the simultaneous quantification of fatty acids and fatty alcohols in these samples. The optimum chromatographic conditions are C18 column eluted with methanol:water:acetic acid (90:9.9:0.1, v/v/v); column temperature, 26°C; flow rate, 1.0mL/min. Calibration curves of all selected analytes showed good linearity (r(2)≥0.9989). The intra-day and inter-day relative standard deviations (RSDs) of the 10 compounds were less than 4.46% and 5.38%, respectively, which indicated that the method had good repeatability and precision. Besides, a method for simultaneous extraction of fatty acids and fatty alcohols from fermentation broth was optimized by orthogonal design. The optimal extraction conditions were as follows: solvent, ethyl acetate; solvent to sample ratio, 0.5:1; rotation speed, 2min at 260rpm; extraction temperature, 10°C. This study provides simple and fast methods to simultaneously extract and quantify fatty acids and fatty alcohols for the first time. It will be useful for the study of microbial production of these products. Copyright © 2013 Elsevier B.V. All rights reserved.

Presence and importance of organochlorine solvents and other compounds in Germany's groundwater and drinking water.

PubMed

Dieter, H H; Kerndorff, H

1993-01-01

Organochlorine compounds are widely used in Germany although the inland production of chlorinated solvents has greatly decreased since 1985. Data on groundwater contamination are incomplete, but there are some regional data sets from the States (Länder). Approximately 25% of the groundwater samples contain more than 1 microgram/l of a single solvent, the most prominent ones being tri- and tetrachloroethene, 1,1,1-trichloroethane and dichloromethane, but also chloroform. The most important causes for contaminations of the groundwater are unprotected storage and leaking sewage systems. Abandoned waste sites are, besides chlorinated compounds, also a source of many other contaminants. A ranking procedure according to their exposure potential (concentration, incidence, toxicology) is proposed. The compound of greatest concern is vinyl chloride, which is formed from tri- and tetrachloroethene under reducing conditions in the subsoil. The most important contaminant in drinking water is tetrachloroethene followed by 1,1,1-trichloroethane and trichloroethane. Chlorobenzene may also be present on occasion, while only about 20% of the finished drinking waters contain more chloroform after treatment than before. Only about 10% of all analyses of drinking water derived from groundwater shows the presence of organochlorine solvents and most of these show total concentrations less than 2 micrograms/l. The degradation product, vinyl chloride, was found up to now only in different groundwaters. To stabilize and to improve the situation, which still is much more favorable for drinking than for groundwater, precautions are going to be taken which should assure that these and other problematic substances which endanger water are used only in closed systems and rigid safety measures be imposed on their disposal and transport.

Combinatorial library based engineering of Candida antarctica lipase A for enantioselective transacylation of sec-alcohols in organic solvent.

PubMed

Wikmark, Ylva; Svedendahl Humble, Maria; Bäckvall, Jan-E

2015-03-27

A method for determining lipase enantioselectivity in the transacylation of sec-alcohols in organic solvent was developed. The method was applied to a model library of Candida antarctica lipase A (CalA) variants for improved enantioselectivity (E values) in the kinetic resolution of 1-phenylethanol in isooctane. A focused combinatorial gene library simultaneously targeting seven positions in the enzyme active site was designed. Enzyme variants were immobilized on nickel-coated 96-well microtiter plates through a histidine tag (His6-tag), screened for transacylation of 1-phenylethanol in isooctane, and analyzed by GC. The highest enantioselectivity was shown by the double mutant Y93L/L367I. This enzyme variant gave an E value of 100 (R), which is a dramatic improvement on the wild-type CalA (E=3). This variant also showed high to excellent enantioselectivity for other secondary alcohols tested. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Micron-sized columnar grains of CH3NH3PbI3 grown by solvent-vapor assisted low-temperature (75 °C) solid-state reaction: The role of non-coordinating solvent-vapor

NASA Astrophysics Data System (ADS)

Zheng, Huifeng; Liu, Yangqiao; Sun, Jing

2018-04-01

The preparation of hybrid perovskite films with large columnar grains via low-temperature solid-state reaction remains a big challenge. Conventional solvent annealing using DMF, DMSO and ethanol, etc. fails to work effectively at low temperature (<100 °C). Here, we comprehensively investigated the effects of non-coordinating solvent vapor on the properties of perovskite film, and obtained micron-sized columnar grains (with an average grain size of 1.4 μm) of CH3NH3PbI3 even at a low temperature of 75 °C when annealed with benzyl alcohol vapor. The perovskite solar cells based on benzyl-alcohol-vapor annealing (75 °C), delivered much higher photovoltaic performance, better stability and smaller hysteresis than those based on conventional thermal annealing. Additionally, a champion power conversion efficiency (PCE) of 15.1% was obtained and the average PCE reached 12.2% with a tiny deviation. Finally, the mechanism of solvent annealing with non-coordinating solvent was discussed. Moreover, we revealed that high polarity and high boiling point of the solvent used for generating vapor, was critical to grow micron-sized columnar grains at such a low temperature (75 °C). This work will contribute to understanding the mechanism of grain growth in solvent annealing and improving its facility and effectiveness.

Natural Attenuation of Chlorinated Solvents and Fuel Components (BTEX and MTBE) in Ground Water

EPA Science Inventory

Monitored Natural Attenuation is widely used in the USA to deal with ground water contamination from fuel components such as the BTEX compounds or MTBE or TBA and from chlorinated solvents such as PCE, TCE, and TCA. This presentation reviews the theory and practice of MNA in the...

Human telomere sequence DNA in water-free and high-viscosity solvents: G-quadruplex folding governed by Kramers rate theory.

PubMed

Lannan, Ford M; Mamajanov, Irena; Hud, Nicholas V

2012-09-19

Structures formed by human telomere sequence (HTS) DNA are of interest due to the implication of telomeres in the aging process and cancer. We present studies of HTS DNA folding in an anhydrous, high viscosity deep eutectic solvent (DES) comprised of choline choride and urea. In this solvent, the HTS DNA forms a G-quadruplex with the parallel-stranded ("propeller") fold, consistent with observations that reduced water activity favors the parallel fold, whereas alternative folds are favored at high water activity. Surprisingly, adoption of the parallel structure by HTS DNA in the DES, after thermal denaturation and quick cooling to room temperature, requires several months, as opposed to less than 2 min in an aqueous solution. This extended folding time in the DES is, in part, due to HTS DNA becoming kinetically trapped in a folded state that is apparently not accessed in lower viscosity solvents. A comparison of times required for the G-quadruplex to convert from its aqueous-preferred folded state to its parallel fold also reveals a dependence on solvent viscosity that is consistent with Kramers rate theory, which predicts that diffusion-controlled transitions will slow proportionally with solvent friction. These results provide an enhanced view of a G-quadruplex folding funnel and highlight the necessity to consider solvent viscosity in studies of G-quadruplex formation in vitro and in vivo. Additionally, the solvents and analyses presented here should prove valuable for understanding the folding of many other nucleic acids and potentially have applications in DNA-based nanotechnology where time-dependent structures are desired.

Can green solvents be alternatives for thermal stabilization of collagen?

PubMed

Mehta, Ami; Rao, J Raghava; Fathima, Nishter Nishad

2014-08-01

"Go Green" campaign is gaining light for various industrial applications where water consumption needs to be reduced. To resolve this, industries have adopted usage of green, organic solvents, as an alternative to water. For leather making, tanning industry consumes gallons of water. Therefore, for adopting green solvents in leather making, it is necessary to evaluate its influence on type I collagen, the major protein present in the skin matrix. The thermal stability of collagen from rat tail tendon fiber (RTT) treated with seven green solvents namely, ethanol, ethyl lactate, ethyl acetate, propylene carbonate, propylene glycol, polyethylene glycol-200 and heptane was determined using differential scanning calorimetry (DSC). Crosslinking efficiency of basic chromium sulfate and wattle on RTT in green solvents was determined. DSC thermograms show increase in thermal stability of RTT collagen against heat with green solvents (>78°C) compared to water (63°C). In the presence of crosslinkers, RTT demonstrated thermal stability >100°C in some green solvents, resulting in increased intermolecular forces between collagen, solvent and crosslinkers. The significant improvement in thermal stability of collagen potentiates the capability of green solvents as an alternative for water. Copyright © 2014 Elsevier B.V. All rights reserved.

Separation by solvent extraction

DOEpatents

Holt, Jr., Charles H.

1976-04-06

17. A process for separating fission product values from uranium and plutonium values contained in an aqueous solution, comprising adding an oxidizing agent to said solution to secure uranium and plutonium in their hexavalent state; contacting said aqueous solution with a substantially water-immiscible organic solvent while agitating and maintaining the temperature at from -1.degree. to -2.degree. C. until the major part of the water present is frozen; continuously separating a solid ice phase as it is formed; separating a remaining aqueous liquid phase containing fission product values and a solvent phase containing plutonium and uranium values from each other; melting at least the last obtained part of said ice phase and adding it to said separated liquid phase; and treating the resulting liquid with a new supply of solvent whereby it is practically depleted of uranium and plutonium.

Water quality criteria for colored smokes: Solvent Yellow 33, Final report. [Contains glossary

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

Davidson, K.A.; Hovatter, P.S.

1987-11-01

The available data on the environmental fate, aquatic toxicity, and mammalian toxicity of Solvent Yellow 33, a quinoline dye used in colored smoke grenades, were reviewed. The US Environmental Protection Agency (USEPA) guidelines were used in an attempt to generate water quality criteria for the protection of aquatic life and its use and of human health. 87 refs., 2 figs., 13 tabs.

Alcohol Oxidation at Platinum–Gas and Platinum–Liquid Interfaces: The Effect of Platinum Nanoparticle Size, Water Coadsorption, and Alcohol Concentration

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

Tatsumi, Hironori; Liu, Fudong; Han, Hui-Ling

Platinum nanoparticles size range from 1 to 8 nm deposited on mesoporous silica MCF-17 catalyzed alcohol oxidations were studied in the gas and liquid phases. Among methanol, ethanol, 2- propanol and 2-butanol reactions, the turnover frequency increased with Pt nanoparticle size for all the alcohols utilized. The activation energies for the oxidations were almost same among all alcohol species, but higher in the gas phase than those in the liquid phase. Water coadsorption poisoned the reaction in the gas phase, while it increased the reaction turnover rates in the liquid phase. Sum frequency generation (SFG) vibrational spectroscopy studies and DFTmore » calculations revealed that the alcohol molecules pack horizontally on the metal surface in low concentrations and stand up in high concentrations, which affect the dissociation of β-hydrogen of the alcohols as the critical step in alcohol oxidations.« less

Alcohol Oxidation at Platinum–Gas and Platinum–Liquid Interfaces: The Effect of Platinum Nanoparticle Size, Water Coadsorption, and Alcohol Concentration

DOE PAGES

Tatsumi, Hironori; Liu, Fudong; Han, Hui-Ling; ...

2017-03-21

Platinum nanoparticles size range from 1 to 8 nm deposited on mesoporous silica MCF-17 catalyzed alcohol oxidations were studied in the gas and liquid phases. Among methanol, ethanol, 2- propanol and 2-butanol reactions, the turnover frequency increased with Pt nanoparticle size for all the alcohols utilized. The activation energies for the oxidations were almost same among all alcohol species, but higher in the gas phase than those in the liquid phase. Water coadsorption poisoned the reaction in the gas phase, while it increased the reaction turnover rates in the liquid phase. Sum frequency generation (SFG) vibrational spectroscopy studies and DFTmore » calculations revealed that the alcohol molecules pack horizontally on the metal surface in low concentrations and stand up in high concentrations, which affect the dissociation of β-hydrogen of the alcohols as the critical step in alcohol oxidations.« less

Coniferyl alcohol reactivity at the air/water interface.

PubMed

Cathala, Bernard; Aguié-Béghin, Véronique; Douillard, Roger

2004-01-01

In order to investigate the sensitivity of the lignin monomer coupling reactions to the environment physicochemical conditions, coniferyl alcohol (CA) was polymerised at the air/water interface. Characterisation of the interface during the reaction by surface pressure measurement and ellipsometry demonstrates that the reaction occurs near or at the interface. Coupling products were analysed by HPLC and compared to reaction products obtained in the case of polymerisation in solution. Relative proportions of beta-beta and beta-O-4 dehydrodimers were found to increase in air/water interface experiment.

Solvent effects on enzymes - Implications for extraterrestrial life.

NASA Technical Reports Server (NTRS)

Heinrich, M. R.

1972-01-01

Review of several studies on the alterations taking place in the structure, catalytic activity, specificity, and stability of an enzyme when some or all of the water in the medium is replaced by another solvent. These studies show the utility of solvents as a tool for probing enzyme function. They also suggest that solvents other than water should be investigated as media for controlling and directing enzyme reactions.

Purification of a water extract of Chinese sweet tea plant (Rubus suavissimus S. Lee) by alcohol precipitation

PubMed Central

Koh, Gar Yee; Chou, Guixin; Liu, Zhijun

2009-01-01

The aqueous extraction process of the leaves of Rubus suavissimus often brings in a large amount of non-active polysaccharides as part of the constituents. To purify this water extract for potential elevated bioactivity, alcohol precipitation (AP) consisting of gradient regimens was applied, and its resultants were examined through colorimetric and HPLC analyses. AP was effective in partitioning the aqueous crude extract into a soluble supernatant and an insoluble precipitant, and its effect varied significantly with alcohol regimens. Generally, the higher the alcohol concentration, the purer was the resultant extract. At its maximum, approximately 36% (w/w) of the crude extract, of which 23% was polysaccharides, was precipitated and removed, resulting in a purified extract consisting of over 20% bioactive marker compounds (gallic acid, ellagic acid, rutin, rubusoside, and steviol monoside). The removal of 11% polysaccharides from the crude water extract by using alcohol precipitation was complete at 70% alcohol regimen. Higher alcohol levels resulted in even purer extracts, possibly by removing some compounds of uncertain bioactivity. Alcohol precipitation is an effective way of removing polysaccharides from the water extract of sweet tea plant and could be used as an initial simple purification tool for many water plant extracts that contain large amounts of polysaccharides. PMID:19419169

Flemion-based actuator with ionic liquid as solvent

NASA Astrophysics Data System (ADS)

Wang, Jin; Xu, Chunye; Taya, Minoru; Kuga, Yasuo

2006-03-01

A perfluorinated carboxylic acid membrane, i.e. Flemion, shows improved performance as actuator material compared with Nafion (perfluorinated sulfonic acide). Flemion has a higher ion exchange capacity and good mechanical strength. Especially, Flemion will deform with no back relaxation when applied electrical stimulus. However, with water as solvent, the operation of Flemion in air has serious problems. Since water would evaporate quickly in air. Moreover, the electrochemical stability for use in water is around 1V at room temperature. In previous work, investigations on Nafion with ionic liquid as solvents have been carried out and good results have been obtained. In this work, we explore the use of highly stable ionic liquid instead of water as solvent in Flemion. Experimental results indicate that Flemion based actuators with ionic liquid as solvent have improved stability as compared to the water samples. Although the forces exhibited by Flemion based actuators with the use of ionic liquid decreased dramatically as compared to water, these preliminary results suggest a good potential for use of Flemion with ionic liquid in some applications.

46. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

46. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, CONTROL PANEL LEVEL (2ND DECK) OF ETHER AND ALCOHOL STILL BUILDING, LOOKING NORTH, SHOWING TWO ALCOHOL DISTILLATION TOWERS BEHIND 'MIXED SOLVENT UNIT' CONTROL PANEL. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

Comparison of Dimethyl Sulfoxide and Water as Solvents for Echinocandin Susceptibility Testing by the EUCAST Methodology

PubMed Central

Alastruey-Izquierdo, Ana; Gómez-López, Alicia; Arendrup, Maiken C.; Lass-Florl, Cornelia; Hope, William W.; Perlin, David S.; Rodriguez-Tudela, Juan L.

2012-01-01

Ninety-six strains of Candida, including 29 resistant and 67 susceptible isolates with mutations in the FKS1 and FKS2 genes were tested by the European Committee on Antibiotic Susceptibility Testing EDef 7.1 and 7.2 methodologies to determine the impact on the MIC when water was replaced with dimethyl sulfoxide (DMSO) as the solvent for caspofungin and micafungin. The MICs were significantly lower and the MIC ranges were narrower when DMSO was used as the solvent. The use of DMSO may help to better discriminate between susceptible and resistant populations. PMID:22535988

Comparison of dimethyl sulfoxide and water as solvents for echinocandin susceptibility testing by the EUCAST methodology.

PubMed

Alastruey-Izquierdo, Ana; Gómez-López, Alicia; Arendrup, Maiken C; Lass-Florl, Cornelia; Hope, William W; Perlin, David S; Rodriguez-Tudela, Juan L; Cuenca-Estrella, Manuel

2012-07-01

Ninety-six strains of Candida, including 29 resistant and 67 susceptible isolates with mutations in the FKS1 and FKS2 genes were tested by the European Committee on Antibiotic Susceptibility Testing EDef 7.1 and 7.2 methodologies to determine the impact on the MIC when water was replaced with dimethyl sulfoxide (DMSO) as the solvent for caspofungin and micafungin. The MICs were significantly lower and the MIC ranges were narrower when DMSO was used as the solvent. The use of DMSO may help to better discriminate between susceptible and resistant populations.

Femtosecond dynamics in hydrogen-bonded solvents

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

Castner, E.W. Jr.; Chang, Y.J.

1993-09-01

We present results on the ultrafast dynamics of pure hydrogen-bonding solvents, obtained using femtosecond Fourier-transform optical-heterodyne-detected, Raman-induced Kerr effect spectroscopy. Solvent systems we have studied include the formamides, water, ethylene glycol, and acetic acid. Inertial and diffusive motions are clearly resolved. We comment on the effect that such ultrafast solvent motions have on chemical reactions in solution.

Dental adhesives and strategies for displacement of water/solvents from collagen fibrils.

PubMed

Matuda, Larissa Sgarbosa de Araújo; Marchi, Giselle Maria; Aguiar, Thaiane Rodrigues; Leme, Ariene Arcas; Ambrosano, Gláucia M B; Bedran-Russo, Ana Karina

2016-06-01

To evaluate the influence of temperature of evaporation in adhesive systems with different solvents on the apparent modulus of elasticity and mass change of macro-hybrid layers modified by proanthocyanidins (PACs). Adhesive resin beams (A) from Single Bond Plus (SB), Excite (EX) and One Step Plus (OS) were prepared after solvent evaporation at 23°C or 40°C (n=12). Macro-hybrid layers (M) (n=12) were prepared using demineralized dentin beams sectioned from extracted human third molars. The demineralized dentin specimens were infiltrated with each one of the three adhesive systems at 23°C or 40°C; with or without prior dentin treatment with PACs for 10min. The apparent modulus of elasticity (E) and mass change (Wmc, %) of adhesives beams and resin-infiltrated specimens were assessed in dry and wet conditions after immersion in water (24h, 1, 3 and 6 months). The E was statistically analyzed by Tukey-Kramer test and the Wmc, % by Kruskal Wallis, and Dunn (α=0.05). Solvent evaporation at 40°C resulted in higher E values for adhesive resin beams at all storage conditions, regardless of the adhesive system (p<0.05). Increased mass loss (3 months: -0.01%; 6 months: -0.05%) was observed in One Step resin beams (p≤0.05). In the macro-hybrid layer models the pretreatment with PACs along with solvent evaporation at 40°C increased E and decreased the Wmc, % (3 months: -2.5; 6 months: 2.75%) for adhesives evaluated over time (p<0.05). No significant differences in ratio (resin/dentin) were found for the macro-hybrid layers (p>0.05). Improved solvent evaporation at higher temperature, and increased collagen cross-linking induced by PACs, enhanced the mechanical properties resulting in highly stable macro-hybrid layers over 6 months storage. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Structural analysis of the alcohol acyltransferase protein family from Cucumis melo shows that enzyme activity depends on an essential solvent channel.

PubMed

Galaz, Sebastián; Morales-Quintana, Luis; Moya-León, María Alejandra; Herrera, Raúl

2013-03-01

Alcohol acyltransferases (AAT) play a key role in ester biosynthesis. In Cucumis melo var. cantalupensis, AATs are encoded by a gene family of four members (CmAAT1-4). CmAAT1, CmAAT3 and CmAAT4 are capable of synthesizing esters, with CmAAT1 the most active. CmAAT2 is inactive and has an Ala268 residue instead of a threonine which is present in all other active AATs, although the role of this residue is still unclear. The present work aims to understand the molecular mechanism involved in ester biosynthesis in melon fruit and to clarify the importance of the Ala268 residue. First, structural models for each protein were built by comparative modelling methodology. Afterwards, conformational interaction between the protein and several ligands, alcohols and acyl-CoAs was explored by molecular docking and molecular dynamics simulation. Structural analysis showed that CmAATs share a similar structure. Also, well-defined solvent channels were described in the CmAATs except for CmAAT2 which does not have a proper channel and instead has a small pocket around Ala268. Residues of the catalytic HxxxD motif interact with substrates within the solvent channel, with Ser363 also important. Strong binding interaction energies were described for the best substrate couple of each CmAAT (hexyl-, benzyl- and cinnamyl-acetate for CmAAT1, 3 and 4 respectively). CmAAT1 and CmAAT2 protein surfaces share similar electrostatic potentials; nevertheless the entrance channels for the substrates differ in location and electrostatic character, suggesting that Ala268 might be responsible for that. This could partly explain the major differences in activity reported for these two enzymes. © 2013 The Authors Journal compilation © 2013 FEBS.

Molecular insights into early stage aggregation of di-Fmoc-L-lysine in binary mixture of organic solvent and water

NASA Astrophysics Data System (ADS)

Huda, Md Masrul; Rai, Neeraj

Molecular gels are relatively new class of soft materials, which are formed by the supramolecular aggregation of low molecular weight gelators (LMWGs) in organic solvents and/or water. Hierarchical self-assembly of small gelator molecules lead to three-dimensional complex fibrillar networks, which restricts the flow of solvents and results in viscous solid like materials or gels. These gels have drawn significant attentions for their potential applications for drug delivery, tissue engineering, materials for sensors etc. As of now, self-assembly of gelator molecules into one-dimensional fibers is not well understood, although that is very important to design new gelators for desired applications. Here, we present molecular dynamics study that provides molecular level insight into early stage aggregation of selected gelator, di-Fmoc-L-lysine in binary mixture of organic solvent and water. We will present the role of different functional groups of gelator molecule such as aromatic ring, amide, and carboxylic group on aggregation. We will also present the effect of concentrations of gelator and solvent on self-assembly of gelators. This study has captured helical fiber growth and branching of fiber, which is in good agreement with experimental observations.

A turn-on type stimuli-responsive fluorescent dye with specific solvent effect: Implication for a new prototype of paper using water as the ink

NASA Astrophysics Data System (ADS)

Hu, Xiaochen; Liu, Yang; Duan, Yuai; Han, Jingqi; Li, Zhongfeng; Han, Tianyu

2017-09-01

In this study, we reported the photoluminescence (PL) behaviour of a new intramolecular charge transfer (ICT) compound, ((E)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzoic acid, (HABA), which shows ICT solvent effect in aprotic solvents as confirmed by absorption and emission spectra. While in protic solvents including water and ethanol, the charge transfer (CT) band significantly reduces. Remarkable fluorescence enhancement in the blue region was also observed for HABA in polar protic solvents. We described such phenomena as ;specific solvent effect;. It can be ascribed to the hydrogen bonding formation between HABA and protic solvents, which not only causes significant reduction in the rate of internal conversion but also elevates the energy gap. Density functional theory (DFT) calculations as well as the dynamics analysis were performed to further verify the existence of hydrogen bonding complexes. Stronger emission turn-on effect was observed on HABA solid film when it is treated with water and base solution. The stimuli-responsive fluorescence of HABA enables a new green printing technique that uses water/base as the ink, affording fluorescent handwritings highly distinct from the background. Thermoanalysis of the dye suggests the nice thermostability, which is highly desired for real-world printing in a wide temperature range.

Effects of solvent concentration and composition on protein dynamics: 13C MAS NMR studies of elastin in glycerol-water mixtures.

PubMed

Demuth, Dominik; Haase, Nils; Malzacher, Daniel; Vogel, Michael

2015-08-01

We use (13)C CP MAS NMR to investigate the dependence of elastin dynamics on the concentration and composition of the solvent at various temperatures. For elastin in pure glycerol, line-shape analysis shows that larger-scale fluctuations of the protein backbone require a minimum glycerol concentration of ~0.6 g/g at ambient temperature, while smaller-scale fluctuations are activated at lower solvation levels of ~0.2 g/g. Immersing elastin in various glycerol-water mixtures, we observe at room temperature that the protein mobility is higher for lower glycerol fractions in the solvent and, thus, lower solvent viscosity. When decreasing the temperature, the elastin spectra approach the line shape for the rigid protein at 245 K for all studied samples, indicating that the protein ceases to be mobile on the experimental time scale of ~10(-5) s. Our findings yield evidence for a strong coupling between elastin fluctuations and solvent dynamics and, hence, such interaction is not restricted to the case of protein-water mixtures. Spectral resolution of different carbon species reveals that the protein-solvent couplings can, however, be different for side chain and backbone units. We discuss these results against the background of the slaving model for protein dynamics. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing the Impact of Chlorinated-Solvent Sites on Metropolitan Groundwater Resources

PubMed Central

Brusseau, Mark L.; Narter, Matthew

2014-01-01

Chlorinated-solvent compounds are among the most common groundwater contaminants in the U.S.A. The majority of the many sites contaminated by chlorinated-solvent compounds are located in metropolitan areas, and most such areas have one or more chlorinated-solvent contaminated sites. Thus, contamination of groundwater by chlorinated-solvent compounds may pose a potential risk to the sustainability of potable water supplies for many metropolitan areas. The impact of chlorinated-solvent sites on metropolitan water resources was assessed for Tucson, AZ, by comparing the aggregate volume of extracted groundwater for all pump-and-treat systems associated with contaminated sites in the region to the total regional groundwater withdrawal. The analysis revealed that the aggregate volume of groundwater withdrawn for the pump-and-treat systems operating in Tucson, all of which are located at chlorinated-solvent contaminated sites, was 20% of the total groundwater withdrawal in the city for the study period. The treated groundwater was used primarily for direct delivery to local water supply systems or for reinjection as part of the pump-and-treat system. The volume of the treated groundwater used for potable water represented approximately 13% of the total potable water supply sourced from groundwater, and approximately 6% of the total potable water supply. This case study illustrates the significant impact chlorinated-solvent contaminated sites can have on groundwater resources and regional potable-water supplies. PMID:24116872

Separation of switchgrass bio-oil by water/organic solvent addition and pH adjustment

DOE PAGES

Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira; ...

2016-01-29

Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organicmore » solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a biphasic aqueous/organic dispersion was formed, and phase separation was optimized at approximately pH 6. The neutralized organic bio-oil had approximately 37% less oxygen and 100% increased heating value than the initial centrifuged bio-oil. In conclusion, the less oxygen content and increased heating value indicated a significant improvement of the bio-oil quality through neutralization.« less

Separation of switchgrass bio-oil by water/organic solvent addition and pH adjustment

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

Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira

Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organicmore » solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a biphasic aqueous/organic dispersion was formed, and phase separation was optimized at approximately pH 6. The neutralized organic bio-oil had approximately 37% less oxygen and 100% increased heating value than the initial centrifuged bio-oil. In conclusion, the less oxygen content and increased heating value indicated a significant improvement of the bio-oil quality through neutralization.« less

Interfacial micromorphological differences in hybrid layer formation between water- and solvent-based dentin bonding systems.

PubMed

Gregoire, Geneviève L; Akon, Bernadette A; Millas, Arlette

2002-06-01

Many dentin bonding systems of different compositions, and in particular containing different solvents, have been introduced to the market. Their effect on the quality of the interface requires clarification by means of comparative trials. This study investigated micromorphological differences in hybrid layer formation with a variety of commercially available water- or solvent-based dentin bonding products and their recommended compomers. Five bonding systems were used on groups of 10 teeth each as follows: group I, acetone-based system used with 36% phosphoric acid; group II, a different acetone-based system containing nano-sized particles for filler loading and used with a non-rinsing conditioner containing maleic acid; group III, the acetone-based system of group II used with 36% phosphoric acid (the only difference in the treatment for groups II and III was the acid etching system); group IV, a mixed-solvent-based system (water/ethanol) used with 37% phosphoric acid; and group V, a water-based system used with 37% phosphoric acid. Each bonding system was covered with the recommended compomer. Class I occlusal preparations were made in extracted teeth and restored with one of the above systems. Five specimens of each group were studied with optical microscopy after staining. Scanning electron microscopy was used to examine the interface of the bonding system/dentin of the other 5 teeth in each group. The optical microscopy measurements were made with a 10 x 10 reticle. A micron mark with scale was used for the scanning electron microscope. All measurements were made in microm. The following criteria were used to define a good interface: absence of voids between the different parts of the interface, uniformity of the hybrid layer, good opening of the tubuli orifices, and tag adherence to the tubuli walls. Morphological differences were found at the interface depending on dentin treatment and adhesive composition. The acetone-containing systems were associated

Thermodynamically based solvent design for enzymatic saccharide acylation with hydroxycinnamic acids in non-conventional media.

PubMed

Zeuner, Birgitte; Kontogeorgis, Georgios M; Riisager, Anders; Meyer, Anne S

2012-02-15

Enzyme-catalyzed synthesis has been widely studied with lipases (EC 3.1.1.3), but feruloyl esterases (FAEs; EC 3.1.1.73) may provide advantages such as higher substrate affinity and regioselectivity in the synthesis of hydroxycinnamate saccharide esters. These compounds are interesting because of their amphiphilicity and antioxidative potential. Synthetic reactions using mono- or disaccharides as one of the substrates may moreover direct new routes for biomass upgrading in the biorefinery. The paper reviews the available data for enzymatic hydroxycinnamate saccharide ester synthesis in organic solvent systems as well as other enzymatic hydroxycinnamate acylations in ionic liquid systems. The choice of solvent system is highly decisive for enzyme stability, selectivity, and reaction yields in these synthesis reactions. To increase the understanding of the reaction environment and to facilitate solvent screening as a crucial part of the reaction design, the review explores the use of activity coefficient models for describing these systems and - more importantly - the use of group contribution model UNIFAC and quantum chemistry based COSMO-RS for thermodynamic predictions and preliminary solvent screening. Surfactant-free microemulsions of a hydrocarbon, a polar alcohol, and water are interesting solvent systems because they accommodate different substrate and product solubilities and maintain enzyme stability. Ionic liquids may provide advantages as solvents in terms of increased substrate and product solubility, higher reactivity and selectivity, as well as tunable physicochemical properties, but their design should be carefully considered in relation to enzyme stability. The treatise shows that thermodynamic modeling tools for solvent design provide a new toolbox to design enzyme-catalyzed synthetic reactions from biomass sources. Copyright © 2011 Elsevier B.V. All rights reserved.

Docking glycosaminoglycans to proteins: analysis of solvent inclusion

NASA Astrophysics Data System (ADS)

Samsonov, Sergey A.; Teyra, Joan; Pisabarro, M. Teresa

2011-05-01

Glycosaminoglycans (GAGs) are anionic polysaccharides, which participate in key processes in the extracellular matrix by interactions with protein targets. Due to their charged nature, accurate consideration of electrostatic and water-mediated interactions is indispensable for understanding GAGs binding properties. However, solvent is often overlooked in molecular recognition studies. Here we analyze the abundance of solvent in GAG-protein interfaces and investigate the challenges of adding explicit solvent in GAG-protein docking experiments. We observe PDB GAG-protein interfaces being significantly more hydrated than protein-protein interfaces. Furthermore, by applying molecular dynamics approaches we estimate that about half of GAG-protein interactions are water-mediated. With a dataset of eleven GAG-protein complexes we analyze how solvent inclusion affects Autodock 3, eHiTs, MOE and FlexX docking. We develop an approach to de novo place explicit solvent into the binding site prior to docking, which uses the GRID program to predict positions of waters and to locate possible areas of solvent displacement upon ligand binding. To investigate how solvent placement affects docking performance, we compare these results with those obtained by taking into account information about the solvent position in the crystal structure. In general, we observe that inclusion of solvent improves the results obtained with these methods. Our data show that Autodock 3 performs best, though it experiences difficulties to quantitatively reproduce experimental data on specificity of heparin/heparan sulfate disaccharides binding to IL-8. Our work highlights the current challenges of introducing solvent in protein-GAGs recognition studies, which is crucial for exploiting the full potential of these molecules for rational engineering.

Water Quality Criteria for Colored Smokes: Solvent Yellow 33

DTIC Science & Technology

1987-11-01

Y . ’~ ~% d .’ 4’ . TABLE 4. DISTRIBUTION OF [1 4 C]-SOLVENT YELLOW 33 IN RATS 1 hr AFTER- EXPOSURE TO SOLVENT YELLOW 33 (SY) OR SOLVENT YELLOW 33...have shown that some individuals react strongly Lo this dye. The repeat insult patch test is used most often. The subjects receive five to ten exposures...70 Neutrophils Control 5 ± 2 0 ± 0 7 ± 3 3( lO cells/g) Exposed 1300 ± 130 d 470 ± i 0 0d 290 ± 50 d a. Adapted from Henderson et al. 1985b. b. Values

[Balneotherapeutics of non-alcoholic fatty liver disease with the use of the Essentuki-type drinking mineral waters].

PubMed

Fedorova, T E; Efimenko, N V; Kaĭsinova, A S

2012-01-01

The objective of the present work was to estimate the effectiveness of combined spa-and-resort treatment with the use of the Essentuki-type drinking mineral waters for the patients presenting with non-alcoholic fatty liver disease. A total of 40 patients presening with non-alcoholic fatty liver disease (NOFLD) were available for the examination. The study has demonstrated positive dynamics of clinical symptoms and results of liver functional tests, characteristics of intrahepatic dynamics, lipid metabolism, antioxidant hemostais, and the hormonal status of the patients with non-alcoholic fatty liver disease. The intake of the Essentuki-type drinking mineral waters promoted normalization of adiponectin and leptin levels in conjunction with the reduction in the degree of insulin resistance, i.e., the key pathogenetic factors responsible for hepatic steatosis and non-alcoholic steatohepatitis. It is concluded that the Essentuki-type drinking mineral waters may be recommended for the inclusion in the combined treatment and prevention of the progression of non-alcoholic fatty liver disease.

Protein-solvent preferential interactions, protein hydration, and the modulation of biochemical reactions by solvent components.

PubMed

Timasheff, Serge N

2002-07-23

Solvent additives (cosolvents, osmolytes) modulate biochemical reactions if, during the course of the reaction, there is a change in preferential interactions of solvent components with the reacting system. Preferential interactions can be expressed in terms of preferential binding of the cosolvent or its preferential exclusion (preferential hydration). The driving force is the perturbation by the protein of the chemical potential of the cosolvent. It is shown that the measured change of the amount of water in contact with protein during the course of the reaction modulated by an osmolyte is a change in preferential hydration that is strictly a measure of the cosolvent chemical potential perturbation by the protein in the ternary water-protein-cosolvent system. It is not equal to the change in water of hydration, because water of hydration is a reflection strictly of protein-water forces in a binary system. There is no direct relation between water of preferential hydration and water of hydration.

Solventless and solvent-minimized sample preparation techniques for determining currently used pesticides in water samples: a review.

PubMed

Tankiewicz, Maciej; Fenik, Jolanta; Biziuk, Marek

2011-10-30

The intensification of agriculture means that increasing amounts of toxic organic and inorganic compounds are entering the environment. The pesticides generally applied nowadays are regarded as some of the most dangerous contaminants of the environment. Their presence in the environment, especially in water, is hazardous because they cause human beings to become more susceptible to disease. For these reasons, it is essential to monitor pesticide residues in the environment with the aid of all accessible analytical methods. The analysis of samples for the presence of pesticides is problematic, because of the laborious and time-consuming operations involved in preparing samples for analysis, which themselves may be a source of additional contaminations and errors. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solventless and solvent-minimized techniques are coming into use. This paper discusses the most commonly used over the last 15 years sample preparation techniques for monitoring organophosphorus and organonitrogen pesticides residue in water samples. Furthermore, a significant trend in sample preparation, in accordance with the principles of 'Green Chemistry' is the simplification, miniaturization and automation of analytical techniques. In view of this aspect, several novel techniques are being developed in order to reduce the analysis step, increase the sample throughput and to improve the quality and the sensitivity of analytical methods. The paper describes extraction techniques requiring the use of solvents - liquid-liquid extraction (LLE) and its modifications, membrane extraction techniques, hollow fibre-protected two-phase solvent microextraction, liquid phase microextraction based on the solidification of a floating organic drop (LPME-SFO), solid-phase extraction (SPE) and single-drop microextraction (SDME) - as well as solvent

A Flemion-based actuator with ionic liquid as solvent

NASA Astrophysics Data System (ADS)

Wang, Jin; Xu, Chunye; Taya, Minoru; Kuga, Yasuo

2007-04-01

A perfluorinated carboxylic acid membrane, i.e. Flemion, shows improved performance as actuator material compared with Nafion (perfluorinated sulfonic acid). Flemion has a higher ion exchange capacity and good mechanical strength. In particular, Flemion will deform with no back relaxation under applied electrical stimulus. However, with water as solvent, the operation of Flemion in air has serious problems, since water would evaporate quickly in air. Moreover, the electrochemical stability for use in water is around 1 V at room temperature. In previous work, investigations on Nafion with ionic liquid as solvents have been carried out by some researchers and good results have been obtained. In this work, we explore the use of highly stable ionic liquid instead of water as solvent in Flemion. Experimental results indicate that Flemion-based actuators with ionic liquid as solvent have improved stability as compared to the water samples. Although the forces exhibited by Flemion-based actuators with the use of ionic liquid decreased dramatically compared to water, these preliminary results suggest good potential for the use of Flemion with ionic liquid in future applications.

Nonhazardous solvent composition and method for cleaning metal surfaces

DOEpatents

Googin, J.M.; Simandl, R.F.; Thompson, L.M.

1993-05-04

A solvent composition for displacing greasy and oily contaminants as well as water and/or aqueous residue from metallic surfaces, especially surfaces of radioactive materials so that such surfaces can be wiped clean of the displaced contaminants, water and/or aqueous residue. The solvent composition consists essentially of a blend of nonpolar aliphatic hydrocarbon solvent having a minimum flash point of about 140 F and 2 to 25 volume percent of a polar solvent having a flash point sufficiently high so as to provide the solvent composition with a minimum flash point of at least 140 F. The solvent composition is nonhazardous so that when it is used to clean the surfaces of radioactive materials the waste in the form of paper or cloth wipes, lab coats and the like used in the cleaning operation is not considered to be mixed waste composed of a hazardous solvent and a radioactive material.

Vibrational spectroscopic determination of local solvent electric field, solute-solvent electrostatic interaction energy, and their fluctuation amplitudes.

PubMed

Lee, Hochan; Lee, Gayeon; Jeon, Jonggu; Cho, Minhaeng

2012-01-12

IR probes have been extensively used to monitor local electrostatic and solvation dynamics. Particularly, their vibrational frequencies are highly sensitive to local solvent electric field around an IR probe. Here, we show that the experimentally measured vibrational frequency shifts can be inversely used to determine local electric potential distribution and solute-solvent electrostatic interaction energy. In addition, the upper limits of their fluctuation amplitudes are estimated by using the vibrational bandwidths. Applying this method to fully deuterated N-methylacetamide (NMA) in D(2)O and examining the solvatochromic effects on the amide I' and II' mode frequencies, we found that the solvent electric potential difference between O(═C) and D(-N) atoms of the peptide bond is about 5.4 V, and thus, the approximate solvent electric field produced by surrounding water molecules on the NMA is 172 MV/cm on average if the molecular geometry is taken into account. The solute-solvent electrostatic interaction energy is estimated to be -137 kJ/mol, by considering electric dipole-electric field interaction. Furthermore, their root-mean-square fluctuation amplitudes are as large as 1.6 V, 52 MV/cm, and 41 kJ/mol, respectively. We found that the water electric potential on a peptide bond is spatially nonhomogeneous and that the fluctuation in the electrostatic peptide-water interaction energy is about 10 times larger than the thermal energy at room temperature. This indicates that the peptide-solvent interactions are indeed important for the activation of chemical reactions in aqueous solution.

Lattice model for water-solute mixtures.

PubMed

Furlan, A P; Almarza, N G; Barbosa, M C

2016-10-14

A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction of solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting in, hydrophilic, inert, and hydrophobic interactions. Extensive Monte Carlo simulations were carried out, and the behavior of pure components and the excess properties of the mixtures have been studied. The pure components, water (solvent) and solute, have quite similar phase diagrams, presenting gas, low density liquid, and high density liquid phases. In the case of solute, the regions of coexistence are substantially reduced when compared with both the water and the standard ALG models. A numerical procedure has been developed in order to attain series of results at constant pressure from simulations of the lattice gas model in the grand canonical ensemble. The excess properties of the mixtures, volume and enthalpy as the function of the solute fraction, have been studied for different interaction parameters of the model. Our model is able to reproduce qualitatively well the excess volume and enthalpy for different aqueous solutions. For the hydrophilic case, we show that the model is able to reproduce the excess volume and enthalpy of mixtures of small alcohols and amines. The inert case reproduces the behavior of large alcohols such as propanol, butanol, and pentanol. For the last case (hydrophobic), the excess properties reproduce the behavior of ionic liquids in aqueous solution.

Method to produce water-soluble sugars from biomass using solvents containing lactones

DOEpatents

Dumesic, James A.; Luterbacher, Jeremy S.

2015-06-02

A process to produce an aqueous solution of carbohydrates that contains C6-sugar-containing oligomers, C6 sugar monomers, C5-sugar-containing oligomers, C5 sugar monomers, or any combination thereof is presented. The process includes the steps of reacting biomass or a biomass-derived reactant with a solvent system including a lactone and water, and an acid catalyst. The reaction yields a product mixture containing water-soluble C6-sugar-containing oligomers, C6-sugar monomers, C5-sugar-containing oligomers, C5-sugar monomers, or any combination thereof. A solute is added to the product mixture to cause partitioning of the product mixture into an aqueous layer containing the carbohydrates and a substantially immiscible organic layer containing the lactone.

Method to produce water-soluble sugars from biomass using solvents containing lactones

DOEpatents

Dumesic, James A.; Luterbacher, Jeremy S.

2017-08-08

A process to produce an aqueous solution of carbohydrates that contains C6-sugar-containing oligomers, C6 sugar monomers, C5-sugar-containing oligomers, C5 sugar monomers, or any combination thereof is presented. The process includes the steps of reacting biomass or a biomass-derived reactant with a solvent system including a lactone and water, and an acid catalyst. The reaction yields a product mixture containing water-soluble C6-sugar-containing oligomers, C6-sugar monomers, C5-sugar-containing oligomers, C5-sugar monomers, or any combination thereof. A solute is added to the product mixture to cause partitioning of the product mixture into an aqueous layer containing the carbohydrates and a substantially immiscible organic layer containing the lactone.

Efficient sample preparation method based on solvent-assisted dispersive solid-phase extraction for the trace detection of butachlor in urine and waste water samples.

PubMed

Aladaghlo, Zolfaghar; Fakhari, Alireza; Behbahani, Mohammad

2016-10-01

In this work, an efficient sample preparation method termed solvent-assisted dispersive solid-phase extraction was applied. The used sample preparation method was based on the dispersion of the sorbent (benzophenone) into the aqueous sample to maximize the interaction surface. In this approach, the dispersion of the sorbent at a very low milligram level was achieved by inserting a solution of the sorbent and disperser solvent into the aqueous sample. The cloudy solution created from the dispersion of the sorbent in the bulk aqueous sample. After pre-concentration of the butachlor, the cloudy solution was centrifuged and butachlor in the sediment phase dissolved in ethanol and determined by gas chromatography with flame ionization detection. Under the optimized conditions (solution pH = 7.0, sorbent: benzophenone, 2%, disperser solvent: ethanol, 500 μL, centrifuged at 4000 rpm for 3 min), the method detection limit for butachlor was 2, 3 and 3 μg/L for distilled water, waste water, and urine sample, respectively. Furthermore, the preconcentration factor was 198.8, 175.0, and 174.2 in distilled water, waste water, and urine sample, respectively. Solvent-assisted dispersive solid-phase extraction was successfully used for the trace monitoring of butachlor in urine and waste water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid-liquid equilibria for 2,3-butanediol + water + organic solvents at 303. 15 K

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

Sharma, S.; Pandya, G.; Chakrabarti, T.

1994-10-01

2, 3-Butanediol, an important industrial chemical, is of interest because of its application as a solvent and liquid fuel additive. Liquid-liquid equilibria at 303.15 [+-] 0.5 K were measured for water + 2, 3-butanediol + butan-1-ol, + 3-methyl-1-butanol, + 4-methyl-2-pentanone, + tributyl phosphate, and + butyl acetate. Complete phase diagrams were obtained by evaluating the solubility and tie-line results for each ternary mixture. The consistency of the tie-line results was ascertained using an Othmer-Tobias plot. The distribution coefficient and separation factors were evaluated over the immiscibility region. Among the solvents studied, butan-1-ol is the most effective one though tributyl phosphatemore » and 3-methyl-1-butanol may be preferred because of their low solubility and high selectivity.« less

Effect of solvents on the extraction of natural pigments and adsorption onto TiO2 for dye-sensitized solar cell applications

NASA Astrophysics Data System (ADS)

Al-Alwani, Mahmoud A. M.; Mohamad, Abu Bakar; Kadhum, Abd. Amir H.; Ludin, Norasikin A.

2015-03-01

Nine solvents, namely, n-hexane, ethanol, acetonitrile, chloroform, ethyl-ether, ethyl-acetate, petroleum ether, n-butyl alcohol, and methanol were used to extract natural dyes from Cordyline fruticosa, Pandannus amaryllifolius and Hylocereus polyrhizus. To improve the adsorption of dyes onto the TiO2 particles, betalain and chlorophyll dyes were mixed with methanol or ethanol and water at various ratios. The adsorption of the dyes mixed with titanium dioxide (TiO2) was also observed. The highest adsorption of the C.fruticosa dye mixed with TiO2 was achieved at ratio 3:1 of methanol: water. The highest adsorption of P.amaryllifolius dye mixed with TiO2 was observed at 2:1 of ethanol: water. H.polyrhizus dye extracted by water and mixed with TiO2 demonstrated the highest adsorption among the solvents. All extracted dye was adsorbed onto the surface of TiO2 based on Fourier Transform Infrared Spectroscopy (FTIR) analysis. The inhibition of crystallinity of TiO2 was likewise investigated by X-ray analysis. The morphological properties and composition of dyes were analyzed via SEM and EDX.

27 CFR 19.385 - Making alcohol or water solutions of denaturants.

Code of Federal Regulations, 2014 CFR

2014-04-01

... alcohol or water solutions of denaturants. If a proprietor uses a denaturant that is difficult to dissolve... working temperature, the proprietor may liquefy or dissolve the denaturant in a small amount of spirits or...

27 CFR 19.385 - Making alcohol or water solutions of denaturants.

Code of Federal Regulations, 2012 CFR

2012-04-01

... alcohol or water solutions of denaturants. If a proprietor uses a denaturant that is difficult to dissolve... working temperature, the proprietor may liquefy or dissolve the denaturant in a small amount of spirits or...

Properties of Polyvinylpyrrolidone in a Deep Eutectic Solvent

DOE PAGES

Sapir, Liel; Stanley, Christopher B.; Harries, Daniel

2016-03-10

Deep eutectic solvents (DES) are mixtures of two or more components with high melting temperatures, which form a liquid at room temperature. These DES hold great promise as green solvents for chemical processes, as they are inexpensive and environmentally friendly. Specifically, they present a unique solvating environment to polymers that is different from water. In this paper, we use small angle neutron scattering to study the polymer properties of the common, water-soluble, polyvinylpyrrolidone (PVP) in the prominent DES formed by a 1:2 molar mixture of choline chloride and urea. We find that the polymer adopts a slightly different structure inmore » DES than in water, so that at higher concentrations the polymer favors a more expanded conformation compared to the same concentration in water. Yet, the osmotic pressure of PVP solutions in DES is very similar to that in water, indicating that both solvents are of comparable quality and that the DES components interact favorably with PVP. Finally, the osmotic pressure measurements within this novel class of promising solvents should be of value toward future technological applications as well as for osmotic stress experiments in nonaqueous environments.« less

Properties of Polyvinylpyrrolidone in a Deep Eutectic Solvent

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

Sapir, Liel; Stanley, Christopher B.; Harries, Daniel

Deep eutectic solvents (DES) are mixtures of two or more components with high melting temperatures, which form a liquid at room temperature. These DES hold great promise as green solvents for chemical processes, as they are inexpensive and environmentally friendly. Specifically, they present a unique solvating environment to polymers that is different from water. In this paper, we use small angle neutron scattering to study the polymer properties of the common, water-soluble, polyvinylpyrrolidone (PVP) in the prominent DES formed by a 1:2 molar mixture of choline chloride and urea. We find that the polymer adopts a slightly different structure inmore » DES than in water, so that at higher concentrations the polymer favors a more expanded conformation compared to the same concentration in water. Yet, the osmotic pressure of PVP solutions in DES is very similar to that in water, indicating that both solvents are of comparable quality and that the DES components interact favorably with PVP. Finally, the osmotic pressure measurements within this novel class of promising solvents should be of value toward future technological applications as well as for osmotic stress experiments in nonaqueous environments.« less

Solvent extraction: the coordination chemistry behind extractive metallurgy.

PubMed

Wilson, A Matthew; Bailey, Phillip J; Tasker, Peter A; Turkington, Jennifer R; Grant, Richard A; Love, Jason B

2014-01-07

The modes of action of the commercial solvent extractants used in extractive hydrometallurgy are classified according to whether the recovery process involves the transport of metal cations, M(n+), metalate anions, MXx(n-), or metal salts, MXx into a water-immiscible solvent. Well-established principles of coordination chemistry provide an explanation for the remarkable strengths and selectivities shown by most of these extractants. Reagents which achieve high selectivity when transporting metal cations or metal salts into a water-immiscible solvent usually operate in the inner coordination sphere of the metal and provide donor atom types or dispositions which favour the formation of particularly stable neutral complexes that have high solubility in the hydrocarbons commonly used in recovery processes. In the extraction of metalates, the structures of the neutral assemblies formed in the water-immiscible phase are usually not well defined and the cationic reagents can be assumed to operate in the outer coordination spheres. The formation of secondary bonds in the outer sphere using, for example, electrostatic or H-bonding interactions are favoured by the low polarity of the water-immiscible solvents.

Aminosilicone solvent recovery methods and systems

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

Spiry, Irina Pavlovna; Perry, Robert James; Wood, Benjamin Rue

The present invention is directed to aminosilicone solvent recovery methods and systems. The methods and systems disclosed herein may be used to recover aminosilicone solvent from a carbon dioxide containing vapor stream, for example, a vapor stream that leaves an aminosilicone solvent desorber apparatus. The methods and systems of the invention utilize a first condensation process at a temperature from about 80.degree. C. to about 150.degree. C. and a second condensation process at a temperature from about 5.degree. C. to about 75.degree. C. The first condensation process yields recovered aminosilicone solvent. The second condensation process yields water.

Nonhazardous solvent composition and method for cleaning metal surfaces

DOEpatents

Googin, John M.; Simandl, Ronald F.; Thompson, Lisa M.

1993-01-01

A solvent composition for displacing greasy and oily contaminants as well as water and/or aqueous residue from metallic surfaces, especially surfaces of radioactive materials so that such surfaces can be wiped clean of the displaced contaminants, water and/or aqueous residue. The solvent composition consists essentially of a blend of nonpolar aliphatic hydrocarbon solvent having a minimum flash point of about 140.degree. F. and 2 to 25 volume percent of a polar solvent having a flash point sufficiently high so as to provide the solvent composition with a minimum flash point of at least 140.degree. F. The solvent composition is nonhazardous so that when it is used to clean the surfaces of radioactive materials the waste in the form of paper or cloth wipes, lab coats and the like used in the cleaning operation is not considered to be mixed waste composed of a hazardous solvent and a radioactive material.

SOLVENT EXTRACTION OF URANIUM VALUES

DOEpatents

Feder, H.M.; Ader, M.; Ross, L.E.

1959-02-01

A process is presented for extracting uranium salt from aqueous acidic solutions by organic solvent extraction. It consists in contacting the uranium bearing solution with a water immiscible dialkylacetamide having at least 8 carbon atoms in the molecule. Mentioned as a preferred extractant is dibutylacetamide. The organic solvent is usually used with a diluent such as kerosene or CCl/sub 4/.

Determining concentrations of 2-bromoallyl alcohol and dibromopropene in ground water using quantitative methods

USGS Publications Warehouse

Panshin, Sandra Y.

1997-01-01

A method for determining levels of 2-bromoallyl alcohol and 2,3-dibromopropene from ground-water samples using liquid/liquid extraction followed by gas chromatography/mass spectrometry is described. Analytes were extracted from the water using three aliquots of dichloromethane. The aliquots were combined and reduced in volume by rotary evaporation followed by evaporation using a nitrogen stream. The extracts were analyzed by capillary-column gas chromatography/mass spectrometry in the full-scan mode. Estimated method detection limits were 30 nanograms per liter for 2-bromoallyl alcohol and 10 nanograms per liter for 2,3-dibromopropene. Recoveries were determined by spiking three matrices at two concentration levels (0.540 and 5.40 micrograms per liter for 2-bromoallyl alcohol; and 0.534 and 5.34micro-grams per liter for dibromopropene). For seven replicates of each matrix at the high concentration level, the mean percent recoveries ranged from 43.9 to 64.9 percent for 2-bromoallyl alcohol, and from 87.5 to 99.3 percent for dibromopropene. At the low concentration level, the mean percent recoveries ranged from 43.8 to 95.2 percent for 2-bromoallyl alcohol, and from 71.3 to 84.9 percent for dibromopropene.

The solvent component of macromolecular crystals

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

Weichenberger, Christian X.; Afonine, Pavel V.; Kantardjieff, Katherine

2015-04-30

On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initialmore » phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.« less

Substitutional Growth of Methylammonium Lead Iodide Perovskites in Alcohols

DOE PAGES

Acik, Muge; Alam, Todd M.; Guo, Fangmin; ...

2017-09-29

Methylammonium lead iodide (MAPbI 3) perovskites are organic–inorganic semiconductors with long carrier diffusion lengths serving as the light-harvesting component in optoelectronics. Through a substitutional growth of MAPbI 3 catalyzed by polar protic alcohols, evidence is shown in this paper for their substrate- and annealing-free production and use of toxic solvents and high temperature is prevented. The resulting variable-sized crystals (≈100 nm–10 µm) are found to be tetragonally single-phased in alcohols and precipitated as powders that are metallic-lead-free. A comparatively low MAPbI 3 yield in toluene supports the role of alcohol polarity and the type of solvent (protic vs aprotic). Themore » theoretical calculations suggest that overall Gibbs free energy in alcohols is lowered due to their catalytic impact. Based on this alcohol-catalyzed approach, MAPbI 3 is obtained, which is chemically stable in air up to ≈1.5 months and thermally stable (≤300 °C). Finally, this method is amendable to large-scale manufacturing and ultimately can lead to energy-efficient, low-cost, and stable devices.« less

Multiple solvent crystal structures of ribonuclease A: An assessment of the method

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

Dechene, Michelle; Wink, Glenna; Smith, Mychal

2010-11-12

The multiple solvent crystal structures (MSCS) method uses organic solvents to map the surfaces of proteins. It identifies binding sites and allows for a more thorough examination of protein plasticity and hydration than could be achieved by a single structure. The crystal structures of bovine pancreatic ribonuclease A (RNAse A) soaked in the following organic solvents are presented: 50% dioxane, 50% dimethylformamide, 70% dimethylsulfoxide, 70% 1,6-hexanediol, 70% isopropanol, 50% R,S,R-bisfuran alcohol, 70% t-butanol, 50% trifluoroethanol, or 1.0M trimethylamine-N-oxide. This set of structures is compared with four sets of crystal structures of RNAse A from the protein data bank (PDB) andmore » with the solution NMR structure to assess the validity of previously untested assumptions associated with MSCS analysis. Plasticity from MSCS is the same as from PDB structures obtained in the same crystal form and deviates only at crystal contacts when compared to structures from a diverse set of crystal environments. Furthermore, there is a good correlation between plasticity as observed by MSCS and the dynamic regions seen by NMR. Conserved water binding sites are identified by MSCS to be those that are conserved in the sets of structures taken from the PDB. Comparison of the MSCS structures with inhibitor-bound crystal structures of RNAse A reveals that the organic solvent molecules identify key interactions made by inhibitor molecules, highlighting ligand binding hot-spots in the active site. The present work firmly establishes the relevance of information obtained by MSCS.« less

Glycerol triacetate as solvent and acyl donor in the production of isoamyl acetate with Candida antarctica lipase B.

PubMed

Wolfson, Adi; Atyya, Aviad; Dlugy, Christina; Tavor, Dorith

2010-03-01

Glycerol triacetate was successfully used as a green solvent and as the acyl donor in the transesterification of isoamyl alcohol to produce isoamyl acetate using free and immobilized Candida antarctica lipase B. Immobilized lipase was more catalytically active than free lipase and could be easily separated from the reaction mixture by filtration. In addition, it was found that increasing either the reaction temperature or the enzyme to substrate ratio increased the conversion of isoamyl alcohol. Using triacetin as the solvent also enabled the separation of product by simple extraction with petroleum ether and catalyst recycling.

Calixarene crown ether solvent composition and use thereof for extraction of cesium from alkaline waste solutions

DOEpatents

Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.; Presley, Derek J.

2001-01-01

A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix[4]arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.

Work ability score of solvent-exposed workers.

PubMed

Furu, Heidi; Sainio, Markku; Hyvärinen, Hanna-Kaisa; Kaukiainen, Ari

2018-03-28

Occupational chronic solvent encephalopathy (CSE), characterized by neurocognitive dysfunction, often leads to early retirement. However, only the more severe cases are diagnosed with CSE, and little is known about the work ability of solvent-exposed workers in general. The aim was to study memory and concentration symptoms, work ability and the effect of both solvent-related and non-occupational factors on work ability, in an actively working solvent-exposed population. A questionnaire on exposure and health was sent to 3640 workers in four solvent-exposed fields, i.e. painters and floor-layers, boat builders, printers, and metal workers. The total number of responses was 1730. We determined the work ability score (WAS), a single question item of the Work Ability Index, and studied solvent exposure, demographic factors, Euroquest memory and concentration symptoms, chronic diseases, and employment status using univariate and multivariate analyses. The findings were compared to those of a corresponding national blue-collar reference population (n = 221), and a small cohort of workers with CSE (n = 18). The proportion of workers with memory and concentration symptoms was significantly associated with solvent exposure. The WAS of solvent-exposed workers was lower than that of the national blue-collar reference group, and the difference was significant in the oldest age group (those aged over 60). Solvent-exposed worker's WAS were higher than those of workers diagnosed with CSE. The WAS were lowest among painters and floor-layers, followed by metal workers and printers, and highest among boat builders. The strongest explanatory factors for poor work ability were the number of chronic diseases, age and employment status. Solvent exposure was a weak independent risk factor for reduced WAS, comparable to a level of high alcohol consumption. Even if memory and concentration symptoms were associated with higher solvent exposure, the effect of solvents on self

Deep eutectic solvents as efficient solvent system for the extraction of κ-carrageenan from Kappaphycus alvarezii.

PubMed

Das, Arun Kumar; Sharma, Mukesh; Mondal, Dibyendu; Prasad, Kamalesh

2016-01-20

Three different deep eutectic solvents (DESs) prepared by the complexation of choline chloride with urea, ethylene glycol and glycerol along with their hydrated counterparts were used for the selective extraction of κ-carrageenan from Kappaphycus alvarezii. Upon comparison of the quality of the polysaccharide with the one obtained using water as extraction media as well as the one extracted using widely practiced conventional method, it was found that, the physicochemical as well as rheological properties of κ-carrageenan obtained using DESs as solvents was at par to the one obtained using conventional method and was superior in quality when compared to κ-carrageenan obtained using water as solvent. Considering the tedious nature of the extraction method employed in conventional extraction process, the DESs can be considered as suitable alternative solvents for the facile extraction of the polysaccharide directly from the seaweed. However, among the hydrated and non-hydrated DESs, the hydrated ones were found to be more effective in comparison to their non-hydrated counterparts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation of highly pure zeaxanthin particles from sea water-cultivated microalgae using supercritical anti-solvent recrystallization.

PubMed

Chen, Chao-Rui; Hong, Siang-En; Wang, Yuan-Chuen; Hsu, Shih-Lan; Hsiang, Daina; Chang, Chieh-Ming J

2012-01-01

Xanthophylls, including zeaxanthin, are considered dietary supplements with a potentially positive impact on age-related macular degeneration. Using pilot-scale column fractionation coupled with supercritical anti-solvent (SAS) recrystallization, highly pure zeaxanthin particulates were prepared from ultrasonic extracts of the microalgae, Nannochloropsis oculata, grown in sea water. Column partition chromatography increased the concentration of zeaxanthin from 36.2 mg/g of the ultrasonic extracts to 425.6 mg/g of the collected column fractions. A response surface methodology was systematically designed for the SAS process by changing feed concentration, CO(2) flow rate and anti-solvent pressure. Zeaxanthin-rich particles with a purity of 84.2% and a recovery of 85.3% were produced using supercritical anti-solvent recrystallization from the column eluate at a feed concentration of 1.5 mg/mL, CO(2) flow rate of 48.6 g/min and pressure of 135 bar. Copyright © 2011 Elsevier Ltd. All rights reserved.

Process to prepare stable trifluorostyrene containing compounds grafted to base polymers using a solvent/water mixture

DOEpatents

Roelofs, Mark Gerrit; Yang, Zhen-Yu; Han, Amy Qi

2010-06-15

A fluorinated ion exchange polymer is prepared by grafting at least one grafting monomer derived from trifluorostyrene on to at least one base polymer in a organic solvent/water mixture. These ion exchange polymers are useful in preparing catalyst coated membranes and membrane electrode assemblies used in fuel cells.

Cooperative effects in the structuring of fluoride water clusters: Ab initio hybrid quantum mechanical/molecular mechanical model incorporating polarizable fluctuating charge solvent

NASA Astrophysics Data System (ADS)

Bryce, Richard A.; Vincent, Mark A.; Malcolm, Nathaniel O. J.; Hillier, Ian H.; Burton, Neil A.

1998-08-01

A new hybrid quantum mechanical/molecular mechanical model of solvation is developed and used to describe the structure and dynamics of small fluoride/water clusters, using an ab initio wave function to model the ion and a fluctuating charge potential to model the waters. Appropriate parameters for the water-water and fluoride-water interactions are derived, with the fluoride anion being described by density functional theory and a large Gaussian basis. The role of solvent polarization in determining the structure and energetics of F(H2O)4- clusters is investigated, predicting a slightly greater stability of the interior compared to the surface structure, in agreement with ab initio studies. An extended Lagrangian treatment of the polarizable water, in which the water atomic charges fluctuate dynamically, is used to study the dynamics of F(H2O)4- cluster. A simulation using a fixed solvent charge distribution indicates principally interior, solvated states for the cluster. However, a preponderance of trisolvated configurations is observed using the polarizable model at 300 K, which involves only three direct fluoride-water hydrogen bonds. Ab initio calculations confirm this trisolvated species as a thermally accessible state at room temperature, in addition to the tetrasolvated interior and surface structures. Extension of this polarizable water model to fluoride clusters with five and six waters gave less satisfactory agreement with experimental energies and with ab initio geometries. However, our results do suggest that a quantitative model of solvent polarization is fundamental for an accurate understanding of the properties of anionic water clusters.

Effect of Different Solvents on the Measurement of Phenolics and the Antioxidant Activity of Mulberry (Morus atropurpurea Roxb.) with Accelerated Solvent Extraction.

PubMed

Yang, Jiufang; Ou, XiaoQun; Zhang, Xiaoxu; Zhou, ZiYing; Ma, LiYan

2017-03-01

The effects of 9 different solvents on the measurement of the total phenolics and antioxidant activities of mulberry fruits were studied using accelerated solvent extraction (ASE). Sixteen to 22 types of phenolics (flavonols, flavan-3-ols, flavanol, hydroxycinnamic acids, hydroxybenzoic acids, and stilbenes) from different mulberry extracts were characterized and quantified using HPLC-MS/MS. The principal component analysis (PCA) was used to determine the suitable solvents to distinguish between different classes of phenolics. Additionally, the phenolic extraction abilities of ASE and ultrasound-assisted extraction (UAE) were compared. The highest extraction efficiency could be achieved by using 50% acidified methanol (50MA) as ASE solvents with 15.14 mg/gallic acid equivalents g dry weight of mulberry fruit. The PCA results revealed that the 50MA followed by 50% acidified acetone (50AA) was the most efficient solvent for the extraction of phenolics, particularly flavonols (627.12 and 510.31 μg/g dry weight, respectively), while water (W) was not beneficial to the extraction of all categories of phenolics. Besides, the results of 3 antioxidant capability assays (DPPH, ABTS free radical-scavenging assay, and ferric-reducing antioxidant power assay) showed that water-based organic solvents increased the antioxidant capabilities of the extracts compared with water or pure organic solvents. ASE was more suitable for the extraction of phenolics than UAE. © 2017 Institute of Food Technologists®.

Evaluation of the influence of the internal aqueous solvent structure on electrostatic interactions at the protein-solvent interface by nonlocal continuum electrostatic approach.

PubMed

Rubinstein, Alexander; Sherman, Simon

The dielectric properties of the polar solvent on the protein-solvent interface at small intercharge distances are still poorly explored. To deconvolute this problem and to evaluate the pair-wise electrostatic interaction (PEI) energies of the point charges located at the protein-solvent interface we used a nonlocal (NL) electrostatic approach along with a static NL dielectric response function of water. The influence of the aqueous solvent microstructure (determined by a strong nonelectrostatic correlation effect between water dipoles within the orientational Debye polarization mode) on electrostatic interactions at the interface was studied in our work. It was shown that the PEI energies can be significantly higher than the energies evaluated by the classical (local) consideration, treating water molecules as belonging to the bulk solvent with a high dielectric constant. Our analysis points to the existence of a rather extended, effective low-dielectric interfacial water shell on the protein surface. The main dielectric properties of this shell (effective thickness together with distance- and orientation-dependent dielectric permittivity function) were evaluated. The dramatic role of this shell was demonstrated when estimating the protein association rate constants.

Solvent production by engineered Ralstonia eutropha: channeling carbon to biofuel.

PubMed

Chakravarty, Jayashree; Brigham, Christopher J

2018-06-01

Microbial production of solvents like acetone and butanol was a couple of the first industrial fermentation processes to gain global importance. These solvents are important feedstocks for the chemical and biofuel industry. Ralstonia eutropha is a facultatively chemolithoautotrophic bacterium able to grow with organic substrates or H 2 and CO 2 under aerobic conditions. This bacterium is a natural producer of polyhydroxyalkanoate biopolymers. Recently, with the advances in the development of genetic engineering tools, the range of metabolites R. eutropha can produce has enlarged. Its ability to utilize various carbon sources renders it an interesting candidate host for synthesis of renewable biofuel and solvent production. This review focuses on progress in metabolic engineering of R. eutropha for the production of alcohols, terpenes, methyl ketones, and alka(e)nes using various resources. Biological synthesis of solvents still presents the challenge of high production costs and competition from chemical synthesis. Better understanding of R. eutropha biology will support efforts to engineer and develop superior microbial strains for solvent production. Continued research on multiple fronts is required to engineer R. eutropha for truly sustainable and economical solvent production.

The Future of Polar Organometallic Chemistry Written in Bio-Based Solvents and Water.

PubMed

García-Álvarez, Joaquín; Hevia, Eva; Capriati, Vito

2018-06-19

There is a strong imperative to reduce the release of volatile organic compounds (VOCs) into the environment, and many efforts are currently being made to replace conventional hazardous VOCs in favour of safe, green and bio-renewable reaction media that are not based on crude petroleum. Recent ground-breaking studies from a few laboratories worldwide have shown that both Grignard and (functionalised) organolithium reagents, traditionally handled under strict exclusion of air and humidity and in anhydrous VOCs, can smoothly promote both nucleophilic additions to unsaturated substrates and nucleophilic substitutions in water and other bio-based solvents (glycerol, deep eutectic solvents), competitively with protonolysis, at room temperature and under air. The chemistry of polar organometallics in the above protic media is a complex phenomenon influenced by several factors, and understanding its foundational character is surely stimulating in the perspective of the development of a sustainable organometallic chemistry. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ALKYL PYROPHOSPHATE METAL SOLVENT EXTRACTANTS AND PROCESS

DOEpatents

Long, R.L.

1958-09-30

A process is presented for the recovery of uranium from aqueous mineral acidic solutions by solvent extraction. The extractant is a synmmetrical dialkyl pyrophosphate in which the alkyl substituents have a chain length of from 4 to 17 carbon atoms. Mentioned as a preferred extractant is dioctyl pyrophosphate. The uranium is precipitated irom the organic extractant phase with an agent such as HF, fluoride salts. alcohol, or ammonia.

Solvent-induced dimensional changes in EDTA-demineralized dentin matrix.

PubMed

Pashley, D H; Agee, K A; Nakajima, M; Tay, F R; Carvalho, R M; Terada, R S; Harmon, F J; Lee, W K; Rueggeberg, F A

2001-08-01

The purpose of this study was to test the null hypothesis that the re-expansion of dried matrix and the shrinkage of moist, demineralized dentin is not influenced by polar solvents. Dentin disks were prepared from midcoronal dentin of extracted human third molars. After complete demineralization in 0.5M of EDTA (pH 7), the specimens were placed in the well of a device that measures changes in matrix height in real time. Dry, collapsed matrices were created by blowing dry N(2) on the specimens until they shrank to a stable plateau. Polar solvents [water, methanol, ethanol, n-propanol, n-butanol, formamide, ethylene glycol, hydroxyethyl methacrylate (HEMA), or mixtures of water-HEMA] as model primers then were added and the degree of re-expansion measured. These same solvents also were applied to moist, expanded matrices and the solvent-induced shrinkages measured. Regression analysis was used to test the correlations between matrix height and Hansen's dispersive, polar, hydrogen bonding, and total solubility parameters (delta(d), delta(p), delta(h), delta(t)). The results indicate that water-free polar solvents of low hydrogen bonding (H-bond) ability (e.g., neat HEMA) do not re-expand dried matrices and that they shrink moist matrices. When HEMA was mixed with progressively higher water concentrations, the model water-HEMA primers expanded the dried matrix in proportion to their water concentrations and they produced less shrinkage of moist matrices. Solvents with higher H-bonding capacities (methanol, ethanol, ethylene glycol, formamide, and water) re-expanded the dried matrix in proportion to their solubility parameters for H-bonding (delta(h)). They also induced small transient shrinkages of moist matrices, which slowly re-expanded. The results require rejection of the null hypothesis. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 56: 273-281, 2001

Spin-crossover in [Fe(3-bpp)2][BF4]2 in different solvents--a dramatic stabilisation of the low-spin state in water.

PubMed

Barrett, Simon A; Kilner, Colin A; Halcrow, Malcolm A

2011-12-07

The temperature of spin-crossover in [Fe(3-bpp)(2)][BF(4)](2) (3-bpp = 2,6-di{pyrazol-3-yl}pyridine) tends to increase in associating solvents. In particular, T(½) shifts to 60-70 K higher temperature in water compared to organic solvents.

Superhydrophobic silica wool—a facile route to separating oil and hydrophobic solvents from water

NASA Astrophysics Data System (ADS)

Crick, Colin R.; Bhachu, Davinder S.; Parkin, Ivan P.

2014-12-01

Silica microfiber wool was systematically functionalized in order to provide an extremely water repellent and oleophilic material. This was carried out using a two-step functionalization that was shown to be a highly effective method for generating an intense water repulsion and attraction for oil. A demonstration of the silica wools application is shown through the highly efficient separation of oils and hydrophobic solvents from water. Water is confined to the extremities of the material, while oil is absorbed into the voids within the wool. The effect of surface functionalization is monitored though observing the interaction of the material with both oils and water, in addition to scanning electron microscope images, x-ray photoelectron spectroscopy and energy dispersive x-ray analysis. The material can be readily utilized in many applications, including the cleaning of oil spills and filtering during industrial processes, as well as further water purification tasks—while not suffering the losses of efficiency observed in current leading polymeric materials.

CHLORINATED SOLVENT PLUME CONTROL

EPA Science Inventory

This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE).

Occupational exposure to petroleum-based and oxygenated solvents and hypopharyngeal and laryngeal cancer in France: the ICARE study.

PubMed

Barul, Christine; Carton, Matthieu; Radoï, Loredana; Menvielle, Gwenn; Pilorget, Corinne; Bara, Simona; Stücker, Isabelle; Luce, Danièle

2018-04-05

To examine associations between occupational exposure to petroleum-based and oxygenated solvents and the risk of hypopharyngeal and laryngeal cancer. ICARE is a large, frequency-matched population-based case-control study conducted in France. Lifetime occupational history, tobacco smoking and alcohol consumption were collected. Analyses were restricted to men and included 383 cases of hypopharyngeal cancer, 454 cases of laryngeal cancer, and 2780 controls. Job-exposure matrices were used to assess exposure to five petroleum-based solvents (benzene; gasoline; white spirits; diesel, fuels and kerosene; special petroleum products) and to five oxygenated solvents (alcohols; ketones and esters; ethylene glycol; diethyl ether; tetrahydrofuran). Odds ratios (ORs) adjusted for smoking, alcohol drinking and other potential confounders and 95% confidence intervals (CI) were estimated with unconditional logistic models. No significant association was found between hypopharyngeal or laryngeal cancer risk and exposure to the solvents under study. Non-significantly elevated risks of hypopharyngeal cancer were found in men exposed to high cumulative levels of white spirits (OR = 1.46; 95% CI: 0.88-2.43) and tetrahydrofuran (OR = 2.63; 95CI%: 0.55-12.65), with some indication of a dose-response relationship (p for trend: 0.09 and 0.07 respectively). This study provides weak evidence for an association between hypopharyngeal cancer and exposure to white spirits and tetrahydrofuran, and overall does not suggest a substantial role of exposure to petroleum-based or oxygenated solvents in hypopharyngeal or laryngeal cancer risk.

Long-life of a bubble on the surface of a water-alcohol mixture

NASA Astrophysics Data System (ADS)

Rage, Gibran; Hernandez-Sanchez, J. Federico; Wilhelmus, Monica M.; Zenit, Roberto

2016-11-01

The lifetime of superficial bubbles has been used traditionally to determine the alcohol content in destilled beverages and spirits. With the proper alcohol content, the bubbles, known as pearls, have a particularly long life which is much longer than that in either pure water or pure ethanol. To understand this peculiar behavior, we conducted controlled experiments in water-ethanol mixtures and in samples of mezcal, an artisanal agave spirit. We assess the effect of the changes in viscosity, surface tension and density of the liquids. Also, we analyzed the effects of surfactants and evaporation rate differences, which lead to Marangoni convection in the draining film.

Controlling Actinide Hydration in Mixed Solvent Systems: Towards Tunable Solvent Systems to Close the Fuel Cycle

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

Clark, Sue B.

2016-10-31

The goal of this project has been to define the extent of hydration the f-elements and other cations in mixed solvent electrolyte systems. Methanol-water and other mixed solvent systems have been studied, where the solvent dielectric constant was varied systematically. Thermodynamic and spectroscopic studies provide details concerning the energetics of complexation and other reactions of these cations. This information has also been used to advance new understanding of the behavior of these cations in a variety of systems, ranging from environmental studies, chromatographic approaches, and ionization processes for mass spectrometry.

Solvent removal during synthetic and Nephila fiber spinning.

PubMed

Kojic, Nikola; Kojic, Milos; Gudlavalleti, Sauri; McKinley, Gareth

2004-01-01

The process by which spiders make their mechanically superior fiber involves removal of solvent (water) from a concentrated protein solution while the solution flows through a progressively narrowing spinning canal. Our aim was to determine a possible mechanism of spider water removal by using a computational model. To develop appropriate computational techniques for modeling of solvent removal during fiber spinning, a study was first performed using a synthetic solution. In particular, the effect of solvent removal during elongational flow (also exhibited in the spinning canal of the spider) on fiber mechanical properties was examined. The study establishes a model for solvent removal during dry spinning of synthetic fibers, assuming that internal diffusion governs solvent removal and that convective resistance is small. A variable internal solvent diffusion coefficient, dependent on solvent concentration, is also taken into account in the model. An experimental setup for dry (air) spinning was used to make fibers whose diameter was on the order of those made by spiders (approximately 1 microm). Two fibers of different thickness, corresponding to different spinning conditions, were numerically modeled for solvent removal and then mechanically tested. These tests showed that the thinner fiber, which lost more solvent under elongational flow, had 5-fold better mechanical properties (elastic modulus of 100 MPa and toughness of 15 MJ/m3) than the thicker fiber. Even though the mechanical properties were far from those of dragline spider silk (modulus of 10 GPa and toughness of 150 MJ/m3), the experimental methodology and numerical principles developed for the synthetic case proved to be valuable when establishing a model for the Nephila spinning process. In this model, an assumption of rapid convective water removal at the spinning canal wall was made, with internal diffusion of water through the fiber as the governing process. Then the diffusion coefficient of water

TES buffer-induced phase separation of aqueous solutions of several water-miscible organic solvents at 298.15 K: phase diagrams and molecular dynamic simulations.

PubMed

Taha, Mohamed; Lee, Ming-Jer

2013-06-28

Water and the organic solvents tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone are completely miscible in all proportions at room temperature. Here, we present new buffering-out phase separation systems that the above mentioned organic aqueous solutions can be induced to form two liquid phases in the presence of a biological buffer 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES). The lower liquid phase is rich in water and buffer, and the upper phase is organic rich. This observation has both practical and mechanistic interests. The phase diagrams of these systems were constructed by experimental measurements at ambient conditions. Molecular dynamic (MD) simulations were performed for TES + water + THF system to understand the interactions between TES, water, and organic solvent at molecular level. Several composition-sets for this system, beyond and inside the liquid-liquid phase-splitting region, have been simulated. Interestingly, the MD simulation for compositions inside the phase separation region showed that THF molecules are forced out from the water network to start forming a new liquid phase. The hydrogen-bonds, hydrogen-bonds lifetimes, hydrogen-bond energies, radial distribution functions, coordination numbers, the electrostatic interactions, and the van der Waals interactions between the different pairs have been calculated. Additionally, MD simulations for TES + water + tert-butanol∕acetonitrile∕acetone phase separation systems were simulated. The results from MD simulations provide an explanation for the buffering-out phenomena observed in [TES + water + organic solvent] systems by a mechanism controlled by the competitive interactions of the buffer and the organic solvent with water. The molecular mechanism reported here is helpful for designing new benign separation materials.

Inert Reassessment Document for n-Decyl Alcohol

EPA Pesticide Factsheets

Industrially, both alcohols are used as ingredients in perfumes, flavoring agents, and industrial solvents. In addition, the U s. S Food and Drug Administration (FDA) has approved the use of both chemicals as direct food additives.

Stability of coordination compounds of Ni2+ and Co2+ ions with succinic acid anion in water-ethanol solvents

NASA Astrophysics Data System (ADS)

Tukumova, N. V.; Dieu Thuan, Tran Thi; Usacheva, T. R.; Koryshev, N. E.; Sharnin, V. A.

2017-04-01

Stability constants of the coordination compounds of nickel(II) and cobalt(II) ions with succinic acid anion in water-ethanol solvents are determined via potentiometric titration at ionic strength of 0.1 and at T = 298.15 K. It is found that logβ values of monoligand complexes of these ions and succinic acid anions rise along with the content of ethanol in solution ( X EtOH = 0-0.7 mole fractions). Based on an analysis of the thermodynamic characteristics of the solvation of the reagents involved in complex formation, it is found that the increased stability of succinate complexes of nickel(II) and cobalt(II) ions in water-ethanol solvents is mainly determined by the weakening of the solvation of succinic acid anion (Y2-).

Revealing the physicochemical mechanism for ultrasonic separation of alcohol-water mixtures

NASA Astrophysics Data System (ADS)

Kirpalani, D. M.; Toll, F.

2002-08-01

The selective separation of ethanol from ethanol-water mixtures by ultrasonic atomization has been reported recently by Sato, Matsuura, and Fujii [J. Chem. Phys. 114, 2382 (2001)]. In that work, experimental data were reported that confirmed the generation of an ethanol-rich droplet mist and attempted to explain the selective separation in terms of parametric decay instability of the capillary wave formed during sonication. In the present work, an alternate mechanism based on the conjunction theory has been postulated for the process of ultrasonic atomization. This mechanism involves the formation of cavitating bubbles in the liquid during sonication and their eventual collapse at the liquid surface into a cloud of microbubbles that moves upwards in a capillary fountain jet. The selective separation of alcohols has been explained as a corollary effect of the physical mechanism resulting in a surface excess of alcohol molecules formed at the surface of the microbubbles. The alcohol molecules vaporize into the microbubbles and release an alcohol-rich mist on their collapse in regions of high accumulation of acoustic energy.

Biofiltration of solvent vapors from air

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

Oh, Young-sook.

1993-01-01

For various industrial solvent vapors, biofiltration promises to offer a cost-effective emission control technology. Exploiting the full potential of this technology will help attain the goals of the Clean Air Act Amendments of 1990. Concentrating on large volumes of volatile industrial solvents, stable multicomponent microbial enrichments capable of growing a mineral medium with solvent vapors as their only source of carbon and energy were obtained from soil and sewage sludge. These consortia were immobilized on an optimized porous solid support (ground peat moss and perlite). The biofilter material was packed in glass columns connected to an array of pumps andmore » flow meters that allowed the independent variation of superficial velocity and solvent vapor concentrations. In various experiments, single solvents, such as methanol, butanol, acetonitrile, hexane and nitrobenzene, and solvent mixtures, such as benzene-toluene-xylene (BTX) and chlorobenzene-o-dichlorobenzene (CB/DCB) were biofiltered with rates ranging from 15 to334 g solvent removed per m[sup 3] filter volume /h. Pressure drops were low to moderate (0-10 mmHg/m) and with periodic replacement of moisture, the biofiltration activity could be maintained for a period of several months. The experimental data on methanol biofiltration were subjected to mathematical analysis and modeling by the group of Dr. Baltzis at NJIT for a better understanding and a possible scale up of solvent vapor biofilters. In the case of chlorobenzenes and nitrobenzene, the biofilter columns had to be operated with water recirculation in a trickling filter mode. To prevent inactivation of the trickling filter by acidity during CB/DCB removal, pH control was necessary, and the removal rate of CB/DCB was strongly influenced by the flow rate of the recyling water. Nitrobenzene removal in a trickling filter did not require pH control, since the nitro group was reduced and volatilized as ammonia.« less

Degradation of palm oil empty fruit bunch (EFB) into bio-oil in sub-and supercritical solvents

NASA Astrophysics Data System (ADS)

Sarwono, Rakhman; Pusfitasari, Eka Dian

2017-01-01

Hydrothemal Liquefaction (HTL) of empty fruit bunch (EFB) of palm oil in different solvents (water, ethanol and hexane) were comparatively investigated. Experiments were carried out in an autoclave in different EFB loading of 9%, 11%, and 13%. The temperature operation was 350 oC, without any catalysts and reaction time of 5 hours. The efficiency of above solvents in terms of conversion rate, soluble liquid and carbon products were found in this experiments. The water solvent gave higher conversion rate of 35 - 36.5 %, while hexane gave conversion of 17 - 25.25 %, and ethanol gave the lower conversion rate of 12.65 - 30.3%, respectively. Increasing the EFB load decreased the conversion rate for ethanol and hexane solvents, for water there are no significant change in the conversion rate. The bio-oil as soluble liquid produced were in order of water, ethanol, and hexane solvents, respectively. The chemical properties of bio-oil products were significantly affected by the type of liquefaction solvent. The compositional of bio-oil consists of mostly of a mixture of organic acids, ketones, and esters. The hexane and ethanol solvents resulted mostly organic acids. In water solvent resulted 2-pentanone, 4-hydroxy-4-methyl and others substances. According to the bio-oil results, organic solvents resulted higher HHV compared to water solvent. The higher heating value (HHV) of the carbon products were also comparatively, ethanol solvent resulted soluble liquid with higher HHV compared to the water solvent.

Ultrathin Hydrophobic Coatings Obtained on Polyethylene Terephthalate Materials in Supercritical Carbon Dioxide with Co-Solvents

NASA Astrophysics Data System (ADS)

Kumeeva, T. Yu.; Prorokova, N. P.

2018-02-01

The surface properties of ultradisperse polytetrafluoroethylene coatings on polyethylene terephthalate materials modified in a supercritical carbon dioxide medium with co-solvent additions (aliphatic alcohols) were analyzed. An atomic force microscopy study revealed the peculiarities of the morphology of the hydrophobic coatings formed in the presence of co-solvents. The contribution of the co-solvents to the formation of the surface layer with a low surface energy was evaluated from the surface energy components of the modified polyester material. The stability of the coatings against dry friction was analyzed.

COMPARISON OF SORPTION ENERGTICS FOR HYDROPHOBIC ORGANIC CHEMICALS BY SYNTHETIC AND NATURAL SORBENTS FROM METHANOL/WATER SOLVENT MIXTURES

EPA Science Inventory

Reversed-phase liquid chromatography (RPLC) was used to investigate the thermodynamics and mechanisms of hydrophobic organic chemical (HOC) retention from methanol/water solvent mixtures. The enthalpy-entropy compensation model was used to infer that the hydro- phobic sorptive me...

Desolventizing of Jatropha curcas oil from azeotropes of solvents using ceramic membranes.

PubMed

Carniel, Naira; Zabot, Giovani L; Paliga, Marshall; Mignoni, Marcelo L; Mazutti, Marcio A; Priamo, Wagner L; Oliveira, J V; Di Luccio, Marco; Tres, Marcus V

2017-12-01

The separation of Jatropha curcas oil from azeotropes of ethyl alcohol-n-hexane and isopropyl alcohol-n-hexane using ceramic membranes with different cutoffs (5, 10 and 20 kDa) is presented. The mass ratios of oil:azeotropes (O:S) studied were 1:3 for feeding pressures of 0.1, 0.2 and 0.3 MPa, and 1:1 for the feeding pressure of 0.1 MPa. Isopropyl alcohol was the best solvent for the membranes conditioning to permeate n-hexane (240 kg/m 2  h). In the separation of J. curcas oil and azeotropes of solvents, both membranes showed oil retention and total flux decreases with time. Overall, the lowest decrease in the retentions was reached in the 5 kDa membrane, while the lowest decrease in the total flux was reached in the 20 kDa. In the separation of oil and ethyl alcohol-n-hexane azeotrope, the best retention at 60 min of the process was equal to 17.3 wt% in the 20 kDa membrane at 0.3 MPa and O:S ratio equalled to 1:3. In this condition, the total permeate flux was 17.5 kg/m 2  h. Different retentions and permeabilities are provided when changing the O:S ratio, the feeding pressure and the molecular weight cutoff of membranes.

Energy requirements of the switchable polarity solvent forward osmosis (SPS-FO) water purification process

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

Wendt, Daniel S.; Orme, Christopher J.; Mines, Gregory L.

A model was developed to estimate the process energy requirements of a switchable polarity solvent forward osmosis (SPS FO) system for water purification from aqueous NaCl feed solution concentrations ranging from 0.5 to 4.0 molal at an operational scale of 480 m3/day (feed stream). The model indicates recovering approximately 90% of the water from a feed solution with NaCl concentration similar to seawater using SPS FO would have total equivalent energy requirements between 2.4 and 4.3 kWh per m 3 of purified water product. The process is predicted to be competitive with current costs for disposal/treatment of produced water frommore » oil and gas drilling operations. As a result, once scaled up the SPS FO process may be a thermally driven desalination process that can compete with the cost of seawater reverse osmosis.« less

Energy requirements of the switchable polarity solvent forward osmosis (SPS-FO) water purification process

DOE PAGES

Wendt, Daniel S.; Orme, Christopher J.; Mines, Gregory L.; ...

2015-08-01

A model was developed to estimate the process energy requirements of a switchable polarity solvent forward osmosis (SPS FO) system for water purification from aqueous NaCl feed solution concentrations ranging from 0.5 to 4.0 molal at an operational scale of 480 m3/day (feed stream). The model indicates recovering approximately 90% of the water from a feed solution with NaCl concentration similar to seawater using SPS FO would have total equivalent energy requirements between 2.4 and 4.3 kWh per m 3 of purified water product. The process is predicted to be competitive with current costs for disposal/treatment of produced water frommore » oil and gas drilling operations. As a result, once scaled up the SPS FO process may be a thermally driven desalination process that can compete with the cost of seawater reverse osmosis.« less

Gas chromatography/isotope ratio mass spectrometry: analysis of methanol, ethanol and acetic acid by direct injection of aqueous alcoholic and acetic acid samples.

PubMed

Ai, Guomin; Sun, Tong; Dong, Xiuzhu

2014-08-15

Methanol, ethanol, and acetic acid are not easily extracted from aqueous samples and are susceptible to isotope fractionation in gas chromatography/isotope ratio mass spectrometry (GC/IRMS) analysis. Developing a direct dilution GC/IRMS method for aqueous samples, by adjusting the sample concentrations in common solvents to be similar to each other and using a fixed GC split ratio, is very convenient and important because any linearity effects caused by amount-dependent isotope fractionation can be avoided. The suitability of acetonitrile and acetone solvents for the GC/IRMS analysis of pure methanol, ethanol and acetic acid, and commercial liquor and vinegar samples was evaluated using n-hexane and water as control solvents. All the solvents including water were separated from the analyte on a HP-INNOWAX column and were diverted away from the combustion interface. The influence of liquor matrix on the ethanol GC/IRMS analyses was evaluated by adding pure ethanol to liquor samples. Acetonitrile and acetone gave similar δ(13) C values for pure ethanol and pure acetic acid to those obtained in water and n-hexane, and also gave similar δ(13) C values of ethanol in liquor and acetic acid in white vinegar to that obtained in water. For methanol analysis, acetonitrile and refined acetone gave similar δ(13) C values to that obtained in water, but n-hexane was not a suitable solvent. In addition, isotopic fractionation caused by solvent and solute interactions was observed. We recommend using acetonitrile for the GC/IRMS analysis of aqueous alcoholic samples, and acetone for the analysis of aqueous acetic acid samples. This direct dilution method can provide high accurate and precise GC/IRMS analysis of the relative changes in δ(13) C values of methanol, ethanol, and acetic acid. Copyright © 2014 John Wiley & Sons, Ltd.

Investigation of transition from thermal- to solutal-Marangoni flow in dilute alcohol/water mixtures using nano-plasmonic heaters

NASA Astrophysics Data System (ADS)

Namura, Kyoko; Nakajima, Kaoru; Suzuki, Motofumi

2018-02-01

We experimentally investigated Marangoni flows around a microbubble in diluted 1-butanol/water, 2-propanol/water, and ethanol/water mixtures using the thermoplasmonic effect of gold nanoisland film. A laser spot on the gold nanoisland film acted as a highly localized heat source that was utilized to generate stable air microbubbles with diameters of 32-48 μm in the fluid and to induce a steep temperature gradient on the bubble surface. The locally heated bubble has a flow along the bubble surface, with the flow direction showing a clear transition depending on the alcohol concentrations. The fluid is driven from the hot to cold regions when the alcohol concentration is lower than the transition concentration, whereas it is driven from the cold to hot regions when the concentration is higher than the transition concentration. In addition, the transition concentration increases as the carbon number of the alcohol decreases. The observed flow direction transition is explained by the balance of the thermal- and solutal-Marangoni forces that are cancelled out for the transition concentration. The selective evaporation of the alcohol at the locally heated surface allows us to generate stable and rapid thermoplasmonic solutal-Marangoni flows in the alcohol/water mixtures.

Monetite formed in mixed solvents of water and ethylene glycol and its transformation to hydroxyapatite.

PubMed

Ma, Ming-Guo; Zhu, Ying-Jie; Chang, Jiang

2006-07-27

Agglomerated nanorods of hydroxyapatite have been synthesized using monetite as a precursor in a NaOH solution. Monetite consisting of nanosheets has been successfully synthesized by a one-step microwave-assisted method using CaCl(2).2.5H(2)O, NaH(2)PO(4), and sodium dodecyl sulfate (SDS) in water/ethylene glycol (EG) mixed solvents. The effects of the molar ratio of water to EG and the reaction time on the products were investigated. The products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectrometry (FTIR).

Solvent effect on the rate of reaction of arsenic trisulfide with diethylamine

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

Mikhailov, M.D.

1986-06-01

The author measures the rate of solution of arsenic trisulfide films in solutions of diethylamine in protonic solvents: aliphatic alcohols and water. The transmission was measured at a wavelength of 470 nm; the absorption coefficient of glassy As/sub 2/S/sub 3/ at this wavelength is alpha - 4 x 10/sup 4/ cm/sup -1/. Studies were carried out using freshly deposited films, films irradiated with unfiltered light from a DRSH-500 lamp, and films stabilized by annealing at 160 deg C for 2 h. The curves obtained on dissolving differently prepared films in a 1 M solution of diethylamine in ethanol at roommore » temperature are shown; in all cases film corrosion occurs uniformly. The values of the rates of solution in diethylamine solutions are shown.« less

Thermodynamics of micelle formation in a water-alcohol solution of sodium tetradecyl sulfate

NASA Astrophysics Data System (ADS)

Shilova, S. V.; Tret'yakova, A. Ya.; Barabanov, V. P.

2016-01-01

The effects of addition of ethanol and propan-1-ol on sodium tetradecyl sulfate micelle formation in an aqueous solution are studied via microprobe fluorescence microscopy and conductometry. The critical micelle concentration, quantitative characteristics of micelles, and thermodynamic parameters of micelle formation are determined. Addition of 5-15 vol % of ethanol or 5-10 vol % of propan-1-ol is shown to result in a lower critical micelle concentration than in the aqueous solution, and in the formation of mixed spherical micelles whose sizes and aggregation numbers are less than those for the systems without alcohol. The contribution from the enthalpy factor to the free energy of sodium tetradecyl sulfate micelle formation is found to dominate in mixed solvents, in contrast to aqueous solutions.

Monitoring trihalomethanes in chlorinated waters using a dispersive liquid-liquid microextraction method with a non-chlorinated organic solvent and gas chromatography-mass spectrometry.

PubMed

Pacheco-Fernández, Idaira; Herrera-Fuentes, Ariadna; Delgado, Bárbara; Pino, Verónica; Ayala, Juan H; Afonso, Ana M

2017-03-01

The environmental monitoring of trihalomethanes (THMs) has been performed by setting up a dispersive liquid-liquid microextraction method in combination with gas chromatography (GC)-mass spectrometry (MS). The optimized method only requires ∼26 µL of decanol as extractant solvent, dissolved in ∼1 mL of acetone (dispersive solvent) for 5 mL of the environmental water containing THMs. The mixture is then subjected to vortex for 1 min and then centrifuged for 2 min at 3500 rpm. The microdroplet containing the extracted THMs is then sampled with a micro-syringe, and injected (1 µL) in the GC-MS. The method is characterized for being fast (3 min for the entire sample preparation step) and environmentally friendly (low amounts of solvents required, being all non-chlorinated), and also for getting average relative recoveries of 90.2-106% in tap waters; relative standard deviation values always lower than 11%; average enrichment factors of 48-49; and detection limits down to 0.7 µg·L-1. Several waters: tap waters, pool waters, and wastewaters were successfully analyzed with the method proposed. Furthermore, the method was used to monitor the formation of THMs in wastewaters when different chlorination parameters, namely temperature and pH, were varied.

Organic solvent regeneration of granular activated carbon

NASA Astrophysics Data System (ADS)

Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

1982-09-01

The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

Large-Scale Synthesis of Tin-Doped Indium Oxide Nanofibers Using Water as Solvent

NASA Astrophysics Data System (ADS)

Altecor, Aleksey; Mao, Yuanbing; Lozano, Karen

2012-09-01

Here we report the successful fabrication of tin-doped indium oxide (ITO) nanofibers using a scalable Forcespinning™ method. In this environmentally-friendly process, water was used as the only solvent for both Polyvinylpyrrolidone (PVP, the sacrificial polymer) and the metal chloride precursor salts. The obtained precursor nanofiber mats were calcinated at temperatures ranging from 500-800°C to produce ITO nanofibers with diameters as small as 400 nm. The developed ITO nanofibers were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction analysis.

Final Report - Energy Reduction and Advanced Water Removal via Membrane Solvent Extraction Technology

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

Reed, John; Fanselow, Dan; Abbas, Charles

2014-08-06

3M and Archer Daniels Midland (ADM) collaborated with the U.S. Department of Energy (DOE) to develop and demonstrate a novel membrane solvent extraction (MSE) process that can substantially reduce energy and water consumption in ethanol production, and accelerate the fermentation process. A cross-flow membrane module was developed, using porous membrane manufactured by 3M. A pilot process was developed that integrates fermentation, MSE and vacuum distillation. Extended experiments of 48-72 hours each were conducted to develop the process, verify its performance and begin establishing commercial viability.

Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors

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

Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

1999-05-19

The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage ("-OH") of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an arraymore » to distinguish the responses to methanol-water mixtures.« less

Organic Solvent Effects in Biomass Conversion Reactions.

PubMed

Shuai, Li; Luterbacher, Jeremy

2016-01-01

Transforming lignocellulosic biomass into fuels and chemicals has been intensely studied in recent years. A large amount of work has been dedicated to finding suitable solvent systems, which can improve the transformation of biomass into value-added chemicals. These efforts have been undertaken based on numerous research results that have shown that organic solvents can improve both conversion and selectivity of biomass to platform molecules. We present an overview of these organic solvent effects, which are harnessed in biomass conversion processes, including conversion of biomass to sugars, conversion of sugars to furanic compounds, and production of lignin monomers. A special emphasis is placed on comparing the solvent effects on conversion and product selectivity in water with those in organic solvents while discussing the origins of the differences that arise. We have categorized results as benefiting from two major types of effects: solvent effects on solubility of biomass components including cellulose and lignin and solvent effects on chemical thermodynamics including those affecting reactants, intermediates, products, and/or catalysts. Finally, the challenges of using organic solvents in industrial processes are discussed from the perspective of solvent cost, solvent stability, and solvent safety. We suggest that a holistic view of solvent effects, the mechanistic elucidation of these effects, and the careful consideration of the challenges associated with solvent use could assist researchers in choosing and designing improved solvent systems for targeted biomass conversion processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Critical behavior in the system cyclopentanone + water + secondary butyl alcohol

NASA Astrophysics Data System (ADS)

Krishna, U. Santhi; Unni, P. K. Madhavan

2018-05-01

We report detailed measurements of coexistence surface in the ternary system cylcopentanone + water + secondary butyl alcohol. The coexistence surface is seen to have an unusual tunnel like feature and is a potential system in which special critical points such as the Quadruple Critical Point (QCP) could be studied. Analysis of coexistence curves indicates that the system shows 3D-Ising like critical behavior.

21 CFR 173.240 - Isopropyl alcohol.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Isopropyl alcohol. 173.240 Section 173.240 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Solvents, Lubricants, Release Agents and...

Free energy landscape of protein folding in water: explicit vs. implicit solvent.

PubMed

Zhou, Ruhong

2003-11-01

The Generalized Born (GB) continuum solvent model is arguably the most widely used implicit solvent model in protein folding and protein structure prediction simulations; however, it still remains an open question on how well the model behaves in these large-scale simulations. The current study uses the beta-hairpin from C-terminus of protein G as an example to explore the folding free energy landscape with various GB models, and the results are compared to the explicit solvent simulations and experiments. All free energy landscapes are obtained from extensive conformation space sampling with a highly parallel replica exchange method. Because solvation model parameters are strongly coupled with force fields, five different force field/solvation model combinations are examined and compared in this study, namely the explicit solvent model: OPLSAA/SPC model, and the implicit solvent models: OPLSAA/SGB (Surface GB), AMBER94/GBSA (GB with Solvent Accessible Surface Area), AMBER96/GBSA, and AMBER99/GBSA. Surprisingly, we find that the free energy landscapes from implicit solvent models are quite different from that of the explicit solvent model. Except for AMBER96/GBSA, all other implicit solvent models find the lowest free energy state not the native state. All implicit solvent models show erroneous salt-bridge effects between charged residues, particularly in OPLSAA/SGB model, where the overly strong salt-bridge effect results in an overweighting of a non-native structure with one hydrophobic residue F52 expelled from the hydrophobic core in order to make better salt bridges. On the other hand, both AMBER94/GBSA and AMBER99/GBSA models turn the beta-hairpin in to an alpha-helix, and the alpha-helical content is much higher than the previously reported alpha-helices in an explicit solvent simulation with AMBER94 (AMBER94/TIP3P). Only AMBER96/GBSA shows a reasonable free energy landscape with the lowest free energy structure the native one despite an erroneous salt

Occupational solvent exposure and brain function: an fMRI study.

PubMed

Tang, Cheuk Ying; Carpenter, David M; Eaves, Emily L; Ng, Johnny; Ganeshalingam, Nimalya; Weisel, Clifford; Qian, Hua; Lange, Gudrun; Fiedler, Nancy L

2011-07-01

Deficits in cognitive function have been demonstrated among workers chronically exposed to solvents, but the neural basis for these deficits has not been shown. We used functional magnetic resonance imaging (fMRI) to compare pathophysiological changes in brain function between solvent-exposed and control workers. Painters, drywall tapers, and carpenters were recruited from the International Union of Painters and Allied Trades, District Council 9 in New York City and District Council 21 in Philadelphia, Pennsylvania, and from the Carpenters Union in New Jersey. Twenty-seven solvent-exposed and 27 control subjects of similar age, education, and occupational status completed the N-Back working memory test during fMRI. After controlling for confounders (age; lifetime marijuana, cocaine, and alcohol use; blood lead; symptoms of depression; verbal intelligence), voxelwise group analysis and regional activation levels were compared and then correlated with an index of lifetime solvent exposure. Solvent-exposed workers' performance on the N-Back was significantly worse than that of controls. Activation of the anterior cingulate, prefrontal, and parietal cortices--areas serving working memory function and attention--was also significantly lower for solvent-exposed workers relative to controls. After controlling for confounders, we observed a negative correlation between lifetime solvent exposure and activation in these same regions among the solvent-exposed workers. This study is one of the few to document neural structures affected by exposure to solvents. Our findings provide a biological mechanism for the neurobehavioral deficits in working memory and attention that have previously been reported by other groups studying the effects of chronic exposure to solvents. These imaging markers, which are consistent with the neurobehavioral measures in our subject population, are consistent with altered brain pathology caused by prolonged exposure to solvent mixtures during

Occupational Solvent Exposure and Brain Function: An fMRI Study

PubMed Central

Carpenter, David M.; Eaves, Emily L.; Ng, Johnny; Ganeshalingam, Nimalya; Weisel, Clifford; Qian, Hua; Lange, Gudrun; Fiedler, Nancy L.

2011-01-01

Background: Deficits in cognitive function have been demonstrated among workers chronically exposed to solvents, but the neural basis for these deficits has not been shown. Objectives: We used functional magnetic resonance imaging (fMRI) to compare pathophysiological changes in brain function between solvent-exposed and control workers. Methods: Painters, drywall tapers, and carpenters were recruited from the International Union of Painters and Allied Trades, District Council 9 in New York City and District Council 21 in Philadelphia, Pennsylvania, and from the Carpenters Union in New Jersey. Twenty-seven solvent-exposed and 27 control subjects of similar age, education, and occupational status completed the N-Back working memory test during fMRI. After controlling for confounders (age; lifetime marijuana, cocaine, and alcohol use; blood lead; symptoms of depression; verbal intelligence), voxelwise group analysis and regional activation levels were compared and then correlated with an index of lifetime solvent exposure. Results: Solvent-exposed workers’ performance on the N-Back was significantly worse than that of controls. Activation of the anterior cingulate, prefrontal, and parietal cortices—areas serving working memory function and attention—was also significantly lower for solvent-exposed workers relative to controls. After controlling for confounders, we observed a negative correlation between lifetime solvent exposure and activation in these same regions among the solvent-exposed workers. Conclusions: This study is one of the few to document neural structures affected by exposure to solvents. Our findings provide a biological mechanism for the neurobehavioral deficits in working memory and attention that have previously been reported by other groups studying the effects of chronic exposure to solvents. These imaging markers, which are consistent with the neurobehavioral measures in our subject population, are consistent with altered brain pathology

EFFECT OF SOLVENTS IN WATER ON ELECTROCATALYTIC DECHLORINATION OF 2-CL BP AT A PALLADIUM MODIFIED GRANULAR-GRAPHITE ELECTRODE

EPA Science Inventory

Remediation of soils and sediments contaminated by polychlorinated biphenyls (PCBs) usually involves use of organic solvents because PCBs have very limited solubility in water. The resulting liquids require further treatment to degrade these toxic contaminants. Catalytic and elec...

Quick setting water-compatible furfuryl alcohol polymer concretes

DOEpatents

Sugama, Toshifumi; Kukacka, Lawrence E.; Horn, William H.

1982-11-30

A novel quick setting polymer concrete composite comprising a furfuryl alcohol monomer, an aggregate containing a maximum of 8% by weight water, and about 1-10% trichlorotoluene initiator and about 20-80% powdered metal salt promoter, such as zinc chloride, based on the weight of said monomer, to initiate and promote polymerization of said monomer in the presence of said aggregate, within 1 hour after mixing at a temperature of -20.degree. C. to 40.degree. C., to produce a polymer concrete having a 1 hour compressive strength greater than 2000 psi.

Effect of solvent evaporation and coagulation on morphology development of asymmetric membranes

NASA Astrophysics Data System (ADS)

Chandrasekaran, Neelakandan; Kyu, Thein

2008-03-01

Miscibility behavior of blends of amorphous polyamide (PA) and polyvinylpyrrolidone (PVP) was studied in relation to membrane formation. Dimethylsulfoxide (DMSO) and water were used as solvent and non-solvent, respectively. Differential scanning calorimetry and cloud point measurements revealed that the binary PA/PVP blends as well as the ternary PA/PVP/DMSO system were completely miscible at all compositions. However, the addition of non-solvent (water) to this ternary system has led to phase separation. Visual turbidity study was used to establish a ternary liquid-liquid phase diagram of the PA-PVP/DMSO/water system. Scanning Electron Microscopy (SEM) showed the development of finger-like and sponge-like cross sectional morphologies during coagulation. Effects of polymer concentration, PA/PVP blend ratio, solvent/non-solvent quality, and evaporation time on the resulting membrane morphology will be discussed.

Deuterium isotope effects on methyl transfer to alcohols. Possible asynchronous solvent repolarization and internal structural changes

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

Kurz, J.L.; Lee, J.; Rhodes, S.

1981-12-16

Alkyl substitution on nucleophilic oxygen causes large changes in the H/sub 2/O/D/sub 2/O kinetic isotope effect (KIE) on methyl transfers to water: ROL + CH/sub 3/X..-->.. RLO/sup +/ CH/sub 3/ + X/sup -/ with L=H,D; R=L. For both Meth/sup +/ and MeOClO/sub 3/, KIE for CH/sub 3/OL is greater than KIE for L/sub 2/O. When the methyl transfer is to L/sub 2/O, the small, strongly hydrogen-bonding L/sub 2/O/sup +/ moiety in the product will be very tightly solvated, and such tight solvation implies a strong coupling force between solvent polarization and internal charge distribution. (MWF)

Optimization of nanolime solvent for the consolidation of coarse porous limestone

NASA Astrophysics Data System (ADS)

Borsoi, Giovanni; Lubelli, Barbara; van Hees, Rob; Veiga, Rosário; Silva, António Santos

2016-09-01

The potentialities of nanomaterials for application in the field of conservation have been widely investigated in the last two decades. Among nanomaterials, nanolimes, i.e., dispersions of lime nanoparticles in alcohols are promising consolidating products for calcareous materials. Nanolimes are effective in recovering the very superficial loss of cohesion of decayed materials, but they do not always provide sufficient mass consolidation. This limitation is mainly related to the deposition of the nanoparticles nearby the surface of the material. Experimental research has been set up with the aim of improving the in-depth deposition of lime nanoparticles. Previous research by the authors has shown that nanolime deposition within a substrate can be controlled by adapting the nanolimes properties (kinetic stability and evaporation rate) to the moisture transport behavior of the substrate. Nanolime properties can be modified by the use of different solvents. In this research, nanolime dispersions have been further optimized for application on Maastricht limestone, a coarse porous limestone. Firstly, nanolimes were synthesized and dispersed in ethanol and/or water, both pure and mixed in different percentages. Subsequently, based on the kinetic stability of the nanolime dispersions, the most promising solvent mixtures were selected and applied on the limestone. The deposition of lime nanoparticles within the limestone was studied by phenolphthalein test, optical microscopy and scanning electron microscopy. The results confirm that nanolime dispersed in a mixture of ethanol (95 %) and water (5 %) can guarantee a better nanoparticles in-depth deposition within coarse porous substrates, when compared to dispersions in pure ethanol.

Prediction of Water Binding to Protein Hydration Sites with a Discrete, Semiexplicit Solvent Model.

PubMed

Setny, Piotr

2015-12-08

Buried water molecules are ubiquitous in protein structures and are found at the interface of most protein-ligand complexes. Determining their distribution and thermodynamic effect is a challenging yet important task, of great of practical value for the modeling of biomolecular structures and their interactions. In this study, we present a novel method aimed at the prediction of buried water molecules in protein structures and estimation of their binding free energies. It is based on a semiexplicit, discrete solvation model, which we previously introduced in the context of small molecule hydration. The method is applicable to all macromolecular structures described by a standard all-atom force field, and predicts complete solvent distribution within a single run with modest computational cost. We demonstrate that it indicates positions of buried hydration sites, including those filled by more than one water molecule, and accurately differentiates them from sterically accessible to water but void regions. The obtained estimates of water binding free energies are in fair agreement with reference results determined with the double decoupling method.

Solvent and α-secondary kinetic isotope effects on β-glucosidase.

PubMed

Xie, Miaomiao; Byers, Larry D

2015-11-01

β-Glucosidase from sweet almond is a retaining, family 1, glycohydrolase. It is known that glycosylation of the enzyme by aryl glucosides occurs with little, if any, acid catalysis. For this reaction both the solvent and α-secondary kinetic isotope effects are 1.0. However, for the deglucosylation reaction (e.g., kcat for 2,4-dinitrophenyl-β-D-glucopyranoside) there is a small solvent deuterium isotope effect of 1.50 (±0.06) and an α-secondary kinetic isotope effect of 1.12 (±0.03). For aryl glucosides, kcat/KM is very sensitive to the pKa of the phenol leaving group [βlg≈-1; Dale et al., Biochemistry25 (1986) 2522-2529]. With alkyl glucosides the βlg is smaller (between -0.2 and -0.3) but still negative. This, coupled with the small solvent isotope effect on the pH-independent second-order rate constant for the glucosylation of the enzyme with 2,2,2-trifluoroethyl-β-glucoside [D2O(kcat/KM)=1.23 (±0.04)] suggests that there is more glycone-aglycone bond fission than aglycone oxygen protonation in the transition state for alkyl glycoside hydrolysis. The kinetics constants for the partitioning (between water and various alcohols) of the glucosyl-enzyme intermediate, coupled with the rate constants for the forward (hydrolysis) reaction provide an estimate of the stability of the glucosyl-enzyme intermediate. This is a relatively stable species with an energy about 2 to 4 kcal/mol higher than that of the ES complex. This article is part of a Special Issue entitled: Enzyme Transition States from Theory and Experiment. Copyright © 2015 Elsevier B.V. All rights reserved.

Photophysical properties of a new series of water soluble iridium bisterpyridine complexes functionalised at the 4' position.

PubMed

Goldstein, Daniel C; Cheng, Yuen Yap; Schmidt, Timothy W; Bhadbhade, Mohan; Thordarson, Pall

2011-03-07

Four new hetero- and homo-leptic iridium(III) bisterpyridine complexes have been prepared which incorporate aniline (tpy-φ-NH(2)), benzoic acid (tpy-φ-COOH), and benzyl alcohol (tpy-φ-CH(2)OH) substituents at the 4' positions of the tpy ligands (tpy = 2,2':6',2''-terpyridine, φ = phenylene). The electrochemical behaviour and ground and excited state spectroscopic properties of the complexes are reported, and the X-ray crystal structures of a homoleptic benzyl alcohol [Ir(tpy-φ-CH(2)OH)(2)](PF(6))(3), homoleptic aniline [Ir(tpy-φ-NH(2))(2)](PF(6))(3), and heteroleptic benzyl alcohol/aniline substituted complex [Ir(tpy-φ-CH(2)OH)(tpy-φ-NH(2))](PF(6))(3) have been solved. Complexes with aniline substituents were found to display absorption bands at around 430 nm corresponding to intraligand charge transfer (ILCT) that are sensitive to changes in solvent and pH. Strong emission in the visible region involving the ILCT state is observed in two of the complexes (Φ(e) = 0.7% and 2.6%) in acetonitrile. In the heteroleptic aniline/benzyl alcohol complex the Stokes shift is shown to be linearly related to solvent polarisability according to the Lippert equation, but only for solvents with weak hydrogen bonding interactions. Additionally, in water, emission from the ILCT state is quenched and only weak ligand centred (LC) emission is observed. The long lifetimes and quantum yields of these complexes make them interesting candidates for probes in sensing applications, especially [Ir(tpy-φ-CH(2)OH)(tpy-φ-NH(2))(2)](PF(6))(3) due to its unusual sensitivity to the solvent environment.

Rapid Covalent Modification of Silicon Oxide Surfaces through Microwave-Assisted Reactions with Alcohols.

PubMed

Lee, Austin W H; Gates, Byron D

2016-07-26

We demonstrate the method of a rapid covalent modification of silicon oxide surfaces with alcohol-containing compounds with assistance by microwave reactions. Alcohol-containing compounds are prevalent reagents in the laboratory, which are also relatively easy to handle because of their stability against exposure to atmospheric moisture. The condensation of these alcohols with the surfaces of silicon oxides is often hindered by slow reaction kinetics. Microwave radiation effectively accelerates this condensation reaction by heating the substrates and/or solvents. A variety of substrates were modified in this demonstration, such as silicon oxide films of various thicknesses, glass substrates such as microscope slides (soda lime), and quartz. The monolayers prepared through this strategy demonstrated the successful formation of covalent surface modifications of silicon oxides with water contact angles of up to 110° and typical hysteresis values of 2° or less. An evaluation of the hydrolytic stability of these monolayers demonstrated their excellent stability under acidic conditions. The techniques introduced in this article were successfully applied to tune the surface chemistry of silicon oxides to achieve hydrophobic, oleophobic, and/or charged surfaces.

Measuring the Absorption Rate of CO 2 in Nonaqueous CO 2 -Binding Organic Liquid Solvents with a Wetted-Wall Apparatus

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

Mathias, Paul M.; Zheng, Feng; Heldebrant, David J.

2015-09-17

The kinetics of the absorption of CO 2 into two nonaqueous CO 2-binding organic liquid (CO 2BOL) solvents were measured at T=35, 45, and 55 °C with a wetted-wall column. Selected CO 2 loadings were run with a so-called “first-generation” CO 2BOL, comprising an independent base and alcohol, and a “second-generation” CO 2BOL, in which the base and alcohol were conjoined. Liquid-film mass-transfer coefficient (k'g) values for both solvents were measured to be comparable to values for monoethanolamine and piperazine aqueous solvents under a comparable driving force, in spite of far higher solution viscosities. An inverse temperature dependence of themore » k'g value was also observed, which suggests that the physical solubility of CO 2 in organic liquids may be making CO 2 mass transfer faster than expected. Aspen Plus software was used to model the kinetic data and compare the CO 2 absorption behavior of nonaqueous solvents with that of aqueous solvent platforms. This work continues our development of the CO2BOL solvents. Previous work established the thermodynamic properties related to CO 2 capture. The present paper quantitatively studies the kinetics of CO 2 capture and develops a rate-based model.« less

Supramolecular solvent-based extraction of benzimidazolic fungicides from natural waters prior to their liquid chromatographic/fluorimetric determination.

PubMed

Moral, Antonia; Sicilia, María Dolores; Rubio, Soledad

2009-05-01

A supramolecular solvent made up of vesicles of decanoic acid in the nano- and microscale regimes dispersed in a continuous aqueous phase is proposed for the extraction/preconcentration of benzimidazolic fungicides (BFs) from river and underground water samples prior to their determination by liquid chromatography (LC)/fluorimetry. The solvent is produced from the coacervation of decanoic acid aqueous vesicles by the action of tetrabutylammonium (Bu(4)N(+)). Carbendazim (CB), thiabendazole (TB) and fuberidazole (FB) are extracted on the basis of hydrophobic and pi-cation interactions and the formation of hydrogen bonds. The extraction provides high preconcentration factors (160 for CB and 190 for TB and FB), requires a short time (the procedure takes less than 20 min and several samples can be simultaneously processed) and a low sample volume (20 mL), and avoids the use of toxic organic solvents. Because of the absence of matrix interferences and the low viscosity of the extracts, these can be directly injected into the chromatographic system without the need of cleaning-up or diluting them. Recoveries are not influenced by the presence of salt concentrations up to 1 M. The proposed method provides detection limits for the determination of CB, TB and FB in natural waters of 32, 4 and 0.1 ng L(-1), respectively, and a precision, expressed as relative standard deviation (n=11) of 5.5% for CB (100 ng L(-1)), 4.0% for TB (80 ng L(-1)) and 2.5% for FB (30 ng L(-1)). Recoveries obtained by applying this approach to the analysis of river and underground water samples fortified at the ng L(-1) level are in the intervals 75-83, 95-102 and 97-101% for CB, TB and FB, respectively.

Central auditory processing effects induced by solvent exposure.

PubMed

Fuente, Adrian; McPherson, Bradley

2007-01-01

Various studies have demonstrated that organic solvent exposure may induce auditory damage. Studies conducted in workers occupationally exposed to solvents suggest, on the one hand, poorer hearing thresholds than in matched non-exposed workers, and on the other hand, central auditory damage due to solvent exposure. Taking into account the potential auditory damage induced by solvent exposure due to the neurotoxic properties of such substances, the present research aimed at studying the possible auditory processing disorder (APD), and possible hearing difficulties in daily life listening situations that solvent-exposed workers may acquire. Fifty workers exposed to a mixture of organic solvents (xylene, toluene, methyl ethyl ketone) and 50 non-exposed workers matched by age, gender and education were assessed. Only subjects with no history of ear infections, high blood pressure, kidney failure, metabolic and neurological diseases, or alcoholism were selected. The subjects had either normal hearing or sensorineural hearing loss, and normal tympanometric results. Hearing-in-noise (HINT), dichotic digit (DD), filtered speech (FS), pitch pattern sequence (PPS), and random gap detection (RGD) tests were carried out in the exposed and non-exposed groups. A self-report inventory of each subject's performance in daily life listening situations, the Amsterdam Inventory for Auditory Disability and Handicap, was also administered. Significant threshold differences between exposed and non-exposed workers were found at some of the hearing test frequencies, for both ears. However, exposed workers still presented normal hearing thresholds as a group (equal or better than 20 dB HL). Also, for the HINT, DD, PPS, FS and RGD tests, non-exposed workers obtained better results than exposed workers. Finally, solvent-exposed workers reported significantly more hearing complaints in daily life listening situations than non-exposed workers. It is concluded that subjects exposed to solvents

Solvent-shared pairs of densely charged ions induce intense but short-range supra-additive slowdown of water rotation.

PubMed

Vila Verde, Ana; Santer, Mark; Lipowsky, Reinhard

2016-01-21

The question "Can ions exert supra-additive effects on water dynamics?" has had several opposing answers from both simulation and experiment. We address this ongoing controversy by investigating water reorientation in aqueous solutions of two salts with large (magnesium sulfate) and small (cesium chloride) effects on water dynamics using molecular dynamics simulations and classical, polarizable models. The salt models are reparameterized to reproduce properties of both dilute and concentrated solutions. We demonstrate that water rotation in concentrated MgSO4 solutions is unexpectedly slow, in agreement with experiment, and that the slowdown is supra-additive: the observed slowdown is larger than that predicted by assuming that the resultant of the extra forces induced by the ions on the rotating water molecules tilts the free energy landscape associated with water rotation. Supra-additive slow down is very intense but short-range, and is strongly ion-specific: in contrast to the long-range picture initially proposed based on experiment, we find that intense supra-additivity is limited to water molecules directly bridging two ions in solvent-shared ion pair configuration; in contrast to a non-ion-specific origin to supra-additive effects proposed from simulations, we find that the magnitude of supra-additive slowdown strongly depends on the identity of the cations and anions. Supra-additive slowdown of water dynamics requires long-lived solvent-shared ion pairs; long-lived ion pairs should be typical for salts of multivalent ions. We discuss the origin of the apparent disagreement between the various studies on this topic and show that the short-range cooperative slowdown scenario proposed here resolves the existing controversy.

Optimization of soy isoflavone extraction with different solvents using the simplex-centroid mixture design.

PubMed

Yoshiara, Luciane Yuri; Madeira, Tiago Bervelieri; Delaroza, Fernanda; da Silva, Josemeyre Bonifácio; Ida, Elza Iouko

2012-12-01

The objective of this study was to optimize the extraction of different isoflavone forms (glycosidic, malonyl-glycosidic, aglycone and total) from defatted cotyledon soy flour using the simplex-centroid experimental design with four solvents of varying polarity (water, acetone, ethanol and acetonitrile). The obtained extracts were then analysed by high-performance liquid chromatography. The profile of the different soy isoflavones forms varied with different extractions solvents. Varying the solvent or mixture used, the extraction of different isoflavones was optimized using the centroid-simplex mixture design. The special cubic model best fitted to the four solvents and its combination for soy isoflavones extraction. For glycosidic isoflavones extraction, the polar ternary mixture (water, acetone and acetonitrile) achieved the best extraction; malonyl-glycosidic forms were better extracted with mixtures of water, acetone and ethanol. Aglycone isoflavones, water and acetone mixture were best extracted and total isoflavones, the best solvents were ternary mixture of water, acetone and ethanol.

Solvent Dependence of Lateral Charge Transfer in a Porphyrin Monolayer

DOE PAGES

Brennan, Bradley J.; Regan, Kevin P.; Durrell, Alec C.; ...

2016-12-19

Lateral charge transport in a redox)active monolayer can be utilized for solar energy harvesting. We chose the porphyrin system to study the influence of the solvent on lateral hole hopping, which plays a crucial role in the charge)transfer kinetics. We also examined the influence of water, acetonitrile, and propylene carbonate as solvents. Hole)hopping lifetimes varied by nearly three orders of magnitude among solvents, ranging from 3 ns in water to 2800 ns in propylene carbonate, and increased nonlinearly as a function of added acetonitrile in aqueous solvent mixtures. Our results elucidate the important roles of solvation, molecular packing dynamics, andmore » lateral charge)transfer mechanisms that have implications for all dye)sensitized photoelectrochemical device designs.« 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.

Oven Evaporates Isopropyl Alcohol Without Risk Of Explosion

NASA Technical Reports Server (NTRS)

Morgan, Gene E.; Hoult, William S.

1996-01-01

Ordinary convection oven with capacity of 1 ft.(sup3) modified for use in drying objects washed in isopropyl alcohol. Nitrogen-purge equipment and safety interlocks added to prevent explosive ignition of flammable solvent evaporating from object to be dried.

Fire extinguishing tests -80 with methyl alcohol gasoline

NASA Astrophysics Data System (ADS)

Holmstedt, G.; Ryderman, A.; Carlsson, B.; Lennmalm, B.

1980-10-01

Large scale tests and laboratory experiments were carried out for estimating the extinguishing effectiveness of three alcohol resistant aqueous film forming foams (AFFF), two alcohol resistant fluoroprotein foams and two detergent foams in various poolfires: gasoline, isopropyl alcohol, acetone, methyl-ethyl ketone, methyl alcohol and M15 (a gasoline, methyl alcohol, isobutene mixture). The scaling down of large scale tests for developing a reliable laboratory method was especially examined. The tests were performed with semidirect foam application, in pools of 50, 11, 4, 0.6, and 0.25 sq m. Burning time, temperature distribution in the liquid, and thermal radiation were determined. An M15 fire can be extinguished with a detergent foam, but it is impossible to extinguish fires in polar solvents, such as methyl alcohol, acetone, and isopropyl alcohol with detergent foams, AFFF give the best results; and performances with small pools can hardly be correlated with results from large scale fires.

Switchable hydrophilicity solvents for lipid extraction from microalgae for biofuel production.

PubMed

Boyd, Alaina R; Champagne, Pascale; McGinn, Patrick J; MacDougall, Karen M; Melanson, Jeremy E; Jessop, Philip G

2012-08-01

A switchable hydrophilicity solvent (SHS) was studied for its effectiveness at extracting lipids from freeze-dried samples of Botryococcus braunii microalgae. The SHS N,N-dimethylcyclohexylamine extracted up to 22 wt.% crude lipid relative to the freeze-dried cell weight. The solvent was removed from the extract with water saturated with carbon dioxide at atmospheric pressure and recovered from the water upon de-carbonation of the mixture. Liquid chromatography-mass spectrometry (LC-MS) showed that the extracted lipids contained high concentrations of long chain tri-, di- and mono-acylglycerols, no phospholipids, and only 4-8% of residual solvent. Unlike extractions with conventional organic solvents, this new method requires neither distillation nor the use of volatile, flammable or chlorinated organic solvents. Copyright © 2012 Elsevier Ltd. All rights reserved.

27 CFR 30.66 - Table 6, showing respective volumes of alcohol and water and the specific gravity in both air and...

Code of Federal Regulations, 2012 CFR

2012-04-01

... respective volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor... volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor. This... gallon of water in air by the specific gravity in air of the spirits—8.32823 by 0.88862—the product (7...

27 CFR 30.66 - Table 6, showing respective volumes of alcohol and water and the specific gravity in both air and...

Code of Federal Regulations, 2010 CFR

2010-04-01

... respective volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor... volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor. This... gallon of water in air by the specific gravity in air of the spirits—8.32823 by 0.88862—the product (7...

27 CFR 30.66 - Table 6, showing respective volumes of alcohol and water and the specific gravity in both air and...

Code of Federal Regulations, 2011 CFR

2011-04-01

... respective volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor... volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor. This... gallon of water in air by the specific gravity in air of the spirits—8.32823 by 0.88862—the product (7...

27 CFR 30.66 - Table 6, showing respective volumes of alcohol and water and the specific gravity in both air and...

Code of Federal Regulations, 2013 CFR

2013-04-01

... respective volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor... volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor. This... gallon of water in air by the specific gravity in air of the spirits—8.32823 by 0.88862—the product (7...

27 CFR 30.66 - Table 6, showing respective volumes of alcohol and water and the specific gravity in both air and...

Code of Federal Regulations, 2014 CFR

2014-04-01

... respective volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor... volumes of alcohol and water and the specific gravity in both air and vacuum of spirituous liquor. This... gallon of water in air by the specific gravity in air of the spirits—8.32823 by 0.88862—the product (7...

Moving zone Marangoni drying of wet objects using naturally evaporated solvent vapor

DOEpatents

Britten, Jerald A.

1997-01-01

A surface tension gradient driven flow (a Marangoni flow) is used to remove the thin film of water remaining on the surface of an object following rinsing. The process passively introduces by natural evaporation and diffusion of minute amounts of alcohol (or other suitable material) vapor in the immediate vicinity of a continuously refreshed meniscus of deionized water or another aqueous-based, nonsurfactant rinsing agent. Used in conjunction with cleaning, developing or wet etching application, rinsing coupled with Marangoni drying provides a single-step process for 1) cleaning, developing or etching, 2) rinsing, and 3) drying objects such as flat substrates or coatings on flat substrates without necessarily using heat, forced air flow, contact wiping, centrifugation or large amounts of flammable solvents. This process is useful in one-step cleaning and drying of large flat optical substrates, one-step developing/rinsing and drying or etching/rinsing/drying of large flat patterned substrates and flat panel displays during lithographic processing, and room-temperature rinsing/drying of other large parts, sheets or continuous rolls of material.

Moving zone Marangoni drying of wet objects using naturally evaporated solvent vapor

DOEpatents

Britten, J.A.

1997-08-26

A surface tension gradient driven flow (a Marangoni flow) is used to remove the thin film of water remaining on the surface of an object following rinsing. The process passively introduces by natural evaporation and diffusion of minute amounts of alcohol (or other suitable material) vapor in the immediate vicinity of a continuously refreshed meniscus of deionized water or another aqueous-based, nonsurfactant rinsing agent. Used in conjunction with cleaning, developing or wet etching application, rinsing coupled with Marangoni drying provides a single-step process for (1) cleaning, developing or etching, (2) rinsing, and (3) drying objects such as flat substrates or coatings on flat substrates without necessarily using heat, forced air flow, contact wiping, centrifugation or large amounts of flammable solvents. This process is useful in one-step cleaning and drying of large flat optical substrates, one-step developing/rinsing and drying or etching/rinsing/drying of large flat patterned substrates and flat panel displays during lithographic processing, and room-temperature rinsing/drying of other large parts, sheets or continuous rolls of material. 5 figs.

High throughput research and evaporation rate modeling for solvent screening for ethylcellulose barrier membranes in pharmaceutical applications.

PubMed

Schoener, Cody A; Curtis-Fisk, Jaime L; Rogers, True L; Tate, Michael P

2016-10-01

Ethylcellulose is commonly dissolved in a solvent or formed into an aqueous dispersion and sprayed onto various dosage forms to form a barrier membrane to provide controlled release in pharmaceutical formulations. Due to the variety of solvents utilized in the pharmaceutical industry and the importance solvent can play on film formation and film strength it is critical to understand how solvent can influence these parameters. To systematically study a variety of solvent blends and how these solvent blends influence ethylcellulose film formation, physical and mechanical film properties and solution properties such as clarity and viscosity. Using high throughput capabilities and evaporation rate modeling, thirty-one different solvent blends composed of ethanol, isopropanol, acetone, methanol, and/or water were formulated, analyzed for viscosity and clarity, and narrowed down to four solvent blends. Brookfield viscosity, film casting, mechanical film testing and water permeation were also completed. High throughput analysis identified isopropanol/water, ethanol, ethanol/water and methanol/acetone/water as solvent blends with unique clarity and viscosity values. Evaporation rate modeling further rank ordered these candidates from excellent to poor interaction with ethylcellulose. Isopropanol/water was identified as the most suitable solvent blend for ethylcellulose due to azeotrope formation during evaporation, which resulted in a solvent-rich phase allowing the ethylcellulose polymer chains to remain maximally extended during film formation. Consequently, the highest clarity and most ductile films were formed. Employing high throughput capabilities paired with evaporation rate modeling allowed strong predictions between solvent interaction with ethylcellulose and mechanical film properties.

Solvent composition of one-step self-etch adhesives and dentine wettability.

PubMed

Grégoire, Geneviève; Dabsie, Firas; Dieng-Sarr, Farimata; Akon, Bernadette; Sharrock, Patrick

2011-01-01

Our aim was to determine the wettability of dentine by four commercial self-etch adhesives and evaluate their spreading rate on the dentine surface. Any correlation with chemical composition was sought, particularly with the amount of solvent or HEMA present in the adhesive. The adhesives used were AdheSE One, Optibond All.In.One, Adper Easy Bond and XenoV. Chemical compositions were determined by proton nuclear magnetic resonance (NMR) spectroscopy of the adhesives dissolved in dimethylsulfoxide. Apparent contact angles for sessile drops of adhesives were measured on dentine slices as a function of time for up to 180s. The water contact angles were determined for fully polymerised adhesives. All adhesives were water-based with total solvent contents ranging from 27% to 73% for HEMA-free adhesives, and averaging 45% for HEMA containing adhesives. The contents in hydrophobic groups decreased as water contents increased. No differences were found in the adhesive contact angles after 180s even though the spreading rates were different for the products tested. Water contact angles differed significantly but were not correlated with HEMA or solvent presence. Manufacturers use different approaches to stabilise acid co-monomer ingredients in self-etch adhesives. Co-solvents, HEMA, or acrylamides without co-solvents are used to simultaneously etch and infiltrate dentine. A large proportion of water is necessary for decalcification action. Copyright © 2010 Elsevier Ltd. All rights reserved.

Polymer Film Dewetting by Water/Surfactant/Good-Solvent Mixtures: A Mechanistic Insight and Its Implications for the Conservation of Cultural Heritage.

PubMed

Baglioni, Michele; Montis, Costanza; Chelazzi, David; Giorgi, Rodorico; Berti, Debora; Baglioni, Piero

2018-06-18

Aqueous nanostructured fluids (NSFs) have been proposed to remove polymer coatings from the surface of works of art; this process usually involves film dewetting. The NSF cleaning mechanism was studied using several techniques that were employed to obtain mechanistic insight on the interaction of a methacrylic/acrylic copolymer (Paraloid B72) film laid on glass surfaces and several NSFs, based on two solvents and two surfactants. The experimental results provide a detailed picture of the dewetting process. The gyration radius and the reduction of the T g of Paraloid B72 fully swollen in the two solvents is larger for propylene carbonate than for methyl ethyl ketone, suggesting higher mobility of polymer chains for the former, while a nonionic alcohol ethoxylate surfactant was more effective than sodium dodecylsulfate in favoring the dewetting process. FTIR 2D imaging showed that the dewetting patterns observed on model samples are also present on polymer-coated mortar tiles when exposed to NSFs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

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

Lam, Royce K.; Smith, Jacob W.; Saykally, Richard J., E-mail: saykally@berkeley.edu

While methanol and ethanol are macroscopically miscible with water, their mixtures exhibit negative excess entropies of mixing. Despite considerable effort in both experiment and theory, there remains significant disagreement regarding the origin of this effect. Different models for the liquid mixture structure have been proposed to address this behavior, including the enhancement of the water hydrogen bonding network around the alcohol hydrophobic groups and microscopic immiscibility or clustering. We have investigated mixtures of methanol, ethanol, and isopropanol with water by liquid microjet X-ray absorption spectroscopy on the oxygen K-edge, an atom-specific probe providing details of both inter- and intra-molecular structure.more » The measured spectra evidence a significant enhancement of hydrogen bonding originating from the methanol and ethanol hydroxyl groups upon the addition of water. These additional hydrogen bonding interactions would strengthen the liquid-liquid interactions, resulting in additional ordering in the liquid structures and leading to a reduction in entropy and a negative enthalpy of mixing, consistent with existing thermodynamic data. In contrast, the spectra of the isopropanol-water mixtures exhibit an increase in the number of broken alcohol hydrogen bonds for mixtures containing up to 0.5 water mole fraction, an observation consistent with existing enthalpy of mixing data, suggesting that the measured negative excess entropy is a result of clustering or micro-immiscibility.« less

Investigating the Synthesis and Characterization of a Novel "Green" H₂O₂-Assisted, Water-Soluble Chitosan/Polyvinyl Alcohol Nanofiber for Environmental End Uses.

PubMed

Pervez, Md Nahid; Stylios, George K

2018-06-01

The present work highlights the formation of a novel green nanofiber based on H₂O₂-assisted water-soluble chitosan/polyvinyl alcohol (W S CHT/PVA) by using water as an ecofriendly solvent and genipin used as a nontoxic cross-linker. The 20/80 blend ratio was found to have the most optimum uniform fiber morphology. W S CHT retained the same structure as W IS CHT. The prepared nanofibers were characterized by Scanning electron microscopy (SEM), Fourier transform spectroscopy (FTIR), Thermo gravimetric analysis (TGA), Differential scanning calorimeter (DSC), X-ray diffraction (XRD), Water Contact Angle (WCA) and Ultraviolet-visible spectroscopy (UV-vis). During electrospinning, the crystalline microstructure of the W S CHT/PVA underwent better solidification and after cross-linking there was an increase in the melting temperature of the fiber. Swelling ratio studies revealed noticeable increase in hydrophilicity with increase of W S CHT, which was further demonstrated by the decrease of contact angle from 64.74° to 14.68°. W S CHT/PVA nanofiber mats exhibit excellent UV blocking protection with less than 5% transmittance value and also showed improved in vitro drug release properties with stable release for longer duration (cross-linked fibers) and burst release for shorter duration (uncross linked) fibers. Finally our experimental data demonstrates excellent adsorption ability of Colour Index (C.I.) reactive black 5 (RB5) due to protonated amino groups.

Capturing the Role of Explicit Solvent in the Dimerization of RuV (bda) Water Oxidation Catalysts.

PubMed

Zhan, Shaoqi; Mårtensson, Daniel; Purg, Miha; Kamerlin, Shina C L; Ahlquist, Mårten S G

2017-06-06

A ground-breaking empirical valence bond study for a soluble transition-metal complex is presented. The full reaction of catalyst monomers approaching and reacting in the Ru V oxidation state were studied. Analysis of the solvation shell in the reactant and along the reaction coordinate revealed that the oxo itself is hydrophobic, which adds a significant driving force to form the dimer. The effect of the solvent on the reaction between the prereactive dimer and the product was small. The solvent seems to lower the barrier for the isoquinoline (isoq) complex while it is increased for pyridines. By comparing the reaction in the gas phase and solution, the proposed π-stacking interaction of the isoq ligands is found to be entirely driven by the water medium. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solvent Effects in the Electroreduction of Ferrocene at Pt in the Temperature Range 200-300 K

DTIC Science & Technology

1991-03-20

been obtained at iow temperatures downto 92 K ata P ulramcroeectode(dimete, 2 pm inthree alcohol solvents, namely, methanol, ethanol , and n-propanol. In...In this aree.-doutee-eace&4 Kinetic parameters for the electrooxidation of ferrocene have been obtained at low temperatures down to 193 ’K at a Pt...with solvent nature. tnsvetsiky of~aitm Davis, CA 95616 Kinetic data obtained in mteehanol, ethanol . and I1- propanol as a function of temperature

The development of novel Nexar block copolymer/Ultem composite membranes for C2-C4 alcohols dehydration via pervaporation.

PubMed

Zuo, Jian; Shi, Gui Min; Wei, Shawn; Chung, Tai-Shung

2014-08-27

Novel composite membranes comprising sulfonated styrenic Nexar pentablock copolymers were developed by dip-coating on poly(ether imide) hollow fibers for pervaporation dehydration of C2-C4 alcohols. The advantages of using block copolymers as the selective layer are (1) their effectiveness to synergize the physicochemical properties of different chemical and structural moieties and (2) tunable nanoscale morphology and nanostructure via molecular engineering. To achieve high-performance composite membranes, the effects of coating time, ion exchange capacity (IEC) of the copolymer, and solvent systems for coating were investigated. It is revealed that a minimum coating time of 30 s is needed for the formation of a continuous and less-defective top layer. A higher IEC value results in a membrane with a higher flux and lower separation factor because of enhanced hydrophilicity and stretched chain conformation. Moreover, the composite membranes prepared from hexane/ethanol mixtures show higher separation factors and lower fluxes than those from the hexane solvent owing to microdomain segregation induced by ethanol and a smooth and dense top selective layer. These hypotheses were verified by atomic force microscopy and positron annihilation spectroscopy. The newly developed composite membranes demonstrate impressive separation performance with fluxes exceeding 2 kg/m(2) h and separation factors more than 200 for isopropyl alcohol and n-butanol dehydration from 85/15 wt % alcohol/water feed mixtures at 50 °C.

Thermodynamic of cellulose solvation in novel solvent mixtures

NASA Astrophysics Data System (ADS)

Das, Ritankar; Chu, Jhih-Wei

2013-04-01

Biomass contains abundant amounts of cellulose as crystalline microfibrils. A limiting step to using cellulose as an alternative energy source, however, is the hydrolysis of the biomass and subsequent transformation into fuels. Cellulose is insoluble in most solvents including organic solvents and water, but it is soluble in some ionic liquids like BMIM-Cl. This project aims to find alternative solvents that are less expensive and are more environmentally benign than the ionic liquids. All-atom molecular dynamics simulations were performed on dissociated glucan chains separated by multiple (4-5) solvation shells, in the presence of several novel solvents and solvent mixtures. The solubility of the chains in each solvent was indicated by contacts calculations after the equilibration of the molecular dynamics. It was discovered that pyridine and imidazole acted as the best solvents because their aromatic electronic structure was able to effectively disrupt the inter-sheet interactions among the glucan chains in the axial direction, and because perturbation of the solvent interactions in the presence of glucan chains was minimal.

Thermodynamic of cellulose solvation in novel solvent mixtures

NASA Astrophysics Data System (ADS)

Das, Ritankar

2013-03-01

Biomass contains abundant amounts of cellulose as crystalline microfibrils. A limiting step to using cellulose as an alternative energy source, however, is the hydrolysis of the biomass and subsequent transformation into fuels. Cellulose is insoluble in most solvents including organic solvents and water, but it is soluble in some ionic liquids like BMIM-Cl. This project aims to find alternative solvents that are less expensive and are more environmentally benign than the ionic liquids. All-atom molecular dynamics simulations were performed on dissociated glucan chains separated by multiple (4-5) solvation shells, in the presence of several novel solvents and solvent mixtures. The solubility of the chains in each solvent was indicated by contacts calculations after the equilibration of the molecular dynamics. It was discovered that pyridine and imidazole acted as the best solvents because their aromatic electronic structure was able to effectively disrupt the inter-sheet interactions among the glucan chains in the axial direction, and because perturbation of the solvent interactions in the presence of glucan chains was minimal.

Thermodynamics of cellulose solvation in novel solvent mixtures

NASA Astrophysics Data System (ADS)

Das, Ritankar; Chu, Jhih-Wei

2012-10-01

Biomass contains abundant amounts of cellulose as crystalline microfibrils. A limiting step to using cellulose as an alternative energy source, however, is the hydrolysis of the biomass and subsequent transformation into fuels. Cellulose is insoluble in most solvents including organic solvents and water, but it is soluble in some ionic liquids like BMIM-Cl. This project aims to find alternative solvents that are less expensive and are more environmentally benign than the ionic liquids. All-atom molecular dynamics simulations were performed on dissociated glucan chains separated by multiple (4-5) solvation shells, in the presence of several novel solvents and solvent mixtures. The solubility of the chains in each solvent was indicated by contacts calculations after the equilibration of the molecular dynamics. It was discovered that pyridine and imidazole acted as the best solvents because their aromatic electronic structure was able to effectively disrupt the inter-sheet interactions among the glucan chains in the axial direction, and because perturbation of the solvent interactions in the presence of glucan chains was minimal.

Thermodynamic of cellulose solvation in novel solvent mixtures

NASA Astrophysics Data System (ADS)

Das, Ritankar

2012-11-01

Biomass contains abundant amounts of cellulose as crystalline microfibrils. A limiting step to using cellulose as an alternative energy source, however, is the hydrolysis of the biomass and subsequent transformation into fuels. Cellulose is insoluble in most solvents including organic solvents and water, but it is soluble in some ionic liquids like BMIM-Cl. This project aims to find alternative solvents that are less expensive and are more environmentally benign than the ionic liquids. All-atom molecular dynamics simulations were performed on dissociated glucan chains separated by multiple (4-5) solvation shells, in the presence of several novel solvents and solvent mixtures. The solubility of the chains in each solvent was indicated by contacts calculations after the equilibration of the molecular dynamics. It was discovered that pyridine and imidazole acted as the best solvents because their aromatic electronic structure was able to effectively disrupt the inter-sheet interactions among the glucan chains in the axial direction, and because perturbation of the solvent interactions in the presence of glucan chains was minimal.

21 CFR 173.250 - Methyl alcohol residues.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Methyl alcohol residues. 173.250 Section 173.250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Solvents, Lubricants, Release Agents...

Influence of solvent on micellar morphologies of semifluorinated block copolymers.

PubMed

Lee, Min Young; Kim, Sang Jae; Jeong, Yeon Tae; Kim, Joo Hyun; Gal, Yeong-Soon; Lim, Kwon Taek

2009-12-01

The influence of solvents on micellar architectures of block copolymers composed of poly(1H,1H-dihydroperfluorooctyl methacrylate) and poly(ethylene oxide) was investigated. In this study, binary solvents with desired proportions were chosen, which had remarkable influence on the morphology of the resulting micelles. With simple adjusting the composition of the binary solvent of chloroform and trichlorofluoromethane, interesting shapes of micelle-like aggregates, such as core-shell, cylinder, worm-like and inverted micelles were formed with sizes of 15, 70, 30 and 250 nm, respectively. In the case of methanol/water system, core-shell spheres and vesicles were produced by varying the proportion of the contents. The morphologies were also tuned to honeycomb-like and bowl-shaped micelles as well as large planar lamellae with holes in DMF and water binary solvent.

Formation mechanism of 3D macroporous graphene aerogel in alcohol-water media under gamma-ray radiation

NASA Astrophysics Data System (ADS)

Wang, Weikang; Wu, Yihu; Jiang, Zhiwen; Wang, Mozhen; Wu, Qichao; Zhou, Xiao; Ge, Xuewu

2018-01-01

The subtle control on the self-assembly behavior of graphene oxide (GO) nanosheets is one of effective ways for the preparation of high-performance macroscopic graphene-based materials. In this work, detailed characterizations and discussion on the morphological and compositional changes on the solid products in various alcohol-water dispersions of GO under γ-ray radiation were carried out, proving the concurrent hydroxyalkylation and reduction processes of GO nanosheets in the system, which triggered the spontaneous self-assembly of the hydroxyalkylated and reduced GO nanosheets (HA-rGO). The pH and the volume ratio of alcohol to water (ϕa/w) are the key factors to control the self-assembly of the HA-rGO sheets. A free-standing graphene hydrogel (GH) only forms in the strong acid alcohol-water media with an appropriate ϕa/w. After the freeze-drying of the GH, a macroporous graphene aerogel (GA) was obtained, which exhibited a high absorption performance for not only nonpolar molecules (cyclohexane and kerosene), but also most polar molecules (toluene, chloroform, glycol, etc). This work demonstrates a comprehensive self-assembly mechanism of GO nanosheets in an aqueous media under γ-ray radiation and reveals that GA produced from the reduction of GO can be used as potential super-adsorbents for not only waste oil, but also the polar alcohols.

Process optimization of ultrasound-assisted alcoholic-alkaline treatment for granular cold water swelling starches.

PubMed

Zhu, Bo; Liu, Jianli; Gao, Weidong

2017-09-01

This paper reports on the process optimization of ultrasonic assisted alcoholic-alkaline treatment to prepare granular cold water swelling (GCWS) starches. In this work, three statistical approaches such as Plackett-Burman, steepest ascent path analysis and Box-Behnken design were successfully combined to investigate the effects of major treatment process variables including starch concentration, ethanol volume fraction, sodium hydroxide dosage, ultrasonic power and treatment time, and drying operation, that is, vacuum degree and drying time on cold-water solubility. Results revealed that ethanol volume fraction, sodium hydroxide dosage, applied power and ultrasonic treatment time were significant factors that affected the cold-water solubility of GCWS starches. The maximum cold-water solubility was obtained when treated at 400W of applied power for 27.38min. Optimum volume fraction of ethanol and sodium hydroxide dosage were 66.85% and 53.76mL, respectively. The theoretical values (93.87%) and the observed values (93.87%) were in reasonably good agreement and the deviation was less than 1%. Verification and repeated trial results indicated that the ultrasound-assisted alcoholic-alkaline treatment could be successfully used for the preparation of granular cold water swelling starches at room temperatures and had excellent improvement on the cold-water solubility of GCWS starches. Copyright © 2016. Published by Elsevier B.V.

Biodiesel production from ethanolysis of DPO using deep eutectic solvent (DES) based choline chloride - ethylene glycol as co-solvent

NASA Astrophysics Data System (ADS)

Taslim, Indra, Leonardo; Manurung, Renita; Winarta, Agus; Ramadhani, Debbie Aditia

2017-03-01

Biodiesel is usually produced from transesterification using methanol or ethanol as alcohol. However, biodiesel produced using methanol has several disadvantages because methanol is toxic and not entirely bio-based as it is generally produced from petroleum, natural gas and coal. On the other hand, ethanol also has several disadvantages such as lower reactivity in transesterification process and formation of stable emulsion between ester and glycerol. To improve ethanolysis process, deep eutectic solvent (DES) was prepared from choline chloride and ethylene glycol to be used as co-solvent in ethanolysis. Deep eutectic solvent was prepared by mixing choline chloride and ethylene glycol at molar ratio of 1:2, temperature of 80 °C, and stirring speed of 300 rpm for 1 hour. The DES was characterized by its density and viscosity. The ethanolysis of DPO / Degummed Palm Oil was performed at 70 °C, ethanol to oil molar ratio of 9:1, catalyst (potassium hydroxide) concentration of 0.75 wt.% concentration, co-solvent (DES) concentration of 1, 2, 3, 4, 5 and 6 wt.%, stirring speed of 600 rpm, and reaction time of 1 hour. The obtained biodiesel was then characterized by its density, viscosity and ester content. The oil - ethanol phase condition was observed in reaction tube. The oil - ethanol phase with DES tends to form meniscus compared to that without DES. Which implied that oil and ethanol become more slightly miscible, which favours the reaction. Using DES as co-solvent in ethanolysis resulted in an increase in yield and easier purification. The esters properties met the international standards ASTM D6751, with highest yield achieved at 81.72 % with 99.35 % ethyl ester contents at 4% DES concentration.

Remediating pesticide contaminated soils using solvent extraction

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

Sahle-Demessie, E.; Meckes, M.C.; Richardson, T.L.

Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p{prime}-DDT, p,p{prime}-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as solvents over a wide range of operating conditions. It was demonstrated that a six-stage methanol extraction using a solvent-to-soil ratio of 1.6 can decrease pesticide levels in the soil by more than 99% and reduce the volume of material requiring further treatment by 25 times or more. The high solubility of the pesticides in methanol resulted in rapid extraction rates, with the systemmore » reaching quasi-equilibrium state in 30 minutes. The extraction efficiency was influenced by the number of extraction stages, the solvent-to-soil ratio, and the soil moisture content. Various methods were investigated to regenerate and recycle the solvent. Evaporation and solvent stripping are low cost and reliable methods for removing high pesticide concentrations from the solvent. For low concentrations, GAC adsorption may be used. Precipitating and filtering pesticides by adding water to the methanol/pesticide solution was not successful when tested with soil extracts. 26 refs., 10 figs., 6 tabs.« less

Solvent effects and potential of mean force study of the SN2 reaction of CH3+CN‑ in water

NASA Astrophysics Data System (ADS)

Li, Chen; Liu, Peng; Li, Yongfang; Wang, Dunyou

2018-03-01

We used a combined quantum mechanics and molecular mechanics (QM/MM) method to investigate the solvent effects and potential of mean force of the CH3F+CN‑ reaction in water. Comparing to gas phase, the water solution substantially affects the structures of the stationary points along the reaction path. We quantitatively obtained the solvent effects’ contributions to the reaction: 1.7 kcal/mol to the activation barrier and ‑26.0 kcal/mol to the reaction free energy. The potential mean of force calculated with the density functional theory/MM theory has a barrier height at 19.7 kcal/mol, consistent with the experimental result at 23.0 kcal/mol; the calculated reaction free energy at ‑43.5 kcal/mol is also consistent with the one estimated based on the gas-phase data at ‑39.7 kcal/mol. Project supported by the National Natural Science Foundation of China (Grant No. 11774206) and Taishan Scholarship Fund from Shandong Province, China.

Dependence of the enthalpies of formation of glycylglycinate complexes of nickel(II) on the composition of a mixed water-dimethylsulfoxide solvent

NASA Astrophysics Data System (ADS)

Naumov, V. V.; Kovaleva, Yu. A.; Isaeva, V. A.; Usacheva, T. R.; Sharnin, V. A.

2014-06-01

The heat effects of the complexation reactions of nickel(II) with a glycylglycinate ion in a water-dimethylsulfoxide solvent in a range of compositions of 0.00-0.60 molar parts of dimethylsulfoxide (DMSO) (an ionic strength of 0.1 was maintained using sodium perchlorate) were determined by means of calorimetry at 298.15 K. It is established that the exothermicity of complexation reactions rises by the first two steps and falls upon the addition of a third glycylglycinate anion with an increase in the concentration of DMSO. It is shown that the formation of mono- and bis-glycylglycinate complexes of nickel(II) in a water-DMSO solvent is determined mostly by the enthalpic contribution. It is concluded that the formation of tris-ligand complexes is more associated with the entropic contribution.

Lid dynamics of porcine pancreatic lipase in non-aqueous solvents.

PubMed

Haque, Neshatul; Prabhu, N Prakash

2016-10-01

Understanding the dynamics of enzymes in organic solvents has wider implications on their industrial applications. Pancreatic lipases, which show activity in their lid open-state, demonstrate enhanced activity in organic solvents at higher temperatures. However, the lid dynamics of pancreatic lipases in non-aqueous environment is yet to be clearly understood. Dynamics of porcine pancreatic lipase (PPL) in open and closed conformations was followed in ethanol, toluene, and octanol using molecular simulation methods. In silico double mutant D250V and E254L of PPL (PPLmut-Cl) was created and its lid opening dynamics in water and in octanol was analyzed. PPL showed increase in solvent accessible surface area and decrease in packing density as the polarity of the surrounded solvent decreased. Breaking the interactions between D250-Y115, and D250-E254 in PPLmut-Cl directed the lid to attain open-state conformation. Major energy barriers during the lid movement in water and in octanol were identified. Also, the trajectories of lid movement were found to be different in these solvents. Only the double mutant at higher temperature showed lid opening movement suggesting the essential role of the three residues in holding the lid in closed conformation. The lid opening dynamics was faster in octanol than water suggesting that non-polar solvents favor open conformation of the lid. This study identifies important interactions between the lid and the residues in domain 1 which possibly keeps the lid in closed conformation. Also, it explains the rearrangements of residue-residue interactions during lid opening movement in water and in octanol. Copyright © 2016 Elsevier B.V. All rights reserved.

On the inclusion of alkanes into the monolayer of aliphatic alcohols at the water/alkane vapor interface: a quantum chemical approach.

PubMed

Vysotsky, Yuri B; Fomina, Elena S; Belyaeva, Elena A; Fainerman, Valentin B; Vollhardt, Dieter

2013-02-14

In the framework of the quantum chemical semiempirical PM3 method thermodynamic and structural parameters of the formation and clusterization of aliphatic alcohols C(n)H(2n+1)OH (n(OH) = 8-16) at 298 K at the water/alkane vapor C(n)H(2n+2), (n(CH(3)) = 6-16) interface were calculated. The dependencies of enthalpy, entropy and Gibbs' energy of clusterization per one monomer molecule of 2D films on the alkyl chain length of corresponding alcohols and alkanes, the molar fraction of alkanes in the monolayers and the immersion degree of alcohol molecules into the water phase were shown to be linear or stepwise. The threshold of spontaneous clusterization of aliphatic alcohols at the water/alkane vapor interface was 10-11 carbon atoms at 298 K which is in line with experimental data at the air/water interface. It is shown that the presence of alkane vapor does not influence the process of alcohol monolayer formation. The structure of these monolayers is analogous to those obtained at the air/water interface in agreement with experimental data. The inclusion of alkane molecules into the amphiphilic monolayer at the water/alkane vapor interface is possible for amphiphiles with the spontaneous clusterization threshold at the air/water interface (n(s)(0)) of at least 16 methylene units in the alkyl chain, and it does not depend on the molar fraction of alkanes in the corresponding monolayer. The inclusion of alkanes from the vapor phase into the amphiphilic monolayer also requires that the difference between the alkyl chain lengths of alcohols and alkanes is not larger than n(s)(0) - 15 and n(s)(0) - 14 for the 2D film 1 and 2D film 2, respectively.

Nafion®-catalyzed microwave-assisted Ritter reaction: An atom-economic solvent-free synthesis of amides

EPA Science Inventory

An atom-economic solvent-free synthesis of amides by the Ritter reaction of alcohols and nitriles under microwave irradiation is reported. This green protocol is catalyzed by solid supported Nafion®NR50 with improved efficiency and reduced waste production.

Mechanism of transport and distribution of organic solvents in blood

NASA Technical Reports Server (NTRS)

Lam, C. W.; Galen, T. J.; Boyd, J. F.; Pierson, D. L.

1990-01-01

Little is known about the mechanism of transport and distribution of volatile organic compounds in blood. Studies were conducted on five typical organic solvents to investigate how these compounds are transported and distributed in blood. Groups of four to five rats were exposed for 2 hr to 500 ppm of n-hexane, toluene, chloroform, methyl isobutyl ketone (MIBK), or diethyl ether vapor; 94, 66, 90, 51, or 49%, respectively, of these solvents in the blood were found in the red blood cells (RBCs). Very similar results were obtained in vitro when aqueous solutions of these solvents were added to rat blood. In vitro studies were also conducted on human blood with these solvents; 66, 43, 65, 49, or 46%, respectively, of the added solvent was taken up by the RBCs. These results indicate that RBCs from humans and rats exhibited substantial differences in affinity for the three more hydrophobic solvents studied. When solutions of these solvents were added to human plasma and RBC samples, large fractions (51-96%) of the solvents were recovered from ammonium sulfate-precipitated plasma proteins and hemoglobin. Smaller fractions were recovered from plasma water and red cell water. Less than 10% of each of the added solvents in RBC samples was found in the red cell membrane ghosts. These results indicate that RBCs play an important role in the uptake and transport of these solvents. Proteins, chiefly hemoglobin, are the major carriers of these compounds in blood. It can be inferred from the results of the present study that volatile lipophilic organic solvents are probably taken up by the hydrophobic sites of blood proteins.

CO{sub 2}-philic oligomers as novel solvents for CO{sub 2} absorption

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

Miller, Matthew B; Luebke, David R; Enick, Robert M

2010-01-01

Desirable properties for an oligomeric CO{sub 2}-capture solvent in an integrated gasification combined cycle (IGCC) plant include high selectivity for CO{sub 2} over H{sub 2} and water, low viscosity, low vapor pressure, low cost, and minimal environmental, health, and safety impacts. The neat solvent viscosity and solubility of CO{sub 2}, measured via bubble-point loci and presented on a pressure−composition diagram (weight basis), and water miscibility in CO{sub 2}-philic solvents have been determined and compared to results obtained with Selexol, a commercial oligomeric CO{sub 2} solvent. The solvents tested include polyethyleneglycol dimethylether (PEGDME), polypropyleneglycol dimethylether (PPGDME), polypropyleneglycol diacetate (PPGDAc), polybutyleneglycol diacetatemore » (PBGDAc), polytetramethyleneetherglycol diacetate (PTMEGDAc), glyceryl triacetate (GTA), polydimethyl siloxane (PDMS), and perfluorpolyether (PFPE) that has a perfluorinated propyleneglycol monomer unit. Overall, PDMS and PPGDME are the best oligomeric solvents tested and exhibit properties that make them very promising alternatives for the selective absorption of CO{sub 2} from a mixed gas stream, especially if the absorption of water is undesirable.« less

Optimization of instantaneous solvent exchange/surface modification process for ambient synthesis of monolithic silica aerogels.

PubMed

Hwang, Sung-Woo; Kim, Tae-Youn; Hyun, Sang-Hoon

2008-06-01

The instantaneous solvent exchange/surface modification (ISE/SM) process for the ambient synthesis of crack-free silica aerogel monoliths with a high production yield was optimized. Monolithic forms of silica wet gels were obtained from aqueous colloidal silica sols prepared via the ion exchange of sodium silicate solutions. Crack-free silica aerogel monoliths were synthesized via an ISE/SM process using isopropyl alcohol/trimethylchlorosilane as a modification agent and n-hexane as a main solvent, followed by ambient drying. The optimum process conditions of the ISE/SM process were investigated by clarifying the reaction mechanism and phenomena. Most effective ranges of process variables on the ISE/SM stage were determined as 0.2500-0.3567 of TMCS/H2O (pore water) in molar ratio and 15-30 of n-hexane/TMCS in volumetric ratio, with a reaction temperature below 283 K. Crack-free silica aerogel monoliths synthesized via these conditions had a well-developed mesoporous structure and excellent properties (bulk density of 0.12-0.14 g/cm3, specific surface area of 724 m2/g), and a high yield (nearly 80%).

Solvent-dependent gating motions of an extremophilic lipase from Pseudomonas aeruginosa

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

Johnson, Quentin R.; Nellas, Ricky B.; Shen, Tongye

2012-07-25

Understanding how organic solvent-stable proteins can function in anhydrous and often complex solutions is essential for the study of the interaction of protein and molecular immiscible interfaces and the design of efficient industrial enzymes in nonaqueous solvents. Using an extremophilic lipase from Pseudomonas aeruginosa as an example, we investigated the conformational dynamics of an organic solvent-tolerant enzyme in complex solvent milieux. Four 100-ns molecular dynamics simulations of the lipase were performed in solvent systems: water, hexane, and two mixtures of hexane and water, 5% and 95% (w/w) hexane. Our results show a solvent-dependent structural change of the protein, especially inmore » the region that regulates the admission of the substrate. We observed that the lipase is much less flexible in hexane than in aqueous solution or at the immiscible interface. Quantified by the size of the accessible channel, the lipase in water has a closed-gate conformation and no access to the active site, while in the hexane-containing systems, the lipase is at various degrees of open-gate state, with the immiscible interface setup being in the widely open conformation ensembles. Furthermore, the composition of explicit solvents in the access channel showed a significant influence on the conformational dynamics of the protein. Interestingly, the slowest step (bottleneck) of the hexane-induced conformational switch seems to be correlated with the slow dehydration dynamics of the channel.« less

Effects of homeopathic mother tinctures on breath alcohol testing.

PubMed

Boatto, Gianpiero; Trignano, Claudia; Burrai, Lucia; Spanu, Andrea; Nieddu, Maria

2015-01-01

In some countries, it is illegal to drive with any detectable amount of alcohol in blood; in others, the legal limit is 0.5 g/L or lower. Recently, some defendants charged with driving under the influence of alcohol and have claimed that positive breath alcohol test results were due to the ingestion of homeopathic mother tinctures. These preparations are obtained by maceration, digestion, infusion, or decoction of herbal material in hydroalcoholic solvent. A series of tests were conducted to evaluate the alcoholic content of three homeopathic mother tinctures and their ability to produce inaccurate breath alcohol results. Nine of 30 subjects gave positive results (0.11-0.82 g/L) when tests were taken within 1 min after drinking mother tincture. All tests taken at least 15 min after the mother tincture consumption and resulted in alcohol-free readings. An observation period of 15-20 min prior to breath alcohol testing eliminates the possibility of false-positive results. © 2014 American Academy of Forensic Sciences.

Salting-out assisted liquid-liquid extraction for the determination of biogenic amines in fruit juices and alcoholic beverages after derivatization with 1-naphthylisothiocyanate and high performance liquid chromatography.

PubMed

Jain, Archana; Gupta, Manju; Verma, Krishna K

2015-11-27

A new method for determining biogenic amines in fruit juices and alcoholic beverages is described involving reaction of biogenic amines with 1-naphthylisothiocyanate followed by extraction of 1-naphthylthiourea derivatives with water-miscible organic solvent acetonitrile when solvents phase separation occurred using ammonium sulphate, a process called salting-out assisted liquid-liquid extraction. The extract was analyzed by high-performance liquid chromatography with UV detection at 254nm. The new reagent avoided many of the inconveniences as observed with existing derivatizing agents, such as dansyl chloride and benzoyl chloride, in regard to their inselectivity, instability, adverse effect of excess reagent, and necessity to remove excess reagent. The procedure has been optimized with respect to reaction time and temperature, water-miscible extraction solvent, and salt for solvents phase separation. Use of reagent as dispersed phase in aqueous medium produced derivatives in high yield. A linear calibration was obtained between the amount of biogenic amines in range 1-1000μgL(-1) and peak areas of corresponding thioureas formed; the correlation coefficient was 0.9965, and the limit of detection and limit of quantification found were 1.1μgL(-1) and 3.2μgL(-1), respectively. The pre-concentration method gave an average enrichment factor of 94. The application of the method has been demonstrated in the determination of biogenic amines in commercial samples of fruit juices and alcoholic beverages. In spiking experiments to real samples, the average recovery found by the present method was 94.5% that agreed well with 95.8% obtained by established comparison methods. Copyright © 2015 Elsevier B.V. All rights reserved.

TiO2 Processed by pressurized hot solvents as a novel photocatalyst for photocatalytic reduction of carbon dioxide

NASA Astrophysics Data System (ADS)

Reli, Martin; Kobielusz, Marcin; Matějová, Lenka; Daniš, Stanislav; Macyk, Wojciech; Obalová, Lucie; Kuśtrowski, Piotr; Rokicińska, Anna; Kočí, Kamila

2017-01-01

Anatase-brookite TiO2 photocatalysts were prepared by the sol-gel process controlled within reverse micelles and processing by pressurized hot solvents-water/methanol/water (TiO2(M)) and water/ethanol/water (TiO2(E)), as an unconventional alternative to common calcination. The main goal of this work was to prepare anatase-brookite mixtures by processing by two different alcohols (methanol and ethanol) and evaluate the influence of the alcohol on the photocatalytic activity. Prepared photocatalysts were characterized by organic elemental analysis, nitrogen physisorption, XRD, UV-vis, photoelectrochemical and spectroelectrochemical measurements and XPS. The prepared photocatalysts efficiency was tested on the photocatalytic reduction of carbon dioxide and compared with commercial TiO2 Evonik P25. Both prepared nanocomposites were more efficient towards methane production but Evonik P25 was the most efficient towards hydrogen generated through water splitting. The higher performance of anatase-brookite mixture towards methane production can be explained by (i) a higher photocatalytic activity of brookite than rutile; (ii) a large surface area of anatase-brookite composites enabling better carbon dioxide adsorption; (iii) the photoinduced electron transfer from the brookite conduction band to the anatase conduction band. On the other hand, a higher production of hydrogen in the presence of Evonik P25 is caused by a better charge separation in anatase-rutile than anatase-brookite phase compositions. TiO2(M) appeared more active than TiO2(E) in the photocatalytic reduction of carbon dioxide due to a lower density of defects created in the crystal lattice.

Water resistance and thermal properties of polyvinyl alcohol-starch fiber blend film

NASA Astrophysics Data System (ADS)

Salleh, M. S. N.; Nor, N. N. Mohamed; Mohd, N.; Draman, S. F. Syed

2017-02-01

The growing attention of starch fiber (SF) has led to the innovation of Polyvinyl Alcohol-SF (PVA-SF) blends. This blend is regarded as the biodegradable material which aims to reduce the accumulation of synthetic polymer solid waste derived from petroleum. In this study, the thermal blending characterizations of PVA-SF were investigated by differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The water resistance of the blend was also evaluated to study the polarity of the blends. The blend was prepared by plasticizing the polyvinyl alcohol with glycerol and distilled water with the addition of starch fiber. The incorporation of SF to the blends was at 10 wt% to 50 wt% composition. Based on the thermal analysis, PVA-SF blends were suitable for processing at high temperatures, which can be seen by the shifted onset degradation temperature to a higher temperature. This is because cyclic hemiacetals which were provided by SF can act to prevent the thermal attacks. Conversely, increasing the starch fiber proportion to the film blend reduce the endothermic peak amplitude in the DSC thermogram. It was found that PVA-SF blend at the higher composition of SF had the highest water resistance. This may be attributed to the content of fibre in SF which is hydrophilic.

The role of proton shuttling mechanisms in solvent-free and catalyst-free acetalization reactions of imines.

PubMed

Lillo, Victor J; Mansilla, Javier; Saá, José M

2018-06-06

Proton transfer is central to the understanding of chemical processes. More so in addition reactions of the type NuH + E → Nu-EH taking place under solvent-free and catalyst-free conditions. Herein we show that the addition of alcohols or amines (the NuH component) to imine derivatives (the E component), in 1 : 1 ratio, under solvent-free and catalyst-free conditions, are efficient methods to access N,O and N,N-acetal derivatives. In addition, computational studies reveal that they are catalyzed reactions involving two or even three NuH molecules operating in a cooperative manner as H-bonded NuH(NuH)nNuH associates (many body effects) in the transition state through a concerted proton shuttling mechanism (addition of alcohols) or stepwise proton shuttling mechanism (addition of amines), thereby facilitating the key proton transfer step.

Charge-transfer-to-solvent reactions from I{sup −} to water, methanol, and ethanol studied by time-resolved photoelectron spectroscopy of liquids

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

Okuyama, Haruki; Karashima, Shutaro; Suzuki, Toshinori, E-mail: suzuki@kuchem.kyoto-u.ac.jp

The charge-transfer-to-solvent (CTTS) reactions from iodide (I{sup −}) to H{sub 2}O, D{sub 2}O, methanol, and ethanol were studied by time-resolved photoelectron spectroscopy of liquid microjets using a magnetic bottle time-of-flight spectrometer with variable pass energy. Photoexcited iodide dissociates into a weak complex (a contact pair) of a solvated electron and an iodine atom in similar reaction times, 0.3 ps in H{sub 2}O and D{sub 2}O and 0.5 ps in methanol and ethanol, which are much shorter than their dielectric relaxation times. The results indicate that solvated electrons are formed with minimal solvent reorganization in the long-range solvent polarization field createdmore » for I{sup −}. The photoelectron spectra for CTTS in H{sub 2}O and D{sub 2}O—measured with higher accuracy than in our previous study [Y. I. Suzuki et al., Chem. Sci. 2, 1094 (2011)]—indicate that internal conversion yields from the photoexcited I{sup −*} (CTTS) state are less than 10%, while alcohols provide 2–3 times greater yields of internal conversion from I{sup −*}. The overall geminate recombination yields are found to be in the order of H{sub 2}O > D{sub 2}O > methanol > ethanol, which is opposite to the order of the mutual diffusion rates of an iodine atom and a solvated electron. This result is consistent with the transition state theory for an adiabatic outer-sphere electron transfer process, which predicts that the recombination reaction rate has a pre-exponential factor inversely proportional to a longitudinal solvent relaxation time.« less

Hydration of alcohol clusters in 1-propanol-water mixture studied by quasielastic neutron scattering and an interpretation of anomalous excess partial molar volume.

PubMed

Misawa, M; Inamura, Y; Hosaka, D; Yamamuro, O

2006-08-21

Quasielastic neutron scattering measurements have been made for 1-propanol-water mixtures in a range of alcohol concentration from 0.0 to 0.167 in mole fraction at 25 degrees C. Fraction alpha of water molecules hydrated to fractal surface of alcohol clusters in 1-propanol-water mixture was obtained as a function of alcohol concentration. Average hydration number N(ws) of 1-propanol molecule is derived from the value of alpha as a function of alcohol concentration. By extrapolating N(ws) to infinite dilution, we obtain values of 12-13 as hydration number of isolated 1-propanol molecule. A simple interpretation of structural origin of anomalous excess partial molar volume of water is proposed and as a result a simple equation for the excess partial molar volume is deduced in terms of alpha. Calculated values of the excess partial molar volumes of water and 1-propanol and the excess molar volume of the mixture are in good agreement with experimental values.

Method of cross-linking polyvinyl alcohol and other water soluble resins

NASA Technical Reports Server (NTRS)

Phillipp, W. H.; May, C. E.; Hsu, L. C.; Sheibley, D. W. (Inventor)

1980-01-01

A self supporting sheet structure comprising a water soluble, noncrosslinked polymer such as polyvinyl alcohol which is capable of being crosslinked by reaction with hydrogen atom radicals and hydroxyl molecule radicals is contacted with an aqueous solution having a pH of less than 8 and containing a dissolved salt in an amount sufficient to prevent substantial dissolution of the noncrosslinked polymer in the aqueous solution. The aqueous solution is then irradiated with ionizing radiation to form hydrogen atom radicals and hydroxyl molecule radicals and the irradiation is continued for a time sufficient to effect crosslinking of the water soluble polymer to produce a water insoluble polymer sheet structure. The method has particular application in the production of battery separators and electrode envelopes for alkaline batteries.

O2 and Water Migration Pathways between the Solvent and Heme Pockets of Hemoglobin with Open and Closed Conformations of the Distal HisE7.

PubMed

Shadrina, Maria S; Peslherbe, Gilles H; English, Ann M

2015-09-01

Hemoglobin transports O2 by binding the gas at its four hemes. Hydrogen bonding between the distal histidine (HisE7) and heme-bound O2 significantly increases the affinity of human hemoglobin (HbA) for this ligand. HisE7 is also proposed to regulate the release of O2 to the solvent via a transient E7 channel. To reveal the O2 escape routes controlled by HisE7 and to evaluate its role in gating heme access, we compare simulations of O2 diffusion from the distal heme pockets of the T and R states of HbA performed with HisE7 in its open (protonated) and closed (neutral) conformations. Irrespective of HisE7's conformation, we observe the same four or five escape routes leading directly from the α- or β-distal heme pockets to the solvent. Only 21-53% of O2 escapes occur via these routes, with the remainder escaping through routes that encompass multiple internal cavities in HbA. The conformation of the distal HisE7 controls the escape of O2 from the heme by altering the distal pocket architecture in a pH-dependent manner, not by gating the E7 channel. Removal of the HisE7 side chain in the GlyE7 variant exposes the distal pockets to the solvent, and the percentage of O2 escapes to the solvent directly from the α- or β-distal pockets of the mutant increases to 70-88%. In contrast to O2, the dominant water route from the bulk solvent is gated by HisE7 because protonation and opening of this residue dramatically increase the rate of influx of water into the empty distal heme pockets. The occupancy of the distal heme site by a water molecule, which functions as an additional nonprotein barrier to binding of the ligand to the heme, is also controlled by HisE7. Overall, analysis of gas and water diffusion routes in the subunits of HbA and its GlyE7 variant sheds light on the contribution of distal HisE7 in controlling polar and nonpolar ligand movement between the solvent and the hemes.

Viscoelastic stability of resin-composites aged in food-simulating solvents.

PubMed

Marghalani, Hanadi Y; Watts, David C

2013-09-01

To study time-dependent viscoelastic deformation (creep and recovery) of resin-composites, after conditioning in food-simulating solvents, under a compressive stress at 37°C. Five dimethacrylate-based composites: (Spectrum TPH, Premise Body, Tetric Ceram HB, Filtek P60, X-tra fil), and two Ormocers (Experimental Ormocer V 28407, Admira) were studied. Three groups of cylindrical specimens (4mm×6mm) were prepared and then conditioned in 3 solvents: methyl ethyl ketone (MEK), ethanol, and water for 1 month at 37°C. The compressive creep-strain under 35MPa in 37°C water was recorded continuously for 2h and then the unloaded recovery-strain was monitored for another 2h. The data were analyzed by one-way ANOVA and Bonferroni's test. The materials all exhibited classic creep and recovery curves, with most parameters being significantly different (p<0.0001) for each solvent condition. All materials showed lower creep-strain in water than in ethanol or MEK solvents. Maximum creep-strain and permanent-set gave negative linear-regression (r(2)>0.98) with logarithm of the solvent solubility-parameter. The % mean (SD) creep-strain ranged from a minimum of 0.82 (0.01) for the Exp. Ormocer in water to the maximum of 4.19 (0.30) for Admira in MEK. Similar trends were found for permanent-set. The dimethacrylate-based composites behaved as an intermediate group, apart from X-tra fil that had similar stability to the Exp. Ormocer. The viscoelastic stability (low creep and permanent-set) of the Exp. Ormocer, compared to many dimethacrylate-based composites, in food-simulating solvents may be due to its diluent-free formulation. This was closely matched by a highly-filled dimethacrylate material (X-tra fil). Copyright © 2013 Academy of Dental Materials. All rights reserved.

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes.

PubMed

Kürten, Charlotte; Syrén, Per-Olof

2016-01-16

Enzyme catalysis evolved in an aqueous environment. The influence of solvent dynamics on catalysis is, however, currently poorly understood and usually neglected. The study of water dynamics in enzymes and the associated thermodynamical consequences is highly complex and has involved computer simulations, nuclear magnetic resonance (NMR) experiments, and calorimetry. Water tunnels that connect the active site with the surrounding solvent are key to solvent displacement and dynamics. The protocol herein allows for the engineering of these motifs for water transport, which affects specificity, activity and thermodynamics. By providing a biophysical framework founded on theory and experiments, the method presented herein can be used by researchers without previous expertise in computer modeling or biophysical chemistry. The method will advance our understanding of enzyme catalysis on the molecular level by measuring the enthalpic and entropic changes associated with catalysis by enzyme variants with obstructed water tunnels. The protocol can be used for the study of membrane-bound enzymes and other complex systems. This will enhance our understanding of the importance of solvent reorganization in catalysis as well as provide new catalytic strategies in protein design and engineering.

Effect of alcohol on the structure of cytochrome C: FCS and molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Amin, Md. Asif; Halder, Ritaban; Ghosh, Catherine; Jana, Biman; Bhattacharyya, Kankan

2016-12-01

Effect of ethanol on the size and structure of a protein cytochrome C (Cyt C) is investigated using fluorescence correlation spectroscopy (FCS) and molecular dynamics (MD) simulations. For FCS studies, Cyt C is covalently labeled with a fluorescent probe, alexa 488. FCS studies indicate that on addition of ethanol, the size of the protein varies non-monotonically. The size of Cyt C increases (i.e., the protein unfolds) on addition of alcohol (ethanol) up to a mole fraction of 0.2 (44.75% v/v) and decreases at higher alcohol concentration. In order to provide a molecular origin of this structural transition, we explore the conformational free energy landscape of Cyt C as a function of radius of gyration (Rg) at different compositions of water-ethanol binary mixture using MD simulations. Cyt C exhibits a minimum at Rg ˜ 13 Å in bulk water (0% alcohol). Upon increasing ethanol concentration, a second minimum appears in the free energy surface with gradually larger Rg up to χEtOH ˜ 0.2 (44.75% v/v). This suggests gradual unfolding of the protein. At a higher concentration of alcohol (χEtOH > 0.2), the minimum at large Rg vanishes, indicating compaction. Analysis of the contact map and the solvent organization around protein indicates a preferential solvation of the hydrophobic residues by ethanol up to χEtOH = 0.2 (44.75% v/v) and this causes the gradual unfolding of the protein. At high concentration (χEtOH = 0.3 (58% v/v)), due to structural organization in bulk water-ethanol binary mixture, the extent of preferential solvation by ethanol decreases. This causes a structural transition of Cyt C towards a more compact state.

Risk of liver cancer and exposure to organic solvents and gasoline vapors among Finnish workers.

PubMed

Lindbohm, Marja-Liisa; Sallmén, Markku; Kyyrönen, Pentti; Kauppinen, Timo; Pukkala, Eero

2009-06-15

We investigated the association between exposure to various groups of solvents and gasoline vapors and liver cancer. A cohort of economically active Finns born between 1906 and 1945 was followed up during the period 1971-1995. The incident cases of primary liver cancer (n = 2474) were identified in a record linkage with the Finnish Cancer Registry. Occupations from the 1970 census were converted to exposures using a job-exposure matrix. Cumulative exposure was calculated as the product of estimated prevalence, level and duration of exposure, and we used Poisson regression to calculate the relative risks (RR). Among the occupations entailing exposure to organic solvents, an elevated liver cancer incidence was observed in male printers, and varnishers and lacquerers. Among men, the risk was increased in the highest exposure category of aromatic hydrocarbons [RR 1.77, 95% confidence interval (CI) 1.30-2.40], aliphatic/alicyclic hydrocarbons (RR 1.47, 95% CI 0.99-2.18), chlorinated hydrocarbons (RR 2.65, 95% CI 1.38-5.11) and "other solvents" (RR 2.14, 95% CI 1.23-3.71). Among women, the risk was increased for the group "other solvents" that includes mainly alcohols, ketones, esters and glycol ethers (RR 2.73, 95% CI 1.21-6.16). Our finding of an increased risk among workers exposed to chlorinated hydrocarbons is in line with several earlier studies on trichloroethylene. The results also suggest a link between exposure to other types of solvents and the risk of liver cancer. The possibility that alcohol consumption contributes to the observed risks cannot be totally excluded. Copyright 2008 UICC.

Thermodynamics of formation for the 18-crown-6-triglycine molecular complex in water-dimethylsulfoxide solvents

NASA Astrophysics Data System (ADS)

Usacheva, T. R.; Lan, Pham Thi; Sharnin, V. A.

2014-06-01

The effect of a water-dimethylsulfoxide (DMSO) solvent on the formation of a molecular complex of 18-crown-6 (18C6) with triglycine (diglycylglycine, 3Gly) is studied via calorimetric titration. It is found that switching from water to an H2O-DMSO mixture with DMSO mole fraction of 0.30 is accompanied by a monotonic increase in the stability of [3Gly18C6] complex, from log K ∘ = 1.10 to log K ∘ = 2.44, and an increase in the exothermicity of the reaction of its formation, from -5.9 to -16.9 kJ/mol. It is shown that the [3Gly18C6] complex exhibits enthalpy stabilization with negative values of enthalpy and entropy over the investigated range of H2O-DMSO solvents. Analysis of the reagents' solvation characteristics reveals that the increase in the reaction's exothermicity of transfer is due to differences in the solvation of [3Gly18C6] and 18C6 with a small solvation contribution from 3Gly. It is concluded that the change in the Gibbs energy of the reaction 3Glysolv + 18C6solv ↔ [3Gly18C6]solv is due to differences in the change in the solvation state of the complex and the peptide (Δtr G ∘([3Gly18C6])-Δtr G ∘(3Gly)).

Deuterium and oxygen-18 isotope effects on nucleophilic displacement by monomeric water in aprotic solvents

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

Kurz, J.L.; Lee, J.

1980-07-30

The H/sub 2/O/D/sub 2/O rate-constant ratio for nucleophilic attack by water at a methyl carbon (eq 1) is reduced to very near unity when the water is a dilute solute in L/sub 2/O+CH/sub 3/X..-->..L/sub 2/O/sup +/CH/sub 3/+X/sup -/ a dipolar aprotic solvent. This effect was observed for three leaving groups (CH/sub 3/X equals 1-methylthiophenium ion (MeTh/sup +/), methyl perchlorate (MeOCl/sub 3/), and methyl trifluoromethanesulfonate (MeOTf)) and for two aprotic solvents acetonitrile (MeCn), and tetrahydrothiophene 1,1-dioxide (TMSO:'';sulfolane). It was also observed that the corresponding H/sub 2//sup 16/O/H/sub 2//sup 18/O rate-constant ratio is 1.002 +- 0.004 (95% confidence limits) for the reactionmore » of MeTh/sup +/ with dilute H/sub 2/O in TMSO/sub 2/ at 35/sup 0/C. Although alternative explanations exist (vide infra), these observations are consistent with a mechanism in which no significant positive charge is present on the L/sub 2/O oxygen in the rate-determining transition state and thus in which the rate-determining process does not involve (and is not preceded by) any significant covalent-bonding interaction between the nucleophile and the methyl carbon. All reactions were followed by uv spectroscopy in a Cary 16K spectrophotometer.« less

Effects of Beer, Non-Alcoholic Beer and Water Consumption before Exercise on Fluid and Electrolyte Homeostasis in Athletes.

PubMed

Castro-Sepulveda, Mauricio; Johannsen, Neil; Astudillo, Sebastián; Jorquera, Carlos; Álvarez, Cristian; Zbinden-Foncea, Hermann; Ramírez-Campillo, Rodrigo

2016-06-07

Fluid and electrolyte status have a significant impact on physical performance and health. Pre-exercise recommendations cite the possibility of consuming beverages with high amounts of sodium. In this sense, non-alcoholic beer can be considered an effective pre-exercise hydration beverage. This double-blind, randomized study aimed to compare the effect of beer, non-alcoholic beer and water consumption before exercise on fluid and electrolyte homeostasis. Seven male soccer players performed 45 min of treadmill running at 65% of the maximal heart rate, 45 min after ingesting 0.7 L of water (W), beer (AB) or non-alcoholic beer (NAB). Body mass, plasma Na⁺ and K⁺ concentrations and urine specific gravity (USG) were assessed before fluid consumption and after exercise. After exercise, body mass decreased (p < 0.05) in W (-1.1%), AB (-1.0%) and NAB (-1.0%). In the last minutes of exercise, plasma Na⁺ was reduced (p < 0.05) in W (-3.9%) and AB (-3.7%), plasma K⁺ was increased (p < 0.05) in AB (8.5%), and USG was reduced in W (-0.9%) and NAB (-1.0%). Collectively, these results suggest that non-alcoholic beer before exercise could help maintain electrolyte homeostasis during exercise. Alcoholic beer intake reduced plasma Na⁺ and increased plasma K⁺ during exercise, which may negatively affect health and physical performance, and finally, the consumption of water before exercise could induce decreases of Na⁺ in plasma during exercise.

Experimental Limiting Oxygen Concentrations for Nine Organic Solvents at Temperatures and Pressures Relevant to Aerobic Oxidations in the Pharmaceutical Industry

PubMed Central

2015-01-01

Applications of aerobic oxidation methods in pharmaceutical manufacturing are limited in part because mixtures of oxygen gas and organic solvents often create the potential for a flammable atmosphere. To address this issue, limiting oxygen concentration (LOC) values, which define the minimum partial pressure of oxygen that supports a combustible mixture, have been measured for nine commonly used organic solvents at elevated temperatures and pressures. The solvents include acetic acid, N-methylpyrrolidone, dimethyl sulfoxide, tert-amyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, methanol, acetonitrile, and toluene. The data obtained from these studies help define safe operating conditions for the use of oxygen with organic solvents. PMID:26622165

Experimental limiting oxygen concentrations for nine organic solvents at temperatures and pressures relevant to aerobic oxidations in the pharmaceutical industry

DOE PAGES

Osterberg, Paul M.; Niemeier, Jeffry K.; Welch, Christopher J.; ...

2014-12-06

Applications of aerobic oxidation methods in pharmaceutical manufacturing are limited in part because mixtures of oxygen gas and organic solvents often create the potential for a flammable atmosphere. To address this issue, limiting oxygen concentration (LOC) values, which define the minimum partial pressure of oxygen that supports a combustible mixture, have been measured for nine commonly used organic solvents at elevated temperatures and pressures. The solvents include acetic acid, N-methylpyrrolidone, dimethyl sulfoxide, tert-amyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, methanol, acetonitrile, and toluene. Furthermore, the data obtained from these studies help define safe operating conditions for the use of oxygen with organicmore » solvents.« less

Dispersions of Goethite Nanorods in Aprotic Polar Solvents

PubMed Central

Coursault, Delphine; Dozov, Ivan; Nobili, Maurizio; Dupont, Laurent; Chanéac, Corinne

2017-01-01

Colloidal suspensions of anisotropic nanoparticles can spontaneously self-organize in liquid-crystalline phases beyond some concentration threshold. These phases often respond to electric and magnetic fields. At lower concentrations, usual isotropic liquids are observed but they can display very strong Kerr and Cotton-Mouton effects (i.e., field-induced particle orientation). For many examples of these colloidal suspensions, the solvent is water, which hinders most electro-optic applications. Here, for goethite (α-FeOOH) nanorod dispersions, we show that water can be replaced by polar aprotic solvents, such as N-methyl-2-pyrrolidone (NMP) and dimethylsulfoxide (DMSO), without loss of colloidal stability. By polarized-light microscopy, small-angle X-ray scattering and electro-optic measurements, we found that the nematic phase, with its field-response properties, is retained. Moreover, a strong Kerr effect was also observed with isotropic goethite suspensions in these polar aprotic solvents. Furthermore, we found no significant difference in the behavior of both the nematic and isotropic phases between the aqueous and non-aqueous dispersions. Our work shows that goethite nanorod suspensions in polar aprotic solvents, suitable for electro-optic applications, can easily be produced and that they keep all their outstanding properties. It also suggests that this solvent replacement method could be extended to the aqueous colloidal suspensions of other kinds of charged anisotropic nanoparticles. PMID:29039797

Development of a Gas Chromatography/Mass Spectrometry Method for the Analysis of the Solvent Stabilizer 1,4-Dioxane in Drinking Water

EPA Science Inventory

The solvent stabilizer 1,4-dioxane was named to the latest draft Drinking Water Contaminant Candidate List (CCL3) in February 2008 by the United States Environmental Protection Agency (USEPA). To collect occurrence data under the Unregulated Contaminant Monitoring Regulation (UC...

Etoposide-induced blood-brain barrier disruption. Effect of drug compared with that of solvents.

PubMed

Spigelman, M K; Zappulla, R A; Johnson, J; Goldsmith, S J; Malis, L I; Holland, J F

1984-10-01

The intracarotid infusion of the anti-neoplastic compound, etoposide, has been shown to exert a dose-dependent effect on blood-brain barrier (BBB) permeability. Etoposide, however, is formulated in a complex solvent solution containing alcohol, Tween 80, polyethylene glycol 300, and citric acid. To investigate the contribution of the solvent solution to BBB disruption, the authors studied Sprague-Dawley rats after the internal carotid artery infusion of the solvent solution with and without the addition of etoposide. Experiments were performed at four doses of drug and/or solvent. Disruption of the BBB was evaluated qualitatively by the appearance of the systemically administered dye, Evans blue, in the cerebral hemispheres and quantitatively by the ratio of gamma counts of the technetium-labeled chelate of diethylenetriaminepentaacetic acid (99mTc-DTPA) in the ipsilateral:contralateral hemisphere. Significant barrier opening was obtained in all four groups of animals infused with solvent plus etoposide. In the corresponding groups of rats infused with the solvent solution alone, BBB disruption was markedly lower. Only in the group infused with the largest dose of solvent was the hemispheric ratio of 99mTc-DTPA significantly different from saline-infused animals. Each of the groups with solvent plus etoposide had 99mTc-DTPA ratios significantly different from the control group. Intracarotid infusion and subsequent BBB disruption were well tolerated by the animals receiving either solvent alone or solvent and etoposide. Disruption of the BBB secondary to the intracarotid infusion of etoposide is primarily caused by the drug itself and not by the solvent solution.

Dielectric Studies on Binary Mixtures of Diethyl Ether (DEE) in Polar Solvents

NASA Astrophysics Data System (ADS)

Pradhan, S. K.; Dash, S. K.; Swain, M. D.; Swain, B. B.

2011-11-01

Dielectric constant (ɛ) of diethylether (DEE) in binary mixtures with four polar solvents such as n-butanl, i-butanol, t-butanol and tolune has been measured at 455 kHz and at a temperature 303.15 K. The refractive indices were measured at a regulated temperature by Pulfrich refractometer at sodium D-line. The data is used to evaluate mutual correlation factor gab, excess molar polarization and excess free energy of mixing ΔGab by using Winkelmann-Quitzsch equation for binary mixtures to asses the suitability of the polar solvents as modifiers. The trend of variation for these parameters exhibit marked dependence on the nature of alcohols. Diethylether is one of the solvent extractant used for the extraction and separation of zirconium and hafnium in reactor technology. The extractant is blended with appropriate polar modifiers for greater dispersal and more rapid phase disengagement. This facilitates in the elimination of the third organo-aqueous phase containing some of the metal ions. As such the study of molecular interaction among the component molecules has been undertaken in these binary mixtures using the dielectric route. The interaction parameters such as mutual correlation factor gab is found to be less than one in all alcohols, while it is negative in toluene upto 0.7 DEE molefraction and thereafter becoming positive. The nature of variation of the excess miolar polarization ΔP and excess free energy of mixing Gab tends to support the assessment of gab to choose a suitable polar modifier.

Effect of solvents on the enzyme mediated degradation of copolymers

NASA Astrophysics Data System (ADS)

Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar

2015-09-01

The biodegradation of polycaprolactone (PCL), polylactic acid (PLA), polyglycolide (PGA) and their copolymers, poly (lactide-co-glycolide) and poly (D, L-lactide-co-caprolactone) (PLCL) was investigated. The influence of different solvents on the degradation of these polymers at 37 °C in the presence of two different lipases namely Novozym 435 and the free lipase of porcine pancreas was investigated. The rate coefficients for the polymer degradation and enzyme deactivation were determined using continuous distribution kinetics. Among the homopolymers, the degradation of PGA was nearly an order of magnitude lower than that for PCL and PLA. The overall rate coefficients of the copolymers were higher than their respective homopolymers. Thus, PLCL degraded faster than either PCL or PLA. The degradation was highly dependent on the viscosity of the solvent used with the highest degradation observed in acetone. The degradation of the polymers in acetone was nearly twice that observed in dimethyl sulfoxide indicating that the degradation decreases with increase in the solvent viscosity. The degradation of the polymers in water-solvent mixtures indicated an optimal water content of 2.5 wt% of water.

Water-enhanced solvation of organics

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

Lee, Jane H.

1993-07-01

Water-enhanced solvation (WES) was explored for Lewis acid solutes in Lewis base organic solvents, to develop cheap extract regeneration processes. WES for solid solutes was determined from ratios of solubilities of solutes in water-sat. and low-water solvent; both were determined from solid-liquid equilibrium. Vapor-headspace analysis was used to determine solute activity coefficients as function of organic phase water concentration. WES magnitudes of volatile solutes were normalized, set equal to slope of log γ s vs x w/x s curve. From graph shape Δ(log γ s) represents relative change in solute activity coefficient. Solutes investigated by vapor-headspace analysis were acetic acid,more » propionic acid, ethanol, 1,2-propylene glycol, 2,3-butylene glycol. Monocarboxylic acids had largest decrease in activity coefficient with water addition followed by glycols and alcohols. Propionic acid in cyclohexanone showed greatest water-enhancement Δ(log γ acid)/Δ(x w/x acid) = -0.25. In methylcyclohexanone, the decrease of the activity coefficient of propionic acid was -0.19. Activity coefficient of propionic acid in methylcyclohexanone stopped decreasing once the water reached a 2:1 water to acid mole ratio, implying a stoichiometric relation between water, ketone, and acid. Except for 2,3-butanediol, activity coefficients of the solutes studied decreased monotonically with water content. Activity coefficient curves of ethanol, 1,2-propanediol and 2,3-butanediol did not level off at large water/solute mole ratio. Solutes investigated by solid-liquid equilibrium were citric acid, gallic acid, phenol, xylenols, 2-naphthol. Saturation concentration of citric acid in anhydrous butyl acetate increased from 0.0009 to 0.087 mol/L after 1.3 % (g/g) water co-dissolved into organic phase. Effect of water-enhanced solvation for citric acid is very large but very small for phenol and its derivatives.« less

Exceptional ion rejection ability of directional solvent for non-membrane desalination

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

Rish, Daniel; Department of Civil Engineering, University of Notre Dame, Notre Dame, Indiana 46556; Luo, Shirui

2014-01-13

The recently demonstrated directional solvent extraction (DSE) is promising for very low temperature, membrane-free water desalination. In this paper, we combine atomistic simulations and experimental validation to demonstrate that the currently used directional solvent, decanoic acid, can reject all major salt ions in seawater, with very high rejection rates. The salinities of the DSE recovered water show that ion rejection rates are ∼98%–99%—similar to those of the best reverse osmosis membranes. Our test also shows that the DSE process can desalt seawater to produce fresh water that meets drinking water standards.

FT-IR spectroscopy combined with DFT calculation to explore solvent effects of vinyl acetate

NASA Astrophysics Data System (ADS)

Chen, Yi; Zhang, Hui; Liu, Qing

The infrared vibration frequencies of vinyl acetate (VAc) in 18 different solvents were theoretically computed at Density Function Theory (DFT) B3LYP/6-311G* level based on Polarizable Continuum Model (PCM) and experimentally recorded by FT-IR spectroscopy. The solvent-induced long-range bulk electrostatic solvation free energies of VAc (ΔGelec) were calculated by the SMD model. The Cdbnd O stretching vibration frequencies of VAc were utilized as a measure of the chemical reactivities of the Cdbnd C group in VAc. The calculated and experimental Cdbnd O stretching vibration frequencies of VAc (νcal(Cdbnd O) and νexp(Cdbnd O)) were correlated with empirical solvent parameters including the KBM equation, the Swain equation and the linear solvation energy relationships (LSER). Through ab initio calculation, assignments of the two Cdbnd O absorption bands of VAc in alcohol solvents were achieved. The PCM, SMD and ab initio calculation offered supporting evidence to explain the FT-IR experimental observations from differing aspects.

Aqueous or solvent based surface modification: The influence of the combination solvent - organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

NASA Astrophysics Data System (ADS)

Roevens, Annelore; Van Dijck, Jeroen G.; Geldof, Davy; Blockhuys, Frank; Prelot, Benedicte; Zajac, Jerzy; Meynen, Vera

2017-09-01

To alter the versatility of interactions at its surface, TiO2 is modified with organophosphonic acids (PA). A thorough understanding of the role of all synthesis conditions is necessary to achieve controlled functionalization. This study reports on the effect of using water, toluene and their mixtures when performing the modification of TiO2 with PA. Sorption and calorimetry measurements of surface interactions with various probing species clearly indicate that, by grafting PA in water, clear differences appear in the distribution of organic groups on the surface. Also the functional group of the PA determines the impact of using water as solvent. Modification in toluene results in a higher modification degree for propylphosphonic acid (3PA), as the solvent-solute interaction may hinder the grafting with phenylphosphonic acid (PhPA) in toluene. Water is preferred as solvent for PhPA modification as stabilizing π-OH interactions enhance surface grafting overcoming the competitive interaction of water at the surface as observed with 3PA. By using water in toluene mixtures for the functionalization of TiO2 with 3PA, the degree of functionalization is higher than when only water or toluene is used. Furthermore, adding small amounts of water leads to the formation of titanium propylphosphonates, next to surface grafting.

Fire extinguishing tests -80 with methyl alcohol gasoline (in MIXED)

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

Holmstedt, G.; Ryderman, A.; Carlsson, B.

1980-01-01

Large scale tests and laboratory experiments were carried out for estimating the extinguishing effectiveness of three alcohol resistant aqueous film forming foams (AFFF), two alcohol resistant fluoroprotein foams and two detergent foams in various poolfires: gasoline, isopropyl alcohol, acetone, methyl-ethyl ketone, methyl alcohol and M15 (a gasoline, methyl alcohol, isobutene mixture). The scaling down of large scale tests for developing a reliable laboratory method was especially examined. The tests were performed with semidirect foam application, in pools of 50, 11, 4, 0.6, and 0.25 sq m. Burning time, temperature distribution in the liquid, and thermal radiation were determined. An M15more » fire can be extinguished with a detergent foam, but it is impossible to extinguish fires in polar solvents, such as methyl alcohol, acetone, and isopropyl alcohol with detergent foams, AFFF give the best results, and performances with small pools can hardly be correlated with results from large scale fires.« less