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Sample records for acetonitrile propylene carbonate

  1. Factors influencing high voltage performance of coconut char derived carbon based electrical double layer capacitor made using acetonitrile and propylene carbonate based electrolytes

    NASA Astrophysics Data System (ADS)

    Hu, Changzheng; Qu, Weiguo; Rajagopalan, Ramakrishnan; Randall, Clive

    2014-12-01

    Symmetric EDLCs made using high purity carbon electrodes derived from coconut char were tested using 1 M Tetraethylammonium hexafluorophosphate dissolved in two different solvents namely acetonitrile and propylene carbonate. The cell voltage of the capacitor made using propylene carbonate can be extended to 3.5 V and it exhibited good cycling and thermal stability upto 70 °C while the voltage was limited to below 3.0 V in acetonitrile. XPS analysis of the positive and negative electrodes of EDLCs post cycling showed that the primary degradation products were related to ring opening reactions in propylene carbonate based electrolytes while water played a key role in degradation of acetonitrile based EDLCs.

  2. Greening pharmaceutical applications of liquid chromatography through using propylene carbonate-ethanol mixtures instead of acetonitrile as organic modifier in the mobile phases.

    PubMed

    Tache, Florentin; Udrescu, Stefan; Albu, Florin; Micăle, Florina; Medvedovici, Andrei

    2013-03-01

    Substitution of acetonitrile (ACN) as organic modifier in mobile phases for liquid chromatography by mixtures of propylene carbonate (PC) and ethanol (EtOH) may be considered a greener approach for pharmaceutical applications. Such a replacement is achievable without any major compromise in terms of elution order, chromatographic retention, efficiency and peak symmetry. This has been equally demonstrated for reverse phase (RP), ion pair formation (IP) and hydrophilic interaction liquid chromatography (HILIC) separation modes. The impact on the sensitivity induced by the replacement between these organic solvents is discussed for UV-vis and mass spectrometric detection. A comparison between Van Deemter plots obtained under elution conditions based on ACN and PC/EtOH is presented. The alternative elution modes were also compared in terms of thermodynamic parameters, such as standard enthalpy (ΔH⁰) and entropic contributions to the partition between the mobile and the stationary phases, for some model compounds. Van't Hoff plots demonstrated that differences between the thermodynamic parameters are minor when shifting from ACN/water to PC/EtOH/water elution on an octadecyl chemically modified silicagel stationary phase. As long as large volume injection (LVI) of diluents non-miscible with the mobile phase is a recently developed topic having a high potential of greening the sample preparation procedures through elimination of the solvent evaporation stage, this feature was also assessed in the case of ACN replacement by PC/EtOH. PMID:23277155

  3. ENVIRONMENTAL PROFILE FOR PROPYLENE CARBONATE

    EPA Science Inventory

    The overall goal of this research is to document the life cycle environmental impacts of propylene carbonate (PC) to assist DoD in assessing the life cycle environmental implications of PC and PC-based formulations as viable alternative materials, products, and techniques to pain...

  4. Acetonitrile

    Integrated Risk Information System (IRIS)

    Acetonitrile ; CASRN 75 - 05 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  5. The Electrodeposition of Silver from Supercritical Carbon Dioxide/Acetonitrile

    PubMed Central

    Bartlett, Philip N; Perdjon-Abel, Magdalena; Cook, David; Reid, Gillian; Levason, William; Cheng, Fei; Zhang, Wenjian; George, Michael W; Ke, Jie; Beanland, Richard; Sloan, Jeremy

    2014-01-01

    Cyclic voltammetry of silver coordination complexes in acetonitrile and in a single-phase supercritical carbon dioxide/acetonitrile (scCO2/CH3CN) system is reported. Five silver precursors are investigated: (1,5-cyclooctadiene)(hexafluoroacetylacetonato) silver(I) [Ag(hfac)(COD)], (hexafluoroacetylacetonato)(triphenylphosphine) silver(I) [Ag(hfac)(PPh3)], (perfluorooctanoato)bis(triphenylphosphine) silver(I) [Ag(CF3(CF2)6CO2)(PPh3)2], tetrakis(triphenylphosphine) silver(I) tetrafluoroborate [Ag(PPh3)4][BF4] and tetrakis(acetonitrile) silver(I) tetrafluoroborate [Ag(CH3CN)4][BF4]. Of these, [Ag(CH3CN)4][BF4] is found to be the most suitable for electrodeposition of silver from scCO2/CH3CN.

  6. BF3-promoted electrochemical properties of quinoxaline in propylene carbonate

    DOE PAGESBeta

    Carino, Emily V.; Diesendruck, Charles E.; Moore, Jeffrey S.; Curtiss, Larry A.; Assary, Rajeev S.; Brushett, Fikile R.

    2015-02-04

    Electrochemical and density functional studies demonstrate that coordination of electrolyte constituents to quinoxalines modulates their electrochemical properties. Quinoxalines are shown to be electrochemically inactive in most electrolytes in propylene carbonate, yet the predicted reduction potential is shown to match computational estimates in acetonitrile. We find that in the presence of LiBF4 and trace water, an adduct is formed between quinoxaline and the Lewis acid BF3, which then displays electrochemical activity at 1–1.5 V higher than prior observations of quinoxaline electrochemistry in non-aqueous media. Direct synthesis and testing of a bis-BF3 quinoxaline complex further validates the assignment of the electrochemically activemore » species, presenting up to a ~26-fold improvement in charging capacity, demonstrating the advantages of this adduct over unmodified quinoxaline in LiBF4-based electrolyte. The use of Lewis acids to effectively “turn on” the electrochemical activity of organic molecules may lead to the development of new active material classes for energy storage applications.« less

  7. Ordered mesoporous carbon catalyst for dehydrogenation of propane to propylene.

    PubMed

    Liu, Lei; Deng, Qing-Fang; Agula, Bao; Zhao, Xu; Ren, Tie-Zhen; Yuan, Zhong-Yong

    2011-08-01

    Metal-free ordered mesoporous carbons were demonstrated to be robust catalysts for direct dehydrogenation of propane to propylene, in the absence of any auxiliary steam, exhibiting high activity and selectivity, as well as long catalytic stability, in comparison with nanostructured carbons. PMID:21687889

  8. Permeability and partitioning of ferrocene ethylene oxide and propylene oxide oligomers into electropolymerized films from acetonitrile and polyether solutions

    SciTech Connect

    Pyati, R.; Murray, R.W. )

    1994-10-27

    We report the first electrochemically-based measurements of the rates of small polymer permeation into another polymer. The small polymer permeants are ferrocene ethylene oxide oligomers containing 2, 7, and 16 units and a propylene oxide oligomer containing 3 units. Their permeation into ultrathin microelectrode-supported films of the metal complex polymer poly[Ru(vbpy)[sub 3

  9. Dynamics in propylene carbonate and propylene carbonate containing LiPF6

    NASA Astrophysics Data System (ADS)

    Fontanella, John J.; Wintersgill, Mary C.; Immel, Jeffrey J.

    1999-03-01

    Electrical conductivity and differential scanning calorimetry studies (DSC) have been carried out on 1 M LiPF6 in propylene carbonate (PC) from 187 to 296 K. The electrical conductivity data are analyzed in terms of Vogel-Tammann-Fulcher (VTF), Williams-Landel-Ferry (WLF), and Bendler-Shlesinger (BENSH) formalisms. In addition, literature data for viscosity and relaxation times for PC (not containing salt) are analyzed using the same formalisms. Large, systematic variations are found in both the VTF and WLF fitting parameters with temperature interval. The large variation of the parameters with temperature demonstrates the failure of both formalisms and shows that care must be taken when utilizing the VTF/WLF parameters to draw conclusions concerning the behavior of systems. One conclusion which can be reached is that the VTF results indicate a significant difference between the molecular motions in PC and PC-containing LiPF6. Another is that the WLF parameter C1 is about 11 for low temperature data, referenced to the DSC glass transition temperature, Tg, which shows that for PC and PC-based liquids the value of all three dynamical quantities at Tg is about 11 decades smaller than the value predicted for very high temperatures. Finally, all data are found to be better fit by the BENSH equation.

  10. Bubble-free electrokinetic flow with propylene carbonate.

    PubMed

    Sritharan, Deepa; Chen, Abraham Simpson; Aluthgama, Prabhath; Naved, Bilal; Smela, Elisabeth

    2015-10-01

    For electroosmotic pumping, a large direct-current (DC) electric field (10+ V/cm) is applied across a liquid, typically an aqueous electrolyte. At these high voltages, water undergoes electrolysis to form hydrogen and oxygen, generating bubbles that can block the electrodes, cause pressure fluctuations, and lead to pump failure. The requirement to manage these gases constrains system designs. This article presents an alternative polar liquid for DC electrokinetic pumping, propylene carbonate (PC), which remains free of bubbles up to at least 10 kV/cm. This offers the opportunity to create electrokinetic devices in closed configurations, which we demonstrate with a fully sealed microfluidic hydraulic actuator. Furthermore, the electroosmotic velocity of PC is similar to that of water in PDMS microchannels. Thus, water could be substituted by PC in existing electroosmotic pumps. PMID:26178406

  11. BF3-promoted electrochemical properties of quinoxaline in propylene carbonate

    SciTech Connect

    Carino, Emily V.; Diesendruck, Charles E.; Moore, Jeffrey S.; Curtiss, Larry A.; Assary, Rajeev S.; Brushett, Fikile R.

    2015-02-04

    Electrochemical and density functional studies demonstrate that coordination of electrolyte constituents to quinoxalines modulates their electrochemical properties. Quinoxalines are shown to be electrochemically inactive in most electrolytes in propylene carbonate, yet the predicted reduction potential is shown to match computational estimates in acetonitrile. We find that in the presence of LiBF4 and trace water, an adduct is formed between quinoxaline and the Lewis acid BF3, which then displays electrochemical activity at 1–1.5 V higher than prior observations of quinoxaline electrochemistry in non-aqueous media. Direct synthesis and testing of a bis-BF3 quinoxaline complex further validates the assignment of the electrochemically active species, presenting up to a ~26-fold improvement in charging capacity, demonstrating the advantages of this adduct over unmodified quinoxaline in LiBF4-based electrolyte. The use of Lewis acids to effectively “turn on” the electrochemical activity of organic molecules may lead to the development of new active material classes for energy storage applications.

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

    SciTech Connect

    Chaudhari, Mangesh I.; You, Xinli; Pratt, Lawrence R.; Rempe, Susan B.

    2015-11-24

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

  13. Vinyl ethers containing a cyclic carbonate group. I. Synthesis of 3-(/omega/-vinyloxyalkoxy)propylene 1,2-carbonates

    SciTech Connect

    Nedolya, N.A.; Tatarova, T.F.; Vyalykh, E.P.; Trofimov, B.A.

    1989-01-10

    In order to synthesize 3-(/omega/-vinyloxyalkoxy)propylene 1,2-carbonates the authors studied the reaction of /omega/-vinyloxyalkoxymethyloxiranes with carbon dioxide at 140-180/degree/C, catalyzed by a tertiary amine (triethylamine). The main results from this reaction are described. The effect of the reaction conditions (solvent, concentration of catalyst, ratio of reagents, state of aggregation of the carbon dioxide, process temperature and time) on the result were studied for the case of 2-vinyloxyethoxymethyloxirane. The reaction leads with high yields to functional vinyl ethers of a new type - 3-(/omega/-vinyloxyalkoxy)propylene 1,2-carbonates.

  14. Dielectric constants of binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate from molecular dynamics simulation: comparison between non-polarizable and polarizable force fields

    NASA Astrophysics Data System (ADS)

    Lee, Sanghun; Park, Sung Soo

    2013-01-01

    Using non-polarizable and polarizable molecular dynamics simulations, binary mixtures of propylene carbonate + dimethyl carbonate and propylene carbonate + ethylene carbonate with various compositions were investigated. The polarizable model produces more reasonable estimation of dielectric constants than the non-polarizable model; however, combining the electronic continuum model with the non-polarizable MD improves the comparison between the two models. Fair agreement was found between the results from these simulations and available experimental data. In addition, for a better understanding of the mixing behaviour, the excess dielectric constants over the entire composition were calculated. By comparison of the two mixtures in various mole fractions, distinctive mixing behaviours of propylene carbonate + dimethyl carbonate (poorly symmetric mixture) and propylene carbonate + ethylene carbonate (highly symmetric mixture) were observed.

  15. EVALUATION OF PROPYLENE CARBONATE IN AIR LOGISTICS CENTER (ALC) DEPAINTING OPERATIONS

    EPA Science Inventory

    This report summarizes a two-phase, laboratory-scale screening study that evaluated solvent blends containing propylene carbonate (PC) as a potential replacement for methyl ethyl ketone (MEK) in aircraft radome depainting operations. he study was conducted at Oklahoma City Air Lo...

  16. Enhanced dielectric breakdown performances of propylene carbonate modified by nano-particles under microsecond pulses

    NASA Astrophysics Data System (ADS)

    Hou, Yanpan; Zhang, Jiande; Zhang, Zicheng

    2016-06-01

    Propylene carbonate shows appealing prospects as an energy storage medium in the compact pulsed power sources because of its large permittivity, high dielectric strength, and broad operating temperature range. In this paper, TiO2 nano-particles coated with γ-aminopropyltriethoxylsilane coupling agent are homogeneously dispersed into propylene carbonate and these nano-fluids (NFs) exhibit substantially larger breakdown voltages than those of pure propylene carbonate. It is proposed that interfaces between nano-fillers and propylene carbonate matrix may provide myriad trap sites for charge carriers. The charge carriers can be easily captured at the interfaces between NFs and the electrode, resulting in an increased barrier height and suppressed charge carriers injection, and in the bulk of NFs, the charge carriers' mean free path can be greatly shortened by the scattering effect. As a result, in order for charge carriers acquiring enough energy to generate a region of low density (the bubble) and initiate breakdown in NFs, much higher applied field is needed.

  17. EVALUATION OF PROPYLENE CARBONATE IN AIR LOGISTICS CENTER (ALC) DEPAINTING OPERATIONS

    EPA Science Inventory

    This report summarizes a two-phase, laboratory-scale screening study that evaluated solvent blends containing propylene carbonate (PC) as a potential replacement for methyl ethyl ketone (MEK) in aircraft radome depainting operations. The study was conducted at Oklahoma City Air L...

  18. Effect of the electrode material on the breakdown voltage and space charge distribution of propylene carbonate under impulse voltage

    NASA Astrophysics Data System (ADS)

    Yang, Qing; Jin, Yang; Sima, Wenxia; Liu, Mengna

    2016-04-01

    This paper reports three types of electrode materials (copper, aluminum, and stainless steel) that are used to measure the impulse breakdown voltage of propylene carbonate. The breakdown voltage of propylene carbonate with these electrode materials is different and is in decreasing order of stainless steel, copper, and aluminum. To explore how the electrode material affects the insulating properties of the liquid dielectric, the electric field distribution and space charge distribution of propylene carbonate under impulse voltage with the three electrode materials are measured on the basis of a Kerr electro-optic test. The space charge injection ability is highest for aluminum, followed by copper, and then the stainless steel electrodes. Furthermore, the electric field distortion rate decreased in the order of the aluminum, copper, and then the stainless steel electrode. This paper explains that the difference in the electric field distortion rate between the three electrode materials led to the difference in the impulse breakdown voltage of propylene carbonate.

  19. Homogeneous liquid-liquid solvent extraction. [Propylene carbonate-water system

    SciTech Connect

    Ting, C.S.; Williams, E.T.; Finston, H.L.

    1980-01-01

    This investigation was undertaken to extend the technique of homogeneous liquid-liquid solvent extraction into propylene carbonate. The mutual solubilities of propylene carbonate in water and vice-versa are shown in the phase diagram. The extraction of a variety of monodentate and bidentate ligand complexes with Fe(III) as a function of ligand concentration and pH were investigated. The monodentate ligands studied include, thiocyanate, chloride, bromide, benzoate, and bathophenanthrolines. The bidentate ligands studied include the various ..beta..-diketones, 8-quinolinol, and also cupferron which was studied under normal conditions, i.e., not under conditions of homogeneous extraction. The homogeneous extraction proved effective for a variety of chelate complexes and ion association complexes of iron giving, in all cases, very rapid extraction as compared with the slow rate of conventional extraction methods.

  20. Hydrogenolysis of 5-carbon sugars, sugar alcohols, and methods of making propylene glycol

    DOEpatents

    Werpy, Todd A [West Richland, WA; Zacher, Alan H [Kennewick, WA

    2006-05-02

    Methods and compositions for reactions of hydrogen over a Re-containing catalyst with compositions containing a 5-carbon sugar, sugar alcohol, or lactic acid are described. It has been surprisingly discovered that reaction with hydrogen over a Re-containing multimetallic catalyst resulted in superior conversion and selectivity to desired products such as propylene glycol. A process for the synthesis of PG from lactate or lactic acid is also described.

  1. FILM FORMATION ON LITHIUM IN PROPYLENE CARBONATE SOLUTIONS UNDER OPEN CIRCUIT CONDITIONS

    SciTech Connect

    Geronov, Y.; Schwager, F.; Muller, R.H.

    1980-06-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO{sub 4} and LiAsF{sub 6} at open circuit has been investigated by electrochemical pulse measurements. The results are consistent with the fastformation of a compact thin layer resulting from the reaction with residual water. This layer acts as a solid ionicconductor. Slow corrosion or decomposition processes produce a thicker porous overlayer.

  2. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open circuit conditions

    SciTech Connect

    Geronov, Y.; Schwager, F.; Muller, R.H.

    1981-04-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements and other techniques. The results are consistent with the fast formation of a compact thin layer of Li/sub 2/O by reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion processes produce a thicker porous overlayer.

  3. Combined carbon and nitrogen removal from acetonitrile using algal-bacterial bioreactors.

    PubMed

    Muñoz, Raul; Jacinto, Marco; Guieysse, Benoit; Mattiasson, Bo

    2005-06-01

    When compared with Chlorella vulgaris, Scenedesmus obliquus and Selenastrum capricornutum, C. sorokiniana presented the highest tolerance to acetonitrile and the highest O(2) production capacity. It also supported the fastest acetonitrile biodegradation when mixed with a suitable acetonitrile-degrading bacterial consortium. Consequently, this microalga was tested in symbiosis with the bacterial culture for the continuous biodegradation of acetonitrile at 2 g l(-1) in a stirred tank photobioreactor and in a column photobioreactor under continuous illumination (250 microE m(-2) s(-1)). Acetonitrile removal rates of up to 2.3 g l(-1) day(-1) and 1.9 g l(-1) day(-1) were achieved in the column photobioreactor and the stirred-tank photobioreactor, respectively, when operated at the shortest retention times tested (0.4 days, 0.6 days, respectively). In addition, when the stirred-tank photobioreactor was operated with a retention time of 3.5 days, the microbial culture was capable of assimilating up to 71% and nitrifying up to 12% of the NH(4) (+) theoretically released through the biodegradation of acetonitrile, thus reducing the need for subsequent nitrogen removal. This study suggests that complete removal of N-organics can be combined with a significant removal of nitrogen by using algal-bacterial systems and that further residual biomass digestion could pay-back part of the operation costs of the treatment plant. PMID:15666149

  4. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    SciTech Connect

    Afanasiev, Pavel

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoS{sub x} (x≈4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoS{sub x} under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS{sub 2} materials with very high pore volume and specific surface area, up to 0.45 cm{sup 3}/g and 190 m{sup 2}/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoS{sub x} particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS{sub 2} with very high porosity and surface area.

  5. Effective, selective coupling of propylene oxide and carbon dioxide to poly(propylene carbonate) using (salen)CrN3 catalysts.

    PubMed

    Darensbourg, Donald J; Phelps, Andrea L

    2005-06-27

    The copolymerization of propylene oxide and CO2 has been investigated employing Cr(salen)N3 complexes as catalysts. Unfortunately the reaction could not be studied in real time via in situ IR spectroscopy, thereby obtaining detailed kinetic data, because of the copolymer limited solubility in most solvents. Investigations employing batch reactor runs concentrating on varying the cocatalyst, the equivalents of cocatalyst, and the steric and electronic structure of the catalyst through modification of the salen ligand were undertaken. It was discovered that the optimal catalyst for copolymer selectivity vs the monomeric propylene carbonate was one that contained a salen ligand with an electron-withdrawing phenylene backbone and electron-donating tert-butyl groups in the phenolate rings. This catalyst was used to investigate the effect of altering the nature of the cocatalyst and its concentration, the three cocatalysts being tricyclohexylphosphine (PCy3), PPN+ N3(-), and PPN+ Cl-, where PPN+ is the large very weakly interacting bis(triphenylphosphoramylidene)ammonium cation. By utilization of more or less than 1 equiv of PCy3 as cocatalyst, the yield of polymer was reduced. On the other hand, the PPN+ salts showed the best activity when 0.5 equiv was employed, and produced only cyclic when using over 1 equiv. PMID:15962970

  6. Models of Ion Solvation Thermodynamics in Ethylene Carbonate and Propylene Carbonate.

    PubMed

    Arslanargin, Ayse; Powers, August; Beck, Thomas L; Rick, Steven W

    2016-03-01

    Ethylene carbonate (EC) and propylene carbonate (PC) are organic solvents used extensively in energy storage applications such as lithium-ion batteries and supercapacitors. Using statistical mechanical theory and computer simulations, this paper compares and contrasts the thermodynamics of ion solvation in EC and PC with the behavior observed in water. The EC and PC solvents are modeled with the AMBER (GAFF) force field. Ion-solvent interactions are treated with two point-charge models: one using an existing Lennard-Jones ion parameter set optimized for solvation in water, and the other based on high-level quantum calculations on ion-solvent dimers and fitting to a Buckingham-type potential form. The second model produces a coordination number for the Li(+) ion in closer agreement with experiment. Neither model yields consistently accurate solvation thermodynamic quantities (free energies, enthalpies, and entropies), however. The simulations and thermodynamic analysis illustrate key physical aspects of the solvation; the studies also point to necessary modifications of these simple models. In particular, the calculations show that polarization and associated dispersion forces are important and that well-optimized polarizable or quantum models are likely required to accurately reproduce condensed-phase properties of ions in these technologically important solvents. PMID:26292974

  7. Supercharging with m-nitrobenzyl alcohol and propylene carbonate: forming highly charged ions with extended, near-linear conformations.

    PubMed

    Going, Catherine C; Williams, Evan R

    2015-04-01

    The effectiveness of the supercharging reagents m-nitrobenzyl alcohol (m-NBA) and propylene carbonate at producing highly charged protein ions in electrospray ionization is compared. Addition of 5% m-NBA or 15% propylene carbonate increases the average charge of three proteins by ∼21% or ∼23%, respectively, when these ions are formed from denaturing solutions (water/methanol/acetic acid). These results indicate that both reagents are nearly equally effective at supercharging when used at their optimum concentrations. A narrowing of the charge state distribution occurs with both reagents, although this effect is greater for propylene carbonate. Focusing the ion signal into fewer charge states has the advantage of improving sensitivity. The maximum charge state of ubiquitin formed with propylene carbonate is 21+, four charges higher than previously reported. Up to nearly 30% of all residues in a protein can be charged, and the collisional cross sections of the most highly charged ions of both ubiquitin and cytochrome c formed with these supercharging reagents were measured for the first time and found to be similar to those calculated for theoretical highly extended, linear or near-linear conformations. Under native supercharging conditions, m-NBA is significantly more effective at producing high charge states than propylene carbonate. PMID:25719488

  8. Fitting the excess wing in the dielectric α-relaxation of propylene carbonate

    NASA Astrophysics Data System (ADS)

    Hilfer, R.

    2002-03-01

    A novel fitting function for the complex frequency-dependent dielectric susceptibility is introduced and compared against other fitting functions for experimental broadband dielectric loss spectra of propylene carbonate taken from Schneider et al (Schneider U, Lunkenheimer P, Brand R and Loidl A 1999 Phys. Rev. E 59 6924). The fitting function contains a single stretching exponent similar to the familiar Cole-Davidson or Kohlrausch stretched exponential fits. It is compared to these traditional fits as well as to the Havriliak-Negami susceptibility and a susceptibility for a two-step Debye relaxation. The results for the novel fit are found to give superior agreement.

  9. Electrochemical photovoltaic cells based on n-GaAs in propylene carbonate

    NASA Astrophysics Data System (ADS)

    Langmuir, M. E.; Hoenig, P.; Rauh, R. D.

    1981-11-01

    Electrochemical photovoltaic cells (EPC's) have been characterized based on n-GaAs and propylene carbonate electrolytes. Photovoltages are limited to about 0.7V due to electrode corrosion and lack of specific adsorption by the redox systems studied. Polarization of photo and counterelectrodes, resulting from low redox solubilities and electrolyte conductivities, are responsible for lower fill factors and short-circuit photocurrents for nonaqueous, compared to aqueous, EPC's. Potentially, these losses can be offset by higher voltages and long-term stabilities, particularly if specifically adsorbing redox couples can be found.

  10. Bonding of copper surface in ambient air using propylene carbonate as passivation layer

    NASA Astrophysics Data System (ADS)

    Zhu, Zhiyuan; Yu, Min; Phillips, Oluwadamilola; Liu, Lisha; Jin, Yufeng

    2015-07-01

    Bonding of a copper surface in a nonvacuum environment has been studied for the purpose of reducing manufacturing costs. Cu-Cu bonding in ambient air is demonstrated by using propylene carbonate (PPC) as a passivation layer. The decomposition of the PPC passivation layer during bonding would protect the copper surface from oxidation by providing a shielding gas atmosphere between the copper surface and the air. Further, the PPC passivation layer would also overcome the degradation of copper surface during storage in the atmosphere.

  11. Behaviour of highly crystalline graphites in lithium-ion cells with propylene carbonate containing electrolytes

    NASA Astrophysics Data System (ADS)

    Buqa, H.; Würsig, A.; Goers, D.; Hardwick, L. J.; Holzapfel, M.; Novák, P.; Krumeich, F.; Spahr, M. E.

    Several TIMREX ® synthetic and natural graphite negative electrode materials with different particle size distributions were tested with regard to their compatibility with propylene carbonate used as electrolyte component in lithium-ion cells. The first lithium insertion properties of these graphite materials were characterised in electrochemical lithium half-cells containing 1 M LiPF 6 in ethylene carbonate/propylene carbonate as electrolyte system. Post mortem scanning electron microscopy was applied to study the exfoliation process observed for some of these graphite materials especially with coarser particle sizes. X-ray diffraction, Raman spectroscopy and nitrogen gas adsorption were used to characterise and correlate the material bulk and surface properties of the graphite materials with their electrochemical performance. Differential electrochemical mass spectrometry was applied to study the passivation process of the graphite material surface during the first electrochemical reduction. Non-exfoliating graphite materials indicate the formation of an efficient solid electrolyte interphase, which seems to be kinetically controlled by intrinsic properties of the graphite material bulk and surface.

  12. Ring-opening graft polymerization of propylene carbonate onto xylan in an ionic liquid.

    PubMed

    Zhang, Xueqin; Chen, Mingjie; Liu, Chuanfu; Zhang, Aiping; Sun, Runcang

    2015-01-01

    The amidine organocatalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is an effective nucleophilic catalyst. Biocomposites with tuneable properties were successfully synthesized by ring-opening graft polymerization (ROGP) of propylene carbonate (PC) onto xylan using DBU as a catalyst in the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The effects of reaction temperature, reaction time and the molar ratio of PC to anhydroxylose units (AXU) in xylan were investigated. The physico-chemical properties of xylan-graft-poly(propylene carbonate) (xylan-g-PPC) copolymers were characterised by FT-IR, NMR, TGA/DTG, AFM and tensile analysis. The FT-IR and NMR results indicated the successful attachment of PPC onto xylan. TGA/DTG suggested the increased thermal stability of xylan after the attachment of PPC side chains. AFM analysis revealed details about the molecular aggregation of xylan-g-PPC films. The results also showed that with the increased DS of xylan-g-PPC copolymers, the tensile strength and Young's modulus of the films decreased, while the elongation at break increased. PMID:25853319

  13. Dielectric spectroscopy and ultrasonic study of propylene carbonate under ultra-high pressures

    NASA Astrophysics Data System (ADS)

    Kondrin, M. V.; Gromnitskaya, E. L.; Pronin, A. A.; Lyapin, A. G.; Brazhkin, V. V.; Volkov, A. A.

    2012-08-01

    We present the high pressure dielectric spectroscopy (up to 4.2 GPa) and ultrasonic study (up to 1.7 GPa) of liquid and glassy propylene carbonate (PC). Both of the methods provide complementary pictures of the glass transition in PC under pressure. No other relaxation processes except α-relaxation have been found in the studied pressure interval. The propylene carbonate liquid is a glassformer where simple relaxation and the absence of β-relaxation are registered in the record-breaking ranges of pressures and densities. The equation of state of liquid PC was extended up to 1 GPa from ultrasonic measurements of bulk modulus and is in good accordance with the previous equations developed from volumetric data. We measured the bulk and shear moduli and Poisson's ratio of glassy PC up to 1.7 GPa. Many relaxation and elastic properties of PC can be qualitatively described by the soft-sphere or Lennard-Jones model. However, for the quantitative description of entire set of the experimental data, these models are insufficient. Moreover, the Poisson coefficient value for glassy PC indicates a significant contribution of non-central forces to the intermolecular potential. The well-known correlation between Poisson's ratio and fragility index (obtained from dielectric relaxation) is confirmed for PC at ambient pressure, but it is violated with pressure increase. This indicates that different features of the potential energy landscape are responsible for the evolution of dielectric response and elasticity with pressure increase.

  14. Carbon-hydrogen vs. carbon-carbon bond cleavage of 1,2-diarylethane radical cations in acetonitrile-water

    SciTech Connect

    Camaioni, D.M.; Franz, J.A.

    1984-05-04

    Radical cations of 1,2-diarylethanes and 1-phenyl-2-arylethanes (Ar = phenyl, p-tolyl, p-anisyl) were generated in acidic 70% acetonitrile-water by Cu/sup 2 +/-catalyzed peroxydisulfate oxidation. The radical cations fragment mainly by loss of benzylic protons (C-H cleavage) rather than by alkyl C-C bond cleavage. The 1,2-diarylethanol products undergo further selective oxidation to aryl aldehydes and arylmethanols via rapid equilibration of diarylethane and diarylethanol radical cations. The radical cation of 2,3-dimethyl-2,3-diphenylbutane fragments efficiently by C-C cleavage, forming cumyl radical and cumyl cation. Oxidations of bibenzyl-bicumyl mixtures show selective oxidation of bicumyl dependent on total substrate concentration, providing evidence of equilibrating radical cations and showing that bicumyl fragments faster than bibenzyl loses protons. The effects of reaction conditions and substrate structure on reactivity are discussed.

  15. Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N,N-Dimethylformamide

    SciTech Connect

    Pegis, Michael L.; Roberts, John A.; Wasylenko, Derek J.; Mader, Elizabeth A.; Appel, Aaron M.; Mayer, James M.

    2015-12-21

    A variety of energy processes utilize the electrochemical interconversions of dioxygen and water, the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Reported here are the first estimates of the equilibrium reduction potential of the O2 + 4e– + 4H+ 2H2O couple in organic solvents. The values are +1.21 V in acetonitrile (MeCN) and +0.60 V in dimethylformamide (DMF), each versus the ferrocenium/ferrocene couple (Fc+/0) in the respective solvent (as are all the potentials reported here). The potentials have been determined using a thermochemical cycle that combines the free energy for transferring water from aqueous solution to organic solvent, -0.43 kcal mol-1 for MeCN and -1.47 kcal mol-1 for DMF, and the potential of the H+/H2 couple, –0.028 V in MeCN and –0.662 V in DMF. The H+/H2 couple in DMF has been directly measured electrochemically, using the previously reported procedure for the MeCN value. The thermochemical approach used for the O2/H2O couple can also be extended to the CO2/CO and CO2/CH4 couples to give values of -0.12 V and +0.15 V in MeCN, and -0.73 V and -0.48 V in DMF. Extensions to other reduction potentials are discussed. Additionally, the free energy for transfer of protons from water to organic solvent is roughly estimated as +14 kcal mol-1 for acetonitrile and +0.6 kcal mol-1 for dimethylformamide. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

  16. Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N,N-Dimethylformamide.

    PubMed

    Pegis, Michael L; Roberts, John A S; Wasylenko, Derek J; Mader, Elizabeth A; Appel, Aaron M; Mayer, James M

    2015-12-21

    A variety of next-generation energy processes utilize the electrochemical interconversions of dioxygen and water as the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Reported here are the first estimates of the standard reduction potential of the O2 + 4e(-) + 4H(+) ⇋ 2H2O couple in organic solvents. The values are +1.21 V in acetonitrile (MeCN) and +0.60 V in N,N-dimethylformamide (DMF), each versus the ferrocenium/ferrocene couple (Fc(+/0)) in the respective solvent (as are all of the potentials reported here). The potentials have been determined using a thermochemical cycle that combines the free energy for transferring water from aqueous solution to organic solvent, -0.43 kcal mol(-1) for MeCN and -1.47 kcal mol(-1) for DMF, and the potential of the H(+)/H2 couple, - 0.028 V in MeCN and -0.662 V in DMF. The H(+)/H2 couple in DMF has been directly measured electrochemically using the previously reported procedure for the MeCN value. The thermochemical approach used for the O2/H2O couple has been extended to the CO2/CO and CO2/CH4 couples to give values of -0.12 and +0.15 V in MeCN and -0.73 and -0.48 V in DMF, respectively. Extensions to other reduction potentials are discussed. Additionally, the free energy for transfer of protons from water to organic solvent is estimated as +14 kcal mol(-1) for acetonitrile and +0.6 kcal mol(-1) for DMF. PMID:26640971

  17. Effect of electrolyte water content on the anodic passivation of lithium in IM LiC104-propylene carbonate

    NASA Astrophysics Data System (ADS)

    James, S. D.; Nagao, A. R.

    1982-06-01

    This work deals with the effect of aqueous contamination on the anode passivation of Li in 1M LiC10 4-propylene carbonate. Passivation occurs more readily with increasing electrolyte water content. Preliminary evidence suggests that anodic passivation may be due to anodic enrichment and eventual precipitation of LiC10 4 in the superficial anolyte layer.

  18. Ionic conductivity and dielectric permittivity of PEO-LiClO{sub 4} solid polymer electrolyte plasticized with propylene carbonate

    SciTech Connect

    Das, S.; Ghosh, A.

    2015-02-15

    We have studied ionic conductivity and dielectric permittivity of PEO-LiClO{sub 4} solid polymer electrolyte plasticized with propylene carbonate. Differential scanning calorimetry and X-ray diffraction studies confirm minimum volume fraction of crystalline phase for the polymer electrolyte with 40 wt. % propylene carbonate. The ionic conductivity exhibits a maximum for the same composition. The temperature dependence of the ionic conductivity has been well interpreted using Vogel-Tamman-Fulcher equation. Ion-ion interactions in the polymer electrolytes have been studied using Raman spectra and the concentrations of free ions, ion-pairs and ion-aggregates have been determined. The ionic conductivity increases due to the increase of free ions with the increase of propylene carbonate content. But for higher content of propylene carbonate, the ionic conductivity decreases due to the increase of concentrations of ion-pairs and ion-aggregates. To get further insights into the ion dynamics, the experimental data for the complex dielectric permittivity have been studied using Havriliak–Negami function. The variation of relaxation time with temperature obtained from this formalism follows Vogel-Tamman-Fulcher equation similar to the ionic conductivity.

  19. Picosecond Pulse Radiolysis of Propylene Carbonate as a Solute in Water and as a Solvent.

    PubMed

    Marignier, Jean-Louis; Torche, Fayçal; Le Caër, Sophie; Mostafavi, Mehran; Belloni, Jacqueline

    2016-03-10

    The ester propylene carbonate (PC) is a solvent with a high static dielectric constant where the charges generated by ionizing radiation are expected to be long-lived at room temperature. Time-resolved optical absorption spectroscopy after picosecond electron pulses reveals the formation of a UV band, within less than two nanoseconds, that is assigned to the radical anion PC(-•), arising from a fast attachment reaction of electrons onto PC. Assignment and reactivity of PC(-•) in neat solvent and solutions are discussed in relation with data obtained in solutions of PC in water under reducing or oxidizing conditions and in solutions in PC of aromatic scavengers with various reduction potentials. The fate of the electrons and the ionization yield in PC are compared with those of other solvents. PMID:26840402

  20. Solvation of the fluorine containing anions and their lithium salts in propylene carbonate and dimethoxyethane.

    PubMed

    Chaban, Vitaly

    2015-07-01

    Electrolyte solutions based on the propylene carbonate (PC)-dimethoxyethane (DME) mixtures are of significant importance and urgency due to emergence of lithium-ion batteries. Solvation and coordination of the lithium cation in these systems have been recently attended in detail. However, analogous information concerning anions (tetrafluoroborate, hexafluorophosphate) is still missed. This work reports PM7-MD simulations (electronic-structure level of description) to include finite-temperature effects on the anion solvation regularities in the PC-DME mixture. The reported result evidences that the anions appear weakly solvated. This observation is linked to the absence of suitable coordination sites in the solvent molecules. In the concentrated electrolyte solutions, both BF4(-) and PF6(-) prefer to exist as neutral ion pairs (LiBF4, LiPF6). PMID:26067106

  1. Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

    PubMed Central

    Yang, Zhi-Yong; Moure, Vivian R.; Dean, Dennis R.; Seefeldt, Lance C.

    2012-01-01

    A doubly substituted form of the nitrogenase MoFe protein (α-70Val→Ala, α-195His→Gln) has the capacity to catalyze the reduction of carbon dioxide (CO2) to yield methane (CH4). Under optimized conditions, 1 nmol of the substituted MoFe protein catalyzes the formation of 21 nmol of CH4 within 20 min. The catalytic rate depends on the partial pressure of CO2 (or concentration of HCO3−) and the electron flux through nitrogenase. The doubly substituted MoFe protein also has the capacity to catalyze the unprecedented formation of propylene (H2C = CH-CH3) through the reductive coupling of CO2 and acetylene (HC≡CH). In light of these observations, we suggest that an emerging understanding of the mechanistic features of nitrogenase could be relevant to the design of synthetic catalysts for CO2 sequestration and formation of olefins. PMID:23150564

  2. Shear and dielectric responses of propylene carbonate, tripropylene glycol, and a mixture of two secondary amides

    NASA Astrophysics Data System (ADS)

    Gainaru, Catalin; Hecksher, Tina; Olsen, Niels Boye; Böhmer, Roland; Dyre, Jeppe C.

    2012-08-01

    Propylene carbonate and a mixture of two secondary amides, N-methylformamide and N-ethylacetamide, are investigated by means of broadband dielectric and mechanical shear spectroscopy. The similarities between the rheological and the dielectric responses of these liquids and of the previously investigated tripropylene glycol are discussed within a simple approach that employs an electrical circuit for describing the frequency-dependent behavior of viscous materials. The circuit is equivalent to the Gemant-DiMarzio-Bishop model, but allows for a negative capacitive element. The circuit can be used to calculate the dielectric from the mechanical response and vice versa. Using a single parameter for a given system, good agreement between model calculations and experimental data is achieved for the entire relaxation spectra, including secondary relaxations and the Debye-like dielectric peak in the secondary amides. In addition, the predictions of the shoving model are confirmed for the investigated liquids.

  3. Biodegradable poly(propylene carbonate)/montmorillonite nanocomposites prepared by direct melt intercalation

    SciTech Connect

    Xu, J.; Li, R.K.Y. . E-mail: RKYLi@cityu.edu.hk; Meng, Y.Z. . E-mail: stdpmeng@zsu.edu.cn; Mai, Y-.W.

    2006-02-02

    Intercalation-exfoliated nanocomposites derived from poly(propylene carbonate) (PPC) and organo-modified montmorillonite (OMMT) were prepared by direct melt blending in an internal mixer. The nano-scale dispersion of the OMMT layers within the PPC matrix was verified using wide angle X-ray scattering and transmission electron microscopy technologies. Static mechanical properties were determined by using a tensile tester. The PPC/OMMT nanocomposites with lower OMMT content showed an increase in thermal decomposition temperature when compared with both pure PPC and the composites prepared from un-modified MMT. Dynamic mechanical analysis indicated that nano-scale OMMT dispersed well within PPC matrix and therefore enhanced the storage modulus of the composites.

  4. (Salen)tin complexes: syntheses, characterization, crystal structures, and catalytic activity in the formation of propylene carbonate from CO(2) and propylene oxide.

    PubMed

    Jing, Huanwang; Edulji, Smita K; Gibbs, Julianne M; Stern, Charlotte L; Zhou, Hongying; Nguyen, SonBinh T

    2004-07-12

    A series of (salen)tin(II) and (salen)tin(IV) complexes was synthesized. The (salen)tin(IV) complexes, (salen)SnX(2) (X = Br and I), were prepared in good yields via the direct oxidation reaction of (salen)tin(II) complexes with Br(2) or I(2). (Salen)SnX(2) successfully underwent the anion-exchange reaction with AgOTf (OTf = trifluoromethanesulfonate) to form (salen)Sn(OTf)(2) and (salen)Sn(X)(OTf) (X = Br). The (salen)Sn(OTf)(2) complex was easily converted to any of the dihalide (salen)SnX(2) compounds using halide salts. All complexes were fully characterized by (1)H NMR spectroscopy, mass spectrometry, and elemental analysis, while some were characterized by (13)C, (19)F, and (119)Sn NMR spectroscopy. Several crystal structures of (salen)tin(II) and (salen)tin(IV) were also determined. Finally, both (salen)tin(II) and (salen)tin(IV) complexes were shown to efficiently catalyze the formation of propylene carbonate from propylene oxide and CO(2). Of the series, (3,3',5,5'-Br(4)-salen)SnBr(2), 3i, was found to be the most effective catalyst (TOF = 524 h(-)(1)). PMID:15236545

  5. Low-temperature growth of nitrogen-doped carbon nanofibers by acetonitrile catalytic CVD using Ni-based catalysts

    NASA Astrophysics Data System (ADS)

    Iwasaki, Tomohiro; Makino, Yuri; Fukukawa, Makoto; Nakamura, Hideya; Watano, Satoru

    2016-06-01

    To synthesize nitrogen-doped carbon nanofibers (N-CNFs) at high growth rates and low temperatures less than 673 K, nickel species (metallic nickel and nickel oxide) supported on alumina particles were used as the catalysts for an acetonitrile catalytic chemical vapor deposition (CVD) process. The nickel:alumina mass ratio in the catalysts was fixed at 0.05:1. The catalyst precursors were prepared from various nickel salts (nitrate, chloride, sulfate, acetate, and lactate) and then calcined at 1073 K for 1 h in oxidative (air), reductive (hydrogen-containing argon), or inert (pure argon) atmospheres to activate the nickel-based catalysts. The effects of precursors and calcination atmosphere on the catalyst activity at low temperatures were studied. We found that the catalysts derived from nickel nitrate had relatively small crystallite sizes of nickel species and provided N-CNFs at high growth rates of 57 ± 4 g-CNF/g-Ni/h at 673 K in the CVD process using 10 vol% hydrogen-containing argon as the carrier gas of acetonitrile vapor, which were approximately 4 times larger than that of a conventional CVD process. The obtained results reveal that nitrate ions in the catalyst precursor and hydrogen in the carrier gas can contribute effectively to the activation of catalysts in low-temperature CVD. The fiber diameter and nitrogen content of N-CNFs synthesized at high growth rates were several tens of nanometers and 3.5 ± 0.3 at.%, respectively. Our catalysts and CVD process may lead to cost reductions in the production of N-CNFs.

  6. Potentiometric chemical sensors from lignin-poly(propylene oxide) copolymers doped by carbon nanotubes.

    PubMed

    Rudnitskaya, Alisa; Evtuguin, Dmitry V; Costa, Luis C; Graça, M Pedro F; Fernandes, António J S; Correia, M Rosario P; Gomes, M Teresa S R; Oliveira, J A B P

    2013-01-21

    Hardwood and softwood lignins obtained from industrial sulphite and kraft and laboratory oxygen-organosolv pulping processes were employed in co-polymerization with tolylene 2,4-diisocyanate terminated poly(propylene glycol). The obtained lignin-based polyurethanes were doped with 0.72 w/w% of multiwall carbon nanotubes (MWCNTs) with the aim of increasing their electrical conductivity to the levels suitable for sensor applications. Effects of the polymer doping with MWCNTs were assessed using electrical impedance (EIS) and UV-Resonance Raman (UV-RR) spectroscopy. Potentiometric sensors were prepared by drop casting of liquid polymer on the surface of carbon glass or platinum electrodes. Lignin-based sensors displayed a very low or no sensitivity to all alkali, alkali-earth and transition metal cations ions except Cr(VI) at pH 2. Response to Cr(VI) values of 39, 50 and 53 mV pX(-1) for the sensors based on kraft, organosolv and lignosulphonate lignins, respectively, were observed. Redox sensitivity values close to the theoretical values of 20 and 21 mV pX(-1) for organosolv and lignosulphonate based sensors respectively were detected in the Cr(III)/Cr(VI) solutions while a very low response was observed in the solutions containing Fe(CN)(6)(3-/4-). Conducting composite lignin-based polyurethanes doped with MWCNTs were suggested as being promising materials for Cr(VI)-sensitive potentiometric sensors. PMID:23162814

  7. Role of PF6- in the radiolytical and electrochemical degradation of propylene carbonate solutions

    NASA Astrophysics Data System (ADS)

    Ortiz, Daniel; Jimenez Gordon, Isabel; Legand, Solène; Dauvois, Vincent; Baltaze, Jean-Pierre; Marignier, Jean-Louis; Martin, Jean-Frédéric; Belloni, Jacqueline; Mostafavi, Mehran; Le Caër, Sophie

    2016-09-01

    The behavior under irradiation of neat propylene carbonate (PC), a co-solvent usually used in Li-ion batteries (LIB), and also of Li salt solutions is investigated. The decomposition of neat PC is studied using radiolysis in the pulse and steady state regime and is assigned to the ultrafast formation, in the reducing channel, of the radical anion PCrad - by electron attachment, followed by the ring cleavage, leading to CO. In the oxidative channel, the PC(sbnd H)rad radical is formed, generating CO2. The CO2 and CO yields are both close to the ionization yield of PC. The CO2 and CO productions in LiClO4, LiBF4 and LiN(CF3)2(SO2)2 solutions are similar as in neat PC. In contrast, in LiPF6/PC a strong impact on PC degradation is measured with a doubling of the CO2 yield due to the high reactivity of the electron towards PF6- observed in the picosecond range. A small number of oxide phosphine molecules are detected among the various products of the irradiated solutions, suggesting that most of them, observed in carbonate mixtures used in LIBs, arise from linear rather than from cyclical molecules. The similarity between the degradation by radiolysis or electrolysis highlights the interest of radiolysis as an accelerated aging method.

  8. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open-circuit conditions

    SciTech Connect

    Geronov, Y.; Schwager, F.; Muller, R.H.

    1981-11-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements. The results are consistent with the fast formation of a compact thin layer resulting from the reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion or decomposition processes produce a thicker porous overlayer.

  9. Vivid Manifestation of Nonergodicity in Glassy Propylene Carbonate at High Pressures.

    PubMed

    Danilov, Igor V; Gromnitskaya, Elena L; Brazhkin, Vadim V

    2016-08-01

    As glasses are nonergodic systems, their properties should depend not only on external macroparameters, such as P and T, but also on the time of observation and thermobaric history. In this work, comparative ultrasonic studies of two groups of molecular propylene carbonate glasses obtained by quenching from a liquid at pressures of 0.1 and 1 GPa have been performed. Although the difference in the densities of the different groups of glasses is small (3-5%), they have significantly different elastic properties: the difference in the respective bulk moduli is 10-20%, and the difference in the respective shear moduli is 35-40% (!). This is due to the "closure of nanopores" in the glass obtained at 1 GPa. The pressure and temperature derivatives of the elastic moduli for these groups of glasses are also noticeably different. The glass-transition temperatures of glasses from different groups differ by 3-4 K. The character of absorption of ultrasound waves near the glass-transition temperature also differs for different groups of glasses. The differences in the behaviors of these groups of glasses disappear gradually above the glass-transition temperature, in the region of a liquid phase. Glasses with a wide diversity of physical properties can be obtained using various paths on the (T,P) diagram. PMID:27399845

  10. Surface modification of poly(propylene carbonate) by oxygen ion implantation

    NASA Astrophysics Data System (ADS)

    Zhang, Jizhong; Kang, Jiachen; Hu, Ping; Meng, Qingli

    2007-04-01

    Poly(propylene carbonate) (PPC) was implanted by oxygen ion with energy of 40 keV. The influence of experimental parameters was investigated by varying ion fluence from 1 × 10 12 to 1 × 10 15 ions/cm 2. XPS, SEM, surface roughness, wettability, hardness, and modulus were employed to investigate structure and properties of the as-implanted PPC samples. Eight chemical groups, i.e., carbon, C sbnd H, C sbnd O sbnd C, C sbnd O, O sbnd C sbnd O, C dbnd O, ?, and ? groups were observed on surfaces of the as-implanted samples. The species and relative intensities of the chemical groups changed with increasing ion fluence. SEM images displayed that irradiation damage was related strongly with ion fluence. Both surface-recovering and shrunken behavior were observed on surface of the PPC sample implanted with fluence of 1 × 10 15 ions/cm 2. As increasing ion fluence, the surface roughness of the as-implanted PPC samples increased firstly, reached the maximum value of 159 nm, and finally decreased down the minimum value. The water droplet contact angle of the as-implanted PPC samples changed gradually with fluence, and reached the minimum value of 70° with fluence of 1 × 10 15 ions/cm 2. The hardness and modulus of the as-implanted PPC samples increased with increasing ion fluence, and reached their corresponding maximum values with fluence of 1 × 10 15 ions/cm 2. The experimental results revealed that oxygen ion fluence closely affected surface chemical group, morphology, surface roughness, wettability, and mechanical properties of the as-implanted PPC samples.

  11. Interfacial characteristics of propylene carbonate and validation of simulation models for electrochemical applications

    NASA Astrophysics Data System (ADS)

    You, Xinli

    Supercapacitors have occupy an indispensable role in today's energy storage systems due to their high power density and long life. The introduction of car- bon nanotube (CNT) forests as electrode offers the possibility of nano-scale design and high capacitance. We have performed molecular dynamics simulations on a CNT forest-based electrochemical double-layer capacitor (EDLC) and a widely used electrolyte solution (tetra-ethylammonium tetra-fluoroborate in propylene carbonate, TEABF4 /PC). We compare corresponding primitive model and atomically detailed model of TEABF4 /P, emphasizing the significance of ion clustering in electrolytes. The molecular dynamic simulation results suggests that the arrangement of closest neigh- bors leads to the formation of cation-anion chains or rings. Fuoss's discussion of ion-pairing model provides the approximation for a primitive model of 1-1 electrolyte is not broadly satisfactory for both primitive and atomically detailed cases. A more general Poisson statistical assumption is shown to be satisfactory when coordina- tion numbers are low, as is likely to be the case when ion-pairing initiates. We examined the Poisson-based model over a range of concentrations for both models of TEABF4 /P, and the atomically detailed model results identified solvent-separated nearest-neighbor ion-pairs. Large surface areas plays an essential role in nanomaterial properties, which calls for an accurate description of interfaces through modeling. We studied propylene carbonate, a widely used solvent in EDLC systems. PC wets graphite with a contact angle of 31°. The MD simulation model reproduced this contact angle after reduction 40% of the strength of graphite-C atom Lennard-Jones interactions with the solvent. The critical temperature of PC was accurately evaluated by extrapolating the PC liquid-vapor surface tensions. PC molecules tend to lie flat on the PC liquid-vapor surface, and project the propyl carbon toward the vapor phase. Liquid PC

  12. Determining water content in activated carbon for double-layer capacitor electrodes

    NASA Astrophysics Data System (ADS)

    Egashira, Minato; Izumi, Takuma; Yoshimoto, Nobuko; Morita, Masayuki

    2016-09-01

    Karl-Fisher titration is used to estimate water contents in activated carbon and the distribution of impurity-level water in an activated carbon-solvent system. Normalization of the water content of activated carbon is attempted using vacuum drying after immersion in water was controlled. Although vacuum drying at 473 K and 24 h can remove large amounts of water, a substantial amount of water remains in the activated carbon. The water release to propylene carbonate is less than that to acetonitrile. The degradation of capacitor cell capacitance for activated carbon with some amount of water differs according to the electrolyte solvent type: acetonitrile promotes greater degradation than propylene carbonate does.

  13. Combined Quantum Chemical/Raman Spectroscopic Analyses of Li+ Cation Solvation: Cyclic Carbonate Solvents - Ethylene Carbonate and Propylene Earbonate

    SciTech Connect

    Allen, Joshua L.; Borodin, Oleg; Seo, D. M.; Henderson, Wesley A.

    2014-12-01

    Combined computational/Raman spectroscopic analyses of ethylene carbonate (EC) and propylene carbonate (PC) solvation interactions with lithium salts are reported. It is proposed that previously reported Raman analyses of (EC)n-LiX mixtures have utilized faulty assumptions. In the present studies, density functional theory (DFT) calculations have provided corrections in terms of both the scaling factors for the solvent's Raman band intensity variations and information about band overlap. By accounting for these factors, the solvation numbers obtained from two different EC solvent bands are in excellent agreement with one another. The same analysis for PC, however, was found to be quite challenging. Commercially available PC is a racemic mixture of (S)- and (R)-PC isomers. Based upon the quantum chemistry calculations, each of these solvent isomers may exist as multiple conformers due to a low energy barrier for ring inversion, making deconvolution of the Raman bands daunting and inherently prone to significant error. Thus, Raman spectroscopy is able to accurately determine the extent of the EC...Li+ cation solvation interactions using the provided methodology, but a similar analysis of PC...Li+ cation solvation results in a significant underestimation of the actual solvation numbers.

  14. Ultrafast Decay of the Solvated Electron in a Neat Polar Solvent: The Unusual Case of Propylene Carbonate.

    PubMed

    Le Caër, Sophie; Ortiz, Daniel; Marignier, Jean-Louis; Schmidhammer, Uli; Belloni, Jacqueline; Mostafavi, Mehran

    2016-01-01

    The behavior of carbonates is critical for a detailed understanding of aging phenomena in Li-ion batteries. Here we study the first reaction stages of propylene carbonate (PC), a cyclical carbonate, by picosecond pulse radiolysis. An absorption band with a maximum around 1360 nm is observed at 20 ps after the electron pulse and is shifted to 1310 nm after 50 ps. This band presents the features of a solvated electron absorption band, the solvation lasting up to 50 ps. Surprisingly, in this polar solvent, the solvated electron follows an ultrafast decay and disappears with a half time of 360 ps. This is attributed to the formation of a radical anion PC(-•). The yield of the solvated electron is low, suggesting that the radical anions are mainly directly produced from presolvated electrons. These results demonstrate that the initial electron transfers mechanisms are strongly different in linear compared with cyclical carbonates. PMID:26706441

  15. Catalytic Oxidation of Propylene, Toluene, Carbon Monoxide, and Carbon Black over Au/CeO2 Solids: Comparing the Impregnation and the Deposition-Precipitation Methods

    PubMed Central

    Aboukaïs, Antoine; El-Ayadi, Houda; Skaf, Mira; Labaki, Madona; Cousin, Renaud; Abi-Aad, Edmond

    2013-01-01

    Au/CeO2 solids were prepared by two methods: deposition-precipitation (DP) and impregnation (Imp). The prepared solids were calcined under air at 400°C. Both types of catalysts have been tested in the total oxidation of propylene, toluene, carbon monoxide, and carbon black. Au/CeO2-DP solids were the most reactive owing to the high number of gold nanoparticles and Au+ species and the low concentration of Cl− ions present on its surface compared to those observed in Au/CeO2-Imp solids. PMID:24198730

  16. Dipolar Self-Assembling in Mixtures of Propylene Carbonate and Dimethyl Sulfoxide as Revealed by the Orientational Entropy.

    PubMed

    Płowaś, Iwona; Świergiel, Jolanta; Jadżyn, Jan

    2016-08-18

    This article presents the results of static dielectric studies performed on mixtures of two strongly polar liquids important from a technological point of view: propylene carbonate (PC) and dimethyl sulfoxide (DMSO). The dielectric data were analyzed in terms of the molar orientational entropy increment induced by the probing electric field. It was found that the two polar liquids in the neat state reveal quite different molecular organization in terms of dipole-dipole self-assembling: PC exhibits a dipolar coupling of the head-to-tail type, whereas in DMSO one observes extreme restriction of dipolar association in any form. In PC + DMSO mixtures, the disintegration of the dipolar ensembles of PC molecules takes place and the progress of that process is strictly proportional to the concentration of DMSO. The static permittivity of mixtures of such differently self-organized liquids exhibits a positive deviation from the additive rule and the deviation develops symmetrically within the concentration scale. PMID:27458791

  17. Surface Nanobubbles in Nonaqueous Media: Looking for Nanobubbles in DMSO, Formamide, Propylene Carbonate, Ethylammonium Nitrate, and Propylammonium Nitrate.

    PubMed

    An, Hongjie; Liu, Guangming; Atkin, Rob; Craig, Vincent S J

    2015-07-28

    Surface nanobubbles produced by supersaturation during the exchange of ethanol for water are routinely observed on hydrophobic surfaces, are stable for days, and have contact angles that are very much greater than observed macroscopically. Here, we test the hypothesis that nanobubbles can also be observed in nonaqueous solvents in order to ascertain if their anomalous lifetimes and contact angles are related to properties of the solvent. Nanobubbles were seen in the protic solvents formamide, ethylammonium nitrate, and propylammonium nitrate, but not in propylene carbonate or dimethyl sulfoxide. Solvents in which nanobubbles were observed exhibit a three-dimensional hydrogen-bonding network. Like in aqueous systems, the nanobubbles were stable for days and exhibited high contact angles (∼165°). PMID:26153620

  18. Propylene oxide

    Integrated Risk Information System (IRIS)

    Propylene oxide ; CASRN 75 - 56 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  19. Propylene glycol

    Integrated Risk Information System (IRIS)

    Propylene glycol ; CASRN 57 - 55 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  20. A new piece in the puzzle of lithium/air batteries: computational study on the chemical stability of propylene carbonate in the presence of lithium peroxide.

    PubMed

    Laino, Teodoro; Curioni, Alessandro

    2012-03-19

    The electrolyte role in non-aqueous lithium/air batteries is attracting a lot of attention in several research groups, because of its fundamental importance in producing the appropriate reversible electrochemical reduction. While recent published works identify the lithium superoxide as the main degrading agent for propylene carbonate (PC), there is no clear experimental evidence that the oxygen at the cathode interface layer does not reduce further to peroxide before reacting with PC. Here, we investigate the reactivity of lithium peroxide versus propylene carbonate and find that Li(2)O(2) irreversibly decomposes the carbonate solvent, leading to alkyl carbonates. We also show that, compared with a single Li(2)O(2) unit in PC, a crystalline surface of Li(2)O(2) exhibits an enhanced reactivity. Our findings support the possibility that in lithium/air cells, oxygen may still be reduced to peroxide, with the formation of solid Li(2)O(2), which degrades by decomposing PC. PMID:22354790

  1. In-Situ X-ray Deformation Study of Fluorinated Mulitwalled Carbon Nanotube and Fluorinated Ethylene-Propylene Nanocomposite Fibers

    SciTech Connect

    Chen,X.; Burger, C.; Fang, D.; Sics, I.; Wang, X.; He, W.; Somani, R.; Yoon, K.; Hsiao, B.; Chu, B.

    2006-01-01

    A fluorinated multiwalled carbon nanotube (FMWNT) was prepared by reaction of 3-perfluorooctylpropylamine with carboxylic acid groups on the oxidized carbon nanotube surface. The modification was confirmed by TGA, TEM, and solubility tests in a perfluorodecalin solvent. Nanocomposite fibers based on FMWNT and a fluoro-ethylene-propylene (FEP) copolymer were fabricated by melt blending and melt spinning. SEM examination indicated that the dispersion of FMWNT in FEP was significantly better than that of the as-received multiwalled carbon nanotube (MWNT) in FEP. Both yield strength and modulus of the melt-spun FMWNT/FEP nanocomposite fiber increased with increasing FMWNT content, but the elongation-to-break ratio decreased. In-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques were used to follow the structural changes during tensile deformation of melt-spun fibers. In pure FEP fibers, perpendicularly arranged lamellar stacks (with respect to the fiber axis) became tilted at small strains, while destruction of lamellae took place at high strains (>250%), resulting in the rapid decrease of crystallinity. Surprisingly, the tilting of lamellar stacks was not observed in FEP/FMWNT nanocomposite fibers during deformation. We hypothesize that the well-dispersed FMWNT particles form a fibrous network, which can carry a significant fraction of local stress, resulting in overall increases of yield strength and modulus. A possible mechanism to explain the effect of FMWNT on the lamellar structural change in FEP and corresponding mechanical behavior is presented.

  2. The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes.

    PubMed

    Xiang, Hongfa; Mei, Donghai; Yan, Pengfei; Bhattacharya, Priyanka; Burton, Sarah D; von Wald Cresce, Arthur; Cao, Ruiguo; Engelhard, Mark H; Bowden, Mark E; Zhu, Zihua; Polzin, Bryant J; Wang, Chong-Min; Xu, Kang; Zhang, Ji-Guang; Xu, Wu

    2015-09-23

    Despite the potential advantages it brings, such as wider liquid range and lower cost, propylene carbonate (PC) is seldom used in lithium-ion batteries because of its sustained cointercalation into the graphene structure and the eventual graphite exfoliation. Here, we report that cesium cation (Cs(+)) directs the formation of solid electrolyte interphase on graphite anode in PC-rich electrolytes through its preferential solvation by ethylene carbonate (EC) and the subsequent higher reduction potential of the complex cation. Effective suppression of PC-decomposition and graphite-exfoliation is achieved by adjusting the EC/PC ratio in electrolytes to allow a reductive decomposition of Cs(+)-(EC)m (1 ≤ m ≤ 2) complex preceding that of Li(+)-(PC)n (3 ≤ n ≤ 5). Such Cs(+)-directed interphase is stable, ultrathin, and compact, leading to significant improvement in battery performances. In a broader context, the accurate tailoring of interphasial chemistry by introducing a new solvation center represents a fundamental breakthrough in manipulating interfacial reactions that once were elusive to control. PMID:26369297

  3. The Role of Cesium Cation in Controlling Interphasial Chemistry on Graphite Anode in Propylene Carbonate-Rich Electrolytes

    SciTech Connect

    Xiang, Hongfa; Mei, Donghai; Yan, Pengfei; Bhattacharya, Priyanka; Burton, Sarah D.; Cresce, Arthur V.; Cao, Ruiguo; Engelhard, Mark H.; Bowden, Mark E.; Zhu, Zihua; Polzin, Bryant; Wang, Chong M.; Xu, Kang; Zhang, Jiguang; Xu, Wu

    2015-09-10

    Propylene carbonate (PC) is seldom used in lithium-ion batteries (LIBs) due to its sustained co-intercalation into graphene structure and the eventual graphite exfoliation, despite potential advantages it brings, such as wider liquid range and lower cost. Here we discover that cesium cation (Cs+), originally used to suppress dendrite growth of Li metal anode, directs the formation of solid electrolyte interphase (SEI) on graphitic anode in PC-rich electrolytes through preferential solvation. Effective suppression of PC-decomposition and graphite-exfoliation was achieved when the ratio of ethylene carbonate (EC)/PC in electrolytes was so adjusted that the reductive decomposition of Cs+-(EC)m (1≤m≤2) complex precedes that of Li+-(PC)n (3≤n≤5). The interphase directed by Cs+ is stable, ultrathin and compact, leading to significant improvements in LIB performances. In a broader context, the accurate tailoring of SEI chemical composition by introducing a new solvation center represents a fundamental breakthrough in manipulating interfacial reactions processes that once were elusive.

  4. Effect of Fe{sub 3}O{sub 4} nanoparticles on space charge distribution in propylene carbonate under impulse voltage

    SciTech Connect

    Sima, Wenxia Song, He; Yang, Qing; Guo, Hongda; Chen, Qiulin

    2015-12-15

    Addition of nanoparticles of the ferromagnetic material Fe{sub 3}O{sub 4} can increase the positive impulse breakdown voltage of propylene carbonate by 11.65%. To further investigate the effect of ferromagnetic nanoparticles on the space charge distribution in the discharge process, the present work set up a Kerr electro-optic field mapping measurement system using an array photodetector to carry out time-continuous measurement of the electric field and space charge distribution in propylene carbonate before and after modification. Test results show that fast electrons can be captured by Fe{sub 3}O{sub 4} nanoparticles and converted into relatively slow, negatively charged particles, inhibiting the generation and transportation of the space charge, especially the negative space charge.

  5. The development of a bilayer structure of poly(propylene carbonate)/poly(3-hydroxybutyrate) blends from the demixed melt.

    PubMed

    Zhang, Shujing; Sun, Xiaoli; Ren, Zhongjie; Li, Huihui; Yan, Shouke

    2015-12-28

    The miscibility of poly(propylene carbonate) (PPC) and poly(3-hydroxybutyrate) (PHB) blends was analyzed by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results indicated that the blends are immiscible at most blending compositions, and a miscible blend can be obtained when the PHB content is as low as 10 wt%. The morphology of the PPC/PHB (70/30) blend film was characterized by POM, scanning electron micrography (SEM) and Fourier transform infrared spectroscopy (FTIR), and the development of a PPC-top and microporous PHB-bottom bilayer structure can be revealed. Different from the normal case, phase separation can take place on the normal direction of the film surface in the PPC/PHB (70/30) blend at 190 °C, attributed to the different surface energies of the two components. The continuous segregation of PPC to the top-layer can result in the crystallization of PHB at the bottom layer and conversely promote the complete development of a bilayer structure. Since the isotropic PPC layer is transparent with no birefringence, the PHB spherulite with a microporous structure at the bottom layer can be observed directly by POM. Moreover, the microporous structure of the bottom layer should be attributed to the solution cast procedure. Thus, some unique crystalline patterns may be created in the demixed crystalline/amorphous polymer blends, which differ greatly from those obtained from the miscible blend systems. PMID:26577534

  6. Crystallization behavior and thermal stability of poly(butylene succinate)/poly(propylene carbonate) blends prepared by novel vane extruder

    NASA Astrophysics Data System (ADS)

    Chen, Rongyuan; Zou, Wei; Zhang, Haichen; Zhang, Guizhen; Qu, Jinping

    2016-03-01

    This work focused on the study of crystallization behavior and thermal stability of degradable poly(butylene succinate) (PBS) and poly(propylene carbonate) (PPC) blends prepared by vane extruder based on elongation force field, which is novel equipment for polymer processing. Dicumyl peroxide (DCP) was applied in this work as compatibilizer for PBS/PPC blend. Crystallization behavior and melting behavior of the blends were investigated by differential scanning calorimetry (DSC) testing. Thermal stability of the blends was studied by thermogravimetric (TG) testing. Furthermore, the melt flow indices (MFI) of the blends were examined by a MFI instrument. The results showed that the crystallization temperature of PBS decreased with the addition of PPC and DCP. The glass transition temperature of PPC increased and the melting temperature of the blend increased with the addition of PPC and DCP, which indicated that the entanglement between the molecular chains of PBS and PPC was enhanced. Thermogravimetric analysis showed that a two-step decomposition process of the blend occurred due to the different thermal resistance of PBS and PPC, and the addition of PBS reduced the decomposition rate of PPC. Moreover, the addition of PBS improved the melt flow property of PPC.

  7. X-Ray absorption spectroscopy of LiBF4 in propylene carbonate: a model lithium ion battery electrolyte.

    PubMed

    Smith, Jacob W; Lam, Royce K; Sheardy, Alex T; Shih, Orion; Rizzuto, Anthony M; Borodin, Oleg; Harris, Stephen J; Prendergast, David; Saykally, Richard J

    2014-11-21

    Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4 in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li(+) ion in this model electrolyte. By generating linear combinations of the computed spectra of Li(+)-associating and free PC molecules and comparing to the experimental spectrum, we find a Li(+)-solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures. PMID:25175723

  8. Propylene carbonate quantification by its derivative 3,5-diacetyl-1,4-dihydro-2,6-lutidine.

    PubMed

    Grizić, Daris; Heimer, Pascal; Vranić, Edina; Imhof, Diana; Lamprecht, Alf

    2016-05-01

    Propylene carbonate (PC) is a non-toxic solvent currently used in various pharmaceutical formulations. Consequently, a simple, cost-effective and most accurate analytical method for the quantification of this optical inert solvent is of major interest. Based on a consecutive three-step reaction 3,5-diacetyl-1,4-dihydro-2,6-lutidine was obtained from PC and used for quantification by either UV and fluorescent detection. Data were compared with results from LC-ESI-MS as a reference method. After using Mandel's test for linearity assessment of the calibration curves, linear fitting was used for LC-ESI-MS and spectrofluorimetry, while a polynomial 3rd order curve fitting was used for spectrophotometry. High intra- and inter-day precision as well as high accuracy were confirmed for all three analytical methods (spectrophotometry, spectrofluorimetry and LC-ESI-MS). The comparison of all three methods was assessed using correlation coefficients and Bland-Altman plots, both showing satisfying results with a high degree of agreement. The new method confirmed its applicability for PC quantification in two formulations, namely a PC-enriched cream and polyester microimplants. This new quantification method for PC is a reliable alternative to highly sophisticated chromatographic methods. PMID:26946012

  9. Novel polymer electrolytes based on thermoplastic polyurethane and ionic liquid/lithium bis(trifluoromethanesulfonyl)imide/propylene carbonate salt system

    NASA Astrophysics Data System (ADS)

    Lavall, R. L.; Ferrari, S.; Tomasi, C.; Marzantowicz, M.; Quartarone, E.; Magistris, A.; Mustarelli, P.; Lazzaroni, S.; Fagnoni, M.

    Polymer electrolytes were prepared from thermoplastic polyurethane with addition of mixture of ionic liquid N-ethyl(methylether)-N-methylpyrrolidinium trifluoromethanesulfonimmide (PYRA 12O1TFSI), lithium bis(trifluoromethanesulfoneimide) salt and propylene carbonate. The electrolytes characterization was performed by thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy. The electrical properties were investigated in detail by impedance spectroscopy with the aid of equivalent circuit fitting of the impedance spectra. A model describing temperature evolution of ionic conductivity and the properties of electrolyte/blocking electrode interface was developed. The electrochemical stability of the electrolytes was studied by linear voltammetry. Our results indicate that the studied electrolytes have good self-standing characteristics, and also a sufficient level of thermal stability and a fairly good electrochemical window. The ionic conductivity increases with increasing amount of mixture, and the character of temperature dependence of conductivity indicates decoupling of ion transport from polymer matrix. For studied system, the highest value of ionic conductivity measured at room temperature was 10 -4 S cm -1.

  10. Densities and excess molar volumes of binary mixtures containing propylene carbonate + chlorohydrocarbons at 298.15 K and atmospheric pressure

    SciTech Connect

    Comelli, F.; Francesconi, R.

    1995-11-01

    Densities and excess molar volumes, V{sub m}{sup E}, for binary mixtures containing propylene carbonate + 10 chlorohydrocarbons (dichloromethane, 1,2-dichloroethane, 1,3-dichloropropane, 1,4-dichlorobuthane, 1,6-dichlorohexane, 1,10-dichlorodecane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trans-1,2-dichloroethene, and trichloroethene) have been measured at 298.15 K and at atmospheric pressure using an Anton Paar digital vibrating tube density meter. The results are fitted to the Redlich-Kister equation. The values of V{sub m}{sup E} for the mixtures containing dichloroalkanes show an increasing trend with the increase of the chain length and vary from a minimum of {minus}0.24 cm{sup 3}/mol for dichloromethane up to a maximum of +0.31 cm{sup 3}/mol for 1,10-dichlorodecane. The excess molar volumes for the other mixtures are negative over the entire range of composition. Results are qualitatively discussed in terms of molecular interactions.

  11. Kinetics and mechanism of monomolecular heterolysis of framework compounds. IV. Ionization of 1-adamantyl iodide in propylene carbonate

    SciTech Connect

    Ponomareva, E.A.; Tarasenko, P.V.; Yurchenko, A.G.; Dvorko, G.F.

    1987-09-10

    The heterolysis of 1-iodoadamantane in propylene carbonate was studied preparatively and kinetically; v = k (1-AdI), k/sub 25/ = 2.50 x 10/sup -8/ sec/sup -1/, ..delta..H/sup does not equal/ = 90.9 kJ/mole, ..delta..S/sup does not equal/ = -85.5 J/mole x deg. Additions of water, LiClO/sub 4/, and Et/sub 4/N/sup +/ClO/sub 4//sup -/ increase and additions of Et/sub 4/N/sup +/I/sup -/, LiBr, Et/sub 4/N/sup +/Br..sqrt.., Bu/sub 4/N/sup +/Br/sup -/, Et/sup 4/N/sup +/Cl/sup -/, LiPic, and Et/sub 4/N/sup +/Pic/sup -/ reduce the reaction rate. It is suggested that a sterically separated ion pair is formed in the rate-controlling stage and is quickly transformed into a solvent-separated ion pair, which then gives the reaction products. The negative salt effect is due to the action of the salt on the sterically separated ion pair.

  12. X-ray absorption spectroscopy of LiBF 4 in propylene carbonate. A model lithium ion battery electrolyte

    DOE PAGESBeta

    Smith, Jacob W.; Lam, Royce K.; Sheardy, Alex T.; Shih, Orion; Rizzuto, Anthony M.; Borodin, Oleg; Harris, Stephen J.; Prendergast, David; Saykally, Richard J.

    2014-08-20

    Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4 in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li+ ion in this model electrolyte.more » By generating linear combinations of the computed spectra of Li+-associating and free PC molecules and comparing to the experimental spectrum, we find a Li+–solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures.« less

  13. Preparation, melting behavior and thermal stability of poly(lactic acid)/poly(propylene carbonate) blends processed by vane extruder

    NASA Astrophysics Data System (ADS)

    Zou, Wei; Chen, Rongyuan; Zhang, Haichen; Qu, Jinping

    2016-03-01

    Poly (lactic acid) (PLA)/Poly (propylene carbonate) (PPC) blends were prepared by vane extruder which is a type of novel polymer processing extruder based on elongation force field. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric (TG) were used respectively to analyze the compatibility, the melting behavior and thermal stability properties of PLA/PPC blends affected by the different content of PPC. The results showed that with the increase of the PPC content, the glass transition temperature of PLA was reduced, and the glass transition temperature of PPC was increased, which indicated that PLA and PPC had partial compatibility. The cold crystallization temperature of PLA increased with the increase of the PPC content, which showed that PPC hindered the cold crystallization process of PLA. The addition of PPC had little impact on the melting process of PLA, and the melting temperature of PLA was almost kept the same value. Thermogravimetric analysis showed that the thermal stability of PPC was worse than that of PLA, the addition of PPC reduced the thermal stability of PLA.

  14. Observation of strong nano-effect via tuning distributed architecture of graphene oxide in poly(propylene carbonate)

    NASA Astrophysics Data System (ADS)

    Gao, Jian; Bai, Hongwei; Zhou, Xin; Yang, Guanghui; Xu, Chenlong; Zhang, Qin; Chen, Feng; Fu, Qiang

    2014-01-01

    For optimum reinforcement in polymer nanocomposite, a critical challenge is to realize the full ‘nano-effect’ of nanofillers at a high content, which is largely hindered by the strong tendency to aggregation of nanofillers. Here, by using a solvent-exchange and solution casting approach, we could incorporate a high-content graphene oxide (GO) into a soft biodegradable CO2-based poly(propylene carbonate) (PPC) up to 20 wt% with excellent dispersion. Based on this, the distributed architecture of GO could be tuned from a ‘GO dotted dispersion’ and ‘GO network’ to strong ‘GO co-continuous structure’ with increasing GO content. As a result, a very strong ‘nano-effect’ of GO in the PPC matrix was observed: (1) the glass transition temperature of PPC was improved from 25 to 45 ° C for slightly confined molecular chains, and even to 100 ° C for highly confined ones; (2) the modified PPC showed drastically enhanced high-temperature mechanical properties, comparable to those of traditional polymers such as polypropylene (PP) and biopolymer poly(lactic acid) (PLA); and (3) such modified PPC exhibited an exciting solvent resistance compared to neat PPC. Our work provides an example to improve the high-temperature properties of a polymer via formation of filler co-continuous structure.

  15. Reinforced Poly(Propylene Carbonate) Composite with Enhanced and Tunable Characteristics, an Alternative for Poly(lactic Acid).

    PubMed

    Manavitehrani, Iman; Fathi, Ali; Wang, Yiwei; Maitz, Peter K; Dehghani, Fariba

    2015-10-14

    The acidic nature of the degradation products of polyesters often leads to unpredictable clinical complications, such as necrosis of host tissues and massive immune cell invasions. In this study, poly(propylene carbonate) (PPC) and starch composite is introduced with superior characteristics as an alternative to polyester-based polymers. The degradation products of PPC-starch composites are mainly carbon dioxide and water; hence, the associated risks to the acidic degradation of polyesters are minimized. Moreover, the compression strength of PPC-starch composites can be tuned over the range of 0.2±0.03 MPa to 33.9±1.51 MPa by changing the starch contents of composites to address different clinical needs. More importantly, the addition of 50 wt % starch enhances the thermal processing capacity of the composites by elevating their decomposition temperature from 245 to 276 °C. Therefore, thermal processing methods, such as extrusion and hot melt compression methods can be used to generate different shapes and structures from PPC-starch composites. We also demonstrated the cytocompatibility and biocompatibility of these composites by conducting in vitro and in vivo tests. For instance, the numbers of osteoblast cells were increased 2.5 fold after 7 days post culture. In addition, PPC composites in subcutaneous mice model resulted in mild inflammatory responses (e.g., the formation of fibrotic tissue) that were diminished from two to 4 weeks postimplantation. The long-term in vivo biodegradation of PPC composites are compared with poly(lactic acid) (PLA). The histochemical analysis revealed that after 8 weeks, the biodegradation of PLA leads to massive immune cell infusion and inflammation at the site, whereas the PPC composites are well-tolerated in vivo. All these results underline the favorable properties of PPC-starch composites as a benign biodegradable biomaterial for fabrication of biomedical implants. PMID:26376751

  16. HETERODIMERIZATION OF PROPYLENE AND VINYLARENES: FUNCTIONAL GROUP COMPATIBILITY IN A HIGHLY EFFICIENT NI-CATALYZED CARBON-CARBON BOND-FORMING REACTION. (R826120)

    EPA Science Inventory

    Abstract

    Unlike heterodimerization reactions of ethylene and vinylarenes, no such synthetically useful reactions using propylene are known. We find that propylene reacts with various vinylarenes in the presence of catalytic amounts of [(allyl)NiBr]2, triphen...

  17. Protective efficacy of menthol propylene glycol carbonate compared to N, N-diethyl-methylbenzamide against mosquito bites in Northern Tanzania

    PubMed Central

    2012-01-01

    Background The reduction of malaria parasite transmission by preventing human-vector contact is critical in lowering disease transmission and its outcomes. This underscores the need for effective and long lasting arthropod/insect repellents. Despite the reduction in malaria transmission and outcomes in Tanzania, personal protection against mosquito bites is still not well investigated. This study sought to determine the efficacy of menthol propylene glycol carbonate (MR08), Ocimum suave as compared to the gold standard repellent N, N-diethyl-methylbenzamide (DEET), either as a single dose or in combination (blend), both in the laboratory and in the field against Anopheles gambiae s.l and Culex quinquefasciatus. Methods In the laboratory evaluations, repellents were applied on one arm while the other arm of the same individual was treated with a base cream. Each arm was separately exposed in cages with unfed female mosquitoes. Repellents were evaluated either as a single dose or as a blend. Efficacy of each repellent was determined by the number of mosquitoes that landed and fed on treated arms as compared to the control or among them. In the field, evaluations were performed by human landing catches at hourly intervals from 18:00 hr to 01:00 hr. Results A total of 2,442 mosquitoes were collected during field evaluations, of which 2,376 (97.30%) were An. gambiae s.l while 66 (2.70%) were Cx. quinquefaciatus. MR08 and DEET had comparatively similar protective efficacy ranging from 92% to 100 for both single compound and blends. These findings indicate that MR08 has a similar protective efficacy as DEET for personal protection outside bed nets when used singly and in blends. Because of the personal protection provided by MR08, DEET and blends as topical applicants in laboratory and field situations, these findings suggest that, these repellents could be used efficiently in the community to complement existing tools. Overall, Cx. quinquefasciatus were significantly

  18. The influence of starch oxidization and aluminate coupling agent on interfacial interaction, rheological behavior, mechanical and thermal properties of poly(propylene carbonate)/starch blends

    NASA Astrophysics Data System (ADS)

    Jiang, Guo; Zhang, Shui-Dong; Huang, Han-Xiong; The Key Laboratory of Polymer Processing Engineering of the Ministry of Education Team

    Poly(propylene carbonate) (PPC) is a kind of new biodegradable polymer that is synthesized by copolymerization of propylene oxide and carbon dioxide. In this work, PPC end-capped with maleic anhydride (PPCMA)/thermoplastic starch (TPS), PPCMA/thermoplastic oxidized starch (TPOS) and PPCMA/AL-TPOS (TPOS modified by aluminate coupling agent) blends were prepared by melt blending to improve its thermal and mechanical properties. FTIR results showed that there existed hydrogen-bonding interaction between PPCMA and starch. SEM observation revealed that the compatibility between PPCMA and TPOS was improved by the oxidation of starch. The enhanced interfacial interactions between PPCMA and TPOS led to a better performance of PPC blends such as storage modulus (G'), loss modulus (G''), complex viscosity (η*), tensile strength and thermal properties. Furthermore, the modification of TPOS by aluminate coupling agent (AL) facilitated the dispersion of oxidized starch in PPC matrix, and resulted in increasing the tensile strength and thermal stability. National Natural Science Foundation of China, National Science Fund of Guangdong Province.

  19. Electronic structure of the acetonitrile and acetonitrile dimer anions: a topological investigation.

    PubMed

    Timerghazin, Qadir K; Peslherbe, Gilles H

    2008-01-17

    Acetonitrile molecules are known for their intriguing ability to accommodate an excess electron in either a diffuse dipole-bound orbital, away from the valence electrons, or in its valence orbitals, depending on the environment. In this work, we report a computational investigation of the monomer and dimer acetonitrile anions, with the main goal of gaining further insight into the unusual electronic structure of these species. To this end, the topology of the electron density distribution has been examined in detail with the quantum theory of atoms in molecules (AIM). The excess electron is found to affect the topology of the electron density very differently for two dipole-bound-electron isomers of the acetonitrile dimer anion: for the head-to-tail isomer, the electron density simply decays away from the atomic nuclei, and the presence of the excess electron only manifests itself in the Laplacian of the electron density as a very diffuse region of "dipole-bound" charge concentration; in contrast, for the "solvated-electron" head-to-head isomer, a maximum of electron density without a corresponding atomic nucleus is observed, which topologically corresponds to a pseudo-atom of electron density. The acetonitrile dimer appears to be the smallest solvent cluster anion to exhibit such a non-nuclear attractor due to the presence of a solvated electron. Although the "solvated-electron" isomer is thermodynamically less stable than the head-to-tail isomer at 0 K, its floppy nature leads to a higher vibrational entropy that makes it the most stable acetonitrile dimer, anionic or neutral, above 150 K. As for the acetonitrile dimer anion with a valence-bound electron, its structure is characterized by acetonitrile molecules connected to each other at the cyanide carbon atoms; the AIM analysis reveals that, although this C-C bond is relatively weak, with an estimated bond order of 0.6, it possesses genuine covalent character and is not a "pseudo-bond" as previously speculated

  20. Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

    PubMed Central

    Jeon, Jong Yeob; Eo, Seong Chan; Varghese, Jobi Kodiyan

    2014-01-01

    Summary The (salen)Co(III) complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO2/epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA) copolymerizations and PO/CO2/PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalate)s were afforded without any formation of ether linkages. In the PO/CO2/PA terpolymerizations, full conversion of PA was also achieved within 4 h. The resulting polymers were gradient poly(1,2-propylene carbonate-co-phthalate)s because of the drift in the PA concentration during the terpolymerization. Both polymerizations showed immortal polymerization character; therefore, the molecular weights were determined by the activity (g/mol-1) and the number of chain-growing sites per 1 [anions in 1 (5) + water (present as impurity) + ethanol (deliberately fed)], and the molecular weight distributions were narrow (M w/M n, 1.05–1.5). Because of the extremely high activity of 1, high-molecular-weight polymers were generated (M n up to 170,000 and 350,000 for the PO/PA copolymerization and PO/CO2/PA terpolymerization, respectively). The terpolymers bearing a substantial number of PA units (f PA, 0.23) showed a higher glass-transition temperature (48 °C) than the CO2/PO alternating copolymer (40 °C). PMID:25161738

  1. Conductivity, Mechanical and Thermal Studies on Poly(methyl methacrylate)-Based Polymer Electrolytes Complexed with Lithium Tetraborate and Propylene Carbonate

    NASA Astrophysics Data System (ADS)

    Ramesh, S.; Bing, Khoo Ne

    2012-01-01

    A series of different composition ratio of polymer electrolytes based on poly(methyl methacrylate) (PMMA) as host polymer, lithium tetraborate (Li2B4O7) as salt, and propylene carbonate (PC) as plasticizer is produced by solution casting method. Fourier transform infrared (FTIR) spectroscopy studies are used to confirm the formation of polymer electrolyte complex. PMMA: Li2B4O7: PC (52.5:22.5:25.0 wt.%) is obtained as the highest conducting polymer electrolyte with a conductivity of 5.14 × 10-6 S/cm at room temperature (23 °C). The temperature-dependent conductivity of the polymer films shows Arrhenius-like behavior which reveals that the charge carriers move in a liquid-like environment. The addition of PC decreases the Young's modulus and stress at peak values of the complexes. Thermogravimetric analysis (TGA) is employed to study the thermal stability of the electrolytes.

  2. Time-dependent electrochromism of nanocrystalline TiO{sub 2} films in propylene carbonate solution of LiClO{sub 4}

    SciTech Connect

    Kang, T.S.; Kim, D.; Kim, K.J.

    1998-06-01

    Electrochromism of nanocrystalline TiO{sub 2} films under cathodic bias in propylene carbonate containing LiClO{sub 4} was studied by time-dependent absorption and fluorescence spectroscopies. The absorption spectra revealed two absorption bands near 700 and 420 nm. The absorption band near 700 nm showed a blue shift and an increase in absorbance with time. The blue shift seemed to be due to the progressive involvement of the trapped electrons in the lower energy levels within the shallow surface states. The newly observed band near 420 nm appeared to have originated from the deep surface states which, lying 1.3--1.8 eV below the conduction band, were gradually filled with electrons in the shallow surface states.

  3. NMR T{sub 1} relaxation time measurements and calculations with translational and rotational components for liquid electrolytes containing LiBF{sub 4} and propylene carbonate

    SciTech Connect

    Richardson, P. M. Voice, A. M. Ward, I. M.

    2013-12-07

    Longitudinal relaxation (T{sub 1}) measurements of {sup 19}F, {sup 7}Li, and {sup 1}H in propylene carbonate/LiBF{sub 4} liquid electrolytes are reported. Comparison of T{sub 1} values with those for the transverse relaxation time (T{sub 2}) confirm that the measurements are in the high temperature (low correlation time) limit of the T{sub 1} minimum. Using data from pulsed field gradient measurements of self-diffusion coefficients and measurements of solution viscosity measured elsewhere, it is concluded that although in general there are contributions to T{sub 1} from both translational and rotational motions. For the lithium ions, this is mainly translational, and for the fluorine ions mainly rotational.

  4. Detection of adulteration in acetonitrile

    NASA Astrophysics Data System (ADS)

    Chen, Guoxiang; Fujimori, Kiyoshi; Lee, Hans; Nashed-Samuel, Yasser; Phillips, Joseph; Rogers, Gary; Shen, Hong; Yee, Chanel

    2011-05-01

    To address the increasing concern that acetonitrile may be intentionally adulterated to meet the shortfall in global supplies resulting from a downturn in its manufacturing, three analytical techniques were examined in this study. Gas Chromatography with Thermal Conductivity Detection (GC-TCD), Near Infrared (NIR) spectroscopy and Fourier Transform Infrared (FT-IR) spectroscopy were assessed for their ability to detect and quantify potential adulterants including water, alternative organic solvents, and by-products associated with the production of acetonitrile. The results of the assessment of the three techniques for acetonitrile adulteration testing are discussed.

  5. Synthesis of Cu, Zn and Cu/Zn brass alloy nanoparticles from metal amidinate precursors in ionic liquids or propylene carbonate with relevance to methanol synthesis

    NASA Astrophysics Data System (ADS)

    Schütte, Kai; Meyer, Hajo; Gemel, Christian; Barthel, Juri; Fischer, Roland A.; Janiak, Christoph

    2014-02-01

    Microwave-induced decomposition of the transition metal amidinates {[Me(C(NiPr)2)]Cu}2 (1) and [Me(C(NiPr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry. Microstructure characterizations were complemented by STEM with spatially resolved energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Synthesis in ILs yields significantly smaller nanoparticles than in PC. β-CuZn alloy nanoparticles are precursors to catalysts for methanol synthesis from the synthesis gas H2/CO/CO2 with a productivity of 10.7 mol(MeOH) (kg(Cu) h)-1.Microwave-induced decomposition of the transition metal amidinates {[Me(C(NiPr)2)]Cu}2 (1) and [Me(C(NiPr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry. Microstructure characterizations were complemented by STEM with spatially resolved energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Synthesis in ILs yields significantly smaller nanoparticles than in PC.

  6. Discussion on the complexing ability of the uranyl ion with several crown ethers and cryptands in water and in propylene carbonate

    SciTech Connect

    Brighli, M.; Fux, P.; Lagrange, J.; Lagrange, P.

    1985-01-02

    Interactions of the uranyl ion (UO/sub 2//sup 2 +/) with some common crown ethers (12C4, 15C5, 18C6, DB-18C6) and cryptands (22,222) are investigated in aqueous and propylene carbonate (PC) solutions, I = 0.1 M ((TEA)ClO/sub 4/). Stability constants of the complexes formed are determined by potentiometric and spectrophotometric measurements. Discussions on the stability constants of the complexes allow us to postulate whether or not direct uranyl-macrocycle bonds are obtained. In PC solution, uranyl inner-sphere complexes with 18C6, DB-18C6, 22, and 222 are formed with the uranyl ion probably inside or partially enclosed in the ligand cavity. In aqueous media, complexation occurs only with crown ethers by formation of hydrogen bonds between hydrogen of water molecules of the hydrate shell of the uranyl ion and oxygen atoms of the crown ether (UO/sub 2//sup 2 +/ outer-sphere complexes). 31 references, 5 figures, 3 tables.

  7. Association constants in solutions of lithium salts in butyrolactone and a mixture of propylene carbonate with 1,2-dimethoxyethane (1 : 1), according to conductometric data

    NASA Astrophysics Data System (ADS)

    Chernozhuk, T. V.; Sherstyuk, Yu. S.; Novikov, D. O.; Kalugin, O. N.

    2016-02-01

    A conductometric study is performed with solutions of lithium bis(oxalato)borate (LiBOB) in γ-butyrolactone (γ-BL) at 278.15-388.15 K and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), LiBOB, and lithium tetrafluoroborate (LiBF4) in mixtures of propylene carbonate and 1,2-dimethoxyethane (PC + 1,2-DME) (1 : 1) at 278.15-348.15 K. Limiting molar electrical conductivities (LMECs) and association constants ( K a) in the studied solutions of electrolytes are determined using the Lee-Wheaton equation. The effect temperature, the nature of the solvent, and the properties of the anion have on the conductivity and interparticle interactions in solutions of lithium salts in γ-BL and PC + 1,2-DME (1 : 1) is established. It was concluded that the studied solutions are characterized by low values of their association constants. It was found that the BOB;- anion destroys the structure of the solvent.The thickness of the dynamic solvation shell of ions (Δ R) remains constant for both solvents over the studied range of temperatures, and Δ R is significantly greater for Li+ than for other ions.

  8. X-ray absorption spectroscopy of LiBF 4 in propylene carbonate. A model lithium ion battery electrolyte

    SciTech Connect

    Smith, Jacob W.; Lam, Royce K.; Sheardy, Alex T.; Shih, Orion; Rizzuto, Anthony M.; Borodin, Oleg; Harris, Stephen J.; Prendergast, David; Saykally, Richard J.

    2014-08-20

    Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4 in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li+ ion in this model electrolyte. By generating linear combinations of the computed spectra of Li+-associating and free PC molecules and comparing to the experimental spectrum, we find a Li+–solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures.

  9. An investigation of composite electrolytes by mixing polyethylene oxide- and polytetramethylene glycol-based waterborne polyurethane with the addition of LiClO{sub 4}/propylene carbonate

    SciTech Connect

    Wen, T.C.; Chang, J.S.; Cheng, T.T.

    1998-10-01

    Various composite electrolytes (CE) were prepared by mixing polytetramethylene glycol-based waterborne polyurethane [WPU(PTMG)], polyethylene oxide (PEO), and LiClO{sub 4}/propylene carbonate (PC). The conductivity of these CEs was investigated using ac impedance. Differential scanning calorimetry (DSC) and polarizing microscopy (PM) were employed for material characterization. The temperature dependence of the conductivity follows the Arrhenius law for samples with a LiClO{sub 4}/PC content larger than 30%, while for samples with LiClO{sub 4}/PC content approximating 8%, it shows linear segments separated by a transition zone between 25 and 65 C. According to the ac and DSC results, the conductivity is increased, and the melting temperature is decreased by increasing the LiClO{sub 4}/PC content. PM results indicate that the increase in PEO ratio increases the crystallinity of the PEO-WPU(PTMG) films. When LiClO{sub 4}/PC is added, the increase in PEO ratio results in an increase in conductivity. The CE comprising 33% PEO, 17% WPU(PTMG), and 50% LiClO{sub 4}/PC exhibits conductivities as high as Ca. {approximately}10{sup {minus}2} S/cm at 85 C and 5 {times} 10{sup {minus}3} S/cm at 15 C.

  10. Effects of Propylene Carbonate Content in CsPF₆-Containing Electrolytes on the Enhanced Performances of Graphite Electrode for Lithium-Ion Batteries.

    PubMed

    Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo; Xiang, Hongfa; Engelhard, Mark H; Polzin, Bryant J; Wang, Chongmin; Zhang, Ji-Guang; Xu, Wu

    2016-03-01

    The effects of propylene carbonate (PC) content in CsPF6-containing electrolytes on the performances of graphite electrode in lithium half cells and in graphite∥LiNi0.80Co0.15Al0.05O2 (NCA) full cells are investigated. It is found that the performance of graphite electrode is significantly affected by PC content in the CsPF6-containing electrolytes. An optimal PC content of 20% by weight in the solvent mixtures is identified. The enhanced electrochemical performance of graphite electrode can be attributed to the synergistic effects of the PC solvent and the Cs(+) additive. The synergistic effects of Cs(+) additive and appropriate amount of PC enable the formation of a robust, ultrathin, and compact solid electrolyte interphase (SEI) layer on the surface of graphite electrode, which is only permeable for desolvated Li(+) ions and allows fast Li(+) ion transport through it. Therefore, this SEI layer effectively suppresses the PC cointercalation and largely alleviates the Li dendrite formation on graphite electrode during lithiation even at relatively high current densities. The presence of low-melting-point PC solvent improves the sustainable operation of graphite∥NCA full cells under a wide temperature range. The fundamental findings also shed light on the importance of manipulating/maintaining the electrode/electrolyte interphasial stability in various energy-storage devices. PMID:26862677

  11. Synthesis of Cu, Zn and Cu/Zn brass alloy nanoparticles from metal amidinate precursors in ionic liquids or propylene carbonate with relevance to methanol synthesis.

    PubMed

    Schütte, Kai; Meyer, Hajo; Gemel, Christian; Barthel, Juri; Fischer, Roland A; Janiak, Christoph

    2014-03-21

    Microwave-induced decomposition of the transition metal amidinates {[Me(C(N(i)Pr)2)]Cu}2 (1) and [Me(C(N(i)Pr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry. Microstructure characterizations were complemented by STEM with spatially resolved energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Synthesis in ILs yields significantly smaller nanoparticles than in PC. β-CuZn alloy nanoparticles are precursors to catalysts for methanol synthesis from the synthesis gas H2/CO/CO2 with a productivity of 10.7 mol(MeOH) (kg(Cu) h)(-1). PMID:24492885

  12. Direct catalytic asymmetric addition of acetonitrile to N-thiophosphinoylimines.

    PubMed

    Kawato, Yuji; Kumagai, Naoya; Shibasaki, Masakatsu

    2013-12-11

    Direct catalytic addition of acetonitrile pronucleophiles to thiophosphinoylimines is described. Soft Lewis acid-hard Brønsted base cooperative catalysis is crucial to promote this elusive carbon-carbon bond-forming reaction in an enantioselective fashion. PMID:24158566

  13. Solid-state drawing of post-consumer isotactic poly(propylene): Effect of melt filtration and carbon black on structural and mechanical properties.

    PubMed

    Luijsterburg, B J; Jobse, P S; Spoelstra, A B; Goossens, J G P

    2016-08-01

    Post-consumer plastic waste obtained via mechanical recycling is usually applied in thick-walled products, because of the low mechanical strength due to the presence of contaminants. In fact, sorted post-consumer isotactic poly(propylene) (i-PP) can be considered as a blend of 95% i-PP and 5% poly(ethylene), with traces of poly(ethylene terephthalate) (PET). By applying a treatment such as solid-state drawing (SSD) after melt extrusion, the polymer chains can be oriented in one direction, thereby improving the stiffness and tensile strength. In this research, molecular processes such as crystal break-up and chain orientation of these complex blends were monitored as a function of draw ratio. The melt filter mesh size - used to exclude rigid PET particles - and the addition of carbon black (CB) - often added for coloration in the recycling industry - were varied to investigate their influence on the SSD process. This research shows that despite the blend complexity, the molecular processes during SSD compare to virgin i-PP and that similar draw ratios can be obtained (λmax=20), albeit at reduced stiffness and strength as a result of the foreign polymers present in post-consumer i-PP. It is observed that the process stability improves with decreasing mesh size and that higher draw ratios can be obtained. The addition of carbon black, which resides in the dispersed PE phase, also stabilizes the SSD process. Compared to isotropic post-consumer i-PP, the stiffness can be improved by a factor 10 to over 11GPa, while the tensile strength can be improved by a factor 15-385MPa, which is approx. 70% of the maximum tensile strength achieved for virgin i-PP. PMID:27216728

  14. A Study of Electrochemical Reduction of Ethylene and PropyleneCarbonate Electrolytes on Graphite Using ATR-FTIR Spectroscopy

    SciTech Connect

    Zhuang, Guorong V.; Yang, Hui; Blizanac, Berislav; Ross Jr.,Philip N.

    2005-05-12

    We present results testing the hypothesis that there is a different reaction pathway for the electrochemical reduction of PC versus EC-based electrolytes at graphite electrodes with LiPF6 as the salt in common. We examined the reduction products formed using ex-situ Fourier Transform Infrared (FTIR) spectroscopy in attenuated total reflection (ATR) geometry. The results show the pathway for reduction of PC leads nearly entirely to lithium carbonate as the solid product (and presumably ethylene gas as the co-product) while EC follows a path producing a mixture of organic and inorganic compounds. Possible explanations for the difference in reaction pathway are discussed.

  15. Propylene glycol monoethyl ether

    Integrated Risk Information System (IRIS)

    Propylene glycol monoethyl ether ; CASRN 52125 - 53 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments fo

  16. Influence of temperature and electrolyte on the performance of activated-carbon supercapacitors

    NASA Astrophysics Data System (ADS)

    Liu, Ping; Verbrugge, Mark; Soukiazian, Souren

    For hybrid electric vehicle traction applications, energy storage devices with high power density and energy efficiency are required. A primary attribute of supercapacitors is that they retain their high power density and energy efficiency even at -30 °C, the lowest temperature at which unassisted starting must be provided to customers. More abuse-tolerant electrolytes are preferred to the high-conductivity acetonitrile-based systems commonly employed. Propylene carbonate based electrolytes are a promising alternative. In this work, we compare the electrochemical performance of two high-power density electrical double layer supercapacitors employing acetonitrile and propylene carbonate as solvents. From this study, we are able to elucidate phenomena that control the resistance of supercapacitor at lower temperatures, and quantify the difference in performance associated with the two electrolytes.

  17. Propylene from renewable resources: catalytic conversion of glycerol into propylene.

    PubMed

    Yu, Lei; Yuan, Jing; Zhang, Qi; Liu, Yong-Mei; He, He-Yong; Fan, Kang-Nian; Cao, Yong

    2014-03-01

    Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene. PMID:24578188

  18. Adsorptive separation of propylene-propane mixtures

    SciTech Connect

    Jaervelin, H.; Fair, J.R. )

    1993-10-01

    The separation of propylene-propane mixtures is of great commercial importance and is carried out by fractional distillation. It is claimed to be the most energy-intensive distillation practiced in the United States. The purpose of this paper is to describe experimental work that suggests a practical alternative to distillation for separating the C[sub 3] hydrocarbons: adsorption. As studied, the process involves three adsorptive steps: initial separation with molecular sieves with heavy dilution with an inert gas; separation of propylene and propane separately from the inert gas, using activated carbon; and drying of the product streams with any of several available desiccants. The research information presented here deals with the initial step and includes both equilibrium and kinetic data. Isotherms are provided for propylene and propane adsorbed on three zeolites, activated alumina, silica gel, and coconut-based activated carbon. Breakthrough data are provided for both adsorption and regeneration steps for the zeolites, which were found to be superior to the other adsorbents for breakthrough separations. A flow diagram for the complete proposed process is included.

  19. Delayed cyanide poisoning following acetonitrile ingestion.

    PubMed Central

    Mueller, M.; Borland, C.

    1997-01-01

    Acetonitrile (methyl cyanide) is a common industrial organic solvent but is a rare cause of poisoning. We report the first recorded UK case. Acetonitrile is slowly converted to cyanide, resulting in delayed toxicity. We describe a case of deliberate self-poisoning by a 39-year-old woman resulting in cyanide poisoning 11 hours later which was successfully treated by repeated boluses of sodium nitrite and thiosulphate. The half-life of conversion of acetonitrile was 40 hours and harmful blood cyanide levels persisted for over 24 hours after ingestion. Departments treating or advising in cases of poisoning need to be aware of the delayed toxicity of acetonitrile. Monitoring in an intensive care unit of cases of acetonitrile poisoning should continue for 24-48 hours. PMID:9196706

  20. 21 CFR 184.1666 - Propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Propylene glycol. 184.1666 Section 184.1666 Food... GRAS § 184.1666 Propylene glycol. (a) Propylene glycol (C3H8O2, CAS Reg. No. 57-55-6) is known as 1,2-propanediol. It does not occur in nature. Propylene glycol is manufactured by treating propylene...

  1. Photochemistry of nitrate ion in acetonitrile

    NASA Astrophysics Data System (ADS)

    Meera, N.; Ramamurthy, P.

    1988-12-01

    The photochemistry of cobalt(II) nitrate in acetonitrile is investigated using steady-state and flash photolysis techniques. Formation of NO 3• radical has been observed as an intermediate by direct photolysis of nitrate ion and the reaction of the nitrate radical with the solvent is observed as a transient absorption around 600 nm in air-equilibrated acetonitrile. Nitrite ion forms as a product through a collision electron transfer complex intermediate.

  2. Construction materials for reaction unit in the liquid-phase synthesis of propylene oxide

    SciTech Connect

    Zaritskii, V.I.D.

    1987-09-01

    The main components of the reaction medium in equipment for the synthesis of propylene oxide by liquid-phase oxidation of gaseous propylene with peracetic acid are propylene, peracetic acid, ethyl acetate, acetic acid, propylene oxide, carbon dioxide, oxygen, methane, and propylene glycol acetates. The operating conditions of the equipment and content of the main components of the medium are shown. Results are given for the investigation of the corrosion behavior of 12Kh18N10T, 10Kh17N13M2T, 08Kh22N6T, and 08Kh21N6M2T steels, AD0 and AD1 aluminum, and VT1-0 titanium. VSt3 carbon steel was tested for comparison.

  3. 21 CFR 184.1666 - Propylene glycol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Propylene glycol. 184.1666 Section 184.1666 Food... Specific Substances Affirmed as GRAS § 184.1666 Propylene glycol. (a) Propylene glycol (C3H8O2, CAS Reg. No. 57-55-6) is known as 1,2-propanediol. It does not occur in nature. Propylene glycol is...

  4. 21 CFR 184.1666 - Propylene glycol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Propylene glycol. 184.1666 Section 184.1666 Food... Specific Substances Affirmed as GRAS § 184.1666 Propylene glycol. (a) Propylene glycol (C3H8O2, CAS Reg. No. 57-55-6) is known as 1,2-propanediol. It does not occur in nature. Propylene glycol is...

  5. Acetonitrile in the air over Europe

    SciTech Connect

    Hamm, S.; Helas, G.; Warneck, P.

    1989-06-01

    A gas chromatographic technique was developed to measure acetonitrile mixing ratios in air samples collected during three aircraft flights over Europe. Uniform mixing ratios were observed in the troposphere independent of altitude, with an average of 144+-26 pptv for the first two flights, and 194+-7 pptv for the third. /copyright/ American Geophysical Union 1989

  6. RUMINAL FERMENTATION OF PROPYLENE GLYCOL AND GLYCEROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in dec...

  7. 77 FR 28493 - Propylene Oxide; Tolerance Actions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ...EPA is establishing the tree nut crop group tolerance and separate tolerances on pistachio and pine nuts for both the fumigant propylene oxide and the reaction product from the use of propylene oxide, known as propylene chlorohydrin, to cover all registered uses on raw and processed nuts. Also, in accordance with current Agency practice, EPA is making minor revisions to tolerance expressions......

  8. 21 CFR 582.1666 - Propylene glycol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Propylene glycol. 582.1666 Section 582.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1666 Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This...

  9. 21 CFR 582.4666 - Propylene glycol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Propylene glycol. 582.4666 Section 582.4666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This substance is...

  10. 21 CFR 582.4666 - Propylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propylene glycol. 582.4666 Section 582.4666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This substance is...

  11. 21 CFR 582.1666 - Propylene glycol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Propylene glycol. 582.1666 Section 582.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1666 Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This...

  12. 21 CFR 582.1666 - Propylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propylene glycol. 582.1666 Section 582.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1666 Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This...

  13. 21 CFR 582.1666 - Propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Propylene glycol. 582.1666 Section 582.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1666 Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This...

  14. 21 CFR 582.4666 - Propylene glycol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Propylene glycol. 582.4666 Section 582.4666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This substance is...

  15. 21 CFR 582.4666 - Propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Propylene glycol. 582.4666 Section 582.4666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This substance is...

  16. 21 CFR 582.4666 - Propylene glycol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Propylene glycol. 582.4666 Section 582.4666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This substance is...

  17. 21 CFR 582.1666 - Propylene glycol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Propylene glycol. 582.1666 Section 582.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1666 Propylene glycol. (a) Product. Propylene glycol. (b) Conditions of use. This...

  18. Propylene glycol monomethyl ether (PGME)

    Integrated Risk Information System (IRIS)

    Propylene glycol monomethyl ether ( PGME ) ; CASRN 107 - 98 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assess

  19. Diagnosis and misdiagnosis of poisoning with the cyanide precursor acetonitrile: nail polish remover or nail glue remover?

    PubMed

    Rainey, P M; Roberts, W L

    1993-03-01

    Accurate diagnosis of acetonitrile ingestion is critical to management. Often this involves differentiating nail polish remover (acetone) from nail glue remover (acetonitrile). Initial symptoms of acetonitrile ingestion are indistinguishable from those of acetone and common alcohols. However, acetonitrile is metabolized to cyanide, producing severe delayed toxicity. Acetonitrile produced increased serum osmolality and osmolal gap, but these findings are non-specific and normal values cannot rule out potentially fatal exposure. Acetone, but not acetonitrile, was detectable in urine or serum with Acetest tablets; both were unreactive with a ketone dipstick. Acetone and acetonitrile could be detected with routine gas chromatography methods for alcohols. Both substances had identical retention times on the widely used stationary phase, 5% Carbowax 20M on graphitized carbon, and with GasChrom 254. Three other systems afforded unique retention times, but acetonitrile was easily mistaken for ethanol in two. Physicians and laboratories must take care to avoid misdiagnosis of acetonitrile ingestion as exposure to acetone, ethanol or another alcohol. PMID:8476448

  20. Propylene Glycol Poisoning From Excess Whiskey Ingestion

    PubMed Central

    Ku, Kevin; Sue, Gloria R.

    2015-01-01

    In this report, we describe a case of high anion gap metabolic acidosis with a significant osmolal gap attributed to the ingestion of liquor containing propylene glycol. Recently, several reports have characterized severe lactic acidosis occurring in the setting of iatrogenic unintentional overdosing of medications that use propylene glycol as a diluent, including lorazepam and diazepam. To date, no studies have explored potential effects of excess propylene glycol in the setting of alcohol intoxication. Our patient endorsed drinking large volumes of cinnamon flavored whiskey, which was likely Fireball Cinnamon Whisky. To our knowledge, this is the first case of propylene glycol toxicity from an intentional ingestion of liquor containing propylene glycol. PMID:26904700

  1. Fabrication of source and drain regions of self-aligned ZrInZnO thin-film transistors using a solution of tin and poly(propylene carbonate)

    NASA Astrophysics Data System (ADS)

    Thi Cam Tu, Huynh; Inoue, Satoshi; Nishioka, Kiyoshi; Fujimoto, Nobutaka; Karashima, Shuichi; Shimoda, Tatsuya

    2015-10-01

    In this paper, we report a novel doping method based on a solution process to fabricate source and drain regions of a self-aligned ZrInZnO thin-film transistor (TFT). A solution of Sn compound mixed with poly(propylene carbonate) (PPC) was used to allow Sn to be diffused into ZrInZnO source and drain regions. The resistivity of the obtained Sn-doped ZrInZnO was reduced dramatically from 4 × 103 to 1.8 × 10-2 Ω cm. The self-aligned ZrInZnO TFT exhibited a mobility of 20 cm2 V-1 s-1, a threshold voltage of 1 V, a subthreshold swing of 0.2 V/decade, and an ON/OFF ratio of 7. These results indicate that the solution-based doping could provide an alternative way to substitute the ion implantation or plasma treatment which are conducted under vacuum for fabrication of the self-aligned oxide semiconductor TFT.

  2. Final report on the safety assessment of PEG-25 propylene glycol stearate, PEG-75 propylene glycol stearate, PEG-120 propylene glycol stearate, PEG-10 propylene glycol, PEG-8 propylene glycol cocoate, and PEG-55 propylene glycol oleate.

    PubMed

    Johnson, W

    2001-01-01

    The ingredients considered in this safety assessment are polyethylene glycol ethers of either propylene glycol itself, propylene glycol stearate, propylene glycol oleate, or propylene glycol cocoate. They function in cosmetic formulations as surfactant--cleansing agents; surfactant-solubilizing agents; surfactant--emulsifying agents; skin conditioning agents--humectant; skin-conditioning agents--emollient; and solvents. Those in current use are used in only a small number of cosmetic formulations. Some are not currently used. Polyethylene Glycol (PEG) Propylene Glycol Cocoates and PEG Propylene Glycol Oleates are produced by the esterification of polyoxyalkyl alcohols with lauric acid and oleic acid, respectively. Although there is no information available on the method of manufacture of the other polymers, information was available describing impurities, including ethylene oxide (maximum 1 ppm), 1,4-dioxane (maximum 5 ppm), polycyclic aromatic compounds (maximum 1 ppm), and heavy metals-lead, iron, cobalt, nickel, cadmium, and arsenic included (maximum 10 ppm combined). In an acute oral toxicity study, PEG-25 Propylene Glycol Stearate was not toxic. An antiperspirant product containing 2.0% PEG-25 Propylene Glycol Stearate was nonirritating to mildly irritating to the eyes of rabbits. This product was also practically nonirritating to the skin of rabbits in single-insult occlusive patch tests. In a guinea pig sensitization test, PEG-25 Propylene Glycol Stearate was classified as nonallergenic at challenge concentrations of 25% and 50% in petrolatum. PEG-25 Propylene Glycol Stearate and PEG-55 Propylene Glycol Oleate were negative in clinical patch tests. Based on the available data, it was concluded that these ingredients are safe as used (concentrations no greater than 10%) in cosmetic formulations. Based on evidence of sensitization and nephrotoxicity in burn patients treated with a PEG-based antimicrobial preparation, the ingredients included in this review

  3. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Propylene glycol alginate. 172.858 Section 172.858... Propylene glycol alginate. The food additive propylene glycol alginate (CAS Reg. No. 9005-37-2) may be used... the act: (1) The name of the additive, “propylene glycol alginate” or “propylene glycol ester...

  4. Evaluation of activated sludge for biodegradation of propylene glycol as an aircraft deicing fluid.

    PubMed

    Delorit, Justin D; Racz, LeeAnn

    2014-04-01

    Aircraft deicing fluid used at airport facilities is often collected for treatment or disposal in order to prevent serious ecological threats to nearby surface waters. This study investigated lab scale degradation of propylene glycol, the active ingredient in a common aircraft deicing fluid, by way of a laboratory-scale sequencing batch reactor containing municipal waste water treatment facility activated sludge performing simultaneous organic carbon oxidation and nitrification. The ability of activated sludge to remove propylene glycol was evaluated by studying the biodegradation and sorption characteristics of propylene glycol in an activated sludge medium. The results indicate sorption may play a role in the fate of propylene glycol in AS, and the heterotrophic bacteria readily degrade this compound. Therefore, a field deployable bioreactor may be appropriate for use in flight line applications. PMID:24851333

  5. Propylene on Pt(111)I. Characterization of surface species by infra-red spectroscopy

    NASA Astrophysics Data System (ADS)

    Zaera, Francisco; Chrysostomou, Demetrius

    2000-06-01

    The adsorption of propylene on Pt(111) single-crystal surfaces was characterized by reflection-absorption infra-red spectroscopy (RAIRS). The uptake of propylene on the surface at 90 K results in the development of at least four adsorption species as a function of coverage. Significant rehybridization of the CC double bond of propylene takes place at low coverages, so the molecule primarily interacts with the metal via two σ metalcarbon bonds. Below half-saturation, the molecule mainly bonds through the central carbon atom, but at higher coverage, the CC bond becomes flat, and the terminal methyl group tilts towards a more vertical orientation. Further dosing of propylene after saturation of the di-σ state leads to the build-up of a flat π-bonded second layer. Ultimately, a layer of condensed propylene could be grown on the surface under the vacuum conditions of the experiment as long as the temperature was kept below 80 K. Annealing of the low-temperature propylene-saturated Pt(111) surface first induces the desorption of the weakly held π species, and later, between 230 and 250 K, to the dehydrogenation and rearrangement of the remaining di-σ species to propylidyne (Pt 3CCH 2CH 3). The details of the conversion of propylene to propylidyne change somewhat with the conditions under which this transformation is carried out, and appear to involve a stable and identifiable intermediate [2-propyl, CH 3CH(Pt)CH 3, and/or propylidene, Pt 2CHCH 2CH 3]. Propylene π-bonding is also possible on propylidyne-saturated Pt(111) surfaces under vacuum.

  6. Pyrolysis and Combustion of Acetonitrile (CH{sub 3}CN)

    SciTech Connect

    Britt, P.F.

    2002-05-22

    Acetonitrile (CH{sub 3}CN) is formed from the thermal decomposition of a variety of cyclic, noncyclic, and polymeric nitrogen-containing compounds such as pyrrole and polyacrylonitrile. The pyrolysis and combustion of acetonitrile have been studied over the past 30 years to gain a more detailed understanding of the complex mechanisms involved in the release of nitrogen-containing compounds such as hydrogen cyanide (HCN) in fires and nitrogen oxides (NOx) in coal combustion. This report reviews the literature on the formation of HCN and NOx from the pyrolysis and combustion of acetonitrile and discusses the possible products found in an acetonitrile fire.

  7. Ruminal fermentation of propylene glycol and glycerol.

    PubMed

    Trabue, Steven; Scoggin, Kenwood; Tjandrakusuma, Siska; Rasmussen, Mark A; Reilly, Peter J

    2007-08-22

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h, all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in decreasing order, all increased with incubation time. Addition of any of the three substrates somewhat decreased acetate formation, while addition of either propylene glycol increased propionate formation but decreased that of butyrate. R- and S-propylene glycol did not differ significantly in either their rates of disappearance or the products formed when they were added to the fermentation medium. Fermentations of rumen fluid containing propylene glycol emitted the sulfur-containing gases 1-propanethiol, 1-(methylthio)propane, methylthiirane, 2,4-dimethylthiophene, 1-(methylthio)-1-propanethiol, dipropyl disulfide, 1-(propylthio)-1-propanethiol, dipropyl trisulfide, 3,5-diethyl-1,2,4-trithiolane, 2-ethyl-1,3-dithiane, and 2,4,6-triethyl-1,3,5-trithiane. Metabolic pathways that yield each of these gases are proposed. The sulfur-containing gases produced during propylene glycol fermentation in the rumen may contribute to the toxic effects seen in cattle when high doses are administered for therapeutic purposes. PMID:17655323

  8. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Propylene glycol alginate. 172.858 Section 172.858... CONSUMPTION Multipurpose Additives § 172.858 Propylene glycol alginate. The food additive propylene glycol... information required by the act: (1) The name of the additive, “propylene glycol alginate” or...

  9. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Propylene glycol alginate. 172.858 Section 172.858... CONSUMPTION Multipurpose Additives § 172.858 Propylene glycol alginate. The food additive propylene glycol... information required by the act: (1) The name of the additive, “propylene glycol alginate” or...

  10. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Propylene glycol alginate. 172.858 Section 172.858... CONSUMPTION Multipurpose Additives § 172.858 Propylene glycol alginate. The food additive propylene glycol... information required by the act: (1) The name of the additive, “propylene glycol alginate” or...

  11. Cardiovascular effects of intravenous administration of propylene glycol and of oxytetracycline in propylene glycol in calves.

    PubMed

    Gross, D R; Kitzman, J V; Adams, H R

    1979-06-01

    Comparisons were made of the acute cardiovascular effects of oxytetracycline, oxytetracycline in propylene glycol, and propylene glycol alone given to conscious dairy calves. The calves were chronically instrumented with intravascular catheters and electromagnetic flowmeter transducers in and on the pulmonary and renal arteries. Injection (IV) of aqueous preparations of oxytetracycline produced no statistically significant (P greater than 0.05) cardiocirculatory changes in these calves. Oxytetracycline in propylene glycol and propylene glycol alone both produced transient (1 to 4 minute) periods of cardiovascular depression characterized by cardiac asystole, systemic hypotension, and decreased pulmonary and renal arterial blood flow. The two preparations, in equivalent doses and volumes, produced statistically similar hemodynamic changes in the calves. The data from this study support the conclusion that the monitored cardiovascular effects of the commercially available oxytetracycline in propylene glycol in the intact, awake calves were due to the solvent propylene glycol. This conclusion is consistent with reports of other injectable products containing the same solvent. PMID:475130

  12. Low temperature specific heat of propylene glycol

    SciTech Connect

    Zhu, Da-Ming; Chen, Huiwei

    1997-01-01

    The specific heat of propylene glycol has been measured at temperatures from 0.1 K to 6 K. The magnitude and the temperature dependence of the specific heat are similar to that found in other fragile glasses.

  13. Increased Silver Activity for Direct Propylene Epoxidation via Subnanometer Size Effects

    SciTech Connect

    Lei, Y.; Mehmood, Faisal; Lee, Sang Soo; Greeley, Jeffrey P.; Lee, Byeongdu; Seifert, Soenke; Winans, R. E.; Elam, J. W.; Meyer, R. J.; Redfern, Paul C.; Teschner, D.; Schlogl, Robert; Pellin, M. J.; Curtiss, Larry A.; Vajda, S.

    2010-04-09

    Production of the industrial chemical propylene oxide is energy-intensive and environmentally unfriendly. Catalysts based on bulk silver surfaces with direct propylene epoxidation by molecular oxygen have not resolved these problems because of substantial formation of carbon dioxide. We found that unpromoted, size-selected Ag3 clusters and ~3.5-nanometer Ag nanoparticles on alumina supports can catalyze this reaction with only a negligible amount of carbon dioxide formation and with high activity at low temperatures. Density functional calculations show that, relative to extended silver surfaces, oxidized silver trimers are more active and selective for epoxidation because of the open-shell nature of their electronic structure. The results suggest that new architectures based on ultrasmall silver particles may provide highly efficient catalysts for propylene epoxidation.

  14. Preparation of propylene homopolymers or copolymers

    SciTech Connect

    Rau, W.; Hennenberger, P.; Klamann, H.

    1984-04-10

    The disclosure is directed to an improvement in the gas phase polymerization of propylene using a Ziegler-Natta catalyst in the presence of hydrogen wherein the gaseous propylene is withdrawn from the reactor, cooled and condensed and returned as a liquid to the reactor in order to regulate the polymerization temperature. The amount of the gaseous phase in the condenser-cooler-accumulator system is kept constant by regulating the amount of gaseous phase returned to the reactor.

  15. Intermolecular forces in acetonitrile + ethanol binary liquid mixtures

    NASA Astrophysics Data System (ADS)

    Elangovan, A.; Shanmugam, R.; Arivazhagan, G.; Mahendraprabu, A.; Karthick, N. K.

    2015-10-01

    FTIR spectral measurements have been carried out on the binary mixtures of acetonitrile with ethanol at 1:0 (acetonitrile:ethanol), 1:1, 1:2, 1:3 and 0:1 at room temperature. DFT and isosurface calculations have been performed. The acetonitrile + ethanol binary mixtures consist of 1:1, 1:2, 1:3 and 1:4 complexes formed through both the red and blue shifting H-bonds. Inter as well as intra molecular forces are found to exist in 1:3 and 1:4 complexes.

  16. A facile route to synthesize endurable mesopore containing ZSM-5 catalyst for methanol to propylene reaction.

    PubMed

    Sun, Chao; Du, Junming; Liu, Jian; Yang, Yisu; Ren, Nan; Shen, Wei; Xu, Hualong; Tang, Yi

    2010-04-21

    A novel route is proposed for the preparation of mesopore containing zeolite ZSM-5 via in situ hydrothermal treatment of a solution containing alkali-dissolved SBA-15 containing carbonized surfactant P123 in the mesopores; it exhibited prominent stability enhancement for methanol to propylene reaction. PMID:20461876

  17. Low temperature properties of acetonitrile confined in MCM-41.

    PubMed

    Kittaka, Shigeharu; Iwashita, Takafumi; Serizawa, Akihiro; Kranishi, Miki; Takahara, Shuichi; Kuroda, Yasushige; Mori, Toshinori; Yamaguchi, Toshio

    2005-12-15

    The effect of confinement on the phase changes and dynamics of acetonitrile in mesoporous MCM-41 was studied by use of adsorption, FT-IR, DSC, and quasi-elastic neutron scattering (QENS) measurements. Acetonitrile molecules in a monolayer interact strongly with surface hydroxyls to be registered and perturb the triple bond in the C[triple bond]N group. Adsorbed molecules above the monolayer through to the central part of the cylindrical pores are capillary condensed molecules (cc-acetonitrile), but they do not show the hysteresis loop in adsorption-desorption isotherms, i.e., second order capillary condensation. FT-IR measurements indicated that the condensed phase is very similar to the bulk liquid. The cc-acetonitrile freezes at temperatures that depend on the pore size of the MCM-41 down to 29.1 A (C14), below which it is not frozen. In addition, phase changes between alpha-type and beta-type acetonitriles were observed below the melting points. Application of the Gibbs-Thomson equation, assuming the unfrozen layer thickness to be 0.7 nm, gave the interface free energy differences between the interfaces, i.e., Deltagamma(l/alpha) = 22.4 mJ m(-2) for the liquid/pore surface (ps) and alpha-type/ps, and Deltagamma(alpha/beta) = 3.17 mJ m(-2) for alpha-type/ps and beta-type/ps, respectively. QENS experiments substantiate the differing behaviors of monolayer acetonitrile and cc-acetonitrile. The monolayer acetonitrile molecules are anchored so as not to translate. The two Lorentzian analysis of QENS spectra for cc-acetonitriles showed translational motion but markedly slowed. However, the activation energy for cc-acetonitrile in MCM-41 (C18) is 7.0 kJ mol(-1) compared to the bulk value of 12.7 kJ mol(-1). The relaxation times for tumbling rotational diffusion of cc-acetonitrile are similar to bulk values. PMID:16375278

  18. Oxidative dehydrogenation dimerization of propylene over bismuth oxide: kinetic and mechanistic studies

    SciTech Connect

    White, M.G.; Hightower, J.W.

    1983-07-01

    Classical kinetic experiments together with pulse microreactor studies involving deuterium and carbon-13-labeled isotopic tracers were used to investigate the oxidative dehydrogenation dimerization (OXDD) of propylene to 1,5-hexadiene and benzene over bismuth oxide between 748 and 898/sup 0/K. The kinetic data, which indicated that the OXDD reaction is of variable order with respect to oxygen and propylene concentrations, could be fit to rate equations based on either the Langmuir-Hinshelwood model or the Mars-van Krevelen model, although the former gave more linear Arrhenius plots. A significant kinetic isotope effect (k/sub H//k/sub D/ = 1.7 at 873/sup 0/K) shows that the rate-limiting step for the OXDD reaction involves C-H cleavage, and there is only a small amount of H/D scrambling among reactant and product molecules. Analysis of liquid products by infrared spectroscopy indicated that both 1,5-hexadiene and 1,3-cyclohexadiene are stable reaction intermediates; microreactor results involving unlabeled propylene, 1,5-hexadiene, 1,3-cyclohexadiene, and 1,4-cyclohexadiene as reactants confirmed the infrared findings. Pulse microreactor experiments with /sup 13/C-labeled propylene clearly showed that deep oxidation (complete combustion) occurs via a consecutive-parallel network involving the partially oxidized intermediates as well as the starting propylene. Changes in the particle size do not alter the overall activity, although larger particles have lower selectivities for C/sub 6/ products than do smaller particles.

  19. Inhalation developmental toxicology studies: Acetonitrile in rats. Final report

    SciTech Connect

    Mast, T.J.; Weigel, R.J.; Westerberg, R.B.; Boyd, P.J.; Hayden, B.K.; Evanoff, J.J.; Rommereim, R.L.

    1994-02-01

    The potential for acetonitrile to cause developmental toxicity was assessed in Sprague-Dawley rats exposed to 0, 100, 400, or 1200 ppM acetonitrile, 6 hours/day, 7 days/week. Exposure of rats to these concentrations of acetonitrile resulted in mortality in the 1200 ppM group (2/33 pregnant females; 1/10 non-pregnant females). However, there were no treatment-related effects upon body weights or reproduction indices at any exposure level, nor was there a significant increase in the incidence of fetal malformations or variations. The only effect observed in the fetuses was a slight, but not statiscally significant, exposure-correlated increase in the incidence of supernumerary ribs. Determination of acetonitrile and cyanide concentrations in maternal rat blood showed that acetonitrile concentration in the blood increased with exposure concentration for all exposed maternal rats. Detectable amounts of cyanide in the blood were found only in the rats exposed to 1200 ppM acetonitrile ({approximately}2 {mu}g cyanide/g of blood).

  20. 76 FR 79146 - Propylene Oxide; Proposed Tolerance Actions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-21

    ...EPA is proposing to establish the tree nut crop group tolerance and separate tolerances on pistachio and pine nuts for both the fumigant propylene oxide and the reaction product from the use of propylene oxide, known as propylene chlorohydrin, to cover all registered uses on raw and processed nuts. Also, in accordance with current Agency practice, EPA is proposing minor revisions to tolerance......

  1. A kinetic study on the bioremediation of sodium cyanide and acetonitrile by free and immobilized cells of pseudomonas putida

    SciTech Connect

    Chapatwala, K.D.; Babu, G.R.V.; Armstead, E.R.

    1995-12-31

    Pseudomonas putida capable of utilizing organic nitrile (acetonitrile) and inorganic cyanide (sodium cyanide) as the sole source of carbon and nitrogen was isolated from contaminated industrial sites and waste water. The bacterium possesses nitrile aminohydrolase (EC 3.5.5.1) and amidase (EC 3.5.1.4), which are involved in the transformation of cyanides and nitrites into ammonia and CO{sub 2} through the formation of amide as an intermediate. Both of the enzymes have a high selectivity and affinity toward the {sup -}CN group. The rate of degradation of acetonitrile and sodium cyanide to ammonia and CO{sub 2} by the calcium-alginate immobilized cells of P. putida was studied. The rate of reaction during the biodegradation of acetonitrile and sodium cyanide, and the substrate- and product-dependent kinetics of these toxic compounds were studied using free and immobilized cells of P. putida and modeled using a simple Michaelis-Menten equation.

  2. 21 CFR 184.1666 - Propylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Propylene glycol. 184.1666 Section 184.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  3. 21 CFR 184.1666 - Propylene glycol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Propylene glycol. 184.1666 Section 184.1666 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  4. Conversion of 1,2-Propylene Glycol on Rutile TiO2(110)

    SciTech Connect

    Chen, Long; Li, Zhenjun; Smith, R. Scott; Kay, Bruce D.; Dohnalek, Zdenek

    2014-07-17

    We have studied the reactions of 1,2-propylene glycol (1,2-PG), DOCH(CH3)CH2OD, on partially reduced, hydroxylated and oxidized TiO2(110) surfaces using temperature programmed desorption. On reduced TiO2(110), propylene, propanal, and acetone are identified as primary carbon-containing products. While the propylene formation channel dominates at low 1,2-PG coverages, all of the above-mentioned products are observed at high coverages. The carbon-containing products are accompanied by the formation of D2O and D2. The observation of only deuterated products shows that the source of hydrogen (D) is from the 1,2-PG hydroxyls. The role of bridging oxygen vacancy (VO) sites was further investigated by titrating them via hydroxylation and oxidation. The results show that hydroxylation does not change the reactivity because the VO sites are regenerated at 500 K, which is a temperature lower than the 1,2-PG product formation temperature. In contrast, surface oxidation causes significant changes in the product distribution, with increased acetone and propanal formation and decreased propylene formation. Additionally D2 is completely eliminated as an observed product at the expense of D2O formation.

  5. Laser synthesis and spectroscopy of acetonitrile/silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Akin, S. T.; Liu, X.; Duncan, M. A.

    2015-11-01

    Silver nanoparticles with acetonitrile ligands are produced in a laser ablation flow reactor. Excimer laser ablation produces gas phase metal clusters which are thermalized with helium or argon collisions in the flowtube, and reactions with acetonitrile vapor coordinate this ligand to the particle surface. The gaseous mixture is captured in a cryogenic trap; warming produces a solution of excess ligand and coated particles. TEM images reveal particle sizes of 10-30 nm diameter. UV-vis absorption and fluorescence spectra are compared to those of standard silver nanoparticles with surfactant coatings. Deep-UV ligand absorption is strongly enhanced by nanoparticle adsorption.

  6. Reaction Mechanism for Direct Propylene Epoxidation by Alumina-Supported Silver Aggregates. The Role of the Particle / Support Interface

    SciTech Connect

    Cheng, Lei; Yin, Chunrong; Mehmood, Faisal; Liu, Bin; Greeley, Jeffrey P.; Lee, Sungsik; Lee, Byeongdu; Seifert, Soenke; Winans, R. E.; Teschner, D.; Schlogl, Robert; Vajda, S.; Curtiss, Larry A.

    2013-11-21

    Sub-nanometer Ag aggregates on alumina supports have been found to be active toward direct propylene epoxidation to propylene oxide by molecular oxygen at low temperatures, with a negligible amount of carbon dioxide formation (Science 328, p. 224, 2010). In this work, we computationally and experimentally investigate the origin of the high reactivity of the sub-nanometer Ag aggregates. Computationally, we study O2 dissociation and propylene epoxidation on unsupported Ag19 and Ag20 clusters, as well as alumina-supported Ag19. The O2 dissociation and propylene epoxidation apparent barriers at the interface between the Ag aggregate and the alumina support are calculated to be 0.2 and 0.2~0.4 eV, respectively. These barriers are somewhat lower than those on sites away from the interface. The mechanism at the interface is similar to what was previously found for the silver trimer on alumina and can account for the high activity observed for the direct oxidation of propylene on the Ag aggregates. The barriers for oxygen dissociation on these model systems both at the interface and on the surfaces are small compared to crystalline surfaces, indicating that availability of oxygen will not be a rate limiting step for the aggregates, as in the case of the crystalline surfaces. Experimentally, we investigate Ultrananocrystalline Diamond (UNCD)-supported silver aggregates under reactive conditions of propylene partial oxidation. The UNCD-supported Ag clusters are found to be not measurably active toward propylene oxidation, in contrast to the alumina supported Ag clusters. This suggests that the lack of metal-oxide interfacial sites of the Ag-UNCD catalyst, limits the epoxidation catalytic activity. This combined computational and experimental study shows the importance of the metal-oxide interface as well as the non-crystalline nature of the alumina-supported sub-nanometer Ag aggregate catalysts for propylene epoxidation.

  7. Silicate stabilization studies in propylene glycol

    SciTech Connect

    Schwartz, S.A.

    1999-08-01

    In most North American and many European coolant formulations, the corrosion inhibition of heat-rejecting aluminum surfaces is provided by alkali metal silicates. But, their tendency towards polymerization, leading to gelation and/or precipitation, can reduce the effectiveness of a coolant. This paper presents the results of experiments which illustrate formulation-dependent behavior of inorganic silicate in propylene glycol compositions. Specific examples of the effects of glycol matrix, stabilizer type, and hard water on silicate stabilization are provided.

  8. Synthesis of propylene oxide from propylene and hydrogen peroxide catalyzed by titanium silicalite

    SciTech Connect

    Clerici, M.G.; Bellussi, G. ); Romano, U. )

    1991-05-01

    The epoxidation of propylene with hydrogen peroxide in the liquid phase, in the presence of titanium silicalite catalyst (TS-1), is described. The best solvents are methonol and methanol/water mixtures. The temperature is normally between room temperature and 60{degree}C. Under these conditions, reaction rates are fast, yields on H{sub 2}O{sub 2} are quantitative, and selectivity to propylene oxide is very high. Propylene glycol and its monomethyl ethers and trace amounts of formaldehyde are the only by-products formed. Selectivity is further improved and the hydrolysis of the epoxide is almost suppressed when the residual acidity of the catalyst is completely neutralized. The activity of spent catalyst is recovered by calcining at 550{degree}C or, more simply, by washing with solvents. Complete activity recovery shows that Ti is not removed from the crystalline framework during the epoxidation reactions.

  9. Reaction of CO2 with propylene oxide and styrene oxide catalyzed by a chromium(III) amine-bis(phenolate) complex.

    PubMed

    Dean, Rebecca K; Devaine-Pressing, Katalin; Dawe, Louise N; Kozak, Christopher M

    2013-07-01

    A diamine-bis(phenolate) chromium(III) complex, {CrCl[O2NN'](BuBu)}2 catalyzes the copolymerization of propylene oxide with carbon dioxide. The synthesis of this metal complex is straightforward and it can be obtained in high yields. This catalyst incorporates a tripodal amine-bis(phenolate) ligand, which differs from the salen or salan ligands typically used with Cr and Co complexes that have been employed as catalysts for the synthesis of such polycarbonates. The catalyst reported herein yields low molecular weight polymers with narrow polydispersities when the reaction is performed at room temperature. Performing the reaction at elevated temperatures causes the selective synthesis of propylene carbonate. The copolymerization activity for propylene oxide and carbon dioxide, as well as the coupling of carbon dioxide and styrene oxide to give styrene carbonate are presented. PMID:23192332

  10. Dipolar ordering and relaxations in acetonitrile-β-hydroquinone clathrate

    NASA Astrophysics Data System (ADS)

    Rheinstädter, M. C.; Kityk, A. V.; Klöpperpieper, A.; Knorr, K.

    2002-08-01

    Single crystals of this clathrate have been studied by measurements of the frequency and temperature dependent dielectric permittivity as well as with polarization-electric field cycles and x-ray diffraction. The dipole moments of the acetonitrile guest molecules form Ising chains that are coupled by the electric dipole-dipole interaction and that are arranged in a triangular array. At 345 K a phase transition from a partially disordered antiferroelectric to a ferrielectric arrangement is observed.

  11. Photophysics of Diphenylbutadiynes in Water, Acetonitrile-Water, and Acetonitrile Solvent Systems: Application to Single Component White Light Emission.

    PubMed

    Pati, Avik Kumar; Jana, Rounak; Gharpure, Santosh J; Mishra, Ashok K

    2016-07-28

    Diacetylenes have been the subject of current research because of their interesting optoelectronic properties. Herein, we report that substituted diphenylbutadiynes exhibit locally excited (LE) and excimer emissions in water and multiple emissions from the LE, excimer, and intramolecular charge transfer (ICT) states in acetonitrile-water solvent systems. The LE, excimer, and ICT emissions are clearly distinguishable for a diphenylbutadiynyl derivative with push (-NMe2)-pull (-CN) substituents and those are closely overlapped for non-push-pull analogues. In neat acetonitrile, the excimer emission disappears and the LE and ICT emissions predominate. In the case of the push (-NMe2)-pull (-CN) diphenylbutadiyne, the intensity of the ICT emission increases with increasing the fluorophore concentration. This suggests that the ICT emission accompanies with intermolecular CT emission which is of exciplex type. As the LE and exciplex emissions of the push-pull diphenylbutadiyne together cover the visible region (400-700 nm) in acetonitrile, a control of the fluorophore concentration makes the relative intensities of the LE and exciplex emissions such that pure white light emission is achieved. The white light emission is not observed in those diphenylbutadiynyl analogues in which the peripheral substituents of the phenyl rings do not possess strong push-pull character. PMID:27379734

  12. 76 FR 17611 - Propylene Oxide; Proposed Pesticide Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-30

    ... Register of September 24, 2008 (73 FR 54954) (FRL-8382-2). EPA took the opposite action--amending the..., 2008 (73 FR 31788, 317990) (FRL-8363-9). The Reregistration Eligibility Decision for propylene oxide..., Reregistration Eligibility Decision for Propylene Oxide, in the Federal Register of August 9, 2006 (71 FR...

  13. Unexpected superoxide dismutase antioxidant activity of ferric chloride in acetonitrile.

    PubMed

    Foti, Mario C; Ingold, K U

    2003-11-14

    The azobis(isobutyronitrile)-initiated autoxidation of gamma-terpinene in acetonitrile at 50 degrees C yields only p-cymene and hydrogen peroxide (1:1) in a chain reaction carried by the hydroperoxyl radical, HOO. (Foti, M. C.; Ingold, K. U. J. Agric. Food Chem. 2003, 51, 2758-2765). This reaction is retarded by very low (microM) concentrations of FeCl(3) and CuCl(2). The kinetics of the FeCl(3)-inhibited autoxidation are consistent with chain-termination via the following: Fe(3+) + HOO. <==>[Fe(IV)-OOH](3+) and [Fe(IV)-OOH](3+) + HOO. --> Fe(3+) + H2O2 + O2. Thus, FeCl(3) in acetonitrile can be regarded as a very effective (and very simple) superoxide dismutase. The kinetics of the CuCl(2)-inhibited autoxidation indicate that chain transfer occurs and becomes more and more important as the reaction proceeds, i.e., the inhibition is replaced by autocatalysis. These kinetics are consistent withreduction of Cu2+ to Cu+ by HOO. and then the reoxidation of Cu+ to Cu2+ by both HOO.and the H2O2 product. The latter reaction yields HO. radicals which continue the chain. PMID:14604404

  14. Novel polymer composites from waste ethylene-propylene-diene-monomer rubber by supercritical CO2 foaming technology.

    PubMed

    Jeong, Keuk Min; Hong, Yeo Joo; Saha, Prosenjit; Park, Seong Ho; Kim, Jin Kuk

    2014-11-01

    In this study, a composite has been prepared by mixing waste rubber, such as ethylene-propylene-diene-monomer and low-density poly ethylene foaming, with supercritical carbon dioxide. In order to optimise the foaming process of the waste ethylene-propylene-diene-monomer-low-density poly ethylene composite, the variations of pressure and temperature on the foamed Microcell formation were studied. As indicated in scanning electron microscope photographs, the most uniform microcellular pattern was found at 200 bar and 100 °C using 30% by weight of waste ethylene-propylene-diene-monomer. Carbon dioxide could not be dissolved uniformly during foaming owing to extensive cross-linking of the waste ethylene-propylene-diene-monomer used for the composite. As a result the presence of un-uniform microcells after foaming were observed in the composite matrix to impart inferior mechanical properties of the composite. This problem was solved with uniform foaming by increasing the cross-link density of low-density poly ethylene using 1.5 parts per hundred dicumyl peroxide that enhances composite tensile and compressive strength up to 57% and 15%, respectively. The composite has the potential to be used as a foaming mat for artificial turf. PMID:25106537

  15. Growth of Single-Layer Graphene on Pt(111) by Thermal Decomposition of Propylene

    NASA Astrophysics Data System (ADS)

    Hodges, Gregory; Geisler, Heike; Ventrice, Carl

    2009-10-01

    Graphene, which is a one-atom-thick layer of sp^2-bonded carbon, has sparked keen interest within the scientific community because it is predicted to have a wide range of unique properties. In particular, it has one of the highest known mobilities of all the semiconducting materials. Since its discovery in 2004, there have been several studies of the growth of graphene by various techniques. We have performed studies on the growth of graphene on the catalytically active Pt(111) surface by thermal decomposition of propylene in an ultra-high vacuum (UHV) chamber. Two methods have been used: deposition of a monolayer of propylene followed by annealing in UHV and growth of graphene in an atmosphere of 10-6 Torr of propylene at 500 ^oC. The crystal structure of the graphene films was monitored using low energy electron diffraction (LEED). In addition, we are currently performing high resolution electron energy loss spectroscopy (HREELS) measurements of the electronic structure of the graphene films.

  16. Natural and enhanced biodegradation of propylene glycol in airport soil.

    PubMed

    Toscano, Giuseppe; Colarieti, M Letizia; Anton, Attila; Greco, Guido; Biró, Borbála

    2014-01-01

    Aircraft de-icing fluids (ADF) are a source of water and soil pollution in airport sites. Propylene glycol (PG) is a main component in several commercial formulations of ADFs. Even though PG is biodegradable in soil, seasonal overloads may result in occasional groundwater contamination. Feasibility studies for the biostimulation of PG degradation in soil have been carried out in soil slurries, soil microcosms and enrichment cultures with and without the addition of nutrients (N and P sources, oligoelements), alternative electron acceptors (nitrate, oxygen releasing compounds) and adsorbents (activated carbon). Soil samples have been taken from the contaminated area of Gardermoen Airport Oslo. Under aerobic conditions and in the absence of added nutrients, no or scarce biomass growth is observed and PG degradation occurs by maintenance metabolism at constant removal rate by the original population of PG degraders. With the addition of nutrient, biomass exponential growth enhances aerobic PG degradation also at low temperatures (4 ° C) that occur at the high season of snowmelt. Anaerobic PG degradation without added nutrients still proceeds at constant rate (i.e. no biomass growth) and gives rise to reduced fermentation product (propionic acid, reduced Fe and Mn, methane). The addition of nitrate does not promote biomass growth but allows full PG mineralization without reduced by-products. Further exploitation on the field is necessary to fully evaluate the effect of oxygen releasing compounds and adsorbents. PMID:23828729

  17. Study of the mechanism of acetonitrile stacking and its application for directly combining liquid-phase microextraction with micellar electrokinetic chromatography.

    PubMed

    Sun, Jingru; Feng, Jing; Shi, Ludi; Liu, Laping; He, Hui; Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2016-08-26

    Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260-791. Limits of qualification ranged from 5.5 to 16.0ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl(-) ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. PMID:27451260

  18. Another glimpse over the salting-out assisted liquid-liquid extraction in acetonitrile/water mixtures.

    PubMed

    Valente, Inês Maria; Gonçalves, Luís Moreira; Rodrigues, José António

    2013-09-20

    The use of the salting-out effect in analytical chemistry is very diverse and can be applied to increase the volatility of the analytes in headspace extractions, to cause the precipitation of proteins in biological samples or to improve the recoveries in liquid-liquid extractions. In the latter, the salting-out process can be used to create a phase separation between water-miscible organic solvents and water. Salting-out assisted liquid-liquid extraction (SALLE) is an advantageous sample preparation technique aiming HPLC-UV analysis when developing analytical methodologies. In fact, some new extraction methodologies like QuEChERS include the SALLE concept. This manuscript discusses another point of view over SALLE with particular emphasis over acetonitrile-water mixtures for HPLC-UV analysis; the influence of the salting-out agents, their concentration and the water-acetonitrile volume ratios were the studied parameters. α-dicarbonyl compounds and beer were used as test analytes and test samples, respectively. The influence of the studied parameters was characterized by the obtained phase separation volume ratio and the fraction of α-dicarbonyls extracted to the acetonitrile phase. Results allowed the distribution of salts within three groups according to the phase separation and their extractability: (1) chlorides and acetates, (2) carbonates and sulfates and (3) magnesium sulfate; of all tested salts, sodium chloride had the highest influence on the α-dicarbonyls fraction extracted. PMID:23958692

  19. Conversion of Dinitrogen into Acetonitrile under Ambient Conditions.

    PubMed

    Klopsch, Isabel; Kinauer, Markus; Finger, Markus; Würtele, Christian; Schneider, Sven

    2016-04-01

    About 20% of the ammonia production is used as the chemical feedstock for nitrogen-containing chemicals. However, while synthetic nitrogen fixation at ambient conditions has had some groundbreaking contributions in recent years, progress for the direct conversion of N2 into organic products remains limited and catalytic reactions are unknown. Herein, the rhenium-mediated synthesis of acetonitrile using dinitrogen and ethyl triflate is presented. A synthetic cycle in three reaction steps with high individual isolated yields and recovery of the rhenium pincer starting complex is shown. The cycle comprises alkylation of a nitride that arises from N2 splitting and subsequent imido ligand centered oxidation to nitrile via a 1-azavinylidene (ketimido) intermediate. Different synthetic strategies for intra- and intermolecular imido ligand oxidation and associated metal reduction were evaluated that rely on simple proton, electron, and hydrogen-atom transfer steps. PMID:26948973

  20. Ultrafast vibrational energy flow in water monomers in acetonitrile

    NASA Astrophysics Data System (ADS)

    Dahms, Fabian; Costard, Rene; Nibbering, Erik T. J.; Elsaesser, Thomas

    2016-05-01

    Vibrational relaxation of the OH stretching and bending modes of water monomers in acetonitrile is studied by two-color pump-probe experiments in a frequency range from 1400 to 3800 cm-1. Measurements with resonant infrared excitation reveal vibrational lifetimes of 6.4 ± 1.0 ps of the OH stretching modes and 4.0 ± 0.5 ps of the OH bending mode. After OH stretching excitation, the OH bending mode shows an instantaneous response, a hallmark of the anharmonic coupling of stretching and bending modes, and a delayed population buildup by relaxation of the stretching via the bending mode. The relaxation steps are discussed within the framework of current theoretical pictures of water's vibrational relaxation.

  1. Capacitance of edge plane of pyrolytic graphite in acetonitrile solutions

    SciTech Connect

    Minick, S.K.; Ishida, Takanobu.

    1991-05-01

    The capacitance of the edge plane of pyrolytic graphite electrodes, in acetonitrile solutions, is measured by recording the current response to an applied triangular voltage sweep; TVS, and then fitting the current response with an appropriate function, (via a set of adjustable parameters). The pretreatment of the electrodes, the supporting electrolyte concentration used, and the frequency of the input TVS, were all found to affect the measured capacitance. In these experiments, a background current was also seen and the shape of the current output for the TVS; the charging/discharging curve, is shown to correlate with the magnitude of this background current. In addition, the size of the background current was found to have some dependence on the type of electrode pretreatment procedure used. 60 refs., 49 figs., 3 tabs.

  2. 46 CFR 151.50-13 - Propylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-13 Propylene oxide. (a)(1... more than the design pressure of the tank. (d) Filling density shall not exceed 80 percent. (e)(1)...

  3. 46 CFR 151.50-13 - Propylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-13 Propylene oxide. (a)(1... more than the design pressure of the tank. (d) Filling density shall not exceed 80 percent. (e)(1)...

  4. 46 CFR 151.50-13 - Propylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-13 Propylene oxide. (a)(1... more than the design pressure of the tank. (d) Filling density shall not exceed 80 percent. (e)(1)...

  5. 46 CFR 151.50-13 - Propylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-13 Propylene oxide. (a)(1... more than the design pressure of the tank. (d) Filling density shall not exceed 80 percent. (e)(1)...

  6. 46 CFR 151.50-13 - Propylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-13 Propylene oxide. (a)(1... more than the design pressure of the tank. (d) Filling density shall not exceed 80 percent. (e)(1)...

  7. Measurement of diffusion coefficient of propylene glycol in skin tissue

    NASA Astrophysics Data System (ADS)

    Genin, Vadim D.; Bashkatov, Alexey N.; Genina, Elina A.; Tuchin, Valery V.

    2015-03-01

    Optical clearing of the rat skin under the action of propylene glycol was studied ex vivo. It was found that collimated transmittance of skin samples increased, whereas weight and thickness of the samples decreased during propylene glycol penetration in skin tissue. A mechanism of the optical clearing under the action of propylene glycol is discussed. Diffusion coefficient of propylene glycol in skin tissue ex vivo has been estimated as (1.35±0.95)×10-7 cm2/s with the taking into account of kinetics of both weight and thickness of skin samples. The presented results can be useful for enhancement of many methods of laser therapy and optical diagnostics of skin diseases and localization of subcutaneous neoplasms.

  8. PNNL Provides Catalyst for Sustainable Propylene Glycol Production

    SciTech Connect

    Madison, Alison L.; Lund, Eric C.

    2012-02-28

    Submission for annual FLC magazine publication, Technology for Today, featuring technologies transferred by federal labs. Subject: PNNL transfer of Propylene Glycol from Renewable Sources catalytic process to Archer Daniels Midland Company.

  9. An electrochemical investigation of the effect of macrocycle ring size on the binding of di- and trivalent lanthanide cations by 12-crown-4,4-tert-butylbenzo-15-crown-5, and dibenzo-30-crown-10 in propylene carbonate

    SciTech Connect

    Massaux, J.; Desreux, J.F.

    1982-06-02

    The complexation in anhydrous proplene carbonate of the lanthanide ions by various macrocylic polyethers featuring from four to ten oxygen atoms has been investigated by a competitive potentiometric technique with lead(II) or thallium(I) as auxilliary ions. The stability of the complexes appears to depend primarily on the relative sizes of the metal ions and of the internal cavity of each macrocycle. It depends also on the rigidity of the ligands and is influenced by solvation effects. The small ligands 12-crown-4 (1) and 15-crown-5 (2) exhibit a similar behavior: they form 1:2 lanthanide complexes, the stability of which decreases with decreasing ionic radius despite the higher charge density of the metal ions. The presence of an electron-withdrawing phenyl group, as in 4-tert-butylbenzo-15-crown-5 (3), leads to a strong reduction of the stability constants. A maximum stability of 1:1 complexes of 3 is found at Nd(III) while a marked minimum is observed at Gd(III) in the complexation curve of dibenzo-30-crown-10 (5). Divalent samarium and ytterbium are more strongly coordinated than the corresponding trivalent ions by the crown ethers 1-5. The larger divalent ions fit better into the internal cavity of 5 and they form stable 1:2 sandwich complexes with 1 and 3. The properties of the complexes described in the present work are completely different from those reported so far in the case of noncylic ligands.

  10. Bioconversion of cyanide and acetonitrile by a municipal-sewage-derived anaerobic consortium

    SciTech Connect

    Nagle, N.J.; Rivard, C.J.; Mohagheghi, A.; Philippidis, G.

    1995-12-31

    In this study, an anaerobic consortium was examined for its ability to adapt to and degrade the representative organonitriles, cyanide and acetonitrile. Adaptation to cyanide and acetonitrile was achieved by adding increasing levels of cyanide and acetonitrile to the anaerobic consortium, followed by extensive incubation over a 90-day period. The anaerobic consortium adapted most rapidly to the lower concentrations of each substrate and resulted in reductions of 85% and 83% of the cyanide and acetonitrile, respectively, at the 50 mg/L addition level. Increasing the concentration of both cyanide and acetonitrile resulted in reduced bioconversion. Two continuously stirred tank reactors (CSTR) were set up to examine the potential for continuous bioconversion of organonitriles. The anaerobic consortium was adapted to continuous infusion of acetonitrile at an initial concentration of 10 mg/L{center_dot}day in phosphate buffer.

  11. Structure Evolution During Cyclic Deformation of an Elastic Propylene-Based Ethylene-Propylene Copolymer

    SciTech Connect

    Toki,S.; Sics, I.; Burger, C.; Fang, D.; Liu, L.; Hsiao, B.; Datta, S.; Tsou, A.

    2006-01-01

    In-situ structural evolution during uniaxial extension and subsequent retraction of a thermoplastic elastomer (TPE) based on propylene-dominant ethylene-propylene (EP) copolymer was studied. Combined measurements of time-resolved wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) as well as stress-strain curves revealed molecular mechanism responsible for the elastic behavior. During the first cycle of deformation, a fraction of the crystals was destroyed, while the rest was reoriented. At strains larger than 1.0, strain-induced {alpha}-crystals in the lamellar form took place, resulting in the creation of a network with well-oriented lamellae having their normals parallel to the stretching direction. With the increase of strain, more crystals were induced, forming an enhanced network with strain-hardening behavior. During retraction and even after complete relaxation to zero stress, the majority of the strain-induced crystalline network remains in tact as being 'permanent set', where lamellar stacks act as the network points. This strain-induced crystalline network structure is thermally stable at room temperature and is responsible for the elastic behavior during subsequent cyclic deformation, similar to a vulcanized rubber.

  12. Bromidotris(triphenyl­phosphane)silver acetonitrile monosolvate monohydrate

    PubMed Central

    Owczarzak, Anita M.; Kyros, Loukas; Hadjikakou, Sotiris K.; Kubicki, Maciej

    2011-01-01

    In the title compound, [AgBr(C18H15P)3]·C2H3N·H2O, the coordination of the Ag atom is close to ideal tetra­hedral, with the three Ag—P bond lengths almost equal [2.5441 (10), 2.5523 (9) and 2.5647 (10) ° A] and the Ag—Br bond slightly longer [2.7242 (5) Å]. The coordination tetra­hedron is slightly flattened, the Ag atom is closer to the PPP plane; the P—Ag—P angles are wider than the Br—Ag—P angles. The voids in the crystal structure are filled with ordered acetonitrile solvent mol­ecules. The remaining electron density was inter­preted as a water mol­ecule, disordered over three alternative positions. Neither of the solvent mol­ecules is connected by any directional specific inter­actions with the complex. PMID:22219758

  13. Bromidotris(triphenyl-phosphane)silver acetonitrile monosolvate monohydrate.

    PubMed

    Owczarzak, Anita M; Kyros, Loukas; Hadjikakou, Sotiris K; Kubicki, Maciej

    2011-11-01

    In the title compound, [AgBr(C(18)H(15)P)(3)]·C(2)H(3)N·H(2)O, the coordination of the Ag atom is close to ideal tetra-hedral, with the three Ag-P bond lengths almost equal [2.5441 (10), 2.5523 (9) and 2.5647 (10) ° A] and the Ag-Br bond slightly longer [2.7242 (5) Å]. The coordination tetra-hedron is slightly flattened, the Ag atom is closer to the PPP plane; the P-Ag-P angles are wider than the Br-Ag-P angles. The voids in the crystal structure are filled with ordered acetonitrile solvent mol-ecules. The remaining electron density was inter-preted as a water mol-ecule, disordered over three alternative positions. Neither of the solvent mol-ecules is connected by any directional specific inter-actions with the complex. PMID:22219758

  14. Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures.

    PubMed

    Semino, Rocío; Zaldívar, Gervasio; Calvo, Ernesto J; Laria, Daniel

    2014-12-01

    We present molecular dynamics simulation results pertaining to the solvation of Li(+) in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li(+) is compared to the ones observed for infinitely diluted K(+) and Cl(-) species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl(-) shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li(+)Cl(-), contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements. PMID:25481154

  15. Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

    SciTech Connect

    Semino, Rocío; Zaldívar, Gervasio; Calvo, Ernesto J.; Laria, Daniel

    2014-12-07

    We present molecular dynamics simulation results pertaining to the solvation of Li{sup +} in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li{sup +} is compared to the ones observed for infinitely diluted K{sup +} and Cl{sup −} species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl{sup −} shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li{sup +}Cl{sup −}, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.

  16. Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

    NASA Astrophysics Data System (ADS)

    Semino, Rocío; Zaldívar, Gervasio; Calvo, Ernesto J.; Laria, Daniel

    2014-12-01

    We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely diluted K+ and Cl- species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl- shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li+Cl-, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.

  17. A convenient pathway to Sm(II)-mediated chemistry in acetonitrile.

    PubMed

    Maisano, Todd; Tempest, Kevin E; Sadasivam, Dhandapani V; Flowers, Robert A

    2011-03-21

    In this communication we show that the instability of samarium diiodide (SmI(2)) in acetonitrile is a consequence of ionization of the reductant in this solvent. Samarium triflate (Sm(OTf)(2)) is exceptionally stable in acetonitrile for periods over six months and can be used with appropriate additives to initiate a ketyl-olefin coupling reaction in high yield. PMID:21321772

  18. Dynamics of the NbCl5-catalyzed cycloaddition of propylene oxide and CO2 : assessing the dual role of the nucleophilic Co-catalysts.

    PubMed

    D'Elia, Valerio; Ghani, Amylia A; Monassier, Antoine; Sofack-Kreutzer, Julien; Pelletier, Jeremie D A; Drees, Markus; Vummaleti, Sai V C; Poater, Albert; Cavallo, Luigi; Cokoja, Mirza; Basset, Jean-Marie; Kühn, Fritz E

    2014-09-01

    A mechanistic study on the synthesis of propylene carbonate (PC) from CO2 and propylene oxide (PO) catalyzed by NbCl5 and organic nucleophiles such as 4-dimethylaminopyridine (DMAP) or tetra-n-butylammonium bromide (NBu4 Br) is reported. A combination of in situ spectroscopic techniques and kinetic studies has been used to provide detailed insight into the reaction mechanism, the formation of intermediates, and interactions between the reaction partners. The results of DFT calculations support the experimental observations and allow us to propose a mechanism for this reaction. PMID:25056457

  19. Processes and systems for the production of propylene glycol from glycerol

    DOEpatents

    Frye, John G; Oberg, Aaron A; Zacher, Alan H

    2015-01-20

    Processes and systems for converting glycerol to propylene glycol are disclosed. The glycerol feed is diluted with propylene glycol as the primary solvent, rather than water which is typically used. The diluted glycerol feed is sent to a reactor where the glycerol is converted to propylene glycol (as well as other byproducts) in the presence of a catalyst. The propylene glycol-containing product from the reactor is recycled as a solvent for the glycerol feed.

  20. Polymerization of Acetonitrile via a Hydrogen Transfer Reaction from CH3 to CN under Extreme Conditions

    DOE PAGESBeta

    Zheng, Haiyan; Li, Kuo; Cody, George D.; Tulk, Christopher A.; Dong, Xiao; Gao, Guoying; Molaison, Jamie J.; Liu, Zhenxian; Feygenson, Mikhail; Yang, Wenge; et al

    2016-08-25

    Acetonitrile (CH3CN) is the simplest and one of the most stable nitriles. Reactions usually occur on the C≡N triple bond, while the C-H bond is very inert and can only be activated by a very strong base or a metal catalyst. In this study, it is demonstrated that C-H bonds can be activated by the cyano group under high pressure, but at room temperature. The hydrogen atom transfers from the CH3 to CN along the CH···N hydrogen bond, which produces an amino group and initiates polymerization to form a dimer, 1D chain, and 2D nanoribbon with mixed sp2 and sp3more » bonded carbon. Lastly, it transforms into a graphitic polymer by eliminating ammonia. This study shows that applying pressure can induce a distinctive reaction which is guided by the structure of the molecular crystal. It highlights the fact that very inert C-H can be activated by high pressure, even at room temperature and without a catalyst.« less

  1. Polymerization of Acetonitrile via a Hydrogen Transfer Reaction from CH3 to CN under Extreme Conditions.

    PubMed

    Zheng, Haiyan; Li, Kuo; Cody, George D; Tulk, Christopher A; Dong, Xiao; Gao, Guoying; Molaison, Jamie J; Liu, Zhenxian; Feygenson, Mikhail; Yang, Wenge; Ivanov, Ilia N; Basile, Leonardo; Idrobo, Juan-Carlos; Guthrie, Malcolm; Mao, Ho-Kwang

    2016-09-19

    Acetonitrile (CH3 CN) is the simplest and one of the most stable nitriles. Reactions usually occur on the C≡N triple bond, while the C-H bond is very inert and can only be activated by a very strong base or a metal catalyst. It is demonstrated that C-H bonds can be activated by the cyano group under high pressure, but at room temperature. The hydrogen atom transfers from the CH3 to CN along the CH⋅⋅⋅N hydrogen bond, which produces an amino group and initiates polymerization to form a dimer, 1D chain, and 2D nanoribbon with mixed sp(2) and sp(3) bonded carbon. Finally, it transforms into a graphitic polymer by eliminating ammonia. This study shows that applying pressure can induce a distinctive reaction which is guided by the structure of the molecular crystal. It highlights the fact that very inert C-H can be activated by high pressure, even at room temperature and without a catalyst. PMID:27561179

  2. 21 CFR 172.856 - Propylene glycol mono- and diesters of fats and fatty acids.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Propylene glycol mono- and diesters of fats and... CONSUMPTION Multipurpose Additives § 172.856 Propylene glycol mono- and diesters of fats and fatty acids. Propylene glycol mono- and diesters of fats and fatty acids may be safely used in food, subject to...

  3. 21 CFR 500.50 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propylene glycol in or on cat food. 500.50 Section... Propylene glycol in or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat food is not generally recognized as safe and is a food additive subject to section 409...

  4. 21 CFR 500.50 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Propylene glycol in or on cat food. 500.50 Section... Propylene glycol in or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat food is not generally recognized as safe and is a food additive subject to section 409...

  5. 21 CFR 500.50 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Propylene glycol in or on cat food. 500.50 Section... Propylene glycol in or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat food is not generally recognized as safe and is a food additive subject to section 409...

  6. 21 CFR 500.50 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Propylene glycol in or on cat food. 500.50 Section... Propylene glycol in or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat food is not generally recognized as safe and is a food additive subject to section 409...

  7. 21 CFR 500.50 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Propylene glycol in or on cat food. 500.50 Section... Propylene glycol in or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat food is not generally recognized as safe and is a food additive subject to section 409...

  8. Laboratory investigations of irradiated acetonitrile-containing ices on an interstellar dust analog

    SciTech Connect

    Abdulgalil, Ali G. M.; Marchione, Demian; Rosu-Finsen, Alexander; Collings, Mark P.; McCoustra, Martin R. S.

    2012-07-15

    Reflection-absorption infrared spectroscopy is used to study the impact of low-energy electron irradiation of acetonitrile-containing ices, under conditions close to those in the dense star-forming regions in the interstellar medium. Both the incident electron energy and the surface coverage were varied. The experiments reveal that solid acetonitrile is desorbed from its ultrathin solid films with a cross section of the order of 10{sup -17} cm{sup 2}. Evidence is presented for a significantly larger desorption cross section for acetonitrile molecules at the water-ice interface, similar to that previously observed for the benzene-water system.

  9. Health and environmental-effects profile for propylene oxide

    SciTech Connect

    Not Available

    1985-06-01

    The Health and Environmental Effects Profile for propylene oxide was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life, and environmental effects of hazardous-waste constituents. Quantitative estimates are presented, provided sufficient data are available. Propylene oxide has been evaluated as a carcinogen. The human carcinogen potency factor (q1*) for propylene oxide is .239 (mg/kg/day)-2 for oral exposure. The Reportable Quantity (RQ) value of 1, 10, 100, 1000, or 5000 pounds is used to determine the quantity of a hazardous substance for which notification is required in the event of a release as specified by CERCLA based on chronic toxicity. The RQ value for propylene oxide is 1000.

  10. 21 CFR 177.1980 - Vinyl chloride-propylene copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Vinyl chloride-propylene copolymers. 177.1980 Section 177.1980 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1980...

  11. 21 CFR 172.858 - Propylene glycol alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Propylene glycol alginate. 172.858 Section 172.858 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives §...

  12. Enzymatic remediated biodegradation of propylene glycol 1,2-dinitrate

    SciTech Connect

    Meng, M.; Geelhaar, L.; Speedie, M.K.

    1995-12-31

    Two bacterial species, Enterobacter agglomerans and Bacillus thuringiensis/cereus, which were selected from nitroglycerin (GTN) contaminated soil, have previously been shown to have denitrating ability on nitroglycerin. This abstract presents the investigation of the cell free extracts from both microorganisms for the degradation of another nitrate ester contaminant; propylene glycol 1,2-dinitrate (PGDN). This compound has been previously considered resistant to the biodegradation. In order to probe the pathway, the whole process was monitored by using [1-{sup 14}C]-PGDN as substrate and the intermediates were identified by HPLC and TLC chromatography. Long term biodegradation experiments have shown that the enzymes in the cytoplasm fraction of Bacillus thuringiensis/cereus and the membrane fraction of Enterobacter agglomerans convert PGDN successively into propylene glycol 1-mononitrate (1-PGMN) and propylene glycol 2-mononitrate (2-PGMN), and finally, propylene glycol. The capacity to achieve sequential and complete degradation of PGDN implies that it follows a similar mechanism to that observed in the GTN degradation. Cofactor requirements for PGDN breakdown have been studied, it was found that no dissociable, dialyzable cofactors are required.

  13. EVALUATION OF MUTAGENIC AND CARCINOGENIC PROPERTIES OF BROMINATED AND CHLORINATED ACETONITRILES: BY-PRODUCTS OF CHLORINATION

    EPA Science Inventory

    The present study was undertaken to determine if chlorinated and brominated acetonitriles formed during the chlorination of drinking water possess mutagenic and/or carcinogenic properties. Chloroacetonitrile (CAN), dichloroacetonitrile (DCAN), trichloroacetonitrile (TCAN), bromoc...

  14. Facilitated Diffusion of Acetonitrile Revealed by Quantitative Breath Analysis Using Extractive Electrospray Ionization Mass Spectrometry

    PubMed Central

    Li, Ming; Ding, Jianhua; Gu, Haiwei; Zhang, Yan; Pan, Susu; Xu, Ning; Chen, Huanwen; Li, Hongmei

    2013-01-01

    By using silver cations (Ag+) as the ionic reagent in reactive extractive electrospray ionization mass spectrometry (EESI-MS), the concentrations of acetonitrile in exhaled breath samples from the volunteers including active smokers, passive smokers, and non-smokers were quantitatively measured in vivo, without any sample pretreatment. A limit of detection (LOD) and relative standard deviation (RSD) were 0.16 ng/L and 3.5% (n = 8), respectively, for the acetonitrile signals in MS/MS experiments. Interestingly, the concentrations of acetonitrile in human breath continuously increased for 1–4 hours after the smoker finished smoking and then slowly decreased to the background level in 7 days. The experimental data of a large number of (> 165) samples indicated that the inhaled acetonitrile is excreted most likely by facilitated diffusion, instead of simple diffusion reported previously for other volatile compounds. PMID:23386969

  15. Propylene Glycol Poisoning From Excess Whiskey Ingestion: A Case of High Osmolal Gap Metabolic Acidosis.

    PubMed

    Cunningham, Courtney A; Ku, Kevin; Sue, Gloria R

    2015-01-01

    In this report, we describe a case of high anion gap metabolic acidosis with a significant osmolal gap attributed to the ingestion of liquor containing propylene glycol. Recently, several reports have characterized severe lactic acidosis occurring in the setting of iatrogenic unintentional overdosing of medications that use propylene glycol as a diluent, including lorazepam and diazepam. To date, no studies have explored potential effects of excess propylene glycol in the setting of alcohol intoxication. Our patient endorsed drinking large volumes of cinnamon flavored whiskey, which was likely Fireball Cinnamon Whisky. To our knowledge, this is the first case of propylene glycol toxicity from an intentional ingestion of liquor containing propylene glycol. PMID:26904700

  16. IR spectra and structure of (4-nitrophenyl)acetonitrile and of its carbanion: experimental and ab initio studies

    NASA Astrophysics Data System (ADS)

    Binev, Y. I.; Petrova, R. R.; Tsenov, J. A.; Binev, I. G.

    2000-01-01

    The structures of (4-nitrophenyl)acetonitrile and of its carbanion were studied on the basis of both quantitative IR spectra and ab initio force field calculations. The spectral and structural changes, which take place in the course of the conversion of the parent molecule into the carbanion, are essential and spread over the whole species. In agreement between theory and experiment, the conversion studied causes strong frequency decreases (down to 136 cm -1) and intensity increases (up to 90-fold) of the cyano and nitro stretching bands. The molecule→carbanion conversion is accompanied by both quinoidization of the phenylene ring and a change in the configuration of the methylenic carbon atom: from tetrahedral in the molecule it becomes planar in the carbanion. The carbanionic charge is delocalized over the carbanionic center (0.40 e -), phenylene (0.24 e -), nitro (0.21 e -) and cyano (0.15 e -) groups.

  17. Interaction of acetonitrile with the surfaces of amorphous and crystalline ice

    SciTech Connect

    Schaff, J.E.; Roberts, J.T.

    1999-10-12

    The adsorption of acetonitrile (CH{sub 3}CN) on ultrathin films of ice under ultrahigh vacuum was investigated with temperature-programmed desorption ass spectrometry (TPD) and Fourier transform infrared reflection absorption spectroscopy (FTIRAS). Two types of film were studied, amorphous and crystalline. On the amorphous films, two sates of adsorbed acetonitrile were observed by TPD and FTIRAS. One of the states is attributed to acetonitrile that is hydrogen bonded to agree OH group at the ice surface; the other state is assigned to acetonitrile that is purely physiorbed. Evidence for the hydrogen-bonded state is two-fold. First, there is a large kinetic isotope effect for desorption from H{sub 2}O-and D{sub 2}O-ice: the desorption temperatures from ice-h{sub 2} and ice-d{sub 2} are {approximately}161 and {approximately}176 K, respectively. Second, the C{triple{underscore}bond}N stretching frequency (2,265 cm{sup {minus}1}) is 16 cm{sup {minus}1} is greater than that of physisorbed acetonitrile, and it is roughly equal to that of acetonitrile which is hydrogen bonded to an OH group at the air-liquid water interface. On the crystalline films, there is no evidence for a hydrogen-bonded state in the TPD spectra. The FTIRAS spectra do show that some hydrogen-bonded acetonitrile is present but at a maximum coverage that is roughly one-sixth of that on the amorphous surface. The difference between the amorphous and crystalline surfaces cannot be attributed to a difference n surface areas. Rather, this work provides additional evidence that the surface chemical properties of amorphous ice are different from those of crystalline ice.

  18. Propylene based systems for high voltage cable insulation applications

    NASA Astrophysics Data System (ADS)

    Hosier, I. L.; Cozzarini, L.; Vaughan, A. S.; Swingler, S. G.

    2009-08-01

    Crosslinked polyethylene (XLPE) remains the material of choice for extruded high voltage cables, possessing excellent thermo-mechanical and electrical properties. However, it is not easily recyclable posing questions as to its long term sustainability. Whilst both polyethylene and polypropylene are widely recycled and provide excellent dielectric properties, polypropylene has significantly better mechanical integrity at high temperatures than polyethylene. However, while isotactic polypropylene is too stiff at room temperature for incorporation into a cable system, previous studies by the authors have indicated that this limitation can be overcome by using a propylene-ethylene copolymer. Whilst these previous studies considered unrelated systems, the current study aims to quantify the usefulness of a series of related random propylene-ethylene co-polymers and assesses their potential for replacing XLPE.

  19. Epoxidation of propylene dimers and isomerization of mixtures obtained

    SciTech Connect

    Dobrev, D.M.; Kurtev, K.S.

    1988-05-10

    Mixtures of hexenes are obtained in the dimerization of propylene on a Ziegler catalyst. By the epoxidation of this mixture by organic peroxides, followed by isomerization of the oxides, C/sub 6/ ketones, which are used as solvents, can be obtained. The hexenes were obtained by dimerization of propylene in the presence of a Ni(C/sub 5/H/sub 7/O/sub 2/)/sub 2/-P(C/sub 6/H/sub 5/)/sub 3/-(C/sub 3/H/sub 5/)/sub 2/AlCl catalytic system. The epoxidation was carried with technical grade isopropylbenzyl hydroperoxide (IPBHP). MoO/sub 2/(C/sub 5/H/sub 7/O/sub 2/)/sub 2/ was used as the catalyst. The relative rates of epoxidation of different isomers contained in the dimeric fraction, with respect to 2-methyl-1-pentene, was determined by means of competing reactions.

  20. Hole schubweg in FEP (fluorinated ethylene propylene copolymer)

    NASA Astrophysics Data System (ADS)

    Wintle, H. J.

    We discuss four models to account for observations of a constant hole schubweg in FEP (fluorinated ethylene propylene copolymer). Inhomogeneity in the sample and one-dimensional chain transport seem unlikely, while conventional semiconductor theory demands a particular combination of properties. Tunnelling, influenced by the field to yield essentially unidirectional transport, matches the observations and gives a reasonable trap density ( N ≈ 10 19 cm -3, with wide limits of uncertainty).

  1. Aqueous Two-Phase Systems formed by Biocompatible and Biodegradable Polysaccharides and Acetonitrile

    PubMed Central

    de Brito Cardoso, Gustavo; Souza, Isabela Nascimento; Pereira, Matheus M.; Freire, Mara G.; Soares, Cleide Mara Faria; Lima, Álvaro Silva

    2015-01-01

    In this work, it is shown that novel aqueous two-phase systems can be formed by the combination of acetonitrile and polysaccharides, namely dextran. Several ternary phase diagrams were determined at 25 °C for the systems composed of water + acetonitrile + dextran. The effect of the dextran molecular weight (6,000, 40,000 and 100,000 g.mol−1) was ascertained toward their ability to undergo liquid-liquid demixing. An increase in the dextran molecular weight favors the phase separation. Furthermore, the effect of temperature (25, 35 and 45 °C) was evaluated for the system constituted by the dextran of higher molecular weight. Lower temperatures are favorable for phase separation since lower amounts of dextran and acetonitrile are required for the creation of aqueous two-phase systems. In general, acetonitrile is enriched in the top phase while dextran is majorly concentrated in the bottom phase. The applicability of this new type of two-phase systems as liquid-liquid extraction approaches was also evaluated by the study of the partition behavior of a well-known antioxidant – vanillin - and used here as a model biomolecule. The optimized conditions led to an extraction efficiency of vanillin of 95% at the acetonitrile-rich phase. PMID:25729320

  2. Acetone as a greener alternative to acetonitrile in liquid chromatographic fingerprinting.

    PubMed

    Funari, Cristiano Soleo; Carneiro, Renato Lajarim; Khandagale, Manish M; Cavalheiro, Alberto José; Hilder, Emily F

    2015-05-01

    A considerable amount of chemical waste from liquid chromatography analysis is generated worldwide. Acetonitrile is the most employed solvent in liquid chromatography analyses since it exhibits favorable physicochemical properties for separation and detection, but it is an unwelcome solvent from an environmental point of view. Acetone might be a much greener alternative to replace acetonitrile in reversed-phase liquid chromatography, since both share similar physicochemical properties, but its applicability with ultraviolet absorbance-based detectors is limited. In this work, a reference method using acetonitrile and high-performance liquid chromatography coupled to an ultraviolet photodiode array detector coupled to a corona charged aerosol detector system was developed to fingerprint a complex sample. The possibility of effectively substituting acetonitrile with acetone was investigated. Design of experiments was adopted to maximize the number of peaks acquired in both fingerprint developments. The methods with acetonitrile or acetone were successfully optimized and proved to be statistically similar when only the number of peaks or peak capacity was taken into consideration. However, the superiority of the latter was evidenced when parameters of separation and those related to greenness were heuristically combined. A green, comprehensive, time- and resource-saving approach is presented here, which is generic and applicable to other complex matrices. Furthermore, it is in line with environmental legislation and analytical trends. PMID:25708832

  3. [Effect of Acetonitrile and n-hexane on the Immunoassay of Environmental Representative Pollutants].

    PubMed

    Lou, Xue-ning; Zhou, Li-ping; Song, Dan; Yang, Rong; Long, Feng

    2016-01-15

    Based on indirect competitive immunoassay mechanism, bisphenol A (BPA) was detected by the evanescent wave all-fiber immunosensor previously developed with the detection limit of 0.2 microg x L(-1) and the linear detection range of 0.3-33.4 microg x L(-1). The effects of two commonly used organic solvents, including acetonitrile and n-hexane, on the immunosensing assay of BPA were investigated. The influence mechanism of organic solvents on immunosensing assay was discussed. The experimental results showed that the effect of n-hexane on immunosensing assay was negligible even at a high concentration of up to 10%, whereas the effect of acetonitrile on the immunosensing assay was relatively great. BPA could be detected in solutions containing a low concentration of acetonitrile. However, the specific binding reaction between antibody and antigen in homogeneous solution was completely inhibited by high concentrations of acetonitrile, and the quantitative analysis of BPA was not achieved. This might result from the changes of antibody conformation or binding capability between antibody and antigen because acetonitrile replaced a part of the water molecules on the antibody surface. PMID:27078982

  4. Characterization of acetonitrile-tolerant marine bacterium Exiguobacterium sp. SBH81 and its tolerance mechanism.

    PubMed

    Kongpol, Ajiraporn; Kato, Junichi; Tajima, Takahisa; Vangnai, Alisa S

    2012-01-01

    A Gram-positive marine bacterium, Exiguobacterium sp. SBH81, was isolated as a hydrophilic organic-solvent tolerant bacterium, and exhibited high tolerance to various types of toxic hydrophilic organic solvents, including acetonitrile, at relatively high concentrations (up to 6% [v/v]) under the growing conditions. Investigation of its tolerance mechanisms illustrated that it does not rely on solvent inactivation processes or modification of cell surface characteristics, but rather, increase of the cell size lowers solvent partitioning into cells and the extrusion of solvents through the efflux system. A test using efflux pump inhibitors suggested that secondary transporters, i.e. resistance nodulation cell division (RND) and the multidrug and toxic compound extrusion (MATE) family, are involved in acetonitrile tolerance in this strain. In addition, its acetonitrile tolerance ability could be stably and significantly enhanced by repetitive growth in the presence of toxic acetonitrile. The marked acetonitrile tolerance of Exiguobacterium sp. SBH81 indicates its potential use as a host for biotechnological fermentation processes as well as bioremediation. PMID:21971080

  5. Determination of M/G ratio of propylene glycol alginate sodium sulfate by HPLC with pre-column derivatization.

    PubMed

    Wu, Jian; Zhao, Xia; Ren, Li; Xue, Yiting; Li, Chunxia; Yu, Guangli; Guan, Huashi

    2014-04-15

    A reliable high performance liquid chromatography with pre-column derivatization method was developed for the determination of the mannuronic acid (M)/guluronic acid (G) ratio of propylene glycol alginate sodium sulfate (PSS). The hydrolysis conditions of PSS were investigated by four degradation methods based on the degree of destruction of M and G, and the chromatographic separation conditions were also optimized. A satisfactory resolution of M and G was achieved with a KP-C18 column using 0.1 mol/L phosphate buffer (pH 7.0)-acetonitrile (83/17, v/v) as a mobile phase, after PSS was hydrolyzed with 0.1 mol/L sulfuric acid and labeled with 1-phenyl-3-methyl -5-pyrazolone. The M/G ratio of PSS determined by this method was in good accordance with that obtained by the (1)H NMR method with a desulfurization strategy. Our method is rapid, sensitive, accurate and reproducible. The limit of detection was found to be 0.25 μg/mL for M and 0.40 μg/mL for G. PMID:24607155

  6. Powder X-ray studies of meso-hexamethyl propylene amine oxime (meso-HMPAO) in two different phases.

    PubMed

    Al-Ktaifani, Mahmoud; Rukiah, Mwaffak

    2010-09-01

    Two different forms of meso-3,3'-[2,2-dimethylpropane-1,3-diylbis(azanediyl)]dibutan-2-one dioxime, commonly called meso-hexamethyl propylene amine oxime (HMPAO), C(13)H(28)N(4)O(2), designated alpha and beta, were isolated by fractional crystallization and their crystal structures were determined by powder X-ray diffraction using the direct-space method with the parallel tempering algorithm. The alpha form was first crystallized from acetonitrile solution, while the beta form was obtained by recrystallization of the alpha phase from diethyl ether. The alpha form crystallizes in the triclinic system (space group P-1), with one molecule in the asymmetric unit, while the crystal of the beta form is monoclinic (space group P2(1)/n), with one molecule in the asymmetric unit. In both phases, the molecules have similar conformations and RS/EE geometric isomerism. The crystal packing of the two phases is dominated by intermolecular hydrogen-bonding interactions between the two O-H oxime groups of an individual molecule and the amine N atoms of two different adjacent molecules, which lead to segregation of extended poly(meso-HMPAO) one-dimensional chains along the c direction. The structures of the two phases are primarily different due to the different orientations of the molecules in the chains. PMID:20814112

  7. Electrochemical polymerization of aniline on carbon-aluminum electrodes for energy storage

    NASA Astrophysics Data System (ADS)

    Chandrasoma, Asela; Grant, Robert; Bruce, Alice E.; Bruce, Mitchell R. M.

    2012-12-01

    We report a simple and reliable method to electrochemically synthesize PANi on aluminum carbon (Al/C).Aluminum electrodes were coated with hard black graphite. Polyaniline was then deposited in steps from +0.75 V to +0.825 V (V vs. Ag/AgCl) in low pH growth solutions containing aniline and camphor sulphonic acid. The polyaniline films were rinsed in hydrazine solution and dried in an infrared oven under a nitrogen atmosphere. The films were transferred and are stable in a 50:50 (v/v) propylene carbonate (PC)/acetonitrile (ACN) solvent mixture containing 0.5 M LiClO4 electrolyte. Cyclic voltammetry and charge-discharge capacities are reported. Microscope (SEM) images of Al/C/PANi and Pt/PANi films show similar structural details and morphology. The specific capacity for Al/C/PANi in nonaqueous solutions was ca. 133 mAh g-1, in good agreement with the reported data for other PANi-based electrodes. The performance studies and SEM images demonstrate similar results for Pt/PANi and Al/C/PANi electrodes.

  8. Novel adsorption distillation hybrid scheme for propane/propylene separation

    SciTech Connect

    Kumar, R.; Golden, T.C.; White, T.R.; Rokicki, A. )

    1992-12-01

    A novel adsorption-distillation hybrid scheme is proposed for propane/propylene separation. The suggested scheme has potential for saving up to [approximately]50% energy and [approximately]15-30% in capital costs as compared with current technology. The key concept of the proposed scheme is to separate olefins from alkanes by adsorption and then separate individual olefins and alkanes by simple distillation, thereby eliminating energy intensive and expensive olefin-alkane distillation. A conceptual flow schematic for the proposed hybrid scheme and potential savings are outlined.s

  9. Propylene oxide causes central-peripheral distal axonopathy in rats

    SciTech Connect

    Ohnishi, A.; Yamamoto, T.; Murai, Y.; Hayashida, Y.; Hori, H.; Tanaka, I.

    1988-09-01

    In Wistar rats subjected daily to a 6-hr exposure of propylene oxide (PO) at a concentration of 1,500 ppm (5 times a wk for 7 wk), ataxia developed in the hindlegs. Myelinated fibers in hindleg nerves and in the fasciculus gracilis showed axonal degeneration, sparing the nerve cell body of the first sacral dorsal root ganglion and myelinated fibers of the first sacral dorsal and ventral roots. These pathologic findings are compatible with central-peripheral distal axonopathy. This is apparently the first animal model of PO neuropathy to be verified histologically.

  10. DEVELOPMENTAL TOXICITY OF HALOGENATED ACETONITRILES: DRINKING WATER BY-PRODUCTS OF CHLORINE DISINFECTION

    EPA Science Inventory

    The developmental toxicity of acetonitrile and five halogenated derivatives was examined with an in vivo teratology screen adapted for use in the Long Evans rat. The screen was extended to an evaluation of growth till postnatal days 41-42, and weight of several organs at sacrific...

  11. Stacking and separation of coproporphyrin isomers by acetonitrile-salt mixtures in micellar electrokinetic chromatography.

    PubMed

    So, T S; Jia, L; Huie, C W

    2001-07-01

    The effectiveness of the addition of salt and acetonitrile in the sample matrix to induce narrowing of the analyte zones is demonstrated for the first time in micellar electrokinetic chromatography (MEKC). Using coproporphyrin (CP) I and III isomers as test compounds, the use of sodium cholate (SC) as the micelle in the separation buffer and a high concentration of sodium chloride in the aqueous sample solution (without the presence of an organic solvent) were found to provide enhancement in peak heights for both CP I and III, but yielded very poor resolution of these two positional isomers at sample size of 10% capillary volume or larger. With the addition of acetonitrile as the organic solvent in the aqueous sample solution (acetonitrile-salt mixtures), baseline/partial resolution of CP I and III was obtained even at large injection volumes, along with significant increase in peak heights for both isomers. Possible mechanisms responsible for the narrowing of analyte zones are briefly discussed. The effects of experimental parameters, such as concentrations of salt and acetonitrile, on peak heights and resolution of the test compounds were studied. Importantly, the usefulness of the present method was demonstrated for the MEKC determination of endogenous CP I and III present in normal urine samples with good separation and detection performances. PMID:11504047

  12. The adsorption and reaction of Acetonitrile on clean and oxygen covered Ag(110) surfaces

    NASA Astrophysics Data System (ADS)

    Capote, Armand J.; Hamza, Alex V.; Canning, Nicholas D. S.; Madix, Robert J.

    1986-10-01

    The adsorption and reaction of acetonitrile (CH 3CN) on clean and oxygen covered Ag(110) surfaces has been studied using temperature programmed reaction spectroscopy (TPRS), isotope exchange, chemical displacement reactions and high resolution electron energy loss spectroscopy (EELS). On the clean Ag(110) surface, CH 3CN was reversibly adsorbed, desorbing with an activation energy of 10 kcal mol -1 at 166 K from a monolayer state and at 158 K from a multilayer state. Vibrational spectra of multilayer, monolayer and sub-monolayer CH 3CN were in excellent agreement with that of gas phase CH 3CN indicating that CH 3CN is only weakly bonded to the clean Ag(110) surface. On the partially oxidized surface CH 3CN reacts with atomic oxygen to form adsorbed CH 2CN, OH and H 2O in addition to forming another molecular adsorption state with a desorption peak at 240 K. This molecular state shows a CN stretching frequency of 1840 cm -1, which is indicative of substantial rehybridization of the CN bond and is associated with side-on coordination via the π system. The CH 2CN species is stable up to 430 K, where C-H bond breaking and reformation begins, leading to the formation of CH 3CN at 480 K and HCN at 510 K and leaving only carbon on the surface. In the presence of excess oxygen atoms C-H bond breaking and reformation is more facile leading to additional desorption peaks for CH 3CN and H 2O at 420 K. This destabilizing effect of O (a) on Ch 2CN (a) is explained in terms of an anionic (CH 2CN -1) species. Comparison of the vibrational spectra from CH 2CN (a) and CD 2CN (a) supports the following assignment for the modes of adsorbed CH 2CN: ν(Ag-C) 215: δ(CCN) 545; ϱ t(CH 2) 695; ϱ w(CH 2) 850; ν(C-C) 960; ϱ r(CH 2) 1060; δ(CH 2) 1375; ν(CN) 2075; and ν(CH 2) 2940 cm -1. These results serve to further indicate the wide applicability of the acid-base reaction concept for reactions between gas phase Brönsted acids and adsorbed oxygen atoms on solver surfaces.

  13. Why a diaminopyrrolic tripodal receptor binds mannosides in acetonitrile but not in water?

    PubMed Central

    Vila-Viçosa, Diogo; Francesconi, Oscar

    2014-01-01

    Summary Intermolecular interactions involving carbohydrates and their natural receptors play important roles in several biological processes. The development of synthetic receptors is very useful to study these recognition processes. Recently, it was synthetized a diaminopyrrolic tripodal receptor that is selective for mannosides, which are obtained from mannose, a sugar with significant relevance in living systems. However, this receptor is significantly more active in acetonitrile than in water. In this work, we performed several molecular dynamics and constant-pH molecular dynamics simulations in acetonitrile and water to evaluate the conformational space of the receptor and to understand the molecular detail of the receptor–mannoside interaction. The protonation states sampled by the receptor show that the positive charges are always as distant as possible in order to avoid large intramolecular repulsions. Moreover, the conformational space of the receptor is very similar in water above pH 4.0 and in acetonitrile. From the simulations with the mannoside, we observe that the interactions are more specific in acetonitrile (mainly hydrogen bonds) than in water (mainly hydrophobic). Our results suggest that the readiness of the receptor to bind mannoside is not significantly affected in water (above pH 4.0). Probably, the hydrogen bond network that is formed in acetonitrile (which is weaker in water) is the main reason for the higher activity in this solvent. This work also presents a new implementation of the stochastic titration constant-pH molecular dynamics method to a synthetic receptor of sugars and attests its ability to describe the protonation/conformation coupling in these molecules. PMID:25161708

  14. 21 CFR 172.856 - Propylene glycol mono- and diesters of fats and fatty acids.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Propylene glycol mono- and diesters of fats and... diesters of fats and fatty acids. Propylene glycol mono- and diesters of fats and fatty acids may be safely used in food, subject to the following prescribed conditions: (a) They are produced from edible...

  15. 21 CFR 172.856 - Propylene glycol mono- and diesters of fats and fatty acids.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Propylene glycol mono- and diesters of fats and... diesters of fats and fatty acids. Propylene glycol mono- and diesters of fats and fatty acids may be safely used in food, subject to the following prescribed conditions: (a) They are produced from edible...

  16. 21 CFR 172.856 - Propylene glycol mono- and diesters of fats and fatty acids.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Propylene glycol mono- and diesters of fats and... diesters of fats and fatty acids. Propylene glycol mono- and diesters of fats and fatty acids may be safely used in food, subject to the following prescribed conditions: (a) They are produced from edible...

  17. 21 CFR 172.856 - Propylene glycol mono- and diesters of fats and fatty acids.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Propylene glycol mono- and diesters of fats and... diesters of fats and fatty acids. Propylene glycol mono- and diesters of fats and fatty acids may be safely used in food, subject to the following prescribed conditions: (a) They are produced from edible...

  18. 21 CFR 589.1001 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propylene glycol in or on cat food. 589.1001... or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat... on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug,...

  19. 21 CFR 589.1001 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Propylene glycol in or on cat food. 589.1001... or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat... on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug,...

  20. 21 CFR 589.1001 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Propylene glycol in or on cat food. 589.1001... or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat... on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug,...

  1. 21 CFR 589.1001 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Propylene glycol in or on cat food. 589.1001... or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat... on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug,...

  2. 21 CFR 589.1001 - Propylene glycol in or on cat food.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Propylene glycol in or on cat food. 589.1001... or on cat food. The Food and Drug Administration has determined that propylene glycol in or on cat... on cat food causes the feed to be adulterated and in violation of the Federal Food, Drug,...

  3. Palladium-catalyzed oxidative arylalkylation of activated alkenes: dual C-H bond cleavage of an arene and acetonitrile.

    PubMed

    Wu, Tao; Mu, Xin; Liu, Guosheng

    2011-12-23

    Not one but two: The title reaction proceeds through the dual C-H bond cleavage of both aniline and acetonitrile. The reaction affords a variety of cyano-bearing indolinones in excellent yield. Mechanistic studies demonstrate that this reaction involves a fast arylation of the olefin and a rate-determining C-H activation of the acetonitrile. PMID:22076660

  4. Transparent Films from CO2 -Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing.

    PubMed

    Subhani, Muhammad Afzal; Köhler, Burkhard; Gürtler, Christoph; Leitner, Walter; Müller, Thomas E

    2016-04-25

    Transparent films were prepared by cross-linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO2 , propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron-acceptor and electron-donor groups enables particularly facile UV- or redox-initiated free-radical curing. The resulting materials are transparent and highly interesting for coating applications. PMID:27028458

  5. Electrosynthesis and characterization of oligophenylene deriving from 4-(methoxyphenyl)acetonitrile

    NASA Astrophysics Data System (ADS)

    Amor, Sarra Ben; Said, Ayoub Haj; Chemek, Mourad; Ayachi, Sahbi; Massuyeau, Florian; Wéry, Jany; Alimi, Kamel; Roudesli, Sadok

    2013-01-01

    An oligophenylene deriving from the 4-(methoxyphenyl)acetonitrile (MPA), was electrosynthesized by direct anodic oxidation at a constant potential in acetonitrile on a platinium electrode. This oligomer (OMPA) showed a good solubility in common organic solvents. The results of osmometry and gel permeation chromatography analyzes indicated that the average chain length for OMPA was about 5 units. Its chemical structure was elucidated by 1H and 13C NMR, FTIR and UV spectroscopy. A thermal study carried out by thermogravimetric analysis and Differential Scanning Calorimetry showed that the oligomer was stable up to 268 °C. In addition, the photoluminescent properties of OMPA were investigated. In solution, an emission was recorded in the indigo-blue region, however, in solid state this emission was shifted to the orange-red zone. Finally a mechanism for the electro-oligomerization was evoked in the light of the electronic structures of the MPA and its radical cation obtained by DFT calculation.

  6. Copper(I) halide adducts with acetonitrile: an infrared and Raman investigation

    NASA Astrophysics Data System (ADS)

    Zarembowitch, J.; Maleki, R.

    Infrared (4000-200 cm -1) and Raman (4000-15 cm -1) spectra are reported for polycrystalline samples of aN . CuCl and aN . CuBr (aN = acetonitrile). Comparison with the spectral data obtained for liquid acetonitrile leads to a thorough assignment of the bands. The frequency shifts of the stretching modes νCN, νCCN and νCH upon coordination is discussed. The loosening observed for the CH bonds and the fact that the νCN frequency increases only slightly (20 cm -1) upon coordination are accounted for by the existence of a significant π back-bonding from copper(I) to nitrogen. The stretching fundamentals νCuN and νCuX can be identified unambiguously.

  7. Copper-mediated direct C2-cyanation of indoles using acetonitrile as the cyanide source.

    PubMed

    Pan, Changduo; Jin, Hongming; Xu, Pan; Liu, Xu; Cheng, Yixiang; Zhu, Chengjian

    2013-09-20

    A copper-mediated C2-cyanation of indoles using cheap and commercially available acetonitrile as the "nonmetallic" cyanide source was achieved through sequential C-C and C-H bond cleavages. The installation of a removable pyrimidyl group on the indole nitrogen atom is the key for this C2 selectivity. This approach provides a novel and alternative route leading to indole-2-carbonitrile. PMID:23957858

  8. Photochemistry of rose bengal in water and acetonitrile: a comprehensive kinetic analysis.

    PubMed

    Ludvíková, Lucie; Friš, Pavel; Heger, Dominik; Šebej, Peter; Wirz, Jakob; Klán, Petr

    2016-06-28

    The photophysical and photochemical properties of rose bengal (RB) in degassed aqueous and acetonitrile solutions were studied using steady-state and transient absorption spectroscopies. This comprehensive investigation provides detailed information about the kinetics and the optical properties of all intermediates involved: the triplet excited state and the oxidized and reduced forms of RB. A full kinetic description is used to control the concentrations of these intermediates by changing the initial experimental conditions. PMID:27253480

  9. Complex formation of Am(III) and Am(IV) with phosphate ions in acetonitrile solutions

    SciTech Connect

    Perevalov, S.A.; Lebedev, I.A.; Myasoedov, B.F.

    1988-05-01

    The first dissociation constant of H/sub 3/PO/sub 4/ in acetonitrile solution (K/sub 1//sup 0/ = 1.75/centered dot/10/sup /minus/13/) and the constant of formation of H(H/sub 2/PO/sub 4/)/sub 2//sup /minus// dimers (K/sub d//sup 0/ = 8/centered dot/10/sup 2/) were determined by the method of pH-potentiometry. The complex formation of Am(III) in acetonitrile solutions containing 0.05-2.0 M H/sub 3/PO/sub 4/ was investigated by a spectrophotometric method; the stability constants of the complexes AmH/sub 2/PO/sub 4//sup 2+/ (/beta//sub 1//sup III/ = 1.0/centered dot/10/sup 12/) and Am(H/sub 2/PO/sub 4/)/sub 2//sup +/ (/beta//sub 2//sup III/ = 4.3/centered dot/10/sup 24/) were determined. The formal potentials of the couple Am/sup (IV)//Am/sup (III)/ in 0.3-1.9 M solutions of H/sub 3/PO/sub 4/ in acetonitrile were measured, and the stability constant of the phosphate complex of tetravalent americium Am(H/sub 2/PO/sub 4/)/sub 3//sup +/ (/beta//sub 3//sup IV/ = 2.5/centered dot/10/sup 46/) was calculated according to the value of the shift of the potential relative to the standard.

  10. Ethylene-Propylene Terpolymer Rubber Processing by Electron Beam Irradiation

    NASA Astrophysics Data System (ADS)

    Manaila, Elena N.; Zuga, Maria Daniela T.; Martin, Diana I.; Craciun, Gabriela D.; Ighigeanu, Daniel I.; Matei, Constantin I.

    2007-04-01

    The investigations on the cross-linking by accelerated electrons of 6.23 MeV in lowly unsaturated elastomers of EPDM (ethylene-propylene terpolymer rubber) type are presented. Two rubber blends based EPDM were prepared and irradiated at different doses up to 250kGy: blend A - based on EPDM maleinized with polyethylene, zinc oxide, plasticizers, filler, and blend B - based on EPDM / PE (50 % EPDM and 50% polyethylene). Blends were prepared on a laboratory electrically heated rubber mill at temperatures of 150-160°C to enable the polyethylene (PE) melting to be reached. Plates of 150 × 150 × 2 mm were obtained in a laboratory electrical press at 170°C.

  11. Homogeneous models for mechanisms of surface reactions: Propylene ammoxidation

    SciTech Connect

    Chan, D.M.T.; Nugent, W.A.; Fultz, W.C.; Rose, D.C.; Tulip, T.H.

    1987-04-01

    The proposed active sites on the catalyst surface in heterogeneous propylene ammoxidation have been successfully modelled by structurally characterized pinacolato W(VI) tert-butylimido complexes. These compounds exist as an equilibrating mixture of amine-bis(imido) and imido-bis(amido) complexes, the position of this equilibrium is dependent on the electronic nature of the glycolate ligand. Both of the C-N bond-forming reactions proposed in recent studies by Grasselli et al. (1) have been reproduced using discrete Group VI d{sup 0} organoimido complexes under mild conditions suitable for detailed mechanistic studies. These reactions are: (1) oxidative trapping of radicals at molybdenum imido sites, and (2) migration of the allyl group from oxygen to an imido nitrogen atom.

  12. Temperature effects on propylene glycol-contaminated soil cores

    SciTech Connect

    Davis-Hoover, W.J.; Vesper, S.J.

    1995-12-31

    The authors are examining the effect of temperature on the biodegradation of propylene glycol (PPG) in subsurface soil cores. Subsurface soils were contaminated in situ with PPG and allowed to diffuse into the soil for 30 days. The treated soil was reexposed, and intact were incubated for 30 days at temperatures ranging from 9 to 39 C in a temperature gradient incubator. At 30 days, soil moisture, soil pH, microbial activity [fluorescein diacetate (FDA) test], R2A plate counts, and plate counts of PPG degraders were studied. Although the soil moisture and pH remained relatively unchanged, the parameters of microbial activity varied rather consistently with temperature. Multiple populations or subpopulations of bacteria appear to exist between temperatures of 9 and 39 C in these soils.

  13. Viscoelastic Properties of Fluorinated Ethylene-Propylene (FEP) Random Copolymers

    NASA Astrophysics Data System (ADS)

    Curtin, Megan; Wright, Benjamin; Ozisik, Rahmi

    Florinated ethylene-propylene (FEP) random copolymers contain tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) repeat units. FEP is an excellent alternative to poly(tetrafluoroethylene), PTFE, which cannot be melt processed due to its high molecular weight and extensive crystallinity. On the other hand, FEP is a melt processible polymer and offers similar if not the same properties as PTFE. Many studies have been performed on FEP over the years, however, the properties of these polymers strongly depend on the HFP concentration and molecular weight (distribution). Just like PTFE, FEP cannot be dissolved in many solvents, therefore, obtaining molecular weight distribution of these polymers is not possible with commonly used methods. In the current study, we perform rheological analysis of various FEPs and obtain their molecular weight distributions by employing the Tuminello method. This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1538730.

  14. Developmental pharmacokinetics of propylene glycol in preterm and term neonates

    PubMed Central

    De Cock, Roosmarijn F W; Knibbe, Catherijne A J; Kulo, Aida; de Hoon, Jan; Verbesselt, Rene; Danhof, Meindert; Allegaert, Karel

    2013-01-01

    AIM Propylene glycol (PG) is often applied as an excipient in drug formulations. As these formulations may also be used in neonates, the aim of this study was to characterize the pharmacokinetics of propylene glycol, co-administered intravenously with paracetamol (800 mg PG/1000 mg paracetamol) or phenobarbital (700 mg PG/200 mg phenobarbital) in preterm and term neonates. METHODS A population pharmacokinetic analysis was performed based on 372 PG plasma concentrations from 62 (pre)term neonates (birth weight (bBW) 630–3980 g, postnatal age (PNA) 1–30 days) using NONMEM 6.2. The model was subsequently used to simulate PG exposure upon administration of paracetamol or phenobarbital in neonates (gestational age 24–40 weeks). RESULTS In a one compartment model, birth weight and PNA were both identified as covariates for PG clearance using an allometric function (CLi= 0.0849 × {(bBW/2720)1.69× (PNA/3)0.201}). Volume of distribution scaled allometrically with current bodyweight (Vi= 0.967 × {(BW/2720)1.45}) and was estimated 1.77 times higher when co-administered with phenobarbital compared with paracetamol. By introducing these covariates a large part of the interindividual variability on clearance (65%) as well as on volume of distribution (53%) was explained. The final model shows that for commonly used dosing regimens, the population mean PG peak and trough concentrations range between 33–144 and 28–218 mg l−1 (peak) and 19–109 and 6–112 mg l−1 (trough) for paracetamol and phenobarbital formulations, respectively, depending on birth weight and age of the neonates. CONCLUSION A pharmacokinetic model was developed for PG co-administered with paracetamol or phenobarbital in neonates. As such, large variability in PG exposure may be expected in neonates which is dependent on birth weight and PNA. PMID:22536830

  15. Comparison of methanol and acetonitrile eluents for the quantitation of chelators specific to soft-metal ions by HPLC.

    PubMed

    Ogawa, Shinya; Yoshimura, Etsuro

    2012-11-15

    HPLC eluent systems employing acetonitrile and methanol were evaluated for the quantitation of glutathione (GSH) and phytochelatin (PC(n)), a family of peptides implicated in heavy-metal detoxification in higher plants. The detection system is based on the dequenching of copper(I)-bathocuproine disulfonate and is specific for soft-metal chelators. Although both elution systems yielded comparable analytical performance for each PC(n), the acetonitrile system had a lower sensitivity for GSH and a steadily increasing baseline. The inferior properties of the acetonitrile system may be due to complex formation between acetonitrile and Cu(I) ions. Both methods were applied to measure peptide levels in the primitive red alga Cyanidioschyzon merolae. Coefficients of variation (CVs) were less than 5%, except for GSH and PC(4) determinations in the acetonitrile system, in cases when CV values were found to be 8.8% and 6.3%, respectively. Recoveries were greater than 96%, except for GSH determination in the acetonitrile system, with a recovery of 84.4%; however, the concentration measured in the acetonitrile system did not differ from that measured in the methanol system at a significance level of 0.05. PMID:23153641

  16. Convenient treatment of acetonitrile-containing wastes using the tandem combination of nitrile hydratase and amidase-producing microorganisms.

    PubMed

    Kohyama, Erina; Yoshimura, Akihiro; Aoshima, Daisuke; Yoshida, Toyokazu; Kawamoto, Hiroyoshi; Nagasawa, Toru

    2006-09-01

    This study aimed to construct an acetonitrile-containing waste treatment process by using nitrile-degrading microorganisms. To degrade high concentrations of acetonitrile, the microorganisms were newly acquired from soil and water samples. Although no nitrilase-producing microorganisms were found to be capable of degrading high concentrations of acetonitrile, the resting cells of Rhodococcus pyridinivorans S85-2 containing nitrile hydratase could degrade acetonitrile at concentrations as high as 6 M. In addition, an amidase-producing bacterium, Brevundimonas diminuta AM10-C-1, of which the resting cells degraded 6 M acetamide, was isolated. The combination of R. pyridinivorans S85-2 and B. diminuta AM10-C-1 was tested for the conversion of acetonitrile into acetic acid. The resting cells of B. diminuta AM10-C-1 were added after the first conversion involving R. pyridinivorans S85-2. Through this tandem process, 6 M acetonitrile was converted to acetic acid at a conversion rate of >90% in 10 h. This concise procedure will be suitable for practical use in the treatment of acetonitrile-containing wastes on-site. PMID:16402166

  17. Diffusion-controlled reactions in supercritical CHF[sub 3] and CO[sub 2]/acetonitrile mixtures

    SciTech Connect

    Roberts, C.B.; Zhang, J.; Chateauneuf, J.E.; Brennecke, J.F. )

    1993-10-20

    We present results of the triplet-triplet annihilation (TTA) process of benzophenone (Ph[sub 2]C = O) and the self-termination reaction of benzyl radical (PhCH[sub 2]) to investigate the possibility of diffusion-controlled processes being hindered or enhanced in supercritical fluids (SCFs) or fluid mixtures. However, both reactions occur essentially at the diffusion-control limit in supercritical fluoroform (CHF[sub 3]) and carbon dioxide (CO[sub 2]) doped with 1 mol % acetonitrile (CH[sub 3]CN) when spin statistical factors are taken into account. The reaction kinetics were measured by laser flash photolysis at various pressures above the critical pressure along three isotherms. This study corroborates our earlier report of these reactions in supercritical CO[sub 2] and ethane (C[sub 2]H[sub 6]). In all of the fluids and fluid mixture, the locally higher density of the solvent around the solutes in no way enhances or slows the bimolecular annihilation or termination reaction. In addition, there is no evidence of enhanced solute-solute interaction. Finally, we studied the photocleavage of dibenzyl ketone (DBK) and the subsequent decarbonylation of the phenylacetyl radical (PhCH[sub 2]CO) and did not observe any enhanced cage effects or anomalous behavior due to the increased local density. 54 refs., 6 figs.

  18. Synthesis of biocompatible poly(ɛ-caprolactone)- block-poly(propylene adipate) copolymers appropriate for drug nanoencapsulation in the form of core-shell nanoparticles

    PubMed Central

    Nanaki, Stavroula G; Pantopoulos, Kostas; Bikiaris, Dimitrios N

    2011-01-01

    Poly(propylene adipate)-block-poly(ɛ-caprolactone) copolymers were synthesized using a combination of polycondensation and ring-opening polymerization of ɛ-caprolactone in the presence of poly(propylene adipate). Gel permeation chromatography was used for molecular weight determination, whereas hydrogen-1 nuclear magnetic resonance and carbon-13 nuclear magnetic resonance spectroscopy were employed for copolymer characterization and composition evaluation. The copolymers were found to be block while their composition was similar to the feeding ratio. They formed semicrystalline structures, while only poly(ɛ-caprolactone) formed crystals, as shown by wide angle X-ray diffraction. Differential scanning calorimetry data suggest that the melting point and heat of fusion of copolymers decreased by increasing the poly(propylene adipate) amount. The synthesized polymers exhibited low cytotoxicity and were used to encapsulate desferrioxamine, an iron-chelating drug. The desferrioxamine nanoparticles were self-assembled into core shell structures, had mean particle size <250 nm, and the drug remained in crystalline form. Further studies revealed that the dissolution rate was mainly related to the melting temperature, as well as to the degree of crystallinity of copolymers. PMID:22162656

  19. Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation.

    PubMed

    Herzberger, Jana; Niederer, Kerstin; Pohlit, Hannah; Seiwert, Jan; Worm, Matthias; Wurm, Frederik R; Frey, Holger

    2016-02-24

    The review summarizes current trends and developments in the polymerization of alkylene oxides in the last two decades since 1995, with a particular focus on the most important epoxide monomers ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO). Classical synthetic pathways, i.e., anionic polymerization, coordination polymerization, and cationic polymerization of epoxides (oxiranes), are briefly reviewed. The main focus of the review lies on more recent and in some cases metal-free methods for epoxide polymerization, i.e., the activated monomer strategy, the use of organocatalysts, such as N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) as well as phosphazene bases. In addition, the commercially relevant double-metal cyanide (DMC) catalyst systems are discussed. Besides the synthetic progress, new types of multifunctional linear PEG (mf-PEG) and PPO structures accessible by copolymerization of EO or PO with functional epoxide comonomers are presented as well as complex branched, hyperbranched, and dendrimer like polyethers. Amphiphilic block copolymers based on PEO and PPO (Poloxamers and Pluronics) and advances in the area of PEGylation as the most important bioconjugation strategy are also summarized. With the ever growing toolbox for epoxide polymerization, a "polyether universe" may be envisaged that in its structural diversity parallels the immense variety of structural options available for polymers based on vinyl monomers with a purely carbon-based backbone. PMID:26713458

  20. Propanal synthesis from aqueous propylene glycol/hydrogen peroxide on a Ru/alumina catalyst

    SciTech Connect

    Disselkamp, Robert S.; Harris, Benjamin D.; Patel, Jayshribe N.; Hart, Todd R.; Peden, Charles HF

    2008-05-01

    The conversion of polyol materials, including 1,2-diols, into higher commodity chemicals is actively being pursued by many researchers. Here we report the production of propanal from propylene glycol and hydrogen peroxide using a Ru/alumina catalyst. Experiments were conducted by adding up to four peroxide equivalents under steady-state reflux conditions at 371 K. The product propanal and its subsequent reaction product with substrate, 1,3-dioxolane-2-ethyl-4-methyl, was observed to be an intermediate achieving a maximum concentration of 3% of substrate. Buffering using Mg(OH)2 at pH~10 resulted in propanal formation, whereas buffering at similar pH using Na2HSO4 did not, from which we propose that magnesium acts as a promoter in the reaction. The mechanism appears to be a dehydration to enol, followed by rearrangement to product. Experiments utilizing Ru/carbon did not yield any propanol suggesting that the acidic sites of alumina aid the dehydration reaction. To our knowledge, this represents the first time hydrogen peroxide has been used in an alcohol dehydration reaction.

  1. A 1,2-propylene oxide sensor utilizing cataluminescence on CeO2 nanoparticles.

    PubMed

    Liu, Hongmei; Zhang, Yantu; Zhen, Yanzhong; Ma, Yuan; Zuo, Weiwei

    2014-12-01

    A simple and sensitive gas sensor was proposed for the determination of 1,2-propylene oxide (PO) based on its cataluminescence (CTL) by oxidation in the air on the surface of CeO2 nanoparticles. The luminescence characteristics and optimal conditions were investigated in detail. Under optimized conditions, the linear range of the CTL intensity versus the concentration of PO was 10-150 ppm, with a correlation coefficient (r) of 0.9974 and a limit of detection (S/N = 3) of 0.9 ppm. The relative standard deviation for 40 ppm PO was 1.2% (n = 7). There was no or only weak response to common foreign substances including acetone, formaldehyde, ethyl acetate, acetic acid, chloroform, propanol, carbon tetrachloride, ether and methanol. There was no significant change in the catalytic activity of the sensor for 100 h. The proposed method was simple and sensitive, with a potential of detecting PO in the environment and industry. PMID:24802092

  2. Immobilization of Rhodococcus rhodochrous BX2 (an acetonitrile-degrading bacterium) with biofilm-forming bacteria for wastewater treatment.

    PubMed

    Li, Chunyan; Li, Yue; Cheng, Xiaosong; Feng, Liping; Xi, Chuanwu; Zhang, Ying

    2013-03-01

    In this study, a unique biofilm consisting of three bacterial strains with high biofilm-forming capability (Bacillus subtilis E2, E3, and N4) and an acetonitrile-degrading bacterium (Rhodococcus rhodochrous BX2) was established for acetonitrile-containing wastewater treatment. The results indicated that this biofilm exhibited strong resistance to acetonitrile loading shock and displayed a typical spatial and structural heterogeneity and completely depleted the initial concentration of acetonitrile (800mgL(-1)) within 24h in a moving-bed-biofilm reactor (MBBR) after operation for 30days. The immobilization of BX2 cells in the biofilm was confirmed by PCR-DGGE. It has been demonstrated that biofilm-forming bacteria can promote the immobilization of contaminant-degrading bacteria in the biofilms and can subsequently improve the degradation of contaminants in wastewater. This approach offers a novel strategy for enhancing biological oxidation of toxic pollutants in wastewater. PMID:23376196

  3. Transparent Films from CO2‐Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing

    PubMed Central

    Subhani, Muhammad Afzal; Köhler, Burkhard; Gürtler, Christoph; Leitner, Walter

    2016-01-01

    Abstract Transparent films were prepared by cross‐linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO2, propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron‐acceptor and electron‐donor groups enables particularly facile UV‐ or redox‐initiated free‐radical curing. The resulting materials are transparent and highly interesting for coating applications. PMID:27028458

  4. FORMATION OF POLYKETONES IN IRRADIATED TOLUENE/PROPYLENE/NOX/AIR MIXTURES

    EPA Science Inventory

    A laboratory study was carried out to investigate the formation of polyketones in secondary organic aerosol from photooxidation of the aromatic hydrocarbon toluene, a major constituent of automobile exhaust. The laboratory experiments consisted of irradiating toluene/propylene...

  5. The History of Current State of the Art of Propylene Polymerization Catalysts.

    ERIC Educational Resources Information Center

    Goodall, Brian L.

    1986-01-01

    Outlines the development of the modern catalysts for propylene polymerization, considering the historical background; structure of titanium chloride catalysts; first-generation catalysts; cocatalysts; second-generation catalysts; catalysts morphology; and third-generation (supported catalysts). (JN)

  6. Strategies for the Hyperpolarization of Acetonitrile and Related Ligands by SABRE

    PubMed Central

    2014-01-01

    We report on a strategy for using SABRE (signal amplification by reversible exchange) for polarizing 1H and 13C nuclei of weakly interacting ligands which possess biologically relevant and nonaromatic motifs. We first demonstrate this via the polarization of acetonitrile, using Ir(IMes)(COD)Cl as the catalyst precursor, and confirm that the route to hyperpolarization transfer is via the J-coupling network. We extend this work to the polarization of propionitrile, benzylnitrile, benzonitrile, and trans-3-hexenedinitrile in order to assess its generality. In the 1H NMR spectrum, the signal for acetonitrile is enhanced 8-fold over its thermal counterpart when [Ir(H)2(IMes)(MeCN)3]+ is the catalyst. Upon addition of pyridine or pyridine-d5, the active catalyst changes to [Ir(H)2(IMes)(py)2(MeCN)]+ and the resulting acetonitrile 1H signal enhancement increases to 20- and 60-fold, respectively. In 13C NMR studies, polarization transfers optimally to the quaternary 13C nucleus of MeCN while the methyl 13C is hardly polarized. Transfer to 13C is shown to occur first via the 1H–1H coupling between the hydrides and the methyl protons and then via either the 2J or 1J couplings to the respective 13Cs, of which the 2J route is more efficient. These experimental results are rationalized through a theoretical treatment which shows excellent agreement with experiment. In the case of MeCN, longitudinal two-spin orders between pairs of 1H nuclei in the three-spin methyl group are created. Two-spin order states, between the 1H and 13C nuclei, are also created, and their existence is confirmed for Me13CN in both the 1H and 13C NMR spectra using the Only Parahydrogen Spectroscopy protocol. PMID:25539423

  7. Acetonitrile and N-Chloroacetamide Formation from the Reaction of Acetaldehyde and Monochloramine.

    PubMed

    Kimura, Susana Y; Vu, Trang Nha; Komaki, Yukako; Plewa, Michael J; Mariñas, Benito J

    2015-08-18

    Nitriles and amides are two classes of nitrogenous disinfection byproducts (DBPs) associated with chloramination that are more cytotoxic and genotoxic than regulated DBPs. Monochloramine reacts with acetaldehyde, a common ozone and free chlorine disinfection byproduct, to form 1-(chloroamino)ethanol. Equilibrium (K1) and forward and reverse rate (k1,k-1) constants for the reaction between initial reactants and 1-(chloroamino)ethanol were determined between 2 and 30 °C. Activation energies for k1 and k-1 were 3.04 and 45.2 kJ·mol(-1), respectively, and enthalpy change for K1 was -42.1 kJ·mol(-1). In parallel reactions, 1-(chloroamino)ethanol (1) slowly dehydrated (k2) to (chloroimino)ethane that further decomposed to acetonitrile and (2) was oxidized (k3) by monochloramine to produce N-chloroacetamide. Both reactions were acid/base catalyzed, and rate constants were characterized at 10, 18, and 25 °C. Modeling for drinking water distribution system conditions showed that N-chloroacetamide and acetonitrile concentrations were 5-9 times higher at pH 9.0 compared to 7.8. Furthermore, acetonitrile concentration was found to form 7-10 times higher than N-chloroacetamide under typical monochloramine and acetaldehyde concentrations. N-chloroacetamide cytotoxicity (LC50 = 1.78 × 10(-3) M) was comparable to dichloroacetamide and trichloroacetamide, but less potent than N,2-dichloroacetamide and chloroacetamide. While N-chloroacetamide was not found to be genotoxic, N,2-dichloroacetamide genotoxic potency (5.19 × 10(-3) M) was on the same order of magnitude as chloroacetamide and trichloroacetamide. PMID:26167888

  8. Tropospheric light alcohols, carbonyls, and acetonitrile: Concentrations in the southwestern United States and Henry's Law data

    NASA Astrophysics Data System (ADS)

    Snider, Jefferson R.; Dawson, G. A.

    1985-04-01

    Aliphatic alcohols (C1 - C4), aldehydes (C1 - C2) and ketones (C3 - C4) have been determined at Tucson, Arizona, and at two rural sites about 40 km distant. Acetonitrile was also measured at the rural sites. The method involved condensation sampling, condensate preconcentration, and gas chromatography. Henry's law coefficients were required for all components and were determined. Mean concentrations in Tucson were higher than those in the rural areas by factors typically between 2 and 8; urban formaldehyde was only slightly elevated. Mean alcohol concentrations ranged from 7.9 ppb (C1) to 0.12 ppb (C4) within the city and from 2.6 ppb (C1) to 0.06 ppb (C4) at the rural sites. Acetone was found at 12 ppb in the city and 2.8 ppb at the rural sites. Concentrations of butanone were a factor of 5 lower. Acetaldehyde, at 23 ppb (city) and 6.9 ppb (rural), far exceeded formaldehyde concentrations (1.8 ppb in the city, and 1.5 ppb at the rural sites). Acetonitrile was found at the rural sites at a mean concentration of 60 ppt. A dimensionless Henry's law coefficient (mol L-1 of liquid/mol L-1 of vapor) was suprisingly similar for the alcohols at 0°C, ranging between 2×104 and 3.4×104 (900-1500 mol L-1 atm-1) the ketones were a factor of 10 lower. For acetaldehyde the coefficient was 1.7×103 (76 mol L-1 atm-1) and for acetonitrile 3.7×103 (165 mol L-1 atm-1). Concentrations of oxygenated organics in the condensates and in precipitation were compared; it was tentatively concluded that concentration differences of the carbonyls were consistent with these species being produced within the cloud, for example, by aqueous photochemistry.

  9. Ligand sensitized luminescence of uranyl by benzoic acid in acetonitrile medium: A new luminescent uranyl benzoate specie

    NASA Astrophysics Data System (ADS)

    Kumar, Satendra; Maji, S.; Joseph, M.; Sankaran, K.

    2015-03-01

    Benzoic acid (BA) is shown to sensitize and enhance the luminescence of uranyl ion in acetonitrile medium. Luminescence spectra and especially UV-Vis spectroscopy studies reveal the formation of tri benzoate complex of uranyl i.e. [UO2(C6H5COO)3]- which is highly luminescent. In particular, three sharp bands at 431, 443, 461 nm of absorption spectra provides evidence for tri benzoate specie of uranyl in acetonitrile medium. The luminescence lifetime of uranyl in this complex is 68 μs which is much more compared to the lifetime of uncomplexed uranyl (20 μs) in acetonitrile medium. In contrary to aqueous medium where uranyl benzoate forms 1:1 and 1:2 species, spectroscopic data reveal formation of 1:3 complex in acetonitrile medium. Addition of water to acetonitrile results in decrease of luminescence intensity of this specie and the luminescence features implode at 20% (v/v) of water content. For the first time, to the best of our knowledge, the existence of [UO2(C6H5COO)3]- specie in acetonitrile is reported. Mechanism of luminescence enhancement is discussed.

  10. Ligand sensitized luminescence of uranyl by benzoic acid in acetonitrile medium: a new luminescent uranyl benzoate specie.

    PubMed

    Kumar, Satendra; Maji, S; Joseph, M; Sankaran, K

    2015-03-01

    Benzoic acid (BA) is shown to sensitize and enhance the luminescence of uranyl ion in acetonitrile medium. Luminescence spectra and especially UV-Vis spectroscopy studies reveal the formation of tri benzoate complex of uranyl i.e. [UO2(C6H5COO)3](-) which is highly luminescent. In particular, three sharp bands at 431, 443, 461nm of absorption spectra provides evidence for tri benzoate specie of uranyl in acetonitrile medium. The luminescence lifetime of uranyl in this complex is 68μs which is much more compared to the lifetime of uncomplexed uranyl (20μs) in acetonitrile medium. In contrary to aqueous medium where uranyl benzoate forms 1:1 and 1:2 species, spectroscopic data reveal formation of 1:3 complex in acetonitrile medium. Addition of water to acetonitrile results in decrease of luminescence intensity of this specie and the luminescence features implode at 20% (v/v) of water content. For the first time, to the best of our knowledge, the existence of [UO2(C6H5COO)3](-) specie in acetonitrile is reported. Mechanism of luminescence enhancement is discussed. PMID:25528510

  11. Direct epoxidation of propylene over stabilized Cu(+) surface sites on titanium-modified Cu2O.

    PubMed

    Yang, Xiaofang; Kattel, Shyam; Xiong, Ke; Mudiyanselage, Kumudu; Rykov, Sergei; Senanayake, Sanjaya D; Rodriguez, José A; Liu, Ping; Stacchiola, Dario J; Chen, Jingguang G

    2015-10-01

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate that by generating highly dispersed and stabilized Cu(+) active sites in a TiCuOx mixed oxide the epoxidation selectivity can be tuned. The TiCuOx surface anchors the key surface intermediate, an oxametallacycle, leading to higher selectivity for epoxidation of propylene. PMID:26215635

  12. Toxicity of ethylene glycol, diethylene glycol, and propylene glycol to human cells in culture

    SciTech Connect

    Mochida, K.; Gomyoda, M.

    1987-01-01

    Tissue culture toxicity of various alcohols has been reported by Dillingham who used mouse L cells and Koerker who used mouse neuroblastoma cells. The toxicity of various polyhydric alcohols (ethylene glycol, diethylene glycol and propylene glycol) has apparently not been determined, under conditions of culture. The authors report the toxicity of ethylene glycol, diethylene glycol and propylene glycol and KB cells and the results are compared with previous data obtained using their cell culture system.

  13. Analysis of automobile radiator performance with ethylene glycol/water and propylene glycol/water coolants

    SciTech Connect

    Gollin, M.; Bjork, D.

    1996-12-31

    The heat transfer and hydraulic performance of the following coolants was examined in five automobile radiators in a wind tunnel: 100% water; 100% propylene glycol; 70/30 propylene glycol/water (volume); 50/50 propylene glycol/water (volume); 70/30 ethylene glycol/water (volume); 50/50 ethylene glycol water (volume). The results of these studies are presented to demonstrate the relative performance of these coolant mixtures in terms of heat transfer, coolant pressure drop and radiator effectiveness for a range of coolant and air flowrates. It is concluded that the most effective of the coolants in transferring heat in the test radiators was water, followed by 50/50 ethylene glycol/water, 50/50 propylene glycol/water, 70/30 ethylene glycol/water, 70/30 propylene glycol and, finally, 100% propylene glycol. There will be a negligible differences between the performance of a radiator using a 50/50 propylene glycol/water coolant and a 50/50 ethylene glycol/water coolant. It is estimated that, with 50/50 propylene glycol coolant replacing 50/50 ethylene glycol/water, the temperature of the coolant throughout the cooling loop will increase by approximately 5%. The effect that the flow regime (fully turbulent/transition/laminar) has upon the performance of a given radiator/coolant combination was found to be significant. The design of the coolant passages in radiators can affect the onset of fully turbulent flow in the coolant passages in a radiator.

  14. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    DOE PAGESBeta

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  15. A rapid analysis of plasma/serum ethylene and propylene glycol by headspace gas chromatography.

    PubMed

    Ehlers, Alexandra; Morris, Cory; Krasowski, Matthew D

    2013-12-01

    A rapid headspace-gas chromatography (HS-GC) method was developed for the analysis of ethylene glycol and propylene glycol in plasma and serum specimens using 1,3-propanediol as the internal standard. The method employed a single-step derivitization using phenylboronic acid, was linear to 200 mg/dL and had a lower limit of quantitation of 1 mg/dL suitable for clinical analyses. The analytical method described allows for laboratories with HS-GC instrumentation to analyze ethanol, methanol, isopropanol, ethylene glycol, and propylene glycol on a single instrument with rapid switch-over from alcohols to glycols analysis. In addition to the novel HS-GC method, a retrospective analysis of patient specimens containing ethylene glycol and propylene glycol was also described. A total of 36 patients ingested ethylene glycol, including 3 patients who presented with two separate admissions for ethylene glycol toxicity. Laboratory studies on presentation to hospital for these patients showed both osmolal and anion gap in 13 patients, osmolal but not anion gap in 13 patients, anion but not osmolal gap in 8 patients, and 1 patient with neither an osmolal nor anion gap. Acidosis on arterial blood gas was present in 13 cases. Only one fatality was seen; this was a patient with initial serum ethylene glycol concentration of 1282 mg/dL who died on third day of hospitalization. Propylene glycol was common in patients being managed for toxic ingestions, and was often attributed to iatrogenic administration of propylene glycol-containing medications such as activated charcoal and intravenous lorazepam. In six patients, propylene glycol contributed to an abnormally high osmolal gap. The common presence of propylene glycol in hospitalized patients emphasizes the importance of being able to identify both ethylene glycol and propylene glycol by chromatographic methods. PMID:23741644

  16. Density Functional Studies on the Complexation and Spectroscopy of Uranyl Ligated with Acetonitrile and Acetone Derivatives

    SciTech Connect

    Schoendorff, George E.; Windus, Theresa L.; De Jong, Wibe A.

    2009-12-12

    The coordination of nitrile (acetonitrile, propionitrile, and benzonitrile) and carbonyl (formaldehyde, ethanal, and acetone) ligands to the uranyl dication (UO22+) has been examined using density functional theory (DFT) utilizing relativistic effective core potentials (RECPs). Complexes containing up to six ligands have been modeled for all ligands except formaldehyde, for which no minimum could be found. A comparison of relative binding energies indicates that five coordinate complexes are predominant while a six coordinate complex involving propionitrile ligands might be possible. Additionally, the relative binding energy and the weakening of the uranyl bond is related to the size of the ligand and, in general, nitriles bind more strongly to uranyl than carbonyls.

  17. Elemental step thermodynamics of various analogues of indazolium alkaloids to obtaining hydride in acetonitrile.

    PubMed

    Lei, Nan-Ping; Fu, Yan-Hua; Zhu, Xiao-Qing

    2015-12-21

    A series of analogues of indazolium alkaloids were designed and synthesized. The thermodynamic driving forces of the 6 elemental steps for the analogues of indazolium alkaloids to obtain hydride in acetonitrile were determined using an isothermal titration calorimeter (ITC) and electrochemical methods, respectively. The effects of molecular structure and substituents on the thermodynamic driving forces of the 6 steps were examined. Meanwhile, the oxidation mechanism of NADH coenzyme by indazolium alkaloids was examined using the chemical mimic method. The result shows that the oxidation of NADH coenzyme by indazolium alkaloids in vivo takes place by one-step concerted hydride transfer mechanism. PMID:26451708

  18. Possible stabilization of the tetravalent oxidation state of berkelium and californium in acetonitrile with triphenylarsine oxide

    SciTech Connect

    Payne, G.F.; Peterson, J.R.

    1987-01-01

    It appears that we may have prepared Bk(IV) nitrate.nTPAs0 and Bk(IV) perchlorate.nTPAs0 complexes which formed the corresponding Cf(IV) complexes through the beta decay of Bk-249. Definitive proof should come from similar experiments with quantities of Bk-249 large enough to allow spectrophotometric detection of the characteristic f..-->..f transitions in these berkelium and californium species. It is clear, however, that TPAs0 and acetonitrile can play a pivotal role in the stabilization of lanact(IV) species.

  19. Comparison of Thermal Performance Characteristics of Ammonia and Propylene Loop Heat Pipes

    NASA Technical Reports Server (NTRS)

    Kaya, Tarik; Baker, Charles; Ku, Jentung

    2000-01-01

    In this paper, experimental work performed on a breadboard Loop Heat Pipe (LHP) is presented. The test article was built by DCI for the Geoscience Laser Altimeter System (GLAS) instrument on the ICESat spacecraft. The thermal system requirements of GLAS have shown that ammonia cannot be used as the working fluid in this LHP because GLAS radiators could cool to well below the freezing point of ammonia. As a result, propylene was proposed as an alternative LHP working fluid since it has a lower freezing point than ammonia. Both working fluids were tested in the same LHP following a similar test plan in ambient conditions. The thermal performance characteristics of ammonia and propylene LHP's were then compared. In general, the propylene LHP required slightly less startup superheat 5nd less control heater power than the ammonia LHP, The thermal conductance values for the propylene LHP were also lower than the ammonia LHP. Later, the propylene LHP was tested in a thermal vacuum chamber. These tests demonstrated that propylene could meet the GLAS thermal design requirements. Design guidelines were proposed for the next flight-like Development Model (DM) LHP for thermal control of the GLAS instrument.

  20. Biodegradation of propylene glycol and associated hydrodynamic effects in sand.

    PubMed

    Bielefeldt, Angela R; Illangasekare, Tissa; Uttecht, Megan; LaPlante, Rosanna

    2002-04-01

    At airports around the world, propylene glycol (PG) based fluids are used to de-ice aircraft for safe operation. PG removal was investigated in 15-cm deep saturated sand columns. Greater than 99% PG biodegradation was achieved for all flow rates and loading conditions tested, which decreased the hydraulic conductivity of the sand by 1-3 orders of magnitude until a steady-state minimum was reached. Under constant loading at 120 mg PG/d for 15-30 d, the hydraulic conductivity (K) decreased by 2-2.5 orders of magnitude when the average linear velocity of the water was 4.9-1.4 cm/h. Variable PG loading in recirculation tests resulted in slower conductivity declines and lower final steady-state conductivity than constant PG feeding. After significant sand plugging, endogenous periods of time without PG resulted in significant but partial recovery of the original conductivity. Biomass growth also increased the dispersivity of the sand. PMID:12044070

  1. Vibrational Relaxation of the Aqueous Proton in Acetonitrile: Ultrafast Cluster Cooling and Vibrational Predissociation.

    PubMed

    Ottosson, N; Liu, L; Bakker, H J

    2016-07-28

    We study the ultrafast O-H stretch vibrational relaxation dynamics of protonated water clusters embedded in a matrix of deuterated acetonitrile, using polarization-resolved mid-IR femtosecond spectroscopy. The clusters are produced by mixing triflic (trifluoromethanesulfonic) acid and H2O in molar ratios of 1:1, 1:2, and 1:3, thus varying the degree of hydration of the proton. At all hydration levels the excited O-H stretch vibration of the hydrated proton shows an ultrafast vibrational relaxation with a time constant T1 < 100 fs, leading to an ultrafast local heating of the protonated water cluster. This excess thermal energy, initially highly localized to the region of the excited proton, first re-distributes over the aqueous cluster and then dissipates into the surrounding acetonitrile matrix. For clusters with a triflic acid to H2O ratio of 1:3 these processes occur with time constants of 320 ± 20 fs and 1.4 ± 0.1 ps, respectively. The cooling of the clusters reveals a long-living, underlying transient absorption change with high anisotropy. We argue that this feature stems from the vibrational predissociation of a small fraction of the proton hydration structures, directly following the ultrafast infrared excitation. PMID:27333302

  2. Pediatric cyanide intoxication and death from an acetonitrile-containing cosmetic

    SciTech Connect

    Caravati, E.M.; Litovitz, T.L. )

    1988-12-16

    Two cases of pediatric accidental ingestion of an acetonitrile-containing cosmetic are reported. One of the children, a 16-month-old boy, was found dead in bed the morning after ingesting the product. No therapy had been undertaken, as the product was mistakenly assumed to be an acetone-containing nail polish remover. The second child, a 2-year-old boy, experienced signs of severe cyanide poisoning, but survived with vigorous supportive care. Both children had blood cyanide levels in the potentially lethal range. The observed delayed onset of severe toxic reactions supports the proposed mechanism of acetonitrile conversion to inorganic cyanide via hepatic microsomal enzymes. Physicians and poison centers should be alerted to the existence of this highly toxic product, sold for removal of sculptured nails and likely to be confused with the less toxic acetone-containing nail polish removers. The authors urge regulatory agencies to reconsider the wisdom of marketing a cosmetic that poses such an extreme health hazard.

  3. Pediatric cyanide intoxication and death from an acetonitrile-containing cosmetic.

    PubMed

    Caravati, E M; Litovitz, T L

    1988-12-16

    Two cases of pediatric accidental ingestion of an acetonitrile-containing cosmetic are reported. One of the children, a 16-month-old boy, was found dead in bed the morning after ingesting the product. No therapy had been undertaken, as the product was mistakenly assumed to be an acetone-containing nail polish remover. The second child, a 2-year-old boy, experienced signs of severe cyanide poisoning, but survived with vigorous supportive care. Both children had blood cyanide levels in the potentially lethal range. The observed delayed onset of severe toxic reactions supports the proposed mechanism of acetonitrile conversion to inorganic cyanide via hepatic microsomal enzymes. Physicians and poison centers should be alerted to the existence of this highly toxic product, sold for removal of sculptured nails and likely to be confused with the less toxic acetone-containing nail polish removers. We urge regulatory agencies to reconsider the wisdom of marketing a cosmetic that poses such an extreme health hazard. PMID:3062198

  4. A tetranuclear cadmium(II) complex based on the 2-(quinolin-8-yloxy)acetonitrile ligand.

    PubMed

    Liu, Ming-Liang; Ye, Qiong

    2013-01-01

    The hydrothermal reaction of 2-(quinolin-8-yloxy)acetonitrile and Cd(ClO(4))(2) yielded the noncentrosymmetric coordination complex tetrakis[μ-2-(quinolin-8-yloxy)acetato]tetrakis[μ-2-(quinolin-8-yloxy)acetonitrile]tetracadmium tetrakis(perchlorate) dihydrate, [Cd(4)(C(11)H(8)NO(3))(4)(C(11)H(8)N(2)O)(4)](ClO(4))(4)·2H(2)O. The local coordination environment around the Cd(II) cation can be best described as a capped octahedron defined by two N atoms and five O atoms from three ligands. The Cd(II) cations are linked by the ligands with Cd-O-Cd and Cd-O-C-C-O-Cd bridges, forming tetranuclear units, there being two independent tertranuclear units in the structure. The fourfold rotoinversion centre sits at the centre of each Cd(4) core. The two perchlorate anions in the asymmetric unit are linked by the water molecule through O-H...O hydrogen bonds. PMID:23282905

  5. The interhemispheric distribution and the budget of acetonitrile in the troposphere

    NASA Astrophysics Data System (ADS)

    Hamm, Stephan; Warneck, Peter

    1990-11-01

    Gas chromatography in conjunction with a thermionic nitrogen-specific detector was used to determine mixing ratios of acetonitrile in air samples collected in Europe and over the Atlantic Ocean. In the city of Mainz, values of the order of 340 pptv were observed with large variations indicating the vicinity of sources. In the rural community of Deuselbach the average mixing ratio was 147±28 pptv; over the North Sea the range was 65-196 pptv depending on wind direction, with the lowest values occurring for northerly winds from the open ocean. The distribution of CH3 CN with geographic latitude over the Atlantic Ocean was explored between 30°S and 50°N on board R/V Polarstern during the cruise ANT V/5 in March-April 1987. Over the open ocean, maximum mixing ratios were observed near 4°S with values of 175 pptv. At latitudes near 30°S the mixing ratio averaged 90.4 pptv, whereas at 30°N the average was 52.1 pptv. The lowest mixing ratios of 21 pptv were found near 50°N. The tropical maximum is attributed to the advection with the trade winds of continental air from Africa, enriched with acetonitrile from biomass burning. The mixing ratios north and south of the maximum correlate well with the surface temperature of seawater, indicating a gas-liquid equilibrium for CH3 CN dissolved in seawater. From the observations and with the further assumption that CH3 CN is vertically well mixed, its total mass content in the troposphere was estimated as 0.37-0.57 Tg. Global emission rates for various sources were estimated as follows: automobiles 0.27 Tg/year, oil-fired power stations 0.0035 Tg/year, and biomass burning 0.80 Tg/year. The total estimated source strength is 1.1±0.5 Tg/year. The tropospheric residence time of acetonitrile was calculated from these data as 0.23-0.90 year with a probable value of 0.45 year. Wet precipitation and reaction with OH radicals are known sinks for tropospheric CH3 CN, but they can take up only 30% of the global emission rate. We

  6. Developing synthesis techniques for zeolitic-imidazolate framework membranes for high resolution propylene/propane separation

    NASA Astrophysics Data System (ADS)

    Kwon, Hyuk Taek

    Propylene/propane separation is one of the most challenging separations, currently achieved by energy-intensive cryogenic distillation. Despite the great potentials for energy-efficient membrane-based propylene/propane separation processes, no commercial membranes are available due to the limitations (i.e., low selectivity) of current polymeric materials. Zeolitic imidazolate frameworks (ZIFs) are promising membrane materials primarily due to their well-defined ultra-micropores with controllable surface chemistry along with their relatively high thermal/chemical stabilities. In particular, ZIF-8 with the effective aperture size of ~ 4.0 A has been shown very promising for propylene/propane separation. Despite the extensive research on ZIF-8 membranes, only a few of ZIF-8 membranes have displayed good propylene/propane separation performances presumably due to the challenges of controlling the microstructures of polycrystalline membranes. Since the membrane microstructures are greatly influenced by processing techniques, it is critically important to develop new techniques. In this dissertation, three state-of-the-art ZIF membrane synthesis techniques are developed. The first is a one-step in-situ synthesis technique based on the concept of counter diffusion. The technique enabled us to obtain highly propylene selective ZIF-8 membranes in less than a couple of hours with exceptional mechanical strength. Most importantly, due to the nature of the counter-diffusion concept, the new method offered unique opportunities such as healing defective membranes (i.e., poorly-intergrown) as well as significantly reducing the consumption of costly ligands and organic solvents. The second is a microwave-assisted seeding technique. Using this new seeding technique, we were able to prepare seeded supports with a high packing density in a couple of minutes, which subsequently grown into highly propylene-selective ZIF-8 membranes with an average propylene/propane selectivity of ~40

  7. An Analysis of the Rotational Spectrum of Acetonitrile (CH_3CN) in Excited Vibrational States

    NASA Astrophysics Data System (ADS)

    Neese, Christopher F.; McMillan, James; Fortman, Sarah; De Lucia, Frank C.

    2014-06-01

    Acetonitrile (CH_3CN) is a well-known interstellar molecule whose vibrationally excited states need to be accounted for in searches for new molecules in the interstellar medium. To help catalog such `weed' molecules, we have developed a technique that involves recording complete spectra over a range of astrophysically significant temperatures. With such a data set, we can experimentally measure the line strengths and lower state energies of unassigned lines in the spectrum. In this talk we will present the ongoing analysis of complete temperature resolved spectra in the 215-265 GHz and 570-650 GHz regions. We have been able to assign many vibrationally hot lines from this data and a room temperature data set spanning 165-700 GHz. To date, we have assigned lines from most of the vibrational states below ν_6 at 1448 wn.

  8. Photon emission via surface state at the gold/acetonitrile solution interface

    SciTech Connect

    Uosaki, Kohei; Murakoshi, Kei; Kita, Hideaki )

    1991-01-24

    The emission of light caused by an electron-transfer reaction at a gold electrode in acetonitrile solution containing one of three redox species (benzophenone, trans-stilbene, and benzonitrile) with different redox potentials was studied. The high-energy threshold of the spectrum decreases linearly as the potential of the gold electrode becomes more negative. The peak position with respect to the high-energy threshold of the spectrum varies with electrode potential and is not affected by the redox potential of the electron injection species at the same electrode potential. The emission efficiency also depends on the potential. From these results, the authors proposed that the emission is due to a charge-transfer reaction inverse photoemission (CTRIP) process that takes place via a surface state.

  9. Isolation and identification of (3-methoxyphenyl)acetonitrile as a phytotoxin from meadowfoam (Limnanthes alba) seedmeal.

    PubMed

    Vaughn, S F; Boydston, R A; Mallory-Smith, C A

    1996-10-01

    Ethyl ether, ethanol, and water extracts of meadowfoam (Limnanthes alba Hartweg ex. Benth.) seedmeal were prepared and bioassayed against velvetleaf (Abutilon theophrasti Medicus) and wheat (Triticum aestivum L. "Cardinal"). Both the ethyl ether and ethanol fractions, but not the water extract, inhibited velvetleaf and wheat radicle elongation. Fractionation of the extracts indicated that (3-methoxyphenyl)acetonitrile (3-MPAN) was the active compound from both extracts, comprising >97% of the active ethanol fraction. 3-Methoxybenzyl isothiocyanate, which had been previously shown to be the major breakdown product of glucolimnanthin, the majorL. alba glucosinolate, was not detected in either extract. Radicle elongation of velvetleaf and wheat were inhibited by 3-MPAN with I50 (the concentration required to inhibit growth by 50%) values of approximately 4 × 10(-4) M (velvetleaf) and 7×10(-4) M (wheat). PMID:24227117

  10. The biochemical pathway for the breakdown of methyl cyanide (acetonitrile) in bacteria.

    PubMed Central

    Firmin, J L; Gray, D O

    1976-01-01

    [2-14C]Methyl cyanide (acetonitrile) is metabolized to citrate, succinate, fumarate, malate, glutamate, pyrrolidonecarboxylic acid and aspartate. Non-radioactive acetamide and acetate compete with 14C from methyl cyanide, and [2-14C]acetate and [2-14C]methyl cyanide are metabolized at similar rates, giving identical products. This evidence, combined with the inhibitory effect of fluoroacetate and arsenite on methyl cyanide metabolism, indicates that the pathway is: methyl cyanide leads to acetamide leads to acetate leads to tricarboxylic acid-cycle intermediates. The pathway was investigated in a species of Pseudomonas (group III; N.C.I.B. 10477), but comparison of labelling patterns suggests that it also exists in several higher plants. PMID:985423

  11. Electrolyte Solvation and Ionic Association. VI. Acetonitrile-Lithium Salt Mixtures. Highly Associated Salts Revisited

    SciTech Connect

    Borodin, Oleg; Han, Sang D.; Daubert, James S.; Seo, D. M.; Yun, Sung-Hyun; Henderson, Wesley A.

    2015-01-14

    Molecular dynamics (MD) simulations of acetonitrile (AN) mixtures with LiBF4, LiCF3SO3 and LiCF3CO2 provide extensive details about the molecular- and mesoscale-level solution interactions and thus explanations as to why these electrolytes have very different thermal phase behavior and electrochemical/physicochemical properties. The simulation results are in full accord with a previous experimental study of these (AN)n-LiX electrolytes. This computational study reveals how the structure of the anions strongly influences the ionic association tendency of the ions, the manner in which the aggregate solvates assemble in solution and the length of time in which the anions remain coordinated to the Li+ cations in the solvates which result in dramatic variations in the transport properties of the electrolytes.

  12. The response of Paracoccus sp. SKG to acetonitrile-induced oxidative stress.

    PubMed

    Kirankumar, B; Guruprasad, B Kulkarni; Santoshkumar, M; Anand, S Nayak; Karegoudar, T B

    2013-11-01

    Organic solvents enhance intracellular oxidative stress and induce various physiological responses in bacteria. The study shows the morphological changes in Paracoccus sp. SKG when exposed to higher concentrations of acetonitrile, which alter the composition of the membrane fatty acid that accompanies the increase in K(+) efflux. This enhances the oxidative stress with greater activities of catalase and super oxide dismutase (SOD). The increased oxidative stress results in the generation of free radicals, which was confirmed by electron paramagnetic resonance (EPR) studies. The free radical scavenging activities were measured by ABTS and DPPH to understand the non-enzymatic defensive system during oxidative stress. The studies demonstrate the increase in free radicals in association with enzymatic and non-enzymatic defense systems under solvent stress. PMID:24092001

  13. Heteroepitaxially grown zeolitic imidazolate framework membranes with unprecedented propylene/propane separation performances.

    PubMed

    Kwon, Hyuk Taek; Jeong, Hae-Kwon; Lee, Albert S; An, He Seong; Lee, Jong Suk

    2015-09-30

    Propylene/propane separation is one of the most challenging separations, currently achieved by energy-intensive cryogenic distillation. Despite the great potential for energy-efficient membrane-based separations, no commercial membranes are currently available due to the limitations of current polymeric materials. Zeolitic imidazolate framework, ZIF-8, with the effective aperture size of ∼4.0 Å, has been shown to be very promising for propylene/propane separation. Despite the extensive research on ZIF-8 membranes, only a few reported ZIF-8 membranes have displayed good propylene/propane separation performances presumably due to the challenges of controlling the microstructures of polycrystalline membranes. Here we report the first well-intergrown membranes of ZIF-67 (Co-substituted ZIF-8) by heteroepitaxially growing ZIF-67 on ZIF-8 seed layers. The ZIF-67 membranes exhibited impressively high propylene/propane separation capabilities. Furthermore, when a tertiary growth of ZIF-8 layers was applied to heteroepitaxially grown ZIF-67 membranes, the membranes exhibited unprecedentedly high propylene/propane separation factors of ∼200 possibly due to enhanced grain boundary structure. PMID:26364888

  14. New method for the photo-chemiluminometric determination of benzoylurea insecticides based on acetonitrile chemiluminescence.

    PubMed

    Gil García, M D; Martínez Galera, M; Santiago Valverde, R

    2007-03-01

    The viability of tandem photochemical reaction-chemiluminescence detection has been studied for the determination of five benzoylurea insecticides, namely, diflubenzuron, triflumuron, hexaflumuron, lufenuron and flufenoxuron. The 'on-line' photochemical reaction of benzoylurea pesticides provides an enhanced chemiluminescence response of the pesticides during their oxidation by potassium hexacyanoferrate(III) and sodium hydroxide, whose signal increases with the percentage of acetonitrile in the reaction medium. The determination was performed using a photoreactor consisting of a PFA (perfluoroalkoxy) tube reactor coil (5 mx1.6-mm O.D. and 0.8-mm I.D.) and an 8-W xenon lamp. As the yield of the photoderivatization process and the chemiluminescent signals depend on the percentage of acetonitrile, the chromatographic column (a Gemini C18, Phenomenex 150 mmx4.6 mm, 5-microm particle size) was chosen with the aim of using high percentages of this organic solvent in the mobile phase. Previous studies showed that the rate of the chemiluminescent reaction was very fast. Therefore, a modification was carried out in the detector in order to mix the analytes and reactants as near as possible to the measure cell. The optimised method was validated with respect to linearity, precision, limits of detection and quantification accuracy. Under the optimised conditions, linear working range extends three orders of magnitude with the relative standard deviation of intra-day precision below 10% and detection limits between 0.012 and 0.18 microg mL-1, according to the compound. The proposed method has been successfully applied to the determination of benzoylureas in cucumber with good results. PMID:17205265

  15. Heat sterilization of bioindicators in propylene glycol and propylene glycol-water mixtures: arrhenius equation, thermodynamic data, and Z values.

    PubMed

    Philipp, B; Sucker, H

    1990-12-01

    Our interest in calculating the thermodynamic data by means of the Arrhenius equation was based on two observation: (a) the thermal death time increases considerably when the bioindicators Bacillus subtilis var. niger and Bacillus stearothermophilus are sterilized in nonaqueous hydrophilic solutions as found in propylene glycol (PG) with low water concentrations; and (b) the inactivation kinetics of Bac. stearothermophilus does not follow a first-order reaction. The frequency factor A and the entropy of activation delta S* have the highest values in water and the lowest value in PG; delta S* for Bac. stearothermophilus in water is 812 J/mol K; however, in PG it is -9.6 J/mol K. A good correlation between delta S* and the enthalpy delta H* is found, indicating possible protein denaturation during thermal inactivation. The moderate positive and negative delta S* values in PG and PG with low water concentrations might be explained by (a) rigid conformation of proteins due to stabilization and (b) slow reaction, making the complex a less probable structure, when the activated complex is built only under considerable rearrangement of the structure of the reactant molecules. The opposite was observed with the Z and Z* values, the latter being defined as Z values of nonlogarithmic survival curves. The Z values increase with increasing concentrations of PG, i.e., for Bac. subtilis of Z = 8 degrees C in water up to Z = 23 degrees C in PG and for Bac. stearothermophilus of Z = 6 degrees C up to Z* = 27 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2128895

  16. Isotherm parameters and intraparticle mass transfer kinetics on molecularly imprinted polymers in acetonitrile/buffer mobile phases

    SciTech Connect

    Kim, Hyunjung; Kaczmarski, Krzysztof; Guiochon, Georges A

    2006-03-01

    The equilibrium isotherm and the intraparticle mass transfer kinetics of the enantiomers of the template were investigated on an Fmoc-L-tryptophan (Fmoc-L-Trp) imprinted polymer at different pHs and water concentrations in acetonitrile/aqueous buffer mobile phases. The equilibrium isotherm data were measured using frontal analysis at 25 {+-} 2 C. The adsorption energy distribution was found to be trimodal, with narrow modes. Consistent with this distribution, the adsorption data were modeled using a tri-Langmuir isotherm equation and the best estimates of the isotherm parameters were determined. The intraparticle mass transfer parameters were derived by comparing the profiles of experimental overloaded bands and the profiles calculated using the isotherm model and the lumped pore diffusion (POR) model of chromatography. These results showed that different adsorption and mass transfer mechanisms exist in mobile phases made of acetonitrile/aqueous buffer and of acetonitrile/acetic acid solutions.

  17. Multiresidue pesticide analysis of ginseng powders using acetonitrile- or acetone-based extraction, solid-phase extraction cleanup, and gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS).

    PubMed

    Wong, Jon W; Zhang, Kai; Tech, Katherine; Hayward, Douglas G; Krynitsky, Alexander J; Cassias, Irene; Schenck, Frank J; Banerjee, Kaushik; Dasgupta, Soma; Brown, Don

    2010-05-26

    A multiresidue method for the analysis of 168 pesticides in dried powdered ginseng has been developed using acetonitrile or acetone mixture (acetone/cyclohexane/ethyl acetate, 2:1:1 v/v/v) extraction, solid-phase extraction (SPE) cleanup with octyl-bonded silica (C(8)), graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, and capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). The geometric mean limits of quantitation (LOQs) were 53 and 6 microg/kg for the acetonitrile extraction and 48 and 7 microg/kg for the acetone-based extraction for GC-MS/SIM and GC-MS/MS, respectively. Mean percent recoveries and standard deviations from the ginseng fortified at 25, 100, and 500 microg/kg using GC-MS/SIM were 87 +/- 10, 88 +/- 8, and 86 +/- 10% from acetonitrile extracts and 88 +/- 13, 88 +/- 12, and 88 +/- 14% from acetone mixture extracts, respectively. The mean percent recoveries from the ginseng at the 25, 100, and 500 microg/kg levels using GC-MS/MS were 83 +/- 19, 90 +/- 13, and 89 +/- 11% from acetonitrile extracts and 98 +/- 20, 91 +/- 13, and 88 +/- 14% from acetone extracts, respectively. Twelve dried ginseng products were found to contain one or more of the following pesticides and their metabolites: BHCs (benzene hexachlorides, alpha-, beta-, gamma-, and delta-), chlorothalonil, chlorpyrifos, DDT (dichlorodiphenyl trichloroethane), dacthal, diazinon, iprodione, quintozene, and procymidone ranging from <1 to >4000 microg/kg. No significant differences were found between the two extraction solvents, and GC-MS/MS was found to be more specific and sensitive than GC-MS/SIM. The procedures described were shown to be effective in screening, identifying, confirming, and quantitating pesticides in commercial ginseng products. PMID:20225896

  18. Preparation and Thermo-Physical Properties of Fe2O3-Propylene Glycol Nanofluids.

    PubMed

    Shylaja, A; Manikandan, S; Suganthi, K S; Rajan, K S

    2015-02-01

    Iron oxide (Fe2O3) nanoparticles were prepared from ferric chloride and ferrous sulphate by precipitation reaction. Fe2O3-propylene glycol nanofluid was prepared by dispersing Fe2O3 nanoparticles in propylene glycol through stirred bead milling, shear homogenization and probe ultrasonication. The nanofluid was characterized through measurement of viscosity, particle size distribution and thermal conductivity. The interactions between Fe2O3 nanoparticles and propylene glycol on the nanoparticle surfaces lead to reduction in viscosity, the magnitude of which increases with nanoparticle concentration (0-2 vol%) at room temperature. The thermal conductivity enhancement for 2 vol% nanofluid was about 21% at room temperature, with liquid layering being the major contributor for thermal conductivity enhancement. PMID:26353708

  19. Discovery of the interstellar chiral molecule propylene oxide (CH3CHCH2O)

    NASA Astrophysics Data System (ADS)

    McGuire, Brett A.; Carroll, P. Brandon; Loomis, Ryan A.; Finneran, Ian A.; Jewell, Philip R.; Remijan, Anthony J.; Blake, Geoffrey A.

    2016-06-01

    Life on Earth relies on chiral molecules—that is, species not superimposable on their mirror images. This manifests itself in the selection of a single molecular handedness, or homochirality, across the biosphere. We present the astronomical detection of a chiral molecule, propylene oxide (CH3CHCH2O), in absorption toward the Galactic center. Propylene oxide is detected in the gas phase in a cold, extended molecular shell around the embedded, massive protostellar clusters in the Sagittarius B2 star-forming region. This material is representative of the earliest stage of solar system evolution in which a chiral molecule has been found.

  20. Safe antifreeze: The real difference between ethylene glycol and propylene glycol

    SciTech Connect

    Wray, T.K.

    1995-04-01

    Antifreeze-coolants are added to the radiators of internal combustion engines to prevent freezing during the winter and boil-over during the summer. Although ethylene glycol is the most commonly used coolant, products containing propylene glycol have been used--at least, experimentally--for years. Both substances have similar characteristics; however, some manufacturers claim that antifreeze-coolants containing propylene glycol are more environmentally friendly and safer to humans and animals than ethylene glycol products. This article examines these two substances, and addresses the similarities and differences of their physical and chemical compounds, thereby enabling users to determine whether such claims are valid or merely advertising hyperbole.

  1. Discovery of the interstellar chiral molecule propylene oxide (CH₃CHCH₂O).

    PubMed

    McGuire, Brett A; Carroll, P Brandon; Loomis, Ryan A; Finneran, Ian A; Jewell, Philip R; Remijan, Anthony J; Blake, Geoffrey A

    2016-06-17

    Life on Earth relies on chiral molecules-that is, species not superimposable on their mirror images. This manifests itself in the selection of a single molecular handedness, or homochirality, across the biosphere. We present the astronomical detection of a chiral molecule, propylene oxide (CH3CHCH2O), in absorption toward the Galactic center. Propylene oxide is detected in the gas phase in a cold, extended molecular shell around the embedded, massive protostellar clusters in the Sagittarius B2 star-forming region. This material is representative of the earliest stage of solar system evolution in which a chiral molecule has been found. PMID:27303055

  2. Synthesis and characterization of microporous inorganic membranes for propylene/propane separation

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoli

    Membrane-based gas separation is promising for efficient propylene/propane (C3H6/C3H8) separation with low energy consumption and minimum environment impact. Two microporous inorganic membrane candidates, MFI-type zeolite membrane and carbon molecular sieve membrane (CMS) have demonstrated excellent thermal and chemical stability. Application of these membranes into C3H6/C3H 8 separation has not been well investigated. This dissertation presents fundamental studies on membrane synthesis, characterization and C3H 6/C3H8 separation properties of MFI zeolite membrane and CMS membrane. MFI zeolite membranes were synthesized on α-alumina supports by secondary growth method. Novel positron annihilation spectroscopy (PAS) techniques were used to non-destructively characterize the pore structure of these membranes. PAS reveals a bimodal pore structure consisting of intracrystalline zeolitic micropores of ~0.6 nm in diameter and irregular intercrystalline micropores of 1.4 to 1.8 nm in size for the membranes. The template-free synthesized membrane exhibited a high permeance but a low selectivity in C3H 6/C3H8 mixture separation. CMS membranes were synthesized by coating/pyrolysis method on mesoporous gamma-alumina support. Such supports allow coating of thin, high-quality polymer films and subsequent CMS membranes with no infiltration into support pores. The CMS membranes show strong molecular sieving effect, offering a high C3H 6/C3H8 mixture selectivity of ~30. Reduction in membrane thickness from 500 nm to 300 nm causes an increase in C3H8 permeance and He/N2 selectivity, but a decrease in the permeance of He, N 2 and C3H6 and C3H6/C 3H8 selectivity. This can be explained by the thickness dependent chain mobility of the polymer film resulting in final carbon membrane of reduced pore size with different effects on transport of gas of different sizes, including possible closure of C3H6-accessible micropores. CMS membranes demonstrate excellent C3H6/C 3H8 separation

  3. Solvent effects on modulus of poly(propylene oxide)-based organogels as measured by cavitation rheology.

    PubMed

    Bentz, Kyle C; Walley, Susan E; Savin, Daniel A

    2016-06-14

    A series of novel organogels were synthesized from poly(propylene oxide) (PPO) functionalized with main chain urea moieties which provided rapid gelation and high moduli in a variety of solvents. Three different molecular weight PPOs were used in this study: 430, 2000, and 4000 g mol(-1), each with α,ω-amino-end groups. Four urea groups were introduced into the main chain by reaction with hexamethylene diisocyanate followed by subsequent reaction with a monofunctional alkyl or aromatic amine. This PPO/urea gelator was found to form gels in carbon tetrachloride, chloroform, dichloromethane, toluene, ethyl acetate, and tetrahydrofuran. Among these, carbon tetrachloride and toluene were found to be the best solvents for this system, resulting in perfectly clear gels with high moduli at low mass fraction for PPO-2000 systems. Flory-Huggins polymer-solvent interaction parameter, χ, was found to be a useful indicator of gel quality for these systems, with χCCl4/PPO-2000 < 0.5 and χtoluene/PPO-2000≈ 0.5. Systems with χ parameters >0.5 were found to form low moduli gels, indicating that for these systems, polymer-solvent interaction parameters can be a useful predictor of gel quality in different solvent systems. PMID:27181162

  4. Co-production of bio-oil and propylene through the hydrothermal liquefaction of polyhydroxybutyrate producing cyanobacteria.

    PubMed

    Wagner, Jonathan; Bransgrove, Rachel; Beacham, Tracey A; Allen, Michael J; Meixner, Katharina; Drosg, Bernhard; Ting, Valeska P; Chuck, Christopher J

    2016-05-01

    A polyhydroxybutyrate (PHB) producing cyanobacteria was converted through hydrothermal liquefaction (HTL) into propylene and a bio-oil suitable for advanced biofuel production. HTL of model compounds demonstrated that in contrast to proteins and carbohydrates, no synergistic effects were detected when converting PHB in the presence of algae. Subsequently, Synechocystis cf. salina, which had accumulated 7.5wt% PHB was converted via HTL (15% dry weight loading, 340°C). The reaction gave an overall propylene yield of 2.6%, higher than that obtained from the model compounds, in addition to a bio-oil with a low nitrogen content of 4.6%. No propylene was recovered from the alternative non-PHB producing cyanobacterial strains screened, suggesting that PHB is the source of propylene. PHB producing microorganisms could therefore be used as a feedstock for a biorefinery to produce polypropylene and advanced biofuels, with the level of propylene being proportional to the accumulated amount of PHB. PMID:26881334

  5. Size-dependent selectivity and activity of silver nanoclusters in the partial oxidation of propylene to propylene oxide and acrolein : A joint experimental and theoretical study.

    SciTech Connect

    Molina, L M.; Lee, S.; Sell, K.; Barcaro, G.; Fortunelli, A.; Lee, B.; Seifert, S.; Winans, R. E.; Elam, J. W.; Pellin, M. J.; Barke, I.; von Oeynhausen, V.; Lei, Y.; Meyer, R. J.; Alonso, J. A.; Fraile-Rodriguez, A.; Kleibert, A.; Giorgio, S.; Henry, C. R.; Heinz Meiwes-Broer, K.; Vadja, S.; Univ. de Valladolid; Univ. Rostock; IPCF-CNR; Univ. of Illinois at Chicago; Swiss Light Source; CINaM-CNRS and Aix-Marseille Univ.; Yale Univ.

    2011-02-02

    Model silver nanocatalysts between 9 and 23 nm in size were prepared by size-selected cluster deposition from a free cluster beam on amorphous alumina films and their size-dependent catalytic performance studied in the partial oxidation of propylene under realistic reaction conditions. Smaller clusters preferentially produced acrolein, while the 23 nm particles were considerably more selective towards the formation of propylene oxide, at reaction rates far exceeding those previously reported for larger silver particles. The activity of clusters dropped significantly with increasing particle size. First-principle calculations, of the activation energies for oxygen adsorption and its dissociation, at variable surface coverage yielded surface energies which resulted in particle shapes resembling the experimentally observed shapes of partially oxidized silver clusters. The calculated activation barriers for propylene oxide and acrolein formation on various facets and on the edges of the nanoparticles provided detailed information about the energetics of the competing reaction pathways. The size- and corresponding morphology dependent theoretical activity and selectivity are in good accord with experimental observations.

  6. Decay dynamics of nascent acetonitrile and nitromethane dipole-bound anions produced by intracluster charge-transfer

    SciTech Connect

    Yandell, Margaret A.; King, Sarah B.; Neumark, Daniel M.

    2014-05-14

    Decay dynamics of nascent dipole bound states of acetonitrile and nitromethane are examined using time-resolved photoelectron imaging of iodide-acetonitrile (I{sup −}·CH{sub 3}CN) and iodide-nitromethane (I{sup −}·CH{sub 3}NO{sub 2}) complexes. Dipole-bound anions are created by UV-initiated electron transfer to the molecule of interest from the associated iodide ion at energies just below the vertical detachment energy of the halide-molecule complex. The acetonitrile anion is observed to decay biexponentially with time constants in the range of 4–900 ps. In contrast, the dipole bound state of nitromethane decays rapidly over 400 fs to form the valence bound anion. The nitromethane valence anion species then decays biexponentially with time constants of 2 ps and 1200 ps. The biexponential decay dynamics in acetonitrile are interpreted as iodine atom loss and autodetachment from the excited dipole-bound anion, followed by slower autodetachment of the relaxed metastable ion, while the dynamics of the nitromethane system suggest that a dipole-bound anion to valence anion transition proceeds via intramolecular vibrational energy redistribution to nitro group modes in the vicinity of the iodine atom.

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

    SciTech Connect

    Kasai, Yukako; Yoshida, Norio Nakano, Haruyuki

    2015-05-28

    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{sup −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{sup −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.

  8. Effect of the physicochemical parameters of benzimidazole molecules on their retention by a nonpolar sorbent from an aqueous acetonitrile solution

    NASA Astrophysics Data System (ADS)

    Shafigulin, R. V.; Safonova, I. A.; Bulanova, A. V.

    2015-09-01

    The effect of the structure of benzimidazoles on their chromatographic retention on octadecyl silica gel from an aqueous acetonitrile eluent was studied. One- and many-parameter correlation equations were obtained by linear regression analysis, and their prognostic potential in determining the retention factors of benzimidazoles under study was analyzed.

  9. 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.

  10. A novel liquid/liquid extraction process composed of surfactant and acetonitrile for purification of polygalacturonase enzyme from Durio zibethinus.

    PubMed

    Amid, Mehrnoush; Manap, Yazid; Azmira, Farhana; Hussin, Muhaini; Sarker, Zaidul Islam

    2015-07-01

    Polygalacturonase is one of the important enzymes used in various industries such as food, detergent, pharmaceutical, textile, pulp and paper. A novel liquid/liquid extraction process composed of surfactant and acetonitrile was employed for the first time to purify polygalacturonase from Durio zibethinus. The influences of different parameters such as type and concentration of surfactants, concentrations of acetonitrile and composition of surfactant/acetonitrile on partitioning behavior and recovery of polygalacturonase was investigated. Moreover, the effect of pH of system and crude load on purification fold and yield of purified polygalacturonase were studied. The results of the experiment indicated the polygalacturonase was partitioned into surfactant top rich phase with impurities being partitioned into acetonitrile bottom rich phase in the novel method of liquid/liquid process composed of 23% (w/w) Triton X-100 and 19% (w/w) acetonitrile, at 55.6% of TLL (tie line length) crude load of 25% (w/w) at pH 6.0. Recovery and recycling of components also was measured in each successive step of liquid/liquid extraction process. The enzyme was successfully recovered by the method with a high purification factor of 14.3 and yield of 97.3% while phase components were also recovered and recycled above 95%. This study demonstrated that the novel method of liquid/liquid extraction process can be used as an efficient and economical extraction method rather than the traditional methods of extraction for the purification and recovery of the valuable enzyme. PMID:25973865

  11. Quantitative determination of aflatoxin B1 concentration in acetonitrile by chemometric methods using terahertz spectroscopy.

    PubMed

    Ge, Hongyi; Jiang, Yuying; Lian, Feiyu; Zhang, Yuan; Xia, Shanhong

    2016-10-15

    Aflatoxins contaminate and colonize agricultural products, such as grain, and thereby potentially cause human liver carcinoma. Detection via conventional methods has proven to be time-consuming and complex. In this paper, the terahertz (THz) spectra of aflatoxin B1 in acetonitrile solutions with concentration ranges of 1-50μg/ml and 1-50μg/l are obtained and analyzed for the frequency range of 0.4-1.6THz. Linear and nonlinear regression models are constructed to relate the absorption spectra and the concentrations of 160 samples using the partial least squares (PLS), principal component regression (PCR), support vector machine (SVM), and PCA-SVM methods. Our results indicate that PLS and PCR models are more accurate for the concentration range of 1-50μg/ml, whereas SVM and PCA-SVM are more accurate for the concentration range of 1-50μg/l. Furthermore, ten unknown concentration samples extracted from mildewed maize are analyzed quantitatively using these methods. PMID:27173565

  12. DFT simulation, quantum chemical electronic structure, spectroscopic and structure-activity investigations of 2-benzothiazole acetonitrile.

    PubMed

    Arjunan, V; Thillai Govindaraja, S; Jose, Sujin P; Mohan, S

    2014-07-15

    The Fourier transform infrared and FT-Raman spectra of 2-benzothiazole acetonitrile (BTAN) have been recorded in the range 4000-450 and 4000-100 cm(-1) respectively. The conformational analysis of the compound has been carried out to obtain the stable geometry of the compound. The complete vibrational assignment and analysis of the fundamental modes of the compound are carried out using the experimental FTIR and FT-Raman data and quantum chemical studies. The experimental vibrational frequencies are compared with the wavenumbers derived theoretically by B3LYP gradient calculations employing the standard 6-31G(**), high level 6-311++G(**) and cc-pVTZ basis sets. The structural parameters, thermodynamic properties and vibrational frequencies of the normal modes obtained from the B3LYP methods are in good agreement with the experimental data. The (1)H (400 MHz; CDCl3) and (13)C (100 MHz;CDCl3) nuclear magnetic resonance (NMR) spectra are also recorded. The electronic properties, the energies of the highest occupied and lowest unoccupied molecular orbitals are measured by DFT approach. The kinetic stability of the molecule has been determined from the frontier molecular orbital energy gap. The charges of the atoms and the structure-chemical reactivity relations of the compound are determined by its chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors by conceptual DFT methods. The non-linear optical properties of the compound have been discussed by measuring the polarisability and hyperpolarisability tensors. PMID:24662754

  13. Surprisingly Long-Lived Ascorbyl Radicals in Acetonitrile: Concerted Proton-Electron Transfer Reactions and Thermochemistry

    PubMed Central

    Warren, Jeffrey J.; Mayer, James M.

    2008-01-01

    Proton-coupled electron transfer (PCET) reactions and thermochemistry of 5,6-isopropylidene ascorbate (iAscH−) have been examined in acetonitrile solvent.iAscH− is oxidized by 2,4,6-tBu3C6H2O• and by excess TEMPO• to give the corresponding 5,6-isopropylidene ascorbyl radical anion (iAsc•−), which persists for hours at 298 K in dry MeCN solution. The stability of iAsc•− is surprising in light of the transience of the ascorbyl radical in aqueous solutions, and is due to the lack of the protons needed for radical disproportionation. A concerted proton-electron transfer (CPET) mechanism is indicated for the reactions of iAscH−. Redox potential, pKa and equilibrium measurements define the thermochemical landscape for 5,6-isopropylidene ascorbic acid and its derivatives in MeCN. These measurements give an O–H bond dissociation free energy (BDFE) for iAscH−of 65.4 ± 1.5 kcal mol−1 in MeCN. Similar studies on underivatized ascorbate indicate a BDFE of 67.8 ± 1.2 kcal mol−1. These values are much lower than the aqueous BDFE for ascorbate of 74.0 ± 1.5 kcal mol−1 derived from reported data. PMID:18505256

  14. Surprisingly long-lived ascorbyl radicals in acetonitrile: concerted proton-electron transfer reactions and thermochemistry.

    PubMed

    Warren, Jeffrey J; Mayer, James M

    2008-06-18

    Proton-coupled electron transfer (PCET) reactions and thermochemistry of 5,6-isopropylidene ascorbate (iAscH-) have been examined in acetonitrile solvent. iAscH- is oxidized by 2,4,6-tBu3C6H2O. and by excess TEMPO. to give the corresponding 5,6-isopropylidene ascorbyl radical anion (iAsc.-), which persists for hours at 298 K in dry MeCN solution. The stability of iAsc.- is surprising in light of the transience of the ascorbyl radical in aqueous solutions and is due to the lack of the protons needed for radical disproportionation. A concerted proton-electron transfer (CPET) mechanism is indicated for the reactions of iAscH-. Redox potential, pKa and equilibrium measurements define the thermochemical landscape for 5,6-isopropylidene ascorbic acid and its derivatives in MeCN. These measurements give an O-H bond dissociation free energy (BDFE) for iAscH- of 65.4 +/- 1.5 kcal mol-1 in MeCN. Similar studies on underivatized ascorbate indicate a BDFE of 67.8 +/- 1.2 kcal mol-1. These values are much lower than the aqueous BDFE for ascorbate of 74.0 +/- 1.5 kcal mol-1 derived from reported data. PMID:18505256

  15. ALMA Spectroscopy of Titan's Atmosphere: First Detections of Vinyl Cyanide and Acetonitrile Isotopologues

    NASA Astrophysics Data System (ADS)

    Cordiner, Martin; Y Palmer, Maureen; Nixon, Conor A.; Charnley, Steven B.; Mumma, Michael J.; Irwin, Pat G. J.; Teanby, Nick A.; Kisiel, Zbigniew; Serigano, Joseph

    2015-11-01

    Studies of Titan's atmospheric chemistry provide a unique opportunity to explore the origin and evolution of complex organic matter in primitive planetary atmospheres. The Atacama Large Millimeter/submillimeter Array (ALMA) is a powerful new telescope, well suited to the study of molecular emission from Titan's stratosphere and mesosphere. Here we present early results from our ongoing study to exploit the large volume of Titan data taken using ALMA in Early Science Mode (during the period 2012-2014). Combining data from multiple ALMA Band 6 observations, we obtained high-resolution mm-wave spectra with unprecedented sensitivity, enabling the first detection of vinyl cyanide (C2H3CN) in Titan's atmosphere. Initial estimates indicate a mesospheric abundance ratio with respect to ethyl cyanide (C2H5CN) of [C2H3CN]/[C2H5CN] = 0.31. In addition, we report the first detections on Titan of the 13C and 15N-substituted isotopologues of acetonitrile (13CH3CN and CH3C15N). Radiative transfer models and possible chemical formation pathways for these molecules will be discussed.

  16. Impact of the propylene glycol-water-borax coolant on material recovery operations

    SciTech Connect

    Duerksen, W.K.; Taylor, P.A.

    1983-05-01

    The reaction of the propylene glycol-water-borax coolant with nitric acid has now been studied in some detail. This document is intended to provide a summary of the results. Findings are summarized under nine headings. Tests have also been conducted to determine if the new coolant would have any adverse effects on the uranium recycle systems. Experiments were scientifically designed after observation of the production operations so that accurate response to the immediate production concerns could be provided. Conclusions from these studies are: formation of glycol nitrates is very improbable; the reaction of concentrated (70%) nitric acid with pure propylene glycol is very violent and hazardous; dilution of the nitric acid-glycol mixture causes a drastic decrease in the rate and intensity of the reaction; the mechanism of the nitric acid propylene glycol reaction is autocatalytic in nitrous acid; no reaction is observed between coolant and 30% nitric acid unless the solution is heated; the coolant reacts fairly vigorously with 55% nitric acid after a concentration-dependent induction time; experiments showed that the dissolution of uranium chips that had been soaked in coolant proceeded at about the same rate as if the chips had not previously contacted glycol; thermodynamic calculations show that the enthalpy change (heat liberated) by the reaction of nitric acid (30%) with propylene glycol is smaller than if the same amount of nitric acid reacted with uranium. Each of these conclusions is briefly discussed. The effect of new coolant on uranium recycle operations is then briefly discussed.

  17. 21 CFR 172.765 - Succistearin (stearoyl propylene glycol hydrogen succinate).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Succistearin (stearoyl propylene glycol hydrogen succinate). 172.765 Section 172.765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN...

  18. 21 CFR 172.765 - Succistearin (stearoyl propylene glycol hydrogen succinate).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Succistearin (stearoyl propylene glycol hydrogen succinate). 172.765 Section 172.765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION...

  19. 21 CFR 172.765 - Succistearin (stearoyl propylene glycol hydrogen succinate).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Succistearin (stearoyl propylene glycol hydrogen succinate). 172.765 Section 172.765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN...

  20. 21 CFR 172.765 - Succistearin (stearoyl propylene glycol hydrogen succinate).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Succistearin (stearoyl propylene glycol hydrogen succinate). 172.765 Section 172.765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN...

  1. TRAPPING FOR MEXICAN FRUIT FLY (DIPTERA: TEPHRITIDAE) WITH TORULA YEAST AND PROPYLENE GLYCOL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In south Texas, propylene glycol is added to the liquid bait (an aqueous slurry of torula yeast) in surveillance traps for exotic fruit flies to better preserve captured specimens. In a series of tests in Texas and Mexico, overall captures of Mexican fruit flies were roughly the same in traps with ...

  2. Differences in Catalytic Sites for CO Oxidation and Propylene Epoxidation on Au Nanoparticles

    SciTech Connect

    Lee, W.S.; Stach, E.; Zhang, R.; Akatay, M.C.; Baertsch, C.D.; Ribeiro, F.H.; Delgass, W.N.

    2011-08-29

    Sintering and increased Au loading of Au/TS-1 causes the rate of CO oxidation per mole of Au to increase, whereas that for epoxidation of propylene in O{sub 2} and H{sub 2} decreases. This opposite trend in rate behavior shows that the catalytic sites for the two reactions must be different.

  3. PRODUCTION OF ORGANIC NITRATES FROM HYDROXYL AND NITRATE RADICAL REACTION WITH PROPYLENE

    EPA Science Inventory

    Measurements of the gas-phase production rates of alpha-nitratoacetone, propylene glycol dinitrate, 2-hydroxy propyl nitrate, and 2-nitrato propyl alcohol (2-NPA) in a C3H6/N2O5/air dark reaction and a C3H6/NOX/air irradiation are reported. The probable operative reaction mechani...

  4. Quantifying residues from postharvest fumigation of almonds and walnuts with propylene oxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel analytical approach, involving solvent extraction with methyl tert-butyl ether (MTBE) followed by gas chromatography (GC), was developed to quantify residues that result from the postharvest fumigation of almonds and walnuts with propylene oxide (PPO). Verification and quantification of PPO,...

  5. Synthesis and characterization of DI-[3-(trimethylsilyl)-1-propylene] alkylenediphosphonic acids.

    SciTech Connect

    Griffith-Dzielawa, J. A.; Barrans, R. E., Jr.; McAlister, D. R.; Dietz, M. L.; Herlinger, A. W.; Chemistry; Loyola Univ. of Chicago

    2000-01-01

    A homologous series of alkylenediphosphonic acids was successfully esterified with 3-(trimethylsilyl)-1-propanol to the symmetrically-substituted diesters. The procedure, which has general applicability for incorporating silicon heteroatoms into diphosphonic acids, utilizes the esterification reagent dicyclohexyl-carbodiimide (DCC) to activate the acid. The aggregation properties of the di-[3-(trimethylsilyl)-1-propylene] alkylenediphosphonic acids were measured in toluene and 1-decanol.

  6. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) The additive meets the following specifications: Water insoluble combined lactic acid, 14-18 percent... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Lactylated fatty acid esters of glycerol and... CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene...

  7. Conversion of 1,3-Propylene Glycol on Rutile TiO2(110)

    SciTech Connect

    Chen, Long; Li, Zhenjun; Smith, R. Scott; Kay, Bruce D.; Dohnalek, Zdenek

    2014-10-09

    The adsorption of 1,3-propylene glycol (1,3-PG) on partially reduced TiO2(110) and its conversion to products have been studied by a combination of molecular beam dosing and temperature programmed desorption (TPD). When the Ti surface sites are saturated by 1,3-PG, ~80% of the molecules undergo further reactions to yield products that are liberated during the TPD ramp. In contrast to ethylene glycol (EG) and 1,2- propylene glycol (1,2-PG) that yield only alkenes and water at very low coverages (< 0.05 ML), two additional products, HCHO and C2H4, along with propylene (CH3CHCH2) and water are observed for 1,3-PG. Identical TPD line shapes and desorption yields for HCHO and C2H4 suggest that these products result from C-C bond cleavage and are coupled. At higher 1,3-PG coverages (> 0.1 ML), propanal (CH3CH2CHO) and two additional products, 1-propanol (CH3CH2CH2OH) and acrolein (CH2CHCHO), are observed. The desorption of 1-propanol is found to be coupled with the desorption of acrolein, suggesting that these products are formed by the disproportionation of two 1,3-PG molecules. The coverage dependent TPD results further show that propylene formation dominates at low coverages (< 0.3 ML), while the decomposition and disproportionation channels increase rapidly at higher coverages and reach yields comparable to that of propylene at the 1,3-PG saturation coverage of 0.5 ML. The observed surface chemistry clearly shows how the molecular structure of glycols influences their reaction pathways on oxide surfaces.

  8. Role of Cl - ions in photooxidation of propylene on TiO 2 surface

    NASA Astrophysics Data System (ADS)

    Guo, Jianhui; Mao, Liqun; Zhang, Jiwei; Feng, Caixia

    2010-01-01

    The effect of Cl - ions on photooxidation of propylene on TiO 2 semiconductor was investigated. Cl -/TiO 2 catalysts were prepared by annealing Degussa P25 TiO 2 in the gas flow of N 2 and Cl 2 under 100-400 °C. The photocatalytic oxidation of propylene was carried out in a continuous flow system, with the chromatograph to analyze the products on line. The experimental results showed that the activity of Cl -/TiO 2 catalysts increased as heat-treated temperature decreased. The activity of the sample heat-treated at 100 °C was about two times higher than that of pure TiO 2. Moreover, as to TiO 2, the main product of the propylene photocatalytic oxidation was CO 2, but with Cl -/TiO 2 catalysts, not only CO 2 but also trace CO was determined. The adsorbed species on TiO 2 surface before and after reaction were analyzed by X-ray photoelectron spectroscopy (XPS) and thermogravimetric/differential thermal analyses (TG-DTA) coupled to a mass spectrometer (MS). XPS analysis showed that there was Cl - absorbed on the Cl -/TiO 2 surface, and the absorption amount of Cl - decreased after the photooxidation reaction of propylene. TG-DTA-MS analysis confirmed chlorine absorbed on the surface of TiO 2 in the form of Cl - ion. These results illuminated that absorbed Cl - on the surface of TiO 2 formed a weak physical absorption on TiO 2 at low temperature, and subsequently participated in the photooxidation of propylene, finally removed from TiO 2 surface.

  9. Inhibition of heavy metal ion corrosion on aluminum in fresh water cooling systems using propylene glycol anti-freeze

    SciTech Connect

    Hack, H.P.; Corbett, R.; Krantz, B.

    1998-12-31

    Electronics cooling and environmental control systems are required in enclosed manned spaces such as the inside of spacecraft or submersibles. Because egress from such spaces may not be possible in a short time frame, coolant leaks must have minimum toxicity. For this reason, propylene glycol coolants are preferred over the traditional ethylene glycol coolants. Corrosion inhibitor formulations are well developed for ethylene glycol coolants, but there is concern that the inhibitor suite for propylene glycol systems may not be as mature. In particular, coolant systems with a mixture of aluminum and copper can develop heavy metal ion corrosion of the aluminum due to precipitation of copper ions from solution onto the aluminum. This type of accelerated corrosion of aluminum does not require electrical contact with copper, as is the case for galvanic corrosion, nor is significant coolant conductivity required for corrosion to occur. This paper presents a study of the ability of a commercial inhibited propylene glycol coolant to prevent heavy metal ion corrosion of aluminum when copper is also present in the coolant system. The inhibited propylene glycol`s performance is compared to that of reagent propylene glycol without inhibitors, a mature ethylene glycol inhibited coolant, and to tap water. The inhibitor suite in the inhibited propylene glycol was found to be as effective in controlling heavy metal ion corrosion as that of the inhibited ethylene glycol coolant, while uninhibited reagent propylene glycol was ineffective in controlling heavy metal ion corrosion.

  10. Microbial Degradation of Propylene Glycol - Modelling Approach of a Batch Experiment

    NASA Astrophysics Data System (ADS)

    Dathe, Annette; Fernandez, Perrine; Bakken, Lars; Bloem, Esther; French, Helen

    2016-04-01

    De-icing chemicals are applied in large amounts at airports during winter conditions to keep the runways and aircrafts ice-free. At Gardermoen airport, Norway, most of the applied chemicals can be captured, but about 10 to 20 % infiltrate into the soil along the runways and during take-off. While the commonly used propylene glycol (PG) is easily degradable by local microbial communities, its biological oxygen demand is high, anoxic zones can develop and soluble Fe+2 and Mn+2 ions eventually can reach the groundwater. The objectives of the presented study are to quantify the mechanisms, which control the order of reduction processes in an unsaturated sandy soil, and to test whether measured redox potentials can help to determine underlying biogeochemical reactions. To investigate the mechanisms of microbial degradation, the water phase of soil samples from Gardermoen Airport was replaced by deionized water with 10 mMol PG or 10 mMol glutamate and the samples were incubated at 10°C for about two weeks. The gas phase was sampled and analyzed automatically every three hours. Microbial degradation of the substrate (PG or glutamate) was modelled following a Monod kinetics using the FME (Flexible Modelling Environment) package of R (Project for Statistical Computing). The model was calibrated against measurements of O2 depletion and CO2 production. The initial concentrations of O2, CO2 and PG or glutamate are known and microbial yields and stoichiometric constants can be calculated from the measurements. Parameter values for the initial microbial population size, maximum microbial growth rate, the half saturation constant, and microbial degradation and respiration rates were fitted using the FME package. The model accounts for carbon from the substrate (PG or glutamate) incorporated into the biomass. Results are promising, but because of the large number of parameters needed to fit a Monod kinetics it is challenging to accurately model a whole redox sequence. The

  11. The solvation of ions in acetonitrile and acetone. II. Monte Carlo simulations using polarizable solvent models

    NASA Astrophysics Data System (ADS)

    Fischer, R.; Richardi, J.; Fries, P. H.; Krienke, H.

    2002-11-01

    Structural properties and energies of solvation are simulated for alkali and halide ions. The solvation structure is discussed in terms of various site-site distribution functions, of solvation numbers, and of orientational correlation functions of the solvent molecules around the ions. The solvent polarizability has notable effects which cannot be intuitively predicted. In particular, it is necessary to reproduce the experimental solvation numbers of small ions. The changes of solvation properties are investigated along the alkali and halide series. By comparing the solvation of ions in acetone to that in acetonitrile, it is shown that the spatial correlations among the solvent molecules around an ion result in a strong screening of the ion-solvent direct intermolecular potential and are essential to understand the changes in the solvation structures and energies between different solvents. The solvation properties derived from the simulations are compared to earlier predictions of the hypernetted chain (HNC) approximation of the molecular Ornstein-Zernike (MOZ) theory [J. Richardi, P. H. Fries, and H. Krienke, J. Chem. Phys. 108, 4079 (1998)]. The MOZ(HNC) formalism gives an overall qualitatively correct picture of the solvation and its various unexpected findings are corroborated. For the larger ions, its predictions become quantitative. The MOZ approach allows to calculate solvent-solvent and ion-solvent potentials of mean force, which shed light on the 3D labile molecular and ionic architectures in the solution. These potentials of mean force convey a unique information which is necessary to fully interpret the angle-averaged structural functions computed from the simulations. Finally, simulations of solutions at finite concentrations show that the solvent-solvent and ion-solvent spatial correlations at infinite dilution are marginally altered by the introduction of fair amounts of ions.

  12. Iron(II) catalysis in oxidation of hydrocarbons with ozone in acetonitrile

    DOE PAGESBeta

    Bataineh, Hajem; Pestovsky, Oleg; Bakac, Andreja

    2015-02-11

    Oxidation of alcohols, ethers, and sulfoxides by ozone in acetonitrile is catalyzed by submillimolar concentrations of Fe(CH3CN)62+. The catalyst provides both rate acceleration and greater selectivity toward the less oxidized products. For example, Fe(CH3CN)62+-catalyzed oxidation of benzyl alcohol yields benzaldehyde almost exclusively (>95%), whereas the uncatalyzed reaction generates a 1:1 mixture of benzaldehyde and benzoic acid. Similarly, aliphatic alcohols are oxidized to aldehydes/ketones, cyclobutanol to cyclobutanone, and diethyl ether to a 1:1 mixture of ethanol and acetaldehyde. The kinetics of oxidation of alcohols and diethyl ether are first-order in [Fe(CH3CN)62+] and [O3] and independent of [substrate] at concentrations greater thanmore » ~5 mM. In this regime, the rate constant for all of the alcohols is approximately the same, kcat = (8 ± 1) × 104 M–1 s–1, and that for (C2H5)2O is (5 ± 0.5) × 104 M–1 s–1. In the absence of substrate, Fe(CH3CN)62+ reacts with O3 with kFe = (9.3 ± 0.3) × 104 M–1 s–1. The similarity between the rate constants kFe and kcat strongly argues for Fe(CH3CN)62+/O3 reaction as rate-determining in catalytic oxidation. The active oxidant produced in Fe(CH3CN)62+/O3 reaction is suggested to be an Fe(IV) species in analogy with a related intermediate in aqueous solutions. As a result, this assignment is supported by the similarity in kinetic isotope effects and relative reactivities of the two species toward substrates.« less

  13. Liquid-layering induced, temperature-dependent thermal conductivity enhancement in ZnO-propylene glycol nanofluids

    NASA Astrophysics Data System (ADS)

    Suganthi, Kuppusamy Swaminathan; Parthasarathy, Meera; Rajan, Kalpoondi Sekar

    2013-03-01

    Experiments were carried out on preparation of colloidal dispersions of ZnO nanoparticles in propylene glycol leading to ZnO-propylene glycol nanofluids. Thermal conductivity of these nanofluids was measured as a function of nanoparticle concentration (⩽2 vol.%), temperature (10-60 °C) and aggregate size. A strong dependence of thermal conductivity enhancement on temperature with higher enhancements at lower temperatures has been observed. Our results on temperature and aggregation dependence of thermal conductivity enhancement show that the thermal conductivity enhancement in ZnO-propylene glycol nanofluids is attributed to formation of solvation layers (liquid layers) of base fluid on the ZnO nanoparticle surfaces.

  14. Kinetics and mechanism of monomolecular heterolysis of framework compounds. VI. Dehydrobromination of 2-bromo-2-methyladamantane in acetonitrile

    SciTech Connect

    Ponomareva, E.A.; Vasil'kevich, A.I.; Tarsenko, P.V.; Dvorko, G.F.

    1988-08-10

    The kinetics of dehydrobromination of 2-bromo-2-methyladamantane in acetonitrile were studied in the presence of triphenylverdazyl as internal indicator; k/sub 25/ = 8.57 /times/ 10/sup /minus/5/ sec/sup /minus/1/, /Delta/H/sup /ne// 79 kJ/mole, /Delta/S/sup /ne// /minus/58 kJ/mole /times/ deg. Additions of water, phenols, lithium perchlorate, and bromides increase the reaction rate, and additions of nitrates and picrates reduce it. A similar pattern is observed in the dehydrobromination of tert-butyl bromide in acetonitrile. In the presence of tetraethylammonium chloride the heterolysis rate of 2-bromo-2-methyladamantane decreases, while that of tert-butyl bromide increases. The positive salt effect is explained by stabilization of the transition state by the salt, and the negative salt effect is explained by the reaction of the anion with the sterically separated or solvent-separated ion pair of the substrate.

  15. Fluorescence of excited charge-transfer complexes and absolute dynamics of radical-ion pairs in acetonitrile

    SciTech Connect

    Gould, I.R.; Farid, S.

    1992-09-17

    An analysis of the dynamics of the radical-ion pairs of a series of 2,6,9,10-tetracyanoanthracene acceptor/alkylbenzene donor systems in acetonitrile is described in this paper. This analysis is carried out by using a combination of time-resolved emission and absorption spectroscopies and measurements of {Phi} {sub ions} from the contact radical-ion pair (CRIP) and the solvent-separated radical-ion pair (SSRIP).

  16. Complexation dynamics of CH3SCN and Li(+) in acetonitrile studied by two-dimensional infrared spectroscopy.

    PubMed

    Kwon, YoungAh; Park, Sungnam

    2015-10-01

    Ion-molecule complexation dynamics were studied with CH3SCN and Li(+) in acetonitrile by vibrationally probing the nitrile stretching vibration of CH3SCN. The nitrile stretching vibration of CH3SCN has a long lifetime (T1 = ∼90 ps) and its frequency is significantly blue-shifted when CH3SCN is bound with Li(+) ions to form a CH3SCNLi(+) complex in acetonitrile. Such spectral properties enable us to distinguish free CH3SCN and the CH3SCNLi(+) complex in solutions and measure their dynamics occurring on hundred picosecond timescales. For the complexation between CH3SCN and Li(+) in acetonitrile, the change in enthalpy (ΔH = -7.17 kJ mol(-1)) and the change in entropy (ΔS = -34.4 J K(-1) mol(-1)) were determined by temperature-dependent FTIR experiments. Polarization-controlled infrared pump-probe (IR PP) spectroscopy was used to measure the population decay and orientational dynamics of free CH3SCN and the CH3SCNLi(+) complex. Especially, the orientational relaxation of the CH3SCNLi(+) complex was found to be almost 3 times slower than those of free CH3SCN because Li(+) ions strongly interact with the neighboring solvents. Most importantly, the complexation dynamics of CH3SCN and Li(+) in acetonitrile were successfully measured in real time by 2DIR spectroscopy for the first time and the dissociation and association time constants were directly determined by using the two-species exchange kinetic model. Our experimental results provide a comprehensive overview of the ion-molecule complexation dynamics in solutions occurring under thermal equilibrium conditions. PMID:26323322

  17. Effects of oxytetracycline in propylene glycol, oxytetracycline in saline solution, and propylene glycol alone on blood ionized calcium and plasma total calcium in sheep.

    PubMed

    Button, C; Mülders, M S

    1984-08-01

    Intravenous injection of oxytetracycline HC1 (OTC) in propylene glycol (PG), OTC in saline solution, and PG alone in sheep had no significant (P less than 0.01) effects on total plasma calcium concentrations over a 60-minute period. In contrast, ionized calcium concentrations in whole blood were significantly (P less than 0.01) depressed for approximately 3 minutes after OTC in PG and OTC in saline solution, IV. A slight depression of ionized calcium concentrations was noticed after injection of PG alone. Seemingly, calcium chelation by OTC may be a major factor in the collapse syndrome of ungulates given preparations containing OTC by rapid IV injection. PMID:6476580

  18. Bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400, and polyethylene glycol 1000 against selected microorganisms

    PubMed Central

    Nalawade, Triveni Mohan; Bhat, Kishore; Sogi, Suma H. P.

    2015-01-01

    Aim: The aim of the present study was to evaluate the bactericidal activity of propylene glycol, glycerine, polyethylene glycol 400 (PEG 400), and polyethylene glycol 1000 (PEG 1000) against selected microorganisms in vitro. Materials and Methods: Five vehicles, namely propylene glycol, glycerine, PEG 400, PEG 1000, and combination of propylene glycol with PEG 400, were tested for their bactericidal activity. The minimum bactericidal concentration was noted against four standard strains of organisms, i.e. Streptococcus mutans American Type Culture Collection (ATCC) 25175, Streptococcus mutans ATCC 12598, Enterococcus faecalis ATCC 35550, and Escherichia coli ATCC 25922, using broth dilution assay. Successful endodontic therapy depends upon thorough disinfection of root canals. In some refractory cases, routine endodontic therapy is not sufficient, so intracanal medicaments are used for proper disinfection of canals. Intracanal medicaments are dispensed with vehicles which aid in increased diffusion through the dentinal tubules and improve their efficacy. Among the various vehicles used, glycerine is easily available, whereas others like propylene glycol and polyethylene glycol have to be procured from appropriate sources. Also, these vehicles, being viscous, aid in sustained release of the medicaments and improve their handling properties. The most commonly used intracanal medicaments like calcium hydroxide are ineffective on many microorganisms, while most of the other medicaments like MTAD (Mixture of Tetracycline, an Acid, and a Detergent) and Triple Antibiotic Paste (TAP) consist of antibiotics which can lead to development of antibiotic resistance among microorganisms. Thus, in order to use safer and equally effective intracanal medicaments, newer alternatives like chlorhexidine gluconate, ozonized water, etc., are being explored. Similarly, the five vehicles mentioned above are being tested for their antimicrobial activity in this study. Results: All vehicles

  19. Photochemical oxidation of thiophene by O2 in an oil/acetonitrile two-phase extraction system.

    PubMed

    Li, Fa-Tang; Zhao, Di-Shun; Li, Hong-Xia; Liu, Rui-Hong

    2008-10-01

    Photochemical oxidation of thiophene in an n-octane/acetonitrile extraction system using O(2) as oxidant was studied. Results obtained here can be used as a reference for desulfurization of gasoline, because thiophene is one of the main components containing sulfur in fluid catalytic cracking gasoline. A 500-W high-pressure mercury lamp was used as a light source for irradiation, and air was introduced by a gas pump to supply O(2). Thiophene dissolved in nopolar n-octane solvent was photodecomposed and removed into the polar acetonitrile phase. The desulfurization rate of thiophene in n-octane was 65.2% under photoirradiation for 5 h under the conditions of air flow at 150 mL min(-1), and V(n-octane):V(acetonitrile) = 1:1. This can be improved to 96.5% by adding 0.15 g Na-ZSM-5 zeolite into the 100-mL reaction system, which is the absorbent for O(2) and thiophene. Under such conditions, the photooxidation kinetics of thiophene with O(2) and Na-ZSM-5 zeolite is first-order with an apparent rate constant of 0.6297 h(-1) and half-time of 1.10 h. The sulfur content can be reduced from 800 microL L(-1) to 28 microL L(-1). PMID:18991938

  20. Iron(II) catalysis in oxidation of hydrocarbons with ozone in acetonitrile

    SciTech Connect

    Bataineh, Hajem; Pestovsky, Oleg; Bakac, Andreja

    2015-02-11

    Oxidation of alcohols, ethers, and sulfoxides by ozone in acetonitrile is catalyzed by submillimolar concentrations of Fe(CH3CN)62+. The catalyst provides both rate acceleration and greater selectivity toward the less oxidized products. For example, Fe(CH3CN)62+-catalyzed oxidation of benzyl alcohol yields benzaldehyde almost exclusively (>95%), whereas the uncatalyzed reaction generates a 1:1 mixture of benzaldehyde and benzoic acid. Similarly, aliphatic alcohols are oxidized to aldehydes/ketones, cyclobutanol to cyclobutanone, and diethyl ether to a 1:1 mixture of ethanol and acetaldehyde. The kinetics of oxidation of alcohols and diethyl ether are first-order in [Fe(CH3CN)62+] and [O3] and independent of [substrate] at concentrations greater than ~5 mM. In this regime, the rate constant for all of the alcohols is approximately the same, kcat = (8 ± 1) × 104 M–1 s–1, and that for (C2H5)2O is (5 ± 0.5) × 104 M–1 s–1. In the absence of substrate, Fe(CH3CN)62+ reacts with O3 with kFe = (9.3 ± 0.3) × 104 M–1 s–1. The similarity between the rate constants kFe and kcat strongly argues for Fe(CH3CN)62+/O3 reaction as rate-determining in catalytic oxidation. The active oxidant produced in Fe(CH3CN)62+/O3 reaction is suggested to be an Fe(IV) species in analogy with a related intermediate in aqueous solutions. As a result, this assignment is supported by the similarity in kinetic isotope effects and relative reactivities of the two species toward substrates.

  1. Structural and energetic properties of acetonitrile-Group IV (A & B) halide complexes.

    PubMed

    Helminiak, Heather M; Knauf, Robin R; Danforth, Samuel J; Phillips, James A

    2014-06-19

    We have conducted an extensive computational study of the structural and energetic properties of select acetonitrile-Group IV (A & B) tetrahalide complexes, both CH3CN-MX4 and (CH3CN)2-MX4 (M = Si, Ge, Ti; X = F, Cl). We have also examined the reactivity of CH3CN with SiF4, SiCl4, GeCl4, and TiCl4, and measured low-temperature IR spectra of thin films containing CH3CN with SiF4, GeCl4, or TiCl4. The six 1:1 complexes fall into two general structural classes. CH3CN-TiCl4, CH3CN-TiF4, and CH3CN-GeF4, exhibit relatively short M-N bonds (~2.3 Å), an intermediate degree of distortion in the MX4 subunit, and binding energies ranging from 11.0 to 13.0 kcal/mol. Conversely, CH3CN-GeCl4, CH3CN-SiF4, and CH3CN-SiCl4, are weakly bonded systems, with long M-N distances (>3.0 Å), little distortion in the MX4 subunit, and binding energies ranging from 3.0 to 4.4 kcal/mol. The structural features of analogous 2:1 systems resemble those of their 1:1 counterparts, whereas the binding energies (relative to three isolated fragments) are roughly twice as large. Calculated M-N potential curves in the gas phase and bulk, dielectric media are reported for all 1:1 complexes, and for two systems, CH3CN-GeF4 and CH3CN-SiF4, these data predict significant condensed-phase structural changes. The effect on the CH3CN-SiF4 potential is extreme; the curve becomes quite flat over a broad range in dielectric media, and at higher ε values, the global minimum shifts inward by about 1.0 Å. In bulk reactivity experiments, no reaction was observed between CH3CN and SiF4, SiCl4, or GeCl4, whereas CH3CN and TiCl4 were found to react immediately upon contact. Also, thin-film IR spectra indicate a strong interaction between CH3CN and TiCl4, yet only weak interactions between CH3CN and GeCl4 or SiF4 in the solid state. PMID:24852185

  2. A density functional theory study of propylene epoxidation on RuO2(110) surface

    NASA Astrophysics Data System (ADS)

    Atmaca, Deniz Onay; Düzenli, Derya; Ozbek, M. Olus; Onal, Isik

    2016-11-01

    Propylene epoxidation is investigated on RuO2(110) and oxygen added RuO2-Oot(110) surfaces by periodic DFT computational method. The desired product propylene oxide (PO) as well as the undesired products acetone (AC) or propionaldehyde (PA) form on both surfaces through either surface intermediate oxometallopropylene (OMMP) or direct oxygen insertion mechanisms. On RuO2(110) surface, nucleophilic lattice oxygen at bridge position (Obr) favors the stable surface intermediate mechanism where high energy requirements for forward reactions are demonstrated in our calculations. On RuO2-Oot(110) surface, however, higher reactivity of the electrophilic oxygen (Oot) species lowers the reaction barriers and enables an exothermic reaction path to the direct oxygen insertion for PO production. Therefore, RuO2-Oot surface is expected to show a higher PO rate.

  3. Mechanism of rhodium-catalyzed hydroacylation of propylene using formaldehyde: A computational study

    NASA Astrophysics Data System (ADS)

    Wang, Fen; Meng, Qingxi; Li, Ming

    Density functional theory was used to study Rh(I)-catalyzed hydroacylation of propylene and formaldehyde. All the intermediates and the transition states were optimized completely at the B3LYP/6-311++G(d,p) level (LANL2DZ(d) for Rh, P). Calculation results confirm that Rh(I)-catalyzed hydroacylation of propylene and formaldehyde is exothermic, and the total released Gibbs free energy is about -33 kJ mol-1. This hydroacylation have eight possible pathways, and pathways (1), (2), (3), and (4) are the dominant reaction channels. The dominant product predicted theoretically is butyl aldehyde, and it is a linear product, which agrees well with these experiments.

  4. Inhibited ethylene and propylene glycols for corrosion and freeze protection in water-based HVAC systems

    SciTech Connect

    Roo, A.M. de; Lee, B.W.

    1997-12-31

    Industrially inhibited ethylene and propylene glycols are used extensively to provide protection against equipment damage due to corrosion and freezing. This paper will describe the proper use of these glycols, including system preparation, fluid installation, and fluid maintenance. The impact of the use of these glycols on the operation of the system is discussed along with methods for overcoming any declines in heat transfer. From this discussion, it will become clear why automotive antifreeze formulations should not be used in heating, ventilating, and airconditioning (HVAC) systems. Also included are data on the physical properties of aqueous solutions of ethylene and propylene glycol, the concept of burst vs. freeze protection, typical results of corrosion tests, and methods to use to monitor the fluid for each application.

  5. Crystalline Isotactic Polar Polypropylene from the Palladium-Catalyzed Copolymerization of Propylene and Polar Monomers.

    PubMed

    Ota, Yusuke; Ito, Shingo; Kobayashi, Minoru; Kitade, Shinichi; Sakata, Kazuya; Tayano, Takao; Nozaki, Kyoko

    2016-06-20

    Moderately isospecific homopolymerization of propylene and the copolymerization of propylene and polar monomers have been achieved with palladium complexes bearing a phosphine-sulfonate ligand. Optimization of substituents on the phosphorus atom of the ligand revealed that the presence of bulky alkyl groups (e.g. menthyl) is crucial for the generation of high-molecular-weight polypropylenes (Mw ≈10(4) ), and the substituent at the ortho-position relative to the sulfonate group influences the molecular weight and isotactic regularity of the obtained polypropylenes. Statistical analysis suggested that the introduction of substituents at the ortho-position relative to the sulfonate group favors enantiomorphic site control over chain end control in the chain propagation step. The triad isotacticity could be increased to mm=0.55-0.59, with formation of crystalline polar polypropylenes, as supported by the presence of melting points and sharp peaks in the corresponding X-ray diffraction patterns. PMID:27161896

  6. Electronic effects in Ziegler-Natta polymerization of propylene and ethylene using soluble metallocene catalysts

    SciTech Connect

    Lee, Ik-Mo; Gauthier, W.J.; Ball, J.M.; Iyengar, B.; Collins, S.

    1992-06-01

    ({eta}{sup 5}-5,6-X{sub 2}C{sub 9}H{sub 5}){sub 2}ZrCl{sub 2} catalysts (4a, X = H; 4b, X = CH{sub 3}; 4d, X = OCH{sub 3}; 4e, X = Cl) were investigated as catalysts for the polymerization of ethylene. In addition, polymerization of propylene and ethylene was studied by using corresponding racemic, ethylene-bridged analogues (5a, X = H; 5b, X = CH{sub 3}; 5d, X = OCH{sub 3}). Both the bridged and non-bridged catalysts were effective as catalysts for both ethylene and propylene polymerization, but the molecular weights were generally lower with the ethylene-bridged catalyst. 19 refs., 3 tabs.

  7. Long Duration Life Test of Propylene Glycol Water Based Thermal Fluid Within Thermal Control Loop

    NASA Technical Reports Server (NTRS)

    Le, Hung; Hill, Charles; Stephan, Ryan A.

    2010-01-01

    Evaluations of thermal properties and resistance to microbial growth concluded that 50% Propylene Glycol (PG)-based fluid and 50% de-ionized water mixture was desirable for use as a fluid within a vehicle s thermal control loop. However, previous testing with a commercial mixture of PG and water containing phosphate corrosion inhibitors resulted in corrosion of aluminum within the test system and instability of the test fluid. This paper describes a follow-on long duration testing and analysis of 50% Propylene Glycol (PG)-based fluid and 50% de-ionized water mixture with inorganic corrosion inhibitors used in place of phosphates. The test evaluates the long-term fluid stability and resistance to microbial and chemical changes

  8. Functional binders for reversible lithium intercalation into graphite in propylene carbonate and ionic liquid media

    NASA Astrophysics Data System (ADS)

    Komaba, Shinichi; Yabuuchi, Naoaki; Ozeki, Tomoaki; Okushi, Koji; Yui, Hiroharu; Konno, Kozo; Katayama, Yasushi; Miura, Takashi

    Poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), and poly(vinyl alcohol) (PVA), which have oxygen species as functional groups, were utilized as a binder for graphite electrodes, and the electrochemical reversibility of lithium intercalation was examined in PC medium and ionic liquid electrolyte, lithium bis(trifluoromethanesulfonyl)amide dissolved in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide (BMP-TFSA). Columbic efficiency of 75-80% with more than 300 mAh g -1 was achieved upon first reduction/oxidation cycle in both electrolytes using these binding polymers, which were significantly improved in comparison to a conventional PVdF binder (less than 45% of columbic efficiency for the first cycle). For the graphite-PVdF electrode, co-intercalation and/or decomposition of PC molecules solvating to Li ions were observed by the electrochemical reduction, resulting in the cracking of graphite particles. In contrast, the co-intercalation and decomposition of PC molecules and BMP cations for the first reduction process were completely suppressed for the graphite electrodes prepared with the polymers containing oxygen atoms. It was proposed that the selective permeability of lithium ions was attained by the uniform coating of the graphite particles with PAA, PMA, and PVA polymers, because the electrostatic interaction between the positively charged lithium ions and negatively charged oxygen atom in the polymer should modulate the desolvation process of lithium ions during the lithium intercalation into graphite, showing the similar functions like artificial solid-electrolyte interphase.

  9. Recovery of propylene glycol from dilute aqueous solutions via reversible reaction with aldehydes

    SciTech Connect

    Broekhuis, R.R.; Lynn, S.; King, C.J. |

    1993-12-01

    A means is proposed for separating propylene glycol and other compounds bearing multiple hydroxyl groups by reversible chemical reaction. Glycols react with aldehydes in cyclic acetalization reactions to form substituted dioxolanes. Propylene glycol reacts with formaldehyde and acetaldehyde to form 4-methyl-1,3-dioxolane and 2,4-dimethyl-1,3-dioxolane. The reaction is catalyzed homogeneously by strong mineral acids or heterogeneously by cation exchange resins in the acid form. Separation processes utilizing this reaction would include an acetalization step, several distillative separation steps and finally a hydrolysis step in which the reaction is reversed. Both reaction steps must be forced to completion by removing the reaction product simultaneously. The equilibrium and kinetics of the reaction with formaldehyde were studied experimentally in systems catalyzed by Amberlite IR-120 ion exchange resin. A number of solvents were screened for their ability to extract 2,4-dimethyl-1,3-dioxolane from aqueous solution. Aromatic hydrocarbons exhibited the highest distribution into the organic phase. To achieve an effective separation of propylene glycol from aqueous solution by combined reaction with formaldehyde and distillation, formaldehyde would have to be present in excess and would be difficult and costly to separate from the aqueous solution. In reactive distillation using acetaldehyde as a reactant this is not a problem. A large flow of acetaldehyde would be necessary to recover the propylene glycol sufficiently in a distillative process. In a process combining reaction and extraction into an organic solvent this problem is avoided. Process simulation indicates the energy input of such a process is less than half of the energy required in a triple-effect evaporation process. This benefit is offset by higher capital costs and increased complexity in the reaction/extraction process.

  10. 78 FR 20032 - Styrene-Ethylene-Propylene Block Copolymer; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-03

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of styrene-ethylene-propylene block copolymer (CAS Reg. No. 108388-87-0) when used as an inert ingredient in a pesticide formulation. AgroFresh Inc., submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an exemption from the requirement of a tolerance. This......

  11. Smart poly(oligo(propylene glycol) methacrylate) hydrogel prepared by gamma radiation

    NASA Astrophysics Data System (ADS)

    Suljovrujic, E.; Micic, M.

    2015-01-01

    The synthesis of poly(oligo(propylene glycol) methacrylate) (POPGMA) from functionalised oligo(propylene glycol) methacrylate (OPGMA) monomers by gamma radiation-induced radical polymerisation is reported for the first time; POPGMA homopolymeric hydrogel with oligo(propylene glycol) (OPG) pendant chains, as a non-linear PPGMA-analogue, was synthesised from an monomer-solvent (OPGMA375-water/ethanol) mixture at different irradiation doses (5, 10, 25, and 40 kGy). Determination of the gel fraction was conducted after synthesis. The swelling properties of the POPGMA hydrogel were preliminarily investigated over wide pH (2.2-9.0) and temperature (4-70 °C) ranges. Additional characterisation of structure and properties was conducted by UV-vis and Fourier transform infrared (FTIR) spectroscopy as well as by differential scanning calorimetry (DSC). In order to evaluate the potential for biomedical applications, biocompatibility (cytocompatibility and haemolytic activity) studies were performed as well. Sol-gel conversion was relatively high for all irradiation doses, indicating radiation-induced synthesis as a good method for fabricating this hydrogel. Thermoresponsiveness and variations in swelling capacity as a result of thermosensitive OPG pendant chains with a lower critical solution temperature (LCST) were mainly observed below room temperature; thus, the volume phase transition temperature (VPTT) of POPGMA homopolymeric hydrogel is about 15 °C. Furthermore, POPGMA has satisfactory biocompatibility. The results indicate that the hydrogels with propylene glycol pendant chains can be easily prepared by gamma radiation and have potential for different applications as smart and biocompatible polymers.

  12. Propylene glycol monomethyl ether acetate (PGMEA) metabolism, disposition, and short-term vapor inhalation toxicity studies

    SciTech Connect

    Miller, R.R.; Hermann, E.A.; Young, J.T.; Calhoun, L.L.; Kastl, P.E.

    1984-09-30

    Male Fischer 344 rats were given a single po dose of approximately 8.7 mmol/kg of (1-14C)propylene glycol monomethyl ether acetate (PGMEA) or exposed to 3000 ppm (1-14C)PGMEA for 6 hr. After dosing, expired air, excreta, and tissues were analyzed for 14C activity, and metabolites in urine were isolated and identified. Approximately 64% of the administered 14C activity was eliminated as 14CO2 and about 24% was excreted in urine within 48 hr after a single po dose of radiolabeled PGMEA. Similarly, 53% was eliminated as 14CO2 and 26% was excreted in urine within 48 hr after the inhalation exposure. Propylene glycol, propylene glycol monomethyl ether (PGME), and the sulfate and glucuronide conjugates of PGME were identified as urinary metabolites after po dosing, as well as after inhalation exposure to PGMEA. The urinary metabolite profile and disposition of (14C)PGMEA were nearly identical to results previously obtained with propylene glycol monomethyl ether (PGME), indicating that PGMEA is rapidly and extensively hydrolyzed to PGME in vivo. A short-term vapor inhalation toxicity study in which male and female Fischer 344 rats and B6C3F1 mice were exposed to 0, 300, 1000, or 3000 ppm PGMEA confirmed that there were no substantial differences in the systemic effects of PGMEA as compared to PGME. However, histopathologic examination did reveal changes in the olfactory portions of the nasal mucosa of rats and mice exposed to PGMEA, which may be related to acetic acid resulting from hydrolysis of PGMEA in the nasal epithelium.

  13. Propylene glycol monomethyl ether acetate (PGMEA) metabolism, disposition, and short-term vapor inhalation toxicity studies.

    PubMed

    Miller, R R; Hermann, E A; Young, J T; Calhoun, L L; Kastl, P E

    1984-09-30

    Male Fischer 344 rats were given a single po dose of approximately 8.7 mmol/kg of [1-14C]propylene glycol monomethyl ether acetate (PGMEA) or exposed to 3000 ppm [1-14C]PGMEA for 6 hr. After dosing, expired air, excreta, and tissues were analyzed for 14C activity, and metabolites in urine were isolated and identified. Approximately 64% of the administered 14C activity was eliminated as 14CO2 and about 24% was excreted in urine within 48 hr after a single po dose of radiolabeled PGMEA. Similarly, 53% was eliminated as 14CO2 and 26% was excreted in urine within 48 hr after the inhalation exposure. Propylene glycol, propylene glycol monomethyl ether (PGME), and the sulfate and glucuronide conjugates of PGME were identified as urinary metabolites after po dosing, as well as after inhalation exposure to PGMEA. The urinary metabolite profile and disposition of [14C]PGMEA were nearly identical to results previously obtained with propylene glycol monomethyl ether (PGME), indicating that PGMEA is rapidly and extensively hydrolyzed to PGME in vivo. A short-term vapor inhalation toxicity study in which male and female Fischer 344 rats and B6C3F1 mice were exposed to 0, 300, 1000, or 3000 ppm PGMEA confirmed that there were no substantial differences in the systemic effects of PGMEA as compared to PGME. However, histopathologic examination did reveal changes in the olfactory portions of the nasal mucosa of rats and mice exposed to PGMEA, which may be related to acetic acid resulting from hydrolysis of PGMEA in the nasal epithelium. PMID:6474479

  14. Thermal Vacuum Test of GLAS Propylene Loop Heat Pipe Development Model

    NASA Technical Reports Server (NTRS)

    Baker, Charles; Butler, Dan; Ku, Jentung; Kaya, Tarik; Nikitkin, Michael

    2000-01-01

    This paper presents viewgraphs on Thermal Vacuum Tests of the GLAS (Geoscience Laser Altimeter System) Propylene Loop Heat Pipe Development Model. The topics include: 1) Flight LHP System (Laser); 2) Test Design and Objectives; 3) DM (Development Model) LHP (Loop Heat Pipe) Test Design; 4) Starter Heater and Coupling Blocks; 5) CC Control Heaters and PRT; 6) Heater Plates (Shown in Reflux Mode); 7) Startup Tests; 8) CC Control Heater Power Tests for CC Temperature Control; and 9) Control Temperature Stability.

  15. Old yellow enzyme: Reduction of nitrate esters, glycerin trinitrate, and propylene 1,2-dinitrate

    PubMed Central

    Meah, Younus; Brown, Bette Jo; Chakraborty, Sumita; Massey, Vincent

    2001-01-01

    The reaction of the old yellow enzyme and reduced flavins with organic nitrate esters has been studied. Reduced flavins have been found to react readily with glycerin trinitrate (GTN ) (nitroglycerin) and propylene dinitrate, with rate constants at pH 7.0, 25°C of 145 M−1s−1 and 5.8 M−1s−1, respectively. With GTN, the secondary nitrate was removed reductively 6 times faster than the primary nitrate, with liberation of nitrite. With propylene dinitrate, on the other hand, the primary nitrate residue was 3 times more reactive than the secondary residue. In the old yellow enzyme-catalyzed NADPH-dependent reduction of GTN and propylene dinitrate, ping-pong kinetics are displayed, as found for all other substrates of the enzyme. Rapid-reaction studies of mixing reduced enzyme with the nitrate esters show that a reduced enzyme–substrate complex is formed before oxidation of the reduced flavin. The rate constants for these reactions and the apparent Kd values of the enzyme–substrate complexes have been determined and reveal that the rate-limiting step in catalysis is reduction of the enzyme by NADPH. Analysis of the products reveal that with the enzyme-catalyzed reactions, reduction of the primary nitrate in both GTN and propylene dinitrate is favored by comparison with the free-flavin reactions. This preferential positional reactivity can be rationalized by modeling of the substrates into the known crystal structure of the enzyme. In contrast to the facile reaction of free reduced flavins with GTN, reduced 5-deazaflavins have been found to react some 4–5 orders of magnitude slower. This finding implies that the chemical mechanism of the reaction is one involving radical transfers. PMID:11438708

  16. [FTIR study on the synthesis of poly(propylene fumarate) and its copolymer].

    PubMed

    Zhang, Na; Cai, Zhong-yu; Chang, Jun-biao

    2010-01-01

    Poly(propylene fumarate) (PPF) is one kind of linear biodegradable polyester and the unsaturated double bonds along its main chain can be crosslinked with other olefinic monomers to form three-dimensional networks, and the networks can support tissues. In the present paper, firstly, the intermediate oligomer-bis (2-hydroxypropyl) fumarate (PFP) was synthesized, and then the unsaturated linear polyester PPF was synthesized with the oligomer PFP through melting condensation process. Additionally, on the base of the process, the oligomer bis(2-hydroxypropyl) sebacate (PSP) was synthesized by similar method and then a kind of new copolymer named poly(propylene fumarate-co-propylene sebacate) [P(PF-co-PS)] that comprised bis(2-hydroxypropyl) sebacate segments was synthesized with PFP and PSP by melting condensation. During the synthesis process, the structures of bis(2-hdroxypropyl) fumarate, bis(2-hydroxypropyl) sebacate, PPF and P(PF-co-PS) were characterized by FTIR The results shows that with the polymerization going along, oligomer bis (2-hydroxypropyl) fumarate and bis(2-hydroxypropyl) sebacate converted to PPF or P(PF-co-PS) gradually. PMID:20302075

  17. Science and the perceived environmental risk from ethylene glycol and propylene glycol

    SciTech Connect

    Snellings, W.M.; Shah, S.I.; Garska, D.; Williams, J.B.

    1994-12-31

    Ethylene glycol and propylene glycol are widely used in aircraft deicing fluids (ADF), heat transfer fluids, and engine coolants. Discharges of these compounds to the environment have been reduced in recent years, but remain significant. The perceived environmental risk affects the decisions of businesses and regulatory agencies. There is a perception that propylene glycol poses a lower environmental risk than ethylene glycol. This perception is an inference from the use of low concentrations of propylene glycol in food additives -- something safe for food must be safe for fish. Environmental risk, however, must be established on the basis of scientific data, including acute and chronic toxicity to freshwater and saltwater species, oxygen demand, and persistence. A review of aquatic toxicity data for marine and freshwater species, and a review of treatability data in wastewater and soil for these widely used compounds has been completed. The data show that the two compounds, in fact, pose similar environmental risks, and in certain aspects one or the other glycol appears to be preferable. All aspects must be considered to give a valid perception of risk. The role of additives in deicing fluids is significant. Environmental fate and effect data indicate that additives are usually more toxic than the glycols, and environmental data for particular formulations must be evaluated as part of any risk assessment.

  18. Synthesis and characterization of carboxymethyl xylan-g-poly(propylene oxide) and its application in films.

    PubMed

    Peng, Pai; Zhai, Meizhi; She, Diao; Gao, Yuefang

    2015-11-20

    Carboxymethyl xylan-g-poly(propylene oxide) (CMX-g-PPO) was successfully synthesized by grafting poly(propylene oxide) chains onto xylan from bamboo using the Al(Oi-Pr)3 initiated ring-opening polymerization of propylene oxides, followed by carboxymethylation with sodium chloroacetate under microwave irradiation. The synthesized CMX-g-PPO was well characterized by FT-IR, (13)C NMR, and AFM. The AFM imaging showed that the average sizes of xylan were 422.1×67.4×1.2nm, while the average sizes of grafting branches PPO were 128.0×38.5×5.1nm, which firstly provided an irrefutable and visual evidence for the structure of grafted xylan at single molecular level. Subsequently, a serial of CMX-g-PPO/CS films were prepared without addition of any plasticizers. The surface morphologies, wettability, water vapor barrier properties, mechanical properties, and thermal stabilities of the obtained films were characterized and compared with those of the control films by AFM, contact angle, WVP, tensile testing, and TGA, respectively. PMID:26344263

  19. Safety assessment of propylene glycol, tripropylene glycol, and PPGs as used in cosmetics.

    PubMed

    Fiume, Monice M; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2012-01-01

    Propylene glycol is an aliphatic alcohol that functions as a skin conditioning agent, viscosity decreasing agent, solvent, and fragrance ingredient in cosmetics. Tripropylene glycol functions as a humectant, antioxidant, and emulsion stabilizer. Polypropylene glycols (PPGs), including PPG-3, PPG-7, PPG-9, PPG-12, PPG-13, PPG-15, PPG-16, PPG-17, PPG-20, PPG-26, PPG-30, PPG-33, PPG-34, PPG-51, PPG-52, and PPG-69, function primarily as skin conditioning agents, with some solvent use. The majority of the safety and toxicity information presented is for propylene glycol (PG). Propylene glycol is generally nontoxic and is noncarcinogenic. Clinical studies demonstrated an absence of dermal sensitization at use concentrations, although concerns about irritation remained. The CIR Expert Panel determined that the available information support the safety of tripropylene glycol as well as all the PPGs. The Expert Panel concluded that PG, tripropylene glycol, and PPGs ≥3 are safe as used in cosmetic formulations when formulated to be nonirritating. PMID:23064775

  20. Recovery of propylene glycol from dilute aqueous solutions via reversible reaction with aldehydes

    SciTech Connect

    Broekhuis, R.R.; Lynn, S.; King, C.J. )

    1994-12-01

    The recovery of propylene glycol from dilute aqueous solutions via reaction with formaldehyde to form 4-methyl-1,3-dioxolane or with acetaldehyde to form 2,4-dimethyl-1,3-dioxolane was studied experimentally. The equilibrium and kinetics of the reaction with formaldehyde were studied in systems catalyzed by Amberlite IR-120 ion exchange resin. The equilibrium constant ranged from 5.9 to 8.7 in the temperature range from 25 to 85 C, with no obvious trend with respect to temperature. The kinetics was found to be first-order in the concentrations of propylene glycol, formaldehyde, and Amberlite IR-120, with an activation energy of 102 kJ/mol. In the reaction with acetaldehyde, the equilibrium constant decreased from 18.1 at 40 C to 8.5 at 83 C. The kinetics was faster than with formaldehyde. The volatilities of 4-methyl-1,3-dioxolane and 2,4-dimethyl-1,3-dioxolane relative to water were 100 and 33, respectively. Of several solvents screened, aromatic hydrocarbons exhibited the highest distribution of 2,4-dimethyl-1,3-dioxolane from the aqueous into the organic phase. Recovery of propylene glycol by reactive distillation with formaldehyde or acetaldehyde is hampered by unfavorable chemical and phase equilibria. A process combining reaction and extraction into an organic solvent appears to be more attractive and substantially reduces the energy requirement, in comparison with a triple-effect evaporation process.

  1. Catalytic oxidation of propylene--7. Use of temperature programmed reoxidation to characterize. gamma. -bismuth molybdate

    SciTech Connect

    Uda, T.; Lin, T.T.; Keulks, G.W.

    1980-03-01

    Temperature-programed reoxidation of propylene-reduced ..gamma..-Bi/sub 2/MoO/sub 6/ revealed a low-temperature peak (LTP) at 158/sup 0/C and a high-temperature peak (HTP) at 340/sup 0/C. Auger spectroscopy and X-ray diffraction of reduced and partially or completely reoxidized bismuth molybdate showed that at the LTP, molybdenum(IV) is oxidized to molybdenum(VI) and bismuth, from the metallic state to an oxidation state between zero and three, and that the HTP is associated with the complete oxidation of bismuth to bismuth(III). Activity tests for propylene oxidation showed lower acrolein formation on the catalyst, on which only the LTP was reoxidized than on catalysts on which both peaks were reoxidized. The reoxidation kinetics of the catalyst under conditions corresponding to the LTP showed an activation energy of 22.9 kcal/mole below 170/sup 0/C and near zero above 170/sup 0/C; the break in the Arrhenius plot of reoxidation of the catalyst under conditions corresponding to the HTP was at 400/sup 0/C, with activation energies of 46 kcal/mole at lower and near zero at higher temperatures. Propylene oxidation was apparently rate-limited by the HTP reoxidation process below 400/sup 0/C and by allylic hydrogen abstraction above 400/sup 0/C.

  2. Atmospheric chemistry of toxic contaminants 2. Saturated aliphatics: Acetaldehyde, dioxane, ethylene glycol ethers, propylene oxide

    SciTech Connect

    Grosjean, D. )

    1990-11-01

    Detailed mechanisms are outlined for the chemical reactions that contribute to in-situ formation and atmospheric removal of the saturated aliphatic contaminants acetaldehyde, dioxane, ethylene glycol ethers (methyl, ethyl, n-butyl) and propylene oxide. In-situ formation is of major importance for acetaldehyde. In-situ removal involves reaction with OH (all compounds) and, for acetaldehyde, photolysis and reaction with NO{sub 3}. Acetaldehyde, dioxane, and the ethers are rapidly removed (half-lives of less than one day), leading to PAN (acetaldehyde) and to 2-oxodioxane and formaldehyde (dioxane). Reaction products of the glycol ethers include a large number of hydroxyesters, hydroxyacids, and hydroxycarbonyls. Propylene oxide reacts only slowly with OH, with an atmospheric half-life of 3 - 10 days, to yeild formaldehyde, acetaldehyde, and PAN. Uncertainties in the reaction mechanisms for dioxane, the glycol ethers, and propylene oxide are discussed and include C-C vs C-O bond scission in alkoxy radicals as well as alkoxy radical unimolecular decomposition vs reaction with oxygen.

  3. Degradation kinetics of electron beam irradiated poly(propylene-co-ethylene) heterophasic copolymer

    NASA Astrophysics Data System (ADS)

    Koosha, Mojtaba; Ebrahimi, Nastaran; Jahani, Yousef; Sajjadi, Seyed Abolfazl Seyed

    2011-07-01

    This study considers the effects of electron beam radiation on degradation kinetics of a poly(propylene-co-ethylene) heterophasic copolymer. Polypropylene heterophasic copolymers are composed of ethylene-propylene rubbery phase dispersed in crystalline polypropylene homopolymer matrix. Electron beam radiation can affect both polypropylene homopolymer matrix and ethylene-propylene dispersed phases simultaneously. Both phases undergo degradation and crosslinking reactions, but degradation is more probable in the polypropylene homopolymer matrix. The aim of this work is to study kinetics of degradation in this material. A high power electron accelerator irradiated raw samples under nitrogen atmosphere. The samples are analyzed using TGA in non-isothermal mode, and the degradation kinetic parameters were determined using Kissinger, Flynn-Wall-Ozawa and Coats-Redfern methods. The kinetic parameters resulted from these methods are compared. Results of kinetics studies show that orders of degradation reactions occurring in nitrogen atmosphere are all less than one. It indicates degradation takes place due to thermal dissociation of the chemical bonds.

  4. Pyrazolylamidino ligands from coupling of acetonitrile and pyrazoles: a systematic study.

    PubMed

    Gómez-Iglesias, Patricia; Arroyo, Marta; Bajo, Sonia; Strohmann, Carsten; Miguel, Daniel; Villafañe, Fernando

    2014-12-01

    Mixed pyrazole-acetonitrile complexes, both neutral fac-[ReBr(CO)3(NCMe)(pz*H)] (pz*H = pzH, pyrazole; dmpzH, 3,5-dimethylpyrazole; or indzH, indazole) and cationic fac-[Re(CO)3(NCMe)(pz*H)2]A (A = BF4, ClO4, or OTf), are described. Their role as the only starting products to obtain final pyrazolylamidino complexes fac-[ReBr(CO)3(NH═C(Me)pz*-κ(2)N,N)] and fac-[Re(CO)3(pz*H)(NH═C(Me)pz*-κ(2)N,N)]A, respectively, is examined. Other products involved in the processes, such as fac-[ReBr(CO)3(pz*H)2], fac-[Re(CO)3(NCMe)(NH═C(Me)pz*-κ(2)N,N)]A, and fac-[Re(CO)3(pz*H)2(OTf)] are also described. Warming CD3CN solutions of fac-[Re(CO)3(NCMe)(pz*H)2]A at 40 °C gives cleanly the pyrazolylamidino complexes [Re(CO)3(pz*H)(NH═C(Me)pz*-κ(2)N,N)]A as the only products, pointing to an intramolecular process. This is confirmed by carrying out reactions in the presence of one equivalent of a pyrazole different from that coordinated, which affords complexes where the pyrazolylamidino ligand contains only the pyrazole previously coordinated. When the reactions lead to an equilibrium mixture of the final and starting products, the reverse reaction gives the same equilibrium mixture, which indicates that the coupling reaction of pyrazoles and nitriles to obtain pyrazolylamidino ligands is a reversible intramolecular process. A systematic study of the possible factors which may affect the reaction gives the following results: (a) the yields of the direct reactions are higher for lower temperatures; (b) the tendency of the pyrazoles to give pyrazolylamidino complexes follows the sequence indzH > pzH > dmpzH; and (c) the reaction rates do not depend on the nature of the anion even when a large excess is added. The presence of a small amount of aqueous solution of NaOH catalyzes the reaction. Thus, addition of 0.5-1% of NaOH (aq) to solutions of fac-[ReBr(CO)3(NCMe)(pz*H)] (in CD3CN) or fac-[Re(CO)3(NCMe)(pz*H)2]A (in CD3CN, CD3NO2 or (CD3)2CO) allowed the syntheses of the

  5. Electrolyte Solvation and Ionic Association. V. Acetonitrile-Lithium Bis(fluorosulfonyl)imide (LiFSI) Mixtures

    SciTech Connect

    Han, Sang D.; Borodin, Oleg; Seo, D. M.; Zhou, Zhi B.; Henderson, Wesley A.

    2014-09-30

    Electrolytes with the salt lithium bis(fluorosulfonyl)imide (LiFSI) have been evaluated relative to comparable electrolytes with other lithium salts. Acetonitrile (AN) has been used as a model electrolyte solvent. The information obtained from the thermal phase behavior, solvation/ionic association interactions, quantum chemical (QC) calculations and molecular dynamics (MD) simulations (with an APPLE&P many-body polarizable force field for the LiFSI salt) of the (AN)n-LiFSI mixtures provides detailed insight into the coordination interactions of the FSI- anions and the wide variability noted in the electrolyte transport property (i.e., viscosity and ionic conductivity).

  6. Rapid processing of carbon-carbon composites by forced flow-thermal gradient chemical vapor infiltration (FCVI)

    SciTech Connect

    Vaidyaraman, S.; Lackey, W.J.; Agrawal, P.K.; Freeman, G.B.; Langman, M.D.

    1995-10-01

    Carbon fiber-carbon matrix composites were fabricated using the forced flow-thermal gradient chemical vapor infiltration (FCVI) process. Preforms were prepared by stacking 40 layers of plain weave carbon cloth in a graphite holder. The preforms were infiltrated using propylene, propane, and methane. The present work showed that the FCVI process is well suited for fabricating carbon-carbon composites; without optimization of the process, the authors have achieved uniform and thorough densification. Composites with porosities as low as 7% were fabricated in 8--12 h. The highest deposition rate obtained in the present study was {approximately}3 {micro}m/h which is more than an order of magnitude faster than the typical value of 0.1--0.25 {micro}m/h for the isothermal process. It was also found that the use of propylene and propane as reagents resulted in faster infiltration compared to methane.

  7. Combined crossed molecular beam and ab initio investigation of the multichannel reaction of boron monoxide (BO; X2Σ+) with Propylene (CH3CHCH2; X1A'): competing atomic hydrogen and methyl loss pathways.

    PubMed

    Maity, Surajit; Dangi, Beni B; Parker, Dorian S N; Kaiser, Ralf I; An, Yi; Sun, Bing-Jian; Chang, A H H

    2014-10-16

    The reaction dynamics of boron monoxide ((11)BO; X(2)Σ(+)) with propylene (CH(3)CHCH(2); X(1)A') were investigated under single collision conditions at a collision energy of 22.5 ± 1.3 kJ mol(-1). The crossed molecular beam investigation combined with ab initio electronic structure and statistical (RRKM) calculations reveals that the reaction follows indirect scattering dynamics and proceeds via the barrierless addition of boron monoxide radical with its radical center located at the boron atom. This addition takes place to either the terminal carbon atom (C1) and/or the central carbon atom (C2) of propylene reactant forming (11)BOC(3)H(6) intermediate(s). The long-lived (11)BOC(3)H(6) doublet intermediate(s) underwent unimolecular decomposition involving at least three competing reaction mechanisms via an atomic hydrogen loss from the vinyl group, an atomic hydrogen loss from the methyl group, and a methyl group elimination to form cis-/trans-1-propenyl-oxo-borane (CH(3)CHCH(11)BO), 3-propenyl-oxo-borane (CH(2)CHCH(2)(11)BO), and ethenyl-oxo-borane (CH(2)CH(11)BO), respectively. Utilizing partially deuterated propylene (CD(3)CHCH(2) and CH(3)CDCD(2)), we reveal that the loss of a vinyl hydrogen atom is the dominant hydrogen elimination pathway (85 ± 10%) forming cis-/trans-1-propenyl-oxo-borane, compared to the loss of a methyl hydrogen atom (15 ± 10%) leading to 3-propenyl-oxo-borane. The branching ratios for an atomic hydrogen loss from the vinyl group, an atomic hydrogen loss from the methyl group, and a methyl group loss are experimentally derived to be 26 ± 8%:5 ± 3%:69 ± 15%, respectively; these data correlate nicely with the branching ratios calculated via RRKM theory of 19%:5%:75%, respectively. PMID:25238644

  8. Carbons for lithium ion cells prepared using sepiolite as an inorganic template.

    SciTech Connect

    Sandi, G.

    1998-12-09

    Carbon anodes for Li ion cells have been prepared by the in situ polymerization of olefins such as propylene and ethylene in the channels of sepiolite clay mineral. Upon dissolution of the inorganic framework, a disordered carbon was obtained. The carbon was tested as anode in coin cells, yielding a reversible capacity of 633 mAh/g, 1.70 times higher than the capacity delivered by graphitic carbon, assuming 100% efficiency. The coulombic efficiency was higher than 90%.

  9. On-column nitrosation of amines observed in liquid chromatography impurity separations employing ammonium hydroxide and acetonitrile as mobile phase.

    PubMed

    Myers, David P; Hetrick, Evan M; Liang, Zhongming; Hadden, Chad E; Bandy, Steven; Kemp, Craig A; Harris, Thomas M; Baertschi, Steven W

    2013-12-01

    The availability of high performance liquid chromatography (HPLC) columns capable of operation at pH values up to 12 has allowed a greater selectivity space to be explored for method development in pharmaceutical analysis. Ammonium hydroxide is of particular value in the mobile phase because it is compatible with direct interfacing to electrospray mass spectrometers. This paper reports an unexpected N-nitrosation reaction that occurs with analytes containing primary and secondary amines when ammonium hydroxide is used to achieve the high pH and acetonitrile is used as the organic modifier. The nitrosation reaction has generality. It has been observed on multiple columns from different vendors and with multiple amine-containing analytes. Ammonia was established to be the source of the nitroso nitrogen. The stainless steel column frit and metal ablated from the frit have been shown to be the sites of the reactions. The process is initiated by removal of the chromium oxide protective film from the stainless steel by acetonitrile. It is hypothesized that the highly active, freshly exposed metals catalyze room temperature oxidation of ammonia to NO but that the actual nitrosating agent is likely N(2)O(3). PMID:24182763

  10. Isomerization and fragmentation of acetonitrile upon interaction with N(4S) atoms: the chemistry of nitrogen in dense molecular clouds

    NASA Astrophysics Data System (ADS)

    Mencos, Alejandro; Krim, Lahouari

    2016-08-01

    We experimentally show that the reaction between ground state nitrogen atoms N(4S) and acetonitrile CH3CN can lead to two distinct chemical pathways that are both thermally activated at very low temperatures. First is CH3CN isomerization which produces CH3NC and H2CCNH. Second is CH3CN decomposition which produces HNC and CH3CNH+CN- fragments, with the possible release of H2. Our results reveal that the mobility of N(4S)-atoms is stimulated in the 3-11 K temperature range, and that its subsequent encounter with one acetonitrile molecule is sufficient for the aforementioned reactions to occur without the need for additional energy to be supplied to the CH3CN + N(4S) system. These findings shed more light on the nitrogen chemistry that can possibly take place in dense molecular clouds, which until now was thought to only involve high-energy processes and therefore be unlikely to occur in such cold and dark interstellar regions. The reaction pathways we propose in this study have very important astrochemical implications, as it was shown recently that the atomic nitrogen might be more abundant, in many interstellar icy grain mantles, than previously thought. Also, these reaction pathways can now be considered within dense molecular clouds, and possibly affect the branching ratios for N-bearing molecules computed in astrochemical modelling.

  11. Structure of and hydrogen bonding in a 3:2 inclusion compound of N-methylmorpholine betaine hydrochloride with acetonitrile

    NASA Astrophysics Data System (ADS)

    Dega-Szafran, Z.; Szafran, M.; Antkowiak, A.; Grundwald-Wyspianska, M.; Nowak, E.; Gdaniec, M.; Kosturkiewicz, Z.

    2002-03-01

    N-Methylmorpholine betaine hydrochloride (MMB·HCl) forms a 3:2 inclusion compound with acetonitrile. The crystal structure of the compound has been determined at 100 K from a twinned crystal to be trigonal with the space group Poverline3; a= b=16.767(2), c=6.996(1) Å, γ=120°. The host framework is constructed from the ionic pairs formed by the chlorine anion and the protonated, at the carboxylate group, betaine cation. The cation and anion are joined by the O-H⋯Cl - hydrogen bond of the length 2.974(2) Å and angle 173(3)°. The guest molecules are included in two kinds of channels formed in the host matrix. The narrow channel runs parallel to the z axis at x=2/3, y=1/3 and is filled with acetonitrile molecules situated at the three-fold axis. The second channel, also parallel to the z axis, joins large cavities with the center at 0,0,1/2 of overline3 symmetry. The cavity accommodates two guest molecules which exhibit disorder in the crystal. There are only van der Waals interactions between the host and the guest. FTIR spectra of MMB·HCl and its deuterated analog have been discussed.

  12. Infrared spectra and structure of isomeric (cyanophenyl)acetonitriles and their carbanions: an ab initio force field treatment

    NASA Astrophysics Data System (ADS)

    Binev, I. G.; Tsenov, J. A.; Velcheva, E. A.; Radomirska, V. B.; Juchnovski, I. N.

    1996-05-01

    The structures of o-, m- and p-(cyanophenyl)acetonitrile molecules and their carbanions were studied on the basis of infrared spectroscopic data and ab initio force field calculations. The assignment was given for the 3100-1100 cm -1 bands of the substances studied. The scaled theoretical infrared band frequencies agree well with those measured experimentally. An excellent linear correlation ( R = 0.999) was found between the theoretical and experimental vCN frequencies of both molecules and carbanions. The calculations predict well the strong increase in intensity (1.5- to 70-fold) of the vCN, v8 and v19 bands, which accompanies the conversion of the isomeric (cyanophenyl)acetonitrile molecules into the corresponding carbanions. The structures of the lithium, sodium and potassium derivatives of the nitriles studied in dimethyl sulphoxide are close to those of the kinetically free carbanions. The carbanionic centres are practically planar; the cyano groups carry considerable negative charges, but their influences on the carbanionic centres are mainly inductive. The carbanionic charges are delocalized over the phenylene rings (0.35-0.40 e-), methide (0.22-0.29 e-), α-cyano (0.24-0.27 e-) and ring-cyano (0.08-0.14 e-) groups.

  13. Direct Determination of Equilibrium Potentials for Hydrogen Oxidation/Production by Open Circuit Potential Measurements in Acetonitrile

    SciTech Connect

    Roberts, John A. S.; Bullock, R. Morris

    2013-04-01

    Open circuit potentials were measured for acetonitrile solutions of a variety of acids and their conjugate bases under 1 atm H2. Acids examined were triethylammonium, dimethylformamidium, 2,6-dichloroanilinium, 4-cyanoanilinium, 4-bromoanilinium, and 4-anisidinium salts. These potentials, along with the pKa values of the acids, establish the value of the standard hydrogen electrode (SHE) potential in acetonitrile as -0.028(4) V vs the ferrocenium/ferrocene couple. Dimethylformamidium forms homoconjugates and other aggregates with dimethylformamide; open circuit potentials (OCPs) were used to quantify the extent of these reactions. Overpotentials for electrocatalytic hydrogen production and oxidation were determined from open circuit potentials and voltammograms of acidic or basic catalyst solutions under H2. For these solutions, agreement between OCP values and potentials calculated using the Nernst equation is within 12 mV. Finally, use of the measured equilibrium potential allows direct comparison of catalytic systems in different media; it requires neither pKa values, homoconjugation constants, nor the SHE potential.

  14. Mutagenic activity of the products of ozone reaction with propylene in the presence and absence of nitrogen dioxide

    SciTech Connect

    Shepson, P.B.; Kleindienst, T.E.; Edney, E.O.; Cuplitt, L.T.; Claxton, L.D.

    1985-11-01

    This study was performed to determine if propylene reaction with ozone could account for the large mutagenic activity we have observed in irradiated propylene/NO/sub x/ mixtures. In a 22.7-m/sup 3/ flow mode smog chamber, 5.4 ppm of propylene was allowed to react with 0.9 ppm of ozone either in the presence or in the absence of 0.2 ppm of nitrogen dioxide (at 25 /sup 0/C in the dark). The steady-state reactant and product distribution was then tested for total mutagenic activity by exposing Salmonella typhimurium strain TA100 to the gas-phase chamber effluent. The total product dosage in the test plates was varied by exposing them for 0, 5, 10, 15, and 20 h. Salmonella typhimurium survivor levels were obtained at each length of exposure. The number of revertants per plate increased at a rate of approx. 4-5 per hour, while the survivor level decreased throughout the exposure. Most of the total mutagenic activity can be accounted for by the presence of formaldehyde. The total mutagenic activity observed was, however, much smaller than that observed in the irradiated propylene/NO/sub x/ system, for comparable amounts of propylene consumed.

  15. Infrared cross-sections and integrated band intensities of propylene: Temperature-dependent studies

    NASA Astrophysics Data System (ADS)

    Es-sebbar, Et-touhami; Alrefae, Majed; Farooq, Aamir

    2014-01-01

    Propylene, a by-product of biomass burning, thermal cracking of hydrocarbons and incomplete combustion of fossil fuels, is a ubiquitous molecule found in the environment and atmosphere. Accurate infrared (IR) cross-sections and integrated band intensities of propylene are essential for quantitative measurements and atmospheric modeling. We measured absolute IR cross-sections of propylene using Fourier Transform Infrared (FTIR) Spectroscopy over the wavenumber range of 400-6500 cm-1 and at gas temperatures between 296 and 460 K. We recorded these spectra at spectral resolutions ranging from 0.08 to 0.5 cm-1 and measured the integrated band intensities for a number of vibrational bands in certain spectral regions. We then compared the integrated band intensities measured at room temperature with values derived from the National Institute of Standards and Technology (NIST) and the Pacific Northwest National Laboratory (PNNL) databases. Our results agreed well with the results reported in the two databases with a maximum deviation of about 4%. The peak cross-sections for the primary bands decreased by about 20-54% when the temperature increased from 296 to 460 K. Moreover, we determined the integrated band intensities as a function of temperature for certain features in various spectral regions; we found no significant temperature dependence over the range of temperatures considered here. We also studied the effect of temperature on absorption cross-section using a Difference Frequency Generation (DFG) laser system. We compared the DFG results with those obtained from the FTIR study at certain wavenumbers over the 2850-2975 cm-1 range and found a reasonable agreement with less than 10% discrepancy.

  16. Quantifying Residues from Postharvest Propylene Oxide Fumigation of Almonds and Walnuts.

    PubMed

    Jimenez, Leonel R; Hall, Wiley A; Rodriquez, Matthew S; Cooper, William J; Muhareb, Jeanette; Jones, Tom; Walse, Spencer S

    2015-01-01

    A novel analytical approach involving solvent extraction with methyl tert-butyl ether (MTBE) followed by GC was developed to quantify residues that result from the postharvest fumigation of almonds and walnuts with propylene oxide (PPO). Verification and quantification of PPO, propylene chlorohydrin (PCH) [1-chloropropan-2-ol (PCH-1) and 2-chloropropan-1-ol (PCH-2)], and propylene bromohydrin (PBH) [1-bromopropan-2-ol (PBH-1) and 2-bromopropan-1-ol (PBH-2)] was accomplished with a combination of electron impact ionization MS (EIMS), negative ion chemical ionization MS (NCIMS), and electron capture detection (ECD). Respective GC/EIMS LOQs for PPO, PCH-1, PCH-2, PBH-1, and PBH-2 in MTBE extracts were [ppm (μg/g nut)] 0.9, 2.1, 2.5, 30.3, and 50.0 for almonds and 0.8, 2.2, 2.02, 41.6, and 45.7 for walnuts. Relative to GC/EIMS, GC-ECD analyses resulted in no detection of PPO, similar detector responses for PCH isomers, and >100-fold more sensitive detection of PBH isomers. NCIMS did not enhance detection of PBH isomers relative to EIMS and was, respectively, approximately 20-, 5-, and 10-fold less sensitive to PPO, PCH-1, and PCH-2. MTBE extraction efficiencies were >90% for all analytes. The 10-fold concentration of MTBE extracts yielded recoveries of 85-105% for the PBH isomers and a concomitant decrease in LODs and LOQs across detector types. The recoveries of PCH isomers and PPO in the MTBE concentrate were relatively low (approximately 50 to 75%), which confound improvements in LODs and LOQs regardless of detector type. PMID:26525262

  17. Hydride, hydrogen atom, proton, and electron transfer driving forces of various five-membered heterocyclic organic hydrides and their reaction intermediates in acetonitrile.

    PubMed

    Zhu, Xiao-Qing; Zhang, Ming-Tian; Yu, Ao; Wang, Chun-Hua; Cheng, Jin-Pei

    2008-02-27

    weak one-electron oxidation agents. The energies of the intramolecular hydrogen bond in 3H, 3H+*, and 3* with a hydroxyl group at ortho-position on the 2-phenyl ring were estimated by using experimental method, the results disclose that the hydrogen bond energy is 3.2, 2.8-3.0, and 3.9-4.0 kcal/mol for 3H, 3H+*, and 3* in acetonitrile, respectively, which is favorable for hydrogen atom transfer but unfavorable for hydride transfer from 3H. The relative effective charges on the active center in ZH, ZH+*, Z*, and Z+, which is an efficient measurement of electrophilicity or nucleophilicity as well as dimerizing ability of a chemical species, were estimated by using experimental method; the results indicate that 1*-5* belong to electron-sufficient carbon-radicals, 6*-7* belong to electron-deficient carbon radicals, they are all difficult to dimerize, and that 1+-5+ belong to weak electrophilic agents, 6+-7+ belong to strong electrophilic agents. All these information disclosed in this work could not only supply a gap of the chemical thermodynamics of the five-membered heterocyclic compounds as organic hydride donors, but also strongly promote the fast development of the chemistry and applications of the five-membered heterocyclic organic hydrides. PMID:18254624

  18. Photoelectrochemistry of the thallic/thallous couple - The thallic ion catalyzed photo-oxidation of propylene

    NASA Astrophysics Data System (ADS)

    Switzer, J. A.; Moorehead, E. L.; Dalesandro, D. M.

    1982-10-01

    Liquid-junction photovoltaic and photoelectrosynthetic applications of the thallic/thallous couple have been investigated. In the liquid-junction photovoltaic mode the redox couple produces large photovoltages with several semiconductors (TiO2, MoS2, CdS, and GaAs), and does not absorb appreciable semiconductor ultra-bandgap light. The couple also shows photoelectrosynthetic utility, since the thallic ion is a selective two-electron oxidizing agent for a variety of organic substrates. Preliminary work on the photoassisted epoxidation of propylene at n-type semiconductor electrodes (TiO2) and powders (TiO2, WO3, and ZnO) is discussed.

  19. Radiation graft modification of ethylene-propylene rubber—II. Effect of additives

    NASA Astrophysics Data System (ADS)

    Haddadi-Asl, V.; Burford, R. P.; Garnett, J. L.

    1995-02-01

    The effect of multifunctional acrylic additives including TMPTA, PEGDA and PGTA on the radiation grafting of hydrophilic vinyl monomers onto ethylene—propylene elastomer (EPM rubbers) was studied. This work centres upon gamma irradiation-induced grafting of acrylamide (AAm), N-vinyl-2-pyrrolidone (NVP), 2-hydroxyethyl methacrylate (HEMA) and acrylonitrile (AN) onto EPM rubber by the simultaneous method. Water proved to be an effective solvent but methanol lowered grafting. Sulphuric acid was detrimental to both homopolymerisation and grafting, a result consistent with the theory proposed for the role of this additive in polymer grafting systems.

  20. Multiresidue pesticide analysis of botanical dietary supplements using salt-out acetonitrile extraction, solid-phase extraction cleanup column, and gas chromatography-triple quadrupole mass spectrometry.

    PubMed

    Hayward, Douglas G; Wong, Jon W; Shi, Feng; Zhang, Kai; Lee, Nathaniel S; DiBenedetto, Alex L; Hengel, Mathew J

    2013-05-01

    Dietary supplements form an increasing part of the American diet, yet broadly applicable multiresidue pesticide methods have not been evaluated for many of these supplements. A method for the analysis of 310 pesticides, isomers, and pesticide metabolites in dried botanical dietary supplements has been developed and validated. Sample preparation involved acetonitrile:water added to the botanical along with anhydrous magnesium sulfate and sodium chloride for extraction, followed by cleanup with solid-phase extraction using a tandem cartridge consisting of graphitized carbon black (GCB) and primary-secondary amine sorbent (PSA). Pesticides were measured by gas chromatography-tandem mass spectrometry. Accuracy and precision were evaluated through fortifications of 24 botanicals at 10, 25, 100, and 500 μg/kg. Mean pesticide recoveries and relative standard deviations (RSDs) for all botanicals were 97%, 91%, 90%, and 90% and 15%, 10%, 8%, and 6% at 10, 25, 100, and 500 μg/kg, respectively. The method was applied to 21 incurred botanicals. Quinoxyfen was measured in hops (100-620 μg/kg). Tetraconazole (48 μg/kg), tetramethrin (15 μg/kg), methamidophos (50 μg/kg), and chlorpyrifos (93 μg/kg) were measured in licorice, mallow, tea, and tribulus, respectively. Quintozene, its metabolites and contaminants (pentachloroaniline, pentachlorobenzene, pentachloroanisole, and pentachlorothioanisole and hexachlorobenzene and tecnazene, respectively), with hexachlorocyclohexanes and DDT were identified in ginseng sources along with azoxystrobin, diazinon, and dimethomorph between 0.7 and 2800 μg/kg. Validation with these botanicals demonstrated the extent of this method's applicability for screening 310 pesticides in a wide array of botanical dietary supplements. PMID:23534560

  1. Utilization of Cyanoacetohydrazide and Oxadiazolyl Acetonitrile in the Synthesis of Some New Cytotoxic Heterocyclic Compounds.

    PubMed

    Shaker, Soheir A; Marzouk, Magda I

    2016-01-01

    A (pyridazinyl)acetate derivative was reacted with thiosemicarbazide and hydrazine hydrate to yield spiropyridazinone and acetohydrazide derivatives, respectively. The acetohydrazide derivative was used as a starting material for synthesizing some new heterocyclic compounds such as oxoindolinylidene, dimethylpyrazolyl, methylpyrazolyl, oxopyrazolyl, cyanoacetylacetohydrazide and oxadiazolylacetonitrile derivatives. The behavior of the cyanoacetylacetohydrazide and oxadiazolylacetonitrile derivatives towards nitrogen and carbon nucleophiles was investigated. The assigned structures of the prepared compounds were elucidated by spectral methods (IR, ¹H-NMR (13)C-NMR and mass spectroscopy). Some of the newly prepared compounds were tested in vitro against a panel of four human tumor cell lines, namely hepatocellular carcinoma (liver) HePG-2, colon cancer HCT-116, human prostate cancer PC3, and mammary gland breast MCF-7. Also they were tested as antioxidants. Almost all of the tested compounds showed satisfactory activity. PMID:26840279

  2. Hydrogenolysis of Glycerol to Propylene Glycol on Nanosized Cu-Zn-Al Catalysts Prepared Using Microwave Process.

    PubMed

    Kim, Dong Won; Ha, Sang Ho; Moon, Myung Jun; Lim, Kwon Taek; Ryu, Young Bok; Lee, Sun Do; Lee, Man Sig; Hong, Seong-Soo

    2015-01-01

    Cu-Zn-Al catalysts were prepared using microwave-assisted process and co-precipitation methods. The prepared catalysts were characterized by XRD, BET, XPS and TPD of ammonia and their catalytic activity for the hydrogenolysis of glycerol to propylene glycol was also examined. The XRD patterns of Cu/Zn/Al mixed catalysts show CuO and ZnO crystalline phase regardless of preparation method. The highest glycerol hydrogenolysis conversion is obtained with the catalyst having a Cu/Zn/Al ratio of 2:2:1. Hydrogen pre-reduction of catalysts significantly enhanced both glycerol conversions and selectivity to propylene glycol. The glycerol conversion increased with an increase of reaction temperature. However, the selectivity to propylene glycol increased with an increase of temperature, and then declined to 30.5% at 523 K. PMID:26328420

  3. The effect of glycerol, propylene glycol and polyethylene glycol 400 on the partition coefficient of benzophenone-3 (oxybenzone).

    PubMed

    Mbah, C J

    2007-01-01

    Sunscreen products are widely used to protect the skin from sun-related deleterious effects. The objective of the study was to investigate the potential effect of glycerol, propylene glycol and polyethylene glycol 400 on dermal absorption of oxybenzone by studying their effects on its partition coefficient. The partition coefficient was evaluated in a chloroform-water system at room temperature. It was found that glycerol and propylene glycol decreased the partition coefficient of oxybenzone, while an increase in partition coefficient was observed with polyethylene glycol 400. The findings suggest that polyethylene glycol 400 in contrast to glycerol and propylene glycol has the potential of increasing the vehicle-skin partition coefficient of oxybenzone when cosmetic products containing such an UV absorber are topically applied to the skin. PMID:17294811

  4. Distribution of pesticides in n-hexane/water and n-hexane/acetonitrile systems and estimation of possibilities of their extraction isolation and preconcentration from various matrices.

    PubMed

    Zayats, M F; Leschev, S M; Petrashkevich, N V; Zayats, M A; Kadenczki, L; Szitás, R; Szemán Dobrik, H; Keresztény, N

    2013-04-24

    Distribution of 150 most widely used pesticides of different chemical classes (amides, anilinopirimidines, aromatics, benzenesulfonates, carbamates, dicarboximides, organophosphorus compounds, phenyl esters, phenylureas, pyrazoles, pyrethroids, pyrimidines, strobilurins, sulfamides, triazines, triazoles, etc.) in n-hexane/water and n-hexane/acetonitrile systems was investigated at 25°C. Distribution constants of pesticides (P) have been calculated as ratio of pesticide concentration in n-hexane to its concentration in water or acetonitrile phase. HPLC and GC methods were used for pesticides determination in phases. It was found that the overwhelming majority of pesticides are hydrophobic, i.e. in n-hexane/water system LgP≫0, and the difference in LgP values can reach 9.1 units. Replacement of water for acetonitrile leads to dramatic fall of LgP values reaching 9.5 units. The majority of LgP values in this case are negative and their differences is strongly leveled in comparison with a hexane/water system. Thus, maximal difference in pesticides LgP values for n-hexane/acetonitrile system is 3.2 units. It is shown that n-hexane can be used for selective and efficient extraction and preconcentration of pesticides from water matrices. On the other hand, acetonitrile is effective for the isolation and preconcentration of pesticides from hydrocarbon and vegetable oil matrices. The distribution constants described in the paper may be effectively used for the estimation of possibilities of extraction isolation, preconcentration and separation of pesticides. PMID:23567114

  5. Microviscosity in Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer micelles

    SciTech Connect

    Nivaggioli, T.; Tsao, B.; Alexandridis, P.; Hatton, T.A. )

    1995-01-01

    The micellar microviscosity afforded by Pluronic and Tetronic poly(ethylene oxide)-poly(propylene oxide) block copolymer aqueous solutions has been investigated by fluorescence and NMR spectroscopy. Comparison is made with bulk poly(propylene oxide) (PPO) samples of different molecular weights. The microviscosity in Pluronic PEO-PPO-PEO copolymer micelles is much larger than that observed in conventional surfactant micelles and depends strongly on the size of the hydrophobic PPO block: the larger this block, the higher the viscosity. Above the critical micellar temperature (CMT), as temperature increases, the microviscosity decreases. However, this decrease is not as important as that observed in bulk PPO. Hence, the relative microviscosity, defined as the ratio of the two observed phenomena, increases. This suggests structural transformation of the micelles resulting in a core becoming more and more compact as temperature increases. Such results have been confirmed by NMR studies that showed broadening of the PPO peak and relatively constant spin-lattice relaxation time, T[sub i], with increasing temperature while the PEO signal remained relatively sharp with an exponential increase in T[sub 1]. 30 refs., 9 figs., 1 tab.

  6. Electrochemical Interrogation of G3-Poly(propylene thiophenoimine) Dendritic Star Polymer in Phenanthrene Sensing

    PubMed Central

    Makelane, Hlamulo R.; Tovide, Oluwakemi; Sunday, Christopher E.; Waryo, Tesfaye; Iwuoha, Emmanuel I.

    2015-01-01

    A novel dendritic star-copolymer, generation 3 poly(propylene thiophenoimine) (G3PPT)-co-poly(3-hexylthiophene) (P3HT) star co-polymer on gold electrode (i.e., Au|G3PPT-co-P3HT) was used as a sensor system for the determination of phenanthrene (PHE). The G3PPT-co-P3HT star co-polymer was synthesized via in situ electrochemical co-polymerization of generation 3 poly (propylene thiophenoimine) and poly (3-hexylthiophene) on gold electrode. 1HNMR spectroscopy was used to determine the regioregularity of the polymer composites, whereas Fourier transform infrared spectroscopy and scanning electron microscopy were used to study their structural and morphological properties. Au|G3PPT-co-P3HT in the absence of PHE, exhibited reversible electrochemistry attributable to the oligo (thiophene) ‘pendants’ of the dendrimer. PHE produced an increase in the voltammetric signals (anodic currents) due to its oxidation on the dendritic material to produce catalytic current, thereby suggesting the suitability of the Au|G3PPT-co-P3HT electrode as a PHE sensor. The electrocatalysis of PHE was made possible by the rigid and planar oligo-P3HT species (formed upon the oxidation of the oligo (thiophene) pendants of the star-copolymer), which allowed the efficient capture (binding) and detection (electrocatalytic oxidation) of PHE molecules. PMID:26404296

  7. Determination of minimum mass and spatial location of initiator for detonation of propylene oxide aerosols

    NASA Astrophysics Data System (ADS)

    Apparao, A.; Saji, J.; Balaji, M.; Devangan, A. K.; Rao, C. R.

    2016-06-01

    The mishandling of liquid fuels during production, processing or transportation can lead to the formation of combustible two-phase mixtures. These mixtures, with the availability of a suitable energy source, may be ignited generating a deflagration, or even a detonation wave. For military applications, unconfined fuel aerosols are created and detonated with the help of a strong shock generated by a powerful energy source. The minimum energy requirement is expressed in terms of the shock strength, or mass of the high-explosive-based initiator. In this study, the detonability of unconfined aerosols of 4.3 kg propylene oxide was studied by positioning different quantities of cylindrical-shaped initiators of RDX/wax (95/5) at a fixed spatial location in the aerosol cloud, and the minimum mass of the initiator required for detonation initiation was determined. The effect of spatial location and the requirement of initiator mass, especially at farther locations where the fuel concentration is likely to be lower and closer to the lower explosive limit, was also investigated. The experimental findings help identify the detonable zone in unconfined propylene oxide aerosol clouds for different combinations of spatial location and mass of initiator.

  8. Quantitative structure-activity relationships for the mutagenicity of propylene oxides with Salmonella.

    PubMed

    Hooberman, B H; Chakraborty, P K; Sinsheimer, J E

    1993-04-01

    A quantitative structure-activity relationship approach was used to investigate the mutagenicity of a series of seventeen-monosubstituted propylene oxides in Salmonella typhimurium strains TA100 and TA1535. Mutagenicity in strain TA100, using a liquid suspension assay, was found to correlate with chemical reactivity, as measured by the rates of reaction with two model bionucleophiles, nicotinamide and 4-(4-nitrobenzyl)pyridine. However, since the reactivity of three of the epoxides did not correlate to their Taft sigma * values, as a measure of the electronic effects of substituent groups, neither was their mutagenicity predicted by this substituent constant. The relative mutagenicity for the propylene oxides was different in the liquid suspension assay than that determined by the standard plate incorporation assay and also differed between the two bacterial strains. The assay differences were attributed to epoxide stability. The differences between strains was observed to be due to the response of the error-prone repair system, found only in TA100, to the stronger alkylating agents. PMID:7680427

  9. Solubility prediction of satranidazole in propylene glycol-water mixtures using extended hildebrand solubility approach.

    PubMed

    Rathi, P B

    2011-11-01

    Extended Hildebrand solubility approach is used to estimate the solubility of satranidazole in binary solvent systems. The solubility of satranidazole in various propylene glycol-water mixtures was analyzed in terms of solute-solvent interactions using a modified version of Hildebrand-Scatchard treatment for regular solutions. The solubility equation employs term interaction energy (W) to replace the geometric mean (δ(1)δ(2)), where δ(1) and δ(2) are the cohesive energy densities for the solvent and solute, respectively. The new equation provides an accurate prediction of solubility once the interaction energy, W, is obtained. In this case, the energy term is regressed against a polynomial in δ(1) of the binary mixture. A quartic expression of W in terms of solvent solubility parameter was found for predicting the solubility of satranidazole in propylene glycol-water mixtures. The expression yields an error in mole fraction solubility of ~3.74%, a value approximating that of the experimentally determined solubility. The method has potential usefulness in preformulation and formulation studies during which solubility prediction is important for drug design. PMID:23112403

  10. Relative toxicities of pure propylene and ethylene glycol and formulated deicers on plant species

    SciTech Connect

    DuFresne, D.L.; Pillard, D.A.

    1994-12-31

    Propylene and ethylene glycol deicers are commonly used at airports in the US and other countries to remove and retard the accumulation of snow and ice on aircraft. Deicers may not only enter water bodies without treatment, due to excessive storm-related flow, but also may expose terrestrial organisms to high concentrations through surface runoff. Most available toxicity data are for aquatic vertebrates and invertebrate species; this study examined effects on terrestrial and aquatic plants. Terrestrial plant species included both a monocot (rye grass, Lolium perenne) and a dicot (lettuce, Lactuca saliva). Aquatic species included a single cell alga (Selenastrum capricomutum), and an aquatic macrophyte (duckweed, Lemna minor). Glycol deicers were obtained in the formulated mixtures used on aircraft. Pure ethylene and propylene glycol were obtained from Sigma{reg_sign}. Parameters measured included germination, root and shoot length, survival, and growth. Formulated deicers, like those used at airports, were generally more toxic than pure chemicals, based on glycol concentration. This greater toxicity of formulated deicers is consistent with results of tests using animal species.

  11. Effects of low temperature on the biodegradation of ethylene glycol and propylene glycol

    SciTech Connect

    Williams, J.B.; Blessing, R.L.

    1995-12-31

    Ethylene glycol and propylene glycol are used in a variety of applications. These compounds are well known to biodegrade readily at 20 C, which is the benchmark temperature for most biodegradation studies. These compounds may enter the environment when the ambient temperatures are significantly below 20 C. Biodegradation data at low temperatures was needed. For example, wintertime airport stormwater discharges contain glycols from deicing fluids. These compounds may enter streams at ambient winter temperatures, or wastewater treatment works which may be operating at temperatures well below 20 C. Biodegradation studies were conducted with BOD bottles incubated at 40 C and 10 C. Biodegradation was slower than 20 C but still significant. For ethylene glycol, the half-life (time at which one-half of the oxygen demand was consumed by the microorganisms) was 5 days at 20 C, 8 days at 10 C, and 25 days at 40 C. For propylene glycol, the half-life was 5 days at 20 C, 12 days at 10 C, and 28 days at 40 C. Two aircraft deicing fluids were also tested, and similar degradation rates were observed. This indicates the presence of additives in deicing fluids has little effect on biodegradation of glycols.

  12. Relative influence of ethanol and propylene glycol cosolvents on deposition of minoxidil into the skin.

    PubMed

    Tata, S; Weiner, N; Flynn, G

    1994-10-01

    Minoxidil, a potent antihypertensive, is moderately effective in the treatment of hair loss when it is applied to the scalp as a 2% solution in 60% ethanol, 20% propylene glycol and 20% water. Important questions remain concerning both the mechanism of delivery and the pathway of penetration of this drug from its ternary solvent system. Since preliminary studies in our laboratory indicated that water in the formulation influenced permeation far less than the other two solvents, we examined the relative deposition and penetration influences of binary combinations of ethanol and propylene glycol. When 50 microL/cm2 of the formulations was spread over hairless mouse skin sections mounted in Franz diffusion cells, only small amounts of minoxidil were actually recovered from the receiver compartments. Nevertheless, more minoxidil penetrated the skin as the proportion of ethanol in the mixtures was increased. To determine if these in vitro results formed a representative picture of the in vivo behaviors of these vehicles, selected deposition experiments were performed on live, anesthetized mice under experimental conditions similar to those used in the diffusion cell work. The good agreement between in vivo and in vitro studies may be a result of the relatively fast partitioning of the drug into the skin as compared to its diffusion through the skin. PMID:7884676

  13. Reactions of Propylene Oxide on Supported Silver Catalysts: Insights into Pathways Limiting Epoxidation Selectivity

    SciTech Connect

    Kulkarni, Apoorva; Bedolla-Pantoja, Marco; Singh, Suyash; Lobo, Raul F.; Mavrikakis, Manos; Barteau, Mark A.

    2012-02-04

    The reactions of propylene oxide (PO) on silver catalysts were studied to understand the network of parallel and sequential reactions that may limit the selectivity of propylene epoxidation by these catalysts. The products of the anaerobic reaction of PO on Ag/a-Al2O3 were propanal, acetone and allyl alcohol for PO conversions below 2–3%. As the conversion of PO was increased either by increasing the temperature or the contact time, acrolein was formed at the expense of propanal, indicating that acrolein is a secondary reaction product in PO decomposition. With addition of oxygen to the feedstream the conversion of PO increased moderately. In contrast to the experiments in absence of oxygen, CO2 was a significant product while the selectivity to propanal decreased as soon as oxygen was introduced in the system. Allyl alcohol disappeared completely from the product stream in the presence of oxygen, reacting to form acrolein and CO2. The product distribution may be explained by a network of reactions involving two types of oxametallacycles formed by ring opening of PO: one with the oxygen bonded to C1 (OMC1, linear) and the other with oxygen bonded to C2 (OMC2, branched). OMC1 reacts to form PO, propanal, and allyl alcohol.

  14. Propylene cross-bridged macrocyclic bifunctional chelator: a new design for facile bioconjugation and robust (64)Cu complex stability.

    PubMed

    Pandya, Darpan N; Bhatt, Nikunj; An, Gwang Il; Ha, Yeong Su; Soni, Nisarg; Lee, Hochun; Lee, Yong Jin; Kim, Jung Young; Lee, Woonghee; Ahn, Heesu; Yoo, Jeongsoo

    2014-09-11

    The first macrocyclic bifunctional chelator incorporating propylene cross-bridge was efficiently synthesized from cyclam in seven steps. After the introduction of an extra functional group for facile conjugation onto the propylene cross-bridge, the two carboxylic acid pendants could contribute to strong coordination of Cu(II) ions, leading to a robust Cu complex. The cyclic RGD peptide conjugate of PCB-TE2A-NCS was prepared and successfully radiolabeled with (64)Cu ion. The radiolabeled peptide conjugate was evaluated in vivo through a biodistribution study and animal PET imaging to demonstrate high tumor uptake with low background. PMID:25137619

  15. Photoemission currents in nitrous-oxide-saturated aqueous solutions of 1,2- and 1,3-propylene glycol

    SciTech Connect

    Kokilashvili, R.G.; Rotenberg, Z.A.

    1986-04-01

    This paper extends the study of photocurrent amplitude and phase measured during modulated illumination of a mercury electrode; the extension of work is to the two homologs of ethylene glycol (EG), 1, 3-propylene glycol (PG-1,3) and 1,2-propylene glycol (PG-1,2). A correlation may be recorded with the physicochemical properties of the corresponding solvents. EG and PG-1,2 are similar in their degrees of structuring and solvating powers, but they differ in these properties from PG-1,3. The reason is to be found in the formation of intramolecular hydrogen bonds between the OH groups in EG and PG-1,2.

  16. Microchip electrospray: cone-jet stability analysis for water-acetonitrile and water-methanol mobile phases.

    PubMed

    Jung, Stephanie; Effelsberg, Uwe; Tallarek, Ulrich

    2011-03-25

    Changes in mobile phase composition during high performance liquid chromatography (HPLC) gradient elution coupled to mass spectrometry (MS) sensitively affect electrospray operation modes. In this work, we identify the influences of dynamic changes in bulk conductivity on the cone-jet stability island for aqueous acetonitrile and aqueous methanol mobile phases commonly used in reversed-phase HPLC. Bulk conductivities of the mobile phases were varied by adding different amounts of formic acid. A commercial microchip-HPLC/ESI-MS configuration was modified to enable in situ electrospray diagnostics by frequency analysis of the microchip emitter current and spray imaging. This approach facilitated the detection of different spray modes together with their onset potentials. The established spray modes are described and the differences in onset potentials and stability regions explained by the physicochemical properties of the electrosprayed liquid. PMID:21333298

  17. Solvation of fluoro-acetonitrile in water by 2D-IR spectroscopy: A combined experimental-computational study

    SciTech Connect

    Cazade, Pierre-André; Das, Akshaya K.; Tran, Halina; Kläsi, Felix; Hamm, Peter; Bereau, Tristan; Meuwly, Markus

    2015-06-07

    The solvent dynamics around fluorinated acetonitrile is characterized by 2-dimensional infrared spectroscopy and atomistic simulations. The lineshape of the linear infrared spectrum is better captured by semiempirical (density functional tight binding) mixed quantum mechanical/molecular mechanics simulations, whereas force field simulations with multipolar interactions yield lineshapes that are significantly too narrow. For the solvent dynamics, a relatively slow time scale of 2 ps is found from the experiments and supported by the mixed quantum mechanical/molecular mechanics simulations. With multipolar force fields fitted to the available thermodynamical data, the time scale is considerably faster—on the 0.5 ps time scale. The simulations provide evidence for a well established CF–HOH hydrogen bond (population of 25%) which is found from the radial distribution function g(r) from both, force field and quantum mechanics/molecular mechanics simulations.

  18. An analytical method for the determination of perfluorinated compounds in whole blood using acetonitrile and solid phase extraction methods.

    PubMed

    Yeung, Leo W Y; Taniyasu, Sachi; Kannan, Kurunthachalam; Xu, Della Z Y; Guruge, Keerthi S; Lam, Paul K S; Yamashita, Nobuyoshi

    2009-06-19

    A method for the analysis of perfluorinated compounds (perfluoroalkyl sulfonates: C4, C6, C8, C10; perfluoroalkyl sulfinates: C6, C8, C10; perfluorooctanesulfonamide, N-ethyl perfluorooctanesulfonamide, N-ethyl perfluorooctanesulfonamidoacetate, perfluorocarboxylates: C4-C14; fluorotelomer carboxylate (7:3, 8:2) in whole blood using acetonitrile and OASIS WAX solid phase extraction (SPE) cartridge was developed. Separation of target compounds in two HPLC columns (ion exchange JJ50-2D and C18 Betasil columns) was examined. Matrix recoveries of the developed methods ranged from 70% to 120%. Separation of possible inferences such as taurodeoxycholic acid (TDC) was accomplished using an ion exchange JJ50-2D column, and this separation was validated using whole blood of different animals. PMID:19439311

  19. Effect of phase symmetry on the NMR spectrum of acetonitrile oriented in a uniaxial-biaxial-uniaxial phase

    NASA Astrophysics Data System (ADS)

    Deepak, H. S. Vinay; Yelamaggad, C. V.; Khetrapal, C. L.; Ramanathan, K. V.

    2016-09-01

    We report here the measurement of the Csbnd H and the Hsbnd H dipolar couplings of the methyl group of acetonitrile oriented in the biaxial liquid crystal potassium laurate/1-decanol/water system. These parameters show large variations when measured as a function of temperature. The variations follow the symmetry of the phase as the liquid crystal goes through the sequence of uniaxial - biaxial - uniaxial phases and show a close correspondence to the phase changes that occur in the liquid crystalline solvent coinciding with the onset of biaxiality. The Hsbnd Csbnd H bond angle calculated after incorporating vibrational corrections to the dipolar couplings is discussed in terms of contributions in the case of the biaxial liquid crystal arising from vibration-rotation interaction effects.

  20. Temperature deactivation of excited Tb{sup 3+} in the presence of 1, 2-dioxetane in acetonitrile

    SciTech Connect

    Ableeva, N.Sh.; Voloshin, A.I.; Ostakhov, S.S.

    1994-10-01

    Quenching the fluorescence (FL) of terbium perchlorate by 2,2{prime}-adamantane-2,2{prime}-dioxide (1) was shown to have a chemical character and was caused by the formation of the [1...Tb{sup 3+}] complex. The dependence of the lifetime ({tau}) of FL of Tb{sup *3+} in acetonitrile on the temperature and concentration of 1 has been studied. The temperature dependence of {tau} is caused by a rearrangement of the inner sphere of the aquasolvate complexes of Tb{sup 3+}, which leads to the replacement of H{sub 2}O with MeCN and 1. The energy of replacing the H{sub 2}O molecule in the inner sphere of complexes with a solvent molecule has been calculated.

  1. Catalytic properties of RhCl[sub 3] [center dot] 3H[sub 2]O immobilized on the modified poly(styrene-divinylbenzene) copolymer in aqueous phase hydroformylation of propylene

    SciTech Connect

    Ro, K.S.; Woo, S.I. )

    1994-02-01

    RhCl[sub 3] [center dot] 3H[sub 2]O and RhCl(CO)(PPh[sub 3])[sub 2] were immobilized on the poly(styrene-divinylbenzene) copolymer (PS/DVB) containing -CH[sub 2]P(C[sub 6]H[sub 4]SO[sub 3]H)[sub 2] (DPPDS: diphenylphosphine disulfonate) groups to give active and stable hydroformylation catalysts in an aqueous phase. Solid-state [sup 31]P NMR spectra and FTIR analysis indicate that the structure of RhCl[sub 3] [center dot] 3H[sub 2]O immobilized on the PS/DVB containing DPPDS groups (Rh(III)/SPPS) is similar to that of RhCl(CO)(PPh[sub 3])[sub 2] immobilized on the same polymer (Rh(I)/SPPS). The hydroformylation of propylene using these catalysts (Rh(III)/SPPS) has been investigated at 373 K and in the pressure range between 5 and 40 atm in an aqueous phase. The rate of hydroformylation was approximately first order with respect to catalyst concentration and increased with the increase of propylene concentration up to 0.45 mol/liter. The rate also increased with the increase of hydrogen pressure. However, the rate of hydroformylation passed through a maximum with the increase of partial pressure of carbon monoxide. The activation energy of propylene hydroformylation catalyzed over Rh(III)/SPPS between 353 and 393 K was found to be 12.1 kcal/mol. Kinetic study with Rh(III)/SPPS containing various amounts of SO[sub 3]H group indicates that SO[sub 3]H groups play an important role in improving the catalytic activity in the aqueous phase hydroformylation. 18 refs., 11 figs., 2 tabs.

  2. Adsorption of water from aqueous acetonitrile on silica-based stationary phases in aqueous normal-phase liquid chromatography.

    PubMed

    Soukup, Jan; Jandera, Pavel

    2014-12-29

    Excess adsorption of water from aqueous acetonitrile mobile phases was investigated on 16 stationary phases using the frontal analysis method and coulometric Karl-Fischer titration. The stationary phases include silica gel and silica-bonded phases with different polarities, octadecyl and cholesterol, phenyl, nitrile, pentafluorophenylpropyl, diol and zwitterionic sulfobetaine and phosphorylcholine ligands bonded on silica, hybrid organic-silica and hydrosilated matrices. Both fully porous and core-shell column types were included. Preferential uptake of water by the columns can be described by Langmuir isotherms. Even though a diffuse rather than a compact adsorbed discrete layer of water on the adsorbent surface can be formed because of the unlimited miscibility of water with acetonitrile, for convenience, the preferentially adsorbed water was expressed in terms of a hypothetical monomolecular water layer equivalent in the inner pores. The uptake of water strongly depends on the polarity and type of the column. Less than one monomolecular water layer equivalent was adsorbed on moderate polar silica hydride-based stationary phases, Ascentis Express F5 and Ascentis Express CN column at the saturation capacity, while on more polar stationary phases, several water layer equivalents were up-taken from the mobile phase. The strongest affinity to water was observed on the ZIC cHILIC stationary phases, where more than nine water layer equivalents were adsorbed onto its surface at its saturation capacity. Columns with bonded hydroxyl and diol ligands show stronger water adsorption in comparison to bare silica. Columns based on hydrosilated silica generally show significantly decreased water uptake in comparison to stationary phases bonded on ordinary silica. Significant correlations were found between the water uptake and the separation selectivity for compounds with strong polarity differences. PMID:25544246

  3. Thermodynamics of various F420 coenzyme models as sources of electrons, hydride ions, hydrogen atoms and protons in acetonitrile.

    PubMed

    Xia, Ke; Shen, Guang-Bin; Zhu, Xiao-Qing

    2015-06-14

    32 F420 coenzyme models with alkylation of the three different N atoms (N1, N3 and N10) in the core structure (XFH(-)) were designed and synthesized and the thermodynamic driving forces (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the 32 XFH(-) releasing hydride ions, hydrogen atoms and electrons, the thermodynamic driving forces of the 32 XFH˙ releasing protons and hydrogen atoms and the thermodynamic driving forces of XF(-)˙ releasing electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The effects of the methyl group at N1, N3 and N10 and a negative charge on N1 and N10 atoms on the six thermodynamic driving forces of the F420 coenzyme models and their related reaction intermediates were examined; the results show that seating arrangements of the methyl group and the negative charge have remarkably different effects on the thermodynamic properties of the F420 coenzyme models and their related reaction intermediates. The effects of the substituents at C7 and C8 on the six thermodynamic driving forces of the F420 coenzyme models and their related reaction intermediates were also examined; the results show that the substituents at C7 and C8 have good Hammett linear free energy relationships with the six thermodynamic parameters. Meanwhile, a reasonable determination of possible reactions between members of the F420 family and NADH family in vivo was given according to a thermodynamic analysis platform constructed using the elementary step thermodynamic parameter of F420 coenzyme model 2FH(-) and NADH model MNAH releasing hydride ions in acetonitrile. The information disclosed in this work can not only fill a gap in the chemical thermodynamics of F420 coenzyme models as a class of very important organic sources of electrons, hydride ions, hydrogen atoms and protons, but also strongly promote the fast development of the chemistry and applications of F420 coenzyme

  4. Studies on the nuances of the electrochemically induced room temperature isomerization of cis-stilbene in acetonitrile and ionic liquids.

    PubMed

    Abdul-Rahim, Omar; Simonov, Alexandr N; Boas, John F; Rüther, Thomas; Collins, David J; Perlmutter, Patrick; Bond, Alan M

    2014-03-20

    Electrochemical reduction of cis-stilbene occurs by two well-resolved one-electron reduction steps in acetonitrile with (n-Bu)4NPF6 as the supporting electrolyte and in N-butyl-N-methylpyrrolidinium (Pyrr1,4(+)) and (trimethylamine)(dimethylethylamine)-dihydroborate bis(trifluoromethylsulfonyl)amide (NTf2(-)) ionic liquids (ILs). Mechanistic details of the electroreduction have been probed by dc and Fourier transformed ac voltammetry, simulation of the voltammetry, bulk electrolysis, and EPR spectroscopy. The first one-electron reduction induces fast cis to trans isomerization in CH3CN and ILs, most likely occurring via disproportionation of cis-stilbene radical anions and fast transformation of the cis-dianion to the trans-configuration. The second reduction process is chemically irreversible in CH3CN due to protonation of the dianion but chemically reversible in highly aprotic ILs under high cis-stilbene concentration conditions. Increase of the (n-Bu)4NPF6 supporting electrolyte concentration (0.01-1.0 M) in CH3CN induces substantial positive shifts in the potentials for reduction of cis-stilbene, consistent with strong ion pairing of the anion radical and dianion with (n-Bu)4N(+). However, protection by ion pairing against protonation of the stilbene dianions or electrochemically induced cis-trans-stilbene isomerization is not achieved. Differences in electrode kinetics and reversible potentials for cis-stilbene(0/•-) and trans-stilbene(0/•-) processes are less pronounced in the Pyrr1,4-NTf2 ionic liquid than in the molecular solvent acetonitrile. PMID:24558952

  5. Capacitive energy storage in nanostructured carbon-electrolyte systems.

    PubMed

    Simon, P; Gogotsi, Y

    2013-05-21

    Securing our energy future is the most important problem that humanity faces in this century. Burning fossil fuels is not sustainable, and wide use of renewable energy sources will require a drastically increased ability to store electrical energy. In the move toward an electrical economy, chemical (batteries) and capacitive energy storage (electrochemical capacitors or supercapacitors) devices are expected to play an important role. This Account summarizes research in the field of electrochemical capacitors conducted over the past decade. Overall, the combination of the right electrode materials with a proper electrolyte can successfully increase both the energy stored by the device and its power, but no perfect active material exists and no electrolyte suits every material and every performance goal. However, today, many materials are available, including porous activated, carbide-derived, and templated carbons with high surface areas and porosities that range from subnanometer to just a few nanometers. If the pore size is matched with the electrolyte ion size, those materials can provide high energy density. Exohedral nanoparticles, such as carbon nanotubes and onion-like carbon, can provide high power due to fast ion sorption/desorption on their outer surfaces. Because of its higher charge-discharge rates compared with activated carbons, graphene has attracted increasing attention, but graphene had not yet shown a higher volumetric capacitance than porous carbons. Although aqueous electrolytes, such as sodium sulfate, are the safest and least expensive, they have a limited voltage window. Organic electrolytes, such as solutions of [N(C2H5)4]BF4 in acetonitrile or propylene carbonate, are the most common in commercial devices. Researchers are increasingly interested in nonflammable ionic liquids. These liquids have low vapor pressures, which allow them to be used safely over a temperature range from -50 °C to at least 100 °C and over a larger voltage window

  6. Acetonitrile and benzene in the breath of smokers and non-smokers investigated by proton transfer reaction mass spectrometry (PTR-MS)

    NASA Astrophysics Data System (ADS)

    Jordan, A.; Hansel, A.; Holzinger, R.; Lindinger, W.

    1995-09-01

    Benzene and acetonitrile are both present in greater concentrations in the breath of smokers than in non-smokers. The concentrations of these neutrals can be readily detected in the gas phase by their proton transfer reactions with H3O+. The concentration of benzene in the breath of smokers rapidly decreases with the time since the last cigarette was smoked, declining to values similar to those of non-smokers within an hour. In contrast, the concentration of acetonitrile in the breath of smokers takes nearly a week to decrease to that of non-somokers, once smoking stops. Thus the analysis of acetonitrile in the breath is a most suitable indicator of whether a given subject is or is not a smoker.

  7. Hirshfeld and DFT analysis of the N-heterocyclic carbene proligand methylenebis(N-butylimidazolium) as the acetonitrile-solvated diiodide salt.

    PubMed

    Cebollada, Andrea; Vellé, Alba; Sanz Miguel, Pablo J

    2016-06-01

    N-Heterocyclic carbene (NHC) based systems are usually exploited in the exploration of catalytic mechanisms and processes in organocatalysis, and homo- and heterogeneous catalysis. However, their molecular structures have not received adequate attention. The NHC proligand methylenebis(N-butylimidazolium) has been synthesized as the acetonitrile solvate of the diiodide salt, C15H26N4(2+)·2I(-)·CH3CN [1,1'-methylenebis(3-butylimidazolium) diiodide acetonitrile monosolvate], and fully characterized. An interesting cation-anion connection pattern has been identified in the crystal lattice, in which three iodide anions interact simultaneously with the cisoid-oriented cation. A Hirshfeld surface analysis reveals the predominance of hydrogen bonding over anion-π interactions. This particular arrangement is observed in different methylene-bridged bis(imidazolium) cations bearing chloride or bromide counter-anions. Density functional theory (DFT) calculations with acetonitrile as solvent reproduce the geometry of the title cation. PMID:27256692

  8. Evaluation of Propylene Glycol-Based Fluids for Constellation Habitats and Vehicles

    NASA Technical Reports Server (NTRS)

    Lee, Steve

    2009-01-01

    Two fluid life tests have been conducted to evaluate propylene glycol-based fluids for use in Constellation habitats and vehicles. The first test was conducted from November 2008 to January 2009 to help determine the compatibility of the propylene glycol-based fluid selected for Orion at the time. When the first test uncovered problems with the fluid selection, an investigation and selection of a new fluid were conducted. A second test was started in March 2010 to evaluate the new selection. For the first test, the fluid was subjected to a thermal fluid loop that had flight-like properties, as compared to Orion. The fluid loop had similar wetted materials, temperatures, flow rates, and aluminum wetted surface area to fluid volume ratio. The test was designed to last for 10 years, the life expectancy of the lunar habitat. However, the test lasted less than two months. System filters became clogged with precipitate, rendering the fluid system inoperable. Upon examination of the precipitate, it was determined that the precipitate composition contained aluminum, which could have only come from materials in the test stand, as aluminum is not part of the original fluid composition. Also, the fluid pH was determined to have increased from 10.1, at the first test sample, to 12.2, at the completion of the test. This high of a pH is corrosive to aluminum and was certainly a contributing factor to the development of precipitate. Due to the problems encountered during this test, the fluid was rejected as a coolant candidate for Orion. A new propylene glycol-based fluid was selected by the Orion project for use in the Orion vehicle. The Orion project has conducted a series of screening tests to help verify that there will be no problems with the new fluid selection. To compliment testing performed by the Orion project team, a new life test was developed to test the new fluid. The new test bed was similar to the original test bed, but with some improvements based on experience

  9. Kinetics and Mechanism of the Reaction of Hydoxyl Radicals with Acetonitrile under Atmospheric Conditions

    NASA Technical Reports Server (NTRS)

    Hynes, A. J.; Wine, P. H.

    1997-01-01

    scheme to extract kinetic information about the adduct reations with O2 and branching ratios for OH regeneration. A plausible mechanism for OH regeneration in (2) involves OH addition to the nitrogen atom followed by O2 addition to the cyano carbon atom, isomeriazation and decomposition to D2CO + DOCN + OH. Our results suggest that the OH + CH3CN reaction occurs via a complex mechanism involving both bimolecular and termolecular pathways, analogous to the mechanisms for the the important atmospheric reactions of OH with CO and HNO3.

  10. A safe and effective propylene glycol based capture liquid for fruit fly (Diptera: Tephritidae) traps baited with synthetic lures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antifreeze is often used as the capture liquid in insect traps for its preservation and evaporation attributes. In tests reported herein, fruit fly traps using non-toxic household propylene glycol based antifreeze captured significantly more Anastrepha ludens than did traps with the automotive anti...

  11. Evaluation of the Effect of Green Tea Extract on Mouth Bacterial Activity in the Presence of Propylene Glycol

    PubMed Central

    Moghbel, Abdolhossein; Farjzadeh, Ahmad; Aghel, Nasrin; Agheli, Homaun; Raisi, Nafiseh

    2012-01-01

    Background Compounds present in green tea have proved to inhibit the growth and activity of bacteria associated with infections. Objectives To assess the effects of green tea leaves extract in presence of propylene glycol on the aerobic mouth bacteria load. Materials and Methods Saliva of 25 volunteer girl students aging 20-25 years were selected and evaluated by a mouthwash sample containing 1% tannin, as the most effective antibacterial complex in green tea. Comparative studies were also conducted between green tea mouthwashes containing 1% tannin and a similar sample with 10% propylene glycol added during extraction. This comparison was applied for a chlorhexidine 0.2% sample as a chemical mouthwash brand, too. Results There was a meaningful difference between the green tea mouthwashes containing 10% propylene glycol and the simple green tea extract (P < 0.05). Significant difference was also seen between the herbal and chemical mouthwashes (P < 0.05). The extract 1% tannin containing 10% propylene glycol reduced the aerobic mouth bacterial load of the student salvia about 64 percent. The pH monotonousness in different days and temperatures approved the stability of tannin in liquid water medium. Conclusions Using green tea extract as a herbal mouthwash is safe and harmless specially for children and pregnant women. This result led us to suppose that green tea may prevent plaque formation on teeth, coming over halitosis due to mouth infection, too. These effects need to be approved in an in vivo trial as a second study. PMID:24624155

  12. A metal-organic framework-based splitter for separating propylene from propane.

    PubMed

    Cadiau, A; Adil, K; Bhatt, P M; Belmabkhout, Y; Eddaoudi, M

    2016-07-01

    The chemical industry is dependent on the olefin/paraffin separation, which is mainly accomplished by using energy-intensive processes. We report the use of reticular chemistry for the fabrication of a chemically stable fluorinated metal-organic framework (MOF) material (NbOFFIVE-1-Ni, also referred to as KAUST-7). The bridging of Ni(II)-pyrazine square-grid layers with (NbOF5)(2-) pillars afforded the construction of a three-dimensional MOF, enclosing a periodic array of fluoride anions in contracted square-shaped channels. The judiciously selected bulkier (NbOF5)(2-) caused the looked-for hindrance of the previously free-rotating pyrazine moieties, delimiting the pore system and dictating the pore aperture size and its maximum opening. The restricted MOF window resulted in the selective molecular exclusion of propane from propylene at atmospheric pressure, as evidenced through multiple cyclic mixed-gas adsorption and calorimetric studies. PMID:27387945

  13. First results from electron-photon damage equivalence studies on a generic ethylene-propylene rubber

    SciTech Connect

    Buckalew, W.H.

    1986-04-01

    As part of a simulator adequacy assessment program, the relative effectiveness of electrons and photons to produce damage in a generic ethylene propylene rubber (EPR) has been investigated. The investigation was limited in extent in that a single EPR material, in three thickness, was exposed to Cobalt-60 photons and three electron beam energies. Basing material damage on changes in the EPR mechanical properties elongation and tensile strength, we observed that EPR damage was a smoothly varying function of absorbed energy and independent of irradiating particle type. EPR damage tracked equally well as a function of both incident particle energy and material front surface dose. Based on these preliminary data, we tentatively concluded that a correlation between particle, particle energy, and material damage (as measured by changes in material elongation and/or tensile strength) has been demonstrated. 14 figs.

  14. Compensated Arrhenius formalism applied to a conductivity study in poly(propylene glycol) diacrylate monomers

    NASA Astrophysics Data System (ADS)

    Dubois, F.; Derouiche, Y.; Leblond, J. M.; Maschke, U.; Douali, R.

    2015-09-01

    The temperature dependence of the ionic conductivity is studied in a series of poly(propylene glycol) diacrylate monomers. The experimental data are analyzed by means of the approach recently proposed by Petrowsky et al. [J. Phys. Chem. B. 113, 5996 (2009), 10.1021/jp810095g]. This so-called compensated Arrhenius formalism (CAF) approach takes into account the influence of the dielectric permittivity on the exponential prefactor in the classical Arrhenius equation. The experimental data presented in this paper show a good agreement with the CAF; this means that the exponential prefactor is principally dielectric permittivity dependent. The compensated data revealed two conduction processes with different activation energies; they correspond to low and high temperature ranges, respectively.

  15. Study on quality control of sulfated polysaccharide drug, propylene glycol alginate sodium sulfate (PSS).

    PubMed

    Xue, Yi-Ting; Ren, Li; Li, Shuang; Wang, Lin-Lin; He, Xiao-Xi; Zhao, Xia; Yu, Guang-Li; Guan, Hua-Shi; Li, Chun-Xia

    2016-06-25

    The combination of biological and chemical analysis methods was developed to improve quality control of propylene glycol alginate sodium sulfate (PSS), a sulfated polysaccharide drug. The allergic and anticoagulant assays revealed that PSS fractions with higher Mw and lower M/G ratio may have allergic response and bleeding risks. HPLC with pre-column derivatization, HPGPC and IC methods were combined to analyze 10 batches of PSS samples from different manufacturers. The results showed that the quality of these PSSs varied greatly which in turn led to the unstable anticoagulant activity and side effects. The study indicated that PSS with high purity, M/G ratio above 1.5, Mw of ∼9kD and DS of 9.0-13.0% can ensure clinical efficacy and low incidence of adverse drug reactions. In conclusion, the combined methods would be in favor of guiding manufacture and quality control of PSS to guarantee its effectiveness and safety. PMID:27083824

  16. Reinforced poly(propylene oxide): a very soft and extensible dielectric electroactive polymer

    NASA Astrophysics Data System (ADS)

    Goswami, K.; Galantini, F.; Mazurek, P.; Daugaard, A. E.; Gallone, G.; Skov, A. L.

    2013-11-01

    Poly(propylene oxide) (PPO), a novel soft elastomeric material, and its composites were investigated as a new dielectric electroactive polymer (EAP). The PPO networks were obtained from thiol-ene chemistry by photochemical crosslinking of α,ω-diallyl PPO with a tetra-functional thiol. The elastomer was reinforced with hexamethylenedisilazane treated fumed silica to improve the mechanical properties of PPO. The mechanical properties of PPO and composites thereof were investigated by shear rheology and stress-strain measurements. It was found that incorporation of silica particles improved the stability of the otherwise mechanically weak pure PPO network. Dielectric spectroscopy revealed high relative dielectric permittivity of PPO at 103 Hz of 5.6. The relative permittivity was decreased slightly upon addition of fillers, but remained higher than the commonly used acrylic EAP material VHB4910. The electromechanical actuation performance of both PPO and its composites showed properties as good as VHB4910 and a lower viscous loss.

  17. Ru-Containing Magnetically Recoverable Catalysts: A Sustainable Pathway from Cellulose to Ethylene and Propylene Glycols.

    PubMed

    Manaenkov, Oleg V; Mann, Joshua J; Kislitza, Olga V; Losovyj, Yaroslav; Stein, Barry D; Morgan, David Gene; Pink, Maren; Lependina, Olga L; Shifrina, Zinaida B; Matveeva, Valentina G; Sulman, Esther M; Bronstein, Lyudmila M

    2016-08-24

    Biomass processing to value-added chemicals and biofuels received considerable attention due to the renewable nature of the precursors. Here, we report the development of Ru-containing magnetically recoverable catalysts for cellulose hydrogenolysis to low alcohols, ethylene glycol (EG) and propylene glycol (PG). The catalysts are synthesized by incorporation of magnetite nanoparticles (NPs) in mesoporous silica pores followed by formation of 2 nm Ru NPs. The latter are obtained by thermal decomposition of ruthenium acetylacetonate in the pores. The catalysts showed excellent activities and selectivities at 100% cellulose conversion, exceeding those for the commercial Ru/C. High selectivities as well as activities are attributed to the influence of Fe3O4 on the Ru(0)/Ru(4+) NPs. A facile synthetic protocol, easy magnetic separation, and stability of the catalyst performance after magnetic recovery make these catalysts promising for industrial applications. PMID:27484222

  18. Roles of Poly(propylene Glycol) During Solvent-Based Lamination of Ceramic Green Tapes

    NASA Technical Reports Server (NTRS)

    Suppakarn, Nitinat; Ishida, Hatsuo; Cawley, James D.; Levine, Stanley R. (Technical Monitor)

    2000-01-01

    Solvent lamination for alumina green tapes is readily accomplished using a mixture of ethanol, toluene and poly(propylene glycol). After lamination, the PPG is clearly present as a discrete film at the interface between the laminated tapes. This condition, however, does not generate delamination during firing. Systematic sets of experiments are undertaken to determine the role of PPG in the lamination process and, specifically, the mechanism by which it is redistributed during subsequent processing. PPG slowly diffuses through the organic binder film at room temperature. The PPG diffusion rapidly increases as temperature is increased to 80 C. The key to the efficiency of adhesives during green-tape lamination is mutual solubility of the nonvolatile component of the glue and the base polymeric binder.

  19. Vacuum ultraviolet radiation/atomic oxygen synergism in fluorinated ethylene propylene Teflon erosion

    NASA Technical Reports Server (NTRS)

    Stiegman, A. E.; Brinza, David E.; Laue, Eric G.; Anderson, Mark S.; Liang, Ranty H.

    1992-01-01

    A micrographic investigation is reported of samples of the fluorinated ethylene propylene (FEP) Teflon thermal-blanketing materials recovered from the Long-Duration Exposure Facility (LDEF) satellite. The samples are taken from the trailing edge and row 8 which correspond to exposures to vacuum UV (VUV) and VUV + atomic O, respectively. Data are taken from SEM and IR-spectra observations, and the LDEF leading-edge FEP shows a high degree of erosion, roughening, and sharp peaks angled in the direction of the flow of atomic O. The trailing edge sample influenced primarily by VUV shows a hard brittle layer and some cracked mosaic patterns. Comparisons to a reference sample suggest that the brittle layer is related to exposure to VUV and is removed by atomic-O impingement. Polymers that are stable to VUV radiation appear to be more stable in terms of atomic oxygen.

  20. Penetration of minoxidil from ethanol/propylene glycol solutions: effect of application volume and occlusion.

    PubMed

    Tata, S; Flynn, G L; Weiner, N D

    1995-06-01

    We have previously established that the relative concentrations of propylene glycol and ethanol as a binary solvent system have a significant effect on the skin penetration of 2% solutions of minoxidil at 50 microL/cm2. The present work extends these studies and investigates the penetration of minoxidil from the different vehicle combinations as functions of application volume and occlusion. Decreasing the application volume has a variable effect which depends on vehicle composition. Penetration of minoxidil from 100% ethanol solutions decreased linearly with application volume. Generally, irrespective of the volume applied, the penetration of minoxidil increased with increasing ethanol fraction with a maximum penetration at 90% ethanol. Penetration from all the formulations was enhanced upon occluding the skin, with greatest increase evident in solutions with higher volatile fraction. Penetration of minoxidil in vivo showed trends similar to those seen in vitro. PMID:7562405

  1. Rheological properties and thermal conductivity of AlN-poly(propylene glycol) suspensions

    NASA Astrophysics Data System (ADS)

    Wozniak, Maciej; Rutkowski, Pawel; Kata, Dariusz

    2016-01-01

    Nanofluids have recently attracted researches' attention as a new generation of heat-transferring fluids used in heat exchangers and for energy storage. Also aluminium nitride is commonly known for its considerable heat conductivity, as high as 320 W/(m K). Because of that, the compound might be a preferable dispersed phase of heat-transferring fluids. This presented studies are focused on nano-AlN-poly(propylene glycol) dispersions which can be applied as potential cooling fluids. The rheological response of the suspensions on shearing and their thermal conductivity in the function of solids concentration and temperature were measured and discussed. The most desired result of the studies is to produce dispersions with Newtonian-like flow at increased temperature and at higher shear rate. All the aforementioned parameters conjugated with significant thermal conductivity of such nanofluids could predispose them to be used as effective cooling media.

  2. Compensated Arrhenius formalism applied to a conductivity study in poly(propylene glycol) diacrylate monomers.

    PubMed

    Dubois, F; Derouiche, Y; Leblond, J M; Maschke, U; Douali, R

    2015-09-01

    The temperature dependence of the ionic conductivity is studied in a series of poly(propylene glycol) diacrylate monomers. The experimental data are analyzed by means of the approach recently proposed by Petrowsky et al. [J. Phys. Chem. B. 113, 5996 (2009)10.1021/jp810095g]. This so-called compensated Arrhenius formalism (CAF) approach takes into account the influence of the dielectric permittivity on the exponential prefactor in the classical Arrhenius equation. The experimental data presented in this paper show a good agreement with the CAF; this means that the exponential prefactor is principally dielectric permittivity dependent. The compensated data revealed two conduction processes with different activation energies; they correspond to low and high temperature ranges, respectively. PMID:26465489

  3. Superheated-steam test of ethylene propylene rubber cables using a simultaneous aging and accident environment

    SciTech Connect

    Bennett, P.R.; St. Clair, S.D.; Gilmore, T.W.

    1986-06-01

    The superheated-steam test exposed different ethylene propylene rubber (EPR) cables and insulation specimens to simultaneous aging and a 21-day simultaneous accident environment. In addition, some insulation specimens were exposed to five different aging conditions prior to the 21-day simultaneous accident simulation. The purpose of this superheated-steam test (a follow-on to the saturated-steam tests (NUREG/CR-3538)) was to: (1) examine electrical degradation of different configurations of EPR cables; (2) investigate differences between using superheated-steam or saturated-steam at the start of an accident simulation; (3) determine whether the aging technique used in the saturated-steam test induced artificial degradation; and (4) identify the constituents in EPR that affect moisture absorption.

  4. Raman study of ethylene-propylene copolymers and polyethylene-polypropylene reactor blends

    NASA Astrophysics Data System (ADS)

    Shemouratov, Yu. V.; Prokhorov, K. A.; Nikolaeva, G. Yu.; Pashinin, P. P.; Kovalchuk, A. A.; Klyamkina, A. N.; Nedorezova, P. M.; Demidenok, K. V.; Lebedev, Yu. A.; Antipov, E. M.

    2008-05-01

    The Raman spectra of the ethylene-propylene copolymers (EPC) synthesized using new metallocene catalytic systems and the polypropylene/polyethylene/diblockcopolymer of propylene and ethylene (PP/PE/DBC) blends obtained using the sequential polymerization are studied. The copolymer and reactor blend spectra are analyzed using the Raman spectra of a series of liquid n-alkanes. Significant monotonic changes are observed in the spectra of EPC and the PP/PE/DBC blends when the ethylene content increases. Substantial differences between the series of samples of blends and copolymers are revealed. In contrast to the EPC spectra, the spectra of the PP/PE/DBC reactor blends are represented as an exact superposition of the homopolymer spectra with the weight coefficients proportional to the contents of the blend components. A monotonic blue shift of the line that corresponds to the symmetric stretching mode of the CH2 groups is observed in the EPC Raman spectra when the ethylene content increases. It is demonstrated that, for this line, the peak position only depends on the relative content of comonomers and does not depend on the contents of the PP and PE crystalline phases. The intensity ratio of two fundamental vibrations of PE and PP with frequencies of 1295 and 1330 cm-1 can be used to determine the relative contents of the PE molecules in the trans-conformation and PP macromolecules in the helical conformation in the PP/PE blends. It is demonstrated that variations in the Raman spectra of n-alkanes, EPC, and PP/PE/DBC reactor blends related to variations in the relative contents of various chemical groups are reliably traced in the spectra of all of the materials under study.

  5. Modeling microbial degradation of propylene glycol: electron acceptors and their related redox conditions

    NASA Astrophysics Data System (ADS)

    Dathe, Annette; Fernandez, Perrine M.; Bloem, Esther; Meeussen, Johannes C. L.; French, Helen K.

    2014-05-01

    De-icing chemicals are applied in large amounts at airports during winter conditions to keep the runways and aircrafts ice-free. The commonly used propylene glycol (PG) is easily degradable by local microbial communities, but anoxic zones develop and soluble Fe+2 and Mn+2 ions can reach the groundwater. To enhance microbial induced remediation and reduce the release of iron and manganese, it was proposed to add NO3- together with PG. However, experiments conducted in the unsaturated zone at Gardermoen airport, Norway, revealed that manganese and iron were preferred over NO3- as electron acceptor [1]. The objectives of this study are to quantify mechanisms which control the order of reduction processes in an unsaturated sandy soil, and to test whether measured redox potentials can help to determine underlying biogeochemical reactions. We are modelling the microbial degradation of PG using Monod kinetics described for the chemical equilibrium tool ORCHESTRA [2], following an approach of [1]. The model is calibrated against gas measurements of CO2, NO2 and N2 released from batch experiments performed under controlled conditions. Fe+2 and Mn+2 were measured for the start and end of the experiment, as well as bulk resistivity, pH and electrical conductivity. With the calibrated model we are working towards a tool to quantify microbial induced redox reactions under different soil water saturations to account for seasonal water fluxes especially during snowmelt. [1] Schotanus, D., Meeussen, J.C.L., Lissner, H., van der Ploeg, M.J., Wehrer, M., Totsche, K.U., van der Zee, S.E.A.T.M., 2013. Transport and degradation of propylene glycol in the vadose zone: model development and sensitivity analysis. Environ Sci Pollut Res Int. [2] Meeussen, J.C.L., 2003. ORCHESTRA: An Object-Oriented Framework for Implementing Chemical Equilibrium Models. Environ. Sci. Technol. 37, 1175-1182.

  6. Evaluation of thermal- and photo-crosslinked biodegradable poly(propylene fumarate)-based networks.

    PubMed

    Timmer, Mark D; Ambrose, Catherine G; Mikos, Antonios G

    2003-09-15

    Biodegradable networks of poly(propylene fumarate) (PPF) and the crosslinking reagent poly(propylene fumarate)-diacrylate (PPF-DA) were prepared with thermal- and photo-initiator systems. Thermal-crosslinking was performed with benzoyl peroxide (BP), which is accelerated by N,N-dimethyl-p-toluidine (DMT) and enables injection and in situ polymerization. Photo-crosslinking was accomplished with bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide (BAPO), which is activated by long-wavelength UV light and facilitates material processing with rapid manufacturing techniques, such as stereolithography. Networks were evaluated to assess the effects of the initiators and the PPF/PPF-DA double bond ratio on the mechanical properties. Regardless of the initiator system, the compressive properties of the PPF/PPF-DA networks increased as the double bond ratio decreased from 2 to 0.5. BAPO/UV-initiated networks were significantly stronger than those formed with BP/DMT. The compressive modulus of the photo- and thermal-crosslinked PPF/PPF-DA networks ranged from 310 +/- 25 to 1270 +/- 286 MPa and 75 +/- 8 to 332 +/- 89 MPa, respectively. The corresponding fracture strengths varied from 58 +/- 7 to 129 +/- 17 MPa and 31 +/- 13 to 105 +/- 12 MPa. The mechanical properties were not affected by the initiator concentration. Characterization of the network structures indicated that BAPO was a more efficient initiator for the crosslinking of PPF/PPF-DA, achieving a higher double bond conversion and crosslinking density than its BP counterpart. Estimated average molecular weights between crosslinks (Mc) confirmed the effects of the initiators and PPF/PPF-DA double bond ratio on the mechanical properties. This work demonstrates the capability to control the properties of PPF/PPF-DA networks as well as their versatility to be used as an injectable material or a prefabricated implant. PMID:12926033

  7. Banking of non-viable skin allografts using high concentrations of glycerol or propylene glycol.

    PubMed

    Huang, Qizhi; Pegg, David E; Kearney, John N

    2004-01-01

    The aims of this study were to investigate the kinetics of the current glycerol banking method for the preservation of non-viable skin allografts; to improve it with respect to efficiency and microbial safety; and to investigate the possibility of using propylene glycol in place of glycerol to provide a more rapid process. Skin grafts were preserved in 98% v/v glycerol (GLY) according to the method used in the Sheffield Skin Bank. During the addition and removal processes, the amounts of GLY and water in the skin were determined using the Karl Fischer method and HPLC respectively. Propylene glycol (PG) was investigated as an alternative to glycerol with the object of shortening the process. To avoid the need for prolonged storage in glycerol to disinfect the tissue, and to improve the effectiveness of disinfection, exposure to peracetic acid (PAA) was included and its influence on the kinetics of the preservation process was evaluated. The histological and ultrastructural appearances of skin that had been banked by these methods was also investigated. It was found that the permeation of GLY in skin probably involves two processes: diffusion and binding; the rate of transport was attenuated as the GLY concentration in the skin increased. The current incubation time could be shortened, but an inconveniently prolonged washout process was required. The substitution of PG for GLY accelerated the whole process, particularly the removal process, making the method more convenient for the emergency use of skin grafts in the clinic. The penetration of PG also involved diffusion and binding, but there was no attenuation of transport as the concentration increased. The addition of PAA sterilisation did not alter the transport of GLY or PG. Structural integrity was also maintained with the new banking treatments. An improved banking method can now be proposed; it can be completed in only one working day and the risk of disease transmission is reduced. PMID:15256836

  8. Spectrophotometric study on the proton transfer reaction between 2-amino-4-methylpyridine with 2,6-dichloro-4-nitrophenol in methanol, acetonitrile and the binary mixture 50% methanol+50% acetonitrile.

    PubMed

    Al-Ahmary, Khairia M; Habeeb, Moustafa M; Al-Obidan, Areej H

    2016-02-01

    Proton transfer reaction between 2-amino-4-methylpyridine (2AMP) as the proton acceptor with 2,6-dichloro-4-nitrophenol (DCNP) as the proton donor has been investigated spectrophotometrically in methanol (MeOH), acetonitrile (AN) and a binary mixture composed of 50% MeOH and 50% AN (AN-Me). The composition of the complex has been investigated utilizing Job(')s and photometric titration methods to be 1:1. Minimum-maximum absorbance equation has been applied to estimate the formation constant of the proton transfer reaction (K(PT)) where it reached high values in the investigated solvent confirming its high stability. The formation constant recorded higher value in AN compared with MeOH and mixture of AN-Me. Based on the formation of stable proton transfer complex, a sensitive spectrophotometric method was suggested for quantitative determination of 2AMP. The Lambert-Beer(')s law was obeyed in the concentration range 0.5-8 μg mL(-1) with small values of limits of detection and quantification. The solid complex between 2AMP with DCNP has been synthesized and characterized by elemental analysis to be 1:1 in concordant with the molecular stoichiometry in solution. Further analysis of the solid complex was carried out using infrared and (1)H NMR spectroscopy. PMID:26520474

  9. The Multifunctional Enzyme CYP71B15 (PHYTOALEXIN DEFICIENT3) Converts Cysteine-Indole-3-Acetonitrile to Camalexin in the Indole-3-Acetonitrile Metabolic Network of Arabidopsis thaliana[W][OA

    PubMed Central

    Böttcher, Christoph; Westphal, Lore; Schmotz, Constanze; Prade, Elke; Scheel, Dierk; Glawischnig, Erich

    2009-01-01

    Accumulation of camalexin, the characteristic phytoalexin of Arabidopsis thaliana, is induced by a great variety of plant pathogens. It is derived from Trp, which is converted to indole-3-acetonitrile (IAN) by successive action of the cytochrome P450 enzymes CYP79B2/B3 and CYP71A13. Extracts from wild-type plants and camalexin biosynthetic mutants, treated with silver nitrate or inoculated with Phytophthora infestans, were comprehensively analyzed by ultra-performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry. This metabolomics approach was combined with precursor feeding experiments to characterize the IAN metabolic network and to identify novel biosynthetic intermediates and metabolites of camalexin. Indole-3-carbaldehyde and indole-3-carboxylic acid derivatives were shown to originate from IAN. IAN conjugates with glutathione, γ-glutamylcysteine, and cysteine [Cys(IAN)] accumulated in challenged phytoalexin deficient3 (pad3) mutants. Cys(IAN) rescued the camalexin-deficient phenotype of cyp79b2 cyp79b3 and was itself converted to dihydrocamalexic acid (DHCA), the known substrate of CYP71B15 (PAD3), by microsomes isolated from silver nitrate–treated Arabidopsis leaves. Surprisingly, yeast-expressed CYP71B15 also catalyzed thiazoline ring closure, DHCA formation, and cyanide release with Cys(IAN) as substrate. In conclusion, in the camalexin biosynthetic pathway, IAN is derivatized to the intermediate Cys(IAN), which serves as substrate of the multifunctional cytochrome P450 enzyme CYP71B15. PMID:19567706

  10. Spectrophotometric study on the proton transfer reaction between 2-amino-4-methylpyridine with 2,6-dichloro-4-nitrophenol in methanol, acetonitrile and the binary mixture 50% methanol + 50% acetonitrile

    NASA Astrophysics Data System (ADS)

    Al-Ahmary, Khairia M.; Habeeb, Moustafa M.; Al-Obidan, Areej H.

    2016-02-01

    Proton transfer reaction between 2-amino-4-methylpyridine (2AMP) as the proton acceptor with 2,6-dichloro-4-nitrophenol (DCNP) as the proton donor has been investigated spectrophotometrically in methanol (MeOH), acetonitrile (AN) and a binary mixture composed of 50% MeOH and 50% AN (AN-Me). The composition of the complex has been investigated utilizing Job's and photometric titration methods to be 1:1. Minimum-maximum absorbance equation has been applied to estimate the formation constant of the proton transfer reaction (KPT) where it reached high values in the investigated solvent confirming its high stability. The formation constant recorded higher value in AN compared with MeOH and mixture of AN-Me. Based on the formation of stable proton transfer complex, a sensitive spectrophotometric method was suggested for quantitative determination of 2AMP. The Lambert-Beer's law was obeyed in the concentration range 0.5-8 μg mL- 1 with small values of limits of detection and quantification. The solid complex between 2AMP with DCNP has been synthesized and characterized by elemental analysis to be 1:1 in concordant with the molecular stoichiometry in solution. Further analysis of the solid complex was carried out using infrared and 1H NMR spectroscopy.

  11. Analysis of Triacylglycerol and Fatty Acid Isomers by Low-Temperature Silver-Ion High Performance Liquid Chromatography with Acetonitrile in Hexane as Solvent: Limitations of the Methodology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silver ion HPLC (Ag HPLC), utilizing columns containing silver ions bonded to a silica substrate and acetonitrile in hexane as solvent, has proven to be a powerful technology for the analysis of geometric (cis or trans) or positional fatty acids, fatty acid ester (primarily methyl ester; FAME), or t...

  12. The role of low levels of water in the electrochemical oxidation of α-tocopherol (vitamin E) and other phenols in acetonitrile.

    PubMed

    Tan, Ying Shan; Chen, Shanshan; Hong, Wan Mei; Kan, Jia Min; Kwek, Edwin Swee Hee; Lim, Shi Yu; Lim, Zhen Hui; Tessensohn, Malcolm E; Zhang, Yinlu; Webster, Richard D

    2011-07-28

    The phenol, α-tocopherol, can be electrochemically oxidised in a -2e(-)/-H(+) process to form a diamagnetic cation that is long-lived in dry organic solvents such as acetonitrile and dichloromethane, but in the presence of water quickly reacts to form a hemiketal. Variable scan rate cyclic voltammetry experiments in acetonitrile with carefully controlled amounts of water between 0.010 M-0.6 M were performed in order to determine the rate of reaction of the diamagnetic cation with water. The water content of the solvent was accurately determined by Karl Fischer coulometric titrations and the voltammetric data were modelled using digital simulation techniques. The oxidation peak potential of α-tocopherol measured during cyclic voltammetry experiments was found to shift to less positive potentials as increasing amounts of water (0.01-0.6 M) were added to the acetonitrile, which was interpreted based on hydrogen-bonding interactions between the phenolic hydrogen atom and water. Several other phenols were examined and they displayed similar voltammetric features to α-tocopherol, suggesting that interactions of phenols with trace amounts of water were a common occurrence in acetonitrile. The H-bonding interactions of α-tocopherol with water were also examined via NMR and UV-vis spectroscopies, with the voltammetric and spectroscopic studies extended to include other coordinating solvents (dimethyl sulfoxide and pyridine). PMID:21670827

  13. Chain structure, aggregation state structure, and tensile behavior of segmented ethylene-propylene copolymers produced by an oscillating unbridged metallocene catalyst.

    PubMed

    Tong, Zai-Zai; Huang, Yao; Xu, Jun-Ting; Fu, Zhi-Sheng; Fan, Zhi-Qiang

    2015-05-14

    Segmented ethylene-propylene copolymers (SEPs) with different propylene contents were prepared by an unbridged metallocene bis(2,4,6-trimethylindenyl)zirconium dichloride [(2,4,6-Me3Ind)2ZrCl2] catalyst. Due to oscillation of the unbridged ligands in the catalyst, the SEPs are composed of segments with low propylene contents, alternated by the segments with high propylene contents. Such a chain structure was verified by (13)C NMR and successive self-nucleation and annealing (SSA). As the propylene/ethylene feed ratio during copolymerization increases, the comonomer contents in both segments are increased, leading to noncrystallizability of the high propylene segments and smaller crystallinity of the low propylene segments. Consequently, SEPs may be used as thermoplastic elastomers (TPEs). The aggregation state structures at nano- and micro-scales were characterized with small angle X-ray scattering, transmission electron microscopy and polarized optical microscopy, and compared with those of ethylene-octene multiblocky copolymers (OBCs) with similar crystallinity. It is found that SEPs form thinner lamellar crystals with a lower melting temperature due to shorter length and higher comonomer content of the low propylene segments. Moreover, the short length of the high propylene segments in SEPs results in an evidently thinner amorphous layer among the lamellar crystals, thus lots of amorphous phases are excluded out of the interlamellae. Accordingly, ill-developed spherulites or even bundle crystals are formed in SEPs, as compared with the well-developed spherulites in OBCs. SEPs exhibit the tensile property of typical TPEs with diffused yielding and large strain at break. PMID:25905557

  14. Catalytic Hydrogenolysis of 5-Carbon Sugar Alcohols

    SciTech Connect

    Zacher, Alan H.; Frye, John G.; Werpy, Todd A.; Miller, Dennis J.

    2005-01-01

    PNNL, in cooperation with the USDOE and CRADA partners, National Corn Growers Association and Archer Daniels Midland, has developed a new class of catalysts based on Nickel and Rhenium with very effective performance for highly selective, high conversion hydrogenolysis of five–carbon sugar alcohols to useful glycols. The Ni-Re catalyst appears to exhibit preferential hydrogenolysis of the carbon-carbon bonds of secondary carbons over primary carbons of the 5-carbon sugar alcohols tested. In addition, the catalyst has demonstrated significant and unique primary C-O bond hydrogenolysis activity in its ability to convert glycerol into 1,2- propylene glycol, which is then stable in the presence of this class of catalysts. The rhenium containing catalysts are found to have higher activity and better selectivity to desired glycols than previously reported catalysts. A continuous flow reactor lifetime test of over 1500 hours also demonstrated the requisite high stability for an industrially attractive process.

  15. Thionations using a P4S10-pyridine complex in solvents such as acetonitrile and dimethyl sulfone.

    PubMed

    Bergman, Jan; Pettersson, Birgitta; Hasimbegovic, Vedran; Svensson, Per H

    2011-03-18

    Tetraphosphorus decasulfide (P(4)S(10)) in pyridine has been used as a thionating agent for a long period of time. The moisture-sensitive reagent has now been isolated in crystalline form, and the detailed structure has been determined by X-ray crystallography. The thionating power of this storable reagent has been studied and transferred to solvents such as acetonitrile in which it has proven to be synthetically useful and exceptionally selective. Its properties have been compared with the so-called Lawesson reagent (LR). Particularly interesting are the results from thionations at relatively high temperatures (∼165 °C) in dimethyl sulfone as solvent. Under these conditions, for instance, acridone and 3-acetylindole could quickly be transformed to the corresponding thionated derivatives. Glycylglycine similarly gave piperazinedithione. At these temperatures, LR is inefficient due to rapid decomposition. The thionated products are generally cleaner and more easy to obtain because in the crystalline reagent, impurities which invariably are present in the conventional reagents, P(4)S(10) in pyridine or LR, have been removed. PMID:21341727

  16. Vibrational spectroscopic characterization of stable solvates in the LiClO 4/formamide:acetonitrile system

    NASA Astrophysics Data System (ADS)

    Alves, Wagner A.

    2007-03-01

    Raman and infrared (IR) experiments of extremely high concentrated solutions (1.0-5.0 M) of lithium perchlorate in equimolar formamide (FA) and acetonitrile (ACN) mixture were carried out. Raman quantitative analyses performed in the C dbnd O and C tbnd N bands of FA and ACN, respectively, the appearance of a new IR band in the N-H stretching region and the presence of the band at 939 cm -1 were interpreted in terms of a solvent separated ion pairs model. In salt concentrations higher than 3.0 M, a weak band at 945 cm -1 (contact ion pairs) can also be seen. Indeed, the mixture of solvents with considerable differences in the acid-base characters allows to prepare electrolytic solutions where the contact ion pairs formation is low. A coordination number of 4 for the lithium cation is suggested and this value is in full agreement with other authors. Fundamental aspects and the importance of the present system for the development of new lithium-based rechargeable batteries are also discussed.

  17. Rate theory of solvent exchange and kinetics of Li(+) - BF4 (-)/PF6 (-) ion pairs in acetonitrile.

    PubMed

    Dang, Liem X; Chang, Tsun-Mei

    2016-09-01

    In this paper, we describe our efforts to apply rate theories in studies of solvent exchange around Li(+) and the kinetics of ion pairings in lithium-ion batteries (LIBs). We report one of the first computer simulations of the exchange dynamics around solvated Li(+) in acetonitrile (ACN), which is a common solvent used in LIBs. We also provide details of the ion-pairing kinetics of Li(+)-[BF4] and Li(+)-[PF6] in ACN. Using our polarizable force-field models and employing classical rate theories of chemical reactions, we examine the ACN exchange process between the first and second solvation shells around Li(+). We calculate exchange rates using transition state theory and weighted them with the transmission coefficients determined by the reactive flux, Impey, Madden, and McDonald approaches, and Grote-Hynes theory. We found the relaxation times changed from 180 ps to 4600 ps and from 30 ps to 280 ps for Li(+)-[BF4] and Li(+)-[PF6] ion pairs, respectively. These results confirm that the solvent response to the kinetics of ion pairing is significant. Our results also show that, in addition to affecting the free energy of solvation into ACN, the anion type also should significantly influence the kinetics of ion pairing. These results will increase our understanding of the thermodynamic and kinetic properties of LIB systems. PMID:27608999

  18. Thermodynamic and transport properties of spiro-(1,1')-bipyrrolidinium tetrafluoroborate and acetonitrile mixtures: A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Qing-Yin, Zhang; Peng, Xie; Xin, Wang; Xue-Wen, Yu; Zhi-Qiang, Shi; Shi-Huai, Zhao

    2016-06-01

    Organic salts such as spiro-(1,1')-bipyrrolidinium tetrafluoroborate ([SBP][BF4]) dissolved in liquid acetonitrile (ACN) are a new kind of organic salt solution, which is expected to be used as an electrolyte in electrical double layer capacitors (EDLCs). To explore the physicochemical properties of the solution, an all-atom force field is established on the basis of AMBER parameter values and quantum mechanical calculations. Molecular dynamics (MD) simulations are carried out to explore the liquid structure and physicochemical properties of [SBP][BF4] electrolyte at room temperature. The computed thermodynamic and transport properties match the available experimental results very well. The microscopic structures of [SBP][BF4] salt solution are also discussed in detail. The method used in this work provides an efficient way of predicting the properties of organic salt solvent as an electrolyte in EDLCs. Project supported by the National Natural Science Foundation of China (Grant Nos. 21476172 and 51172160), the National High Technology Research and Development Program of China (Grant No. 2013AA050905), and the Natural Science Foundation of Tianjin, China (Grant Nos. 12JCZDJC28400, 14RCHZGX00859, 14JCTPJC00484, and 14JCQNJC07200).

  19. A new insight into the photochemistry of avobenzone in gas phase and acetonitrile from ab initio calculations.

    PubMed

    Kojić, Marko; Petković, Milena; Etinski, Mihajlo

    2016-08-10

    Avobenzone (4-tert-butyl-4'-methoxydibenzoylmethane, AB) is one of the most widely used filters in sunscreens for skin photoprotection in the UVA band. The photochemistry of AB includes keto-enol tautomerization, cis-trans isomerization, rotation about the single bond and α bond cleavages of carbonyl groups. In this contribution we study chelated and non-chelated enol, rotamers Z and E, and keto tautomers of AB in the ground and excited states in gas phase and acetonitrile by means of a coupled cluster method. Our findings suggest that torsion around the double C2-C3 bond of photoexcited chelated enol leads to internal conversion to the ground state and formation of rotamer E. In addition, opening of the chelated hydrogen ring by torsion of the hydroxyl group creates non-chelated enol. The possible mechanisms of rotamer Z formation are discussed. The solvent dependent photolability is related to the relative order of the lowest triplet ππ* and nπ* states of the keto tautomer. PMID:27443629

  20. Protective effects of 6-hydroxy-1-methylindole-3-acetonitrile on cisplatin-induced oxidative nephrotoxicity via Nrf2 inactivation.

    PubMed

    Moon, Ji Hee; Shin, Ji-Sun; Kim, Jong-Bin; Baek, Nam-In; Cho, Young-Wuk; Lee, Yong Sup; Kay, Hee Yeon; Kim, Soo-dong; Lee, Kyung-Tae

    2013-12-01

    We previously demonstrated the ethanol extract of the roots of Brassica rapa protects against cisplatin-induced nephrotoxicity by attenuating oxidative stress. Here, we investigated the nephroprotective effects of 6-hydroxy-1-methylindole-3-acetonitrile (6-HMA), which was isolated from the roots of B. rapa, on cisplatin-induced toxicity in renal epithelial LLC-PK1 cells and in rats with acute renal injury. Pretreatment of LLC-PK1 cells with 6-HMA ameliorated cisplatin-induced cytotoxicity caused by oxidative stress, as was demonstrated by reductions in the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and increased levels of glutathione (GSH). In addition, 6-HMA inhibited cisplatin-induced heme oxygenase-1 (HO-1) expression, possibly due to the suppression of the nuclear translocation and binding activity of NF-E2-related factor 2 (Nrf2). Furthermore, 6-HMA administered rats showed lower levels of blood urea nitrogen (BUN), creatinine, and urinary lactate dehydrogenase (LDH) than cisplatin alone-treated rats in cisplatin-induced renal injury model. Moreover, 6-HMA inhibited the cisplatin-induced formation of MDA and GSH depletion and increased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR). Taken together, these findings indicate 6-HMA is a major active constituent from the roots of B. rapa to have a protective effect against cisplatin-induced nephrotoxicity by attenuating oxidative stress. PMID:23989062

  1. Spectroscopic studies and molecular orbital calculations of charge transfer complexation between 3,5-dimethylpyrazole with DDQ in acetonitrile

    NASA Astrophysics Data System (ADS)

    Habeeb, Moustafa M.; Al-Attas, Amirah S.; Al-Raimi, Doaa S.

    2015-05-01

    Charge transfer (CT) interaction between 3,5-dimethylpyrazole (DMP) with the π-acceptor 2,3-dichloro-5,6-dicyano-p-benzoquinon (DDQ) has been investigated spectrophotometrically in acetonitrile (AN). Simultaneous reddish brown color has been observed upon mixing donor with acceptor solutions attributing to CT complex formation. The electronic spectra of the formed complex exhibited multi-charge transfer bands at 429, 447, 506, 542 and 589 nm, respectively. Job's method of continuous variations and spectrophotometric titration methods confirmed the formation of the studied complex in 1:2 ratio between DMP and DDQ. Benesi-Hildebrand equation has been applied to calculate the stability constant of the formed complex where it recorded high value supporting formation of stable complex. Molecular orbital calculations using MM2 method and GAMESS (General Atomic and Molecular Electronic Structure System) interface computations as a package of ChemBio3D Ultra12 software were carried out for more analysis of the formed complex in the gas phase. The computational analysis included energy minimisation, stabilisation energy, molecular geometry, Mullikan charges, molecular electrostatic potential (MEP) surfaces of reactants and complex as well as characterization of the higher occupied molecular orbitals (HOMO) and lower unoccupied molecular orbitals (LUMO) surfaces of the complex. A good consistency between experimental and theoretical results has been recorded.

  2. Identification of the amino-acetonitrile derivative monepantel (AAD 1566) as a new anthelmintic drug development candidate

    PubMed Central

    Gauvry, N.; Schorderet Weber, S.; Skripsky, T.; Bouvier, J.; Wenger, A.; Schroeder, F.; Desaules, Y.; Hotz, R.; Goebel, T.; Hosking, B. C.; Pautrat, F.; Wieland-Berghausen, S.; Ducray, P.

    2008-01-01

    Anthelmintic resistance has become a global phenomenon in gastro-intestinal nematodes of farm animals, including multi-drug resistance against the three major classes of anthelmintics. There is an urgent need for an anthelmintic with a new mode of action. The recently discovered amino-acetonitrile derivatives (AADs) offer a new class of synthetic chemicals with anthelmintic activity. The evaluation of AADs was pursued applying in vitro assays and efficacy and tolerability studies in rodents, sheep, and cattle. Amongst various suitable compounds, AAD 1566 eliminated many tested pathogenic nematode species, both at larval and adult stages, at a dose of 2.5 mg/kg bodyweight in sheep and 5.0 mg/kg bodyweight in cattle. The same doses were sufficient to cure animals infected with resistant or multi-drug-resistant nematode isolates. These findings, complemented by the good tolerability and low toxicity to mammals, suggest that AAD 1566, monepantel, would be a suitable anthelmintic drug development candidate. PMID:18594861

  3. Identification of 2-[4-[(4-Methoxyphenyl)methoxy]-phenyl]acetonitrile and Derivatives as Potent Oct3/4 Inducers.

    PubMed

    Cheng, Xinlai; Dimou, Eleni; Alborzinia, Hamed; Wenke, Frank; Göhring, Axel; Reuter, Stefanie; Mah, Nancy; Fuchs, Heiko; Andrade-Navarro, Miguel A; Adjaye, James; Gul, Sheraz; Harms, Christoph; Utikal, Jochen; Klipp, Edda; Mrowka, Ralf; Wölfl, Stefan

    2015-06-25

    Reprogramming somatic cells into induced-pluripotent cells (iPSCs) provides new access to all somatic cell types for clinical application without any ethical controversy arising from the use of embryonic stem cells (ESCs). Established protocols for iPSCs generation based on viral transduction with defined factors are limited by low efficiency and the risk of genetic abnormality. Several small molecules have been reported as replacements for defined transcriptional factors, but a chemical able to replace Oct3/4 allowing the generation of human iPSCs is still unavailable. Using a cell-based High Throughput Screening (HTS) campaign, we identified that 2-[4-[(4-methoxyphenyl)methoxy]phenyl]acetonitrile (1), termed O4I1, enhanced Oct3/4 expression. Structural verification and modification by chemical synthesis showed that O4I1 and its derivatives not only promoted expression and stabilization of Oct3/4 but also enhanced its transcriptional activity in diverse human somatic cells, implying the possible benefit from using this class of compounds in regenerative medicine. PMID:25898186

  4. Detection of Carbon Monoxide Using Polymer-Carbon Composite Films

    NASA Technical Reports Server (NTRS)

    Homer, Margie L.; Ryan, Margaret A.; Lara, Liana M.

    2011-01-01

    A carbon monoxide (CO) sensor was developed that can be incorporated into an existing sensing array architecture. The CO sensor is a low-power chemiresistor that operates at room temperature, and the sensor fabrication techniques are compatible with ceramic substrates. Sensors made from four different polymers were tested: poly (4-vinylpryridine), ethylene-propylene-diene-terpolymer, polyepichlorohydrin, and polyethylene oxide (PEO). The carbon black used for the composite films was Black Pearls 2000, a furnace black made by the Cabot Corporation. Polymers and carbon black were used as received. In fact, only two of these sensors showed a good response to CO. The poly (4-vinylpryridine) sensor is noisy, but it does respond to the CO above 200 ppm. The polyepichlorohydrin sensor is less noisy and shows good response down to 100 ppm.

  5. Facile preparation of superamphiphobic epoxy resin/modified poly(vinylidene fluoride)/fluorinated ethylene propylene composite coating with corrosion/wear-resistance

    NASA Astrophysics Data System (ADS)

    Wang, Huaiyuan; Liu, Zhanjian; Wang, Enqun; Zhang, Xiguang; Yuan, Ruixia; Wu, Shiqi; Zhu, Yanji

    2015-12-01

    A robust superamphiphobic epoxy resin (EP)/modified poly(vinylidene fluoride) (MPVDF)/fluorinated ethylene propylene (FEP) composite coating has been prepared through the combination of chemical modification and spraying technique. Nanometer silica (SiO2, 2.5 wt.%) and carbon nanotubes (CNTs, 2.5 wt.%) were added in the coating to construct the necessary reticulate papillae structures for superamphiphobic surface. The prepared EP composite coating demonstrated high static contact angles (166°, 155°) and low sliding angles (3°, 5°) to water and glycerol, respectively. Moreover, the prepared coating can also retain superhydrophobicity under strongly acidic and alkaline conditions. The brittleness of EP can be avoided by introducing the malleable MPVDF. The wear life of the EP composite coating with 25 wt.% FEP was improved to 18 times of the pure EP coating. The increased wear life of the coating can be attributed to the designed nano/micro structures, the self-lubrication of FEP and the chemical reaction between EP and MPVDF. The anti-corrosion performance of the coatings was investigated in 3.5% NaCl solution using potentiodynamic polarization. The results showed that the prepared superamphiphobic composite coating was most effective in corrosion resistance, primarily due to the barrier effect for the diffusion of O2 and H2O molecules. It is believed that this robust superamphiphobic EP/MPVDF/FEP composite coating prepared by the facile spray method can pave a way for the large-scale application in pipeline transport.

  6. Selective production of 1,2-propylene glycol from Jerusalem artichoke tuber using Ni-W(2) C/AC catalysts.

    PubMed

    Zhou, Likun; Wang, Aiqin; Li, Changzhi; Zheng, Mingyuan; Zhang, Tao

    2012-05-01

    A series of Ni-promoted W(2) C/activated carbon (AC) catalysts were investigated for the catalytic conversion of Jerusalem artichoke tuber (JAT) under hydrothermal conditions and hydrogen pressure. Even a small amount of Ni could greatly promote the conversion of JAT to 1,2-propylene glycol (1,2-PG), whereas the pure W(2) C/AC catalyst resulted in the selective formation of acetol. The product distribution profiles involving the reaction temperature, time, and H(2) pressure indicated that 1,2-PG formed as a result of acetol hydrogenation, which was catalyzed by Ni. Thus, there was a synergy between W(2) C and Ni, and the best performance yielded 38.5% of 1,2-PG over a 4%Ni-20%W(2) C/AC catalyst at 245°C, 6 MPa H(2) , and 80 min. To understand the reaction process, some important intermediates, such as inulin, fructose, acetol, glyceraldehyde, and 1,3-dihydroxyacetone, were used as the feedstock. Based on the product distributions derived from these intermediates, a reaction pathway was proposed, where JAT was first hydrolyzed into a mixture of fructose and glucose under the catalysis of H(+) , then the sugars underwent a retro-aldol reaction followed by hydrogenation catalyzed by Ni-W(2) C. PMID:22407966

  7. [Heat resistance of "Bacillus subtilis" and "Bacillus stearothermophilus" spores in ethylene glycol, propylene glycol and butylene glycol solutions. Criticism of the use of thermodynamic parameters (author's transl)].

    PubMed

    Cerf, O; L'Haridon, R; Hermier, J

    1975-01-01

    Increasing concentrations of ethylene glycol (EG), 1,2-propylene glycol (PG) or 2,3-butylene glycol (BG) lower the heat resistance of B. subtilis SJ2 and B. stearothermophilus 1518 spores, and there is a linear relationship between logarithm of decimal reduction time (D) and glycol concentration. D120 degreesc values of B. subtilis spores in 0.02M, pH 7.0 phosphate buffer containing 20 per cent (w/w) EG, PG and BG are respectively 1, 0.7 and 1.1 min compared to 1.5 min in buffer alone. Corresponding values for B. stearothermophilus spores are 2, 2.4 and 3 min compared to 3.2 min. The type of glycol has little effect upon temperature coefficient z for destruction of the B. subtilis spores (average 6.9 degrees C). On the contrary, in the case of B. stearothermophilus, z increases when the number of carbons increases in the glycol molecule (from 7 to 15 degrees). The thermodynamic parameters which characterize the activation of the spore destruction reaction cannot lead to a general conclusion about a possible mechanism of destruction in the presence of chemical compounds belonging to an homologous series: the two behave diversely, and there is no "isokinetic temperature". PMID:811145

  8. Glass transition and relaxation dynamics of propylene glycol-water solutions confined in clay.

    PubMed

    Elamin, Khalid; Björklund, Jimmy; Nyhlén, Fredrik; Yttergren, Madeleine; Mårtensson, Lena; Swenson, Jan

    2014-07-21

    The molecular dynamics of aqueous solutions of propylene glycol (PG) and propylene glycol methylether (PGME) confined in a two-dimensional layer-structured Na-vermiculite clay has been studied by broadband dielectric spectroscopy and differential scanning calorimetry. As typical for liquids in confined geometries the intensity of the cooperative α-relaxation becomes considerably more suppressed than the more local β-like relaxation processes. In fact, at high water contents the calorimetric glass transition and related structural α-relaxation cannot even be observed, due to the confinement. Thus, the intensity of the viscosity related α-relaxation is dramatically reduced, but its time scale as well as the related glass transition temperature Tg are for both systems only weakly influenced by the confinement. In the case of the PGME-water solutions it is an important finding since in the corresponding bulk system a pronounced non-monotonic concentration dependence of the glass transition related dynamics has been observed due to the growth of hydrogen bonded relaxing entities of water bridging between PGME molecules [J. Sjöström, J. Mattsson, R. Bergman, and J. Swenson, Phys. Chem. B 115, 10013 (2011)]. The present results suggest that the same type of structural entities are formed in the quasi-two-dimensional space between the clay platelets. It is also observed that the main water relaxation cannot be distinguished from the β-relaxation of PG or PGME in the concentration range up to intermediate water contents. This suggests that these two processes are coupled and that the water molecules affect the time scale of the β-relaxation. However, this is most likely true also for the corresponding bulk solutions, which exhibit similar time scales of this combined relaxation process below Tg. Finally, it is found that at higher water contents the water relaxation does not merge with, or follow, the α-relaxation above Tg, but instead crosses the

  9. Glass transition and relaxation dynamics of propylene glycol-water solutions confined in clay

    NASA Astrophysics Data System (ADS)

    Elamin, Khalid; Björklund, Jimmy; Nyhlén, Fredrik; Yttergren, Madeleine; Mârtensson, Lena; Swenson, Jan

    2014-07-01

    The molecular dynamics of aqueous solutions of propylene glycol (PG) and propylene glycol methylether (PGME) confined in a two-dimensional layer-structured Na-vermiculite clay has been studied by broadband dielectric spectroscopy and differential scanning calorimetry. As typical for liquids in confined geometries the intensity of the cooperative α-relaxation becomes considerably more suppressed than the more local β-like relaxation processes. In fact, at high water contents the calorimetric glass transition and related structural α-relaxation cannot even be observed, due to the confinement. Thus, the intensity of the viscosity related α-relaxation is dramatically reduced, but its time scale as well as the related glass transition temperature Tg are for both systems only weakly influenced by the confinement. In the case of the PGME-water solutions it is an important finding since in the corresponding bulk system a pronounced non-monotonic concentration dependence of the glass transition related dynamics has been observed due to the growth of hydrogen bonded relaxing entities of water bridging between PGME molecules [J. Sjöström, J. Mattsson, R. Bergman, and J. Swenson, Phys. Chem. B 115, 10013 (2011)]. The present results suggest that the same type of structural entities are formed in the quasi-two-dimensional space between the clay platelets. It is also observed that the main water relaxation cannot be distinguished from the β-relaxation of PG or PGME in the concentration range up to intermediate water contents. This suggests that these two processes are coupled and that the water molecules affect the time scale of the β-relaxation. However, this is most likely true also for the corresponding bulk solutions, which exhibit similar time scales of this combined relaxation process below Tg. Finally, it is found that at higher water contents the water relaxation does not merge with, or follow, the α-relaxation above Tg, but instead crosses the

  10. Characterization of uranium surfaces machined with aqueous propylene glycol-borax or perchloroethylene-mineral oil coolants

    SciTech Connect

    Cristy, S.S.; Bennett, R.K. Jr.; Dillon, J.J.; Richards, H.L.; Seals, R.D.; Byrd, V.R.

    1986-12-31

    The use of perchloroethylene (perc) as an ingredient in coolants for machining enriched uranium at the Oak Ridge Y-12 Plant has been discontinued because of environmental concerns. A new coolant was substituted in December 1985, which consists of an aqueous solution of propylene glycol with borax (sodium tetraborate) added as a nuclear poison and with a nitrite added as a corrosion inhibitor. Uranium surfaces machined using the two coolants were compared with respects to residual contamination, corrosion or corrosion potential, and with the aqueous propylene glycol-borax coolant was found to be better than that of enriched uranium machined with the perc-mineral oil coolant. The boron residues on the final-finished parts machined with the borax-containing coolant were not sufficient to cause problems in further processing. All evidence indicated that the enriched uranium surfaces machined with the borax-containing coolant will be as satisfactory as those machined with the perc coolant.

  11. Europium, uranyl, and thorium-phenanthroline amide complexes in acetonitrile solution: an ESI-MS and DFT combined investigation.

    PubMed

    Xiao, Cheng-Liang; Wang, Cong-Zhi; Mei, Lei; Zhang, Xin-Rui; Wall, Nathalie; Zhao, Yu-Liang; Chai, Zhi-Fang; Shi, Wei-Qun

    2015-08-28

    The tetradentate N,N'-diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) ligand with hard-soft donor atoms has been demonstrated to be promising for the group separation of actinides from highly acidic nuclear wastes. To identify the formed complexes of this ligand with actinides and lanthanides, electrospray ionization mass spectrometry (ESI-MS) combined with density functional theory (DFT) calculations was used to probe the possible complexation processes. The 1 : 2 Eu-L species ([EuL2(NO3)](2+)) can be observed in ESI-MS at low metal-to-ligand ([M]/[L]) ratios, whereas the 1 : 1 Eu-L species ([EuL(NO3)2](+)) can be observed when the [M]/[L] ratio is higher than 1.0. However, ([UO2L(NO3)](+)) is the only detected species for the uranyl complexes. The [ThL2(NO3)2](2+) species can be observed at low [M]/[L] ratios; the 1 : 2 species ([ThL2(NO3)](3+)) and a new 1 : 1 species ([ThL(NO3)3](+)) can be detected at high [M]/[L] ratios. Collision-induced dissociation (CID) results showed that Et-Tol-DAPhen ligands can coordinate strongly with metal ions, and the coordination moieties remain intact under CID conditions. Natural bond orbital (NBO), molecular electrostatic potential (MEP), electron localization function (ELF), atoms in molecules (AIM) and molecular orbital (MO) analyses indicated that the metal-ligand bonds of the actinide complexes exhibited more covalent character than those of the lanthanide complexes. In addition, according to thermodynamic analysis, the stable cationic M-L complexes in acetonitrile are found to be in good agreement with the ESI-MS results. PMID:26200662

  12. Acetonitrile extraction and dual-layer solid phase extraction clean-up for pesticide residue analysis in propolis.

    PubMed

    Oellig, Claudia

    2016-05-01

    Propolis is a very complex mixture of substances that is produced by honey bees and is known to be a rather challenging matrix for residue analysis. Besides resins, flavonoids and phenols, high amount of wax is co-extracted resulting in immense matrix effects. Therefore a suitable clean-up is crucial and indispensable. In this study, a reliable solid phase extraction (SPE) clean-up was developed for pesticide residue analysis in propolis. The clean-up success was quickly and easily monitored by high-performance thin-layer chromatography with different detection possibilities. The final method consists of the extraction of propolis with acetonitrile according to the QuEChERS method followed by an effective extract purification on dual-layer SPE cartridges with spherical hydrophobic polystyrene-divinylbenzene resin/primary secondary amine as sorbent and a mixture of toluene/acetone (95:5, v/v) for elution. Besides fat-soluble components like waxes, flavonoids, and terpenoids, more polar compounds like organic acids, fatty acids, sugars and anthocyanins were also removed to large extent. Method performance was assessed by recovery experiments at spiking levels of 0.5 and 1mg/kg (n=5) for fourteen pesticides that are relevant for propolis. Mean recoveries determined by HPLC-MS against solvent standards were between 40 and 101%, while calculation against matrix-matched standards provided recoveries of 79-104%. Precision of recovery, assessed by relative standard deviations, were below 9%. Thus, the developed dual-layer SPE clean-up enables the reliable pesticide residue analysis in propolis and provides a suitable alternative to time-consuming clean-up procedures proposed in literature. PMID:27059398

  13. Direct Epoxidation of Propylene over Stabilized Cu+ Surface Sites on Ti Modified Cu2O

    SciTech Connect

    Yang, X.; Kattel, S.; Xiong, K.; Mudiyanselage, K.; Rykov, S.; Senanayake, S. D.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G.

    2015-07-17

    Direct propylene epoxidation by O2 is a challenging reaction because of the strong tendency for complete combustion. Results from the current study demonstrate the feasibility to tune the epoxidation selectivity by generating highly dispersed and stabilized Cu+ active sites in a TiCuOx mixed oxide. The TiCuOx surface anchors the key surface intermediate, oxametallacycle, leading to higher selectivity for epoxidation of propylene.

  14. Systematic study on the influence of the morphology of α-MoO3 in the selective oxidation of propylene

    NASA Astrophysics Data System (ADS)

    Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin; Jensen, Anker Degn; Beato, Pablo; Patzke, Greta R.; Grunwaldt, Jan-Dierk

    2015-08-01

    A variety of morphologically different α-MoO3 samples were prepared by hydrothermal synthesis and applied in the selective oxidation of propylene. Their catalytic performance was compared to α-MoO3 prepared by flame spray pyrolysis (FSP) and a classical synthesis route. Hydrothermal synthesis from ammonium heptamolybdate (AHM) and nitric acid at pH 1-2 led to ammonium containing molybdenum oxide phases that were completely transformed into α-MoO3 after calcination at 550 °C. A one-step synthesis of α-MoO3 rods was possible starting from MoO3·2H2O with acetic acid or nitric acid and from AHM with nitric acid at 180 °C. Particularly, if nitric acid was used during synthesis, the rod-like morphology of the samples could be stabilized during calcination at 550 °C and the following catalytic activity tests, which was beneficial for the catalytic performance in propylene oxidation. Characterization studies using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy showed that those samples, which retained their rod-like morphology during the activity tests, yielded the highest propylene conversion.

  15. Artificial sunlight and ultraviolet light induced photo-epoxidation of propylene over V-Ti/MCM-41 photocatalyst

    PubMed Central

    Nguyen, Van-Huy; Bai, Hsunling

    2014-01-01

    Summary The light irradiation parameters, including the wavelength spectrum and intensity of light source, can significantly influence a photocatalytic reaction. This study examines the propylene photo-epoxidation over V-Ti/MCM-41 photocatalyst by using artificial sunlight (Xe lamp with/without an Air Mass 1.5 Global Filter at 1.6/18.5 mW·cm−2) and ultraviolet light (Mercury Arc lamp with different filters in the range of 0.1–0.8 mW·cm−2). This is the first report of using artificial sunlight to drive the photo-epoxidation of propylene. Over V-Ti/MCM-41 photocatalyst, the propylene oxide (PO) formation rate is 193.0 and 112.1 µmol·gcat −1·h−1 with a PO selectivity of 35.0 and 53.7% under UV light and artificial sunlight, respectively. A normalized light utilization (NLU) index is defined and found to correlate well with the rate of both PO formation and C3H6 consumption in log–log scale. The light utilization with a mercury arc lamp is better than with a xenon lamp. The selectivity to PO remains practically unchanged with respect to NLU, suggesting that the photo-epoxidation occurs through the same mechanism under the conditions tested in this study. PMID:24991493

  16. In vivo quantification of propylene glycol, glucose and glycerol diffusion in human skin with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Guo, X.; Guo, Z. Y.; Wei, H. J.; Yang, H. Q.; He, Y. H.; Xie, S. S.; Wu, G. Y.; Zhong, H. Q.; Li, L. Q.; Zhao, Q. L.

    2010-09-01

    The purpose of study is to quantify and compare diffusion of propylene glycol, glucose, glycerol in the human skin in vivo noninvasively. Optical coherence tomography (OCT) was utilized in the functional imaging of optical cleaning agents for monitoring and quantifying the permeability coefficients (PCs) of them. Our experiments showed that the permeability coefficient of 40% propylene glycol from different subjects was averaged and found to be (2.52 ± 0.02) × 10-6 cm/s, the permeability coefficient of 40% glucose was (1.94 ± 0.05) × 10-6 cm/s, and the permeability coefficient of 40% glycerol was (1.82 ± 0.04) × 10-6 cm/s. The results indicated that the diffusion of propylene glycol solutions was faster than that of glucose solution, and the diffusion of glucose solutions was faster than that of glycerol solutions. The dependence of the permeability on the different hyperosmotic analytes could potentially be used in various basic science and clinical fields, such as optical clearing of tissues and cells as well as in clinical pharmacology.

  17. Electrochemical characterization of poly-(3,4 propylene-dioxythiophene) pseudo-capacitor

    NASA Astrophysics Data System (ADS)

    Sahoo, H.; Park, J. W.; Cardona, R. A.; Santiago-Avilés, J.

    2013-03-01

    Every day use of appliances relies mostly in lithium-ion batteries to satisfy their energy requirements. However, the materials utilized and their lower power densities limit these batteries' desirability. An alternative to batteries is the supercapacitors, which are capable of storing energy in the electrical double layer (EDL) formed between the electrode material and the electrolyte. To reduce the gap in terms on energy and power density between batteries and EDL supercapacitor, pseudocapacitors has been used. In pseudo-capacitors a material that is capable of storing faradaic charge, such as metal oxides and conducting polymers, is deposited in the electrode surface, but its charge / discharge behavior approximate that of the EDL supercapacitor. Therefore, energy density is gained even though the faradaic nature of the process makes its power density decreases. In this paper, we use the conducting polymer, poly-(3,4 propylene-dioxythiophene) for the assembling of a pseudo-capacitor. We present the electrochemical characterization of the devices as a function of the amount of material accumulated in the platinum current collector, in terms of the capacitance, energy, and power density.

  18. Economic value of ionophores and propylene glycol to prevent disease and treat ketosis in Canada.

    PubMed

    Gohary, Khaled; Overton, Michael W; Von Massow, Michael; LeBlanc, Stephen J; Lissemore, Kerry D; Duffield, Todd F

    2016-07-01

    A partial budget model was developed to evaluate the economic value of Rumensin Controlled Release Capsule (CRC) boluses when administered before calving to reduce disease and increase milk production. After accounting for disease incidences in a herd and the percentage by which Rumensin CRC can reduce them, and the increase in milk production attributable to administration of Rumensin CRC, the return on investment (ROI) per lactation was 4:1. Another partial budget model was developed to estimate the economic value of propylene glycol (PG) to treat ketosis when diagnosed by 3 different cow-side tests or when administered to all cows without using any cow-side testing. After accounting for the sensitivity and specificity of each test, ROI per lactation ranged from 2:1 to 4:1. The ROI was 2:1 when no cow-side testing was used. In conclusion, prevention of diseases that occur in the postpartum period and treatment of ketosis after calving yielded a positive ROI that varies based on disease incidence and method of diagnosis. PMID:27429461

  19. Coarse-grained simulations of poly(propylene imine) dendrimers in solution.

    PubMed

    Smeijers, A F; Markvoort, A J; Pieterse, K; Hilbers, P A J

    2016-02-21

    The behavior of poly(propylene imine) (PPI) dendrimers in concentrated solutions has been investigated using molecular dynamics simulations containing up to a thousand PPI dendrimers of generation 4 or 5 in explicit water. To deal with large system sizes and time scales required to study the solutions over a wide range of dendrimer concentrations, a previously published coarse-grained model was applied. Simulation results on the radius of gyration, structure factor, intermolecular spacing, dendrimer interpenetration, and water penetration are compared with available experimental data, providing a clear concentration dependent molecular picture of PPI dendrimers. It is shown that with increasing concentration the dendrimer volume diminishes accompanied by a reduction of internalized water, ultimately resulting in solvent filled cavities between stacked dendrimers. Concurrently dendrimer interpenetration increases only slightly, leaving each dendrimer a separate entity also at high concentrations. Moreover, we compare apparent structure factors, as calculated in experimental studies relying on the decoupling approximation and the constant atomic form factor assumption, with directly computed structure factors. We demonstrate that these already diverge at rather low concentrations, not because of small changes in form factor, but rather because the decoupling approximation fails as monomer positions of separate dendrimers become correlated at concentrations well below the overlap concentration. PMID:26896998

  20. Dynamics and acoustics of a cavitating Venturi flow using a homogeneous air-propylene glycol mixture

    NASA Astrophysics Data System (ADS)

    Navarrete, M.; Naude, J.; Mendez, F.; Godínez, F. A.

    2015-12-01

    Dynamics and acoustics generated in a cavitating Venturi tube are followed up as a function of the input power of a centrifugal pump. The pump of 5 hp with a modified impeller to produce uniform bubbly flow, pumps 70 liters of propylene glycol in a closed loop (with a water cooling system), in which the Venturi is arranged. The goal was to obtain correlations among acoustical emission, dynamics of the shock waves and the light emission from cavitation bubbles. The instrumentation includes: two piezoelectric transducers, a digital camera, a high-speed video camera, and photomultipliers. As results, we show the cavitation patterns as function of the pump power, and a graphical template of the distribution of the Venturi conditions as a function of the cavitation parameter. Our observations show for the first time the sudden formation of bubble clouds in the straight portion of the pipe after the diverging section of the Venturi. We assume that this is due to pre-existing of nuclei-cloud structures which suddenly grow up by the tensile tails of propagating shock waves (producing a sudden drop in pressure).

  1. Life's First Handshake - Discovery of the Interstellar Chiral Molecule Propylene Oxide

    NASA Astrophysics Data System (ADS)

    McGuire, Brett A.; Carroll, P. Brandon; Loomis, Ryan A.; Finneran, Ian A.; Jewell, Philip R.; Remijan, Anthony J.; Blake, Geoffrey A.

    2016-06-01

    Life on Earth relies on chiral molecules, that is, species not superimposable on their mirror images. This manifests itself in the selection of a single molecular handedness, or homochirality, across the biosphere, and is perhaps most readily apparent in the large enhancement in biological activity of particular amino acid and sugar enantiomers. Yet, the ancestral origin of biological homochirality remains a mystery. The non-racemic ratios in some organics isolated from primitive meteorites hint at a primordial chiral seed, but even these samples have experienced substantial processing during planetary assembly, obscuring their complete histories. To determine the underlying origin of any enantiomeric excess, it is critical to understand the molecular gas from which these molecules originated. Here, we present the first extra-solar, astronomical detection of a chiral molecule, propylene oxide (CH3CHCH2O), in absorption toward the Galactic Center. We discuss the implications of the detection on observational searches to determine a primordial chiral excess, as well as the state of laboratory efforts in these areas.

  2. Raman and Brillouin scattering of LiClO4 complexed in poly(propylene-glycol)

    NASA Astrophysics Data System (ADS)

    Schantz, S.; Torell, L. M.; Stevens, J. R.

    1988-08-01

    Raman spectra of LiClO4 complexed in poly(propylene-glycol) (PPG) have been obtained for concentrations of the monomer to salt ratio (ether oxygen):Li in the range 30:1-5:1. Splitting of the symmetric stretching mode of the ClO4- anion was observed with an intensity profile that varied with salt concentration. This phenomenon indicates a changing environment about the anion. A two-component band analysis leads to the identification of dissociated ions on one hand and solvent-separated ion pairs on the other. The concentration of ion pairs is relatively low compared to that of the dissociated ions, which are predominant for all concentrations. Despite the observed increase in the absolute number of dissociated ions at higher salt concentration, the electrical conductivity is reported to decrease in the same range. This indicates that the number of ``free'' charge carriers is of less importance for the conductivity than the mobility, which is damped in this concentration range. Frequency shifts of the disordered longitudinal-acoustic mode and increased hypersonic velocities, measured with Raman and Brillouin scattering techniques, respectively, indicate increased stiffness of the polymer matrix for increasing salt concentration, which probably results in decreased ion mobility.

  3. Structure of Poly(styrene-b-ethylene-alt-propylene) Diblock Copolymer Micelles in Squalane

    SciTech Connect

    Choi, Soo-Hyung; Bates, Frank S.; Lodge, Timothy P.

    2009-11-04

    The temperature dependence of the micellar structures formed by poly(styrene-b-ethylene-alt-propylene) (SEP) diblock copolymers in squalane, a highly selective solvent for the PEP blocks, has been studied using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS). Four SEP diblock copolymers were prepared by sequential anionic polymerization of styrene and isoprene, followed by hydrogenation of the isoprene blocks, to yield SEP(17-73), SEP(26-66), SEP(36-69), and SEP(42-60), where the numbers indicate block molecular weights in kDa. All four polymers formed well-defined spherical micelles. In dilute solution, DLS provided the temperature-dependent mean hydrodynamic radius, R{sub h}, and its distribution, while detailed fitting of the SAXS profiles gave the core radius, R{sub c}, the equivalent hard sphere radius, R{sub hs}, and an estimate of the aggregation number, N{sub agg}. In general, the micelles became smaller as the critical micelle temperature (CMT) was approached, which was well above the glass transition of the core block. As concentration increased the micelles packed onto body centered cubic lattices for all four copolymers, which underwent order-disorder transitions upon heating near the dilute solution CMTs. The results are discussed in terms of current understanding of block copolymer solution self-assembly, and particular attention is paid to the issue of equilibration, given the high glass transition temperature of the core block.

  4. Codiffusion of propylene glycol and dimethyl isosorbide in hairless mouse skin.

    PubMed

    Squillante, E; Needham, T; Maniar, A; Kislalioglu, S; Zia, H

    1998-11-01

    The in vitro percutaneous fluxes of propylene glycol (PG), cis-oleic acid (OA) and dimethyl isosorbide (DI) were determined and their effect on nifedipine (N) flux and lag time evaluated. PG, OA and DI flux through hairless mouse (HM) skin was measured in vitro by beta-scintigraphy and N permeation was measured by HPLC under finite and infinite dose conditions. Evaluation of each of the solvents separately showed that pure DI possessed the inherent ability to traverse the skin (12% in 24 h). For the tested formulation after 24 h, 57% of the PG and 40% of the DI had permeated across the skin with nearly linear permeation between 4 and 18 h and the relative order of permeation was PG > DI > N. DI permeation was further aided in the presence of PG and OA. N flux was dependent on concomitant solvent permeation. Over a 24-h test period a dose dependent response was observed for N, with 4.9-15.6 mg of N delivered from the lowest and highest doses, respectively, and the highest dose yielding zero-order flux of 146 (g/h per cm2). PMID:9885297

  5. Poly(propylene fumarate)/Polyethylene Glycol-Modified Graphene Oxide Nanocomposites for Tissue Engineering.

    PubMed

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2016-07-20

    Poly(propylene fumarate) (PPF)-based nanocomposites incorporating different amounts of polyethylene glycol-functionalized graphene oxide (PEG-GO) have been prepared via sonication and thermal curing, and their surface morphology, structure, thermal stability, hydrophilicity, water absorption, biodegradation, cytotoxicity, mechanical, viscoelastic and antibacterial properties have been investigated. SEM and TEM images corroborated that the noncovalent functionalization with PEG caused the exfoliation of GO into thinner flakes. IR spectra suggested the presence of strong hydrogen-bonding interactions between the nanocomposite components. A gradual rise in the level of hydrophilicity, water uptake, biodegradation rate, surface roughness, protein absorption capability and thermal stability was found upon increasing GO concentration in the composites. Tensile tests revealed improved stiffness, strength and toughness for the composites compared to unfilled PPF, ascribed to a homogeneous GO dispersion within the matrix along with a strong PPF/PEG-GO interfacial adhesion via polar and hydrogen bonding interactions. Further, the nanocomposites retained enough stiffness and strength under a biological state to provide effective support for bone tissue formation. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus and Staphylococcus epidermidis as well as Gram-negative Pseudomonas aeruginosa and Escherichia coli microorganisms, and it rose sharply upon increasing GO concentration; systematically, the biocide effect was stronger versus Gram-positive bacteria. Cell viability data demonstrated that PPF/PEG-GO composites do not induce toxicity over human dermal fibroblasts. These novel materials show great potential to be applied in the bone tissue engineering field. PMID:27383639

  6. Analysis of a vinyl pyrrolidone/poly(propylene fumarate) resorbable bone cement.

    PubMed

    Gresser, J D; Hsu, S H; Nagaoka, H; Lyons, C M; Nieratko, D P; Wise, D L; Barabino, G A; Trantolo, D J

    1995-10-01

    A resorbable bone cement was formulated from N-vinyl-2-pyrrolidinone (VP), the unsaturated polyester poly(propylene fumarate) (PPF), and the inorganic filler tribasic calcium phosphate (hydroxy apatite). Cure, initiated by benzoyl peroxide and accelerated by N,N-dimethyl-p-toluidine, resulted in the formation of VP crosslinks between polyester chains. During cure the cement hardened from a viscous moldable putty to a rigid structure with a shore D hardness of 50-60. The purpose of this study was to determine the fractions of PPF and VP incorporated into the crosslinked structure. Dissolution of the cured cement in water followed by extraction of the residue in tetrahydrofuran indicated that over 90% of the PPF was crosslinked over the range of PPF/VP ratios explored, but that the fraction of VP used in formation of crosslinks depended linearly on the PPF/VP ratio. Kinetic analysis of these data suggests that k'pp/kpf (the reactivity ratio) was approximately 2.0 where k'pp is the rate constant for the addition of VP radical to VP monomer leading to formation of poly(vinyl pyrrolidone), and kpf is for the addition of VP radical to PPF unsaturation. PMID:8557726

  7. Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species.

    PubMed

    Allen, Brett L; Johnson, Jermaine D; Walker, Jeremy P

    2012-07-27

    In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC 3.1.8.2), has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase's stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme's exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a 'sacrificial barrier' by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase-PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC 1.11.1.10) reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO(2) (100 ppm). PMID:22743846

  8. Experiments on Charge Generation in Cross-linked Polyethylene and Ethylene-Propylene Copolymer

    NASA Astrophysics Data System (ADS)

    Sekii, Yasuo; Taya, Atsushi; Suzuki, Hirokazu; Maeno, Takashi

    To study the space charge generation in cross-linked polyethylene (XLPE) and ethylene propylene copolymer (EPR), space charge profiles in both materials are measured using PEA method. The experimental results demonstrated that a big difference was discovered in the detected charge profiles between XLPE and EPR. We discovered that the diffusion of charge is significantly faster in EPR than in XLPE. The authors confirmed that the negative hetero-charge is generated near the positive electrode in EPR when moisture are coexisting with acetophenone. The effects of antioxidants on the generation of hetero-space charges in XLPE and EPR are also studied using XLPE and EPR samples containing different kinds of phenolic and sulfur type antioxidant. The authors discovered that hetero-charge is generated in XLPE and EPR containing sulfur type, or sulfur-containing phenolic, antioxidant when acetophenone are existing in the material. The hetero-charge generation is inferred to be caused by the combined effect between acetophenone and the component containing sulfur atoms of the antioxidants.

  9. Response of ethylene propylene diene monomer rubber (EPDM) to simulant Hanford tank waste

    SciTech Connect

    NIGREY,PAUL J.

    2000-02-01

    This report presents the findings of the Chemical Compatibility Program developed to evaluate plastic packaging components that may be incorporated in packaging mixed-waste forms for transportation. Consistent with the methodology outlined in this report, the author performed the second phase of this experimental program to determine the effects of simulant Hanford tank mixed wastes on packaging seal materials. That effort involved the comprehensive testing of five plastic liner materials in an aqueous mixed-waste simulant. The testing protocol involved exposing the materials to {approximately}143, 286, 571, and 3,670 krad of gamma radiation and was followed by 7-, 14-, 28-, 180-day exposures to the waste simulant at 18, 50, and 60 C. Ethylene propylene diene monomer (EPDM) rubber samples subjected to the same protocol were then evaluated by measuring seven material properties: specific gravity, dimensional changes, mass changes, hardness, compression set, vapor transport rates, and tensile properties. The author has determined that EPDM rubber has excellent resistance to radiation, this simulant, and a combination of these factors. These results suggest that EPDM is an excellent seal material to withstand aqueous mixed wastes having similar composition to the one used in this study.

  10. Microstereolithography and characterization of poly(propylene fumarate)-based drug-loaded microneedle arrays.

    PubMed

    Lu, Yanfeng; Mantha, Satya Nymisha; Crowder, Douglas C; Chinchilla, Sofia; Shah, Kush N; Yun, Yang H; Wicker, Ryan B; Choi, Jae-Won

    2015-01-01

    Drug-loaded microneedle arrays for transdermal delivery of a chemotherapeutic drug were fabricated using multi-material microstereolithography (μSL). These arrays consisted of twenty-five poly(propylene fumarate) (PPF) microneedles, which were precisely orientated on the same polymeric substrate. To control the viscosity and improve the mechanical properties of the PPF, diethyl fumarate (DEF) was mixed with the polymer. Dacarbazine, which is widely used for skin cancer, was uniformly blended into the PPF/DEF solution prior to crosslinking. Each microneedle has a cylindrical base with a height of 700 μm and a conical tip with a height of 300 μm. Compression test results and characterization of the elastic moduli of the PPF/DEF (50:50) and PPF/drug mixtures indicated that the failure force was much larger than the theoretical skin insertion force. The release kinetics showed that dacarbazine can be released at a controlled rate for five weeks. The results demonstrated that the PPF-based drug-loaded microneedles are a potential method to treat skin carcinomas. In addition, μSL is an attractive manufacturing technique for biomedical applications, especially for micron-scale manufacturing. PMID:26418306

  11. Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species

    NASA Astrophysics Data System (ADS)

    Allen, Brett L.; Johnson, Jermaine D.; Walker, Jeremy P.

    2012-07-01

    In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC 3.1.8.2), has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase’s stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme’s exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a ‘sacrificial barrier’ by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase-PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC 1.11.1.10) reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO2 (100 ppm).

  12. Ac-electrical conductivity of poly(propylene) before and after X-ray irradiation

    NASA Astrophysics Data System (ADS)

    Gaafar, M.

    2001-05-01

    Study on the ac-electrical conductivity of poly(propylene), before and after X-ray irradiation within the temperature range 300-360 K are reported. The measurements have been performed in a wide range of frequencies (from 0 to 10 5 Hz) and under the effect of different X-ray irradiation doses (from 0 to 15 Gy). Cole-Cole diagrams have been used to show the frequency dependence of the complex impedance at different temperatures. The results exhibit semicircles which are consistent with existing equivalent circuit model. Analysis of the results reveal semiconducting features based mainly on a hopping mechanism. The study shows a pronounced effect of X-ray irradiation on the electrical conductivity at zero frequency σDC. At the early stage of irradiation, σDC increased as a result of free radical formation. As the irradiation progressed, it decreased as a result of crosslinking, then it increased again due to irradiation induced degradation, which motivates the generation of mobile free radicals. The study shows that this polymer is one among other polymers which its electrical conductivity is modified by irradiation.

  13. Silane cross-linkable ethylene-propylene elastomer compositions prepared by reactive processing

    NASA Astrophysics Data System (ADS)

    Kozawa, Eiji; Nakajima, Yasuo; Kim, Jae Kyung

    2015-05-01

    Thermoplastic Elastomers (TPEs) have received attention as the alternative materials of EPDM due to an advantage for mass production. In recent years, by the progress of polymerization technology, Ethylene-propylene Elastomer (EP), one of the TPEs, is beginning to be applied to many products because of its good properties as rubber. However, as much as a complete replacement for EPDM, it is not provided with sufficient properties. In such circumstance, we found that EP's performance properties can be further enhanced via chemical modification such as cross-linking. The advent of a newer technique, involving the grafting of organo-functional silane onto the polymer chain in the reaction extrusion process is more attractive due to various industrial advantages. Although the functionalization of the EP by silane grafting through reactive processing is very useful, the silane grafting process of EP has a difficulty. It is most likely a consequence of the nature of the PP chain scission (β-scission), which is the dominant reaction in PP when subjected to free radicals at elevated temperature during processing. Therefore, the objective of our current work is to investigate a reactive extrusion process for the silane cross-linkable EP while minimizing the degradation, as well as evaluate the properties of the modified polymer.

  14. Structure Evolution of Propylene-1-Butylene Random Copolymer under Uniaxial Stretching: from Unit Cells to Lamellae

    NASA Astrophysics Data System (ADS)

    Mao, Yimin; Burger, Christian; Li, Xiaowei; Hsiao, Benjamin

    2011-03-01

    Crystallization changes of propylene-1-butylene (P-H) random copolymer with low butylene content (5.7 mol%) under uniaxial tensile deformation at high temperature (100& circ; C) was investigated using time-resolved wide- and small-angle X-ray scattering (WAXS/SAXS) techniques. Structure and preferred orientation at length scales of crystal unit cell and lamellae were investigated explicitly using 2D whole pattern analysis. γ -phase was found to be the dominant initial modification which was transformed into α -phase during stretching, forming more stable parallel packed polymer chains in the unit cell. 2D WAXS analysis enabled us to identify three orientation modes from different crystal forms, i.e., γ -phase with tilted cross- β configuration, α -phase with parallel chain packing and a-axis orientation of α -form crystals in daughter lamellae. 2D SAXS analysis based on stacking model enabled us to understand the development of the four-point pattern under deformation. We thank National Science Foundation for financial support and Derek W. Thurman and Andy H. Tsou from ExxonMobil company for providing copolymer samples.

  15. The migration of propylene glycol, mono-, di-, and triethylene glycols from regenerated cellulose film into food.

    PubMed

    Castle, L; Cloke, H R; Crews, C; Gilbert, J

    1988-11-01

    Chocolates, boiled sweets, toffees, cakes and meat pies were wrapped in regenerated cellulose films (with or without coatings) that contained various mixtures of glycol softeners and which had been specially formulated for particular food applications. Samples were unwrapped at intervals (up to the end of the usual maximum shelf-life for the food) and analysed for their glycol content. Analysis involved homogenization of the food in hot water, removal of fats with hexane, precipitation of sugars with calcium hydroxide and analysis of the glycols by capillary gas chromatography with flame ionization detection (GC/FID) after trimethylsilyl (TMS) derivatization. Triethylene glycol was analysed by selected ion monitoring GC/mass spectrometry (GC/MS) as interference problems occurred with the GC/FID approach. The results of the study showed that higher levels of migration occurred for propylene glycol than for triethylene glycol and the presence of a coating reduced the migration of both softeners. Generally, mono- and diethylene glycol levels in the food samples were below 10 mg/kg, although some samples wrapped in polyethylene glycol-softened films contained levels approaching the current statutory limit of 50 mg/kg. PMID:3206944

  16. Anticoagulant and antithrombotic activities of low-molecular-weight propylene glycol alginate sodium sulfate (PSS).

    PubMed

    Xin, Meng; Ren, Li; Sun, Yang; Li, Hai-hua; Guan, Hua-Shi; He, Xiao-Xi; Li, Chun-Xia

    2016-05-23

    Propylene glycol alginate sodium sulfate (PSS), a sulfated polysaccharide derivative, has been used as a heparinoid drug to prevent and treat hyperlipidemia and ischemic cardio-cerebrovascular diseases in China for nearly 30 years. To extend the applications of PSS, a series of low-molecular-weight PSSs (named FPs) were prepared by oxidative-reductive depolymerization, and the antithrombotic activities were investigated thoroughly in vitro and in vivo. The bioactivity evaluation demonstrated a positive correlation between the molecular weight and the anticoagulant and antithrombotic activities of FPs. FPs could prolong the APTT and clotting time and reduce platelet aggregation significantly. FPs could also effectively inhibit factor IIa in the presence of AT-III and HC-II. FPs decreased the wet weights and lengths of the thrombus and increased occlusion times in vivo. FP-6k, a PSS fragment with a molecular weight of 6 kDa, is an optimal antithrombotic candidate for further study and showed little chance for hemorrhagic action. PMID:26974373

  17. Novel vaginal drug delivery system: deformable propylene glycol liposomes-in-hydrogel.

    PubMed

    Vanić, Željka; Hurler, Julia; Ferderber, Kristina; Golja Gašparović, Petra; Škalko-Basnet, Nataša; Filipović-Grčić, Jelena

    2014-03-01

    Deformable propylene glycol-containing liposomes (DPGLs) incorporating metronidazole or clotrimazole were prepared and evaluated as an efficient drug delivery system to improve the treatment of vaginal microbial infections. The liposome formulations were optimized based on sufficient trapping efficiencies for both drugs and membrane elasticity as a prerequisite for successful permeability and therapy. An appropriate viscosity for vaginal administration was achieved by incorporating the liposomes into Carbopol hydrogel. DPGLs were able to penetrate through the hydrogel network more rapidly than conventional liposomes. In vitro studies of drug release from the liposomal hydrogel under conditions simulating human treatment confirmed sustained and diffusion-based drug release. Characterization of the rheological and textural properties of the DPGL-containing liposomal hydrogels demonstrated that the incorporation of DPGLs alone had no significant influence on mechanical properties of hydrogels compared to controls. These results support the great potential of DPGL-in-hydrogel as an efficient delivery system for the controlled and sustained release of antimicrobial drugs in the vagina. PMID:23931627

  18. Plasticization of poly(L-lactide) with poly(propylene glycol).

    PubMed

    Kulinski, Z; Piorkowska, E; Gadzinowska, K; Stasiak, M

    2006-07-01

    A new plasticizer for poly(L-lactide) (PLA)-poly(propylene glycol) (PPG) is proposed. The advantage of using PPG is that it does not crystallize, has low glass transition temperature, and is miscible with PLA. PLA was plasticized with PPGs with nominal Mw of 425 and 1000 g/mol. Poly(ethylene glycol) (PEG), long known as a plasticizer for PLA, with nominal Mw of 600 g/mol, was also used to plasticize PLA for comparison. The thermal and tensile properties of PLA and PLA with 5-12.5 wt % of the plasticizers were studied. In blends of PLA with PPGs the glass transition temperature was lower than that of neat PLA. Both PPGs enhanced the crystallizability of PLA albeit less than PEG. All of the plasticizers increased also the ability of PLA to plastic deformation which was reflected in a decrease of yield stress and in an increase of elongation at break. The effect was enhanced by the higher PPG content and also by lower molecular weight of PPG. A phase separation occurred only in the blend containing 12.5 wt % of PPG with higher molecular weight. The evidences of crazing were found in deformed samples of PLA with low plasticizer content, whereas the samples with higher content of plasticizers crystallized due to deformation. PMID:16827579

  19. Assessment of the dietary intake of propylene glycol in the Korean population.

    PubMed

    Lim, Ho Soo; Hwang, Ju Young; Choi, EunA; Lee, Gun Young; Yun, Sang Soon; Kang, TaeSeok

    2016-08-01

    An improved method for the analysis of propylene glycol (PG) in foods using a gas chromatography-flame ionisation detector (GC-FID), with confirmation by GC-MS, was validated by measuring several analytical parameters. The PG concentrations in 1073 products available in Korean markets were determined. PG was detected in 74.1% of the samples, in a concentration range from the limit of detection (n.d., 0.39 μg ml(-1)) to 12,819.9 mg kg(-1). The Korea National Health and Nutrition Examination Survey (KNHANES) 2011-2013 reported the mean intake levels of PG from all sources by the general population and consumers were 26.3 mg day(-1) (0.52 mg kg(-1) day(-1)) and 34.3 mg day(-1) (0.67 mg kg(-1) day(-1)), respectively. The 95th percentile intake levels of the general population and consumers were 123.6 mg day(-1) (2.39 mg kg(-1) day(-1)) and 146.3 mg day(-1) (2.86 mg kg(-1) day(-1)), respectively. In all groups of the general population, breads were the main contributors to the total PG intake. These reports provide a current perspective on the daily intake of PG in the Korean population. PMID:27389111

  20. The effect of materials selection on metals reduction in propylene glycol methyl ether acetate, PGMEA

    NASA Astrophysics Data System (ADS)

    Entezarian, Majid; Geiger, Bob

    2016-03-01

    The trend in microelectronics fabrication is to produce nano-features measuring down to 10 nm and finer. The PPT levels of organic and inorganic contaminants in the photoresist, solvent and cleaning solutions are becoming a major processing variable affecting the process capability and defectivity. The photoresist usually contains gels, metals, and particulates that could interfere with the lithography process and cause microbridging defects. Nano filters of 5 nm polypropylene, 5 nm polyethylene, and 10 nm natural nylon were used to filter propylene glycol methyl ether acetate PGMEA containing 50 ppb of Na, Mg, Al, Ca, Cr, Mn, Fe, Cu, Zn, and Pb. All filters were effective in removing trivalent Al, Cr, and Fe metals indicating the mechanism for their removal as mechanical sieving. However, the nylon was also very effective in removing the divalent metals showing adsorptive properties. Furthermore, the metal removal of the nylon membrane was studied as a function of surface chemistry. Natural and charged 40 nm nylon membranes were tested and found that charged nylon is more effective for metal removal.

  1. Synthesis of brominated acenaphthylenes and their flame-retardant effects on ethylene-propylene-diene terpolymer

    SciTech Connect

    Morita, Y.; Hagiwara, M.

    1982-09-01

    Bromoacenaphthylenes and their condensates as flame-retardant reagents were synthesized by bromination of acenaphthylene using ZnCl/sub 2/ - CF/sub 3/COOH or FeCl/sub 3/ as catalysts and subsequent dehydrobromination. The chief components were identified as bromoacenaphthylene monomers when ZnCl/sub 2/ - CF/sub 3/COOH were used, and as their condensates (mostly trimers) in the case of FeCl/sub 3/. Their performance as flame-retardant reagents for ethylene-propylene-diene terpolymer (EPDM) was evaluated by measuring the oxygen index of finished compounds, and flammability by a vertical flammability test based on UL-94-VO. Both the monomers and the condensates demonstrated high flame-retardant effectiveness. The high efficiency was attributed to their excellent dispersity in the base polymer and their characteristic thermal decomposition behavior. In thermal gravimetric analysis (TGA), they decomposed in a very wide range of temperature (ca.200-560/sup 0/C), which covers the decomposition range of EPDM. This was attributed to the existence of bromines of different thermal stabilities in one molecule. This paper is a part of a series of studies to develop new flame retardants which can give high flame retardancy as well as stabilty against ionizing radiation to EPDM.

  2. Fabrication and characteristic analysis of a poly(propylene fumarate) scaffold using micro-stereolithography technology.

    PubMed

    Lee, Jin Woo; Lan, Phung Xuan; Kim, Byung; Lim, Geunbae; Cho, Dong-Woo

    2008-10-01

    Scaffold fabrication for regenerating functional human tissues has an important role in tissue engineering, and there has been much progress in research on scaffold fabrication. However, current methods are limited by the mechanical properties of existing biodegradable materials and the irregular structures that they produce. Recently, several promising biodegradable materials have been introduced, including poly(propylene fumarate) (PPF). The development of micro-stereolithography allows the fabrication of free-form 3D microstructures as designed. Since this technology requires a low-viscosity resin to fabricate fine structures, we reduced the viscosity of PPF by adding diethyl fumarate. Using our system, the curing characteristics and material properties of the resin were analyzed experimentally. Then, we fabricated waffle shape and 3D scaffolds containing several hundred regular micro pores. This method controlled the pore size, porosity, interconnectivity, and pore distribution. The results show that micro-stereolithography has big advantages over conventional fabrication methods. In addition, the ultimate strength and elastic modulus of the fabricated scaffolds were measured, and cell adhesion to the fabricated scaffold was observed by growing seeded cells on it. These results showed that the PPF/DEF scaffold is a potential bone scaffold for tissue engineering. PMID:18335437

  3. [Determination of ethylene glycol in biological fluids--propylene glycol interferences].

    PubMed

    Gomółka, Ewa; Cudzich-Czop, Sylwia; Sulka, Adrianna

    2013-01-01

    Many laboratories in Poland do not use gas chromatography (GC) method for determination of ethylene glycol (EG) and methanol in blood of poisoned patients, they use non specific spectrophotometry methods. One of the interfering substances is propylene glycol (PG)--compound present in many medical and cosmetic products: drops, air freshens, disinfectants, electronic cigarettes and others. In Laboratory of Analytical Toxicology and Drug Monitoring in Krakow determination of EG is made by GC method. The method enables to distinguish and make resolution of (EG) and (PG) in biological samples. In the years 2011-2012 in several serum samples from diagnosed patients PG was present in concentration from several to higher than 100 mg/dL. The aim of the study was to estimate PG interferences of serum EG determination by spectrophotometry method. Serum samples containing PG and EG were used in the study. The samples were analyzed by two methods: GC and spectrophotometry. Results of serum samples spiked with PG with no EG analysed by spectrophotometry method were improper ("false positive"). The results were correlated to PG concentration in samples. Calculated cross-reactivity of PG in the method was 42%. Positive results of EG measured by spectrophotometry method must be confirmed by reference GC method. Spectrophotometry method shouldn't be used for diagnostics and monitoring of patients poisoned by EG. PMID:24466683

  4. Preparation, characterization and pharmacokinetics of fluorescence labeled propylene glycol alginate sodium sulfate

    NASA Astrophysics Data System (ADS)

    Li, Pengli; Li, Chunxia; Xue, Yiting; Zhang, Yang; Liu, Hongbing; Zhao, Xia; Yu, Guangli; Guan, Huashi

    2014-08-01

    A rapid and sensitive fluorescence labeling method was developed and validated for the microanalysis of a sulfated polysaccharide drug,namely propylene glycol alginate sodium sulfate (PSS), in rat plasma. Fluorescein isothiocyanate (FITC) was selected to label PSS, and 1, 6-diaminohexane was used to link PSS and FITC in order to prepare FITC-labeled PSS (F-PSS) through a reductive amination reaction. F-PSS was identified by UV-Vis, FT-IR and 1H-NMR spectrum. The cell stability and cytotoxicity of F-PSS were tested in Madin-Darby canine kidney (MDCK) cells. The results indicated that the labeling efficiency of F-PSS was 0.522% ± 0.0248% and the absolute bioavailability was 8.39%. F-PSS was stable in MDCK cells without obvious cytotoxicity. The method was sensitive and reliable; it showed a good linearity, precision, recovery and stability. The FITC labeling method can be applied to investigating the absorption and metabolism of PSS and other polysaccharides in biological samples.

  5. System Accommodation of Propylene Loop Heat Pipes For The Geoscience Laser Altimeter System (GLAS) Instrument

    NASA Technical Reports Server (NTRS)

    Grob, Eric W.; Powers, Edward I. (Technical Monitor)

    2001-01-01

    Loop Heat Pipes (LHP) are used for precise temperature control for NASA Goddard Space Flight Center's Geoscience Laser Altimeter System (GLAS) Instrument in a widely varying LEO thermal environment. Two propylene LHPs are utilized to provide separate thermal control for the Nd:YAG Lasers and the remaining avionics/detector components suite. Despite a rigorous engineering development and test plan to demonstrate the performance in the restrictive GLAS design, the flight units failed initial thermal vacuum acceptance testing at GSFC. Subsequent investigation revealed that compromises in the mechanical packaging of these systems resulted in inadequate charge levels for a concentric wick LHP. The redesign effort included larger compensation chambers that provide more fluid to the wick for start-up scenarios and highlighted the need to fully understand the limitations and accommodation requirements of new technologies in a system design application. Once again, seemingly minor departures from heritage configurations and limited resources led to performance and operational issues. This paper provides details into the GLAS LHP engineering development program and acceptance testing of the flight units, including the redesign effort.

  6. Hydrogenolysis of 6-carbon sugars and other organic compounds

    DOEpatents

    Werpy, Todd A.; Frye, Jr., John G.; Zacher, Alan H.; Miller, Dennis J.

    2005-01-11

    Methods for hydrogenolysis are described which use a Re-containing multimetallic catalyst for hydrogenolysis of both C--O and C--C bonds. Methods and compositions for reactions of hydrogen over a Re-containing catalyst with compositions containing a 6-carbon sugar, sugar alcohol, or glycerol are described. It has been surprisingly discovered that reaction with hydrogen over a Re-containing multimetallic catalyst resulted in superior conversion and selectivity to desired products such as propylene glycol.

  7. Effect of hypochlorite oxidation on cholinesterase-inhibition assay of acetonitrile extracts from fruits and vegetables for monitoring traces of organophosphate pesticides.

    PubMed

    Kitamura, Kentaro; Maruyama, Kaori; Hamano, Sachiko; Kishi, Tomohiro; Kawakami, Tsuyoshi; Takahashi, Yasuo; Onodera, Sukeo

    2014-02-01

    A reproducible method for monitoring traces of cholinesterase (ChE) inhibitors in acetonitrile extracts from fruits and vegetables is described. The method is based on hypochlorite oxidation and ChE inhibition assay. Four common representative samples of produce were selected from a supermarket to investigate the effect of different matrices on pesticides recoveries and assay precision. The samples were extracted with acetonitrile to prepare them for ChE inhibition assays: if necessary, clean-up was performed using dispersive solid-phase extraction for gas chromatography-mass spectrometry (GC/MS) analyses. Chlorine was tested as an oxidising reagent for the conversion of thiophosphorus pesticides (P=S compounds) into their P=O analogues, which have high ChE-inhibiting activity. Chlorine consumption of individual acetonitrile extracts was determined and was strongly dependent on the individual types of fruits and vegetables. After treating the acetonitrile extracts with an excess hypochlorite at 25°C for 15 min, the ChE-inhibiting activities and detection limits for each chlorine-treated pesticide solution were determined. Matrix composition did not interfere significantly with the determination of the pesticides. Enhanced anti-ChE activities leading to low detection limits (ppb levels) were observed for the chlorine-treated extracts that were spiked with chlorpyrifos, diazinon, fenitrothion, and isoxathion. This combination of oxidative derivatisation and ChE inhibition assays was used successfully to monitor and perform semi-quantitative determination of ChE inhibitors in apple, tomato, cucumber, and strawberry samples. PMID:24418711

  8. Study of the acetonitrile poisoning of platinum cathodes on proton exchange membrane fuel cell spatial performance using a segmented cell system

    NASA Astrophysics Data System (ADS)

    Reshetenko, Tatyana V.; St-Pierre, Jean

    2015-10-01

    Due to the wide applications of acetonitrile as a solvent in the chemical industry, acetonitrile can be present in the air and should be considered a possible pollutant. In this work, the spatial proton exchange membrane fuel cell performance exposed to air with 20 ppm CH3CN was studied using a segmented cell system. The injection of CH3CN led to performance losses of 380 mV at 0.2 A cm-2 and 290 mV at 1.0 A cm-2 accompanied by a significant change in the current density distribution. The observed local currents behavior is likely attributed to acetonitrile chemisorption and the subsequent two consecutive reduction/oxidation reactions. The hydrolysis of CH3CN and its intermediate imine species resulted in NH4+ formation, which increased the high-frequency resistance of the cell and affected oxygen reduction and performance. Other products of hydrolysis can be oxidized to CO2 under the operating conditions. The reintroduction of pure air completely recovered cell performance within 4 h at 1.0 A cm-2, while at 0.2 A cm-2 the cell recovery was only partial. A detailed analysis of the current density distribution, its correlation with spatial electrochemical impedance spectroscopy data, possible CH3CN oxidation/reduction mechanisms and mitigation strategies are presented and discussed.

  9. Origin of anomalous electronic circular dichroism spectrum of RuPt2(tppz)2Cl2(PF6)4 in acetonitrile.

    PubMed

    Yu, Hua-Gen

    2014-07-24

    We report a theoretical study of the structures, energetics, and electronic spectra of the Pt(II)/Ru(II) mixed-metal complex RuPt2(tppz)2Cl2(PF6)4 (tppz = 2,3,5,6-tetra(2-pyridyl)pyrazine) in acetonitrile. The hybrid B3LYP density functional theory and its TDDFT methods were used with a complete basis set (CBS) extrapolation scheme and a conductor polarizable continuum model (C-PCM) for solvation effects. Results showed that the trinuclear complex has four types of stable conformers and/or enantiomers. They are separated by high barriers owing to the repulsive H/H geometrical constraints in tppz. A strong entropy effect was found for the dissociation of RuPt2(tppz)2Cl2(PF6)n in acetonitrile. The UV-visible and emission spectra of the complex were also simulated. They are in good agreement with experiments. In this work we have largely focused on exploring the origin of anomalous electronic circular dichroism (ECD) spectra of the RuPt2(tppz)2Cl2(PF6)4 complex in acetonitrile. As a result, a new mechanism has been proposed together with a clear illustration by using a physical model. PMID:25026322

  10. Determination of strobilurin fungicides in cotton seed by combination of acetonitrile extraction and dispersive liquid-liquid microextraction coupled with gas chromatography.

    PubMed

    Xue, Jiaying; Li, Huichen; Liu, Fengmao; Jiang, Wenqing; Chen, Xiaochu

    2014-04-01

    The simultaneous determination of four strobilurin fungicides (picoxystrobin, kresoxim-methyl, trifloxystrobin, and azoxystrobin) in cotton seed by combining acetonitrile extraction and dispersive liquid-liquid microextraction was developed prior to GC with electron capture detection. Several factors, including the type and volume of the extraction and dispersive solvents, extraction condition and time, and salt addition, were optimized. The analytes were extracted with acetonitrile from cotton seed and the clean-up was carried out by primary secondary amine. Afterwards, 60 μL of n-hexane/toluene (1:1, v/v) with a lower density than water was mixed with 1 mL of the acetonitrile extract, then the mixture was injected into 7 mL of distilled water. A 0.1 mL pipette was used to collect a few microliters of n-hexane/toluene from the top of the aqueous solution. The enrichment factors of the analytes ranged from 36 to 67. The LODs were in the range of 0.1 × 10(-3) -2 × 10(-3) mg/kg. The relative recoveries varied from 87.7 to 95.2% with RSDs of 4.1-8.5% for the four fungicides. The good performance of the method, compared with the conventional pretreatments, has demonstrated it is suitable for determining low concentrations of strobilurin fungicide residues in cotton seed. PMID:24482392

  11. A novel strategy for acetonitrile wastewater treatment by using a recombinant bacterium with biofilm-forming and nitrile-degrading capability.

    PubMed

    Li, Chunyan; Yue, Zhenlei; Feng, Fengzhao; Xi, Chuanwu; Zang, Hailian; An, Xuejiao; Liu, Keran

    2016-10-01

    There is a great need for efficient acetonitrile removal technology in wastewater treatment to reduce the discharge of this pollutant in untreated wastewater. In this study, a nitrilase gene (nit) isolated from a nitrile-degrading bacterium (Rhodococcus rhodochrous BX2) was cloned and transformed into a biofilm-forming bacterium (Bacillus subtilis N4) that expressed the recombinant protein upon isopropylthio-β-galactoside (IPTG) induction. The recombinant bacterium (B. subtilis N4-pHT01-nit) formed strong biofilms and had nitrile-degrading capability. Further testing demonstrated that biofilms formed by B. subtilis N4-pHT01-nit were highly resistant to loading shock from acetonitrile and almost completely degraded the initial concentration of acetonitrile (800 mg L(-1)) within 24 h in a moving bed biofilm reactor (MBBR) after operation for 35 d. The bacterial composition of the biofilm, identified by high-throughput sequencing, in a reactor in which the B. subtilis N4-pHT01-nit bacterium was introduced indicated that the engineered bacterium was successfully immobilized in the reactor and became dominant genus. This work demonstrates that an engineered bacterium with nitrile-degrading and biofilm-forming capacity can improve the degradation of contaminants in wastewater. This approach offers a novel strategy for enhancing the biological oxidation of toxic pollutants in wastewater. PMID:27434252

  12. The distribution, fate, and effects of propylene glycol substances in the environment.

    PubMed

    West, Robert; Banton, Marcy; Hu, Jing; Klapacz, Joanna

    2014-01-01

    The propylene glycol substances comprise a homologous family of synthetic organic molecules that have widespread use and very high production volumes across the globe. The information presented and summarized here is intended to provide an overview of the most current and reliable information available for assessing the potential environmental exposures and impacts of these substances across the manufacture, use, and disposal phases of their product life cycles.The PG substances are characterized as being miscible in water, having very low octanol-water partition coefficients (log Pow) and exhibiting low potential to volatilize from water or soil in both pure and dissolved forms. The combination of these properties dictates that, almost regardless of the mode of their initial emission, they will ultimately associate with surface water, soil, and the related groundwater compartments in the environment. These substances have low affinity for soil and sediment particles, and thus will remain mobile and bio-available within these media.In the atmosphere, the PG substances are demonstrated to have short lifetimes(I. 7-11 h), due to rapid reaction with photochemically-generated hydroxyl radicals.This reactivity, combined with efficient wet deposition of their vapor and aerosol forms, lends to their very low potential for long-range transport via the atmosphere.In the aquatic and terrestrial compartments of the environment, the PG substances are rapidly and ultimately biodegraded under both aerobic and anaerobic conditions by a wide variety of microorganisms, regardless of prior adaptation to the substances.Except for the TePG substance, the propylene glycol substances meet the OECD definition of "readily biodegradable", and according to this definition are not expected to persist in either aquatic or terrestrial environments. The TePG exhibits inherent biodegradability, is not regarded to be persistent, and is expected to ultimately biodegrade in the environment, albeit

  13. A comparison of the electrochemical behavior of carbon aerogels and activated carbon fiber cloths

    SciTech Connect

    Tran, T.D.; Alviso, C.T.; Hulsey, S.S.; Nielsen, J.K.; Pekala, R.W.

    1996-05-10

    Electrochemical capacitative behavior of carbon aerogels and commercial carbon fiber cloths was studied in 5M KOH, 3M sulfuric acid, and 0.5M tetrethylammonium tetrafluoroborate/propylene carbonate electrolytes. The resorcinol-formaldehyde based carbon aerogels with a range of denisty (0.2-0.85 g/cc) have open-cell structures with ultrafine pore sizes (5-50 nm), high surface area (400-700 m{sup 2}/g), and a solid matrix composed of interconnected particles or fibers with characteristic diameters of 10 nm. The commercial fiber cloths in the density range 0.2-04g/cc have high surface areas (1000-2500 m{sup 2}/g). The volumetric capacitances of high-density aerogels are shown to be comparable to or exceeding those from activated carbon fibers. Electrochemical behavior of these materials in various electrolytes is compared and related to their physical properties.

  14. Fluorinated ethylene-propylene: a complementary alternative to PDMS for nanoimprint stamps

    NASA Astrophysics Data System (ADS)

    Greer, Andrew I. M.; Vasiev, Iskandar; Della-Rosa, Benoit; Gadegaard, Nikolaj

    2016-04-01

    Polydimethylsiloxane (PDMS) is used by many for nanoimprint applications due to its affordability, ease of preparation, mechanical flexibility, compatibility with imprint resists and transparency to UV light. However PDMS is notoriously flexible, tacky and permeable to air. Here fluorinated ethylene-propylene (FEP) is considered as a viable and versatile alternative material for nanoimprint stamps. FEP possesses many of the desirable nanoimprint attributes associated with PDMS but crucially also features a range of complementary characteristics, including an order of magnitude more mechanical strength allowing it to handle higher loads than PDMS, an intrinsically non-stick surface and is compatible with oxygen sensitive resists. Unlike elastomeric polymers, FEP is glassy so patterning may be realised via hot embossing. Not only is this a facile and rapid means of physical structuring but it also facilitates combinatorial patterning, providing a versatility beyond that of traditional casting materials. Due to the intrinsically slow creep of FEP both micro- and nanopatterning are successfully performed sequentially. Feature sizes from 45 nm were successfully realised via the hot-embossing method. To further demonstrate the potential of the material, a modified computer numerical control machine is used. It is capable of photo-, nanoimprint- and laser lithography in conjunction with patterned FEP foils. The tool is used to perform pattern transfer into a developmental nanoimprint resist from Micro Resist Technology, mr-NIL210 XP, and Nano SU-8 3005 negative tone photo resist from MicroChem. Ultimately three-tier lithography is performed in unison and advantageous step-and-repeat performance is achieved with fabricated FEP imprint stamps as they demould more compliantly and resist pressure and contamination better than PDMS.

  15. Degradable, antibiotic releasing poly(propylene fumarate)-based constructs for craniofacial space maintenance applications.

    PubMed

    Henslee, Allan M; Shah, Sarita R; Wong, Mark E; Mikos, Antonios G; Kasper, F Kurtis

    2015-04-01

    Space maintainers (SMs) used for craniofacial reconstruction function to preserve the void space created upon bone loss and promote soft tissue healing over the defect. Polymethylmethacrylate-based SMs present several drawbacks including implant exposure, secondary removal surgeries, and potential bacterial contamination during implantation. To address these issues, a novel composite material comprising poly(propylene fumarate) (PPF) with N-vinyl pyrrolidone (NVP) as the crosslinking agent, carboxymethylcellulose (CMC) hydrogel as a porogen, and antibiotic loaded poly(lactic-co-glycolic acid) (PLGA) microparticles as antibiotic carriers and porogen was fabricated. CMC was incorporated at 40 wt % to impart rapid porosity while PLGA microparticles were incorporated at 30 or 40 wt % to release either clindamycin or colistin. This study was designed to examine the effects of PPF:NVP ratio, PLGA wt %, and the drug dose on the mass loss, temporal porosity change and drug release kinetics of the composite construct. Mass loss decreased significantly in constructs containing 3:2 PPF:NVP ratio with 30 wt % PLGA (63.2 ± 0.8%) compared to the 2:3 PPF:NVP ratio (80.3 ± 1.0% and 85.3 ± 1.3% for 30 and 40 wt % PLGA content, respectively) at 8 weeks. In formulations with 3:2 PPF:NVP ratio, incorporation of 40 versus 30 wt % PLGA significantly increased the porosity at 8 weeks under accelerated degradation conditions. Constructs released clindamycin or colistin at concentrations above the minimum inhibitory concentration for target pathogens for 45 and 77 days, respectively. This study demonstrates that the composition of PPF/CMC/PLGA constructs can be modulated to achieve properties suitable for craniofacial degradable space maintenance applications. PMID:25046733

  16. Comparison of Ethylene Glycol and Propylene Glycol for the Vitrification of Immature Porcine Oocytes

    PubMed Central

    SOMFAI, Tamás; NAKAI, Michiko; TANIHARA, Fuminori; NOGUCHI, Junko; KANEKO, Hiroyuki; KASHIWAZAKI, Naomi; EGERSZEGI, István; NAGAI, Takashi; KIKUCHI, Kazuhiro

    2013-01-01

    Abstract Our aim was to optimize a cryoprotectant treatment for vitrification of immature porcine cumulus-oocyte complexes (COCs). Immature COCs were vitrified either in 35% ethylene glycol (EG), 35% propylene glycol (PG) or a combination of 17.5% EG and 17.5% PG. After warming, the COCs were in vitro matured (IVM), and surviving oocytes were in vitro fertilized (IVF) and cultured. The mean survival rate of vitrified oocytes in 35% PG (73.9%) was higher (P<0.05) than that in 35% EG (27.8%). Oocyte maturation rates did not differ among vitrified and non-vitrified control groups. Blastocyst formation in the vitrified EG group (10.8%) was higher (P<0.05) than that in the vitrified PG group (2.0%) but was lower than that in the control group (25.0%). Treatment of oocytes with 35% of each cryoprotectant without vitrification revealed a higher toxicity of PG on subsequent blastocyst development compared with EG. The combination of EG and PG resulted in 42.6% survival after vitrification. The maturation and fertilization rates of the surviving oocytes were similar in the vitrified, control and toxicity control (TC; treated with EG+PG combination without cooling) groups. Blastocyst development in the vitrified group was lower (P<0.05) than that in the control and TC groups, which in turn had similar development rates (10.7%, 18.1% and 23.3%, respectively). In conclusion, 35% PG enabled a higher oocyte survival rate after vitrification compared with 35% EG. However, PG was greatly toxic to oocytes. The combination of 17.5% EG and 17.5% PG yielded reasonable survival rates without toxic effects on embryo development. PMID:23666455

  17. Digital micromirror device (DMD)-based 3D printing of poly(propylene fumarate) scaffolds.

    PubMed

    Mott, Eric J; Busso, Mallory; Luo, Xinyi; Dolder, Courtney; Wang, Martha O; Fisher, John P; Dean, David

    2016-04-01

    Our recent investigations into the 3D printing of poly(propylene fumarate) (PPF), a linear polyester, using a DMD-based system brought us to a resin that used titanium dioxide (TiO2) as an ultraviolet (UV) filter for controlling cure depth. However, this material hindered the 3D printing process due to undesirable lateral or "dark" curing (i.e., in areas not exposed to light from the DMD chip). Well known from its use in sunscreen, another UV filter, oxybenzone, has previously been used in conjunction with TiO2. In this study we hypothesize that combining these two UV filters will result in a synergistic effect that controls cure depth and avoids dark cure. A resin mixture (i.e., polymer, initiator, UV filters) was identified that worked well. The resin was then further characterized through mechanical testing, cure testing, and cytotoxicity testing to investigate its use as a material for bone tissue engineering scaffolds. Results show that the final resin eliminated dark cure as shown through image analysis. Mechanically the new scaffolds proved to be far weaker than those printed from previous resins, with compressive strengths of 7.8 ± 0.5 MPa vs. 36.5 ± 1.6 MPa, respectively. The new scaffolds showed a 90% reduction in elastic modulus and a 74% increase in max strain. These properties may be useful in tissue engineering applications where resorption is required. Initial cytotoxicity evaluation was negative. As hypothesized, the use of TiO2 and oxybenzone showed synergistic effects in the 3D printing of PPF tissue engineering scaffolds. PMID:26838854

  18. Coacervation of β-conglycinin, glycinin and isoflavones induced by propylene glycol alginate in heated soymilk.

    PubMed

    Hsiao, Yu-Hsuan; Lu, Chun-Ping; Kuo, Meng-I; Hsieh, Jung-Feng

    2016-06-01

    This study investigated the propylene glycol alginate (PGA)-induced coacervation of β-conglycinin (7S), glycinin (11S) and isoflavones in heated soymilk. The addition of 0.9% PGA caused 7S, 11S, daidzein and genistein to coacervate following a 1h incubation period. SDS-PAGE showed that the protein bands corresponding to the 7S α', 7S α, 7S β, 11S A3, and 11S acidic subunits and the 11S basic proteins in the soymilk supernatant fraction (SSF) decreased to 37.7 ± 12.7%, 24.7 ± 3.9%, 4.9 ± 1.8%, 8.5 ± 2.7%, 18.1 ± 1.8% and 6.0 ± 1.6%, respectively. In addition, isoflavones including daidzein and genistein were also coacervated from the SSF into the soymilk pellet fraction (SPF) following incubation with 0.9% PGA for 1h. The amounts of daidzein and genistein in the SSF decreased to 8.6 ± 1.6% and 2.0 ± 1.0%, respectively. HPLC analysis suggested that daidzein and genistein were bound to the 7S and 11S proteins. These results suggested that daidzein and genistein were co-precipitated with the 7S and 11S proteins into the SPF by 0.9% PGA. Our results demonstrated that PGA is a potent coagulant for the coacervation of 7S, 11S, daidzein and genistein. PMID:26830560

  19. Sources of Propylene Glycol and Glycol Ethers in Air at Home

    PubMed Central

    Choi, Hyunok; Schmidbauer, Norbert; Spengler, John; Bornehag, Carl-Gustaf

    2010-01-01

    Propylene glycol and glycol ether (PGE) in indoor air have recently been associated with asthma and allergies as well as sensitization in children. In this follow-up report, sources of the PGEs in indoor air were investigated in 390 homes of pre-school age children in Sweden. Professional building inspectors examined each home for water damages, mold odour, building’s structural characteristics, indoor temperature, absolute humidity and air exchange rate. They also collected air and dust samples. The samples were analyzed for four groups of volatile organic compounds (VOCs) and semi-VOCs (SVOCs), including summed concentrations of 16 PGEs, 8 terpene hydrocarbons, 2 Texanols, and the phthalates n-butyl benzyl phthalate (BBzP), and di(2-ethylhexyl)phthalate (DEHP). Home cleaning with water and mop ≥ once/month, repainting ≥ one room prior to or following the child’s birth, and “newest” surface material in the child’s bedroom explained largest portion of total variability in PGE concentrations. High excess indoor humidity (g/m3) additionally contributed to a sustained PGE levels in indoor air far beyond several months following the paint application. No behavioral or building structural factors, except for water-based cleaning, predicted an elevated terpene level in air. No significant predictor of Texanols emerged from our analysis. Overall disparate sources and low correlations among the PGEs, terpenes, Texanols, and the phthalates further confirm the lack of confounding in the analysis reporting the associations of the PGE and the diagnoses of asthma, rhinitis, and eczema, respectively. PMID:21318004

  20. Poly(Propylene Fumarate) Reinforced Dicalcium Phosphate Dihydrate Cement Composites for Bone Tissue Engineering

    PubMed Central

    Alge, Daniel L.; Bennet, Jeffrey; Treasure, Trevor; Voytik-Harbin, Sherry; Goebel, W. Scott; Chu, Tien-Min Gabriel

    2012-01-01

    Calcium phosphate cements have many desirable properties for bone tissue engineering, including osteoconductivity, resorbability, and amenability to rapid prototyping based methods for scaffold fabrication. In this study, we show that dicalcium phosphate dihydrate (DCPD) cements, which are highly resorbable but also inherently weak and brittle, can be reinforced with poly(propylene fumarate) (PPF) to produce strong composites with mechanical properties suitable for bone tissue engineering. Characterization of DCPD-PPF composites revealed significant improvements in mechanical properties for cements with a 1.0 powder to liquid ratio. Compared to non-reinforced controls, flexural strength improved from 1.80 ± 0.19 MPa to 16.14 ± 1.70 MPa, flexural modulus increased from 1073.01 ± 158.40 MPa to 1303.91 ± 110.41 MPa, maximum displacement during testing increased from 0.11 ± 0.04 mm to 0.51 ± 0.09 mm, and work of fracture improved from 2.74 ± 0.78 J/m2 to 249.21 ± 81.64 J/m2. To demonstrate the utility of our approach for scaffold fabrication, 3D macroporous scaffolds were prepared with rapid prototyping technology. Compressive testing revealed that PPF reinforcement increased scaffold strength from 0.31 ± 0.06 MPa to 7.48 ± 0.77 MPa. Finally, 3D PPF-DCPD scaffolds were implanted into calvarial defects in rabbits for 6 weeks. Although the addition of mesenchymal stem cells to the scaffolds did not significantly improve the extent of regeneration, numerous bone nodules with active osteoblasts were observed within the scaffold pores, especially in the peripheral regions. Overall, the results of this study suggest that PPF-DCPD composites may be promising scaffold materials for bone tissue engineering. PMID:22489012

  1. Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

    PubMed Central

    NATU, Vaishali Prakash; DUBEY, Nileshkumar; LOKE, Gerald Choon Leong; Teng Seng, TAN; Wee Hsuan, NG; YONG, Chee Weng; Tong, CAO; ROSA, Vinicius

    2015-01-01

    Objective To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water. Material and Methods White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey’s post-hoc analysis (a=0.05). Results The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0. Conclusion Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA. PMID:26398513

  2. Regional brain uptake and retention of Tc-99m-propylene amine oxime derivatives

    SciTech Connect

    Chaplin, S.B.; Oberle, P.O.; Hoffman, T.J.; Volkert, W.A.; Holmes, R.A.; Nowotnik, D.P.; Pickett, R.D.; Neirinckx, R.

    1985-05-01

    Tc-99m-propylene amine oxime (Tc-99m-PnAO) is a neutral lipophilic chelate that rapidly and passively enters the cerebral cortex (80% on first pass in baboon brain) and then clears exponentially leaving inadequate activity to perform conventional SPECT brain imaging. When side chains are attached to the PnAO backbone lipophilicity is increased, as well as brain retention. In this work the authors evaluated regional brain uptake and retention of Tc-99m-PnAO and several of its derivatives in rat brain using serial autoradiography (ARG). Autoradiographs of each Tc-99m chelate at 5 sec. post peak brain uptake demonstrate discrete grey to white matter differentiation. White matter tracts are well delineated and the darker areas of grey matter appearing in the midbrain and thalamus, corresponding to areas of high capillary density and high blood flow documented with C-14-iodoantipyrine, are easily distinguished. Within 5 min. of the peak uptake the regional uptake and grey/white differentiation is lost on the Tc-99m-PnAO ARG. In contrast the 5 min. ARG of the more lipophilic Tc-99m, chelate with dimethyl-PnAO (DMPnAO) shows the complete reverse of the 5 sec. ARG, with greater activity in the white matter tracts than in the grey matter. One of the derivatives, tetramethyl-PAO (TMPAO) complexed with Tc-99m is retained in the grey matter of rat brain and shows persistent grey to white localization for at least 60 min., analogous to what has been reported with I-123-IMP. These results suggest that Tc-99m-TMPAO or one of its derivatives may be appropriate for SPECT imaging of cerebral blood flow abnormalities.

  3. Fluorinated ethylene-propylene: a complementary alternative to PDMS for nanoimprint stamps.

    PubMed

    Greer, Andrew I M; Vasiev, Iskandar; Della-Rosa, Benoit; Gadegaard, Nikolaj

    2016-04-15

    Polydimethylsiloxane (PDMS) is used by many for nanoimprint applications due to its affordability, ease of preparation, mechanical flexibility, compatibility with imprint resists and transparency to UV light. However PDMS is notoriously flexible, tacky and permeable to air. Here fluorinated ethylene-propylene (FEP) is considered as a viable and versatile alternative material for nanoimprint stamps. FEP possesses many of the desirable nanoimprint attributes associated with PDMS but crucially also features a range of complementary characteristics, including an order of magnitude more mechanical strength allowing it to handle higher loads than PDMS, an intrinsically non-stick surface and is compatible with oxygen sensitive resists. Unlike elastomeric polymers, FEP is glassy so patterning may be realised via hot embossing. Not only is this a facile and rapid means of physical structuring but it also facilitates combinatorial patterning, providing a versatility beyond that of traditional casting materials. Due to the intrinsically slow creep of FEP both micro- and nanopatterning are successfully performed sequentially. Feature sizes from 45 nm were successfully realised via the hot-embossing method. To further demonstrate the potential of the material, a modified computer numerical control machine is used. It is capable of photo-, nanoimprint- and laser lithography in conjunction with patterned FEP foils. The tool is used to perform pattern transfer into a developmental nanoimprint resist from Micro Resist Technology, mr-NIL210 XP, and Nano SU-8 3005 negative tone photo resist from MicroChem. Ultimately three-tier lithography is performed in unison and advantageous step-and-repeat performance is achieved with fabricated FEP imprint stamps as they demould more compliantly and resist pressure and contamination better than PDMS. PMID:26938810

  4. High-yield synthesis of few-layer graphene flakes through electrochemical expansion of graphite in propylene carbonate electrolyte.

    PubMed

    Wang, Junzhong; Manga, Kiran Kumar; Bao, Qiaoliang; Loh, Kian Ping

    2011-06-15

    High-yield production of few-layer graphene flakes from graphite is important for the scalable synthesis and industrial application of graphene. However, high-yield exfoliation of graphite to form graphene sheets without using any oxidation process or super-strong acid is challenging. Here we demonstrate a solution route inspired by the lithium rechargeable battery for the high-yield (>70%) exfoliation of graphite into highly conductive few-layer graphene flakes (average thickness <5 layers). A negative graphite electrode can be electrochemically charged and expanded in an electrolyte of Li salts and organic solvents under high current density and exfoliated efficiently into few-layer graphene sheets with the aid of sonication. The dispersible graphene can be ink-brushed to form highly conformal coatings of conductive films (15 ohm/square at a graphene loading of <1 mg/cm(2)) on commercial paper. PMID:21557613

  5. The charge and discharge behavior of molybdenum trioxide electrodes in lithium perchlorate-propylene carbonate electrolyte. Technical report

    SciTech Connect

    Hunger, H.F.; Ellison, J.E.

    1980-07-01

    The anodic and cathodic behavior of molybdenum trioxide electrodes in various states of lithiation was investigated in 1M LiClO/sub 4/-PC electrolytes at room temperature. A comparison was made between the anodic and cathodic rate capabilities of the electrodes. From cycling experiments at various depths of discharge, cycle life data were obtained. Problems observed after deep discharges are discussed.

  6. Effect of calcium phosphate coating and rhBMP-2 on bone regeneration in rabbit calvaria using poly(propylene fumarate) scaffolds.

    PubMed

    Dadsetan, Mahrokh; Guda, Teja; Runge, M Brett; Mijares, Dindo; LeGeros, Racquel Z; LeGeros, John P; Silliman, David T; Lu, Lichun; Wenke, Joseph C; Brown Baer, Pamela R; Yaszemski, Michael J

    2015-05-01

    Various calcium phosphate based coatings have been evaluated for better bony integration of metallic implants and are currently being investigated to improve the surface bioactivity of polymeric scaffolds. The aim of this study was to evaluate the role of calcium phosphate coating and simultaneous delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2) on the in vivo bone regeneration capacity of biodegradable, porous poly(propylene fumarate) (PPF) scaffolds. PPF scaffolds were coated with three different calcium phosphate formulations: magnesium-substituted β-tricalcium phosphate (β-TCMP), carbonated hydroxyapatite (synthetic bone mineral, SBM) and biphasic calcium phosphate (BCP). In vivo bone regeneration was evaluated by implantation of scaffolds in a critical-sized rabbit calvarial defect loaded with different doses of rhBMP-2. Our data demonstrated that scaffolds with each of the calcium phosphate coatings were capable of sustaining rhBMP-2 release and retained an open porous structure. After 6weeks of implantation, micro-computed tomography revealed that the rhBMP-2 dose had a significant effect on bone formation within the scaffolds and that the SBM-coated scaffolds regenerated significantly greater bone than BCP-coated scaffolds. Mechanical testing of the defects also indicated restoration of strength in the SBM and β-TCMP with rhBMP-2 delivery. Histology results demonstrated bone growth immediately adjacent to the scaffold surface, indicating good osteointegration and osteoconductivity for coated scaffolds. The results obtained in this study suggest that the coated scaffold platform demonstrated a synergistic effect between calcium phosphate coatings and rhBMP-2 delivery and may provide a promising platform for the functional restoration of large bone defects. PMID:25575855

  7. Infrared Spectra of Water Bending Bands of Propylene Oxide-Water Complexes: Sequential Solvation of a Chiral Molecule in Water

    NASA Astrophysics Data System (ADS)

    Liu, Xunchen; Xu, Yunjie

    2011-06-01

    Sequential solvation of propylene oxide (C3H6O), an prototypical chiral molecule, with water has been investigated using high resolution infrared spectroscopy and ab initio methods. In a number of low resolution studies, the vibrational and vibrational circular dichroism spectral features at the water bending vibration region had been shown to be highly sensitive to the water solvation structures around propylene oxide in aqueous solution. The current study aims to provide quantitative information about solvation of a chiral molecule with water molecules at the molecular level and to provide the experimental benchmarks for calculations of vibrational frequencies in these larger molecular complexes. The high resolution infrared spectra of the propylene oxide-water complexes have been measured using a pulsed jet infrared spectrometer equipped with a room temperature external cavity quantum cascade laser and an astigmatic multi-pass cell. At least 6 bands have been observed from 1650 to 1680 Cm-1. Based on the previous microwave spectroscopic studies, these bands have been assigned to the blue-shifted water bending (ν_2) vibration modes associated with both the syn- and anti- conformers of the binary (C3H6O-H2O) and ternary (C3H6O-(H2O)2) complexes. This report shows the power of high resolution infrared spectroscopy to study multi-conformers of relatively large organic molecule complexes produced in a jet expansion. M. Losada, P. Nguyen, and Y .Xu, J. Phys. Chem. A, 112, 5621, (2008) Z. Su, Q. Wen, and Y. Xu, J. Am. Chem. Soc., 128, 6755, (2006) Z. Su and Y. Xu, Angew. Chem. Int. Ed., 46, 6163, (2007)

  8. DEVELOPMENT OF A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR PROPYLENE GLYCOL MONOMETHYL ETHER AND ITS ACETATE IN RATS AND HUMANS

    SciTech Connect

    Corley, Rick A.; Gies, Richard A.; Wu, Hong; Weitz, Karl K.

    2005-03-05

    Propylene glycol monomethyl ether (PM), along with its acetate, is the most widely used of the propylene glycol ether family of solvents. The most common toxic effects of PM observed in animal studies include sedation, very slight alpha2u globulin-mediated nephropathy (male rats only) and hepatomegally at high exposures (typically >1000 ppm). Sedation in animal studies usually resolves within a few exposures to 3000 ppm (the highest concentration used in subchronic and chronic inhalation studies) due to the induction of metabolizing enzymes. Data from a variety of pharmacokinetic and mechanistic studies have been incorporated into a PBPK model for PM and its acetate in rats and mice. Published controlled exposure and workplace biomonitoring studies have also been included for comparisons of the internal dosimetry of PM and its acetate between laboratory animals and humans. PM acetate is rapidly hydrolyzed to PM, which is further metabolized to either glucuronide or sulphate conjugates (minor pathways) or propylene glycol (major pathway). In vitro half-lives for PM acetate range from 14-36 min depending upon the tissue and species. In vivo half-lives are considerably faster, reflecting the total contributions of esterases in the blood and tissues of the body, and are on the order of just a few minutes. Thus, very little PM acetate is found in vivo and, other than potential portal of entry irritation, the toxicity of PM acetate is related to PM. Regardless of the source for PM (either PM or its acetate), rats were predicted to have a higher Cmax and AUC for PM in blood than humans, especially at concentrations greater than the current ACGIH TLV of 100 ppm. This would indicate that the major systemic effects of PM would be expected to be less severe in humans than rats at comparable inhalation exposures.

  9. Venting of a Water/Inhibited Propylene Glycol Mixture in a Vacuum Environment-Characterization and Representative Test Results

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Erickson, Lisa R.

    2011-01-01

    A planned use of the Orion space vehicle involves its residence at the International Space Station for six months at a time. One concept of operations involves temporarily venting portions of the idle Orion active thermal control system (ATCS) during the docked phase, preventing freezing. The venting would have to be reasonably complete with few, if any, completely filled pockets of frozen liquid. Even if pockets of frozen liquid did not damage the hardware during the freezing process, they could prevent the system from filling completely prior to its reactivation. The venting of single component systems in a space environment has been performed numerous times and is well understood. Local nucleation occurs at warm, relatively massive parts of the system, which creates vapor and forces the bulk liquid out of the system. The remnants of the liquid will freeze, then evaporate over time through local heating. Because the Orion ATCS working fluid is a 50/50 mixture of water and inhibited propylene glycol, its boiling behavior was expected to differ from that of a pure fluid. It was thought that the relatively high vapor pressure water might evaporate preferentially, leaving behind a mixture enriched with the low vapor pressure propylene glycol, which would be vaporization ]resistant. Owing to this concern, a test was developed to compare the evaporation behavior of pure water, a 50/50 mixture of water and inhibited propylene glycol, and inhibited propylene glycol. The test was performed using room temperature fluids in an instrumented thin walled stainless steel vertical tube. The 1 in x 0.035 in wall tube was instrumented with surface thermocouples and encased in closed cell polyurethane foam. Reticulated polyurethane foam was placed inside the tube to reduce the convection currents. A vacuum system connected to the top of the tube set the pressure boundary condition. Tests were run for the three fluids at back pressures ranging from 1 to 18 torr. During each test

  10. Propylene glycol-embodying deformable liposomes as a novel drug delivery carrier for vaginal fibrauretine delivery applications.

    PubMed

    Li, Wei-Ze; Hao, Xu-Liang; Zhao, Ning; Han, Wen-Xia; Zhai, Xi-Feng; Zhao, Qian; Wang, Yu-E; Zhou, Yong-Qiang; Cheng, Yu-Chuan; Yue, Yong-Hua; Fu, Li-Na; Zhou, Ji-Lei; Wu, Hong-Yu; Dong, Chun-Jing

    2016-03-28

    The purpose of this work was to develop and characterize the fibrauretine (FN) loaded propylene glycol-embodying deformable liposomes (FDL), and evaluate the pharmacokinetic behavior and safety of FDL for vaginal drug delivery applications. FDL was characterized for structure, particle size, zeta potential, deformability and encapsulation efficiency; the ability of FDL to deliver FN across vagina tissue in vitro and the distribution behavior of FN in rat by vaginal drug delivery were investigated, the safety of FDL to the vagina of rabbits and rats as well as human vaginal epithelial cells (VK2/E6E7) were also evaluated. Results revealed that: (i) the FDL have a closed spherical shape and lamellar structure with a homogeneous size of 185±19nm, and exhibited a negative charge of -53±2.7mV, FDL also have a good flexibility with a deformability of 92±5.6 (%phospholipids/min); (ii) the dissolving capacity of inner water phase and hydrophilicity of phospholipid bilayers of deformable liposomes were increased by the presence of propylene glycol, this may be elucidated by the fluorescent probes both lipophilic Nile red and hydrophilic calcein that were filled up the entire volume of the FDL uniformly, so the FDL with a high entrapment capacity (were calculated as percentages of total drug) for FN was 78±2.14%; (iii) the permeability of FN through vaginal mucosa was obviously improved by propylene glycol-embodying deformable liposomes, no matter whether the FN loaded in liposomes or not, although FN loaded in liposomes caused the highest permeability and drug reservoir in vagina; (iv) the FN mainly aggregated in the vagina and uterus, then the blood, spleen, liver, kidney, heart and lungs for vaginal drug delivery, this indicating vaginal delivery of FDL have a better 'vaginal local targeting effect'; and (v) the results of safety evaluation illustrate that the FDL is non-irritant and well tolerated in vivo, thereby establishing its vaginal drug delivery potential

  11. Phototocatalytic Lithography of Poly(Propylene Sulfide) Block Copolymers: Towards High Throughput Nanolithography for Biomolecular Arraying Applications

    PubMed Central

    Stone, Gary; Hiddessen, Amy L.; Dugan, Lawrence C.; Wu, Ligang; Hailey, Philip; Conway, James W.; Kuenzler, Tobias; Feller, Lydia; Cerritelli, Simona; Hubbell, Jeffrey A.

    2009-01-01

    Photocatalytic lithography (PCL) is an inexpensive, fast and robust method of oxidizing surface chemical moieties to produce patterned substrates. This technique has utility in basic biological research, as well as various biochip applications. We report on porphyrin-based PCL for patterning poly(propylene sulfide) block copolymer films on gold substrates at the micron and sub-micron scale. We confirm chemical patterning with imaging ToF-SIMS and low voltage SEM. Biomolecular patterning on micron and submicron scales is demonstrated with proteins, protein-linked beads and fluorescently labeled proteins. PMID:19113808

  12. Comparison of type A and C Fluorinated Ethylene Propylene (FEP) as cover materials for silicon solar cells

    NASA Technical Reports Server (NTRS)

    Broder, J. D.

    1976-01-01

    Fluorinated ethylene propylene film (FEP, 0.0127 cm thick) was heat and pressure laminated to silicon solar cells as a low cost substitute for quartz covers. The FEP-C, treated on one side for bonding, was compared to FEP-A, an untreated FEP. With FEP-A, a silane adhesion promoter was applied to the cells. The FEP-C covers delaminated during accelerated temperature-humidity testing and Earth environmental exposure testing; FEP-A covers were unchanged. No differences were observed in peel tests, but FEP-A is superior in its resistance to tearing and in retention of transmission properties after exposure to ultraviolet radiation.

  13. Small-Scale Mechanical Characterization of Space-Exposed Fluorinated Ethylene Propylene Recovered from the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Jones, J. S.; Sharon, J. A.; Mohammed, J.; Hemker, K. J.

    2012-01-01

    Multi-layer insulation panels from the Hubble Space Telescope have been recovered after 19.1 years of on-orbit service and micro-tensile experiments have been performed to characterize the effect of space exposure on the mechanical response of the outermost layer. This outer layer, 127 m thick fluorinated ethylene propylene with a 100 nm thick vapor deposited aluminum reflective coating, maintained significant tensile ductility but exhibited a degradation of strength that scales with severity of space exposure. This change in properties is attributed to damage from incident solar flux, atomic oxygen damage, and thermal cycling.

  14. catena-Poly[[tris­(acetonitrile-κN)praseodymium(III)]tris­(μ-trifluoro­methane­sulfonato-κ2 O:O′)

    PubMed Central

    Apostolidis, Christos; Walter, Olaf

    2013-01-01

    In the colourless title compound, [Pr(CF3O3S)3(CH3CN)3]n, the three trifluoro­methane­sulfonate anions form three bridges via O:O′-coordination between two PrIII atoms. The structure contains [Pr(NCMe)3-μ2(OTf)3—Pr(NCMe)3-μ2(OTf)3]n (NCMe is acetonitrile; OTf is trifluoromethanesulfonate) chains parallel to the a axis. The PrIII atom is nine-coordinate in a distorted tricapped trigonal-prismatic environment. PMID:23476322

  15. Oxygen transfer from an intramolecularly coordinated diaryltellurium oxide to acetonitrile. Formation and combined AIM and ELI-D analysis of a novel diaryltellurium acetimidate.

    PubMed

    Mallow, Ole; Bolsinger, Jens; Finke, Pamela; Hesse, Malte; Chen, Yu-Sheng; Duthie, Andrew; Grabowsky, Simon; Luger, Peter; Mebs, Stefan; Beckmann, Jens

    2014-08-01

    The reaction of the intramolecularly coordinated diaryltellurium(IV) oxide (8-Me2NC10H6)2TeO with acetonitrile proceeds with oxygen transfer and gives rise to the formation of the novel zwitterionic diaryltelluronium(IV) acetimidate (8-Me2NC10H6)2TeNC(O)CH3 (1) in 57% yield. Hydrolysis of 1 with hydrochloric acid affords acetamide and the previously known diarylhydroxytelluronium(IV) chloride [(8-Me2NC10H6)2Te(OH)]Cl. PMID:25026100

  16. An economic analysis of hyperketonemia testing and propylene glycol treatment strategies in early lactation dairy cattle.

    PubMed

    McArt, J A A; Nydam, D V; Oetzel, G R; Guard, C L

    2014-11-01

    The purpose was to develop stochastic economic models which address variation in disease risks and costs in order to evaluate different simulated on-farm testing and propylene glycol (PG) treatment strategies based on herd hyperketonemia (HYK) incidence during the first 30 DIM. Data used in model development concerning the difference in health and production consequences between HYK and non-ketotic cows were based on results from 10 studies representing over 13,000 cows from 833 dairy farms in North America, Canada, and Europe. Inputs for PG associated variables were based on a large field trial using cows from 4 free-stall dairy herds (2 in New York and 2 in Wisconsin). Four simulated on-farm testing and treatment strategies were analyzed at herd HYK incidences ranging from 5% to 80% and included: 1) treating all cows with 5d of PG starting at 5 DIM, 2) testing all cows for HYK 1 day per week (e.g. Mondays) from 3 to 16 DIM and treating all positive cows with 5d of oral PG, 3) testing all cows for HYK 2 days per week (e.g. Mondays and Thursdays) from 3 to 9 DIM and treating all positive cows with 5d of oral PG, and 4) testing all cows for HYK 3 days per week (e.g. Mondays, Wednesdays, and Fridays) from 3 to 16 DIM and treating all positive cows with 5d of oral PG. Cost-benefit analysis included the costs associated with labor to test cows, β-hydroxybutyrate test strips, labor to treat cows, PG, and the associated gain in milk production, decrease in DA and early removal risks of PG treated HYK positive cows compared to non-treated HYK positive cows. Stochastic models were developed to account for variability in the distribution of input variables. Per 100 fresh cows in a herd with an HYK incidence of 40%, the mean economic benefits of the 4 different strategies were $1088, $744, $1166, and $760, respectively. Testing cows 2 days per week from 3 to 9 DIM was the most cost-effective strategy for herds with HYK incidences between 15% and 50%; above 50%, treating all

  17. In vitro study of a new biodegradable nanocomposite based on poly propylene fumarate as bone glue.

    PubMed

    Shahbazi, S; Moztarzadeh, F; Sadeghi, G Mir Mohamad; Jafari, Y

    2016-12-01

    A novel poly propylene fumarate (PPF)-based glue which is reinforced by nanobioactive glass (NBG) particles and promoted by hydroxyethyl methacrylate (HEMA) as crosslinker agent, was developed and investigated for bone-to-bone bonding applications. In-vitro bioactivity, biodegradability, biocompatibility, and bone adhesion were tested and the results have verified that it can be used as bone glue. In an in-vitro condition, the prepared nanocomposite (PPF/HEMA/NBG) showed improved adhesion to wet bone surfaces. The combined tension and shear resistance between two wet bone surfaces was measured, and its maximum value was 9±59MPa. To investigate the bioactivity and biodegradability of the nanocomposite, it has been immersed in simulated body fluid (SBF). After 14days exposure to SBF, a hydroxyapatite (HA) layer formed on the surface of the composite confirms the bioactivity of this material. In the XRD pattern of the nanocomposite surface, the HA characteristic diffraction peak at θ=26 and 31.8 were observed. Also, by monitoring the weight change after 8weeks immersion in SBF, the mass loss was about 16.46wt%. It has been confirmed that this nanocomposite is a biodegradable material. Also, bioactivity and biodegradability of nanocomposite have been proved by SEM images. It has been showed that by using NBG particles and HEMA precursor, mechanical properties increased significantly. The ultimate tensile strength (UTS) of nanocomposite which contains 20% NBG and the ratio of 70/30wt% PPF/HEMA (PHB.732) was approximately 62MPa, while the UTS in the pure PPF/HEMA was about 32MPa. High cell viability in this nanocomposite (MTT assays, 85-95%) can be attributed to the NBG nature which contains calcium phosphate and is similar to physiological environment. Furthermore, it possesses biomineralization and biodegradation which significantly affected by impregnation of hydrophilic HEMA in the PPF-based polymeric matrix. The results indicated that the new synthesized

  18. Reductions of oxygen, carbon dioxide, and acetonitrile by the magnesium(II)/magnesium(I) couple in aqueous media: theoretical insights from a nano-sized water droplet.

    PubMed

    Lam, Tim-Wai; Zhang, Han; Siu, Chi-Kit

    2015-03-26

    Reductions of O2, CO2, and CH3CN by the half-reaction of the Mg(II)/Mg(I) couple (Mg(2+) + e(-) → Mg(+•)) confined in a nanosized water droplet ([Mg(H2O)16](•+)) have been examined theoretically by means of density functional theory based molecular dynamics methods. The present works have revealed many intriguing aspects of the reaction dynamics of the water clusters within several picoseconds or even in subpicoseconds. The reduction of O2 requires an overall doublet spin state of the system. The reductions of CO2 and CH3CN are facilitated by their bending vibrations and the electron-transfer processes complete within 0.5 ps. For all reactions studied, the radical anions, i.e., O2(•-), CO2(•-), and CH3CN(•-), are initially formed on the cluster surface. O2(•-) and CO2(•-) can integrate into the clusters due to their high hydrophilicity. They are either solvated in the second solvation shell of Mg(2+) as a solvent-separated ion pair (ssip) or directly coordinated to Mg(2+) as a contact-ion pair (cip) having the (1)η-[MgO2](•+) and (1)η-[MgOCO](•+) coordination modes. The (1)η-[MgO2](•+) core is more crowded than the (1)η-[MgOCO](•+) core. The reaction enthalpies of the formation of ssip and cip of [Mg(CO2)(H2O)16](•+) are -36 ± 4 kJ mol(-1) and -30 ± 9 kJ mol(-1), respectively, which were estimated based on the average temperature changes during the ion-molecule reaction between CO2 and [Mg(H2O)16](•+). The values for the formation of ssip and cip of [Mg(O2)(H2O)16](•+) are estimated to be -112 ± 18 kJ mol(-1) and -128 ± 28 kJ mol(-1), respectively. CH3CN(•-) undergoes protonation spontaneously to form the hydrophobic [CH3CN, H](•). Both CH3CN and [CH3CN, H](•) cannot efficiently penetrate into the clusters with activation barriers of 22 kJ mol(-1) and ∼40 kJ mol(-1), respectively. These results provide fundamental insights into the solvation dynamics of the Mg(2+)/Mg(•+) couple on the molecular level. PMID:25738586

  19. Confocal Raman microscopy and multivariate statistical analysis for determination of different penetration abilities of caffeine and propylene glycol applied simultaneously in a mixture on porcine skin ex vivo.

    PubMed

    Mujica Ascencio, Saul; Choe, ChunSik; Meinke, Martina C; Müller, Rainer H; Maksimov, George V; Wigger-Alberti, Walter; Lademann, Juergen; Darvin, Maxim E

    2016-07-01

    Propylene glycol is one of the known substances added in cosmetic formulations as a penetration enhancer. Recently, nanocrystals have been employed also to increase the skin penetration of active components. Caffeine is a component with many applications and its penetration into the epidermis is controversially discussed in the literature. In the present study, the penetration ability of two components - caffeine nanocrystals and propylene glycol, applied topically on porcine ear skin in the form of a gel, was investigated ex vivo using two confocal Raman microscopes operated at different excitation wavelengths (785nm and 633nm). Several depth profiles were acquired in the fingerprint region and different spectral ranges, i.e., 526-600cm(-1) and 810-880cm(-1) were chosen for independent analysis of caffeine and propylene glycol penetration into the skin, respectively. Multivariate statistical methods such as principal component analysis (PCA) and linear discriminant analysis (LDA) combined with Student's t-test were employed to calculate the maximum penetration depths of each substance (caffeine and propylene glycol). The results show that propylene glycol penetrates significantly deeper than caffeine (20.7-22.0μm versus 12.3-13.0μm) without any penetration enhancement effect on caffeine. The results confirm that different substances, even if applied onto the skin as a mixture, can penetrate differently. The penetration depths of caffeine and propylene glycol obtained using two different confocal Raman microscopes are comparable showing that both types of microscopes are well suited for such investigations and that multivariate statistical PCA-LDA methods combined with Student's t-test are very useful for analyzing the penetration of different substances into the skin. PMID:27108784

  20. Studies on Poly(propylene fumarate-co-caprolactone diol) Thermoset Composites towards the Development of Biodegradable Bone Fixation Devices

    PubMed Central

    Jayabalan, M.

    2009-01-01

    The effect of reinforcement in the cross-linked poly(propylene fumarate-co-caprolactone diol) thermoset composites based on Kevlar fibres and hydroxyapatite was studied. Cross-linked poly(propylene fumarate-co-caprolactone diol) was also studied without any reinforcement for comparison. The reinforcing fibre acts as a barrier for the curing reaction leading to longer setting time and lesser cross-link density. The fibre and HA reinforced composites have almost the same compressive strength. Nonreinforced material undergoes greater degree of swelling. Among the reinforced materials, the hydroxyapatite reinforced composite has a much higher swelling percentage than the fibre reinforced one. The studies on in vitro degradation of the cured materials reveal hydrolytic degradation in Ringer's solution and PBS medium during aging. All the three materials are found to swell initially in Ringer's solution and PBS medium during aging and then undergo gradual degradation. Compression properties of these cross-linked composites increase with aging; HA reinforced composite has the highest compressive strength and compressive modulus, whereas the aged fibre-reinforced composite has the least compressive strength and modulus. PMID:20126578