Science.gov

Sample records for alcohols ethers esters

  1. Equilibrium 2H/ 1H fractionations in organic molecules. II: Linear alkanes, alkenes, ketones, carboxylic acids, esters, alcohols and ethers

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Sessions, Alex L.; Nielsen, Robert J.; Goddard, William A., III

    2009-12-01

    Equilibrium 2H/ 1H fractionation factors (α eq) for various H positions in alkanes, alkenes, ketones, carboxylic acids, esters, alcohols, and ethers were calculated between 0 and 100 °C using vibrational frequencies from ab initio QM calculations (B3LYP/6-311G**). Results were then corrected using a temperature-dependent linear calibration curve based on experimental data for H α in ketones ( Wang et al., 2009). The total uncertainty in reported α eq values is estimated at 10-20‰. The effects of functional groups were found to increase the value of α eq for H next to electron-donating groups, e.g. sbnd OR, sbnd OH or sbnd O(C dbnd O)R, and to decrease the value of α eq for H next to electron-withdrawing groups, e.g. sbnd (C dbnd O)R or sbnd (C dbnd O)OR. Smaller but significant functional group effects are also observed for H β and sometimes H γ. By summing over individual H positions, we estimate the equilibrium fractionation relative to water to be -90‰ to -70‰ for n-alkanes and around -100‰ for pristane and phytane. The temperature dependence of these fractionations is very weak between 0 and 100 °C. Our estimates of α eq agree well with field data for thermally mature hydrocarbons (δ 2H values between -80‰ and -110‰ relative to water). Therefore the observed δ 2H increase of individual hydrocarbons and the disappearance of the biosynthetic δ 2H offset between n-alkyl and linear isoprenoid lipids during maturation of organic matter can be confidently attributed to H exchange towards an equilibrium state. Our results also indicate that many n-alkyl lipids are biosynthesized with δ 2H values that are close to equilibrium with water. In these cases, constant down-core δ 2H values for n-alkyl lipids cannot be reliably used to infer a lack of isotopic exchange.

  2. Chiral Epoxides via Borane Reduction of 2-Haloketones Catalyzed By Spiroborate Ester: Application to the Synthesis of Optically Pure 1,2-Hydroxy Ethers and 1,2-Azido Alcohols

    PubMed Central

    Huang, Kun; Wang, Haiyang; Stepanenko, Viatcheslav; De Jesús, Melvin; Torruellas, Carilyn; Correa, Wildeliz; Ortiz-Marciales, Margarita

    2011-01-01

    An enantioselective borane-mediated reduction of a variety of 2-haloketones using 10% of spiroaminoborate ester 1 as catalyst is described. By a simple basic workup of 2-halohydrins, optically active epoxides are obtained in high yield and with excellent enantiopurity (up to 99% ee). Ring opening of oxiranes with phenoxides or sodium azide is investigated under different reaction conditions affording nonracemic 1,2-hydroxy ethers and 1,2-azido alcohols with excellent enantioselectivity (99% ee) and in good to high chemical yield. PMID:21294519

  3. Radiolabeled cholesteryl ethers trace LDL cholesteryl esters but not HDL cholesteryl esters in the rat.

    PubMed

    Terpstra, A H

    1995-01-01

    The intravascular metabolism of cholesteryl [1-14C]oleoyl ester and [1,2-3H(N)]cholesteryl palmityl ether was compared in the rat, an animal species without plasma cholesteryl ester transfer activity (CETA). The tracers had identical plasma disappearance rates when they were incorporated into human or rat low density lipoproteins (LDL). Fractional catabolic rates (FCR) were 0.081 +/- 0.014 h-1 and 0.080 +/- 0.013 h-1 for human LDL ester and ether and 0.098 +/- 0.007 h-1 and 0.101 +/- 0.007 h-1 for rat LDL ester and ether, respectively. In contrast, the ether had plasma disappearance rates that were 24%-25% lower than the ester when they were incorporated into human or rat high density lipoproteins (HDL). FCR were 0.230 +/- 0.020 and 0.173 +/- 0.030 h-1 for human HDL ester and ether and 0.131 +/- 0.020 h-1 and 0.100 +/- 0.017 h-1 for rat HDL ester and ether respectively. Biological screening of the rat HDL preparations did not affect these differences. The results of these studies indicate that in the absence of plasma CETA, cholesteryl ethers can be used to trace LDL cholesteryl esters but not to trace HDL cholesteryl esters. PMID:7772060

  4. Synthesis of ethers from esters via Fe-catalyzed hydrosilylation.

    PubMed

    Das, Shoubhik; Li, Yuehui; Junge, Kathrin; Beller, Matthias

    2012-11-11

    Triiron dodecacarbonyl allows for the selective reduction of esters into the corresponding ethers. This protocol has a wide substrate scope. In addition, cholesteryl pelarogonate has been reduced under the reaction conditions with an excellent yield. PMID:23024977

  5. Review of glycol ether and glycol ether ester solvents used in the coating industry.

    PubMed Central

    Smith, R L

    1984-01-01

    Ethylene oxide-based glycol ether and glycol ether ester solvents have been used in the coatings industry for the past fifty years. Because of their excellent performance properties (evaporation rate, blush resistance, flow-out and leveling properties, solubility for coating resins, solvent activity, mild odor, good coupling ability, good solvent release) a complete line of ethylene oxide-based solvents of various molecular weights has been developed. These glycol ether and glycol ether ester solvents have better solvent activity for coating resin than ester or ketone solvents in their evaporation rate range. The gloss, flow and leveling, and general performance properties of many coating systems are dependent on the use of these products in the coating formula. Because of the concern about the toxicity of certain ethylene oxide-based solvents, other products are being evaluated as replacements in coating formulas. PMID:6499793

  6. Analysis of alcohols, as dimethylglycine esters, by electrospray ionization tandem mass spectrometry.

    PubMed

    Johnson, D W

    2001-03-01

    Dimethylglycine (DMG) esters are new derivatives for the rapid, sensitive and selective analysis of primary and secondary alcohols, in complex mixtures, by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Their development was inspired by the use of the complementary dimethylaminoethyl esters for the trace, rapid analysis of fatty acids. DMG esters are simply prepared by heating a dichloromethane solution of the imidazolide of dimethylglycine, containing triethylamine, and an alcohol. DMG esters of long-chain fatty alcohols, isoprenoidal alcohols and hydroxy-acids are analysed by electrospray ionization tandem mass spectrometry with a precursor ion of m/z 104 scan. Diols, glyceryl esters, glyceryl ethers and some sterols are analysed by a neutral loss of 103 Da scan. Trimethylglycine (TMG) ester iodides, prepared by alkylation of DMG esters with methyl iodide, are more sensitive derivatives for molecules containing secondary alcohol groups, such as cholesterol and gibberellic acid. They are analysed by a precursor ion of m/z 118 scan. DMG or TMG derivatives were shown to be at least comparable and sometimes an order of magnitude more sensitive than N-methylpyridyl ether derivatives for ESI-MS/MS analysis of the different classes of alcohols. Applications of these derivatives for the diagnosis of inherited disorders and the analysis of natural products are presented. PMID:11312519

  7. 41. LOOKING WEST AT BUILDING NO. 519, ETHER AND ALCOHOL ...

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

    41. LOOKING WEST AT BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, (LEFT) AND BUILDING NO. 521, ETHER VAULT, (RIGHT) IN FOREGROUND - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  8. 37. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, NORTHWEST ...

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

    37. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, NORTHWEST CORNER OF BUILDING. BUILDING NO. 521 (ETHER VAULT) IN BACKGROUND LEFT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  9. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

    1992-01-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

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

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

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

  11. Reductive Etherification of Fatty Acids or Esters with Alcohols using Molecular Hydrogen.

    PubMed

    Erb, Benjamin; Risto, Eugen; Wendling, Timo; Gooßen, Lukas J

    2016-06-22

    In the presence of a catalyst system consisting of a ruthenium/triphos complex and the Brønsted acid trifluoromethanesulfonimide, mixtures of fatty acids and aliphatic alcohols are converted into the corresponding ethers at 70 bar H2 . The protocol allows the sustainable one-step synthesis of valuable long-chain ether fragrances, lubricants, and surfactants from renewable sources. The reaction protocol is extended to various fatty acids and esters both in pure form and as mixtures, for example, tall oil acids or rapeseed methyl ester (RME). Even the mixed triglyceride rapeseed oil was converted in one step. PMID:27214823

  12. Production of durene from alcohols and ethers

    SciTech Connect

    Fowles, P. E.; Yan, T. Y.

    1985-06-18

    Durene is recovered from a mixture rich in durene and containing hydrocarbons boiling in the gasoline range by cooling the mixture to a point where crystallization occurs and separating the crystallized durene. The durene subsequently is washed with a wash fluid. The wash fluid which can be methanol, is returned to a process wherein it is converted to gasoline and durene. The separated mother liquor is added to the gasoline fraction. The original mixture of durene and gasoline is obtained by the catalytic conversion of alcohols and ethers.

  13. 39. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, LOOKING ...

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

    39. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, LOOKING AT SOUTHWEST CORNER WITH BUILDING NO. 521, ETHER VAULT, AND BUILDING NO. 519-A, ETHER & ALOCOHL STORAGE TANKS, IN BACKGROUND RIGHT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  14. 48. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

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

    48. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, 5TH LEVEL, LOOKING NORTH AT ETHER AND ALCOHOL CONDENSERS AT TOP OF TOWER. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  15. 47. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

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

    47. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, 4TH LEVEL, LOOKING NORTH AT TOPS OF ALCOHOL AND ETHER DISTILLATION TOWERS. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  16. Regioselective carbon-oxygen bond cleavage reactions of aromatic ethers and esters with potassium metal/18-crown-6/THF as the electron-transfer reagent

    SciTech Connect

    Fish, R.H.; Dupon, J.W.

    1988-10-28

    The facile carbon-oxygen bond cleavage reactions of a variety of aromatic ethers and esters were studied with an electron-transfer reagent that consisted of potassium metal and 18-crown-6 in tetrahydrofuran (THF). The relative rates of carbon-oxygen bond cleavage, with these aromatic ethers and esters under electron-transfer conditions, was studied in competition with the standard, diphenyl ether. The order of relative reactivities was as follows: phenyl 2-hydroxybenzoate (10) (>2.0); phenyl 2-methoxybenzoate (11) (>2.0); phenyl 4-methoxybenzoate (12) (>2.0); 2-methoxyphenyl benzoate (13) (>2.0); 4-methoxyphenyl benzoate (14) (>2.0); 4-hydroxyphenyl benzoate (15) (1.6); benzyl benzoate (9) (1.3); 4-methoxyphenyl phenyl ether (5) (1.15); phenyl benzoate (8) (1.04); diphenyl ether (1) (1.0); dibenzyl ether (2) (0.98); 2-methoxyphenyl phenyl ether (6) (0.97); benzyl phenyl ether (3) (0.96); phenethyl phenyl ether (7) (0.77); and 4-hydroxyphenyl phenyl ether (4) (<0.1). From these relative rates, it is clear that electron-donating groups increase the relative rates of C-O bond cleavage in aromatic esters. Conversely, a methoxyl group has no apparent effect on the relative rates of aromatic ether C-O bond cleavage, while a hydroxyl group dramatically decreases the rate. Proton donors, tert-butyl alcohol and hydroquinone, decreased the rate of diphenyl ether cleavage. The regioselectivity for C-O bond cleavage of esters 8-15, i.e., carbonyl-oxygen versus carboxyl-carbon cleavage, showed selective carbonyl-oxygen bond cleavage.

  17. 36. BUILDINGS NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, AND ...

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

    36. BUILDINGS NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, AND NO. 523, REFRIGERATION PLANT BUILDING, LOOKING EAST. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  18. 44. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

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

    44. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, LOOKING UP DISTILLATION TOWER FROM 2ND LEVEL. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  19. Fatty acid alcohol ester-synthesizing activity of lipoprotein lipase.

    PubMed

    Tsujita, T; Sumiyoshi, M; Okuda, H

    1999-12-01

    The fatty acid alcohol ester-synthesizing activity of lipoprotein lipase (LPL) was characterized using bovine milk LPL. Synthesizing activities were determined in an aqueous medium using oleic acid or trioleylglycerol as the acyl donor and equimolar amounts of long-chain alcohols as the acyl acceptor. When oleic acid and hexadecanol emulsified with gum arabic were incubated with LPL, palmityl oleate was synthesized, in a time- and dose-dependent manner. Apo-very low density lipoprotein (apoVLDL) stimulated LPL-catalyzed palmityl oleate synthesis. The apparent equilibrium ratio of fatty acid alcohol ester/oleic acid was estimated using a high concentration of LPL and a long (20 h) incubation period. The equilibrium ratio was affected by the incubation pH and the alcohol chain length. When the incubation pH was below pH 7.0 and long chain fatty acyl alcohols were used as substrates, the fatty acid alcohol ester/free fatty acid equilibrium ratio favored ester formation, with an apparent equilibrium ratio of fatty acid alcohol ester/fatty acid of about 0.9/0.1. The equilibrium ratio decreased sharply at alkaline pH (above pH 8.0). The ratio also decreased when fatty alcohols with acyl chains shorter than dodecanol were used. When a trioleoylglycerol/fatty acyl alcohol emulsion was incubated with LPL, fatty acid alcohol esters were synthesized in a dose- and time-dependent fashion. Fatty acid alcohol esters were easily synthesized from trioleoylglycerol when fatty alcohols with acyl chains longer than dodecanol were used, but synthesis was decreased with fatty alcohols with acyl chain lengths shorter than decanol, and little synthesizing activity was detected with shorter-chain fatty alcohols such as butanol or ethanol. PMID:10578059

  20. Synthesis and biological evaluation of arctigenin ester and ether derivatives as activators of AMPK.

    PubMed

    Shen, Sida; Zhuang, Jingjing; Chen, Yijia; Lei, Min; Chen, Jing; Shen, Xu; Hu, Lihong

    2013-07-01

    A series of new arctigenin and 9-deoxy-arctigenin derivatives bearing different ester and ether side chains at the phenolic hydroxyl positions are designed, synthesized, and evaluated for activating AMPK potency in L6 myoblasts. Initial biological evaluation indicates that some alkyl ester and phenethyl ether arctigenin derivatives display potential activities in AMPK phosphorylation improvement. Further structure-activity relationship analysis shows that arctigenin ester derivatives 3a, 3h and 9-deoxy-arctigenin phenethyl ether derivatives 6a, 6c, 6d activate AMPK more potently than arctigenin. Moreover, the 2-(3,4-dimethoxyphenyl)ethyl ether moiety of 6c has been demonstrated as a potential functional group to improve the effect of AMPK phosphorylation. The structural optimization of arctigenin leads to the identification of 6c as a promising lead compound that exhibits excellent activity in AMPK activation. PMID:23673223

  1. Enzymatic network for production of ether amines from alcohols.

    PubMed

    Palacio, Cyntia M; Crismaru, Ciprian G; Bartsch, Sebastian; Navickas, Vaidotas; Ditrich, Klaus; Breuer, Michael; Abu, Rohana; Woodley, John M; Baldenius, Kai; Wu, Bian; Janssen, Dick B

    2016-09-01

    We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production of the desired ether amines from the corresponding ether alcohols with inorganic ammonium as the only additional substrate. To examine conversion, individual and overall reaction equilibria were established. Using these data, it was found that the experimentally observed conversions of up to 60% observed for reactions containing 10 mM alcohol and up to 280 mM ammonia corresponded well to predicted conversions. The results indicate that efficient amination can be driven by high concentrations of ammonia and may require improving enzyme robustness for scale-up. Biotechnol. Bioeng. 2016;113: 1853-1861. © 2016 Wiley Periodicals, Inc. PMID:26915048

  2. Biodegradable poly(ether ester urethane)urea elastomers based on poly(ether ester) triblock copolymers and putrescine: synthesis, characterization and cytocompatibility.

    PubMed

    Guan, Jianjun; Sacks, Michael S; Beckman, Eric J; Wagner, William R

    2004-01-01

    Polymers with elastomeric mechanical properties, tunable biodegradation properties and cytocompatibility would be desirable for numerous biomedical applications. Toward this end a series of biodegradable poly(ether ester urethane)urea elastomers (PEEUUs) based on poly(ether ester) triblock copolymers were synthesized and characterized. Poly(ether ester) triblock copolymers were synthesized by ring-opening polymerization of epsilon-caprolactone with polyethylene glycol (PEG). PEEUUs were synthesized from these triblock copolymers and butyl diisocyanate, with putrescine as a chain extender. PEEUUs exhibited low glass transition temperatures and possessed tensile strengths ranging from 8 to 20MPa and breaking strains from 325% to 560%. Increasing PEG length or decreasing poly(caprolactone) length in the triblock segment increased PEEUU water absorption and biodegradation rate. Human umbilical vein endothelial cells cultured in a medium supplemented with PEEUU biodegradation solution suggested a lack of degradation product cytotoxicity. Endothelial cell adhesion to PEEUUs was less than 60% of tissue culture polystyrene and was inversely related to PEEUU hydrophilicity. Surface modification of PEEUUs with ammonia gas radio-frequency glow discharge and subsequent immobilization of the cell adhesion peptide Arg-Gly-Asp-Ser increased endothelial adhesion to a level equivalent to tissue culture polystyrene. These biodegradable PEEUUs thus possessed properties that would be amenable to applications where high strength and flexibility would be desirable and exhibited the potential for tuning with appropriate triblock segment selection and surface modification. PMID:14580912

  3. 45. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

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

    45. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, CONTROL PANEL LEVEL (2ND DECK), LOOKING AT 'MIXED SOLVENT UNIT' CONTROL PANEL (LOOKING EAST). - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  4. 43. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

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

    43. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, NORTH WING, 1ST LEVEL, LOOKING SOUTHWEST AT EQUIPMENT USED TO CONDENSE SOLVENT VAPORS TRANSMITTED BY SOLVENT RECOVERY DUCT FROM BUILDING NO. 527. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  5. 42. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, ...

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

    42. BUILDING NO. 519, ETHER AND ALCOHOL RECOVERY HOUSE, INTERIOR, NORTH WING, 1ST LEVEL, VIEW OF FILTERS AND BLOWERS FOR SOLVENT VAPORS FROM BUILDING NO. 527. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  6. Quantum calculations of the electro-optical parameters of haloid ethers, esters, amides and carbamates

    NASA Astrophysics Data System (ADS)

    Furer, V. L.

    1992-03-01

    Force and electro-optical parameters of haloid ethers, esters, amides and carbamates were calculated using the MINDO/3 method. The obtained values of parameters, frequencies and intensities of bands in IR spectra are in good accordance with experiment. The changes of molecular parameters due to the electronic interactions and conformational transitions are discussed.

  7. Silane/iodine-based cleavage of esters and ethers under neutral conditions*

    PubMed Central

    Ho, Tse-Lok; Olah, George A.

    1978-01-01

    New, efficient cleavage of carboxylic esters with iodotrimethylsilane or a mixture of phenyltrimethylsilane and iodine is described. Essentially neutral conditions can be maintained throughout the reactions. Ethers can be dealkylated by the latter method in high yields. The mechanism of the cleavage reactions is considered to include six-membered ring homopolar transition states. PMID:16592482

  8. Amidation of esters with amino alcohols using organobase catalysis.

    PubMed

    Caldwell, Nicola; Campbell, Peter S; Jamieson, Craig; Potjewyd, Frances; Simpson, Iain; Watson, Allan J B

    2014-10-01

    A catalytic protocol for the base-mediated amidation of unactivated esters with amino alcohol derivatives is reported. Investigations into mechanistic aspects of the process indicate that the reaction involves an initial transesterification, followed by an intramolecular rearrangement. The reaction is highly general in nature and can be extended to include the synthesis of oxazolidinone systems through use of dimethyl carbonate. PMID:25226088

  9. High octane ethers from synthesis gas-derived alcohols. Technical progress report, October--December 1991

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.; Feeley, O.C.

    1992-01-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  10. Catalytic Dealkylation of Ethers to Alcohols on Metal Surfaces.

    PubMed

    Yang, Biao; Lin, Haiping; Miao, Kangjian; Zhu, Pan; Liang, Liangbo; Sun, Kewei; Zhang, Haiming; Fan, Jian; Meunier, Vincent; Li, Youyong; Li, Qing; Chi, Lifeng

    2016-08-16

    On-surface synthesis has prompted much interest in recent years because it provides an alternative strategy for controlling chemical reactions and allows for the direct observation of reaction pathways. Herein, we combined scanning tunneling microscopy and density functional theory to provide extensive evidence for the conversion of alkoxybenzene-containing ethers into alcohols by means of surface synthesis. The reported dealkylation reactions are finely controlled by the annealing parameters, which govern the onset of successive alkyl chains dissociations. Moreover, density functional theory calculations elucidate the details of the reaction pathways, showing that dealkylation reactions are surface-assisted and very different from their homogeneous analogues in solution. PMID:27432690

  11. Indoor air guide values for glycol ethers and glycol esters-A category approach.

    PubMed

    Mangelsdorf, Inge; Kleppe, Sara Nordqvist; Heinzow, Birger; Sagunski, Helmut

    2016-07-01

    The German Committee on Indoor Guide Values issues indoor air guide values to protect public health. For health evaluation of glycol ethers and glycol esters in air, the entire group of substances with data for 47 chemicals was analyzed in order to gain a consistent assessment. For some glycol ethers reproductive and hematological effects are of central interest, whereas for others effects on liver and kidneys are crucial. Moreover, some glycol ethers have also been shown to cause irritation of the respiratory tract. For 14 chemicals, suitable inhalation studies were available for deriving specific guide values, or analogies to closely related substances could be drawn. For these chemicals individual indoor air guide values were derived, the respective guide value I ranging from 0.02 to 2mg/m(3). Guide values were derived according to the procedures issued by the Committee, considering the exposure duration in indoor air compared to animal studies or the situation at workplaces, the duration of the respective study, species differences, and interindividual variability including special sensitivity of children. For glycol ethers with insufficient data default guide values II and I of 0.05 and 0.005ppm, respectively, were recommended based on statistical analyses of the available data on all glycol ethers and on evaluation of single studies. For evaluation of combined effects additivity is assumed. PMID:27157117

  12. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  13. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  14. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  15. 40 CFR 721.7250 - Polyaziridinyl ester of an aliphatic alcohol (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... alcohol (generic). 721.7250 Section 721.7250 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.7250 Polyaziridinyl ester of an aliphatic alcohol (generic). (a... generically as a polyaziridinyl ester of an aliphatic alcohol (PMN P-01-97) is subject to reporting under...

  16. Boundary lubrication of formulated C-ether in air to 300 deg C. 1: Phosphorus ester additives

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Hady, W. F.

    1972-01-01

    Friction and wear measurements were made on CVM M-50 steel lubricated with three C-ether (modified polyphenyl ether) formulations in dry and wet air. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, a 17-meter-perminute (100-rpm) surface speed, and a 25 to 300 C (77 to 572 F) disk temperature range. The C-ether base fluid and the three formulated C-ether fluids yielded lower wear than the Type 2 ester over the entire temperature range. All C-ether fluids exhibited slightly higher friction coefficients than the ester from 150 to 300 C (302 to 572 F) and similar values from 25 to 150 C (77 to 302 F). In general, lower wear rates were observed with the C-ethers when tested in wet air as compared to a dry air atmosphere.

  17. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; DeTavernier, S.; Johannson, M.; Kieke, M.; Bastian, R.D.

    1991-07-01

    The temperature dependence of ether synthesis, particularly unsymmetric methylisobutylether (MIBE), was carried out over the Nafion-H microsaddles (MS) catalyst. The principal product formed under the rather severe reaction conditions of 1100 psig pressure and temperatures in the range of 123--157{degree}C was the expected MIBE formed directly by coupling the methanol/isobutanol reactants. In addition, significantly larger quantities of the dimethylether (DME) and hydrocarbon products were observed than were obtained under milder reaction conditions. Deactivation of the Nafion-H MS catalyst was determined by periodically testing the catalyst under a given set of reaction conditions for the synthesis of MIBE and MTBE from methanol/isobutanol = 2/1, i.e. 123{degree}C, 1100 psig, and total GHSV = 248 mol/kg cat/hr. After carrying out various tests over a period of 2420 hr, with intermittant periods of standing under nitrogen at ambient conditions, the yields of MIBE and MTBE had decreased by 25% and 41%, respectively. In order to gain insight into the role of the surface acidity in promoting the selective coupling of the alcohols to form the unsymmetric ether, the strengths of the acid sites on the catalysts are still being probed by calorimetric titrations in non-aqueous solutions. 11 refs., 13 figs., 9 tabs.

  18. Ether- versus ester-linked phospholipid bilayers containing either linear or branched apolar chains.

    PubMed

    Balleza, Daniel; Garcia-Arribas, Aritz B; Sot, Jesús; Ruiz-Mirazo, Kepa; Goñi, Félix M

    2014-09-16

    We studied the properties of bilayers formed by ether-and ester-containing phospholipids, whose hydrocarbon chains can be either linear or branched, using sn-1,2 dipalmitoyl, dihexadecyl, diphytanoyl, and diphytanyl phosphatidylcholines (DPPC, DHPC, DPhoPC, and DPhPC, respectively) either pure or in binary mixtures. Differential scanning calorimetry and confocal fluorescence microscopy of giant unilamellar vesicles concurred in showing that equimolar mixtures of linear and branched lipids gave rise to gel/fluid phase coexistence at room temperature. Mixtures containing DHPC evolved in time (0.5 h) from initial reticulated domains to extended solid ones when an equilibrium was achieved. The nanomechanical properties of supported planar bilayers formed by each of the four lipids studied by atomic force microscopy revealed average breakdown forces Fb decreasing in the order DHPC ≥ DPPC > DPhoPC > DPhPC. Moreover, except for DPPC, two different Fb values were found for each lipid. Atomic force microscopy imaging of DHPC was peculiar in showing two coexisting phases of different heights, probably corresponding to an interdigitated gel phase that gradually transformed, over a period of 0.5 h, into a regular tilted gel phase. Permeability to nonelectrolytes showed that linear-chain phospholipids allowed a higher rate of solute + water diffusion than branched-chain phospholipids, yet the former supported a smaller extent of swelling of the corresponding vesicles. Ether or ester bonds appeared to have only a minor effect on permeability. PMID:25229144

  19. Ether- versus Ester-Linked Phospholipid Bilayers Containing either Linear or Branched Apolar Chains

    PubMed Central

    Balleza, Daniel; Garcia-Arribas, Aritz B.; Sot, Jesús; Ruiz-Mirazo, Kepa; Goñi, Félix M.

    2014-01-01

    We studied the properties of bilayers formed by ether-and ester-containing phospholipids, whose hydrocarbon chains can be either linear or branched, using sn-1,2 dipalmitoyl, dihexadecyl, diphytanoyl, and diphytanyl phosphatidylcholines (DPPC, DHPC, DPhoPC, and DPhPC, respectively) either pure or in binary mixtures. Differential scanning calorimetry and confocal fluorescence microscopy of giant unilamellar vesicles concurred in showing that equimolar mixtures of linear and branched lipids gave rise to gel/fluid phase coexistence at room temperature. Mixtures containing DHPC evolved in time (0.5 h) from initial reticulated domains to extended solid ones when an equilibrium was achieved. The nanomechanical properties of supported planar bilayers formed by each of the four lipids studied by atomic force microscopy revealed average breakdown forces Fb decreasing in the order DHPC ≥ DPPC > DPhoPC >> DPhPC. Moreover, except for DPPC, two different Fb values were found for each lipid. Atomic force microscopy imaging of DHPC was peculiar in showing two coexisting phases of different heights, probably corresponding to an interdigitated gel phase that gradually transformed, over a period of 0.5 h, into a regular tilted gel phase. Permeability to nonelectrolytes showed that linear-chain phospholipids allowed a higher rate of solute + water diffusion than branched-chain phospholipids, yet the former supported a smaller extent of swelling of the corresponding vesicles. Ether or ester bonds appeared to have only a minor effect on permeability. PMID:25229144

  20. 21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... produced by the reaction of either ethylene glycol or glycerol with long chain monobasic acids containing... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyhydric alcohol esters of long chain monobasic... Adjuvants and Production Aids § 178.3780 Polyhydric alcohol esters of long chain monobasic acids....

  1. Reactions of perfluoro-1-alkylcycloalkenes with alcohols and properties of vinyl ethers formed

    SciTech Connect

    Snegirev, V.F.; Makarov, K.N.

    1986-12-10

    Perfluoro-1-alkylcycloalkenes react with alcohols to form products of vinyl and allyl substitution. Alkyl perfluorocycloakenyl ethers readily alkylate the fluoride ion and triethylamine, and by the action of SbF/sub 5/ convert into ..cap alpha.., ..beta..-unsaturated perfluoro ketones. When allyl perfluorocycloalkenyl ethers are heated, they isomerize into the corresponding ..cap alpha..-allylperfluorocycloalkanones.

  2. An Oxidation of Benzyl Methyl Ethers with NBS that Selectively Affords Either Aromatic Aldehydes or Aromatic Methyl Esters

    PubMed Central

    Mayhoub, Abdelrahman S.; Talukdar, Arindam; Cushman, Mark

    2010-01-01

    Either mono- or di-bromination of benzyl methyl ethers can be achieved by controlling the amount of NBS and the temperature. Elimination of methyl bromide from the monobrominated intermediates produces aromatic aldehydes, whereas hydrolysis of the dibrominated intermediates affords aromatic methyl esters in good yields. PMID:20373742

  3. Fate of Tetrabromobisphenol A (TBBPA) and Formation of Ester- and Ether-Linked Bound Residues in an Oxic Sandy Soil.

    PubMed

    Li, Fangjie; Wang, Jiajia; Jiang, Bingqi; Yang, Xue; Nastold, Peter; Kolvenbach, Boris; Wang, Lianhong; Ma, Yini; Corvini, Philippe François-Xavier; Ji, Rong

    2015-11-01

    Bound-residue formation is a major dissipation process of most organic xenobiotics in soil. However, both the formation and nature of bound residues of tetrabromobisphenol A (TBBPA) in soil are unclear. Using a 14C-tracer, we studied the fate of TBBPA in an oxic soil during 143 days of incubation. TBBPA dissipated with a half-life of 14.7 days; at the end of incubation, 19.6% mineralized and 66.5% formed bound residues. Eight extractable metabolites were detected, including TBBPA methyl ethers, single-ring bromophenols, and their methyl ethers. Bound residues (mostly bound to humin) rapidly formed during the first 35 days. The amount of those humin-bound residues then quickly decreased, whereas total bound residues decreased slowly. By contrast, residues bound to humic acids and fulvic acids increased continuously until a plateau was reached. Ester- and ether-linked residues accounted for 9.6-27.0% of total bound residues during the incubation, with ester linkages being predominant. Residues bound via ester linkages consisted of TBBPA, TBBPA monomethyl ether, and an unknown polar compound. Our results indicated that bound-residue formation is the major pathway of TBBPA dissipation in oxic soil and provide first insights into the chemical structure of the reversibly ester-linked bound residues of TBBPA and its metabolites. PMID:26444952

  4. Photochemical dimerization and functionalization of alkanes, ethers, primary alcohols and silanes

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.

    1988-01-01

    The space-time yield and/or the selectivity of the photochemical dimerization of alkanes, ethers, primary alcohols and tertiary silanes with Hg and U.V. light is enhanced by refluxing the substrate in the irradiated reaction zone at a temperature at which the dimer product condenses and remains condensed promptly upon its formation. Cross-dimerization of the alkanes, ethers and silanes with primary alcohols is disclosed, as is the functionalization to aldehydes of the alkanes with carbon monoxide.

  5. Photochemical dimerization and functionalization of alkanes, ethers, primary alcohols and silanes

    DOEpatents

    Crabtree, R.H.; Brown, S.H.

    1988-02-16

    The space-time yield and/or the selectivity of the photochemical dimerization of alkanes, ethers, primary alcohols and tertiary silanes with Hg and U.V. light is enhanced by refluxing the substrate in the irradiated reaction zone at a temperature at which the dimer product condenses and remains condensed promptly upon its formation. Cross-dimerization of the alkanes, ethers and silanes with primary alcohols is disclosed, as is the functionalization to aldehydes of the alkanes with carbon monoxide.

  6. Correlation of elastohydrodynamic film thickness measurements for fluorocarbon type 2 ester, and polyphenyl ether lubricants

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

    1974-01-01

    A minimum films thickness correlation applicable to heavily loaded elastohydrodynamic (EHD) contacts was formulated from experimental data obtained by an X-ray transmission technique. The correlation, based on data generated with fluorocarbon, type II ester, and polyphenyl ether lubricants, extends a previous analysis developed from data for a synthetic paraffinic oil. The resulting correlation represents the data of the four lubricants reasonably well over a large range of operating conditions. Contained within the derived relation is a factor to account for the high-load dependence displayed by the measurements beyond that which is provided for by the theory. Thermal corrections applied to a commonly used film thickness formula showed little improvement to the general disagreement that exists between theory and test. Choice of contact geometry and material are judged to have a relatively mild influence on the form of the semiempirical model.

  7. Surface decorated poly(ester-ether-urethane)s nanoparticles: a versatile approach towards clinical translation.

    PubMed

    Piras, Anna Maria; Sandreschi, Stefania; Malliappan, Sivakumar Ponnurengam; Dash, Mamoni; Bartoli, Cristina; Dinucci, Dinuccio; Guarna, Francesco; Ammannati, Enrico; Masa, Marc; Múčková, Marta; Schmidtová, Ludmila; Chiellini, Emo; Chiellini, Federica

    2014-11-20

    Poly(ester-ether-urethane)s copolymers are a resourceful class of biopolymers for the preparation of nanocarriers for drug delivery applications. However, a simple clinical translation for this synthetic material with biological and quality features is still needed. In this view, poly(ε-caprolactone)-co-poly(ethylene glycol) copolymers were synthesized as semi-bulk pilot (Kg) scale under mild conditions in absence of catalyst, bearing functional termini such as fluorescein tag and anticancer targeting moieties. The obtained materials were processed into surface decorated paclitaxel (PTX) loaded nanoparticles (NPs). The NPs were fully characterized in vitro and in vivo biodistribution in healthy mice evidenced no sign of toxicity and lower levels of PTX in lung and spleen, compared to clinically applied PTX dosage form. PMID:25178828

  8. Synthesis of ethers by GaBr3 -catalyzed reduction of carboxylic acid esters and lactones by siloxanes.

    PubMed

    Biermann, Ursula; Metzger, Jürgen O

    2014-02-01

    Ethers were synthesized by reduction of the respective esters catalyzed by gallium bromide (GaBr3 ) and using siloxanes, preferentially 1,1,3,3-tetramethyldisiloxane, as reductant. Methyl oleate, triglycerides, that is, tributyrine and glyceryl triundec-10-enoate as well as γ- and δ-lactones were converted into the respective ethers in high to moderate yields. γ-Lactones were reduced with high selectivity in the presence of a methyl ester functionality. The reduction has been carried out at room temperature or moderately elevated temperature of up to 60 °C using stoichiometric amounts of the reductant and 0.005-0.01 equiv of GaBr3 as catalyst per ester functionality without any solvent added. After a reaction time of 1-4 h the conversion of the substrate was 100 %. The product was separated from polymeric siloxanes formed as coupled product by simple distillation. PMID:24488681

  9. Amino alcohol-based degradable poly(ester amide) elastomers

    PubMed Central

    Bettinger, Christopher J.; Bruggeman, Joost P.; Borenstein, Jeffrey T.; Langer, Robert S.

    2009-01-01

    Currently available synthetic biodegradable elastomers are primarily composed of crosslinked aliphatic polyesters, which suffer from deficiencies including (1) high crosslink densities, which results in exceedingly high stiffness, (2) rapid degradation upon implantation, or (3) limited chemical moieties for chemical modification. Herein, we have developed poly(1,3-diamino-2-hydroxypropane-co-polyol sebacate)s, a new class of synthetic, biodegradable elastomeric poly(ester amide)s composed of crosslinked networks based on an amino alcohol. These crosslinked networks feature tensile Young’s modulus on the order of 1 MPa and reversable elongations up to 92%. These polymers exhibit in vitro and in vivo biocompatibility. These polymers have projected degradation half-lives up to 20 months in vivo. PMID:18295329

  10. High octane ethers from synthesis gas-derived alcohols. Technical progress report, July 1, 1991--September 30, 1991

    SciTech Connect

    Klier, K.; Herman, R.G.; Johannson, M.; Feeley, O.C.; Bogar, S.; Lawson, E.; Kieke, M.

    1991-11-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobuty ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-butanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  11. Stereospecific nickel-catalyzed cross-coupling reactions of benzylic ethers and esters.

    PubMed

    Tollefson, Emily J; Hanna, Luke E; Jarvo, Elizabeth R

    2015-08-18

    This Account presents the development of a suite of stereospecific alkyl-alkyl cross-coupling reactions employing nickel catalysts. Our reactions complement related nickel-catalyzed stereoconvergent cross-coupling reactions from a stereochemical and mechanistic perspective. Most reactions of alkyl electrophiles with low-valent nickel complexes proceed through alkyl radicals and thus are stereoablative; the correct enantioselective catalyst can favor the formation of one enantiomer. Our reactions, in contrast, are stereospecific. Enantioenriched ethers and esters are cleanly converted to cross-coupled products with high stereochemical fidelity. While mechanistic details are still to be refined, our results are consistent with a polar, two-electron oxidative addition that avoids the formation of radical intermediates. This reactivity is unusual for a first-row transition metal. The cross-coupling reactions engage a range of benzylic ethers and esters, including methyl ethers, tetrahydropyrans, tetrahydrofurans, esters, and lactones. Coordination of the arene substituent to the nickel catalyst accelerates the reactions. Arenes with low aromatic stabilization energies, such as naphthalene, benzothiophene, and furan, serve as the best ligands and provide the highest reactivity. Traceless directing groups that accelerate reactions of sluggish substrates are described, providing partial compensation for arene coordination. Kumada, Negishi, and Suzuki reactions provide incorporation of a broad range of transmetalating agents. In Kumada coupling reactions, a full complement of Grigard reagents, including methyl, n-alkyl, and aryl Grignard reagents, are employed. In reactions employing methylmagnesium iodide, ligation of the nickel catalyst by rac-BINAP or DPEphos provides the highest yield and stereospecificity. For all other Grignard reagents, Ni(dppe)Cl2 has emerged as the best catalyst. Negishi cross-coupling reactions employing dimethylzinc are reported as a strategy to

  12. Stereospecific Nickel-Catalyzed Cross-Coupling Reactions of Benzylic Ethers and Esters

    PubMed Central

    2015-01-01

    Conspectus This Account presents the development of a suite of stereospecific alkyl–alkyl cross-coupling reactions employing nickel catalysts. Our reactions complement related nickel-catalyzed stereoconvergent cross-coupling reactions from a stereochemical and mechanistic perspective. Most reactions of alkyl electrophiles with low-valent nickel complexes proceed through alkyl radicals and thus are stereoablative; the correct enantioselective catalyst can favor the formation of one enantiomer. Our reactions, in contrast, are stereospecific. Enantioenriched ethers and esters are cleanly converted to cross-coupled products with high stereochemical fidelity. While mechanistic details are still to be refined, our results are consistent with a polar, two-electron oxidative addition that avoids the formation of radical intermediates. This reactivity is unusual for a first-row transition metal. The cross-coupling reactions engage a range of benzylic ethers and esters, including methyl ethers, tetrahydropyrans, tetrahydrofurans, esters, and lactones. Coordination of the arene substituent to the nickel catalyst accelerates the reactions. Arenes with low aromatic stabilization energies, such as naphthalene, benzothiophene, and furan, serve as the best ligands and provide the highest reactivity. Traceless directing groups that accelerate reactions of sluggish substrates are described, providing partial compensation for arene coordination. Kumada, Negishi, and Suzuki reactions provide incorporation of a broad range of transmetalating agents. In Kumada coupling reactions, a full complement of Grigard reagents, including methyl, n-alkyl, and aryl Grignard reagents, are employed. In reactions employing methylmagnesium iodide, ligation of the nickel catalyst by rac-BINAP or DPEphos provides the highest yield and stereospecificity. For all other Grignard reagents, Ni(dppe)Cl2 has emerged as the best catalyst. Negishi cross-coupling reactions employing dimethylzinc are reported as

  13. Altering small and medium alcohol selectivity in the wax ester synthase.

    PubMed

    Barney, Brett M; Ohlert, Janet M; Timler, Jacobe G; Lijewski, Amelia M

    2015-11-01

    The bifunctional wax ester synthase/acyl-coenzyme A:diacylglycerol acyltransferase (WS/DGAT or wax ester synthase) catalyzes the terminal reaction in the bacterial wax ester biosynthetic pathway, utilizing a range of alcohols and fatty acyl-CoAs to synthesize the corresponding wax ester. The wild-type wax ester synthase Maqu_0168 from Marinobacter aquaeolei VT8 exhibits a preference for longer fatty alcohols, while applications with smaller alcohols would yield products with desired biotechnological properties. Small and medium chain length alcohol substrates are much poorer substrates for the native enzyme, which may hinder broad application of the wax ester synthase in many proposed biosynthetic schemes. Developing approaches to improve enzyme activity toward specific smaller alcohol substrates first requires a clear understanding of which amino acids of the primary sequences of these enzymes contribute to substrate specificity in the native enzyme. In this report, we surveyed a range of potential residues and identified the leucine at position 356 and methionine at position 405 in Maqu_0168 as residues that affected selectivity toward small, branched, and aromatic alcohols when substituted with different amino acids. This analysis provides evidence of residues that line the binding site for wax ester synthase, which will aid rational approaches to improve this enzyme with specific substrates. PMID:26205519

  14. Synthesis of Biaryl Ethers by the Copper-Catalyzed Chan-Evans-Lam Etherification from Benzylic Amine Boronate Esters.

    PubMed

    Marcum, Justin S; McGarry, Kathryn A; Ferber, Carl J; Clark, Timothy B

    2016-09-01

    The copper-catalyzed etherification of ortho-borylated benzylic amines with phenols has been achieved to provide biaryl ethers that are prevalent in biologically active compounds. A variety of substitution patterns on the aryl boronate ester and the phenol are tolerated under the reaction conditions, providing moderate to high yields. A competition reaction between phenol and aniline revealed condition-dependent selectivity in which the phenol could be highly favored over the aniline. PMID:27490146

  15. Effects of Ether vs. Ester Linkage on Lipid Bilayer Structure and Water Permeability

    PubMed Central

    Guler, S. Deren; Ghosh, D. Dipon; Pan, Jianjun; Matthai, John C.; Zeidel, Mark L.; Nagle, John F.; Tristram-Nagle, Stephanie

    2009-01-01

    The structure and water permeability of bilayers composed of the ether linked lipid, dihexadecylphosphatidylcholine (DHPC), were studied and compared with the ester linked lipid, dipalmitoylphosphaditdylcholine (DPPC). Wide angle x-ray scattering on oriented bilayers in the fluid phase indicate that the area per lipid A is slightly larger for DHPC than for DPPC. Low angle x-ray scattering yields A=65.1Å2 for DHPC at 48°C. LAXS data provide the bending modulus, KC=4.2×10−13erg, and the Hamaker parameter H=7.2×10−14erg for the van der Waals attractive interaction between neighboring bilayers. For the low temperature phases with ordered hydrocarbon chains, we confirm the transition from a tilted Lß’ gel phase to an untilted, interdigitated LßI phase as the sample hydrates at 20°C. Our measurement of water permeability, Pf=0.022 cm/s at 48 °C for fluid phase DHPC is slightly smaller than that of DPPC, (Pf=0.027 cm/s) at 50 °C, consistent with our triple slab theory of permeability. PMID:19416724

  16. Copper-catalyzed oxidative C-O bond formation of 2-acyl phenols and 1,3-dicarbonyl compounds with ethers: direct access to phenol esters and enol esters.

    PubMed

    Park, Jihye; Han, Sang Hoon; Sharma, Satyasheel; Han, Sangil; Shin, Youngmi; Mishra, Neeraj Kumar; Kwak, Jong Hwan; Lee, Cheong Hoon; Lee, Jeongmi; Kim, In Su

    2014-05-16

    A copper-catalyzed oxidative coupling of 2-carbonyl-substituted phenols and 1,3-dicarbonyl compounds with a wide range of dibenzyl or dialkyl ethers is described. This protocol provides an efficient preparation of phenol esters and enol esters in good yields with high chemoselectivity. This method represents an alternative protocol for classical esterification reactions. PMID:24762192

  17. Photochemical dimerization and functionalization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and silanes

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.

    1989-01-01

    The space-time yield and/or the selectivity of the photochemical dimerization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and primary, secondary and tertiary silanes with Hg and U.V. light is enhanced by refluxing the substrate in the irradiated reaction zone at a temperature at which the dimer product condenses and remains condensed promptly upon its formation. Cross-dimerization of the alkanes, ethers and silanes with primary alcohols is disclosed, as is the functionalization to aldehydes of the alkanes with carbon monoxide.

  18. Photochemical dimerization and functionalization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and silanes

    DOEpatents

    Crabtree, R.H.; Brown, S.H.

    1989-10-17

    The space-time yield and/or the selectivity of the photochemical dimerization of alkanes, ethers, primary and secondary alcohols, phosphine oxides and primary, secondary and tertiary silanes with Hg and U.V. light is enhanced by refluxing the substrate in the irradiated reaction zone at a temperature at which the dimer product condenses and remains condensed promptly upon its formation. Cross-dimerization of the alkanes, ethers and silanes with primary alcohols is disclosed, as is the functionalization to aldehydes of the alkanes with carbon monoxide.

  19. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  20. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  1. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  2. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  3. 40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Boric acid (H3BO3), mixed esters with... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1729...

  4. Effects of Blending Alcohols with Poultry Fat Methyl Esters on Cold Flow Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The low temperature operability, kinematic viscosity, and acid value of poultry fat methyl esters were improved with addition of ethanol, isopropanol, and butanol in a linear fashion with increasing alcohol content. The flash point decreased and moisture content increased upon addition of alcohols t...

  5. Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

    PubMed

    Lipp, Alexander; Lahm, Günther; Opatz, Till

    2016-06-01

    A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature. PMID:27128627

  6. Rapid ester biosynthesis screening reveals a high activity alcohol-O-acyltransferase (AATase) from tomato fruit.

    PubMed

    Lin, Jyun-Liang; Zhu, Jie; Wheeldon, Ian

    2016-05-01

    Ethyl and acetate esters are naturally produced in various yeasts, plants, and bacteria. The biosynthetic pathways that produce these esters share a common reaction step, the condensation of acetyl/acyl-CoA with an alcohol by alcohol-O-acetyl/acyltransferase (AATase). Recent metabolic engineering efforts exploit AATase activity to produce fatty acid ethyl esters as potential diesel fuel replacements as well as short- and medium-chain volatile esters as fragrance and flavor compounds. These efforts have been limited by the lack of a rapid screen to quantify ester biosynthesis. Enzyme engineering efforts have also been limited by the lack of a high throughput screen for AATase activity. Here, we developed a high throughput assay for AATase activity and used this assay to discover a high activity AATase from tomato fruit, Solanum lycopersicum (Atf-S.l). Atf1-S.l exhibited broad specificity towards acyl-CoAs with chain length from C4 to C10 and was specific towards 1-pentanol. The AATase screen also revealed new acyl-CoA substrate specificities for Atf1, Atf2, Eht1, and Eeb1 from Saccharomyces cerevisiae, and Atf-C.m from melon fruit, Cucumis melo, thus increasing the pool of characterized AATases that can be used in ester biosynthesis of ester-based fragrance and flavor compounds as well as fatty acid ethyl ester biofuels. PMID:26814045

  7. Process to convert biomass and refuse derived fuel to ethers and/or alcohols

    DOEpatents

    Diebold, J.P.; Scahill, J.W.; Chum, H.L.; Evans, R.J.; Rejai, B.; Bain, R.L.; Overend, R.P.

    1996-04-02

    A process is described for conversion of a feedstock selected from the group consisting of biomass and refuse derived fuel (RDF) to provide reformulated gasoline components comprising a substantial amount of materials selected from the group consisting of ethers, alcohols, or mixtures thereof, comprising: drying said feedstock; subjecting said dried feedstock to fast pyrolysis using a vortex reactor or other means; catalytically cracking vapors resulting from said pyrolysis using a zeolite catalyst; condensing any aromatic byproduct fraction; catalytically alkylating any benzene present in said vapors after condensation; catalytically oligomerizing any remaining ethylene and propylene to higher olefins; isomerizing said olefins to reactive iso-olefins; and catalytically reacting said iso-olefins with an alcohol to form ethers or with water to form alcohols. 35 figs.

  8. Process to convert biomass and refuse derived fuel to ethers and/or alcohols

    DOEpatents

    Diebold, James P.; Scahill, John W.; Chum, Helena L.; Evans, Robert J.; Rejai, Bahman; Bain, Richard L.; Overend, Ralph P.

    1996-01-01

    A process for conversion of a feedstock selected from the group consisting of biomass and refuse derived fuel (RDF) to provide reformulated gasoline components comprising a substantial amount of materials selected from the group consisting of ethers, alcohols, or mixtures thereof, comprising: drying said feedstock; subjecting said dried feedstock to fast pyrolysis using a vortex reactor or other means; catalytically cracking vapors resulting from said pyrolysis using a zeolite catalyst; condensing any aromatic byproduct fraction; catalytically alkylating any benzene present in said vapors after condensation; catalytically oligomerizing any remaining ethylene and propylene to higher olefins; isomerizing said olefins to reactive iso-olefins; and catalytically reacting said iso-olefins with an alcohol to form ethers or with water to form alcohols.

  9. Synthesis and characterization of poly(D,L-lactide)-poly(ethylene glycol) multiblock poly(ether-ester-urethane)s

    NASA Astrophysics Data System (ADS)

    Haw, Tan Ching; Ahmad, Azizan; Anuar, Farah Hannan

    2015-09-01

    In this study, poly(D,L-lactide)-poly(ethylene glycol) multiblock poly(ether-ester-urethane)s was synthesized in the framework of environmental friendly products to meet the need for highly flexible polymers. Triblock copolymer with poly(ethylene glycol) as center block and poly(D,L-lactide) as side block were first synthesized by ring-opening polymerization of D,L-lactide, followed by chain extension reaction of triblocks using hexamethylene diisocyanate (HMDI). NMR and infra-red spectroscopies were used to determine the molecular composition whereas XRD analysis revealed crystallinity behavior of synthesized multiblock copolymers.

  10. Rapid ether and alcohol C-O bond hydrogenolysis catalyzed by tandem high-valent metal triflate + supported Pd catalysts.

    PubMed

    Li, Zhi; Assary, Rajeev S; Atesin, Abdurrahman C; Curtiss, Larry A; Marks, Tobin J

    2014-01-01

    The thermodynamically leveraged conversion of ethers and alcohols to saturated hydrocarbons is achieved efficiently with low loadings of homogeneous M(OTf)n + heterogeneous Pd tandem catalysts (M = transition metal; OTf = triflate; n = 4). For example, Hf(OTf)4 mediates rapid endothermic etheralcohol and alcohol ⇌ alkene equilibria, while Pd/C catalyzes the subsequent, exothermic alkene hydrogenation. The relative C-O cleavage rates scale as 3° > 2° > 1°. The reaction scope extends to efficient conversion of biomass-derived ethers, such as THF derivatives, to the corresponding alkanes. PMID:24354599

  11. Ruthenium(II)-PNN pincer complex catalyzed dehydrogenation of benzyl alcohol to ester: A DFT study

    NASA Astrophysics Data System (ADS)

    Tao, Jingcong; Wen, Li; Lv, Xiaobo; Qi, Yong; Yin, Hailiang

    2016-04-01

    The molecular mechanism of the dehydrogenation of primary alcohol to ester catalyzed by the ruthenium(II)-PNN pincer complex Ru(H)(η2-BH4)(PNN), [PNN: (2-(di-tert-butylphosphinomethyl)-6-(diethlaminomethyl)-pyridine)] has been investigated using density functional theory calculations. The catalytic cycle includes three stages: (stage I) alcohol dehydrogenation to form aldehyde, (stage II) coupling of aldehyde with alcohol to give hemiacetal or ester, and (stage III) hemiacetal dehydrogenation to form ester. Two dehydrogenation reactions occur via the β-H elimination mechanism rather than the bifunctional double hydrogen transfer mechanism, which could be rationalized as the fluxional behavior of the BH4- ligand. At the second stage, the coupling reaction requires alcohol or the ruthenium catalyst as mediator. The formation of hemiacetal through the alcohol-mediated pathway is kinetically favorable than the ruthenium catalyst-mediated one, which may be attributed to the smaller steric hindrance when the aldehyde approaches the alcohol moiety in the reaction system. Our results would be helpful for experimental chemists to design more effective transition metal catalysts for dehydrogenation of alcohols.

  12. Calculations of phase equilibria for mixtures of triglycerides, fatty acids, and their esters in lower alcohols

    NASA Astrophysics Data System (ADS)

    Stepanov, D. A.; Ermakova, A.; Anikeev, V. I.

    2011-01-01

    The objects of study were mixtures containing triglycerides and lower alcohols and also the products of the transesterification of triglycerides, glycerol and fatty acid esters. The Redlich-Kwong-Soave equation of state was used as a thermodynamic model for the phase state of the selected mixtures over wide temperature, pressure, and composition ranges. Group methods were applied to determine the critical parameters of pure substances and their acentric factors. The parameters obtained were used to calculate the phase diagrams and critical parameters of mixtures containing triglycerides and lower alcohols and the products of the transesterification of triglycerides, glycerol and fatty acid esters, at various alcohol/oil ratios. The conditions of triglyceride transesterification in various lower alcohols providing the supercritical state of reaction mixtures were selected.

  13. Rhodium-Catalyzed Enantioselective Intermolecular Hydroalkoxylation of Allenes and Alkynes with Alcohols: Synthesis of Branched Allylic Ethers.

    PubMed

    Liu, Zi; Breit, Bernhard

    2016-07-11

    Regio- and enantioselective additions of alcohols to either terminal allenes or internal alkynes provides access to allylic ethers by using a Rh(I) /diphenyl phosphate catalytic system. This method provides an atom-economic way to obtain chiral aliphatic and aryl allylic ethers in moderate to good yield with good to excellent enantioselectivities. PMID:27244349

  14. High octane ethers from synthesis gas-derived alcohols. Quarterly technical progress report, July--September 1993

    SciTech Connect

    Klier, K.; Herman, R.G.; Feeley, O.C.; Johansson, M.A.

    1993-11-01

    The objective of the proposed research is to synthesize oxygenated fuel ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from coal-derived H{sub 2}/CO/CO{sub 2} synthesis via alcohol mixtures that are rich in methanol and 2-methyl-1-proanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. Both organic and inorganic catalysts will be investigated, and the better catalysts will be subjected to long term performance studies. The project is divided into the following three tasks: (1) synthesis of high octane ethers from alcohol mixtures containing predominantly methanol and 2-methyl-1-propanol over superacid resins, (2) inorganic catalysts for the synthesis of high octane ethers form alcohols, and (3) long term performance and reaction engineering for scale-up of the alcohols-to-ether process. A summary of technical progress is provided in this report.

  15. 21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyhydric alcohol esters of long chain monobasic acids. 178.3780 Section 178.3780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS...

  16. 21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyhydric alcohol esters of long chain monobasic acids. 178.3780 Section 178.3780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS...

  17. 21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyhydric alcohol esters of long chain monobasic acids. 178.3780 Section 178.3780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS...

  18. 21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyhydric alcohol esters of long chain monobasic acids. 178.3780 Section 178.3780 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS...

  19. Ether- and Ester-Bound iso-Diabolic Acid and Other Lipids in Members of Acidobacteria Subdivision 4

    PubMed Central

    Rijpstra, W. Irene C.; Hopmans, Ellen C.; Foesel, Bärbel U.; Wüst, Pia K.; Overmann, Jörg; Tank, Marcus; Bryant, Donald A.; Dunfield, Peter F.; Houghton, Karen; Stott, Matthew B.

    2014-01-01

    Recently, iso-diabolic acid (13,16-dimethyl octacosanedioic acid) has been identified as a major membrane-spanning lipid of subdivisions 1 and 3 of the Acidobacteria, a highly diverse phylum within the Bacteria. This finding pointed to the Acidobacteria as a potential source for the bacterial glycerol dialkyl glycerol tetraethers that occur ubiquitously in peat, soil, lakes, and hot springs. Here, we examined the lipid composition of seven phylogenetically divergent strains of subdivision 4 of the Acidobacteria, a bacterial group that is commonly encountered in soil. Acid hydrolysis of total cell material released iso-diabolic acid derivatives in substantial quantities (11 to 48% of all fatty acids). In contrast to subdivisions 1 and 3 of the Acidobacteria, 6 out of the 7 species of subdivision 4 (excepting “Candidatus Chloracidobacterium thermophilum”) contained iso-diabolic acid ether bound to a glycerol in larger fractional abundance than iso-diabolic acid itself. This is in agreement with the analysis of intact polar lipids (IPLs) by high-performance liquid chromatography-mass spectrometry (HPLC-MS), which showed the dominance of mixed ether-ester glycerides. iso-Diabolic acid-containing IPLs were not identified, because these IPLs are not released with a Bligh-Dyer extraction, as observed before when studying lipid compositions of subdivisions 1 and 3 of the Acidobacteria. The presence of ether bonds in the membrane lipids does not seem to be an adaptation to temperature, because the five mesophilic isolates contained a larger amount of ether lipids than the thermophile “Ca. Chloracidobacterium thermophilum.” Furthermore, experiments with Pyrinomonas methylaliphatogenes did not reveal a major influence of growth temperature over the 50 to 69°C range. PMID:24928878

  20. High octane ethers from synthesis gas-derived alcohols. [Catalyst names: Amberlyst-15, BioRad AG 50WX2, Nafion-H microsaddles, and Purolite 150

    SciTech Connect

    Klier, K.; Herman, R.G.; Johannson, M.; Feeley, O.C.; Bogar, S.; Lawson, E.; Kieke, M.

    1991-11-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobuty ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-butanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  1. TERATOLOGY AND POSTNATAL STUDIES IN RATS OF THE PROPYLENE GLYCOL BUTYL ETHER AND ISOOCTYL ESTERS OF 2,4-DICHLOROPHENOXYACETIC ACID

    EPA Science Inventory

    The purpose of this study was to evaluate the teratogenic potential of the propylene glycol butyl ether (PGBE) and isooctyl (IO) esters of 2,4-dichlorophenoxyacetic acid (2,4-D). Accordingly, groups of pregnant CD rats received daily oral doses of PGBE or IO equivalent to 0, 6.25...

  2. Ester synthesis catalyzed by Mucor miehei lipase immobilized on magnetic polysiloxane-polyvinyl alcohol particles.

    PubMed

    Bruno, Laura M; de Lima Filho, José L; de M Melo, Eduardo H; de Castro, Heizir F

    2004-01-01

    Mucor miehei lipase was immobilized on magnetic polysiloxane-polyvinyl alcohol particles by covalent binding with high activity recovered. The performance of the resulting immobilized biocatalyst was evaluated in the synthesis of flavor esters using heptane as solvent. The impact on reaction rate was determined for enzyme concentration, molar ratio of the reactants, carbon chain length of the reactants, and alcohol structure. Ester synthesis was maximized for substrates containing excess acyl donor and lipase loading of 25 mg/mL. The biocatalyst selectivity for the carbon chain length was found to be different concerning the organic acids and alcohols. High reaction rates were achieved for organic acids with 8 or 10 carbons, whereas increasing the alcohol carbon chain length from 4 to 8 carbons gave much lower esterification yields. Optimal reaction rate was determined for the synthesis of butyl caprylate (12 carbons). Esterification performance was also dependent on the alcohol structure, with maximum activity occurring for primary alcohol. Secondary and tertiary alcohols decreased the reaction rates by more than 40%. PMID:15054206

  3. Reactivity Study of a Pyridyl-1-azaallylgermanium(I) Dimer: Synthesis of Heavier Ether and Ester Analogues of Germanium.

    PubMed

    Leung, Wing-Por; Chan, Yuk-Chi; So, Cheuk-Wai; Mak, Thomas C W

    2016-04-01

    The reactivity study of a pyridyl-1-azaallylgermanium(I) dimer LGe-GeL [1; L = N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)] with different stoichiometric ratios of elemental selenium and tellurium is described. The reactions of 1 with 1 equiv of selenium and tellurium afforded the first examples of heavier ether analogues of germanium, bis(germylene) selenide and telluride LGe(μ-E)GeL [E = Se (2) and Te (3)], respectively. Meanwhile, the reactions of 1 with 2 equiv of selenium and tellurium gave the heavier ester analogues LGe═E(μ-E)GeL [E = Se (4) and (5)]. All compounds have been characterized by X-ray crystallography and multinuclear NMR spectroscopy. PMID:26991426

  4. Effects of 2,3-Dehydrosilybin and Its Galloyl Ester and Methyl Ether Derivatives on Human Umbilical Vein Endothelial Cells.

    PubMed

    Karas, Daniel; Gažák, Radek; Valentová, Kateřina; Chambers, Christopher S; Pivodová, Veronika; Biedermann, David; Křenková, Alena; Oborná, Ivana; Kuzma, Marek; Cvačka, Josef; Ulrichová, Jitka; Křen, Vladimír

    2016-04-22

    The effects in vitro of 2,3-dehydrosilybin and several galloyl esters and methyl ethers on the viability, proliferation, and migration of human umbilical vein endothelial cells (HUVECs) were evaluated. The monogalloyl esters were synthesized by a chemoselective esterification method or by Steglich esterification of suitably protected 2,3-dehydrosilybin (1) with protected gallic acid. 2,3-Dehydrosilybin (1) displayed more potent cytotoxic, antiproliferative, and antimigratory activities (IC50 12.0, 5.4, and 12.2 μM, respectively) than silybin. The methylated derivatives were less active, with the least potent being 3,7-di-O-methyl-2,3-dehydrosilybin (6). On the other hand, galloylation at C-7 OH and C-23 OH markedly increased the cytotoxicity and the effects on the proliferation and migration of HUVECs. The most active derivative was 7-O-galloyl-2,3-dehydrosilybin (13; IC50 value of 3.4, 1.6, and 4.7 μM in the cytotoxicity, inhibition of proliferation, and antimigratory assays, respectively). Overall, this preliminary structure-activity relationship study demonstrated the importance of a 2,3-double bond, a C-7 OH group, and a galloyl moiety in enhancing the activity of flavonolignans toward HUVECs. PMID:27015547

  5. Sublethal and acute toxicity of the ethylene glycol butyl ether ester formulation of triclopyr to juvenile coho salmon (Oncorhynchus kisutch).

    PubMed

    Johansen, J A; Geen, G H

    1990-01-01

    The toxicity of Garlon4, the ethylene glycol butyl ether ester formulation of the herbicide tryclopyr, to juvenile coho salmon (Oncorhynchus kisutch) was investigated at several lethal and sublethal concentrations. Fish behavior, random activity and oxygen uptake were monitored. Coho salmon exhibited three distinct responses related to concentration and duration of exposure: (1) at concentrations greater than 0.56 mg/L fish were initially lethargic, then regressed to a highly distressed condition characterized by elevated oxygen uptake and finally death, (2) at 0.32-0.43 mg/L fish were lethargic throughout the exposure period with reduced oxygen uptake, and (3) at concentrations less than or equal to 0.10 mg/L fish were hypersensitive to stimuli, exhibiting elevated activity and oxygen uptake levels during photoperiod transitions. Whole body residue analysis showed that uptake of the ester and subsequent hydrolysis to the acid form in the fish was rapid, with significant accumulation of the acid in the tissues. This suggests that some threshold tissue concentrations were associated with the observed results. For juvenile coho salmon the 96-hr LC50 of Garlon4 was 0.84 mg/L. PMID:2386416

  6. Olfactory Impact of Higher Alcohols on Red Wine Fruity Ester Aroma Expression in Model Solution.

    PubMed

    Cameleyre, Margaux; Lytra, Georgia; Tempere, Sophie; Barbe, Jean-Christophe

    2015-11-11

    This study focused on the impact of five higher alcohols on the perception of fruity aroma in red wines. Various aromatic reconstitutions were prepared, consisting of 13 ethyl esters and acetates and 5 higher alcohols, all at the average concentrations found in red wine. These aromatic reconstitutions were prepared in several matrices. Sensory analysis revealed the interesting behavior of certain compounds among the five higher alcohols following their individual addition or omission. The "olfactory threshold" of the fruity pool was evaluated in several matrices: dilute alcohol solution, dilute alcohol solution containing 3-methylbutan-1-ol or butan-1-ol individually, and dilute alcohol solution containing the mixture of five higher alcohols, blended together at various concentrations. The presence of 3-methylbutan-1-ol or butan-1-ol alone led to a significant decrease in the "olfactory threshold" of the fruity reconstitution, whereas the mixture of alcohols raised the olfactory threshold. Sensory profiles highlighted changes in the perception of fruity nuances in the presence of the mixture of higher alcohols, with specific perceptive interactions, including a relevant masking effect on fresh- and jammy-fruit notes of the fruity mixture in both dilute alcohol solution and dearomatized red wine matrices. When either 3-methylbutan-1-ol or butan-1-ol was added to the fruity reconstitution in dilute alcohol solution, an enhancement of butyric notes was reported with 3-methylbutan-1-ol and fresh- and jammy-fruit with butan-1-ol. This study, the first to focus on the impact of higher alcohols on fruity aromatic expression, revealed that these compounds participate, both quantitatively and qualitatively, in masking fruity aroma perception in a model fruity wine mixture. PMID:26529563

  7. UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers

    NASA Technical Reports Server (NTRS)

    Bernstein, M. P.; Sandford, S. A.; Allamandola, L. J.; Gillette, J. S.; Clemett, S. J.; Zare, R. N.

    1999-01-01

    Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.

  8. General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols.

    PubMed

    Deibl, Nicklas; Kempe, Rhett

    2016-08-31

    The borrowing hydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon-carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based on iridium and ruthenium have been used to accomplish these reactions. Herein, we report on the first base metal-catalyzed α-alkylation of unactivated amides and esters by alcohols. Cobalt complexes stabilized with pincer ligands, recently developed in our laboratory, catalyze these reactions very efficiently. The precatalysts can be synthesized easily from commercially available starting materials on a multigram scale and are self-activating under the basic reaction conditions. This Co catalyst class is also able to mediate alkylation reactions of both esters and amides. In addition, we apply the methodology to synthesize ketones and to convert alcohols into aldehydes elongated by two carbon atoms. PMID:27490682

  9. Placental Fatty Acid Ethyl Esters Are Elevated with Maternal Alcohol Use in Pregnancies Complicated by Prematurity

    PubMed Central

    Gauthier, Theresa W.; Mohan, Sowmya S.; Gross, Teresa S.; Harris, Frank L.; Guidot, David M.; Brown, Lou Ann S.

    2015-01-01

    The accumulation of fatty acid ethyl esters (FAEEs) in meconium of term newborns has been described as one potential biomarker of maternal alcohol use during pregnancy. FAEEs accumulate in multiple alcohol-exposed fetal tissues and in the placenta. Limited research has focused on the identification of the premature newborn exposed to alcohol in utero. We hypothesized that maternal alcohol use occurs in a significant proportion of premature deliveries and that this exposure can be detected as elevated placental FAEEs. The goals of this study were to 1) determine the prevalence of maternal alcohol use in the premature newborn and 2) investigate whether placental FAEEs could identify those newborns with fetal alcohol exposure. This prospective observational study evaluated 80 placentas from 80 women after premature delivery. Subjects were interviewed for alcohol intake and placental FAEEs were quantified via GC/MS. Receiver Operator Characteristic (ROC) Curves were generated to evaluate the ability of placental FAEEs to predict maternal drinking during pregnancy. Adjusted ROC curves were generated to adjust for gestational age, maternal smoking, and illicit drug use. 30% of the subjects admitted to drinking alcohol during pregnancy and approximately 14% answered questions indicative of problem drinking (designated AUDIT+). The specific FAEEs ethyl stearate and linoleate, as well as combinations of oleate + linoleate + linolenate (OLL) and of OLL + stearate, were significantly (p<0.05) elevated in placentas from AUDIT+ pregnancies. Adjusted ROC Curves generated areas under the curve ranging from 88–93% with negative predictive values of 97% for AUDIT+ pregnancies. We conclude that nearly one third of premature pregnancies were alcohol-exposed, and that elevated placental FAEEs hold great promise to accurately determine maternal alcohol use, particularly heavy use, in pregnancies complicated by premature delivery. PMID:25978403

  10. Molecular characterization of the fatty alcohol oxidation pathway for wax-ester mobilization in germinated jojoba seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jojoba (Simmondsia chinensis) is the only plant species known to use liquid wax esters (WE) as a primary seed storage reserve. Upon germination, WE hydrolysis releases very long-chain fatty alcohols, which must be oxidised to fatty acids by the sequential action of a fatty alcohol oxidase (FAO) and ...

  11. 40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6477 Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with...

  12. 40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6477 Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with...

  13. 40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6477 Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with...

  14. 40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6477 Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with...

  15. 40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6477 Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with...

  16. Effect of Alcohol Structure on the Optimum Condition for Novozym 435-Catalyzed Synthesis of Adipate Esters

    PubMed Central

    Abdul Rahman, Mohd Basyaruddin; Chaibakhsh, Naz; Basri, Mahiran

    2011-01-01

    Immobilized Candida antarctica lipase B, Novozym 435, was used as the biocatalyst in the esterification of adipic acid with four different isomers of butanol (n-butanol, sec-butanol, iso-butanol, and tert-butanol). Optimum conditions for the synthesis of adipate esters were obtained using response surface methodology approach with a four-factor-five-level central composite design concerning important reaction parameters which include time, temperature, substrate molar ratio, and amount of enzyme. Reactions under optimized conditions has yielded a high percentage of esterification (>96%) for n-butanol, iso-butanol, and sec-butanol, indicating that extent of esterification is independent of the alcohol structure for primary and secondary alcohols at the optimum conditions. Minimum reaction time (135 min) for achieving maximum ester yield was obtained for iso-butanol. The required time for attaining maximum yield and also the initial rates in the synthesis of di-n-butyl and di-sec-butyl adipate were nearly the same. Immobilized Candida antarctica lipase B was also capable of esterifying tert-butanol with a maximum yield of 39.1%. The enzyme is highly efficient biocatalyst for the synthesis of adipate esters by offering a simple production process and a high esterification yield. PMID:22389769

  17. Contamination of phthalate esters, organochlorine pesticides and polybrominated diphenyl ethers in agricultural soils from the Yangtze River Delta of China.

    PubMed

    Sun, Jianteng; Pan, Lili; Zhan, Yu; Lu, Hainan; Tsang, Daniel C W; Liu, Wenxin; Wang, Xilong; Li, Xiangdong; Zhu, Lizhong

    2016-02-15

    To reveal the pollution status associated with rapid urbanization and economic growth, extensive areas of agricultural soils (approximately 45,800 km(2)) in the Yangtze River Delta of China were investigated with respect to selected endocrine disruptor compounds (EDCs), including phthalate esters (PAEs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). The residues of sum of 15 PAEs, sum of 15 OCPs and sum of 13 PBDEs were in the range of 167-9370 ng/g, 1.0-3520 ng/g, and <1.0-382 ng/g, respectively. The OCPs residuals originated from both historical usage and recent input. Agricultural plastic film was considered to be an important source of PAEs. Discharge from furniture industry was potential major source of PBDEs in this region. The selected pollutants showed quite different spatial distributions within the studied region. It is worth noting that much higher concentrations of the EDCs were found on the borders between Shanghai and the two neighboring provinces, where agriculture and industry developed rapidly in recent years. Contaminants from both agricultural and industrial activities made this area a pollution hotspot, which should arouse more stringent regulation to safeguard the environment and food security. PMID:26674696

  18. Photodynamic Therapy With Hyperbranched Poly(Ether-Ester) Chlorin(e6) Nanoparticles On Human Tongue Carcinoma Cal-27 Cells

    PubMed Central

    Li, Pingping; Zhou, Guoyu; Zhu, Xinyuan; Li, Guolin; Yan, Peng; Shen, Linyue; Xu, Qin; Hamblin, Michael R

    2011-01-01

    Background Hyperbranched polymers represent a new class of drug delivery vehicle that can be used to prepare nanoparticles with uniform size distribution. Methods In this study we prepared covalent conjugates between the photosensitizer chlorin(e6) and hyperbranched poly(ether-ester), HPEE. HPEE-ce6 nanoparticles were synthesized by carbodiimide-mediated reaction between HPEE and ce6, and characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), and transmission electron microscopy (TEM). The uptake and phototoxicity of HPEE-ce6 nanoparticles towards human oral tongue cancer CAL-27 cells was detected by confocal laser scanning microscopy (CLSM) and MTT assay respectively. Results The absorption peak of HPEE-ce6 nanoparticles was red-shifted 12-nm compared with ce6, and TEM showed uniform nanoparticles with a diameter of 50-nm. HPEE-ce6 nanoparticles were taken up by CAL-27 cells after 4 hour incubation and localized in the cytoplasm. The MTT assay showed a significantly (P<0.05) higher phototoxicity compared to free ce6 after 12 J/cm2 of 660-nm laser illumination. Conclusions This is the first time to our knowledge that hyperbranched polymers have been used in PDT drug delivery. PMID:22369732

  19. A poly(ether-ester) copolymer for the preparation of nanocarriers with improved degradation and drug delivery kinetics.

    PubMed

    Gagliardi, M; Bertero, A; Bardi, G; Bifone, A

    2016-02-01

    This paper reports the synthesis and the physicochemical, functional and biological characterisations of nanocarriers made of a novel di-block biodegradable poly(ether-ester) copolymer. This material presents tunable, fast biodegradation rates, but its products are less acidic than those of other biosorbable polymers like PLGA, thus presenting a better biocompatibility profile and the possibility to carry pH-sensitive payloads. A method for the production of monodisperse and spherical nanoparticles is proposed; drug delivery kinetics and blood protein adsorption were measured to evaluate the functional properties of these nanoparticles as drug carriers. The copolymer was labelled with a fluorescent dye for internalisation tests, and rhodamine B was used as a model cargo to study transport and release inside cultured cells. Biological tests demonstrated good cytocompatibility, significant cell internalisation and the possibility to vehiculate non-cell penetrating moieties into endothelial cells. Taken together, these results support the potential use of this nanoparticulate system for systemic administration of drugs. PMID:26652400

  20. High octane ethers from synthesis gas-derived alcohols. Final technical report, September 25, 1990--December 24, 1993

    SciTech Connect

    Klier, K.; Herman, R.G.

    1994-05-01

    The objective of the research was to develop the methodology for the catalytic synthesis of ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from alcohol mixtures that are rich in methanol and 2-methyl-1-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The last stage of the synthesis involves direct coupling of synthesis gas-derived methanol and isobutanol that has been previously demonstrated by us to occur over superacid catalysts to yield MIBE and smaller amounts of MTBE at moderate pressures and a mixture of methanol and isobutene at low pressures. A wide range of organic resin catalysts and inorganic oxide and zeolite catalysts have been investigated for activity and selectivity in directly coupling alcohols, principally methanol and isobutanol, to form ethers and in the dehydration of isobutanol to isobutene in the presence of methanol. All of these catalysts are strong acids, and it was found that the organic and inorganic catalysts operate in different, but overlapping, temperature ranges, i.e. mainly 60--120{degrees}C for the organic resins and 90--175{degrees}C for the inorganic catalysts. For both types of catalysts, the presence of strong acid centers is required for catalytic activity, as was demonstrated by lack of activity of fully K{sup +} ion exchanged Nafion resin and zirconia prior to being sulfated by treatment with sulfuric acid.

  1. Main-group compounds selectively oxidize mixtures of methane, ethane, and propane to alcohol esters.

    PubMed

    Hashiguchi, Brian G; Konnick, Michael M; Bischof, Steven M; Gustafson, Samantha J; Devarajan, Deepa; Gunsalus, Niles; Ess, Daniel H; Periana, Roy A

    2014-03-14

    Much of the recent research on homogeneous alkane oxidation has focused on the use of transition metal catalysts. Here, we report that the electrophilic main-group cations thallium(III) and lead(IV) stoichiometrically oxidize methane, ethane, and propane, separately or as a one-pot mixture, to corresponding alcohol esters in trifluoroacetic acid solvent. Esters of methanol, ethanol, ethylene glycol, isopropanol, and propylene glycol are obtained with greater than 95% selectivity in concentrations up to 1.48 molar within 3 hours at 180°C. Experiment and theory support a mechanism involving electrophilic carbon-hydrogen bond activation to generate metal alkyl intermediates. We posit that the comparatively high reactivity of these d(10) main-group cations relative to transition metals stems from facile alkane coordination at vacant sites, enabled by the overall lability of the ligand sphere and the absence of ligand field stabilization energies in systems with filled d-orbitals. PMID:24626925

  2. EVALUATION OF METHYL TERT-BUTYL ETHER (MTBE) AS AN INTERFERENCE ON COMMERCIAL BREATH-ALCOHOL ANALYZERS

    EPA Science Inventory

    Anecdotal reports suggest that high environmental or occupational exposures to the fuel oxygenate methyl tert-butyl ether (MTBE) may result in breath concentrations that are sufficiently elevated to cause a false positive on commercial breath-alcohol analyzers. We evaluated th...

  3. Hydrosilylation of Polymethylhydrogenosiloxanes in the Presence of Functional Molecules Such as Amines, Esters or Alcohols

    NASA Astrophysics Data System (ADS)

    Binet, Corinne; Dumont, Matthieu; Fitremann, Juliette; Gineste, Stéphane; Laurent, Elisabeth; Marty, Jean-Daniel; Mauzac, Monique; Mingotaud, Anne-Françoise; Moukarzel, Waêl; Palaprat, Guillaume; Zadoina, Lacramioara

    This article presents an overview of the methods used in our laboratory to successfully perform hydrosilylation reactions on polymethylhydrogenosiloxane polymer in the presence of several functional molecules, such as esters, acids, amines, alcohols or carbamates. The used catalysts are platinum based homogeneous systems. In each case, experimental parameters such as choice of catalyst, catalyst/Si-H functions ratio, temperature have been examined. Also, a detailed kinetic study was performed in the case of liquid crystal molecules in order to better characterize the system.

  4. High octane ethers from synthesis gas-derived alcohols. [Methyl isobutyl ether(MIBE) and methyl tertiary butyl ether(MTBE)

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.A.; Feeley, O.C.

    1993-02-01

    The testing of strongly acidic catalysts for the conversion of a mixture of methanol and isobutanol to ethers and hydrocarbons was continued. Under standardized test conditions the catalysts tested this quarter were: phosphotungstic acid supported on zirconia (PW[sub 12]/ZrO[sub 2]), niobic acid'' (Nb[sub 2]O[sub 5]xH[sub 2]0), and an iron and manganese doped sulfate-modified zirconia (Fe/Mn/ZrO[sub 2]/SO[sub 4][sup [minus]2]). The overall activity of these catalysts followed the order of Fe/Mn/ZrO[sub 2]/SO[sub 4][sup [minus]2] > PW[sub 12]/ZrO[sub 2] > Nb[sub 2]O[sub 5]xH[sub 2]0 with the Fe/Mn/ZrO[sub 2]/SO[sub 4][sup [minus]2] catalyst approaching ZrO[sub 2]/SO[sub 4][sup [minus]2] in both activity and selectivity for isobutene production. The effect of the presence of water on the reaction of methanol and isobutanol over ZrO[sub 2]/SO[sub 4][sup [minus]2] was determined to be insignificant. At 157[degrees]C and a feed of 2/1 molar ratio methanol/isobutanol, the production of isobutene was unaffected by the addition of 0.05and 0.10 parts of water to the 2/1 alcohol feed. Surface areas have been determined for Fe/Mn/ZrO[sub 2]/SO[sub 4][sup [minus]2] niobic acid, and phosphotungstic acid on silica. After calcination, the surface area for Fe/Mn/ZrO[sub 2]/SO[sub 4][sup [minus]2] was found to be 83 M2 /g. Niobic acid and phosphotungstic acid on silica (PW[sub 12]/SiO[sub 2]) were found to have surface areas of 118 and 218 m[sup 2]/g, respectively. [sup 1]H NMR was used to determine if and how much 1-butene was present as a product when isobutanol is dehydrated over sulfate-modified zirconia. It was found to be present in small amounts, [le]3% of the product stream.

  5. Interstellar Alcohols

    NASA Technical Reports Server (NTRS)

    Charnley, S. B.; Kress, M. E.; Tielens, A. G. G. M.; Millar, T. J.

    1995-01-01

    We have investigated the gas-phase chemistry in dense cores where ice mantles containing ethanol and other alcohols have been evaporated. Model calculations show that methanol, ethanol, propanol, and butanol drive a chemistry leading to the formation of several large ethers and esters. Of these molecules, methyl ethyl ether (CH3OC2H5) and diethyl ether (C2H5)2O attain the highest abundances and should be present in detectable quantities within cores rich in ethanol and methanol. Gas-phase reactions act to destroy evaporated ethanol and a low observed abundance of gas-phase C,H,OH does not rule out a high solid-phase abundance. Grain surface formation mechanisms and other possible gas-phase reactions driven by alcohols are discussed, as are observing strategies for the detection of these large interstellar molecules.

  6. Substitution of ether linkage for ester bond in phospholipids increases permeability of bilayer lipid membrane for SkQ1-type penetrating cations.

    PubMed

    Il'yasova, T M; Rokitskaya, T I; Severina, I I; Antonenko, Y N; Skulachev, V P

    2012-09-01

    Using dialkylphospholipid (diphytanyl phosphatidylcholine) instead of the conventional diacylphospholipid (diphytanoyl phosphatidylcholine) in planar lipid bilayer membranes (BLM) led to an increase in the diffusion potential of the penetrating cation plastoquinonyl-decyl-triphenylphosphonium (SkQ1), making it close to the Nernst value, and accelerated translocation of SkQ1 across the BLM as monitored by the kinetics of a decrease in the transmembrane electric current after applying a voltage (current relaxation). The consequences of changing from an ester to an ether linkage between the head groups and the hydrocarbon chains are associated with a substantial reduction in the membrane dipole potential known to originate from dipoles of tightly bound water molecules and carbonyl groups in ester bonds. The difference in the dipole potential between BLM formed of the ester phospholipid and that of the ether phospholipid was estimated to be 100 mV. In the latter case, suppression of SkQ1-mediated proton conductivity of the BLM was also observed. PMID:23157264

  7. Hydroxyalkylation with. cap alpha. -hydroperoxydiazenes. Alcohols from olefins and carbonyl compounds from enol ethers

    SciTech Connect

    Osei-Twum, E.Y.; McCallion, D.; Nazran, A.S.; Panicucci, R.; Risbood, P.A.; Warkentin, J.

    1984-01-27

    Alkyl(1-hydroperoxy-1-methylethyl)diazenes 2a-C((CH/sub 3/)/sup 2/C(OOH)N=NR: a,R =CH/sub 2/CH/sub 2/CN; c,R = CH/sub 2/CH(CH/sub 3/)CN; d,R = CH/sub 2/CH/sub 2/OCH/sub 3/; e,r =CH/sub 2/CH/sub 2/OC/sub 6/H/sub 5/; f,R = CH/sub 2/CH/sub 2/CH/sub 2/OC/sub 6/H/sub 5/)) were prepared in solution by autoxidation of the corresponding hydrazones of acetone. Thermolysis of the diazenes at 50-80/sup 0/C in alkenes leads to alcohols. For example, 2b decomposes in 1,1-diphenylethene to afford 5-hydroxy-5,5-yield. Thermolysis of a diazene 2 in an enol ether solvent leads to an aldehyde or a ketone. Thus, 2a decomposes in 1-ethoxyethene and in 2-methoxypropene to afford, respective, 4,4,4-trifluorobutanol and 5,5,5-trifluoro-intermediates and radical chain hydroxyalkylation of alkene double bonds. In one chain-propagating step, R., generated from 2, adds to the alkene. The adduct radical so formed propagates by inducing decomposition of 2 by attack at hydroxyl oxygen. According to this mechanism, inital products from enol ethers are hemiacetals or hemiketals which do not survive the reaction conditions but decompose to the corresponding carbonyl compounds. Preliminary evidence for this mechanism is presented.

  8. Studies of a pyridino-crown ether-based chiral stationary phase on the enantioseparation of biogenic chiral aralkylamines and α-amino acid esters by high-performance liquid chromatography.

    PubMed

    Lévai, Sándor; Németh, Tamás; Fődi, Tamás; Kupai, József; Tóth, Tünde; Huszthy, Péter; Balogh, György Tibor

    2015-11-10

    This paper reports the enantioseparation ability of a pyridino-18-crown-6 ether-based chiral stationary phase [(S,S)-CSP-1]. The enantiomeric discrimination of chiral stationary phase (S,S)-CSP-1 was evaluated by HPLC using the mixtures of enantiomers of various protonated primary aralkylamines [1-phenylethylamine hydrogen perchlorate (PEA), 2,3-dihydro-1H-inden-1-amine (1-aminoindan), 2,2'-(1,2-diaminoethane-1,2-diyl) diphenol (HPEN)] and perchlorate salts of α-amino acid esters [alanine benzyl ester (Ala-OBn), phenylalanine benzyl ester (Phe-OBn), phenylalanine methyl ester (Phe-OMe), phenylglycine methyl ester (PhGly-OMe), glutamic acid dibenzyl ester (Glu-diOBn), and valine benzyl ester (Val-OBn)]. The best enantioseparation was achieved in the case of PEA. The high enantioselectivity was rationalized by the strong π-π interaction of the extended π system of the aryl-substituted pyridine unit. PMID:26218505

  9. Immobilized Rhizopus oryzae lipase catalyzed synthesis of palm stearin and cetyl alcohol wax esters: Optimization by Response Surface Methodology

    PubMed Central

    2011-01-01

    Background Waxes are esters of long-chain fatty acids and long-chain alcohols. Their principal natural sources are animals (sperm whale oil) and vegetables (jojoba) which are expensive and not easily available. Wax esters synthesized by enzymatic transesterification, using palm stearin as raw material, can be considered as an alternative to natural ones. Results Palm stearin is a solid fraction obtained by fractionation of palm oil. Palm stearin was esterified with cetyl alcohol to produce a mixture of wax esters. A non-commercial immobilized lipase from Rhizopus oryzae was used as biocatalyst. Response surface methodology was employed to determine the effects of the temperature (30-50°C), the enzyme concentration (33.34-300 IU/mL), the alcohol/palm stearin molar ratio (3-7 mol/mol) and the substrate concentration (0.06-0.34 g/mL) on the conversion yield of palm stearin. Under optimal conditions (temperature, 30°C; enzyme concentration, 300 IU/mL; molar ratio 3 and substrate concentration 0.21 g/mL) a high conversion yield of 98.52% was reached within a reaction time of 2 h. Conclusions Response surface methodology was successfully applied to determine the optimum operational conditions for synthesis of palm stearin based wax esters. This study may provide useful tools to develop economical and efficient processes for the synthesis of wax esters. PMID:21682865

  10. Divergence in the Enzymatic Activities of a Tomato and Solanum pennellii Alcohol Acyltransferase Impacts Fruit Volatile Ester Composition.

    PubMed

    Goulet, Charles; Kamiyoshihara, Yusuke; Lam, Nghi B; Richard, Théo; Taylor, Mark G; Tieman, Denise M; Klee, Harry J

    2014-10-29

    Tomato fruits accumulate a diverse set of volatiles including multiple esters. The content of ester volatiles is relatively low in tomato fruits (Solanum lycopersicum) and far more abundant in the closely related species S. pennellii. There are also qualitative variations in ester content between the two species. We have previously shown that high expression of a non-specific esterase is critical for the low overall ester content of S. lycopersicum fruit relative to S. pennellii fruit. Here, we show that qualitative differences in ester composition are the consequence of divergence in enzymatic activity of a ripening-related alcohol acyltransferase (AAT1). The S. pennellii AAT1 is more efficient than the tomato AAT1 for all the alcohols tested. The two enzymes have differences in their substrates preferences that explain variations observed in the volatiles. Together, the results illustrate how two related species have evolved to precisely adjust their volatile content by modulating the balance of synthesis and degradation of esters. PMID:25355057

  11. Divergence in the enzymatic activities of a tomato and Solanum pennellii alcohol acyltransferase impacts fruit volatile ester composition.

    PubMed

    Goulet, Charles; Kamiyoshihara, Yusuke; Lam, Nghi B; Richard, Théo; Taylor, Mark G; Tieman, Denise M; Klee, Harry J

    2015-01-01

    Tomato fruits accumulate a diverse set of volatiles including multiple esters. The content of ester volatiles is relatively low in tomato fruits (Solanum lycopersicum) and far more abundant in the closely related species Solanum pennellii. There are also qualitative variations in ester content between the two species. We have previously shown that high expression of a non-specific esterase is critical for the low overall ester content of S. lycopersicum fruit relative to S. pennellii fruit. Here, we show that qualitative differences in ester composition are the consequence of divergence in enzymatic activity of a ripening-related alcohol acyltransferase (AAT1). The S. pennellii AAT1 is more efficient than the tomato AAT1 for all the alcohols tested. The two enzymes have differences in their substrate preferences that explain the variations observed in the volatiles. The results illustrate how two related species have evolved to precisely adjust their volatile content by modulating the balance of the synthesis and degradation of esters. PMID:25578279

  12. Ether- and alcohol-functionalized task-specific ionic liquids: attractive properties and applications.

    PubMed

    Tang, Shaokun; Baker, Gary A; Zhao, Hua

    2012-05-21

    In recent years, the designer nature of ionic liquids (ILs) has driven their exploration and exploitation in countless fields among the physical and chemical sciences. A fair measure of the tremendous attention placed on these fluids has been attributed to their inherent designer nature. And yet, there are relatively few examples of reviews that emphasize this vital aspect in an exhaustive or meaningful way. In this critical review, we systematically survey the physicochemical properties of the collective library of ether- and alcohol-functionalized ILs, highlighting the impact of ionic structure on features such as viscosity, phase behavior/transitions, density, thermostability, electrochemical properties, and polarity (e.g. hydrophilicity, hydrogen bonding capability). In the latter portions of this review, we emphasize the attractive applications of these functionalized ILs across a range of disciplines, including their use as electrolytes or functional fluids for electrochemistry, extractions, biphasic systems, gas separations, carbon capture, carbohydrate dissolution (particularly, the (ligno)celluloses), polymer chemistry, antimicrobial and antielectrostatic agents, organic synthesis, biomolecular stabilization and activation, and nanoscience. Finally, this review discusses anion-functionalized ILs, including sulfur- and oxygen-functionalized analogs, as well as choline-based deep eutectic solvents (DESs), an emerging class of fluids which can be sensibly categorized as semi-molecular cousins to the IL. Finally, the toxicity and biodegradability of ether- and alcohol-functionalized ILs are discussed and cautiously evaluated in light of recent reports. By carefully summarizing literature examples on the properties and applications of oxy-functional designer ILs up till now, it is our intent that this review offers a barometer for gauging future advances in the field as well as a trigger to spur further contemplation of these seemingly inexhaustible and

  13. Ether- and Alcohol-Functionalized Task-Specific Ionic Liquids: Attractive Properties and Applications

    PubMed Central

    Tang, Shaokun; Baker, Gary A.; Zhao, Hua

    2012-01-01

    In recent years, the designer nature of ionic liquids (ILs) has driven their exploration and exploitation in countless fields among the physical and chemical sciences. A fair measure of the tremendous attention placed on these fluids has been attributed to their inherent designer nature. And yet, there are relatively few examples of reviews which emphasize this vital aspect in an exhaustive or meaningful way. In this critical review, we systematically survey the physicochemical properties of the collective library of ether- and alcohol-functionalized ILs, highlighting the impact of ionic structure on features such as viscosity, phase behavior/transitions, density, thermostability, electrochemical properties, and polarity (e.g., hydrophilicity, hydrogen bonding capability). In the latter portions of this review, we emphasize the attractive applications of these functionalized ILs across a range of disciplines, including their use as electrolytes or functional fluids for electrochemistry, extractions, biphasic systems, gas separations, carbon capture, carbohydrate dissolution (particularly, the (ligno)celluloses), polymer chemistry, antimicrobial and antielectrostatic agents, organic synthesis, biomolecular stabilization and activation, and nanoscience. Finally, this review discusses anion-functionalized ILs, including sulfur- and oxygen-functionalized analogs, as well as choline-based deep eutectic solvents (DESs), an emerging class of fluids which can be sensibly categorized as semi-molecular cousins to the IL. Finally, the toxicity and biodegradability of ether- and alcohol-functionalized ILs are discussed and cautiously evaluated in light of recent reports. By carefully summarizing literature examples on the properties and applications of oxy-functional designer ILs up till now, it is our intent that this review offer a barometer for gauging future advances in the field as well as a trigger to spur further contemplation of these seemingly inexhaustible and

  14. Apple Aminoacid Profile and Yeast Strains in the Formation of Fusel Alcohols and Esters in Cider Production.

    PubMed

    Eleutério Dos Santos, Caroline Mongruel; Pietrowski, Giovana de Arruda Moura; Braga, Cíntia Maia; Rossi, Márcio José; Ninow, Jorge; Machado Dos Santos, Tâmisa Pires; Wosiacki, Gilvan; Jorge, Regina Maria Matos; Nogueira, Alessandro

    2015-06-01

    The amino acid profile in dessert apple must and its effect on the synthesis of fusel alcohols and esters in cider were established by instrumental analysis. The amino acid profile was performed in nine apple musts. Two apple musts with high (>150 mg/L) and low (<75 mg/L) nitrogen content, and four enological yeast strains, were used in cider fermentation. The aspartic acid, asparagine and glutamic acid amino acids were the majority in all the apple juices, representing 57.10% to 81.95%. These three amino acids provided a high consumption (>90%) during fermentation in all the ciders. Principal component analysis (PCA) explained 81.42% of data variability and the separation of three groups for the analyzed samples was verified. The ciders manufactured with low nitrogen content showed sluggish fermentation and around 50% less content of volatile compounds (independent of the yeast strain used), which were mainly 3-methyl-1-butanol (isoamyl alcohol) and esters. However, in the presence of amino acids (asparagine, aspartic acid, glutamic acid and alanine) there was a greater differentiation between the yeasts in the production of fusel alcohols and ethyl esters. High contents of these aminoacids in dessert apple musts are essential for the production of fusel alcohols and most of esters by aromatic yeasts during cider fermentation. PMID:25920613

  15. Hyperbranched exopolysaccharide-enhanced foam properties of sodium fatty alcohol polyoxyethylene ether sulfate.

    PubMed

    Deng, Quanhua; Li, Haiping; Sun, Haoyang; Sun, Yange; Li, Ying

    2016-05-01

    The foam properties, such as the foamability, foam stability, drainage, coalescence and bulk rheology, of aqueous solutions containing an eco-friendly exopolysaccharide (EPS) secreted by a deep-sea mesophilic bacterium, Wangia profunda SM-A87, and an anionic surfactant, sodium fatty alcohol polyoxyethylene ether sulfate (AES), were studied. Both the foamability and foam stability of the EPS/AES solutions are considerably higher than those of single AES solutions, even at very low AES concentrations, although pure EPS solutions cannot foam. The improved foamability and foam stability arise from the formation of the EPS/AES complex via hydrogen bonds at the interfaces. The synergism between the EPS and AES decreases the surface tension, increases the interfacial elasticity and water-carrying capacity, and suppresses the coalescence and collapse of the foams. The EPS/AES foams are more salt-resistant than the AES foams. This work provides not only a new eco-friendly foam with great potential for use in enhanced oil recovery and health-care products but also useful guidance for designing other environmentally friendly foam systems that exhibit high performance. PMID:26852104

  16. Low cost hydrogen/novel membrane technology for hydrogen separation from synthesis gas, Phase 1. [Poly(etherimide) and poly(ether-ester-amide) membranes

    SciTech Connect

    Not Available

    1986-01-01

    During the last quarter several high performance membranes for the separation of hydrogen from nitrogen, carbon monoxide, hydrogen sulfide and carbon dioxide. The heat-resistant resin poly(etherimide) has been selected as the polymer with the most outstanding properties for the separation of hydrogen from nitrogen and carbon monoxide. Flat sheet and hollow fiber poly(etherimide) membranes have been prepared and evaluated with pure gases and gas mixtures at elevated pressures and temperatures. Multilayer composite poly(ether-ester-amide) membranes were also developed. These membranes are useful for the separation of carbon dioxide and hydrogen sulfide hydrogen. They have very high selectivities and extremely high normalized carbon dioxide and hydrogen sulfide fluxes. Separation of carbon dioxide/hydrogen streams is a key problem in hydrogen production from coal. The development of the two membranes now gives us two approaches to separate these gas streams, depending on the stream's composition. If the stream contains small quantities of hydrogen, the hydrogen- permeable poly(etherimide) membrane would be used to produce a hydrogen-enriched permeate. If the stream contains small quantities of carbon dioxide or hydrogen sulfide, the poly(ether-ester-amide) membrane would be used to produce a carbon dioxide/hydrogen sulfide-free, hydrogen-enriched residue stream. 6 fig., 4 tabs.

  17. High octane ethers from synthesis gas-derived alcohols. Quarterly technical progress report, October--December 1992, Revision 1

    SciTech Connect

    Klier, K.; Herman, R.G.; Johansson, M.A.; Feeley, O.C.

    1993-04-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE) directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The testing of strongly acidic catalysts for the conversion of a mixture of methanol and isobutanol to ethers and hydrocarbons was continued. Under standardized test conditions the catalysts tested this quarter were: phosphotungstic acid supported on zirconia (PW{sub 12}/ZrO{sub 2}), ``niobic acid`` (Nb{sub 2}O{sub 5}{center_dot}xH{sub 2}O), and an iron and manganese doped sulfate-modified zirconia (Fe/Mn/ZrO{sub 2}/SO{sub 4}{sup 2{minus}}). The overall activity of these catalysts followed the order of Fe/Mn/ZrO{sub 2}/SO{sub 4}{sup 2{minus}} > PW{sub 12}/ZrO{sub 2} >Nb{sub 2}O{sub 5}{center_dot}xH{sub 2}O With the Fe/Mn/ZrO{sub 2}/SO{sub 4}{sup 2{minus}} catalyst approaching ZrO{sub 2}/SO{sub 4}{sup 2{minus}} in both activity and selectivity for isobutene production. The effect of the presence of water on the reaction of methanol and isobutanol over ZrO{sub 2}/SO{sub 4}{sup 2{minus}} was determined to be insignificant under the reaction conditions investigated.

  18. Composition-explicit distillation curves of diesel fuel with glycol ether and glycol ester oxygenates: fuel analysis metrology to enable decreased particulate emissions.

    PubMed

    Smith, Beverly L; Ott, Lisa S; Bruno, Thomas J

    2008-10-15

    We recently introduced several important improvements in the measurement of distillation curves of complex fluids. The modifications to the classical measurement provide for (1) a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state, (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development, (4) consistency with a century of historical data, (5) an assessment of the energy content of each distillate fraction, (6) trace chemical analysis of each distillate fraction, and (7) corrosivity assessment of each distillate fraction. We have applied the new method to the measurement of rocket propellant, gasolines, jet fuels, and hydrocarbon crude oils. In this paper we presentthe application of the technique to representative diesel fuel and mixtures of diesel fuel with some of the more promising oxygenating agents; namely, the glycol ethers and glycol esters: tri(propylene glycol) methyl ether (TPM), dibutyl maleate (DBM), and an 80/ 20 (vol/vol) mixture of diethylene glycol methyl ether (DGME) + 1,2-dimethoxyethane (DME) a mixture often referred to as Cetaner. We present not only the distillation curves but also a chemical characterization of each fraction, and discuss the contrasts between the various mixtures. The measurements are significant as an environmental design tool for decreased particulate emissions. PMID:18983093

  19. Yeast: the soul of beer's aroma--a review of flavour-active esters and higher alcohols produced by the brewing yeast.

    PubMed

    Pires, Eduardo J; Teixeira, José A; Brányik, Tomás; Vicente, António A

    2014-03-01

    Among the most important factors influencing beer quality is the presence of well-adjusted amounts of higher alcohols and esters. Thus, a heavy body of literature focuses on these substances and on the parameters influencing their production by the brewing yeast. Additionally, the complex metabolic pathways involved in their synthesis require special attention. More than a century of data, mainly in genetic and proteomic fields, has built up enough information to describe in detail each step in the pathway for the synthesis of higher alcohols and their esters, but there is still place for more. Higher alcohols are formed either by anabolism or catabolism (Ehrlich pathway) of amino acids. Esters are formed by enzymatic condensation of organic acids and alcohols. The current paper reviews the up-to-date knowledge in the pathways involving the synthesis of higher alcohols and esters by brewing yeasts. Fermentation parameters affecting yeast response during biosynthesis of these aromatic substances are also fully reviewed. PMID:24384752

  20. Metabolic basis of ethylene glycol monobutyl ether (2-butoxyethanol) toxicity: role of alcohol and aldehyde dehydrogenases

    SciTech Connect

    Ghanayem, B.I.; Burka, L.T.; Matthews, H.B.

    1987-07-01

    2-Butoxyethanol (BE) is a massively produced glycol ether of which more than 230 million pounds was produced in the United States in 1983. It is extensively used in aerosols and cleaning agents intended for household use. This creates a high potential for human exposure during its manufacturing and use. A single exposure of rats to BE causes severe hemolytic anemia accompanied by secondary hemoglobinuria as well as liver and kidney damage. Butoxyacetic acid (BAA) was earlier identified as a urinary metabolite of BE. In addition, we have recently identified two additional urinary metabolites of BE, namely, BE-glucuronide and BE-sulfate conjugates. The current studies were undertaken to investigate the metabolic basis of BE-induced hematotoxicity in male F344 rats. Treatment of rats with pyrazole (alcohol dehydrogenase inhibitor) protected rats against BE-induced hematotoxicity and inhibited BE metabolism to BAA. Pyrazole inhibition of BE metabolism to BAA was accompanied by increased BE metabolism to BE-glucuronide and BE-sulfate as determined by quantitative high-performance liquid chromatography analysis of BE metabolites in urine. There was approximately a 10-fold decrease in the ratio of BAA to BE-glucuronide + BE-sulfate in the urine of rats treated with pyrazole + BE compared to rats treated with BE alone. Pretreatment of rats with cyanamide (aldehyde dehydrogenase inhibitor) also significantly protected rats against BE-induced hematotoxicity and modified BE metabolism in a manner similar to that caused by pyrazole. Administration of equimolar doses of BE, the metabolic intermediate butoxyacetaldehyde, or the ultimate metabolite BAA caused similar hematotoxic effects. Cyanamide also protected rats against butoxyacetaldehyde-induced hematotoxicity.

  1. Optimization of reactive simulated moving bed systems with modulation of feed concentration for production of glycol ether ester.

    PubMed

    Agrawal, Gaurav; Oh, Jungmin; Sreedhar, Balamurali; Tie, Shan; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

    2014-09-19

    In this article, we extend the simulated moving bed reactor (SMBR) mode of operation to the production of propylene glycol methyl ether acetate (DOWANOL™ PMA glycol ether) through the esterification of 1-methoxy-2-propanol (DOWANOL™ PM glycol ether) and acetic acid using AMBERLYST™ 15 as a catalyst and adsorbent. In addition, for the first time, we integrate the concept of modulation of the feed concentration (ModiCon) to SMBR operation. The performance of the conventional (constant feed) and ModiCon operation modes of SMBR are analyzed and compared. The SMBR processes are designed using a model based on a multi-objective optimization approach, where a transport dispersive model with a linear driving force for the adsorption rate has been used for modeling the SMBR system. The adsorption equilibrium and kinetics parameters are estimated from the batch and single column injection experiments by the inverse method. The multiple objectives are to maximize the production rate of DOWANOL™ PMA glycol ether, maximize the conversion of the esterification reaction and minimize the consumption of DOWANOL™ PM glycol ether which also acts as the desorbent in the chromatographic separation. It is shown that ModiCon achieves a higher productivity by 12-36% over the conventional operation with higher product purity and recovery. PMID:25127692

  2. 40 CFR 721.6475 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl polycarboxylic acids, esters... Significant New Uses for Specific Chemical Substances § 721.6475 Alkyl polycarboxylic acids, esters with... chemical substances identified generically as alkyl polycarboxylic acids, esters with ethoxylated...

  3. 40 CFR 721.6475 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl polycarboxylic acids, esters... Significant New Uses for Specific Chemical Substances § 721.6475 Alkyl polycarboxylic acids, esters with... chemical substances identified generically as alkyl polycarboxylic acids, esters with ethoxylated...

  4. Kinetics of enzymatic synthesis of liquid wax ester from oleic acid and oleyl alcohol.

    PubMed

    Radzi, Salina Mat; Mohamad, Rosfarizan; Basri, Mahiran; Salleh, Abu Bakar; Ariff, Arbakariya; Rahman, Mohammad Basyaruddin Abdul; Rahman, Raja Noor Zaliha Raja Abdul

    2010-01-01

    The kinetics of wax ester synthesis from oleic acid and oleyl alcohol using immobilized lipase from Candida antartica as catalyst was studied with different types of impeller (Rushton turbine and AL-hydrofoil) to create different mixing conditions in 2l stirred tank reactor. The effects of catalyst concentration, reaction temperature, and impeller tip speed on the synthesis were also evaluated. Rushton turbine impeller exhibited highest conversion rate at lower impeller tip speed as compared to AL-hydrofoil impeller. A second-order reversible kinetic model from single progress curve for the prediction of fractional conversion at given reaction time was proposed and the corresponding kinetic parameter values were calculated by non-linear regression method. The results from the simulation using the proposed model showed satisfactory agreement with the experimental data. Activation energy shows a value of 21.77 Kcal/mol. The thermodynamic parameters of the process, enthalpy and entropy, were 21.15 Kcal/mol and 52.07 cal/mol.K, respectively. PMID:20124754

  5. Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols.

    PubMed

    Rossi, Bianca; Pastori, Nadia; Prosperini, Simona; Punta, Carlo

    2015-01-01

    Following an optimized multicomponent procedure, an aryl amine, a ketone, and a cyclic ether or an alcohol molecule are assembled in a one-pot synthesis by nucleophilic radical addition of ketyl radicals to ketimines generated in situ. The reaction occurs under mild conditions by mediation of the TiCl4/Zn/t-BuOOH system, leading to the formation of quaternary β-amino-ethers and -alcohols. The new reaction conditions guarantee good selectivity by preventing the formation of secondary products. The secondary products are possibly derived from a competitive domino reaction, which involves further oxidation of the ketyl radicals. PMID:25670994

  6. Hydrogenation of esters to alcohols with a well-defined iron complex.

    PubMed

    Werkmeister, Svenja; Junge, Kathrin; Wendt, Bianca; Alberico, Elisabetta; Jiao, Haijun; Baumann, Wolfgang; Junge, Henrik; Gallou, Fabrice; Beller, Matthias

    2014-08-11

    We present the first base-free Fe-catalyzed ester reduction applying molecular hydrogen. Without any additives, a variety of carboxylic acid esters and lactones were hydrogenated with high efficiency. Computations reveal an outer-sphere mechanism involving simultaneous hydrogen transfer from the iron center and the ligand. This assumption is supported by NMR experiments. PMID:24890043

  7. FTIR studies of hydrogen bonding between α,β-unsaturated esters and alcohols

    NASA Astrophysics Data System (ADS)

    Tonge, P. J.; Fausto, R.; Carey, P. R.

    1996-06-01

    The enthalpy (and entropy) of hydrogen bond formation has been measured between the ester carbonyl groups of the two α,β-unsaturated esters thienylacryloyl (TAOMe) and 5-methylthienylacryloyl (5MeTAOMe) methyl ester and the hydrogen bond donors ethanol, phenol and 3,5-dichlorophenol in CCl 4. For the esters, the hydrogen bonding strengths were measured by quantitating the amount of bound and unbound donor, using the OH stretching region, as a function of temperature and applying the van't Hoff equation. The decrease in νCO of the ester carbonyl group upon hydrogen bond formation ΔνCO has also been measured and correlated with the enthalpy of hydrogen bond formation. A linear correlation is observed between the enthalpy of hydrogen bond formation - ΔH and ΔνCO, with - ΔH = 1.36 ΔνCO - 16.1, where ΔH is measured in kJ mol -1 and Δν in cm -1. Comparison with data for other carbonyl acceptor compounds indicates that the carbonyl group of the above α,β-unsaturated esters is more readily polarized than the carbonyl group of saturated esters or ketones. The quantitative relationship between - ΔH and ΔνCO derived here has been used to determine the change in the enthalpy of hydrogen bond formation between substrate and enzyme groups in a series of acylserine proteases.

  8. Molecular Characterization of the Fatty Alcohol Oxidation Pathway for Wax-Ester Mobilization in Germinated Jojoba Seeds1[W

    PubMed Central

    Rajangam, Alex S.; Gidda, Satinder K.; Craddock, Christian; Mullen, Robert T.; Dyer, John M.; Eastmond, Peter J.

    2013-01-01

    Jojoba (Simmondsia chinensis) is the only plant species known to use liquid wax esters (WEs) as a primary seed storage reserve. Upon germination, WE hydrolysis releases very-long-chain fatty alcohols, which must be oxidized to fatty acids by the sequential action of a fatty alcohol oxidase (FAO) and a fatty aldehyde dehydrogenase (FADH) before they can be β-oxidized. Here, we describe the cloning and characterization of genes for each of these two activities. Jojoba FAO and FADH are 52% and 68% identical to Arabidopsis (Arabidopsis thaliana) FAO3 and ALDH3H1, respectively. The genes are expressed most strongly in the cotyledons of jojoba seedlings following germination, but transcripts can also be detected in vegetative tissues. Proteomic analysis indicated that the FAO and FADH proteins can be detected on wax bodies, but they localized to the endoplasmic reticulum when they were expressed as amino-terminal green fluorescent protein fusions in tobacco (Nicotiana tabacum) leaves. Recombinant jojoba FAO and FADH proteins are active on very-long-chain fatty alcohol and fatty aldehyde substrates, respectively, and have biochemical properties consistent with those previously reported in jojoba cotyledons. Coexpression of jojoba FAO and FADH in Arabidopsis enhanced the in vivo rate of fatty alcohol oxidation more than 4-fold. Taken together, our data suggest that jojoba FAO and FADH constitute the very-long-chain fatty alcohol oxidation pathway that is likely to be necessary for efficient WE mobilization following seed germination. PMID:23166353

  9. HIGH LEVELS OF MONOAROMATIC COMPOUNDS LIMIT THE USE OF SOLID-PHASE MICROEXTRACTION OF METHYL TERTIARY BUTYL ETHER AND TERTIARY BUTYL ALCOHOL

    EPA Science Inventory

    Recently, two papers reported the use of solid-phase microextraction (SPME) with polydimethylsiloxane(PDMS)/Carboxen fibers to determine trace levels of methyl tertiary butyl ether (MTBE) and tertiary butyl alcohol (tBA) in water. Attempts were made to apply this technique to th...

  10. Widespread occurrence of bisphenol A diglycidyl ethers, p-hydroxybenzoic acid esters (parabens), benzophenone type-UV filters, triclosan, and triclocarban in human urine from Athens, Greece.

    PubMed

    Asimakopoulos, Alexandros G; Thomaidis, Nikolaos S; Kannan, Kurunthachalam

    2014-02-01

    Biomonitoring of human exposure to bisphenol A diglycidyl ethers (BADGEs; resin coating for food cans), p-hydroxybenzoic acid esters (parabens; preservatives), benzophenone-type UV filters (BP-UV filters; sunscreen agents), triclosan (TCS; antimicrobials), and triclocarban (TCC; antimicrobials) has been investigated in western European countries and North America. Nevertheless, little is known about the exposure of Greek populations to these environmental chemicals. In this study, 100 urine samples collected from Athens, Greece, were analyzed by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the determination of total concentrations of five derivatives of BADGEs, six parabens and their metabolite (ethyl-protocatechuate), five derivatives of BP-UV filters, TCS, and TCC. Urinary concentrations of BADGEs, parabens, ethyl-protocatechuate, BP-UV filters, TCS and TCC (on a volume basis) ranged 0.3-20.9 (geometric mean: 0.9), 1.6-1010 (24.2), <2-71.0 (2.1), 0.5-1120 (4.4), <0.5-2580 (8.0) and <0.5-1.9 (0.6) ng/mL, respectively. All 19 target chemicals were found in urine, and the highest detection rates were observed for methyl paraben (100%), bisphenol A bis (2,3-dihydroxypropyl) ether (90%), ethyl paraben (87%), 2,4-dihydroxybenzophenone (78%), propyl paraben (72%), and TCS (71%). Estimated daily intakes (EDIurine), calculated on the basis of the measured urinary concentrations, ranged from 0.023 μg/kg bw/day for Σ5BADGEs to 31.4 μg/kg bw/day for Σ6Parabens. PMID:24246946

  11. Water/alcohol soluble electron injection material containing azacrown ether groups: synthesis, characterization and application to enhancement of electroluminescence.

    PubMed

    Wu, Chia-Shing; Lu, Huai-An; Chen, Chiao-Pei; Guo, Tzung-Fang; Chen, Yun

    2014-03-01

    Using an environmentally stable metal as the cathode in a polymer light-emitting diode (PLED) is an essential requirement for its practical application. We present the preparation of a water/alcohol soluble copoly(p-phenylene) (P1) containing pendant azacrown ether and ethylene glycol ether groups as a highly efficient electron injection layer (EIL) for PLEDs, allowing the use of environmentally stable aluminum as the cathode. Multilayer PLEDs [ITO/PEDOT:PSS/PF-Green-B/EIL/Al] using P1 as EIL exhibit significantly enhanced device performance, particularly in the presence of K2CO3 or Cs2CO3. The maximum luminous power efficiency and maximum luminance of the device with Cs2CO3-doped P1 as EIL were enhanced to 9.16 lm W(-1) and 17,050 cd m(-2), respectively, compared with those without EIL (0.16 lm W(-1), 890 cd m(-2)). The turn-on voltage was also significantly reduced from 5.7 V to 3.7 V simultaneously. The performance enhancement has been attributed to improved electron injection which has been confirmed by the rise in open-circuit voltage (Voc) obtained from photovoltaic measurements. The incorporation of such an electron injection layer significantly enhances device performance for PLEDs with an environmentally stable metal as the cathode. PMID:24442208

  12. Expression Levels of the Yeast Alcohol Acetyltransferase Genes ATF1, Lg-ATF1, and ATF2 Control the Formation of a Broad Range of Volatile Esters

    PubMed Central

    Verstrepen, Kevin J.; Van Laere, Stijn D. M.; Vanderhaegen, Bart M. P.; Derdelinckx, Guy; Dufour, Jean-Pierre; Pretorius, Isak S.; Winderickx, Joris; Thevelein, Johan M.; Delvaux, Freddy R.

    2003-01-01

    Volatile aroma-active esters are responsible for the fruity character of fermented alcoholic beverages such as beer and wine. Esters are produced by fermenting yeast cells in an enzyme-catalyzed intracellular reaction. In order to investigate and compare the roles of the known Saccharomyces cerevisiae alcohol acetyltransferases, Atf1p, Atf2p and Lg-Atf1p, in volatile ester production, the respective genes were either deleted or overexpressed in a laboratory strain and a commercial brewing strain. Subsequently, the ester formation of the transformants was monitored by headspace gas chromatography and gas chromatography combined with mass spectroscopy (GC-MS). Analysis of the fermentation products confirmed that the expression levels of ATF1 and ATF2 greatly affect the production of ethyl acetate and isoamyl acetate. GC-MS analysis revealed that Atf1p and Atf2p are also responsible for the formation of a broad range of less volatile esters, such as propyl acetate, isobutyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate, and phenyl ethyl acetate. With respect to the esters analyzed in this study, Atf2p seemed to play only a minor role compared to Atf1p. The atf1Δ atf2Δ double deletion strain did not form any isoamyl acetate, showing that together, Atf1p and Atf2p are responsible for the total cellular isoamyl alcohol acetyltransferase activity. However, the double deletion strain still produced considerable amounts of certain other esters, such as ethyl acetate (50% of the wild-type strain), propyl acetate (50%), and isobutyl acetate (40%), which provides evidence for the existence of additional, as-yet-unknown ester synthases in the yeast proteome. Interestingly, overexpression of different alleles of ATF1 and ATF2 led to different ester production rates, indicating that differences in the aroma profiles of yeast strains may be partially due to mutations in their ATF genes. PMID:12957907

  13. Occurrence of phthalate diesters (phthalates), p-hydroxybenzoic acid esters (parabens), bisphenol A diglycidyl ether (BADGE) and their derivatives in indoor dust from Vietnam: Implications for exposure.

    PubMed

    Tran, Tri Manh; Minh, Tu Binh; Kumosani, Taha A; Kannan, Kurunthachalam

    2016-02-01

    Phthalate diesters (phthalates), esters of p-hydroxybenzoic acid (parabens), and bisphenol A diglycidyl ether (BADGE) are used in personal care products, food packages, household products, or pharmaceuticals. These compounds possess endocrine-disrupting potentials and have been reported to occur in the environment. Nevertheless, no previous studies have reported the occurrence of these compounds in indoor dust from Vietnam. In this study, nine phthalates, six parabens, and four BADGEs were determined in indoor dust samples collected from Hanoi, Hatinh, Hungyen, and Thaibinh, in Vietnam. Total concentrations of phthalates, parabens, and BADGEs in indoor dust ranged from 3440 to 106,000 ng/g (median: 22,600 ng/g), 40-840 ng/g (median: 123 ng/g), and 23 to 1750 ng/g (median: 184 ng/g), respectively. Based on the measured median concentration of phthalates, parabens, and BADGEs in indoor dust, we estimated human exposure doses to these compounds through indoor dust ingestion for various age groups. The exposure doses to phthalates, parabens, and BADGEs decreased with age and ranged from 19.4 to 90.4 ng/kg-bw/d, 0.113-0.528 ng/kg-bw/d, and 0.158-0.736 ng/kg-bw/d, respectively. This is the first study on the occurrence and human exposure of phthalates, parabens, and BADGEs in indoor dust from Vietnam. PMID:26498104

  14. Formation and cleansing performance of bicontinuous microemulsions in water/poly (oxyethylene) alkyl ether/ester-type oil systems.

    PubMed

    Aramaki, Kenji; Tawa, Kosuke; Shrestha, Lok Kumar; Iwanaga, Tetsuro; Kamada, Miho

    2013-01-01

    Phase behaviors in water/poly(oxyethylene) dodecyl ether (C₁₂EO(n), n = 4, 6, 8)/cetyl isooctanoate (CIO) systems were studied. In the C₁₂EO₆ and C₁₂EO₈ systems, self-assembled structures with positive curvatures, such as O/W microemulsions, and micellar cubic and hexagonal phases, were observed. A wider region of a lamellar liquid-crystalline phase, which included a narrow microemulsion region joined by a miscibility gap, was observed in the C₁₂EO₄ system. The structure of the microemulsion phase in the C₁₂EO₄ system was characterized by pulsed-field-gradient NMR (PFG-NMR) and small angle X-ray scattering (SAXS) techniques. PFG-NMR measurements indicated that the structure of the microemulsion was bicontinuous; both water and oil phases were continuous within the microemulsion. Pair-distance distribution function, p (r), and structure factors obtained by Generalized Indirect Fourier Transformation (GIFT) analysis of the SAXS data showed that the microemulsion domain sizes decreased with an increase in the oil content. The structure of the bicontinuous microemulsion was consistent with the results of a detergency test, in which the microemulsion samples were applied to lipstick dirt on an artificial skin plate. Detergency was observed to be better for the microemulsion at lower oil contents because of the larger oil domain size at these low concentrations. PMID:24088518

  15. Saccharomyces kudriavzevii and Saccharomyces uvarum differ from Saccharomyces cerevisiae during the production of aroma-active higher alcohols and acetate esters using their amino acidic precursors.

    PubMed

    Stribny, Jiri; Gamero, Amparo; Pérez-Torrado, Roberto; Querol, Amparo

    2015-07-16

    Higher alcohols and acetate esters are important flavour and aroma components in the food industry. In alcoholic beverages these compounds are produced by yeast during fermentation. Although Saccharomyces cerevisiae is one of the most extensively used species, other species of the Saccharomyces genus have become common in fermentation processes. This study analyses and compares the production of higher alcohols and acetate esters from their amino acidic precursors in three Saccharomyces species: Saccharomyces kudriavzevii, Saccharomyces uvarum and S. cerevisiae. The global volatile compound analysis revealed that S. kudriavzevii produced large amounts of higher alcohols, whereas S. uvarum excelled in the production of acetate esters. Particularly from phenylalanine, S. uvarum produced the largest amounts of 2-phenylethyl acetate, while S. kudriavzevii obtained the greatest 2-phenylethanol formation from this precursor. The present data indicate differences in the amino acid metabolism and subsequent production of flavour-active higher alcohols and acetate esters among the closely related Saccharomyces species. This knowledge will prove useful for developing new enhanced processes in fragrance, flavour, and food industries. PMID:25886016

  16. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Marcolli, C.; Booth, A. M.; Lienhard, D. M.; Soonsin, V.; Krieger, U. K.; Topping, D. O.; McFiggans, G.; Peter, T.; Seinfeld, J. H.

    2011-09-01

    We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl-, Br-, NO3-, HSO4-, and SO42-. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization algorithms. A number of exemplary calculations for systems containing atmospherically relevant aerosol components are shown. Amongst others, we discuss aqueous mixtures of ammonium sulfate with

  17. New and extended parameterization of the thermodynamic model AIOMFAC: calculation of activity coefficients for organic-inorganic mixtures containing carboxyl, hydroxyl, carbonyl, ether, ester, alkenyl, alkyl, and aromatic functional groups

    NASA Astrophysics Data System (ADS)

    Zuend, A.; Marcolli, C.; Booth, A. M.; Lienhard, D. M.; Soonsin, V.; Krieger, U. K.; Topping, D. O.; McFiggans, G.; Peter, T.; Seinfeld, J. H.

    2011-05-01

    We present a new and considerably extended parameterization of the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) at room temperature. AIOMFAC combines a Pitzer-like electrolyte solution model with a UNIFAC-based group-contribution approach and explicitly accounts for interactions between organic functional groups and inorganic ions. Such interactions constitute the salt-effect, may cause liquid-liquid phase separation, and affect the gas-particle partitioning of aerosols. The previous AIOMFAC version was parameterized for alkyl and hydroxyl functional groups of alcohols and polyols. With the goal to describe a wide variety of organic compounds found in atmospheric aerosols, we extend here the parameterization of AIOMFAC to include the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkenyl, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon. Thermodynamic equilibrium data of organic-inorganic systems from the literature are critically assessed and complemented with new measurements to establish a comprehensive database. The database is used to determine simultaneously the AIOMFAC parameters describing interactions of organic functional groups with the ions H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl-, Br-, NO3-, HSO4-, and SO42-. Detailed descriptions of different types of thermodynamic data, such as vapor-liquid, solid-liquid, and liquid-liquid equilibria, and their use for the model parameterization are provided. Issues regarding deficiencies of the database, types and uncertainties of experimental data, and limitations of the model, are discussed. The challenging parameter optimization problem is solved with a novel combination of powerful global minimization algorithms. A number of exemplary calculations for systems containing atmospherically relevant aerosol components are shown. Amongst others, we discuss aqueous mixtures of ammonium sulfate with

  18. 27 CFR 21.108 - Ethyl ether.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Ethyl ether. 21.108 Section 21.108 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.108 Ethyl ether. (a) Odor. Characteristic odor....

  19. 27 CFR 21.108 - Ethyl ether.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Ethyl ether. 21.108 Section 21.108 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.108 Ethyl ether. (a) Odor. Characteristic odor....

  20. Ethyl-tertiary-butyl-ether (ETBE) as an aviation fuel: Eleventh international symposium on alcohol fuels

    SciTech Connect

    Maben, G.D.; Shauck, M.E.; Zanin, M.G.

    1996-12-31

    This paper discusses the preliminary flight testing of an aircraft using neat burning ethyl-tertiary-butyl-ether (ETBE) as a fuel. No additional changes were made to the fuel delivery systems which had previously been modified to provide the higher fuel flow rates required to operate the engine on neat ethanol. Air-fuel ratios were manually adjusted with the mixture control. This system allows the pilot to adjust the mixture to compensate for changes in air density caused by altitude, pressure and temperature. The engine was instrumented to measure exhaust gas temperatures (EGT), cylinder head temperatures (CHT), and fuel flows, while the standard aircraft instruments were used to collect aircraft performance data. Baseline engine data for ETBE and Avgas are compared. Preliminary data indicates the technical and economic feasibility of using ETBE as an aviation fuel for the piston engine fleet. Furthermore, the energy density of ETBE qualifies it as a candidate for a turbine engine fuel of which 16.2 billion gallons are used in the US each year.

  1. The potential for alcohols and related ethers to displace conventional gasoline components

    SciTech Connect

    Hadder, G.R.; McNutt, B.D.

    1996-02-01

    The United States Department of Energy is required by law to determine the feasibility of producing sufficient replacement fuels to replace 30 percent of the projected United States consumption of motor fuels by light duty vehicles in the year 2010. A replacement fuel is a non-petroleum portion of gasoline, including alcohols, natural gas and certain other components. A linear program has been used to study refinery impacts for production of ``low petroleum`` gasolines, which contain replacement fuels. The analysis suggests that high oxygenation is the key to meeting the replacement fuel target, and major contributors to cost increase can include investment in processes to produce olefins for etherification with alcohols. High oxygenation can increase the costs of control of vapor pressure, distillation properties, and pollutant emissions of gasolines. Year-round low petroleum gasoline with near-30 percent non-petroleum might be produced with cost increases of 23 to 37 cents per gallon, with substantial decreases in greenhouse gas emissions in some cases. Cost estimates are sensitive to assumptions about extrapolation of a national model for pollutant emissions, availability of raw materials and other issues. Reduction in crude oil use, a major objective of the low petroleum gasoline program, is 10 to 17 percent in the analysis.

  2. Influence of nitrogen supply on the production of higher alcohols/esters and expression of flavour-related genes in cachaça fermentation.

    PubMed

    Vidal, Esteban Espinosa; de Billerbeck, Gustavo M; Simões, Diogo Ardaillon; Schuler, Alexandre; François, Jean Marie; de Morais, Marcos Antonio

    2013-05-01

    This study provides the first attempt to analyse the influence of ammonium supplements on sugar-cane juice fermentation and the flavour profile in a cachaça industrial process. The objective was to find a relationship between higher alcohol/ester content and the transcription levels of the main genes involved in production of these compounds under cachaça fermentation. Sugar-cane juice with a low amount of assimilable nitrogen (81 mg N/L), was further supplemented with mid-range or high concentrations of ammonium sulfate. Overall, higher alcohol production was reduced by ammonium supplementation, and this can be correlated with a general downregulation of genes encoding decarboxylases and dehydrogenases of the Ehrlich pathway. The production of acetate esters was enhanced by mid-range ammonium supplementation and the production of acyl esters by high ammonium supplementation. The acyl esters could be correlated with expression of alcohol acyl-transferase EEB1 and the acyl esterase IAH1. PMID:23265543

  3. Biodegradable microfluidic scaffolds for tissue engineering from amino alcohol-based poly(ester amide) elastomers

    PubMed Central

    Wang, Jane; Bettinger, Christopher J; Langer, Robert S

    2010-01-01

    Biodegradable polymers with high mechanical strength, flexibility and optical transparency, optimal degradation properties and biocompatibility are critical to the success of tissue engineered devices and drug delivery systems. Most biodegradable polymers suffer from a short half-life due to rapid degradation upon implantation, exceedingly high stiffness, and limited ability to functionalize the surface with chemical moieties. This work describes the fabrication of microfluidic networks from poly(ester amide), poly(1,3-diamino-2-hydroxypropane-co-polyol sebacate) (APS), a recently developed biodegradable elastomeric polymer. Microfluidic scaffolds constructed from APS exhibit a much lower Young's modulus and a significantly longer degradation half-life than those of previously reported systems. The device is fabricated using a modified replica-molding technique, which is rapid, inexpensive, reproducible and scalable, making the approach ideal for both rapid prototyping and manufacturing of tissue engineering scaffolds. PMID:21220957

  4. 27 CFR 21.108 - Ethyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ethyl ether. 21.108 Section 21.108 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.108 Ethyl ether. (a) Odor. Characteristic odor....

  5. 27 CFR 21.108 - Ethyl ether.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Ethyl ether. 21.108 Section 21.108 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.108 Ethyl ether. (a) Odor. Characteristic odor....

  6. Clinical use of meconium fatty acid ethyl esters for identifying children at risk for alcohol-related disabilities: the first reported case.

    PubMed

    Zelner, Irene; Shor, Sarit; Lynn, Hazel; Roukema, Henry; Lum, Lisa; Eisinga, Kirsten; Koren, Gideon

    2012-01-01

    Fatty acid ethyl esters (FAEEs) in meconium are validated biomarkers of heavy fetal alcohol exposure that may potentially be used clinically for identifying children at risk for alcohol-related disabilities. However, until now, FAEEs have been largely used anonymously in epidemiological studies, and by child protection authorities in need for verification of heavy alcohol use in pregnancy. Here we describe the first case of a neonate identified as part of a research study on a pilot neonatal screening program for prenatal alcohol exposure. The neonate's meconium tested high for FAEEs (52 nmol/g; positive cut-off ≥ 2 nmol/g), which prompted active follow-up of the infant's development, identifying early neurocognitive problems and allowing initiation of a remedial program. PMID:22247425

  7. Conversion of a metal-organic framework to N-doped porous carbon incorporating Co and CoO nanoparticles: direct oxidation of alcohols to esters.

    PubMed

    Zhou, Yu-Xiao; Chen, Yu-Zhen; Cao, Lina; Lu, Junling; Jiang, Hai-Long

    2015-05-14

    A Co-based metal-organic framework, ZIF-67, has been exploited as a self-template to afford N-doped porous carbon incorporating Co NPs with surface-oxidized CoO species, which exhibit excellent catalytic activity, selectivity and magnetic recyclability toward the direct oxidation of alcohols to esters with O2 as a benign oxidant under mild conditions. PMID:25877956

  8. A metathesis model for the dehydrogenative coupling of amines with alcohols and esters into carboxamides by Milstein's [Ru(PNN)(CO)(H)] catalysts.

    PubMed

    Hasanayn, Faraj; Harb, Hassan

    2014-08-18

    Milstein's [Ru(PNN)(CO)(H)] catalyst (1-Ru) is known to mediate the dehydrogenative coupling of alcohols into esters. When it is used in alcohol-amine mixtures it catalyzes carboxamide formation selectively over esters and imines. The given chemistry is generally accepted to follow metal-ligand cooperation (MLC) mechanisms involving hemiacetals and hemiaminals as intermediates. Using electronic structure DFT methods we investigate alternative, more direct OR/H and NHR/H metal/acyl metathesis routes to coupling that circumvent the intermediacy of the hemiacetal and the hemiaminal. The newly proposed mechanism involves formation of hemiacetaloxide and hemiaminaloxide ion-pairs by addition of an aldehyde (from metal-catalyzed alcohol dehydrogenation) to an octahedral ruthenium-alkoxide or ruthenium-amide intermediate (from alcohol or amine addition to 1-Ru), followed by simple rearrangement (slippage) within the intact ion-pairs to transfer a hydride from the hemiacetaloxide or hemiaminaloxide to the metal. We show that the computed potential energy surfaces that are sometimes invoked to support the MLC mechanism correspond to indirect routes to metathesis. Both the ion-pair and the MLC routes predict the dehydrogenative coupling of ethanol and methanol into methyl acetate to be kinetically much more favored than the kinetics of formation of N-methylacetamide from ethanol and methylamine. However, the calculations provide evidence for the accessibility of a low energy NHR/OR metathesis path that would amidate the ester into the experimentally observed thermodynamically more favored carboxamide product. In fact, 1-Ru is known to be a catalyst for ester amidation. PMID:25079590

  9. Esters of some non-steroidal anti-inflammatory drugs with cinnamyl alcohol are potent lipoxygenase inhibitors with enhanced anti-inflammatory activity.

    PubMed

    Theodosis-Nobelos, Panagiotis; Kourti, Malamati; Tziona, Paraskevi; Kourounakis, Panos N; Rekka, Eleni A

    2015-11-15

    Novel esters of non steroidal anti-inflammatory drugs, α-lipoic acid and indol-3-acetic acid with cinnamyl alcohol were synthesised by a straightforward method and at high yields (60-98%). They reduced acute inflammation more than the parent acids and are potent inhibitors of soybean lipoxygenase. Selected structures decreased plasma lipidemic indices in Triton-induced hyperlipidemia to rats. Therefore, the synthesised compounds may add to the current knowledge about agents acting against various inflammatory disorders. PMID:26494261

  10. High-effective approach from amino acid esters to chiral amino alcohols over Cu/ZnO/Al2O3 catalyst and its catalytic reaction mechanism.

    PubMed

    Zhang, Shuangshuang; Yu, Jun; Li, Huiying; Mao, Dongsen; Lu, Guanzhong

    2016-01-01

    Developing the high-efficient and green synthetic method for chiral amino alcohols is an intriguing target. We have developed the Mg(2+)-doped Cu/ZnO/Al2O3 catalyst for hydrogenation of L-phenylalanine methyl ester to chiral L-phenylalaninol without racemization. The effect of different L-phenylalanine esters on this title reaction was studied, verifying that Cu/ZnO/Al2O3 is an excellent catalyst for the hydrogenation of amino acid esters to chiral amino alcohols. DFT calculation was used to study the adsorption of substrate on the catalyst, and showed that the substrate adsorbs on the surface active sites mainly by amino group (-NH2) absorbed on Al2O3, and carbonyl (C=O) and alkoxy (RO-) group oxygen absorbed on the boundary of Cu and Al2O3. This catalytic hydrogenation undergoes the formation of a hemiacetal intermediate and the cleavage of the C-O bond (rate-determining step) by reacting with dissociated H to obtain amino aldehyde and methanol ad-species. The former is further hydrogenated to amino alcohols, and the latter desorbs from the catalyst surface. PMID:27619990

  11. Predictive analysis of beer quality by correlating sensory evaluation with higher alcohol and ester production using multivariate statistics methods.

    PubMed

    Dong, Jian-Jun; Li, Qing-Liang; Yin, Hua; Zhong, Cheng; Hao, Jun-Guang; Yang, Pan-Fei; Tian, Yu-Hong; Jia, Shi-Ru

    2014-10-15

    Sensory evaluation is regarded as a necessary procedure to ensure a reproducible quality of beer. Meanwhile, high-throughput analytical methods provide a powerful tool to analyse various flavour compounds, such as higher alcohol and ester. In this study, the relationship between flavour compounds and sensory evaluation was established by non-linear models such as partial least squares (PLS), genetic algorithm back-propagation neural network (GA-BP), support vector machine (SVM). It was shown that SVM with a Radial Basis Function (RBF) had a better performance of prediction accuracy for both calibration set (94.3%) and validation set (96.2%) than other models. Relatively lower prediction abilities were observed for GA-BP (52.1%) and PLS (31.7%). In addition, the kernel function of SVM played an essential role of model training when the prediction accuracy of SVM with polynomial kernel function was 32.9%. As a powerful multivariate statistics method, SVM holds great potential to assess beer quality. PMID:24837965

  12. Combined use of fatty acid ethyl esters and ethyl glucuronide in hair for diagnosis of alcohol abuse: interpretation and advantages.

    PubMed

    Pragst, F; Rothe, M; Moench, B; Hastedt, M; Herre, S; Simmert, D

    2010-03-20

    In this study the combined use of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) for diagnoses of chronically excessive alcohol abuse is investigated at 174 hair samples from driving ability examination, workplace testing and child custody cases for family courts and evaluated with respect to the basics of interpretation. Using the cut-off values of 0.50 ng/mg for FAEE and 25 pg/mg for EtG, both markers were in agreement in 75% of the cases with 103 negative and 28 positive results and there were 30 cases with FAEE positive and EtG negative and 13 cases with FAEE negative and EtG positive. As the theoretical basis of interpretation, the pharmacokinetics of FAEE and EtG is reviewed for all steps between drinking of ethanol to incorporation in hair with particular attention to relationships between alcohol dose and concentrations in hair. It is shown that the concentrations of both markers are essentially determined by the area under the ethanol concentration in blood vs. time curve AUC(EtOH), despite large inter-individual variations. It is demonstrated by calculation of AUC(EtOH) on monthly basis for moderate, risky and heavy drinking that AUC(EtOH) increases very strongly in the range between 60 and 120 g ethanol per day. This specific feature which is caused by the zero-order elimination of ethanol is a favorable prerequisite for a high discrimination power of the hair testing for alcohol abuse. From the consideration of the different profiles of FAEE and EtG along the hair and in agreement with the literature survey, a standardized hair segment 0-3 cm is proposed with cut-off values of 0.5 ng/mg for FAEE and 30 pg/mg for EtG. This improves also the agreement between FAEE and EtG results in the cases of the present study. A scheme for combined interpretation of FAEE and EtG is proposed which uses the levels of abstinence and the double of the cut-off values as criteria in addition to the cut-off's. Considering the large variations in the relationship

  13. Potentialities of two solventless extraction approaches--stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines.

    PubMed

    Perestrelo, R; Nogueira, J M F; Câmara, J S

    2009-12-15

    A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography-quadrupole mass spectrometry (SBSE-LD/LVI-GC-qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min(-1) for the solvent vent flow rate and 10 degrees C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 microm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 degrees C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested, with correlation coefficients higher than 0.984 for HS-SPME and 0.982 for SBES-LD approach, for all analytes. A good reproducibility was attained and low detection limits were achieved using both SBSE-LD (0.03-28.96 microg L(-1)) and HS-SPME (0.02-20.29 microg L(-1)) methodologies. The quantification limits for SBSE-LD approach ranging from 0.11 to 96.56 microg L(-)and from 0.06 to 67.63 microg L(-1) for HS-SPME. Using the HS-SPME approach an average recovery of about 70% was obtained whilst by using SBSE-LD obtained average recovery were close to 80%. The

  14. QSPR models based on molecular mechanics and quantum chemical calculations. 1. Construction of Boltzmann-averaged descriptors for alkanes, alcohols, diols, ethers and cyclic compounds.

    PubMed

    Dyekjaer, Jane; Rasmussen, Kjeld; Jónsdóttir, Svava

    2002-09-01

    Values for nine descriptors for QSPR (quantitative structure-property relationships) modeling of physical properties of 96 alkanes, alcohols, ethers, diols, triols and cyclic alkanes and alcohols in conjunction with the program Codessa are presented. The descriptors are Boltzmann-averaged by selection of the most relevant conformers out of a set of possible molecular conformers generated by a systematic scheme presented in this paper. Six of these descriptors are calculated with molecular mechanics and three with quantum chemical methods. Especially interesting descriptors are the relative van der Waals energies and the molecular polarizabilities, which correlate very well with boiling points. Five more simple descriptors that only depend on the molecular constitutional formula are also discussed briefly. PMID:12415333

  15. Molecular structures of tert-butyl alcohol and tert-butyl methyl ether as studied by gas electron diffraction combined with vibrational spectroscopy

    NASA Astrophysics Data System (ADS)

    Suwa, Atsuhiko; Ohta, Hiroshi; Konaka, Shigehiro

    1988-02-01

    The molecular of tert-butyl alcohol (TBA) and tert-butyl methyl ether (TBME) have been determined by gas electron diffraction. Vibrational spectra have been measured for TBME. Normal coordinate analyses have been performed to obtain harmonic force fields and to calculate mean amplitudes and shrinkage corrections. Principal bond lengths ( rg) and angles ( rα are: r(OH) = 1.016(14) Å, r(CO) = 1.446(4) Å, r(CC) - 1.529(2) Å, ∠COH = 108(3)° and ∠CCC = 110.9(2)° for TBA r(C 2O) = 1.448(4) Å, r(CC) = 1.532(2) Å, ∠COC = 118.9(14)° and ∠CCC = 111.1(2)° for TBME. The results have been compared with values from molecular mechanics and SCF MO calculations. The observed geometry for TBA is consistent with the rotational constant reported by Valenzuela. The rg(CO) value of TBA is about 0.02 Å larger than that of methanol. The values of rg(C 2O) and ∠COC of TBME are about 0.03 Å and 7° larger than the corresponding values of dimethyl ether and ethyl methyl ether.

  16. Fatty acid ethyl ester concentrations in hair and self-reported alcohol consumption in 644 cases from different origin.

    PubMed

    Süsse, Silke; Selavka, Carl M; Mieczkowski, Tom; Pragst, Fritz

    2010-03-20

    For diagnosis of chronic alcohol abuse, fatty acid ethyl esters (FAEE) were determined in hair samples from 644 individuals, mainly parents from child protection cases. The analysis for ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate was performed according to a validated procedure consisting of external degreasing by two times washing with n-heptane, extraction with a mixture of dimethylsulfoxide and n-heptane, separation and evaporation of the n-heptane layer, headspace solid phase microextraction of the residue after addition of phosphate buffer pH 7.6 and gas chromatography-mass spectrometry using deuterated internal standards. For interpretation, the sum of the concentrations of the four esters C(FAEE) was used with the cut-off's 0.5 ng/mg for the proximal scalp hair segment 0-3 cm or less and 1.0 ng/mg for scalp hair samples with a length between 3 and 6 cm and for body hair. C(FAEE) ranged from 0.11 to 31 ng/mg (mean 1.77 ng/mg, median 0.82 ng/mg). The mean concentration ratio between the 4 esters was 8:45:38:9. 298 cases had C(FAEE) above the cut-off's. Self-reported drinking data were obtained in 553 of the cases in the categories abstinent (156 cases), moderate drinking (252 cases) and excessive drinking (145 cases). Median and box-plot data clearly demonstrate differentiation of these ingestor sub-populations by C(FAEE). However, in the abstinent and moderate groups the consumption was frequently underreported (37 and 110 cases positive) whereas in the group self-reported excessive drinking 32 cases were negative. Comparison of C(FAEE) with carbohydrate-deficient transferrin (CDT) in 139 cases and gamma-glutamyltransferase (GGT) in 136 cases showed a good agreement in CDT- and GGT positive cases (27/28 and 32/41) but a large portion of the negative CDT- and GGT-results with positive hair test (44/100 and 48/95) which is explained mainly by the much shorter time window of CDT and GGT. No significant correlation was found between persons

  17. 27 CFR 21.108 - Ethyl ether.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Ethyl ether. 21.108 Section 21.108 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT....108 Ethyl ether. (a) Odor. Characteristic odor. (b) Specific gravity at 15.56 °/15.56 °C. Not...

  18. Propenyl ether monomers for photopolymerization

    DOEpatents

    Crivello, J.V.

    1996-10-22

    Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of the above formula together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  19. Propenyl ether monomers for photopolymerization

    DOEpatents

    Crivello, James V.

    1996-01-01

    Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  20. Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls.

    PubMed

    Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D; Krische, Michael J

    2015-10-14

    The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo-, and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k, and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k, and 6m, respectively. Primary alcohols 2a, 2l, and 2p were converted to the siloxy-crotylation products 3a, 3l, and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l, and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes. PMID:26418572

  1. Oxazolidines. 2. Synthesis of 2-methyloxazolidines by cyclization of vinyl ethers of 1,2-amino alcohols

    SciTech Connect

    Kukharev, B.F.; Stankevich, V.K.; Klimenko, G.R.; Terent'eva, V.P.; Kukhareva, V.A.

    1986-10-01

    A study has been made of the catalytic activity of a number of proton acids and Lewis acids, amongst which mercury salts were particularly active, in the cyclization of N-phenylethanolamine vinyl ether to 2-methyl-3-phenyloxazolidine. A method for the preparative synthesis of 2-methyloxazolidines has been developed.

  2. Analysis of ethereal extracts of wines and other alcoholic beverages by high-performance liquid chromatography with microbore columns.

    PubMed

    Cartoni, G P; Coccioli, F; Spagnoli, M

    1997-10-10

    The ethereal extracts of wines, beer and vermouth were analysed by high-performance liquid chromatography. The following three characteristic peaks were first identified using GC-MS and then quantitatively determined: 5-hydroxy-methyl-2-furaldehyde, 2-(4-hydroxyphenyl)ethanol and 3-(2-hydroxyethyl)indole. PMID:9440923

  3. Reduction of ferulate ether cross links in maize stover due to selection for low ferulate ester concentrations in seedlings improves cell wall digestibility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We hypothesized that ferulate-mediated cross links between lignin and hemicellulose in the cell walls of grasses could be reduced by inhibition of ferulate ester biosynthesis. Further, a reduction in cross linking should lead to improved digestibility of cell wall polysaccharides. We report here tha...

  4. Catalytic reaction of pi-allyl complexes of palladium with allyl O and N nucleophiles, a new promising route for synthesis of C/sub 16/ amines and ethers

    SciTech Connect

    Fakhretdinov, R.N.; Telin, A.G.; Dzhemilev, U.M.

    1986-06-20

    To develop efficient and promising methods for synthesis of scarce higher unsaturated amines and ethers, they investigated the reaction of tertiary 2,7-octadienylamines, butenyl amines of different structures, and 2,7-octadienyl ethers of aliphatic alcohols and esters of carboxylic acids with butadiene in the presence of Pd catalysts activated by electron-donor and electron-acceptor ligands. A new one-step method was developed for synthesis of polyunsaturated C/sub 16/ amines, ethers, and hydrocarbons with readily available reagents.

  5. Ethers and esters derived from apocynin avoid the interaction between p47phox and p22phox subunits of NADPH oxidase: evaluation in vitro and in silico

    PubMed Central

    Macías-Pérez, Martha Edith; Martínez-Ramos, Federico; Padilla-Martínez, Itzia Irene; Correa-Basurto, José; Kispert, Lowell; Mendieta-Wejebe, Jessica Elena; Rosales-Hernández, Martha Cecilia

    2013-01-01

    NOX (NADPH oxidase) plays an important role during several pathologies because it produces the superoxide anion (O2•−), which reacts with NO (nitric oxide), diminishing its vasodilator effect. Although different isoforms of NOX are expressed in ECs (endothelial cells) of blood vessels, the NOX2 isoform has been considered the principal therapeutic target for vascular diseases because it can be up-regulated by inhibiting the interaction between its p47phox (cytosolic protein) and p22phox (transmembrane protein) subunits. In this research, two ethers, 4-(4-acetyl-2-methoxy-phenoxy)-acetic acid (1) and 4-(4-acetyl-2-methoxy-phenoxy)-butyric acid (2) and two esters, pentanedioic acid mono-(4-acetyl-2-methoxy-phenyl) ester (3) and heptanedioic acid mono-(4-acetyl-2-methoxy-phenyl) ester (4), which are apocynin derivatives were designed, synthesized and evaluated as NOX inhibitors by quantifying O2•− production using EPR (electron paramagnetic resonance) measurements. In addition, the antioxidant activity of apocynin and its derivatives were determined. A docking study was used to identify the interactions between the NOX2′s p47phox subunit and apocynin or its derivatives. The results showed that all of the compounds exhibit inhibitory activity on NOX, being 4 the best derivative. However, neither apocynin nor its derivatives were free radical scavengers. On the other hand, the in silico studies demonstrated that the apocynin and its derivatives were recognized by the polybasic SH3A and SH3B domains, which are regions of p47phox that interact with p22phox. Therefore this experimental and theoretical study suggests that compound 4 could prevent the formation of the complex between p47phox and p22phox without needing to be activated by MPO (myeloperoxidase), this being an advantage over apocynin. PMID:23802190

  6. Fatty acid ethyl esters in hair as alcohol markers: estimating a reliable cut-off point by evaluation of 1,057 autopsy cases.

    PubMed

    Hastedt, Martin; Bossers, Lydia; Krumbiegel, Franziska; Herre, Sieglinde; Hartwig, Sven

    2013-06-01

    Alcohol abuse is a widespread problem, especially in Western countries. Therefore, it is important to have markers of alcohol consumption with validated cut-off points. For many years research has focused on analysis of hair for alcohol markers, but data on the performance and reliability of cut-off values are still lacking. Evaluating 1,057 cases from 2005 to 2011, included a large sample group for the estimation of an applicable cut-off value when compared to earlier studies on fatty acid ethyl esters (FAEEs) in hair. The FAEEs concentrations in hair, police investigation reports, medical history, and the macroscopic and microscopic alcohol-typical results from autopsy, such as liver, pancreas, and cardiac findings, were taken into account in this study. In 80.2 % of all 1,057 cases pathologic findings that may be related to alcohol abuse were reported. The cases were divided into social drinkers (n = 168), alcohol abusers (n = 502), and cases without information on alcohol use. The median FAEEs concentration in the group of social drinkers was 0.302 ng/mg (range 0.008-14.3 ng/mg). In the group of alcohol abusers a median of 1.346 ng/mg (range 0.010-83.7 ng/mg) was found. Before June 2009 the hair FAEEs test was routinely applied to a proximal hair segment of 0-6 cm, changing to a routinely investigated hair length of 3 cm after 2009, as proposed by the Society of Hair Testing (SoHT). The method showed significant differences between the groups of social drinkers and alcoholics, leading to an improvement in the postmortem detection of alcohol abuse. Nevertheless, the performance of the method was rather poor, with an area under the curve calculated from receiver operating characteristic (ROC curve AUC) of 0.745. The optimum cut-off value for differentiation between social and chronic excessive drinking calculated for hair FAEEs was 1.08 ng/mg, with a sensitivity of 56 % and a specificity of 80 %. In relation to the "Consensus on Alcohol Markers 2012

  7. Alcohol

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Alcohol KidsHealth > For Teens > Alcohol Print A A A ... you can make an educated choice. What Is Alcohol? Alcohol is created when grains, fruits, or vegetables ...

  8. Extension of the LOPLS-AA Force Field for Alcohols, Esters, and Monoolein Bilayers and its Validation by Neutron Scattering Experiments.

    PubMed

    Pluhackova, Kristyna; Morhenn, Humphrey; Lautner, Lisa; Lohstroh, Wiebke; Nemkovski, Kirill S; Unruh, Tobias; Böckmann, Rainer A

    2015-12-10

    The recently presented LOPLS-AA all-atom force field for long hydrocarbon chains, based on the OPLS-AA force field, was extended to alcohols, esters, and glyceryl monooleate (GMO) lipids as a model lipid. Dihedral angles were fitted against high level ab initio calculations, and ester charges were increased to improve their hydration properties. Additionally, the ester Lennard-Jones parameters were readjusted to reproduce experimental liquid bulk properties, densities, and heats of vaporization. This extension enabled the setup of LOPLS-AA parameters for GMO molecules. The properties of the lipid force field were tested for the liquid-crystalline phase of a GMO bilayer. The obtained area per lipid for GMO is in good agreement with experiment. Additionally, the lipid dynamics on the subpicosecond to the nanosecond time scale is in excellent agreement with results from time-of-flight (TOF) quasielastic neutron scattering (QENS) experiments on a multilamellar monoolein system, enabling here for the first time the critical evaluation of the short-time dynamics obtained from a molecular dynamics simulation of a membrane system. PMID:26537654

  9. Glycol Ethers As Groundwater Contaminants

    NASA Astrophysics Data System (ADS)

    Ross, Benjamin; Johannson, Gunnar; Foster, Gregory D.; Eckel, William P.

    1992-01-01

    Ether derivatives of dihydroxy alcohols, which are formed from ethylene or propylene, comprise an important group of groundwater contaminants known as glycol ethers. Compounds in this group are used as solvents, cleaning agents, and emulsifiers in many chemical products and manufacturing operations. Glycol ethers have been associated with a variety of toxic effects, and some compounds in the group are relatively potent teratogens. The limited information available suggests that glycol ethers are contaminants in groundwater, especially in anaerobic plumes emanating from disposal of mixed industrial and household waste. Most methods used to analyze groundwater samples cannot adequately detect μg/? (ppb) concentrations of glycol ethers, and the existing methods perform worst for the most widely used and toxic species. A new method capable of analyzing μg/? concentrations of glycol ethers was recently developed, and its use is recommended for groundwater samples where glycol ethers are likely to be present.

  10. Methyl allyl ether formation in plants: novel S-adenosyl L-methionine:coniferyl alcohol 9-O-methyltransferase from suspension cultures of three Linum species.

    PubMed

    Berim, Anna; Schneider, Bernd; Petersen, Maike

    2007-06-01

    A novel 41 kDa methyltransferase displaying high regiospecificity towards the allylic hydroxyl moiety of coniferyl alcohol was cloned from suspension cultures of Linum nodiflorum L. and expressed in E. coli. The apparent K (m) for coniferyl alcohol is 7.23 microM with a V (max) of 707.5 pkat mg(-1) protein at 30 degrees C, whereas the K (m) for the co-substrate S-adenosyl-L-methionine is 18.5 microM. Structure-function relationship studies revealed stringent structure requirements. Even minor substructure deviations as the side-chain saturation or changes in the phenyl ring substitution result in activities decreased by 75-90%. Crotyl and allyl alcohols are not substrates, confirming that the aromatic ring itself is indispensable, and solely the derivatives with a C(3) side-chain are accepted. The enzyme shares only similarities under 46% on amino acid level with other known methyltransferases. The designated reaction product, coniferyl alcohol 9-methyl ether, could be detected in suspension cells. The highest content of up to 0.02% of the dry mass is concurrent with an increase of the specific enzyme activity that reaches its maximum of 3.94 pkat mg(-1) on day 6 of the culture period. Transcript levels estimated by semi-quantitative RT-PCR remain constant until day 6 and recede thereafter. The corresponding methyltransferase from Linum flavum L. differs mainly by one short variable fragment. Biochemical characterization revealed a higher catalytic efficiency and a slightly broader substrate plasticity together with a lower sensitivity to the presence of Zn(2+), Cu(2+) and Co(2+). This is to our knowledge the first report of a regiospecific allylic O-methylation of phenylpropanoids in plants. PMID:17333502

  11. Linear Versus Non-Linear Dose-Response Relationship Between Prenatal Alcohol Exposure and Meconium Concentration of Nine Different Fatty Acid Ethyl Esters.

    PubMed

    Yang, J Y; Kwak, H S; Han, J Y; Choi, J S; Ahn, H K; Oh, Y J; Velázquez-Armenta, E Y; Nava-Ocampo, A A

    2015-01-01

    Presence of individual fatty acid ethyl esters (FAEEs) in meconium is considered to be a reliable biomarker of prenatal alcohol exposure, and their concentration has been found to be linearly associated with poor postnatal development, supporting the widely extended idea that ethanol is a non-threshold teratogen. However, a growing number of epidemiological studies have consistently found a lack of adverse short- and long-term fetal outcomes at low exposure levels. We therefore aimed to investigate the relationship between the concentration of individual FAEEs and prenatal alcohol exposure in meconium samples collected within the first 6 to 12?h after birth from 182 babies born to abstainer mothers and from 54 babies born to women who self-reported either light or moderate alcohol ingestion in the second or third trimester of pregnancy. In most cases, the individual FAEE concentrations were negligible and not significantly different (P >0.05) between exposed and control babies. The concentrations appeared to increase linearly with the dose only in the few babies born to mothers who reported >3 drinks/week. These results provide evidence that the correlation between prenatal alcohol exposure and individual FAEE concentrations in meconium is non-linear shape, with a threshold probably at 3 drinks/week. PMID:26691866

  12. Interstellar Alcohols and the Chemistry of Hot Cores

    NASA Astrophysics Data System (ADS)

    Kress, M. E.; Charnley, S. B.; Tielens, A. G. G. M.; Millar, T. J.

    1994-12-01

    Gas-phase methanol and ethanol have been observed in hot cores, the warm remnants of a molecular cloud in which massive star formation has recently occurred. The newborn stars heat the surrounding gas and dust, evaporating ice mantles containing alcohols which can then participate in gas-phase reactions. Model calculations show that methanol, ethanol, propanol, and butanol drive a chemistry which can form several esters and ethers; our models show that methyl ethyl ether and diethyl ether should form in detectable quantities in cores rich in methanol and ethanol. These reactions can also explain the low observed abundance of gas-phase ethanol in some hot core sources. Possible grain surface mechanisms for the formation of these alcohols will also be presented. We acknowledge support via a DOE fellowship (MEK), a NAS/NRC research associateship at NASA Ames (SBC), a SERC grant to the UMIST Astrophysics Group (TJM), and a grant from NASA's Astrophysics Theory Program (AGGMT).

  13. 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid ethyl ester (THC-COOEt): unsuccessful search for a marker of combined cannabis and alcohol consumption.

    PubMed

    Nadulski, Thomas; Bleeck, Simona; Schräder, Johannes; Bork, Wolf-Rainer; Pragst, Fritz

    2010-03-20

    11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid ethyl ester (THC-COOEt) can be presumed to be a mixed metabolite formed during combined consumption of cannabinoids and alcohol. In order to examine this hypothesis, THC-COOEt and its deuterated analogue D(3)-THC-COOEt were synthesized as reference substance and internal standard from the corresponding carboxylic acids and diazoethane and methods were developed for the sensitive detection of THC-COOEt in plasma and hair based on gas chromatography-electron impact mass spectrometry after silylation with N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS) as well as tandem mass spectrometry (GC-NCI-MS-MS) after derivatization with pentafluoropropionyl anhydride. The methods were applied for THC-COOEt determination to plasma samples from 22 drunk driving cases which contained both ethanol (0.30-2.16 mg/g) and THC-COOH (15-252 ng/mL) as well as to 12 hair samples from drug fatalities which were both positive for THC (0.09-2.04 ng/mg) and fatty acid ethyl esters as markers of chronic alcohol abuse (0.70-6.3 ng/mg). In none of these samples THC-COOEt could be found with limits of detection of 0.3 ng/mL in plasma and 2 pg/mg in hair in 11 samples using GC-NCI-MS and 0.2 pg/mg in one sample using GC-NCI-MS. Therefore, the use of this compound as a marker for combined cannabis and alcohol consumption could not be achieved. PMID:20074877

  14. The application of formyl group activation of bromopyrrole esters to formal syntheses of lycogarubin C, permethyl storniamide A and lamellarin G trimethyl ether

    PubMed Central

    Gupton, John T.; Telang, Nakul; Patteson, Jon; Lescalleet, Kristin; Yeudall, Scott; Sobieski, John; Harrison, Andrew; Curry, Will

    2014-01-01

    Lycogarubin C, permethyl storniamide A and lamellarin G trimethyl ether are pyrrole containing, natural products, which exhibit interesting biological properties. Such properties include anti-tumor activity on a variety of cancer cell lines including those that confer drug resistance, inhibition of HIV integrase and vascular disrupting activity. We now describe the use of methyl and ethyl 3-bromo-2-formylpyrrole-5-carboxylate as building blocks for the formal synthesis of these three highly functionalized, bioactive pyrroles. These new building blocks will now provide ready access to the natural products and many novel analogs due to the ability to easily modify positions 2,3,4 and 5 of the pyrrole core. PMID:25584014

  15. Quantification of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in meconium for detection of alcohol abuse during pregnancy: Correlation study between both biomarkers.

    PubMed

    Cabarcos, Pamela; Tabernero, María Jesús; Otero, José Luís; Míguez, Martha; Bermejo, Ana María; Martello, Simona; De Giovanni, Nadia; Chiarotti, Marcello

    2014-11-01

    This article presents results from 47 meconium samples, which were analyzed for fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) for detection of gestational alcohol consumption. A validated microwave assisted extraction (MAE) method in combination with GC-MS developed in the Institute of Forensic Science (Santiago de Compostela) was used for FAEE and the cumulative concentration of ethyl myristate, ethyl palmitate and ethyl stearate with a cut-off of 600ng/g was applied for interpretation. A simple method for identification and quantification of EtG has been evaluated by ultrasonication followed solid phase extraction (SPE). Successful validation parameters were obtained for both biochemical markers of alcohol intake. FAEE and EtG concentrations in meconium ranged between values lower than LOD and 32,892ng/g or 218ng/g respectively. We have analyzed FAEE and EtG in the same meconium aliquot, enabling comparison of the efficiency of gestational ethanol exposure detection. Certain agreement between the two biomarkers was found as they are both a very specific alcohol markers, making it a useful analysis for confirmation. PMID:25137651

  16. Alcohol

    MedlinePlus

    ... Text Size: A A A Listen En Español Alcohol Wondering if alcohol is off limits with diabetes? Most people with diabetes can have a moderate amount of alcohol. Research has shown that there can be some ...

  17. Alcohol

    MedlinePlus

    If you are like many Americans, you drink alcohol at least occasionally. For many people, moderate drinking ... risky. Heavy drinking can lead to alcoholism and alcohol abuse, as well as injuries, liver disease, heart ...

  18. Magnetic Relaxation Switch Detecting Boric Acid or Borate Ester through One-Pot Synthesized Poly(vinyl alcohol) Functionalized Nanomagnetic Iron Oxide.

    PubMed

    Zhang, Guilong; Lu, Shiyao; Qian, Junchao; Zhong, Kai; Yao, Jianming; Cai, Dongqing; Cheng, Zhiliang; Wu, Zhengyan

    2015-08-01

    We developed a highly efficient magnetic relaxation switch (MRS) system based on poly(vinyl alcohol) functionalized nanomagnetic iron oxide (PVA@NMIO) particles for the detection of boric acid or borate ester (BA/BE). It was found that the addition of BA/BE induced the aggregation of PVA@NMIO particles, resulting in a measurable change in the T2 relaxation time in magnetic resonance measurements. The main mechanism was proposed that the electron-deficient boron atoms of BA/BE caused the aggregation of PVA@NMIO particles through covalent binding to the hydroxyl groups of PVA. This novel detection system displayed excellent selectivity, high sensitivity, and rapid detection for BA/BE. Thus, this system may provide a great application prospect for detection of BA/BE. PMID:26171794

  19. Terpolymers of ethyl acrylate/methacrylic acid/unsaturated acid ester of alcohols and acids as anti-settling agents in coal water slurries

    SciTech Connect

    Savoly, A.; Villa, J.L.; Grinstein, R.H.; Nachfolger, S.J.

    1988-05-17

    This patent describes a pumpable stabilized coal water slurry, having a coal content of at least about 50% by weight wherein at least 80% of the coal particles are about 200 mesh or finer, containing from about 0.01% to about 1% by weight of the slurry of a water soluble terpolymer of ethylacrylate (A), metacrylic acid (B) and a third monomer (C) selected from the group consisting of an unsaturated carboxylic acid ester of an alcohol and an ethoxylated carboxylic acid. The unsaturated carboxylic acid is a mono- or di- basic unsaturated carboxylic acid of 3 to 10 carbon atoms selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid.

  20. Short-range order and fractal cluster structure of aggregates of barium titanate microparticles in a composite based on cyano-ethyl ester of polyvinyl alcohol

    NASA Astrophysics Data System (ADS)

    Krasovskii, A. N.; Novikov, D. V.; Vasina, E. S.; Matveichikova, P. V.; Sychev, M. M.; Rozhkova, N. N.

    2015-12-01

    The distribution of barium titanate (BaTiO3) microparticles in the matrix of cyano-ethyl ester of polyvinyl alcohol and the change in the surface energy upon introduction of shungite carbon nanoclusters into the dielectric composite have been investigated using the methods of scanning electron microscopy and contact angles. The computer processing of the electron microscopy data has demonstrated that the introduction of 0.04% shungite carbon nanoparticles into the composite leads to a decrease in the spatial homogeneity of the quasi-lattice and to an increase in the local density distribution of BaTiO3 microparticles, as well as in the correlation length corresponding to the formation of an infinite cluster of BaTiO3 particles. It has been found that, in this case, the surface energy and dielectric permittivity of the composite extremely increase.

  1. Role of single-walled carbon nanotubes on ester hydrolysis and topography of electrospun bovine serum albumin/poly(vinyl alcohol) membranes.

    PubMed

    Ford, Ericka N J; Suthiwangcharoen, Nisaraporn; D'Angelo, Paola A; Nagarajan, Ramanathan

    2014-07-23

    Electrospun membranes were studied for the chemical deactivation of threat agents by means of enzymatic proteins. Protein loading and the surface chemistry of hybrid nanofibers influenced the efficacy by which embedded enzymes could digest the substrate of interest. Bovine serum albumin (BSA), selected as a model protein, was electrospun into biologically active fibers of poly(vinyl alcohol), PVA. Single-walled carbon nanotubes (SWNTs) were blended within these mixtures to promote protein assembly during the process of electrospinning and subsequently the ester hydrolysis of the substrates. The SWNT incorporation was shown to influence the topography of PVA/BSA nanofibers and enzymatic activity against paraoxon, a simulant for organophosphate agents and a phosphorus analogue of p-nitrophenyl acetate (PNA). The esterase activity of BSA against PNA was uncompromised upon its inclusion within nanofibrous membranes because similar amounts of PNA were hydrolyzed by BSA in solution and the electrospun BSA. However, the availability of BSA along the fiber surface was shown to affect the ester hydrolysis of paraoxon. Atomic force microscopy images of nanofibers implicated the surface migration of BSA during the electrospinning of SWNT filled dispersions, especially as greater weight fractions of protein were added to the spinning mixtures. In turn, the PVA/SWNT/BSA nanofibers outperformed the nanotube free PVA/BSA membranes in terms of paraoxon digestion. The results support the development of electrospun polymer nanofiber platforms, modulated by SWNTs for enzyme catalytic applications relevant to soldier protective ensembles. PMID:25007411

  2. Bacterial degradation of glycol ethers.

    PubMed

    Kawai, F

    1995-12-01

    Assimilation of ethyleneglycol (EG) ethers by polyethyleneglycol-utilizing bacteria was examined. Ethyleneglycol ether-utilizing bacteria were also isolated from soil and activated sludge samples by enrichment-culture techniques. Three strains (4-5-3, EC 1-2-1 and MC 2-2-1) were selected and characterized as Pseudomonas sp. 4-5-3, Xanthobacter autotrophicus, and an unidentified gram-negative, non-spore-forming rod respectively. Their growth characteristics were examined: Pseudomonas sp. 4-5-3 assimilated EG (diethyleneglycol, DEG) monomethyl, monoethyl and monobutyl ethers, DEG, propanol and butanol. X. autotrophicus EC 1-2-1 grew well on EG monoethyl and monobutyl ethers, EG and primary alcohols (C1-C4), and slightly on EG monomethyl ether. The strain MC 2-2-1 grew on EG monomethyl ether, EG, primary alcohols (C1-C4), and 1,2-propyleneglycol (PG). The mixed culture of Pseudomonas sp. 4-5-3 and X. autotrophicus EC 1-2-1 showed better growth and improved degradation than respective single cultures towards EG monomethyl, monoethyl or monobutyl ethers. Intact cells of Pseudomonas sp. 4-5-3 degraded various kinds of monoalkyl ethers, which cannot be assimilated by the strain. Metabolic products were characterized from reaction supernatants of intact cells of Pseudomonas sp. 4-5-3 with EG or DEG monoethyl ethers: they were analyzed by thin-layer chromatography and GC-MS and found to be ethoxyacetic acid and ethoxyglycoxyacetic acid. Also, PG monoalkyl ethers (C1-C4), dipropyleneglycol monoethyl and monomethyl ethers and tripropyleneglycol monomethyl ether were assimilated by polypropyleneglycol-utilizing Corynebacterium sp. 7. PMID:8597556

  3. High Yield of Wax Ester Synthesized from Cetyl Alcohol and Octanoic Acid by Lipozyme RMIM and Novozym 435

    PubMed Central

    Kuo, Chia-Hung; Chen, Hsin-Hung; Chen, Jiann-Hwa; Liu, Yung-Chuan; Shieh, Chwen-Jen

    2012-01-01

    Wax esters are long-chain esters that have been widely applied in premium lubricants, parting agents, antifoaming agents and cosmetics. In this study, the biocatalytic preparation of a specific wax ester, cetyl octanoate, is performed in n-hexane using two commercial immobilized lipases, i.e., Lipozyme® RMIM (Rhizomucor miehei) and Novozym® 435 (Candida antarctica). Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) are employed to evaluate the effects of reaction time (1–5 h), reaction temperature (45–65 °C), substrate molar ratio (1–3:1), and enzyme amount (10%–50%) on the yield of cetyl octanoate. Using RSM to optimize the reaction, the maximum yields reached 94% and 98% using Lipozyme® RMIM and Novozym® 435, respectively. The optimum conditions for synthesis of cetyl octanoate by both lipases are established and compared. Novozym® 435 proves to be a more efficient biocatalyst than Lipozyme® RMIM. PMID:23109878

  4. Alcohol

    MedlinePlus

    ... Got Homework? Here's Help White House Lunch Recipes Alcohol KidsHealth > For Kids > Alcohol Print A A A Text Size What's in ... What Is Alcoholism? Say No en español El alcohol Getting the Right Message "Hey, who wants a ...

  5. Enzymatic Synthesis of Furfuryl Alcohol Ester with Oleic Acid by Candida antarctica Lipase B and Its Kinetic Study

    NASA Astrophysics Data System (ADS)

    Sengupta, Avery; Dey, Tanmoy; Ghosh, Mahua; Ghosh, Jaydip; Ghosh, Santinath

    2012-08-01

    This study investigated the successful enzymatic production of furfuryl oleate and its detailed kinetic study by Michaelis-Menten model. Esterification of oleic acid and furfuryl alcohol by Candida antarctica lipase B (Novozym 435 preparation) in a solvent free system was studied in the present work at 1:1 molar ratio of furfuryl alcohol and oleic acid. About 99 % conversion (on the basis of oleic acid) has been achieved within 6 h at 5 % enzyme concentration. Ping-pong bi-bi mechanism (inhibition phenomenon taken into account) was applied to describe the ratios as a complex kinetic model. The kinetic parameters were determined using MATLAB language programme. The two initial rate constants KA and KB respectively were found out by different progress curves plotted with the help of MATLAB language programme. It was concluded from the results that furfuryl alcohol considerably inhibited the enzymatic reaction while oleic acid had negligible inhibitory effect. It was clearly seen that the initial rate was increased with the increase in the furfuryl alcohol concentration until 2 M/L after which there was a drop in the initial rate depicting the inhibitory effect of furfuryl alcohol. Surprisingly, it has been observed that addition of 0.1 mol of product activated the esterification reaction. Finally, the model was found to be statistically fitting well with the experimental data.

  6. Inorganic-organic polymer electrolytes based on poly(vinyl alcohol) and borane/poly(ethylene glycol) monomethyl ether for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Aydın, Hamide; Şenel, Mehmet; Erdemi, Hamit; Baykal, Abdülhadi; Tülü, Metin; Ata, Ali; Bozkurt, Ayhan

    In this study, poly(vinyl alcohol) (PVA) was modified with poly(ethylene glycol) monomethyl ether (PEGME) using borane-tetrahydrofuran (BH 3/THF) complex. Molecular weights of both PVA and PEGME were varied prior to reaction. Boron containing comb-branched copolymers were produced and abbreviated as PVA1PEGMEX and PVA2PEGMEX. Then polymer electrolytes were successfully prepared by doping of the host matrix with CF 3SO 3Li at several stoichiomeric ratios with respect to EO to Li. The materials were characterized via nuclear magnetic resonance (1H NMR and 11B NMR), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG) and differential scanning calorimeter (DSC). The ionic conductivity of these novel polymer electrolytes were studied by dielectric-impedance spectroscopy. Li-ion conductivity of these polymer electrolytes depends on the length of the side units as well as the doping ratio. Such electrolytes possess satisfactory ambient temperature ionic conductivity (>10 -4 S cm -1). Cyclic voltammetry results illustrated that the electrochemical stability domain extends over 4 V.

  7. Combined toxicities of methyl tert-butyl ether and its metabolite tert-butyl alcohol on earthworms via different exposure routes.

    PubMed

    Lee, Woo-Mi; Yoon, Youngdae; An, Youn-Joo

    2015-06-01

    Methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) are among the major soil contaminants that threaten the health of soil ecosystems. Many MTBE-contaminated sites accumulate TBA, because TBA is the intermediate of MTBE biodegradation. To access the risk of MTBE and TBA in soil, we investigated the combined toxicities of MTBE and TBA using two earthworm species, Perionyx excavatus and Eisenia andrei, as well as the toxic effects via different exposure routes. The combined toxicity showed weak antagonistic effects (LC50mix values were slightly greater than 1.0), and sensitivity toward same pollutants differed in the two earthworm species. Moreover, the toxicity of MTBE and TBA was also affected by the exposure route; both filter paper and artificial soil tests showed that dermal-only exposure to MTBE had an even greater toxic effect than combined dermal and oral exposure. Thus, we suggest that diverse environmental factors including organic materials, the physicochemical properties of the contact media, and the exposure routes of the organism, should be taken into consideration when assessing the effects of pollutants on organisms in diverse environmental systems. PMID:25706436

  8. Roles of tert-butyl formate, tert-butyl alcohol and acetone in the regulation of methyl tert-butyl ether degradation by Mycobacterium austroafricanum IFP 2012.

    PubMed

    François, A; Garnier, L; Mathis, H; Fayolle, F; Monot, F

    2003-08-01

    Mycobacterium austroafricanum IFP 2012 is a Gram-positive strain able to grow on methyl tert-butyl ether (MTBE) as a sole carbon and energy source. The effect of two downstream metabolites of MTBE, tert-butyl formate (TBF) and tert-butyl alcohol (TBA) on MTBE degradation was investigated using resting cells. The addition of low concentrations of TBF decreased the MTBE degradation rate by about 30%. In contrast, the addition of TBA did not have a significant effect on MTBE degradation rate, even at high concentrations; and it was also shown that TBA degradation occurred only once MTBE was exhausted. At neutral pH, TBF hydrolysis involved mainly an esterase-type activity regulated by the presence of TBA. The TBF degradation rate was about four times lower than the MTBE degradation rate. Furthermore, acetone was identified as an intermediate during TBA degradation. An acetone mono-oxygenase activity, inhibited by methimazole but not by acetylene, was suggested. It was different from the MTBE/TBA mono-oxygenase and, thus, acetone did not appear to compete with MTBE and TBA for the same enzyme. These new results show that the metabolic regulation of the early steps of MTBE degradation by M. austroafricanum IFP 2012 is complex, involving inhibition and competition phenomena. PMID:12883872

  9. A multi-class bioanalytical methodology for the determination of bisphenol A diglycidyl ethers, p-hydroxybenzoic acid esters, benzophenone-type ultraviolet filters, triclosan, and triclocarban in human urine by liquid chromatography-tandem mass spectrometry.

    PubMed

    Asimakopoulos, Alexandros G; Wang, Lei; Thomaidis, Nikolaos S; Kannan, Kurunthachalam

    2014-01-10

    A liquid-liquid extraction (LLE; ethyl acetate) protocol, followed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) methodology, was developed for the determination of 19 compounds, including bisphenol A diglycidyl ethers (BADGEs; industrial ethers), benzophenone-type UV filters (BP-UV filters; precursors and metabolites), p-hydroxybenzoic acid esters (parabens; preservatives), triclosan (TCS) and triclocarban (TCC) in human urine. Urine specimens were enzymatically deconjugated with β-glucuronidase (from Helix pomatia) and extracted by a LLE procedure for the measurement of total concentrations (i.e., free+conjugated forms) of target analytes. Absolute recoveries of BADGEs, BP-UV filters, parabens, TCS and TCC ranged 25-135%, 84-125%, 52-126%, 75-118% and 90-124%, respectively. Method precision (absolute values; N=5 replicate analyses at the fortification level of 10 ng, k=5 days) ranged from 5.8 (ethyl paraben) to 24.0% (TCS). The limits of quantification (LOQs) varied depending on the target compound and generally ranged from 0.2 to 2.0 ng/mL. The matrix effects ranged from +11 (2,3,4-trihydroxybenzophenone) to -86% (2,4-dihydroxybenzophenone). A total of 30 urine specimens collected from Athens, Greece, were analyzed for the 19 target compounds to demonstrate the applicability of the developed method. The concentrations of target chemicals in urine were presented on volume-, specific gravity (SG)-, and creatinine-normalization bases. MeP, EtP, PrP, OH-EtP, BADGE·2H2O, BP-1 and TCS were found frequently in urine at concentrations in the range of 2.7-436 ng/mL, <0.5-25.4 ng/mL, <0.5-575 ng/mL, <2-18.4 ng/mL, <0.5-13.8 ng/mL, <1-14.6 ng/mL and <0.5-95.3 ng/mL, respectively. PMID:24315674

  10. A nitrate ester of sedative alkyl alcohol improves muscle function and structure in a murine model of Duchenne muscular dystrophy.

    PubMed

    Wang, Guqi; Lu, Qilong

    2013-10-01

    Nitric oxide (NO) has major physiological and cellular effects on muscle growth, repair, and function. In most muscle biopsies from humans with myopathies, sarcolemma-localized neuronal nitric oxide synthase (nNOS) is either reduced or not detected, particularly in dystrophin-deficient Duchenne muscular dystrophy (DMD). Abnormal NO signaling at the sarcolemmal level is integrally involved in the pathogenesis and accounts, at least in part, for the muscle weakness of DMD. Dystrophic muscle fibers exhibit an increased susceptibility to contraction-induced membrane damage. Muscle relaxants function to prevent muscle wasting by decreasing nerve impulses and reducing calcium influx that regulates tensing or tightening of muscle fibers. We have recently developed a new class of nitric esters that combines the pharmacological functions of NO and muscle relaxation. Here, we report the synthesis and properties of the nitric ester (MMPN) of 2-methyl-2-n-propyl-1,3-propanediol (MPP) and its effect in mdx dystrophic mice, a murine model of DMD. MMPN produced significant improvements in biochemical, pathological, and functional phenotypes in the mouse model. The endurance of exercise was extended by 47% in time to exhaustion and 84% in running distance. Serum CK level was decreased by 30%. Additionally, MMPN decreased intracellular free calcium concentration without causing skeletal muscle weakness. No hepatic or renal toxicities were observed during the study. Our investigations unveil a potential new treatment for muscular diseases. PMID:23924275

  11. Alcohol

    MedlinePlus

    ... as well as injuries, liver disease, heart disease, cancer, and other health problems. It can also cause problems at home, at work, and with friends. NIH: National Institute on Alcohol Abuse and Alcoholism

  12. Lipoate ester multifunctional lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven lipoate esters were synthesized by esterification of lipoic acid with different structures of alcohols in the presence of a solid acid catalyst and without solvent. The esters were obtained in good yield, characterized using 1H NMR and GPC; and their physical properties investigated. Four of t...

  13. Synthesis of pyromellitic acid esters

    NASA Technical Reports Server (NTRS)

    Fedorova, V. A.; Donchak, V. A.; Martynyuk-Lototskaya, A. N.

    1985-01-01

    The ester acids necessary for studyng the thermochemical properties of pyromellitic acid (PMK)-based peroxides were investigated. Obtaining a tetramethyl ester of a PMK was described. The mechanism of an esterification reaction is discussed, as is the complete esterification of PMK with primary alcohol.

  14. Alcoholism.

    ERIC Educational Resources Information Center

    Caliguri, Joseph P., Ed.

    This extensive annotated bibliography provides a compilation of documents retreived from a computerized search of the ERIC, Social Science Citation Index, and Med-Line databases on the topic of alcoholism. The materials address the following areas of concern: (1) attitudes toward alcohol users and abusers; (2) characteristics of alcoholics and…

  15. Electron-transfer reaction of cinnamic acids and their methyl esters with the DPPH(*) radical in alcoholic solutions.

    PubMed

    Foti, Mario C; Daquino, Carmelo; Geraci, Corrada

    2004-04-01

    The kinetic behavior of cinnamic acids, their methyl esters, and two catechols 1-10 (ArOH) in the reaction with DPPH(*) in methanol and ethanol is not compatible with a reaction mechanism that involves hydrogen atom abstraction from the hydroxyl group of 1-10 by DPPH(*). The rate of this reaction at 25 degrees C is, in fact, comparatively fast despite that the phenolic OH group of ArOH is hydrogen bonded to solvent molecules. The observed rate constants (k(1)) relative to DPPH(*) + ArOH are 3-5 times larger for the methyl esters than for the corresponding free acids and, for the latter, decrease as their concentration is increased according to the relation k(1) = B/[ArOH](0)(m), where k(1) is given in units of M(-1) s(-1), m is ca. 0.5, and B ranges from 0.02 (p-coumaric acid) to ca. 3.48 (caffeic acid) in methanol and from 0.04 (p-coumaric acid) to ca. 13 (sinapic acid) in ethanol. Apparently, the reaction mechanism of DPPH(*) + ArOH involves a fast electron-transfer process from the phenoxide anion of 1-10 to DPPH(*). Kinetic analysis of the reaction sequence for the free acids leads to an expression for the observed rate constant, k(1), proportional to [ArOH](0)(-1/2) in excellent agreement with the experimental behavior of these phenols. The experimental results are also interpreted in terms of the influence that adventitious acids or bases present in the solvent may have. These impurities dramatically influence the ionization equilibrium of phenols and cause a reduction or an enhancement, respectively, of the measured rate constants. PMID:15049623

  16. Synergic effects in the extraction of paracetamol from aqueous NaCl solution by the binary mixtures of diethyl ether and low molecular weight primary alcohols

    NASA Astrophysics Data System (ADS)

    Nikolić, G. M.; Živković, J. V.; Atanasković, D. S.; Nikolić, M. G.

    2013-12-01

    Liquid-liquid extraction of paracetamol from aqueous NaCl solutions was performed with diethyl ether, 1-propanol, 1-butanol, isobutanol, 1-pentanol, and binary mixtures diethyl ether/1-propanol, diethyl ether/1-butanol, and diethyl ether/isobutanol. Among the pure solvents investigated in this study best extraction efficacy was obtained with 1-butanol. Synergic effects in the extraction with binary mixtures was investigated and compared with some other systems used for the extraction of poorly extractable compounds. Results obtained in this study may be of both fundamental and practical importance.

  17. Eugenol and isoeugenol, characteristic aromatic constituents of spices, are biosynthesized via reduction of a coniferyl alcohol ester

    PubMed Central

    Koeduka, Takao; Fridman, Eyal; Gang, David R.; Vassão, Daniel G.; Jackson, Brenda L.; Kish, Christine M.; Orlova, Irina; Spassova, Snejina M.; Lewis, Norman G.; Noel, Joseph P.; Baiga, Thomas J.; Dudareva, Natalia; Pichersky, Eran

    2006-01-01

    Phenylpropenes such as chavicol, t-anol, eugenol, and isoeugenol are produced by plants as defense compounds against animals and microorganisms and as floral attractants of pollinators. Moreover, humans have used phenylpropenes since antiquity for food preservation and flavoring and as medicinal agents. Previous research suggested that the phenylpropenes are synthesized in plants from substituted phenylpropenols, although the identity of the enzymes and the nature of the reaction mechanism involved in this transformation have remained obscure. We show here that glandular trichomes of sweet basil (Ocimum basilicum), which synthesize and accumulate phenylpropenes, possess an enzyme that can use coniferyl acetate and NADPH to form eugenol. Petunia (Petunia hybrida cv. Mitchell) flowers, which emit large amounts of isoeugenol, possess an enzyme homologous to the basil eugenol-forming enzyme that also uses coniferyl acetate and NADPH as substrates but catalyzes the formation of isoeugenol. The basil and petunia phenylpropene-forming enzymes belong to a structural family of NADPH-dependent reductases that also includes pinoresinol–lariciresinol reductase, isoflavone reductase, and phenylcoumaran benzylic ether reductase. PMID:16782809

  18. Evaluating UV/H2O2 processes for methyl tert-butyl ether and tertiary butyl alcohol removal: effect of pretreatment options and light sources.

    PubMed

    Li, Ke; Hokanson, David R; Crittenden, John C; Trussell, Rhodes R; Minakata, Daisuke

    2008-12-01

    In this paper, we evaluate the efficiency of UV/H2O2 process to remove methyl tert-butyl ether (MtBE) and tertiary butyl alcohol (tBA) from a drinking water source. Kinetic models were used to evaluate the removal efficiency of the UV/H2O2 technologies with different pretreatment options and light sources. Two commercial UV light sources, i.e. low pressure, high intensity lamps and medium pressure, high intensity lamps, were evaluated. The following pretreatment alternatives were evaluated: (1) ion exchange softening with seawater regeneration (NaIX); (2) Pellet Softening; (3) weak acid ion exchange (WAIX); and (4) high pH lime softening followed by reverse osmosis (RO). The presence or absence of a dealkalization step prior to the UV/H2O2 Advanced Oxidation Process (AOP) was also evaluated for each pretreatment possibility. Pretreatment has a significant impact on the performance of UV/H2O2 process. The NaIX with dealkalization was shown to be the most cost effective. The electrical energy per order (EEO) values for MtBE and tBA using low pressure high output UV lamps (LPUV) and 10mg/LH2O2 are 0.77 and 3.0 kWh/kgal-order, or 0.20 and 0.79 kWh/m3-order, respectively. For medium pressure UV high output lamps (MPUV), EEO values for MtBE and tBA are 4.6 and 15 kWh/kgal-order, or 1.2 and 4.0 kWh/m3-order, for the same H2O2 dosage. PMID:18951605

  19. Degradation kinetics of poly(ether-urethane) Estane® induced by electron irradiation

    NASA Astrophysics Data System (ADS)

    Dannoux, A.; Esnouf, S.; Begue, J.; Amekraz, B.; Moulin, C.

    2005-07-01

    Radiation effects on a segmented aromatic poly(ether-urethane) induced by electron beam irradiation under oxygen atmosphere were investigated using Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR) in order to determine the degradation mechanisms. Thin films have been irradiated under a dose rate of 1 MGy/h with absorbed doses varying from 25 to 1000 kGy under O2. FTIR spectra have shown the formation of hydroperoxides, carboxylic acids, primary amines, alcohols, esters and formates. Moreover, the decrease of urethane and ether absorbances revealed the degradation of both soft and hard segments. Spin-trapping technique was used to monitor the evolution of short-lived peroxy and alkyl radicals at room temperature. Finally, a mechanism of degradation for electron irradiated polyurethane is proposed.

  20. Quantification of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in meconium from newborns for detection of alcohol abuse in a maternal health evaluation study.

    PubMed

    Bakdash, Abdulsallam; Burger, Pascal; Goecke, Tamme W; Fasching, Peter A; Reulbach, Udo; Bleich, Stefan; Hastedt, Martin; Rothe, Michael; Beckmann, Matthias W; Pragst, Fritz; Kornhuber, Johannes

    2010-04-01

    Fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) were determined in 602 meconium samples in a maternal health evaluation study for detection of gestational alcohol consumption. A validated headspace solid phase microextraction method in combination with GC-MS was used for FAEE and the cumulative concentration of ethyl palmitate, ethyl linoleate, ethyl oleate, and ethyl stearate with a cut-off of 500 ng/g was applied for interpretation. A new and simple method was developed and validated for quantification of EtG from 10-20 mg meconium with D(5)-EtG as internal standard consisting of 30 min. extraction with methanol/water (1:1, v/v), evaporation of methanol, filtration of the aqueous solution through a cellulose filter and injection into LC-MS-MS. The limits of detection and quantification for EtG were 10 and 30 ng/g, the recovery 86.6 to 106.4% and the standard deviation of the concentrations ranged from 13% at 37 ng/g to 5% at 46,700 ng/g (N = 6). FAEE above the cut-off were found in 43 cases (7.1%) with cumulative concentrations between 507 and 22,580 ng/g and with one outlier of about 150,000 ng/g (EtG not detected). EtG was detected in 97 cases (16.3%) and concentrations between LOD and 10,200 ng/g with another outlier of 82,000 ng/g (FAEE 10,500 ng/g). Optimal agreement between the two markers was obtained with a cut-off for EtG of 274 ng/g and 547 cases with both FAEE- and EtG-negative, 33 cases with both FAEE- and EtG-positive, nine cases with FAEE-positive and EtG-negative, and seven cases with FAEE-negative and EtG-positive. Differences in physical, chemical, and biochemical properties and in the pharmacokinetic behavior are discussed as reasons for the deviating cases. In none of the 602 cases, serious alcohol consumption was reported by the mothers and no evidence for gestational ethanol exposure was observed in the medical investigation of the newborns. It is concluded that the combined use of FAEE and EtG in meconium as markers for fetal

  1. Improved boundary lubrication with formulated C-ethers

    NASA Technical Reports Server (NTRS)

    Loomis, W. R.

    1982-01-01

    A comparison of five recently developed C-ether-formulated fluids with an advanced formulated MIL-L-27502 candidate ester is described. Steady state wear and friction measurements were made with a sliding pin on disk friction apparatus. Conditions included disk temperatures up to 260 C, dry air test atmosphere, 1 kilogram load, 50 rpm disk speed, and test times to 130 minutes. Based on wear rates and coefficients of friction, three of the C-ether formulations as well as the C-ether base fluid gave better boundary lubrication than the ester fluid under all test conditions. The susceptibility of C-ethers to selective additive treatment (phosphinic esters or acids and other antiwear additives) was demonstrated when two of the formulations gave somewhat improved lubrication over the base fluid. The increased operating potential for this fluid was shown in relationship to bulk oil temperature limits for MIL-L-23699 and MIL-L-27502 type esters.

  2. Alkyl Aryl Ether Bond Formation with PhenoFluor**

    PubMed Central

    Shen, Xiao; Neumann, Constanze N.; Kleinlein, Claudia; Claudia, Nathaniel W.; Ritter, Tobias

    2015-01-01

    An alkyl aryl ether bond formation reaction between phenols and primary and secondary alcohols with PhenoFluor has been developed. The reaction features a broad substrate scope and tolerates many functional groups, and substrates that are challenging for more conventional ether bond forming processes may be coupled. A preliminary mechanistic study indicates reactivity distinct from conventional ether bond formation. PMID:25800679

  3. Alcohol.

    ERIC Educational Resources Information Center

    Schibeci, Renato

    1996-01-01

    Describes the manufacturing of ethanol, the effects of ethanol on the body, the composition of alcoholic drinks, and some properties of ethanol. Presents some classroom experiments using ethanol. (JRH)

  4. Rapid determination of phthalate esters in alcoholic beverages by conventional ionic liquid dispersive liquid-liquid microextraction coupled with high performance liquid chromatography.

    PubMed

    Fan, Yingying; Liu, Shuhui; Xie, Qilong

    2014-02-01

    A very simple, fast and environmentally friendly sample extraction method was proposed for the analysis of phthalate esters (PAEs, di-isobutyl phthalate (DIBP), dibutylphthalate (DBP), butylbenzylphthalate (BBP) and bis(2-ethylhexyl)phthalate (DEHP)) in alcoholic beverages by using conventional ionic liquid dispersive liquid-liquid microextraction. The samples were extracted by 160 μL 1-octyl-3-methylimidazolium hexafluorophosphate in the presence of appropriate amount of ethanol and 10% (w/v) sodium chloride solution; the enriched analytes in sedimented phases were analyzed by high performance liquid chromatography-diode array detector (HPLC-DAD). Under the optimum conditions, a satisfactory linearity (in the range of 0.02-1 μg mL(-1) for white spirits and 0.01-0.5 μg mL(-1) for red wines with the correlation coefficients (r) varying from 0.9983 to 1), acceptable recovery rates (88.5-103.5% for white spirits and 91.6-104.6% for red wines), good repeatability (RSD ≤ 8.0%) and low detection limits (3.1-4.2 ng mL(-1) for white spirits and 1.5-2.2 ng mL(-1) for red wines) were obtained. The developed method was successfully applied for the determination of the four PAEs in 30 white spirits and 11 red wines collected locally, and the DBP content in 63% (19:30) white spirits exceeded the specific migration limit of 0.3 mg kg(-1) established by international regulation. PMID:24401417

  5. Measurement of methyl tert-butyl ether and tert-butyl alcohol in human blood by purge-and-trap gas chromatography-mass spectrometry using an isotope-dilution method.

    PubMed

    Bonin, M A; Ashley, D L; Cardinali, F L; McCraw, J M; Wooten, J V

    1995-01-01

    We developed an isotope-dilution method for measuring methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) in whole human blood using a purge-and-trap gas chromatographic-mass spectrometric method. The labeled analogues for MTBE and TBA were [2H12]methyl tert-butyl ether and [2H9]-tert-butyl alcohol, respectively. Volatiles were removed from the blood by direct helium purging of the liquid; were trapped on a Tenax trap; and were desorbed, cryofocused, and chromatographed on a DB-624 capillary column that was connected directly to the ion source of a mass spectrometer. Detection was by mass analysis using a double-focusing magnetic-sector mass spectrometer operating in the full-scan mode at the medium mass resolution of 3000. For the isotope-dilution method, the minimum detection limits in blood (5-10 mL) are 0.01 microgram/L for MTBE and 0.06 microgram/L for TBA. The isotope-dilution method proved to be a big improvement in recovery, reproducibility, and sensitivity over our previous analytical method, which used the labeled ketone, [4-2H3]-2-butanone, as the internal standard for both MTBE and TBA. The isotope-dilution method has sufficient sensitivity for monitoring blood levels of MTBE and TBA in populations exposed to oxygenated fuels containing MTBE. PMID:7564298

  6. Steady-state boundary lubrication with formulated C-ethers to 260 C

    NASA Technical Reports Server (NTRS)

    Loomis, W. R.

    1981-01-01

    Steady state wear and friction studies were made at boundary lubrication conditions in a pin on disk (pure iron on rotating CVM M 50 steel) sliding friction apparatus with five C ether formulated fluids (modified polyphenyl ether containing phosphrous ester, organic acid, and other additives). Conditions included 20, 150, and 260 C disk temperatures, dry air test atmosphere, 1 kilogram load, 50 rpm disk speed, and test times to 130 minutes. Results were compared with those obtained with a formulated MIL L 27502 candidate ester and the C ether base fluid. Three of the C ether formulations gave better lubrication than both reference fluids under most conditions. The other two C ether formulations yielded higher wear rates and friction coefficients than the C ether base fluid for most of the temperature range. Only one C ether formulation showed consistently higher steady state wear rates than the ester.

  7. An innovative arrangement for in-vial membrane-assisted liquid-liquid microextraction: application to the determination of esters of phthalic acid in alcoholic beverages by gas chromatography-mass spectrometry.

    PubMed

    March, Juan Gabriel; Cerdà, Victor

    2015-05-01

    A new arrangement for membrane-assisted liquid-liquid microextraction is presented. The extracting organic solvent was placed into a chromatographic microvial, compatible with the chromatograph autosampler, whose septum was replaced by a disc of porous hydrophobic membrane. This extraction device was completely immersed into the analytical sample contained in a cylindrical container subjected to rotary and basculant movement. Then, the extraction of analytes took place from the sample to the organic solvent contained in the vial through the membrane. Esters of the phthalic acid have been selected as model analytes to determine the performance characteristics of the extraction system. The limits of detection, limits of quantification and relative standard deviations (%) were in the range 0.1-0.4, 0.3-1 and 4-7, respectively. Esters of phthalic acid have been successfully analysed in alcoholic beverages. The main operational advantages of this arrangement consisted of minimal required handling, minimal risk of cross contamination and its simplicity. PMID:25876533

  8. Synthesis and pharmacological evaluation of some dual-acting amino-alcohol ester derivatives of flurbiprofen and 2-[1,1'-biphenyl-4-yl]acetic acid: a potential approach to reduce local gastrointestinal toxicity.

    PubMed

    Halen, Parmeshwari Kuldeep Kumar; Chagti, Kewal Krishna; Giridhar, Rajani; Yadav, Mange Ram

    2006-11-01

    The search for safer non-steroidal anti-inflammatory drugs (NSAIDs) continues with the failure of anticipated 'ideal' anti-inflammatory agents, the coxibs, on long-term usage. Increased gastric motility and acidity due to the free carboxy group are involved in the etiology of gastric toxicity, common to conventional NSAIDs. Keeping this fact in mind, it was planned to modify some of the conventional NSAIDs to amino-alcohol ester derivatives, which satisfied the structural requirements for these compounds to possess anticholinergic activity in the intact form. Besides blocking the acidic carboxylic group, incorporation of anticholinergic acivity in these molecules was expected to reduce the gastric toxicity by decreasing gastric acid secretion and motility. Synthesis and pharmacological evaluation of six different N,N-disubstituted amino-ethyl ester derivatives, structurally resembling the amino-alcohol ester class of anticholinergic agents, each for [1,1'-biphenyl]-4-acetic acid (3) and flurbiprofen (10), have been reported as potential substitutes for these NSAIDs, with improved therapeutic profile. All the ester derivatives were found to have sufficient chemical stability in buffers (pH 2.0 and 7.4), ensuring them to be absorbed as intact moieties from the gastrointestinal tract. A significant reduction in ulcerogenic potency in comparison to the parent drugs with a slightly higher anti-inflammatory potency suggests that the majority of these candidates have an improved therapeutic profile over their parent drugs. Hence, a promising novel approach, different from the conventional prodrug concept, has been successfully worked out to overcome the local gastric toxicity, yielding therapeutically better compounds for long-term oral anti-inflammatory therapy. PMID:17193237

  9. Fatty Aldehyde and Fatty Alcohol Metabolism: Review and Importance for Epidermal Structure and Function

    PubMed Central

    Rizzo, William B.

    2014-01-01

    Normal fatty aldehyde and alcohol metabolism is essential for epidermal differentiation and function. Long-chain aldehydes are produced by catabolism of several lipids including fatty alcohols, sphingolipids, ether glycerolipids, isoprenoid alcohols and certain aliphatic lipids that undergo α- or ω-oxidation. The fatty aldehyde generated by these pathways is chiefly metabolized to fatty acid by fatty aldehyde dehydrogenase (FALDH, alternately known as ALDH3A2), which also functions to oxidize fatty alcohols as a component of the fatty alcohol:NAD oxidoreductase (FAO) enzyme complex. Genetic deficiency of FALDH/FAO in patients with Sjögren-Larsson syndrome (SLS) results in accumulation of fatty aldehydes, fatty alcohols and related lipids (ether glycerolipids, wax esters) in cultured keratinocytes. These biochemical changes are associated with abnormalities in formation of lamellar bodies in the stratum granulosum and impaired delivery of their precursor membranes to the stratum corneum (SC). The defective extracellular SC membranes are responsible for a leaky epidermal water barrier and ichthyosis. Although lamellar bodies appear to be the pathogenic target for abnormal fatty aldehyde/alcohol metabolism in SLS, the precise biochemical mechanisms are yet to be elucidated. Nevertheless, studies in SLS highlight the critical importance of FALDH and normal fatty aldehyde/alcohol metabolism for epidermal function. PMID:24036493

  10. Pentabromodiphenyl ether

    Integrated Risk Information System (IRIS)

    Pentabromodiphenyl ether ; CASRN 32534 - 81 - 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 Noncar

  11. Hexabromodiphenyl ether

    Integrated Risk Information System (IRIS)

    Hexabromodiphenyl ether ; CASRN 36483 - 60 - 0 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 Noncarc

  12. Ethyl ether

    Integrated Risk Information System (IRIS)

    Ethyl ether ; CASRN 60 - 29 - 7 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 Effect

  13. Tetrabromodiphenyl ether

    Integrated Risk Information System (IRIS)

    Tetrabromodiphenyl ether ; CASRN 40088 - 47 - 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 Noncar

  14. Nonabromodiphenyl ether

    Integrated Risk Information System (IRIS)

    Nonabromodiphenyl ether ; CASRN 63936 - 56 - 1 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 Noncarc

  15. Tribromodiphenyl ether

    Integrated Risk Information System (IRIS)

    Tribromodiphenyl ether ; CASRN 49690 - 94 - 0 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 Noncarci

  16. Octabromodiphenyl ether

    Integrated Risk Information System (IRIS)

    Octabromodiphenyl ether ; CASRN 32536 - 52 - 0 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 Noncarc

  17. Application of the intramolecular isomerisation-aldolisation from allylic alcohols and allylic silyl ethers to the synthesis of indanones and indenones.

    PubMed

    Petrignet, Julien; Roisnel, Thierry; Grée, René

    2007-01-01

    A new access to indanones was discovered through a one-step nickel or iron-mediated transposition of 2-hydroxyisobenzofurans. Starting from the corresponding silylenol ethers, a new one-pot tandem isomerisation-Mukaiyama aldol process was also developed. These versatile strategies will be useful for the preparation of various types of indanones and indenones. PMID:17579904

  18. Scattering and Spectroscopic Study on the Hydration and Phase Behavior of Aqueous Alcohol Ethoxylate and Methyl Ester Ethoxylate: Effects of Terminal Groups in Hydrophilic Chains.

    PubMed

    Sato, Takaaki; Akahane, Takesi; Amano, Kenshi; Hyodo, Ryo; Yanase, Keiichi; Ogura, Taku

    2016-06-23

    Using dielectric relaxation spectroscopy (DRS), small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and viscometry, we have investigated the hydration behavior, static structures, Brownian dynamics, and mechanical properties of aqueous solutions of alcohol ethoxylate (C12E15) and methyl ester ethoxylate (C12MEE), hereafter abbreviated as AE and MEE, respectively, in which we especially focus on the effects of the endcaps of these nonionic surfactants. We find that AE and MEE exhibit fairly different phase behaviors in water: AE produces liquid crystalline phases at w (surfactant weight fraction) > 0.35, whereas MEE retains a liquid phase in an extremely wide concentration range (w < 0.7) at ambient temperature. The structure factor deduced from SAXS intensities using a generalized indirect Fourier transformation technique and the effective hydration number evaluated from the negative excess bulk water relaxation amplitude revealed by DRS unambiguously demonstrate that hydration water molecules, exhibiting about 4-times-slower collective reorientational dynamics than that of bulk water, contribute to the excluded volume of the micelles. The blocked terminal hydrogen-bond donor/acceptor site of MEE leads to smaller hydration number of MEE than compared to that of AE, and consequently the lower excluded volume of the MEE micelles. The effective micellar volume fraction, ϕ(eff), should be defined by incorporating such different hydration effects. Importantly, voluminosity, defined as the micellar volume fraction per unit mass, is clearly a decreasing function of w, demonstrating progressive dehydration at a higher w. The collective diffusion constants determined by DLS for the AE and MEE micelles show a monotonous increase up to ϕ(eff) ≈ 0.5, as expected for the hard spheres. Low-shear-rate viscosities follow a Krieger-Dougherty model in the identical micellar packing fraction range. All static, dynamic, and mechanical properties of these micellar

  19. Boundary lubrication of formulated C-ethers in air to 300 C

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1975-01-01

    Friction and wear measurements were made in dry and moist air on CVM M-50 steel lubricated with six C-ether formulations containing phosphorus ester and organic acid additives. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, 17 meter-per-minute (100 rpm) surface speed, and a 25 to 300 C disk temperature range. The C-ether base fluid and the C-ether formulations yielded lower wear than the ester under most test conditions. The C-ether formulations exhibited higher friction coefficients than the ester from 150 to 300 C and similar or lower values from 25 to 150 C.

  20. Production and biological function of volatile esters in Saccharomyces cerevisiae

    PubMed Central

    Saerens, Sofie M. G.; Delvaux, Freddy R.; Verstrepen, Kevin J.; Thevelein, Johan M.

    2010-01-01

    Summary The need to understand and control ester synthesis is driven by the fact that esters play a key role in the sensorial quality of fermented alcoholic beverages like beer, wine and sake. As esters are synthesized in yeast via several complex metabolic pathways, there is a need to gain a clear understanding of ester metabolism and its regulation. The individual genes involved, their functions and regulatory mechanisms have to be identified. In alcoholic beverages, there are two important groups of esters: the acetate esters and the medium‐chain fatty acid (MCFA) ethyl esters. For acetate ester synthesis, the genes involved have already been cloned and characterized. Also the biochemical pathways and the regulation of acetate ester synthesis are well defined. With respect to the molecular basis of MCFA ethyl ester synthesis, however, significant progress has only recently been made. Next to the characterization of the biochemical pathways and regulation of ester synthesis, a new and more important question arises: what is the advantage for yeast to produce these esters? Several hypotheses have been proposed in the past, but none was satisfactorily. This paper reviews the current hypotheses of ester synthesis in yeast in relation to the complex regulation of the alcohol acetyl transferases and the different factors that allow ester formation to be controlled during fermentation. PMID:21255318

  1. The Absolute Rates of the Solution Phase Addition of Atomic Hydrogen to a Vinyl Ether and a Vinyl Ester. The Effect of Oxygen Substitution on Hydrogen Atom Reactivity with Olefins

    SciTech Connect

    Tanner, D. D.; Kandanarachchi, P.; Das, N. C.; Franz, James A.

    2003-04-08

    The reactions of vinyl butyl ether and vinyl butyrate with atomic hydrogen and deuterium lead to addition of atomic hydrogen to the terminal position of the olefins. This observation is consistent with the reactions carried out earlier with other olefins. Both the absolute rates of addition to vinylbutyl ether and vinyl butyrate in acetone and hexane were carried out at several temperatures. The relative rates are consistent with only modest stabilization of the transition state of the radical adduct by the ??-o substituent compared with hydrogen atom addition to 1-octene. The relative rates measured in acetone and hexane indicate no significant differential solvation of ground state relative to the transition structures of the hydrogen atom addition. The kinetics reveal that the early transition states of hydrogen atom addition exhibit little selectivity (vinyl ether versus simple olefin) in either abstraction of hydrogen ??- to the oxygen or by terminal addition to the olefinic ether, reflecting the modest influence of the increased enthalpy of reaction associated with resonance stabilization by the oxygen substituent at the developing radical site.

  2. Absolute Rates of the Solution-Phase Addition of Atomic Hydrogen to a Vinyl Ether and a Vinyl Ester: Effect of Oxygen Substitution on Hydrogen Atom Reactivity with Olefins

    SciTech Connect

    Tanner, D D.; Kandanarachchi, P; Das, N. C.; Franz, James A.

    2003-04-08

    The reactions of vinyl butyl ether and vinyl butyrate with atomic hydrogen and deuterium lead to addition at the terminal position of the olefins. This observation is consistent with the reactions carried out earlier with other olefins. Both of the absolute rates of addition to vinylbutyl ether and vinyl butyrate, in acetone and hexane, were measured at several temperatures. The relative rates are consistent with only modest stabilization of the transition state of the radical adduct by the R-O substituent compared with that of hydrogen atom addition to 1-octene. The relative rates measured in acetone and hexane indicate no significant differential solvation of the ground state relative to the transition structures of the hydrogen atom addition. The kinetics reveal that the early transition states for hydrogen atom addition exhibit little selectivity (vinyl ether versus simple olefin) in either the abstraction of hydrogen R to the oxygen or by terminal addition to the olefinic ether and reflects the modest influence of the increased enthalpy of reaction associated with resonance stabilization by the oxygen substituent at the developing radical site.

  3. Process for making propenyl ethers and photopolymerizable compositions containing them

    DOEpatents

    Crivello, James V.

    1996-01-01

    Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  4. Process for making propenyl ethers and photopolymerizable compositions containing them

    DOEpatents

    Crivello, J.V.

    1996-01-23

    Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} (V) wherein n is an integer from one to six and A is selected from cyclic ethers, polyether, and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  5. GC/GCMS analysis of the petroleum ether and dichloromethane extracts of Moringa oleifera roots

    PubMed Central

    Faizi, Shaheen; Sumbul, Saima; Versiani, Muhammed Ali; Saleem, Rubeena; Sana, Aisha; Siddiqui, Hira

    2014-01-01

    Objective To explore the phytochemical constituents from petroleum ether and dichloromethane extracts of Moringa oleifera (M. oleifera) roots using GC/GC-MS. Methods A total of 5.11 kg fresh and undried crushed root of M. oleifera were cut into small pieces and extracted with petroleum ether and dichloromethane (20 L each) at room temperature for 2 d. The concentrated extracts were subjected to their GC-MS analysis. Results The GC-MS analysis of the petroleum ether and dichloromethane extracts of M. oleifera roots, which showed promising biological activities, has resulted in the identification 102 compounds. These constituents belong to 15 classes of compounds including hydrocarbons, fatty acids, esters, alcohols, isothiocyanate, thiocyanate, pyrazine, aromatics, alkamides, cyanides, steroids, halocompounds, urea and N-hydroxyimine derivatives, unsaturated alkenamides, alkyne and indole. GC/GC-MS studies on petroleum ether extract of the roots revealed that it contained 39 compounds, belonging to nine classes. Cyclooctasulfur S8 has been isolated as a pure compound from the extract. The major compounds identified from petroleum ether extract were trans-13-docosene (37.9%), nonacosane (32.6%), cycloartenol (28.6%) nonadecanoic acid (13.9%) and cyclooctasulfur S8 (13.9%). Dichloromethane extract of the roots was composed of 63 compounds of which nasimizinol (58.8%) along with oleic acid (46.5%), N-benzyl-N-(7-cyanato heptanamide (38.3%), N-benzyl-N-(1-chlorononyl) amide (30.3%), bis [3-benzyl prop-2-ene]-1-one (19.5%) and N, N-dibenzyl-2-ene pent 1, 5-diamide (11.6%) were the main constituents. Conclusions This study helps to predict the formula and structure of active molecules which can be used as drugs. This result also enhances the traditional usage of M. oleifera which possesses a number of bioactive compounds. PMID:25183335

  6. Development of Enantiospecific Coupling of Secondary and Tertiary Boronic Esters with Aromatic Compounds.

    PubMed

    Odachowski, Marcin; Bonet, Amadeu; Essafi, Stephanie; Conti-Ramsden, Philip; Harvey, Jeremy N; Leonori, Daniele; Aggarwal, Varinder K

    2016-08-01

    The stereospecific cross-coupling of secondary boronic esters with sp(2) electrophiles (Suzuki-Miyaura reaction) is a long-standing problem in synthesis, but progress has been achieved in specific cases using palladium catalysis. However, related couplings with tertiary boronic esters are not currently achievable. To address this general problem, we have focused on an alternative method exploiting the reactivity of a boronate complex formed between an aryl lithium and a boronic ester. We reasoned that subsequent addition of an oxidant or an electrophile would remove an electron from the aromatic ring or react in a Friedel-Crafts-type manner, respectively, generating a cationic species, which would trigger 1,2-migration of the boron substituent, creating the new C-C bond. Elimination (preceded by further oxidation in the former case) would result in rearomatization giving the coupled product stereospecifically. Initial work was examined with 2-furyllithium. Although the oxidants tested were unsuccessful, electrophiles, particularly NBS, enabled the coupling reaction to occur in good yield with a broad range of secondary and tertiary boronic esters, bearing different steric demands and functional groups (esters, azides, nitriles, alcohols, and ethers). The reaction also worked well with other electron-rich heteroaromatics and 6-membered ring aromatics provided they had donor groups in the meta position. Conditions were also found under which the B(pin)- moiety could be retained in the product, ortho to the boron substituent. This protocol, which created a new C(sp(2))-C(sp(3)) and an adjacent C-B bond, was again applicable to a range of secondary and tertiary boronic esters. In all cases, the coupling reaction occurred with complete stereospecificity. Computational studies verified the competing processes involved and were in close agreement with the experimental observations. PMID:27384259

  7. Carboxylic Acid Esters as Substrates of Cholinesterases

    NASA Astrophysics Data System (ADS)

    Brestkin, A. P.; Rozengart, E. V.; Abduvakhabov, A. A.; Sadykov, A. A.

    1983-10-01

    Data on the kinetics of the hydrolysis of various carboxylic acid esters by two main types of cholinesterases — acetylcholinesterase from human erythrocytes and butyrylcholinesterase from horse blood serum — are surveyed. It is shown that the rate of enzyme hydrolysis depends significantly on the structure of the acyl part of the ester molecule, the nature of the ester heteroatom, the structure of the alcohol component, and particularly the structure of the onium group. Esters based on natural products are of special interest as specific substrates of these enzymes. The role of the productive and non-productive sorption of the substrates in enzyme catalysis is demonstrated. The bibliography includes 81 references.

  8. Asymmetric Brønsted Acid Catalyzed Substitution of Diaryl Methanols with Thiols and Alcohols for the Synthesis of Chiral Thioethers and Ethers.

    PubMed

    Chatupheeraphat, Adisak; Liao, Hsuan-Hung; Mader, Steffen; Sako, Makoto; Sasai, Hiroaki; Atodiresei, Iuliana; Rueping, Magnus

    2016-04-01

    An enantioselective addition of thiols and alcohols to aza-ortho-quinone methides, starting from diaryl methanols, was developed. The asymmetric additions occur under mild reaction conditions in the presence of chiral phosphoric acids and furnish the corresponding adducts with excellent yields and enantioselectivities. PMID:26952288

  9. Synthesis and low temperature characterization of iso-oleic ester derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three new iso-oleic ester derivatives (i.e., isopropyl esters (IOA-iPrE), n-butyl esters (IOA-n-BuE), and 2-ethylhexyl esters (IOA-2-EHE)) were synthesized from iso-oleic acid (IOA) using a standard esterification method. These esterified alcohols were chosen because of their bulky and branched-cha...

  10. The synthesis of (Z)-trisubstituted allylic alcohols by the selective 1,4-hydrogenation of dienol esters: improved synthesis of (-)-β-santalol.

    PubMed

    Fehr, Charles; Magpantay, Iris; Vuagnoux, Magali; Dupau, Philippe

    2011-01-24

    (E)-Trisubstituted allylic alcohols are commonly prepared from the corresponding (E)-enals, themselves readily accessible by a simple aldol condensation reaction. We demonstrate that these very same (E)-enals can be converted into (Z)-trisubstituted allylic acetates (and thus alcohols) by a ruthenium-catalyzed 1,4-hydrogenation of the corresponding dienol acetates. This simple solution to a long-lasting problem was applied to an industrially feasible synthesis of (-)-β-santalol. PMID:21243692

  11. Wax ester-synthesizing activity of lipases.

    PubMed

    Tsujita, T; Sumiyoshi, M; Okuda, H

    1999-11-01

    The synthesis/hydrolysis of wax esters was studied in an aqueous solution using purified rat pancreatic lipase, porcine pancreatic carboxylester lipase, and Pseudomonas fluorescens lipase. The equilibrium between wax ester synthesis and hydrolysis favored ester formation at neutral pH. The synthesizing activities were measured using free fatty acid or triacylglycerol as the acyl donor and an equimolar amount of long-chain alcohol as the acyl acceptor. When oleic acid and hexadecanol emulsified with gum arabic were incubated with these lipases, wax ester was synthesized, in a dose- and time-dependent manner, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was about 0.9/0.1. These lipases catalyzed the hydrolysis of palmityl oleate emulsified with gum arabic, and the apparent equilibrium ratio of palmityl oleate/free oleic acid was also about 0.9/0.1. The apparent equilibrium ratio of wax ester/free fatty acid catalyzed by lipase depended on incubation pH and fatty alcohol chain length. When equimolar amounts of trioleoylglycerol and fatty acyl alcohol were incubated with pancreatic lipase, carboxylester lipase, or P. fluorescens lipase, wax esters were synthesized dose-dependently. These results suggest that lipases can catalyze the synthesis of wax esters from free fatty acids or through degradation of triacylglycerol in an aqueous medium. PMID:10606038

  12. Preparation and characterization of novel crown ether functionalized ionic liquid-based solid-phase microextraction coatings by sol-gel technology.

    PubMed

    Zhou, Xin; Xie, Peng-fei; Wang, Jiang; Zhang, Bei-bei; Liu, Ming-ming; Liu, Han-lan; Feng, Xiong-han

    2011-06-10

    A novel crown ether functionalized ionic liquid (IL), 1-allyl-3-(6'-oxo-benzo-15-crown-5 hexyl) imidazolium hexafluorophosphate was synthesized and used as selective stationary phase to prepare task-specific IL-based solid phase microextraction (SPME) fibers by sol-gel method and free radical cross-linking technology. The underlying mechanism of the sol-gel reaction was proposed and the successful chemical bonding of the crown ether functionalized IL to the formed hybrid organic-inorganic copolymer coating was confirmed by FT-IR spectroscopy. The performance of this in situ created crown ether functionalized IL-based SPME fibers, was investigated in detail. The coating has porous surface structure, stable performance in high temperature (to 340 °C) and in different solutions (water, organic solvent, acid and alkali), and good coating preparation reproducibility. In contrast to the sol-gel derived 1-allyl-3-methyl imidazolium hexafluorophosphate-based coating prepared in our previous work with the identical procedure, the extraction performance of this newly developed sol-gel crown ether functionalized IL-based coating was superior for alcohols, phthalate esters, phenolic environmental estrogens, fatty acids and aromatic amines due to the introduction of benzo-15-crown-5 functional group in IL structure. Moreover, it was shown to provide higher or comparable extraction efficiencies for most analytes studied than did the commercial PDMS, PDMS/DVB and PA fibers. PMID:21531419

  13. Antioxidant activity of alkyl hydroxytyrosyl ethers in unsaturated lipids.

    PubMed

    Cert, Rosa; Madrona, Andrés; Espartero, José Luis; Pérez-Camino, M Carmen

    2015-06-01

    The antioxidant activity of ethyl and octyl hydroxytyrosyl ethers toward lipids was determined using the Rancimat and open cup methods at high temperatures and 50 °C, respectively. The effect of the unsaturation of the matrix was evaluated using sunflower, soya, and fish refined oils. The antioxidant activities of alkyl hydroxytyrosyl ethers (HTy ethers), hydroxytyrosyl esters, and free hydroxytyrosol are similar, and are much higher than that of α-tocopherol at the same millimolar concentration. The relationship between the induction period and the concentration of the HTy ethers is a sigmoidal curve; an accurate concentration of HTy ethers is necessary to achieve maximum activity, as it increases with the level of matrix unsaturation. The presence of tocopherols in commercial oils affects the antioxidant effect of HTy ethers. Thus, the addition of a low concentration of HTy ethers results in a positive effect, whereas the effect of the addition of high amounts of ethers is slightly less than that of the phenol alone. The addition of HTy ethers to commercial refined oils increases the stability of the oils and preserves tocopherols and polyunsaturated fatty acids from oxidation, enabling the oils to maintain their nutritional properties for longer periods of time. PMID:26018773

  14. Methods of making alkyl esters

    DOEpatents

    Elliott, Brian

    2010-08-03

    A method comprising contacting an alcohol, a feed comprising one or more glycerides and equal to or greater than 2 wt % of one or more free fatty acids, and a solid acid catalyst, a nanostructured polymer catalyst, or a sulfated zirconia catalyst in one or more reactors, and recovering from the one or more reactors an effluent comprising equal to or greater than about 75 wt % alkyl ester and equal to or less than about 5 wt % glyceride.

  15. Phase Behavior of Poly(vinylidene fluoride)-graft-poly(diethylene glycol methyl ether methacrylate) in Alcohol-Water System: Coexistence of LCST and UCST.

    PubMed

    Kuila, Atanu; Maity, Nabasmita; Chatterjee, Dhruba P; Nandi, Arun K

    2016-03-10

    A thermoresponsive polymer poly(diethylene glycol methyl ether methacrylate) (PMeO2MA) is grafted from poly(vinylidene fluoride) (PVDF) backbone by using a combined ATRC and ATRP technique with a high conversion (69%) of the monomer to produce the graft copolymer (PD). It is highly soluble polymer and its solution property is studied by varying polarity in pure solvents (water, methanol, isopropanol) and also in mixed solvents (water-methanol and water-isopropanol) by measuring the hydrodynamic size (Z-average) of the particles by dynamic light scattering (DLS). The variation of Z-average size with temperature of the PD solution (0.2%, w/v) indicates a lower critical solution temperature (LCST)-type phase transition (T(PL)) in aqueous medium, an upper critical solution temperature (UCST)-type phase transition (T(PU)) in isopropanol medium, and no such phase transition for methanol solution. In the mixed solvent (water + isopropanol) at 0-20% (v/v) isopropanol the TPL increases, whereas the T(PU) decreases at 92-100% with isopropanol content. For the mixture 20-90% isopropanol, PD particles having larger sizes (400-750 nm) exhibit neither any break in Z-average size-temperature plot nor any cloudiness, indicating their dispersed swelled state in the medium. In the methanol + water mixture with methanol content of 0-30%, T(PL) increases, and at 40-60% both UCST- and LCST-type phase separations occur simultaneously, but at 70-90% methanol the swelled state of the particles (size 250-375 nm) is noticed. For 50 vol % methanol by varying polymer concentration (0.07-0.2% w/v) we have drawn a quasibinary phase diagram that indicates an approximate inverted hourglass phase diagram where a swelled state exists between two single phase boundary produced from LCST- and UCST-type phase transitions. An attempt is made to understand the phase separation process by temperature-dependent (1)H NMR spectroscopy along with transmission electron microscopy. PMID:26859626

  16. Purification of vetiver alcohols and esters for quantitative high-performance thin-layer chromatography determination in Haitian vetiver essential oils and vetiver acetates.

    PubMed

    Paillat, Lionel; Périchet, Christine; Pierrat, Jean-Philippe; Lavoine, Sophie; Filippi, Jean-Jacques; Meierhenrich, Uwe; Fernandez, Xavier

    2012-06-01

    A simple, fast, and efficient High-Performance Thin-Layer Chromatography (HPTLC) method was developed for the simultaneous quantitative determination of alcohols and acetates in Haitian vetiver essential oils (Chryzopogon zizanioides) and its acetylated form. Analytes were separated by using a mixture of n-hexane-chloroform-ethyl acetate (8:6:0.5, v/v/v) as mobile phase under 47% humidity. Quantification was achieved by densitometric evaluation of the analytes in absorbance mode under visible light (λ=530 nm) after staining with a vanillin-sulfuric acid reagent. Reference mixtures of alcohols and acetates were obtained by fractionation of Haitian vetiver oil or vetiver acetates, followed by purification of the fractions of interest by means of Over-Pressured Layer Chromatography (OPLC). The chemical composition of each reference fraction was determined by using GC-MS and GC×GC-MS, and their overall purity was determined by GC/FID and HPTLC. The TLC method provided compact spots for alcohols (R(f2)=0.18±0.01 and R(f1)=0.28±0.01) and acetates (R(f3)=0.65±0.01). Calibration plots showed good linear correlation with r²=0.9995±0.0001 and r²=0.9995±0.0001 for alcohols and r²=0.9996±0.0001 for acetates in a 40-200 ng spot⁻¹ concentration range with respect to peak areas. The method was validated for precision and accuracy. Limit of detection (LOD) and quantification (LOQ) were determined. Method specificity was confirmed using retention factor (R(f)) and GC-MS control of the standards reference mixtures. PMID:22560705

  17. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    DOEpatents

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

    2016-03-15

    Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

  18. Methods of refining and producing dibasic esters and acids from natural oil feedstocks

    SciTech Connect

    Snead, Thomas E; Cohen, Steven A; Gildon, Demond L

    2015-04-07

    Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

  19. Metal ion complexation by ionizable crown ethers. Progress report, January 1, 1991--December 31, 1993

    SciTech Connect

    Bartsch, R.A.

    1993-07-01

    Cyclic and acyclic polyether compounds with pendent carboxylic acid, phosphonic acid monoethyl ester, sulfonic acid, phosphinic acid and hydroxamic acid groups have been synthesized. The proton-ionizable polyethers can come with and without lipophilic groups. Two types of lipophilic di-ionizable lariat ethers have been prepared. Conformations of proton-ionizable lariat ethers have been probed. Competitive alkali metal cation transport by syn-(decyl)dibenzo-16-crown-5-oxyacetic acid and lipophilic proton-ionizable dibenzo lariat ethers in polymer-supported liquid membranes was studied. Complexation of alkali metal cations with ionized lariat ethers was studied. Condensation polymerization of cyclic and acyclic dibenzo polyethers containing pendent mono-ionizable groups with formaldehyde produces novel ion exchange resins with both ion exchange sites for metal ion complexation and polyether binding sites for metal ion recognition. Resins prepared from lariat ether dibenzo phosphonic acid monoethyl esters show strong sorption of divalent heavy metal cations with selectivity for Pb{sup 2+}.

  20. Lipoate ester models for multi-functional lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven lipoate esters were synthesized by esterification of lipoic acid with different structures of alcohols in the presence of a solid acid catalyst and without solvent. The esters were obtained in good yield, characterized using 1H NMR and GPC; and their physical properties investigated. Four of t...

  1. Poly(arylene ether)s containing pendent ethynyl groups

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Jensen, Brian J. (Inventor)

    1996-01-01

    Poly(arylene ether)s containing pendent ethynyl and substituted ethynyl groups and poly(arylene ether) copolymers containing pendent ethynyl and substituted ethynyl groups are readily prepared from bisphenols containing ethynyl and substituted ethynyl groups. The resulting polymers are cured up to 350.degree. C. to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

  2. Design, synthesis, and biological activity of oxime ether strobilurin derivatives containing indole moiety as novel fungicide.

    PubMed

    Xie, Ya-Qiang; Huang, Zi-Long; Yan, Hui-Dong; Li, Jun; Ye, Li-Yi; Che, Li-Ming; Tu, Song

    2015-06-01

    Twenty-one novel oxime ether strobilurins containing indole moiety, which employed an indole group to stabilize the E-styryl group in Enoxastrobin, were designed and synthesized. The biological assay indicated that most compounds exhibited potent fungicidal activities. The structure-activity relationship study demonstrated that the synthesized methyl 3-methoxypropenoate oxime ethers 7b-e exhibited remarkably high activities among all the synthesized oxime ether compounds 7. Moreover, the fungicidal activities of methyl α-(methoxyimino)benzeneacetate oxime ethers compounds 7f-i and N-methoxy-carbamic acid methyl esters compounds 7j-m showed significant differences compared to the corresponding products of ammonolysis. PMID:25346294

  3. Derivatives of iminomalonic ester

    SciTech Connect

    Prosyanik, A.V.; Fedoseenko, D.V.; Markov, V.I.

    1986-01-10

    The synthesis of (alkylimino)malonic esters was realized by the reaction of alkylamines with mesoxalic or dibromomalonic ester. (Halogenoimino)malonic esters were obtained for the first time by the reaction of aminomalonic ester with tert-butyl hypochlorite or sodium hypobromite. A new method was developed for the synthesis of (acylimino)malonic esters by the successive bromination and dehydrobromination of (acylamino)malonic esters. The addition of various nucleophiles (water, amines, formamide) at the C=N bond of (acylimino)malonic esters was studied.

  4. Bio-based alternative to the diglycidyl ether of bisphenol A with controlled materials properties.

    PubMed

    Maiorana, Anthony; Spinella, Stephen; Gross, Richard A

    2015-03-01

    A series of biobased epoxy monomers were prepared from diphenolic acid (DPA) by transforming the free acid into n-alkyl esters and the phenolic hydroxyl groups into diglycidyl ethers. NMR experiments confirmed that the diglycidyl ethers of diphenolates (DGEDP) with methyl and ethyl esters have 6 and 3 mol % of glycidyl ester. Increasing the chain length of DGEDP n-alkyl esters from methyl to n-pentyl resulted in large decreases in epoxy resin viscosity (700-to-11 Pa·s). Storage modulus of DPA epoxy resins, cured with isophorone diamine, also varied with n-alkyl ester chain length (e.g., 3300 and 2100 MPa for the methyl and n-pentyl esters). The alpha transition temperature of the cured materials showed a linear decrease from 158 to 86 °C as the ester length increases. The Young's modulus and tensile strengths were about 1150 and 40 MPa, respectively, for all the cured resins tested (including DGEBA) and varied little as a function of ester length. Degree of cure for the different epoxy resins, determined by FTIR and DSC, closely approached the theoretical maximum. The result of this work demonstrates that diglycidyl ethers of n-alkyl diphenolates represent a new family of biobased liquid epoxy resins that, when cured, have similar properties to those from DGEBA. PMID:25633466

  5. Methods of refining and producing isomerized fatty acid esters and fatty acids from natural oil feedstocks

    DOEpatents

    Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.; Beltran, Leslie V.; Kunz, Linda A.; Pals, Tessa M.; Quinn, Jordan R; Behrends, Jr., Raymond T.; Bernhardt, Randal J.

    2016-07-05

    Methods are provided for refining natural oil feedstocks and producing isomerized esters and acids. The methods comprise providing a C4-C18 unsaturated fatty ester or acid, and isomerizing the fatty acid ester or acid in the presence of heat or an isomerization catalyst to form an isomerized fatty ester or acid. In some embodiments, the methods comprise forming a dibasic ester or dibasic acid prior to the isomerizing step. In certain embodiments, the methods further comprise hydrolyzing the dibasic ester to form a dibasic acid. In certain embodiments, the olefin is formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having unsaturated esters.

  6. Determination of Methyl tert-Butyl Ether and tert-Butyl Alcohol in Water by Solid-Phase Microextraction/Head Space Analysis in Comparison to EPA Method 5030/8260B

    SciTech Connect

    Oh, Keun-Chan; Stringfellow, William T.

    2003-10-02

    Methyl tert-butyl ether (MTBE) is now one of the most common groundwater contaminants in the United States. Groundwater contaminated with MTBE is also likely to be contaminated with tert-butyl alcohol (TBA), because TBA is a component of commercial grade MTBE, TBA can also be used as a fuel oxygenate, and TBA is a biodegradation product of MTBE. In California, MTBE is subject to reporting at concentrations greater than 3 {micro}g/L. TBA is classified as a ''contaminant of current interest'' and has a drinking water action level of 12 {micro}g/L. In this paper, we describe the development and optimization of a simple, automated solid phase microextraction (SPME) method for the analysis of MTBE and TBA in water and demonstrate the applicability of this method for monitoring MTBE and TBA contamination in groundwater, drinking water, and surface water. In this method, the headspace (HS) of a water sample is extracted with a carboxen/polydimethylsiloxane SPME fiber, the MTBE and TBA are desorbed into a gas chromatograph (GC), and detected using mass spectrometry (MS). The method is optimized for the routine analysis of MTBE and TBA with a level of quantitation of 0.3 {micro}g/L and 4 {micro}g/L, respectively, in water. MTBE quantitation was linear for over two orders of concentration (0.3 {micro}g/L -80 {micro}g/L). TBA was found to be linear within the range of 4 {micro}g/L-7,900 {micro}g/L. The lower level of detection for MTBE is 0.03 {micro}g/L using this method. This SPME method using headspace extraction was found to be advantageous over SPME methods requiring immersion of the fiber into the water samples, because it prolonged the life of the fiber by up to 400 sample analyses. This is the first time headspace extraction SPME has been shown to be applicable to the measurement of both MTBE and TBA at concentrations below regulatory action levels. This method was compared with the certified EPA Method 5030/8260B (purge-and-trap/GC/MS) using split samples from

  7. Additional Nucleophile-Free FeCl3-Catalyzed Green Deprotection of 2,4-Dimethoxyphenylmethyl-Protected Alcohols and Carboxylic Acids.

    PubMed

    Sawama, Yoshinari; Masuda, Masahiro; Honda, Akie; Yokoyama, Hiroki; Park, Kwihwan; Yasukawa, Naoki; Monguchi, Yasunari; Sajiki, Hironao

    2016-01-01

    The deprotection of the methoxyphenylmethyl (MPM) ether and ester derivatives can be generally achieved by the combinatorial use of a catalytic Lewis acid and stoichiometric nucleophile. The deprotections of 2,4-dimethoxyphenylmethyl (DMPM)-protected alcohols and carboxylic acids were found to be effectively catalyzed by iron(III) chloride without any additional nucleophile to form the deprotected mother alcohols and carboxylic acids in excellent yields. Since the present deprotection proceeds via the self-assembling mechanism of the 2,4-DMPM protective group itself to give the hardly-soluble resorcinarene derivative as a precipitate, the rigorous purification process by silica-gel column chromatography was unnecessary and the sufficiently-pure alcohols and carboxylic acids were easily obtained in satisfactory yields after simple filtration. PMID:27373632

  8. Crown ethers in graphene

    SciTech Connect

    Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; Gallego, Nidia C.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Moyer, Bruce A.; Chisholm, Matthew F.

    2014-11-13

    Crown ethers, introduced by Pedersen1, are at their most basic level neutral rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted special attention for their ability to selectively incorporate various atoms2 or molecules within the cavity formed by the ring3-6. This property has led to the use of crown ethers and their compounds in a wide range of chemical and biological applications7,8. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity9,10. In this Letter, we report atomic-resolution images of the same basic structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar and thus uniquely suited for the many applications that crown ethers are known for. First-principles calculations show that the close similarity of the structures seen in graphene with those of crown ether molecules also extends to their selectivity towards specific metal cations depending on the ring size. Atoms (or molecules) incorporated within the crown ethers in graphene offer a simple environment that can be easily and systematically probed and modeled. Thus, we expect that this discovery will introduce a new wave of investigations and applications of chemically functionalized graphene.

  9. Crown ethers in graphene

    DOE PAGESBeta

    Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; Gallego, Nidia C.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Moyer, Bruce A.; Chisholm, Matthew F.

    2014-11-13

    Crown ethers, introduced by Pedersen1, are at their most basic level neutral rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted special attention for their ability to selectively incorporate various atoms2 or molecules within the cavity formed by the ring3-6. This property has led to the use of crown ethers and their compounds in a wide range of chemical and biological applications7,8. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity9,10. In this Letter, we report atomic-resolution images of the same basicmore » structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar and thus uniquely suited for the many applications that crown ethers are known for. First-principles calculations show that the close similarity of the structures seen in graphene with those of crown ether molecules also extends to their selectivity towards specific metal cations depending on the ring size. Atoms (or molecules) incorporated within the crown ethers in graphene offer a simple environment that can be easily and systematically probed and modeled. Thus, we expect that this discovery will introduce a new wave of investigations and applications of chemically functionalized graphene.« less

  10. Crown ethers in graphene

    NASA Astrophysics Data System (ADS)

    Guo, Junjie; Lee, Jaekwang; Contescu, Cristian I.; Gallego, Nidia C.; Pantelides, Sokrates T.; Pennycook, Stephen J.; Moyer, Bruce A.; Chisholm, Matthew F.

    2014-11-01

    Crown ethers are at their most basic level rings constructed of oxygen atoms linked by two- or three-carbon chains. They have attracted attention for their ability to selectively incorporate various atoms or molecules within the cavity formed by the ring. However, crown ethers are typically highly flexible, frustrating efforts to rigidify them for many uses that demand higher binding affinity and selectivity. Here we present atomic-resolution images of the same basic structures of the original crown ethers embedded in graphene. This arrangement constrains the crown ethers to be rigid and planar. First-principles calculations show that the close similarity of the structures should also extend to their selectivity towards specific metal cations. Crown ethers in graphene offer a simple environment that can be systematically tested and modelled. Thus, we expect that our finding will introduce a new wave of investigations and applications of chemically functionalized graphene.

  11. Expanding the modular ester fermentative pathways for combinatorial biosynthesis of esters from volatile organic acids.

    PubMed

    Layton, Donovan S; Trinh, Cong T

    2016-08-01

    Volatile organic acids are byproducts of fermentative metabolism, for example, anaerobic digestion of lignocellulosic biomass or organic wastes, and are often times undesired inhibiting cell growth and reducing directed formation of the desired products. Here, we devised a general framework for upgrading these volatile organic acids to high-value esters that can be used as flavors, fragrances, solvents, and biofuels. This framework employs the acid-to-ester modules, consisting of an AAT (alcohol acyltransferase) plus ACT (acyl CoA transferase) submodule and an alcohol submodule, for co-fermentation of sugars and organic acids to acyl CoAs and alcohols to form a combinatorial library of esters. By assembling these modules with the engineered Escherichia coli modular chassis cell, we developed microbial manufacturing platforms to perform the following functions: (i) rapid in vivo screening of novel AATs for their catalytic activities; (ii) expanding combinatorial biosynthesis of unique fermentative esters; and (iii) upgrading volatile organic acids to esters using single or mixed cell cultures. To demonstrate this framework, we screened for a set of five unique and divergent AATs from multiple species, and were able to determine their novel activities as well as produce a library of 12 out of the 13 expected esters from co-fermentation of sugars and (C2-C6) volatile organic acids. We envision the developed framework to be valuable for in vivo characterization of a repertoire of not-well-characterized natural AATs, expanding the combinatorial biosynthesis of fermentative esters, and upgrading volatile organic acids to high-value esters. Biotechnol. Bioeng. 2016;113: 1764-1776. © 2016 Wiley Periodicals, Inc. PMID:26853081

  12. Bacterial Utilization of Ether Glycols

    PubMed Central

    Fincher, Edward L.; Payne, W. J.

    1962-01-01

    A soil bacterium capable of using oligo- and polyethylene glycols and ether alcohols as sole sources of carbon for aerobic growth was isolated. The effects of substituent groups added to the ether bonds on the acceptability of the compounds as substrates were studied. Mechanisms for the incorporation of two-carbon compounds were demonstrated by the observation that acetate, glyoxylate, ethylene glycol, and a number of the tricarboxylic acid cycle intermediates served as growth substrates in minimal media. The rate of oxidation of the short-chained ethylene glycols by adapted resting cells varied directly with increasing numbers of two-carbon units in the chains from one to four. The amount of oxygen consumed per carbon atom of oligo- and polyethylene glycols was 100% of theoretical, but only 67% of theoretical for ethylene glycol. Resting cells oxidized oligo- and polyethylene glycols with 2 to 600 two-carbon units in the chains. Longer chained polyethylene glycols (up to 6,000) were oxidized at a very slow rate by these cells. Dehydrogenation of triethylene glycol by adapted cells was observed, coupling the reaction with methylene blue reduction. PMID:13945208

  13. Interactions between ether phospholipids and cholesterol as determined by scattering and molecular dynamics simulations.

    PubMed

    Pan, Jianjun; Cheng, Xiaolin; Heberle, Frederick A; Mostofian, Barmak; Kučerka, Norbert; Drazba, Paul; Katsaras, John

    2012-12-27

    Cholesterol and ether lipids are ubiquitous in mammalian cell membranes, and their interactions are crucial in ether lipid mediated cholesterol trafficking. We report on cholesterol's molecular interactions with ether lipids as determined using a combination of small-angle neutron and X-ray scattering, and all-atom molecular dynamics (MD) simulations. A scattering density profile model for an ether lipid bilayer was developed using MD simulations, which was then used to simultaneously fit the different experimental scattering data. From analysis of the data the various bilayer structural parameters were obtained. Surface area constrained MD simulations were also performed to reproduce the experimental data. This iterative analysis approach resulted in good agreement between the experimental and simulated form factors. The molecular interactions taking place between cholesterol and ether lipids were then determined from the validated MD simulations. We found that in ether membranes cholesterol primarily hydrogen bonds with the lipid headgroup phosphate oxygen, while in their ester membrane counterparts cholesterol hydrogen bonds with the backbone ester carbonyls. This different mode of interaction between ether lipids and cholesterol induces cholesterol to reside closer to the bilayer surface, dehydrating the headgroup's phosphate moiety. Moreover, the three-dimensional lipid chain spatial density distribution around cholesterol indicates anisotropic chain packing, causing cholesterol to tilt. These insights lend a better understanding of ether lipid-mediated cholesterol trafficking and the roles that the different lipid species have in determining the structural and dynamical properties of membrane associated biomolecules. PMID:23199292

  14. Interactions between Ether Phospholipids and Cholesterol as Determined by Scattering and Molecular Dynamics Simulations

    SciTech Connect

    Pan, Jianjun; Cheng, Xiaolin; Heberle, Frederick A; Mostofian, Barmak; Kucerka, Norbert; Drazba, Paul; Katsaras, John

    2012-01-01

    Cholesterol and ether lipids are ubiquitous in mammalian cell membranes, and their interactions are crucial in ether lipid mediated cholesterol trafficking. We report on cholesterol s molecular interactions with ether lipids as determined using a combination of small-angle neutron and Xray scattering, and all-atom molecular dynamics (MD) simulations. A scattering density profile model for an ether lipid bilayer was developed using MD simulations, which was then used to simultaneously fit the different experimental scattering data. From analysis of the data the various bilayer structural parameters were obtained. Surface area constrained MD simulations were also performed to reproduce the experimental data. This iterative analysis approach resulted in good agreement between the experimental and simulated form factors. The molecular interactions taking place between cholesterol and ether lipids were then determined from the validated MD simulations. We found that in ether membranes cholesterol primarily hydrogen bonds with the lipid headgroup phosphate oxygen, while in their ester membrane counterparts cholesterol hydrogen bonds with the backbone ester carbonyls. This different mode of interaction between ether lipids and cholesterol induces cholesterol to reside closer to the bilayer surface, dehydrating the headgroup s phosphate moiety. Moreover, the three-dimensional lipid chain spatial density distribution around cholesterol indicates anisotropic chain packing, causing cholesterol to tilt. These insights lend a better understanding of ether lipid-mediated cholesterol trafficking and the roles that the different lipid species have in determining the structural and dynamical properties of membrane associated biomolecules.

  15. INTRAVENOUS ETHER ANESTHESIA

    PubMed Central

    Eger, Edmond I.; Johnson, Edward A.

    1963-01-01

    From a study of intravenous ether anesthesia, it was concluded that ether diluted to a 5 per cent solution in 5 per cent dextrose and water may be used to induce and maintain a smooth and easily controlled anesthetic state similar to that obtained with inhalation ether but without the dependence of the latter technique on ventilation. Cough and laryngospasm were absent. Adequate spontaneous respiration can be maintained with this technique. The technique is particularly useful in endoscopy during which the airway is often not available for anesthetic administration. PMID:14051486

  16. Vinyl ether silicones

    SciTech Connect

    Herzig, C.; Dauth, J.; Deubzer, B.; Weis, J.

    1995-12-01

    Siloxanes with vinyl ether groups are prepared by hydrosilylation reaction of dihydrosiloxanes with divinyl ethers in excess. Different stoichiometry, produces linear copolymers of different viscosities and double bond concentrations always with an active vinyl ether group at each chain end. Polymerisations triggered by UV light were done with mixtures of these compounds and a series of onium salts. Very fast cure is observed even with low doses at 290 nm. V.E. silicones are found to cure essentially quantitative. The comparison with other highly reactive cationic monomers revealed that compounds are among the fastest curing prepolymers in cationic chemistry.

  17. Genotoxicity of glycol ethers.

    PubMed Central

    McGregor, D B

    1984-01-01

    The genetic toxicology of glycol ethers is reviewed. Ethylene glycol monomethyl ether (EGME) and diglyme have been more extensively studied than other members of this series. Most results indicate a lack of genotoxic potential, but certain tests have yielded positive responses with certain compounds. Ethylene glycol monoethyl ether (EGEE) induced sister chromatid exchanges and chromosomal aberrations in cultured cells. Both EGME and diglyme induced mouse sperm head morphological changes, male rat weak dominant lethal mutations and marked, but reversible, loss of male rat fertility. PMID:6541999

  18. Catalytic oxidation of dimethyl ether

    DOEpatents

    Zelenay, Piotr; Wu, Gang; Johnston, Christina M.; Li, Qing

    2016-05-10

    A composition for oxidizing dimethyl ether includes an alloy supported on carbon, the alloy being of platinum, ruthenium, and palladium. A process for oxidizing dimethyl ether involves exposing dimethyl ether to a carbon-supported alloy of platinum, ruthenium, and palladium under conditions sufficient to electrochemically oxidize the dimethyl ether.

  19. Alcoholism and Alcohol Abuse

    MedlinePlus

    ... This means that their drinking causes distress and harm. It includes alcoholism and alcohol abuse. Alcoholism, or ... brain, and other organs. Drinking during pregnancy can harm your baby. Alcohol also increases the risk of ...

  20. MEASUREMENT OF EXHALED BREATH AND VENOUS BLOOD TO DEVELOP A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURE TO METHYL TERTIARY-BUTYL ETHER AND THE PRODUCTION OF THE BIOMARKER TERTIARY-BUTYL ALCOHOL

    EPA Science Inventory

    Methyl tertiary-butyl ether (MTBE) is a common fuel additive used to increase the availability of oxygen in gasoline to reduce winter-time carbon monoxide emissions from automobiles. Also, MTBE boosts gasoline "octane" rating and, as such, allows reduction of benzene...

  1. Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters.

    PubMed

    Li, Yuehui; Topf, Christoph; Cui, Xinjiang; Junge, Kathrin; Beller, Matthias

    2015-04-20

    Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. PMID:25728921

  2. Phthalate esters as peroxisome proliferator carcinogens.

    PubMed Central

    Warren, J R; Lalwani, N D; Reddy, J K

    1982-01-01

    The phthalate ester di(2-ethylhexyl) phthalate is both a peroxisome proliferator and a hepatic carcinogen. Peroxisome proliferators as a class are hepatocarcinogenic in rodent species. However, none of the peroxisome proliferators tested to date including the phthalate esters and related alcohol and acid analogs have demonstrated mutagenic or DNA-damaging activity in the in vitro Salmonella typhimurium/microsomal or the lymphocyte 3H-thymidine assays. A working hypothesis is proposed that peroxisome proliferation itself initiates neoplastic transformation of hepatic parenchymal cells by increasing intracellular rates of DNA-damaging reactive oxygen production. Evidence which supports such a hypothesis includes increased fatty acid beta-oxidation, elevated H2O2 levels, accumulation of peroxidized lipofuscin, disproportionately small increase in catalase, and elevated peroxisomal uricase activity which accompany peroxisome proliferation in hepatocytes. Direct testing of this hypothesis will provide insight into mechanisms of phthalate ester carcinogenicity and cytotoxicity. Images FIGURE 1. PMID:6754363

  3. CONVERSION OF DIMETHYL ETHER-BORON TRIFLUORIDE COMPLEX TO POTASSIUM FLUOBORATE

    DOEpatents

    Eberle, A.R.

    1957-06-18

    A method of preparing KBF/sub 4/ from the dimethyl ether complex of BF/sub 3/ is given. This may be accomplished by introducing the dimethyl ether complex of BF/sub 3/ into an aqueous solution of KF and alcohol, expelling the ether liberated from the complex by heating or stirring and recovering the KBF/sub 4/ so formed. The KBF/sub 4/ is then filtered from the alcohol-water solution, which may be recycled, to reduce the loss of KBF/sub 4/ which is not recovered by filtration.

  4. Conversion of dimethyl ether--boron trifluoride complex to potassium fluoborate

    DOEpatents

    Eberle, A.R.

    1957-06-18

    A method of preparing KBF/sub 4/ from the dimethyl ether complex of BF/sub 3/ is given. This may be accomplished by introducing the dimethyl ether complex of BF/sub 3/ into an aqueous solution of KF and alcohol, expelling the ether liberated from the complex by heating or stirring and recovering the KBF/sub 4/ so formed. The KBF/sub 4/ is then filtered from the alcohol-water solution, which may be recycled, to reduce the loss of KBF/sub 4/ which is not recovered by filtration.

  5. Discrimination against diacylglycerol ethers in lipase-catalysed ethanolysis of shark liver oil.

    PubMed

    Fernández, Óscar; Vázquez, Luis; Reglero, Guillermo; Torres, Carlos F

    2013-01-15

    Lipase-catalysed ethanolysis of squalene-free shark liver oil was investigated. The mentioned shark liver oil was comprised mainly of diacylglycerol ether and triacylglycerols. In order to test discrimination against diacylglycerol ether, up to 10 different lipases were compared. The ratio of oil to ethanol and lipase stability were also evaluated. Surprisingly, lipase from Pseudomonas stutzeri was the fastest biocatalyst among all assayed, although poor discrimination against diacylglycerol ether was observed. The best results in terms of selectivity and stability were obtained with immobilised lipase from Candida antarctica (Novozym 435). Ethanolysis reaction after 24h in the presence of Novozym 435 produced total disappearance of triacylglycerol and a final reaction mixture comprised mainly of diacylglycerol ethers (10.6%), monoacylglycerol ethers (32.9%) and fatty acid ethyl esters (46.0%). In addition, when an excess of ethanol was used, diacylglycerol ethers completely disappeared after 15 h, giving a final product mainly composed of monoacylglycerol ethers (36.6%) and fatty acid ethyl esters (46.4%). PMID:23122085

  6. History of arsenic ethers: who was Felix D'Arcet?

    PubMed

    Petroianu, G A

    2012-11-01

    Williamson serendipitously discovered (1851) a new and efficient way to produce esters using ethyl iodide and potassium salts and in doing so elucidated the molecular mechanism behind ether formation. Lassaigne (1820) made the analogy between sulphovinic and phosphovinic acids and demonstrated the existence of phosphovinic acid, while Pelouze (1833) synthesised monoethyl phosphovinic acid. Finally 1848 Voegeli produced diethyl phosphovinic acid and the first neutral ester of phosphoric acid, the triethyl phosphate (TEP). The successes of Lassaigne and Pelouze in producing phosphovinic acids and Mitscherlich's theory of isomorphism fuelled the search for the vinic acids of arsenic, phosphorus neighbor in the periodic system. This short report attempts to identify the (less known) pharmacists and chemists involved in the quest for both arsenovinic acids and the neutral esters of arsenic and pyroarsenic acids. PMID:23210247

  7. Comparative inhalation teratogenicity of four glycol ether solvents and an amino derivative in rats.

    PubMed Central

    Nelson, B K; Setzer, J V; Brightwell, W S; Mathinos, P R; Kuczuk, M H; Weaver, T E; Goad, P T

    1984-01-01

    Previous research demonstrated the inhalation teratogenicity of the solvent 2-ethoxyethanol in rats and rabbits. As this is one of a class of widely used industrial solvents, we investigated the teratogenicity of five structurally related compounds. Each chemical was vaporized and administered to approximately 15 pregnant rats in one to three concentrations for 7 hr/day on gestation days 7 to 15, and dams were sacrificed on day 20. Fetuses were individually weighed, and two-thirds of them were fixed in Bouin's solution and examined for soft-tissue anomalies. The other one-third were fixed in alcohol, stained with Alizarin Red and examined for skeletal defects. Data were analyzed on a litter basis; three solvents were compared with a pooled group (N = 34) of sham-exposed controls, and the remaining two were compared with a group of 15 controls. At concentrations which were apparently not maternally toxic, 2-methoxyethanol was highly embryotoxic, producing complete resorptions at 200 ppm; increased resorptions, reduced fetal weights and skeletal and cardiovascular defects occurred at both 100 and 50 ppm. 2-ethoxyethyl acetate at 600 ppm induced complete resorption of litters; 390 ppm reduced fetal weights and induced skeletal and cardiovascular defects, but only a single defect was observed at 130 ppm. 2-Butoxyethanol evidenced slight maternal toxicity at 200 ppm but produced no increase in congenital defects at that concentration. Neither 2-(2-ethoxyethoxy)ethanol (100 ppm) nor 2-methylaminoethanol (150 ppm) was maternally toxic or embryotoxic. In summary, shorter alkyl chained glycol ethers produced greater embryotoxicity than those having longer chains, and the ester produced effects equivalent to the ether, both patterns predictable from the biochemical literature. PMID:6499812

  8. Synthesis of bioreductive esters from fungal compounds.

    PubMed

    Weerapreeyakul, Natthida; Anorach, Rutchayaporn; Khuansawad, Thidarut; Yenjai, Chavi; Isaka, Masahiko

    2007-06-01

    Four new bioreductive esters (7-10) have been synthesized. Their structures composed of trimethyl lock containing quinone propionic acid with an ester linkage to the fungal cytotoxic compounds; preussomerin G (1), preussomerin I (2), phaseolinone (3) and phomenone (4). The synthesized esters are aimed to act via reductive activation specifically at the cancer cells, resulting from hypoxia and overexpression of reductases. Hence, the toxicity will be lessened during distribution across the normal cells. The anticancer activity was determined in cancer cell lines with reported reductase i.e., BC-1 cells and NCI-H187 as well as in non-reductase containing cancer cells; KB cells. When considering each cell lines, result showed that structure modification giving to 7-10 led to less cytotoxicity than their parent compounds (1-4). Both 7 and 8 were strongly cytotoxic (IC50 < or = 5 microg/ml) to NCI-H187, whereas 9 and 10 were moderately cytotoxic (IC50 = 6-10 microg/ml) to BC-1 cells. Additional study of stability of represented phenolic ester (8) and an alcoholic ester (9) were performed. Result illustrated that both 8 and 9 were stable in the presence of esterase. Therefore, the cytotoxicity of the synthesized compounds (8-10) might be due to partial bioreductive activation in the cancer cells. PMID:17541198

  9. Oxydifluoromethylation of Alkenes by Photoredox Catalysis: Simple Synthesis of CF2H-Containing Alcohols.

    PubMed

    Arai, Yusuke; Tomita, Ren; Ando, Gaku; Koike, Takashi; Akita, Munetaka

    2016-01-22

    We have developed a novel and simple protocol for the direct incorporation of a difluoromethyl (CF2 H) group into alkenes by visible-light-driven photoredox catalysis. The use of fac-[Ir(ppy)3] (ppy=2-pyridylphenyl) photocatalyst and shelf-stable Hu's reagent, N-tosyl-S-difluoromethyl-S-phenylsulfoximine, as a CF2 H source is the key to success. The well-designed photoredox system achieves synthesis of not only β-CF2 H-substituted alcohols but also ethers and an ester from alkenes through solvolytic processes. The present method allows a single-step and regioselective formation of C(sp(3))-CF2 H and C(sp(3))-O bonds from C=C moiety in alkenes, such as hydroxydifluoromethylation, regardless of terminal or internal alkenes. Moreover, this methodology tolerates a variety of functional groups. PMID:26639021

  10. Oxydifluoromethylation of Alkenes by Photoredox Catalysis: Simple Synthesis of CF2H‐Containing Alcohols

    PubMed Central

    Arai, Yusuke; Tomita, Ren; Ando, Gaku

    2015-01-01

    Abstract We have developed a novel and simple protocol for the direct incorporation of a difluoromethyl (CF2H) group into alkenes by visible‐light‐driven photoredox catalysis. The use of fac‐[Ir(ppy)3] (ppy=2‐pyridylphenyl) photocatalyst and shelf‐stable Hu's reagent, N‐tosyl‐S‐difluoromethyl‐S‐phenylsulfoximine, as a CF2H source is the key to success. The well‐designed photoredox system achieves synthesis of not only β‐CF2H‐substituted alcohols but also ethers and an ester from alkenes through solvolytic processes. The present method allows a single‐step and regioselective formation of C(sp3)–CF2H and C(sp3)−O bonds from C=C moiety in alkenes, such as hydroxydifluoromethylation, regardless of terminal or internal alkenes. Moreover, this methodology tolerates a variety of functional groups. PMID:26639021

  11. A new multifunctional, shine-enhancing emollient: PPG-3 benzyl ether myristate.

    PubMed

    Gao, Timothy; Pereira, Abel; Obukowho, Patrick

    2004-01-01

    A new emollient ester--Crodamol STS (INCI name: PPG-3 Benzyl Ether Myristate) has been developed and characterized. This special non-volatile emollient is safe to use and provides silicone-like feel and multiple cosmetic functionality. It is a liquid with a viscosity about 100 cps at room temperature. It has a high refractive index--1.4696, which enhances hair shine, contributes to high gloss in lip products, and reduces whitening effect of fatty alcohols and silica in anti-perspirants/deodorants applications. This emollient has high solubility of UV filters, low skin-spreading factor, and good pigment wetting behavior, which are preferable in sunscreen and make-up formulas to enhance the pigment localization and improve SPF value. In this paper, the chemical structure, physical properties, and various cosmetic applications of the emollient will be discussed. Especially, an objective hair shine (luster) test method (color image analysis) has been established and applied to study the enhancement in hair shine by Crodamol STS in hair spray and hair gel formulations. The objective measurements in hair shine showed good agreement with the results obtained from subjective evaluations. The substantivity of Crodamol STS on hair surface, which was delivered from a rinse-off cream, was also determined by a solvent extraction method. PMID:15645090

  12. Thermodynamics of Hydrogen Production from Dimethyl Ether Steam Reforming and Hydrolysis

    SciTech Connect

    T.A. Semelsberger

    2004-10-01

    The thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the process of dimethyl ether (DME) steam reforming were investigated as a function of steam-to-carbon ratio (0-4), temperature (100 C-600 C), pressure (1-5 atm), and product species: acetylene, ethanol, methanol, ethylene, methyl-ethyl ether, formaldehyde, formic acid, acetone, n-propanol, ethane and isopropyl alcohol. Results of the thermodynamic processing of dimethyl ether with steam indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure was observed to shift the equilibrium toward the reactants; increasing the pressure from 1 atm to 5 atm decreased the conversion of dimethyl ether from 99.5% to 76.2%. The order of thermodynamically stable products in decreasing mole fraction was methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol--formaldehyde, formic acid, and acetylene were not observed. The optimal processing conditions for dimethyl ether steam reforming occurred at a steam-to-carbon ratio of 1.5, a pressure of 1 atm, and a temperature of 200 C. Modeling the thermodynamics of dimethyl ether hydrolysis (with methanol as the only product considered), the equilibrium conversion of dimethyl ether is limited. The equilibrium conversion was observed to increase with temperature and steam-to-carbon ratio, resulting in a maximum dimethyl ether conversion of approximately 68% at a steam-to-carbon ratio of 4.5 and a processing temperature of 600 C. Thermodynamically, dimethyl ether processed with steam can produce hydrogen-rich fuel-cell feeds--with hydrogen concentrations exceeding 70%. This substantiates dimethyl ether as a viable source of hydrogen for PEM fuel cells.

  13. Triethylene glycol monoethyl ether

    Integrated Risk Information System (IRIS)

    Triethylene glycol monoethyl ether ; CASRN 112 - 50 - 5 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

  14. Triethylene glycol monobutyl ether

    Integrated Risk Information System (IRIS)

    Triethylene glycol monobutyl ether ; CASRN 143 - 22 - 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 fo

  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. p-Bromodiphenyl ether

    Integrated Risk Information System (IRIS)

    p - Bromodiphenyl ether ; CASRN 101 - 55 - 3 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 Noncarcin

  17. Chloromethyl methyl ether (CMME)

    Integrated Risk Information System (IRIS)

    Chloromethyl methyl ether ( CMME ) ; CASRN 107 - 30 - 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 Assessments fo

  18. Synthesis of 1-octanol and 1,1-dioctyl ether from biomass-derived platform chemicals.

    PubMed

    Julis, Jennifer; Leitner, Walter

    2012-08-20

    The happy medium: A new catalytic pathway for the synthesis of the linear primary C(8) alcohol products 1-octanol and dioctyl ether from furfural and acetone has been developed using retrosynthetic analysis. This opens a general strategy for the synthesis of medium-chain-length alcohols from carbohydrate feedstock. PMID:22778056

  19. Unprecedented reactions: from epichlorohydrin to epoxyglycidyl substituted divinyl ether and its conversion into epoxyglycidyl propargyl ether

    PubMed Central

    Yao, Yiwu; Li, Zheng; Qiu, Yatao; Bai, Jinhong; Su, Jinyue; Zhang, Dayong; Jiang, Sheng

    2015-01-01

    The reaction of epichlorohydrin with concentrated sodium hydroxide in hexane under phase transfer conditions has surprisingly led to the formation of the symmetrical di(3-epoxyglycidyl-1-propenyl) ether 1 which contains both nucleophilic and electrophilic moieties. When it was reacted with n-butyllithium, intermediate 1 once again surprisingly generated epoxyglycidyl propargyl ether, which was further reacted in situ with a variety of benzaldehydes to furnish the corresponding substituted propargylic alcohols in good yields. While the reaction is operationally simple, it provides a powerful method for the synthesis of the important products from commodity materials such as epichlorohydrin. Moreover, these reactions may have revealed that some fundamental properties of the hydroxide anion in those once thought straightforward reactions are not well understood. A careful analysis of the experimental data suggests that an unprecedented concerted elimination of the epoxyglycidyl ether with sodium hydroxide may be operative and an alpha deprotonation followed by alpha elimination of the di(3-epoxyglycidyl-1-propenyl) ether with alkyllithium may have been involved. PMID:26383123

  20. Unprecedented reactions: from epichlorohydrin to epoxyglycidyl substituted divinyl ether and its conversion into epoxyglycidyl propargyl ether

    NASA Astrophysics Data System (ADS)

    Yao, Yiwu; Li, Zheng; Qiu, Yatao; Bai, Jinhong; Su, Jinyue; Zhang, Dayong; Jiang, Sheng

    2015-09-01

    The reaction of epichlorohydrin with concentrated sodium hydroxide in hexane under phase transfer conditions has surprisingly led to the formation of the symmetrical di(3-epoxyglycidyl-1-propenyl) ether 1 which contains both nucleophilic and electrophilic moieties. When it was reacted with n-butyllithium, intermediate 1 once again surprisingly generated epoxyglycidyl propargyl ether, which was further reacted in situ with a variety of benzaldehydes to furnish the corresponding substituted propargylic alcohols in good yields. While the reaction is operationally simple, it provides a powerful method for the synthesis of the important products from commodity materials such as epichlorohydrin. Moreover, these reactions may have revealed that some fundamental properties of the hydroxide anion in those once thought straightforward reactions are not well understood. A careful analysis of the experimental data suggests that an unprecedented concerted elimination of the epoxyglycidyl ether with sodium hydroxide may be operative and an alpha deprotonation followed by alpha elimination of the di(3-epoxyglycidyl-1-propenyl) ether with alkyllithium may have been involved.

  1. Occurrence and Sources of Triterpenoid Methyl Ethers and Acetates in Sediments of the Cross-River System, Southeast Nigeria

    PubMed Central

    Oyo-Ita, Orok E.; Ekpo, Bassey O.; Oros, Daniel R.; Simoneit, Bernd R. T.

    2010-01-01

    Pentacyclic triterpenol methyl ethers (PTMEs), germanicol methyl ether (miliacin), 3-methoxyfern-9(11)-ene (arundoin), β-amyrin methyl ether (iso-sawamilletin), and 3-methoxytaraxer-14-ene (sawamilletin or crusgallin) were characterized in surface sediments of the Cross-River system using gas chromatography-mass spectrometry (GC-MS). Triterpenol esters (mainly α- and β-amyrinyl acetates and hexanoates, and lupeyl acetate and hexanoate) were also found. These distinct compounds are useful for assessing diagenesis that can occur during river transport of organic detritus. Poaceae, mainly Gramineae and Elaeis guineensis higher plant species, are proposed as primary sources for the PTMEs and esters in the sediments. PTMEs are biomarkers of specific higher plant subspecies, while the triterpenol esters are indicators of early diagenetic alteration of higher plant detritus. PMID:20414350

  2. Process for the synthesis of unsaturated alcohols

    DOEpatents

    Maughon, Bob R.; Burdett, Kenneth A.; Lysenko, Zenon

    2007-02-13

    A process of preparing an unsaturated alcohol (olefin alcohol), such as, a homo-allylic mono-alcohol or homo-allylic polyol, involving protecting a hydroxy-substituted unsaturated fatty acid or fatty acid ester, such as methyl ricinoleate, derived from a seed oil, to form a hydroxy-protected unsaturated fatty acid or fatty acid ester; homo-metathesizing or cross-metathesizing the hydroxy-protected unsaturated fatty acid or fatty acid ester to produce a product mixture containing a hydroxy-protected unsaturated metathesis product; and deprotecting the hydroxy-protected unsaturated metathesis product under conditions sufficient to prepare the unsaturated alcohol. Preferably, methyl ricinoleate is converted by cross-metathesis or homo-metathesis into the homo-allylic mono-alcohol 1-decene-4-ol or the homo-allylic polyol 9-octadecene-7,12-diol, respectively.

  3. Biosynthesis of archaeal membrane ether lipids

    PubMed Central

    Jain, Samta; Caforio, Antonella; Driessen, Arnold J. M.

    2014-01-01

    A vital function of the cell membrane in all living organism is to maintain the membrane permeability barrier and fluidity. The composition of the phospholipid bilayer is distinct in archaea when compared to bacteria and eukarya. In archaea, isoprenoid hydrocarbon side chains are linked via an ether bond to the sn-glycerol-1-phosphate backbone. In bacteria and eukarya on the other hand, fatty acid side chains are linked via an ester bond to the sn-glycerol-3-phosphate backbone. The polar head groups are globally shared in the three domains of life. The unique membrane lipids of archaea have been implicated not only in the survival and adaptation of the organisms to extreme environments but also to form the basis of the membrane composition of the last universal common ancestor (LUCA). In nature, a diverse range of archaeal lipids is found, the most common are the diether (or archaeol) and the tetraether (or caldarchaeol) lipids that form a monolayer. Variations in chain length, cyclization and other modifications lead to diversification of these lipids. The biosynthesis of these lipids is not yet well understood however progress in the last decade has led to a comprehensive understanding of the biosynthesis of archaeol. This review describes the current knowledge of the biosynthetic pathway of archaeal ether lipids; insights on the stability and robustness of archaeal lipid membranes; and evolutionary aspects of the lipid divide and the LUCA. It examines recent advances made in the field of pathway reconstruction in bacteria. PMID:25505460

  4. Process for producing high purity isoolefins and dimers thereof by dissociation of ethers

    DOEpatents

    Smith, Jr., Lawrence A.; Jones, Jr., Edward M.; Hearn, Dennis

    1984-01-01

    Alkyl tertiary butyl ether or alkyl tertiary amyl ether is dissociated by vapor phase contact with a cation acidic exchange resin at temperatures in the range of 150.degree. to 250.degree. F. at LHSV of 0.1 to 20 to produce a stream consisting of unreacted ether, isobutene or isoamylene and an alcohol corresponding to the alkyl radical. After the alcohol is removed, the ether/isoolefin stream may be fractionated to obtain a high purity isoolefin (99+%) or the ether/isoolefin stream can be contacted in liquid phase with a cation acidic exchange resin to selectively dimerize the isoolefin in a highly exothermic reaction, followed by fractionation of the dimerization product to produce high purity diisoolefin (97+%). In the case where the alkyl is C.sub.3 to C.sub.6 and the corresponding alcohol is produced on dissociation of the ether, combined dissociation-distillation may be carried out such that isoolefin is the overhead product and alcohol the bottom.

  5. Process for producing high purity isoolefins and dimers thereof by dissociation of ethers

    DOEpatents

    Smith, L.A. Jr.; Jones, E.M. Jr.; Hearn, D.

    1984-05-08

    Alkyl tertiary butyl ether or alkyl tertiary amyl ether is dissociated by vapor phase contact with a cation acidic exchange resin at temperatures in the range of 150 to 250 F at LHSV of 0.1 to 20 to produce a stream consisting of unreacted ether, isobutene or isoamylene and an alcohol corresponding to the alkyl radical. After the alcohol is removed, the ether/isoolefin stream may be fractionated to obtain a high purity isoolefin (99+%) or the ether/isoolefin stream can be contacted in liquid phase with a cation acidic exchange resin to selectively dimerize the isoolefin in a highly exothermic reaction, followed by fractionation of the dimerization product to produce high purity diisoolefin (97+%). In the case where the alkyl is C[sub 3] to C[sub 6] and the corresponding alcohol is produced on dissociation of the ether, combined dissociation-distillation may be carried out such that isoolefin is the overhead product and alcohol the bottom. 2 figs.

  6. Palladium-Catalyzed Benzylic Arylation of Pyridylmethyl Silyl Ethers: One-Pot Synthesis of Aryl(pyridyl)methanols.

    PubMed

    Rivero, Alexandra R; Kim, Byeong-Seon; Walsh, Patrick J

    2016-04-01

    An efficient palladium-catalyzed direct arylation of pyridylmethyl silyl ethers with aryl bromides is described. A Pd(OAc)2/NIXANTPHOS-based catalyst provides aryl(pyridyl)methyl alcohol derivatives in good to excellent yields (33 examples, 57-100% yield). This protocol is compatible with different silyl ether protecting groups, affording either the protected or the free alcohols in an effective one-pot process. The scalability of the reaction is demonstrated. PMID:27004592

  7. Comparison of surface modification of poly(ether urethanes) on physical properties and blood compatibility

    SciTech Connect

    Wrobleski, D.A.; Cash, D.L.; Hermes, R.E.

    1988-01-01

    Because of their good elastomeric properties including the ability to undergo repeated flexing without failure, polyurethanes are used in a number of biomedical applications including flexing diaphragms or coatings on surfaces in artificial hearts and heart assist devices. In particular, the poly(ether urethanes), are preferred for use in biomedical applications because of their greater hydrolytic stability as compared to poly(ester urethanes). However, poly(ether urethanes), as other polymeric materials in contact with blood, cause formation of thrombus and bacterial infections. These problems might be overcome by incorporation of antithrombogenic substances and/or antibacterial agents in the surface of the polymer. We have explored both of these methods by examining the infusion of polyvinylpyrrolidone (PVP) and poly(ethylene glycol) (PEG) into commercially available poly(ether urethanes) and the graft polymerization of N-vinyl pyrrolidone onto poly(ether urethanes). Preliminary results are presented here. 7 refs., 1 fig.

  8. Alcohol Alert

    MedlinePlus

    ... main content National Institute on Alcohol Abuse and Alcoholism (NIAAA) Main Menu Search Search form Search Alcohol & ... on a single aspect of alcohol abuse and alcoholism. Please click on the desired publication for full ...

  9. Mode of Action Studies on Nitrodiphenyl Ether Herbicides

    PubMed Central

    Bowyer, John R.; Smith, Beverly J.; Camilleri, Patrick; Lee, Susan A.

    1987-01-01

    5-[2-Chloro-4-(trifluoromethyl)phenoxy]-2-nitroacetophenone oxime-o-(acetic acid, methyl ester) (DPEI), is a potent nitrodiphenyl ether herbicide which causes rapid leaf wilting, membrane lipid peroxidation, and chlorophyll destruction in a process which is both light- and O2-dependent. These effects resemble those of other nitrodiphenyl ether herbicides. Unlike paraquat, the herbicidal effects of DPEI are only slightly reduced by pretreatment with the photosynthetic electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. DPEI is a weak inhibitor of photosynthetic electron transport (I50 15 micromolar for water to paraquat) in vitro, with at least one site of action at the cytochrome b6f complex. Ultrastructural studies and measurements of ethane formation resulting from lipid peroxidation indicate that mutants of barley lacking photosystem I (PSI) (viridis-zb63) or photosystem II (viridis-zd69) are resistant to paraquat but susceptible to DPEI. The results indicate that electron transfer through both photosystems is not essential for the toxic effects of nitrodiphenyl ether herbicides. Furthermore, the results show that neither cyclic electron transport around PSI, nor the diversion of electrons from PSI to O2 when NADPH consumption is blocked are essential for the phytotoxicity of nitrodiphenyl ether herbicides. Images Fig. 2 Fig. 3 Fig. 4 PMID:16665297

  10. Wax ester profiling of seed oil by nano-electrospray ionization tandem mass spectrometry

    PubMed Central

    2013-01-01

    Background Wax esters are highly hydrophobic neutral lipids that are major constituents of the cutin and suberin layer. Moreover they have favorable properties as a commodity for industrial applications. Through transgenic expression of wax ester biosynthetic genes in oilseed crops, it is possible to achieve high level accumulation of defined wax ester compositions within the seed oil to provide a sustainable source for such high value lipids. The fatty alcohol moiety of the wax esters is formed from plant-endogenous acyl-CoAs by the action of fatty acyl reductases (FAR). In a second step the fatty alcohol is condensed with acyl-CoA by a wax synthase (WS) to form a wax ester. In order to evaluate the specificity of wax ester biosynthesis, analytical methods are needed that provide detailed wax ester profiles from complex lipid extracts. Results We present a direct infusion ESI-tandem MS method that allows the semi-quantitative determination of wax ester compositions from complex lipid mixtures covering 784 even chain molecular species. The definition of calibration prototype groups that combine wax esters according to their fragmentation behavior enables fast quantitative analysis by applying multiple reaction monitoring. This provides a tool to analyze wax layer composition or determine whether seeds accumulate a desired wax ester profile. Besides the profiling method, we provide general information on wax ester analysis by the systematic definition of wax ester prototypes according to their collision-induced dissociation spectra. We applied the developed method for wax ester profiling of the well characterized jojoba seed oil and compared the profile with wax ester-accumulating Arabidopsis thaliana expressing the wax ester biosynthetic genes MaFAR and ScWS. Conclusions We developed a fast profiling method for wax ester analysis on the molecular species level. This method is suitable to screen large numbers of transgenic plants as well as other wax ester samples

  11. Short-chain aliphatic ester synthesis using Thermobifida fusca cutinase.

    PubMed

    Su, Lingqia; Hong, Ruoyu; Guo, Xiaojie; Wu, Jing; Xia, Yongmei

    2016-09-01

    Short-chain aliphatic esters are commonly used as fruit flavorings in the food industry. In this study, Thermobifida fusca (T. fusca) cutinase was used for the synthesis of aliphatic esters, and the maximum yield of ethyl caproate reached 99.2% at a cutinase concentration of 50U/ml, 40°C, and water content of 0.5%, representing the highest ester yield to date. The cutinase-catalyzed esterification displayed strong tolerance for water content (up to 8%) and acid concentration (up to 0.8M). At substrate concentrations ⩽0.8M, the ester yield remained above 80%. Moreover, ester yields of more than 98% and 95% were achieved for acids of C3-C8 and alcohols of C1-C6, respectively, indicating extensive chain length selectivity of the cutinase. These results demonstrate the superior ability of T. fusca cutinase to catalyze the synthesis of short-chain esters. This study provides the basis for industrial production of short-chain esters using T. fusca cutinase. PMID:27041308

  12. Formulation and evaluation of C-Ether fluids as lubricants useful to 260 C. [air breathing engines

    NASA Technical Reports Server (NTRS)

    Clark, F. S.; Miller, D. R.

    1980-01-01

    Three base stocks were evaluated in bench and bearing tests to determine their suitability for use at bulk oil temperatures (BOT) from -40 C to +260 C. A polyol ester gave good bearing tests at a bulk temperature of 218 C, but only a partially successful run at 274 C. These results bracket the fluid's maximum operating temperature between these values. An extensive screening program selected lubrication additives for a C-ether (modified polyphenyl ether) base stock. One formulation lubricated a bearing for 111 hours at 274 C (BOT), but this fluid gave many deposit related problems. Other C-ether blends produced cage wear or fatigue failures. Studies of a third fluid, a C-ether/disiloxane blend, consisted of bench oxidation and lubrication tests. These showed that some additives react differently in the blend than in pure C-ethers.

  13. Alcoholism, Alcohol, and Drugs

    ERIC Educational Resources Information Center

    Rubin, Emanuel; Lieber, Charles S.

    1971-01-01

    Describes research on synergistic effects of alcohol and other drugs, particularly barbiturates. Proposes biochemical mechanisms to explain alcoholics' tolerance of other drugs when sober, and increased sensitivity when drunk. (AL)

  14. Iridium-catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of syngas.

    PubMed

    Olsen, Esben P K; Madsen, Robert

    2012-12-01

    A new iridium-catalyzed reaction in which molecular hydrogen and carbon monoxide are cleaved from primary alcohols in the absence of any stoichiometric additives has been developed. The dehydrogenative decarbonylation was achieved with a catalyst generated in situ from [Ir(coe)(2)Cl](2) (coe = cyclooctene) and racemic 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (rac-BINAP) in a mesitylene solution saturated with water. A catalytic amount of lithium chloride was also added to improve the catalyst turnover. The reaction has been applied to a variety of primary alcohols and gives rise to products in good to excellent yields. Ethers, esters, imides, and aryl halides are stable under the reaction conditions, whereas olefins are partially saturated. The reaction is believed to proceed by two consecutive organometallic transformations that are catalyzed by the same iridium(I)-BINAP species. First, dehydrogenation of the primary alcohol to the corresponding aldehyde takes place, which is then followed by decarbonylation to the product with one less carbon atom. PMID:23108889

  15. Absorption of some glycol ethers through human skin in vitro.

    PubMed Central

    Dugard, P H; Walker, M; Mawdsley, S J; Scott, R C

    1984-01-01

    To assist evaluation of the hazards of skin contact with selected undiluted glycol ethers, their absorption across isolated human abdominal epidermis was measured in vitro. Epidermal membranes were set up in glass diffusion cells and, following an initial determination of permeability to tritiated water, excess undiluted glycol ether was applied to the outer surface for 8 hr. The appearance of glycol ether in an aqueous "receptor" phase bathing the underside of the epidermis was quantified by a gas chromatographic technique. A final determination of tritiated water permeability was compared with initial values to establish any irreversible alterations in epidermal barrier function induced by contact with the glycol ethers. 2-methoxyethanol (EM) was most readily absorbed (mean steady rate 2.82 mg/cm2/hr), and a relatively high absorption rate (1.17 mg/cm2/hr) was also apparent for 1-methoxypropan-2-ol (PM). There was a trend of reducing absorption rate with increasing molecular weight or reducing volatility for monoethylene glycol ethers (EM, 2.82 mg/cm2/hr; 2-ethoxyethanol, EE, 0.796 mg/cm2/hr; 2-butoxyethanol, EB, 0.198 mg/cm2/hr) and also within the diethylene glycol series: 2-(2-methoxyethoxy) ethanol (DM, 0.206 mg/cm2/hr); 2-(2-ethoxyethoxy) ethanol (DE, 0.125 mg/cm2/hr) and 2-(2-butoxyethoxy) ethanol (DB, 0.035 mg/cm2/hr). The rate of absorption of 2-ethoxyethyl acetate (EEAc) was similar to that of the parent alcohol, EE. Absorption rates of diethylene glycol ethers were slower than their corresponding monoethylene glycol equivalents. Combination of intrinsic toxicity and ability to pass across skin contribute to assessment of hazards of contact with undiluted glycol ethers. PMID:6499804

  16. Poly(arylene ether)s That Resist Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul; Smith, Joseph G., Jr.

    1994-01-01

    Novel poly(arylene ether)s containing phosphine oxide (PAEPO's) made via aromatic nucleophilic displacement reactions of activated aromatic dihalides (or, in some cases, activated aromatic dinitro compounds) with new bisphenol monomers containing phosphine oxide. Exhibited favorable combination of physical and mechanical properties and resistance to monatomic oxygen in oxygen plasma environment. Useful as adhesives, coatings, films, membranes, moldings, and composite matrices.

  17. Dichloromethyl alkyl ethers and sulfides in the Reformatskii reaction

    SciTech Connect

    Lapkin, I.I.; Fotin, V.V.

    1986-09-10

    A study was carried out on the reaction of dichloromethyl alkyl ethers and sulfides with ..cap alpha..-brominated esters in the presence of zinc resulting in the formation of either ..cap alpha..-alkyl-..beta..-alkoxyacrylates (or ..cap alpha..-alkyl-..beta..-alkylthioacrylates) or ..cap alpha..,..cap alpha..,..cap alpha..',..cap alpha..'-tetramethyl-..beta..-alkoxyglutaric acid (or ..cap alpha..,..cap alpha..,..cap alpha..',..cap alpha..'-tetramethyl-..beta..-alkylthioglutaric acid) depending on the structure of the starting bromoester. PMR and IR spectroscopy indicates the geometry of the ..cap alpha..-alkyl-..beta..-alkoxyacrylates and ..cap alpha..-alkyl-..beta..-alkylthioacrylates.

  18. Ether and Relativity

    NASA Astrophysics Data System (ADS)

    Farhoudi, Mehrdad; Yousefian, Maysam

    2016-05-01

    We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism.

  19. Removal of cholesteryl ester from hepatic reticuloendothelial cells in vivo is not enhanced by plasma cholesteryl ester transfer protein.

    PubMed

    Stein, O; Dabach, Y; Hollander, G; Stein, Y

    1991-01-28

    The putative role of cholesteryl ester transfer protein (CETP) in the removal of cholesteryl ester from hepatic reticuloendothelial cells in vivo was studied in hamsters. The parameter tested was retention of [3H]cholesteryl linoleyl ether ([3H]CLE), a nonhydrolysable analog of cholesteryl ester, in the liver after injection of [3H]CLE labeled acetylated LDL, which is targetted to nonparenchymatous littoral cells. In hamsters fed laboratory chow, plasma cholesteryl ester transfer activity (CETA) was 10.6 +/- 0.9 units and the retention of [3H]CLE in the liver 28 days after injection was 86% of the 4 h value. It was about 55% in rats fed the same diet, in which CETA was not detectable. When the diet was supplemented with 2% cholesterol and 15% margarine, CETA activity in hamsters increased 2-fold, yet no change in retention of [3H]CLE in liver was seen after 28 days. In rats, the retention of [3H]CLE in the liver was also not changed by the dietary fat supplementation. These results do not support the role of CETP in vivo in removal of cholesteryl ester from intact reticuloendothelial cells. PMID:1998742

  20. Fatty esters from vegetable oils for use as a diesel fuel

    SciTech Connect

    Freedman, B.; Pryde, E.H.

    1982-01-01

    Transesterification of sunflower and soybean oils to fatty esters has been carried out to study reaction variables such as: (1) molar ratio of alcohol to vegetable oil, (2) alcohol type (methanol, ethanol, and 1-butanol), (3) catalyst type (alkaline and acidic), and (4) reaction temperature (60/sup 0/, 45/sup 0/, and 32/sup 0/C). These studies showed that ester formation was 90 to 98% complete at the respective molar ratios of methanol/sunflower oil of 4:1 and 6:1. All three alcohols produced high yields of esters. Alkaline catalysts were much more effective than acid catalysts. At both 45/sup 0/ and 60/sup 0/, 97% of methyl esters were produced in 1 hr. 5 figures.

  1. Allene ether Nazarov cyclization.

    PubMed

    Tius, Marcus A

    2014-05-01

    The ease of synthesis and the exceptional reactivity of alkoxyallenes has led to their use in a large number of highly diverse applications. This Report describes their use in various versions of the allene ether Nazarov cyclization. Following a brief introduction to the Nazarov cyclization (Section 1), the oxidative cyclization of vinyl alkoxyallenes is discussed first (Section 2). Nazarov cyclizations of α-alkoxyallenyl vinyl ketones and of α-alkoxyallenyl vinyl tertiary carbinols are covered (Section 3). The discovery and the subsequent rational design of acetals that serve as chiral auxiliaries on the allene in highly enantioselective Nazarov cyclizations is explained (Section 4). Interrupted Nazarov cyclizations of alkoxyallenes that are generated in situ from the isomerization of propargyl ethers on solid supports are discussed, including the evolution of a highly diastereoselective, chiral auxiliary controlled version of the reaction. Some applications of the methodology to natural products total synthesis have been included so as to provide the reader with benchmarks with which to judge the utility of the methodology. PMID:24196585

  2. Increased production of wax esters in transgenic tobacco plants by expression of a fatty acid reductase:wax synthase gene fusion.

    PubMed

    Aslan, Selcuk; Hofvander, Per; Dutta, Paresh; Sun, Chuanxin; Sitbon, Folke

    2015-12-01

    Wax esters are hydrophobic lipids consisting of a fatty acid moiety linked to a fatty alcohol with an ester bond. Plant-derived wax esters are today of particular concern for their potential as cost-effective and sustainable sources of lubricants. However, this aspect is hampered by the fact that the level of wax esters in plants generally is too low to allow commercial exploitation. To investigate whether wax ester biosynthesis can be increased in plants using transgenic approaches, we have here exploited a fusion between two bacterial genes together encoding a single wax ester-forming enzyme, and targeted the resulting protein to chloroplasts in stably transformed tobacco (Nicotiana benthamiana) plants. Compared to wild-type controls, transgenic plants showed both in leaves and stems a significant increase in the total level of wax esters, being eight-fold at the whole plant level. The profiles of fatty acid methyl ester and fatty alcohol in wax esters were related, and C16 and C18 molecules constituted predominant forms. Strong transformants displayed certain developmental aberrations, such as stunted growth and chlorotic leaves and stems. These negative effects were associated with an accumulation of fatty alcohols, suggesting that an adequate balance between formation and esterification of fatty alcohols is crucial for a high wax ester production. The results show that wax ester engineering in transgenic plants is feasible, and suggest that higher yields may become achieved in the near future. PMID:26138876

  3. Kenaf methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Additional or alternative feedstocks are one of the major areas of interest regarding biodiesel. In this paper, for the first time, the fuel properties of kenaf (Hibiscus cannabinus L.) seed oil methyl esters are comprehensively reported. This biodiesel is also relatively unique by containing small ...

  4. Kapok oil methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increased need for biodiesel feedstocks has caused various vegetable oils to be examined for this purpose. In the present work, the methyl esters of kapok (Ceiba pentandra) oil were prepared. The essential fuel properties were comprehensively determined and evaluated in comparison to specificati...

  5. meso-Ester Corroles.

    PubMed

    Canard, Gabriel; Gao, Di; D'Aléo, Anthony; Giorgi, Michel; Dang, Florian-Xuan; Balaban, Teodor Silviu

    2015-05-18

    The introduction of ester groups on the 5- and 15-meso positions of corroles stabilizes them against oxidation and induces a redshift of their absorption and emission spectra. These effects are studied through the photophysical and electrochemical characterization of up to 16 different 5,15-diester corroles, in which the third meso position is free or occupied by an aryl group, a long alkyl chain, or an ester moiety. Single-crystal X-ray structure analysis of five 5,15-diestercorroles and DFT and time-dependent DFT calculations show that the strong electron-withdrawing character of the 5,15 ester substituents is reinforced by their π overlap with the macrocyclic aromatic system. The crystal packing of corroles 2, 4, 6, 9, and 15 features short distances between chromophores that are stacked into columns thanks to the low steric hindrance of meso-ester groups. This close packing is partially due to intermolecular interactions that involve inner hydrogen and nitrogen atoms, and thereby, stabilize a single, identical corrole tautomeric form. PMID:25786789

  6. Alcohol Alert

    MedlinePlus

    ... Us You are here Home » Alcohol Alert Alcohol Alert The NIAAA Alcohol Alert is a quarterly bulletin that disseminates important research ... text. To order single copies of select Alcohol Alerts, see ordering Information . To view publications in PDF ...

  7. Alcoholism - resources

    MedlinePlus

    Resources - alcoholism ... The following organizations are good resources for information on alcoholism : Alcoholics Anonymous -- www.aa.org Al-Anon/Alateen -- www.al-anon.org/home National Institute on Alcohol ...

  8. Alcoholic ketoacidosis

    MedlinePlus

    Ketoacidosis - alcoholic ... Alcoholic ketoacidosis is caused by very heavy alcohol use. It most often occurs in a malnourished person ... Symptoms of alcoholic ketoacidosis include: Nausea and vomiting ... Changed level of alertness, which may lead to coma Confusion ...

  9. Alcohol Facts

    MedlinePlus

    ... raquo Alcohol Facts Alcohol Facts Listen Drinks like beer, malt liquor, wine, and hard liquor contain alcohol. Alcohol is the ingredient that gets you drunk. Hard liquor—such as whiskey, rum, or gin—has more ...

  10. Alcoholic neuropathy

    MedlinePlus

    Neuropathy - alcoholic; Alcoholic polyneuropathy ... The exact cause of alcoholic neuropathy is unknown. It likely includes both a direct poisoning of the nerve by the alcohol and the effect of poor nutrition ...

  11. Differences in Substrate Specificities of Five Bacterial Wax Ester Synthases

    PubMed Central

    Wahlen, Bradley D.; Garner, EmmaLee; Wei, Jiashi; Seefeldt, Lance C.

    2012-01-01

    Wax esters are produced in certain bacteria as a potential carbon and energy storage compound. The final enzyme in the biosynthetic pathway responsible for wax ester production is the bifunctional wax ester synthase/acyl-coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT), which utilizes a range of fatty alcohols and fatty acyl-CoAs to synthesize the corresponding wax ester. We report here the isolation and substrate range characterization for five WS/DGAT enzymes from four different bacteria: Marinobacter aquaeolei VT8, Acinetobacter baylyi, Rhodococcus jostii RHA1, and Psychrobacter cryohalolentis K5. The results from kinetic studies of isolated enzymes reveal a differential activity based on the order of substrate addition and reveal subtle differences between the substrate selectivity of the different enzymes. These in vitro results are compared to the wax ester and triacylglyceride product profiles obtained from each organism grown under neutral lipid accumulating conditions, providing potential insights into the role that the WS/DGAT enzyme plays in determining the final wax ester products that are produced under conditions of nutrient stress in each of these bacteria. Further, the analysis revealed that one enzyme in particular from M. aquaeolei VT8 showed the greatest potential for future study based on rapid purification and significantly higher activity than was found for the other isolated WS/DGAT enzymes. The results provide a framework to test prospective differences between these enzymes for potential biotechnological applications such as high-value petrochemicals and biofuel production. PMID:22685145

  12. Functionalization of poly(aryl ether ether ketone)

    SciTech Connect

    Wang, Fei; Roovers, J.

    1993-12-31

    Bromomethyl and dibromomethyl substituted poly(aryl ether ether ketone) have been prepared from methyl poly(aryl ether ether ketone) by bromination with bromine. These brominated polymers are intermediates that can be further functionalized by: hydrolysis, oxidation, substitution etc. A series of new functionalized PEEK polymers has been prepared. The functional group includes -CH{sub 2}OH, -CH{sub 2}OCH{sub 3}, -CHO, -COOH, -COOCH{sub 3}, -CH{sub 2}CN, -CH{sub 2}COOH, -CH{sub 2}OCOCH{sub 3}, -CH{sub 2}N{sup +}H(CH{sub 2}CH{sub 3}){sub 2}Br{sup {minus}}, -CH{sub 2}N(CH{sub 2}CH{sub 3}){sub 2}, -CH{sub 2}N{sup +}H(CH{sub 2}CH{sub 3}){sub 3}Br{sup {minus}}.

  13. Polyarylene Ethers with Improved Properties

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M. (Inventor); Jensen, B. J. (Inventor); Havens, S. J. (Inventor)

    1986-01-01

    This invention relates to novel polyarylene ethers which possess the combination of high strength, toughness, and high use temperature with ease of extrusion and formation into complex objects. These polyarylene ethers are suitable for use in adhesives, coatings, films, membranes, and composite matrices. The polyarylene ethers of this invention are the polycondensation products from the reaction of either 1,3-bis (4-chloro or fluorobenzoyl) benzene with any one of the following bisphenolic compounds: bis (3-hydroxyphenyl) methane; bis (4-hydroxyphenyl) methane; 1,1-dimethyl-bis (4-hydroxyphenyl)methane, or 9,9-bis (4-hydroxyphenyl) fluorene. Random and block copolymers are also comprehended.

  14. Imide/Arylene Ether Copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.; Hergenrother, Paul M.; Bass, Robert G.

    1991-01-01

    New imide/arylene ether copolymers prepared by reacting anhydride-terminated poly(amic acids) with amine-terminated poly(arylene ethers) in polar aprotic solvents. Each resulting copolymer may have one glass-transition temperature or two, depending on chemical structure and/or compatibility of block units. Most of copolymers form tough, solvent-resistant films with high tensile properties. Films cast from solution tough and flexible, and exhibit useful thermal and mechanical properties. Potentially useful as moldings, adhesives, or composite matrices. Because of flexible arylene ether blocks, these copolymers easier to process than polyimides.

  15. Alcohol Alert: Genetics of Alcoholism

    MedlinePlus

    ... and Reports » Alcohol Alert » Alcohol Alert Number 84 Alcohol Alert Number 84 Print Version The Genetics of ... immune defense system. Genes Encoding Enzymes Involved in Alcohol Breakdown Some of the first genes linked to ...

  16. Regioselective Alkoxycarbonylation of Allyl Phenyl Ethers Catalyzed by Pd/dppb Under Syngas Conditions.

    PubMed

    Amézquita-Valencia, Manuel; Alper, Howard

    2016-05-01

    A simple and regioselective synthesis of phenoxy esters and phenylthio esters is reported. The products are obtained by selective alkoxycarbonylation catalyzed by Pd2(dba)3, 1,4-bis(diphenylphisphino)butane (dppb), and syngas (CO/H2) in chloroform/alcohol. This methodology affords bifunctional products in good yield with excellent n-selectivity and without the need to use additives. PMID:27075974

  17. Rhodium(III)-catalyzed C-H activation/annulation with vinyl esters as an acetylene equivalent.

    PubMed

    Webb, Nicola J; Marsden, Stephen P; Raw, Steven A

    2014-09-19

    The behavior of electron-rich alkenes in rhodium-catalyzed C-H activation/annulation reactions is investigated. Vinyl acetate emerges as a convenient acetylene equivalent, facilitating the synthesis of sixteen 3,4-unsubstituted isoquinolones, as well as select heteroaryl-fused pyridones. The complementary regiochemical preferences of enol ethers versus enol esters/enamides is discussed. PMID:25165993

  18. PTR-MS study of esters in water and water/ethanol solutions

    NASA Astrophysics Data System (ADS)

    Aprea, Eugenio; Biasioli, Franco; Märk, Tilmann D.; Gasperi, Flavia

    2007-04-01

    Esters strongly influence the perceived aroma of alcoholic beverages and their rapid monitoring can play an important role in the quality control of these products. Proton transfer reaction mass spectrometry (PTR-MS) allows the rapid and non invasive monitoring of foodstuff but there is still a lack of information about the proton transfer induced fragmentation and on the effect of high ethanol concentration. PTR-MS fragmentation patterns of 21 esters are reported, most of them for the first time. For linear methyl and ethyl esters the fragmentation dependence on E/N was also evaluated. Acetate esters, with exception of methyl acetate, show as main peaks the characteristic fragment ions at m/z 61 and m/z 43, whereas propanoate esters, but methyl propanoate, exhibit as main peaks the typical signals at m/z 75 and m/z 57. For all the other esters, here reported, the spectra are dominated by the protonated molecular ion. For methyl and ethyl esters we also report, in many cases for the first time, the water-solution/air partition coefficients (Henry's law constant) and the ethanol-solution/air partition coefficients at different ethanol concentrations. The information provided in this work may be useful as a basis for further studies for the identification and quantification of esters in the headspace of alcoholic beverages extending the application field of PTR-MS.

  19. The ESTER project

    NASA Astrophysics Data System (ADS)

    Rieutord, M.; Dintrans, B.; Lignières, F.; Corbard, T.; Pichon, B.

    2005-12-01

    The ESTER project aims at building a stellar evolution code in two dimensions of space for the study of effects of rotation. The numerical scheme is based on spectral methods with a spherical harmonic decomposition in the horizontal direction and a Chebyshev polynomial expansion in the vertical direction. Coordinates adapted to the centrifugally distorted shape are mapped to spherical coordinates. First tests on rotating polytropes are presented.

  20. Dehydrogenative α-oxygenation of ethers with an iron catalyst.

    PubMed

    Gonzalez-de-Castro, Angela; Robertson, Craig M; Xiao, Jianliang

    2014-06-11

    Selective α-oxidation of ethers under aerobic conditions is a long-pursued transformation; however, a green and efficient catalytic version of this reaction remains challenging. Herein, we report a new family of iron catalysts capable of promoting chemoselective α-oxidation of a range of ethers with excellent mass balance and high turnover numbers under 1 atm of O2 with no need for any additives. Unlike metalloenzymes and related biomimetics, the catalyst produces H2 as the only byproduct. Mechanistic investigations provide evidence for an unexpected two-step reaction pathway, which involves dehydrogenative incorporation of O2 into the ether to give a peroxobisether intermediate followed by cleavage of the peroxy bond to form two ester molecules, releasing stoichiometric H2 gas in each step. The operational simplicity and environmental friendliness of this methodology affords a useful alternative for performing oxidation, while the unique ability of the catalyst in oxygenating a substrate via dehydrogenation points to a new direction for understanding metalloenzymes and designing new biomimetic catalysts. PMID:24835531

  1. Mode of Action Studies on Nitrodiphenyl Ether Herbicides 1

    PubMed Central

    Bowyer, John R.; Hallahan, Beverly J.; Camilleri, Patrick; Howard, Joy

    1989-01-01

    The nitrodiphenyl ether herbicide 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitroacetophenone oxime-o-(acetic acid, methyl ester) (DPEI) induces light- and O2-dependent lipid peroxidation and chlorophyll (Chl) bleaching in the green alga Scenedesmus obliquus. Under conditions of O2-limitation, these effects are diminished by prometyne and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), both inhibitors of photosynthetic electron transport. Mutants in which photosynthetic electron transport is blocked are also resistant to DPEI under conditions of O2-limitation. Light- and O2-dependent lipid peroxidation and Chl bleaching are also induced by 5-[2-chloro-4-(trifluoromethyl)phenoxy]-3-methoxyphthalide (DPEII), a diphenyl ether whose redox properties preclude reduction by photosystem I. However, these effects of DPEII are also inhibited by DCMU. Under conditions of high aeration, DCMU does not protect Scenedesmus cells from Chl bleaching induced by DPEI, but does protect against paraquat. DPEI, but not paraquat, induces tetrapyrrole formation in treated cells in the dark. This is also observed in a mutant lacking photosystem I but is suppressed under conditions likely to lead to O2 limitation. Our results indicate that, in contrast to paraquat, the role of photosynthetic electron transport in diphenyl ether toxicity in Scenedesmus is not to reduce the herbicide to a radical species which initiates lipid peroxidation. Its role is probably to maintain a sufficiently high O2 concentration, through water-splitting, in the algal suspension. PMID:16666600

  2. Rearrangements of Cycloalkenyl Aryl Ethers.

    PubMed

    Törincsi, Mercedesz; Nagy, Melinda; Bihari, Tamás; Stirling, András; Kolonits, Pál; Novak, Lajos

    2016-01-01

    Rearrangement reactions of cycloalkenyl phenol and naphthyl ethers and the acid-catalyzed cyclization of the resulting product were investigated. Claisen rearrangement afforded 2-substituted phenol and naphthol derivatives. Combined Claisen and Cope rearrangement resulted in the formation of 4-substituted phenol and naphthol derivatives. In the case of cycloocthylphenyl ether the consecutive Claisen and Cope rearrangements were followed by an alkyl migration. The mechanism of this novel rearrangement reaction is also discussed. PMID:27104504

  3. Imide/arylene ether copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor); Bass, Robert G. (Inventor)

    1992-01-01

    Imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly(arylene ethers) in polar aprotic solvents and by chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The resulting block copolymers have one glass transition temperature or two, depending upon the particular structure and/or the compatibility of the block units. Most of these block copolymers form tough, solvent resistant films with high tensile properties.

  4. Selective, nickel-catalyzed hydrogenolysis of aryl ethers.

    PubMed

    Sergeev, Alexey G; Hartwig, John F

    2011-04-22

    Selective hydrogenolysis of the aromatic carbon-oxygen (C-O) bonds in aryl ethers is an unsolved synthetic problem important for the generation of fuels and chemical feedstocks from biomass and for the liquefaction of coal. Currently, the hydrogenolysis of aromatic C-O bonds requires heterogeneous catalysts that operate at high temperature and pressure and lead to a mixture of products from competing hydrogenolysis of aliphatic C-O bonds and hydrogenation of the arene. Here, we report hydrogenolyses of aromatic C-O bonds in alkyl aryl and diaryl ethers that form exclusively arenes and alcohols. This process is catalyzed by a soluble nickel carbene complex under just 1 bar of hydrogen at temperatures of 80 to 120°C; the relative reactivity of ether substrates scale as Ar-OAr>Ar-OMe>ArCH(2)-OMe (Ar, Aryl; Me, Methyl). Hydrogenolysis of lignin model compounds highlights the potential of this approach for the conversion of refractory aryl ether biopolymers to hydrocarbons. PMID:21512027

  5. Green polymer chemistry VIII: synthesis of halo-ester-functionalized poly(ethylene glycol)s via enzymatic catalysis.

    PubMed

    Castano, Marcela; Seo, Kwang Su; Kim, Eun Hye; Becker, Matthew L; Puskas, Judit E

    2013-09-01

    Halo-ester-functionalized poly(ethylene glycol)s (PEGs) are successfully prepared by the transesterification of alkyl halo-esters with PEGs using Candida antarctica lipase B (CALB) as a biocatalyst under the solventless conditions. Transesterifications of chlorine, bromine, and iodine esters with tetraethylene glycol monobenzyl ether (BzTEG) are quantitative in less than 2.5 h. The transesterification of halo-esters with PEGs are complete in 4 h. (1) H and (13) C NMR spectroscopy with MALDI-ToF and ESI mass spectrometry confirm the structure and purity of the products. This method provides a convenient and "green" process to effectively produce halo-ester PEGs. PMID:23877930

  6. Tumour scanning with indium-111 dihaematoporphyrin ether.

    PubMed Central

    Quastel, M. R.; Richter, A. M.; Levy, J. G.

    1990-01-01

    Photofrin II (dihaematoporphyrin ether/ester, DHE) was labelled with indium-111 and its biodistribution in tumour bearing mice compared with that of 111In chloride. The uptake and clearance of 111In labelled DHE differed markedly from that of indium-111 chloride in that the former was not taken up by the tissues as much as the latter. Scintillation scanning with a gamma-camera showed marked uptake of both 111In agents at the site of the tumour, but a much lower tissue background (excluding the abdominal organs) for the mice given 111In DHE. Tumour:muscle ratios of dissected tissues were 2-3 times higher in 111In DHE treated animals as compared to the uptake of 111In chloride. There was a distinct difference in the pattern of distribution of the two 111In preparations in the tissues. The major accumulation of 111In chloride was in the kidneys, whereas the highest uptake of 111In DHE was in the liver, the organ in which unlabelled porphyrins accumulate. Extraction and testing of materials from tumours of 111In DHE treated animals indicated that most of the tumour extractable 111In had remained associated with the porphyrin in vivo up to 4 days after injection. Images Figure 1 PMID:2147858

  7. Gas Phase Spectroscopic Investigation of Chromate-Esters

    NASA Astrophysics Data System (ADS)

    Kaufman, Sydney H.; Weber, J. Mathias

    2012-06-01

    Chromate and dichromate ions are frequently used in the oxidation of alcohols. Chromate esters containing a Cr--O--C bridge are thought to be important intermediates in such reactions. We report the photofragment action spectra of two chromate ester complexes in the UV and visible regions, both of which primarily undergo cleavage of the chromate ester bond resulting in reduction of the chromate from Cr(VI) to Cr(V). Comparison to the UV/Vis absorption spectrum of a methanolic dichromate solution suggests the electronic transitions are the same ligand-to-metal charge transfer transitions in both environments. Comparing the spectral features for different fragment channels leads to insight into the energetics and fragmentation mechanism of these species.

  8. Space, Time, Ether, and Kant

    NASA Astrophysics Data System (ADS)

    Wong, Wing-Chun Godwin

    This dissertation focused on Kant's conception of physical matter in the Opus postumum. In this work, Kant postulates the existence of an ether which fills the whole of space and time with its moving forces. Kant's arguments for the existence of an ether in the so-called Ubergang have been acutely criticized by commentators. Guyer, for instance, thinks that Kant pushes the technique of transcendental deduction too far in trying to deduce the empirical ether. In defense of Kant, I held that it is not the actual existence of the empirical ether, but the concept of the ether as a space-time filler that is subject to a transcendental deduction. I suggested that Kant is doing three things in the Ubergang: First, he deduces the pure concept of a space-time filler as a conceptual hybrid of the transcendental object and permanent substance to replace the category of substance in the Critique. Then he tries to prove the existence of such a space-time filler as a reworking of the First Analogy. Finally, he takes into consideration the empirical determinations of the ether by adding the concept of moving forces to the space -time filler. In reconstructing Kant's proofs, I pointed out that Kant is absolutely committed to the impossibility of action-at-a-distance. If we add this new principle of no-action-at-a-distance to the Third Analogy, the existence of a space-time filler follows. I argued with textual evidence that Kant's conception of ether satisfies the basic structure of a field: (1) the ether is a material continuum; (2) a physical quantity is definable on each point in the continuum; and (3) the ether provides a medium to support the continuous transmission of action. The thrust of Kant's conception of ether is to provide a holistic ontology for the transition to physics, which can best be understood from a field-theoretical point of view. This is the main thesis I attempted to establish in this dissertation.

  9. Sulfonimide-containing poly(arylene ether)s and poly(arylene ether sulfone)s, methods for producing the same, and uses thereof

    DOEpatents

    Hofmann, Michael A.

    2006-11-14

    The present invention is directed to sulfonimide-containing polymers, specifically sulfonimide-containing poly(arylene ether)s and sulfonimide-containing poly(arylene ether sulfone)s, and processes for making the sulfonimide-containing poly(arylene ether)s and sulfonimide-containing poly(arylene ether sulfone)s, for use conductive membranes and fuel cells.

  10. Method of making alkyl esters

    DOEpatents

    Elliott, Brian

    2010-09-14

    Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70.degree. C. to about 120.degree. C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.

  11. REDUCTIVE ACTIVATION OF DIOXYGEN FOR DEGRADATION OF METHYL TERT-BUTYL ETHER BY BIFUNCTION

    EPA Science Inventory

    Bifunctional aluminum is prepared by sulfating aluminum metal with sulfuric acid. The use of bifunctional aluminum to degrade methyl tert-butyl ether (MTBE) in the presence of dioxygen has been examined using batch systems. Primary degradation products were tert-butyl alcohol, ...

  12. DETERMINATION OF SURFACTANT SODIUM LAURYL ETHER SULFATE BY ION PAIRING CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY DETECTION

    EPA Science Inventory

    A method for the determination of the anionic Steol CS-330 surfactant is described. CS-330 is a complex mixture of oligomers due to the various sizes of fatty alcohols and the number of moles of the ethoxylation. The main component of CS-330 is sodium lauryl ether sulfate (SLES)....

  13. Nickel-Catalyzed Intramolecular C-O Bond Formation: Synthesis of Cyclic Enol Ethers.

    PubMed

    Han, Seo-Jung; Doi, Ryohei; Stoltz, Brian M

    2016-06-20

    An efficient and exceptionally mild intramolecular nickel-catalyzed carbon-oxygen bond-forming reaction between vinyl halides and primary, secondary, and tertiary alcohols has been achieved. Zinc powder was found to be an essential additive for obtaining high catalyst turnover and yields. This operationally simple method allows direct access to cyclic vinyl ethers in high yields in a single step. PMID:27159831

  14. Preparation and Evaluation of a Series of Alpha-Hydroxy Ethers from 9,10-Epoxystearates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several novel alpha-hydroxy ethers were synthesized by treatment of isobutyl 9,10-epoxystearate with a number of aliphatic alcohols in the presence of acid catalyst in good overall yield from oleic acid. The materials low temperature behavior was analyzed through cloud point and pour point determi...

  15. Synthesis and Evaluation of Alpha-Hydroxy Ethers as Potential Biodiesel Additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several novel alpha-hydroxy ethers were synthesized by treatment of alkyl 9,10-epoxystearates with a number of alcohols in the presence of acid catalyst in good yield from oleic acid. The low temperature behavior of each material was analyzed through cloud point (CP) and pour point (PP) determinati...

  16. Metal ion complexation by ionizable crown ethers. Final report, January 1, 1988--June 30, 1994

    SciTech Connect

    Bartsch, R.A.

    1994-12-31

    During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. The ligands possess one or more ionizable group (carboxylic acid, phosphonic acid monoethyl ester, para-nitrophenol, phosphonic acid) attached to crown ether, monoazacrown ether or diazacrown ether frameworks. These novel chelating agents have either pendent or inward-facing proton-ionizable groups. Such lipophilic proton-ionizable crown ethers are designed for use in multiphase metal ion separations (solvent extraction, liquid membrane transport). In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The influence of structural variations within lipophilic acyclic polyether dicarboxylic acids upon competitive solvent extraction of alkaline earth cations has been probed. Also a new chromogenic, di-ionizable crown ether with extremely high selectivity for Hg{sup 2+} has been discovered.

  17. The Ether Lipid Precursor Hexadecylglycerol Causes Major Changes in the Lipidome of HEp-2 Cells

    PubMed Central

    Bergan, Jonas; Skotland, Tore; Sylvänne, Tuulia; Simolin, Helena; Ekroos, Kim; Sandvig, Kirsten

    2013-01-01

    The ether-lipid precursor sn-1-O-hexadecylglycerol (HG) can be used to compensate for early metabolic defects in ether-lipid biosynthesis. To investigate a possible metabolic link between ether-linked phospholipids and the rest of the cellular lipidome, we incubated HEp-2 cells with HG. Mass spectrometry analysis revealed major changes in the lipidome of HG-treated cells compared to that of untreated cells or cells treated with palmitin, a control substance for HG containing an acyl group instead of the ether group. We present quantitative data for a total of 154 species from 17 lipid classes. These species are those constituting more than 2% of their lipid class for most lipid classes, but more than 1% for the ether lipids and glycosphingolipids. In addition to the expected ability of HG to increase the levels of ether-linked glycerophospholipids with 16 carbon atoms in the sn-1 position, this precursor also decreased the amounts of glycosphingolipids and increased the amounts of ceramide, phosphatidylinositol and lysophosphatidylinositol. However, incubation with palmitin, the fatty acyl analogue of HG, also increased the amounts of ceramide and phosphatidylinositols. Thus, changes in these lipid classes were not ether lipid-dependent. No major effects were observed for the other lipid classes, and cellular functions such as growth and endocytosis were unaffected. The data presented clearly demonstrate the importance of performing detailed quantitative lipidomic studies to reveal how the metabolism of ether-linked glycerophospholipids is coupled to that of glycosphingolipids and ester-linked glycerophospholipids, especially phosphatidylinositols. PMID:24098742

  18. Synthesis and Characterization of bis(Tetrahydrofurfuryl) Ether.

    PubMed

    Stenger-Smith, John D; Baldwin, Lawrence; Chafin, Andrew; Goodman, Paul A

    2016-08-01

    Despite the availability of a large number of alkyl tetrahydrofurfuryl ethers that have a wide range of applications, pure bis(tetrahydrofurfuryl) ether (BTHFE) has not been previously synthesized. Here, we report the synthesis of BTHFE (consisting of the RR, SS, and meso stereoisomers) at greater than 99 % purity from tetrahydrofurfuryl alcohol, using (tetrahydrofuran-2-yl)methyl methanesulfonate as an intermediate. Additionally, we demonstrate that BTHFE can be used as a non-volatile solvent in poly(3,4-propylenedioxythiophene)-based supercapacitors. Supercapacitor devices employing solutions of the ionic liquid 1-ethyl-3-methyl-imidizolium bis(trifluoromethylsulfonyl)imide in BTHFE display similar performances to those prepared by using the neat ionic liquid as an electrolyte, although solution-based devices exhibit a somewhat higher resistance. PMID:27547636

  19. CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS

    SciTech Connect

    Kamil Klier; Richard G. Herman; James G.C. Shen; Qisheng Ma

    2000-08-31

    A novel 1,2-ethanediol, bis(hydrogen sulfate), disodium salt precursor-based solid acid catalyst with a zirconia substrate was synthesized and demonstrated to have significantly enhanced activity and high selectivity in producing methyl isobutyl ether (MIBE) or isobutene from methanol-isobutanol mixtures. The precursor salt was synthesized and provided by Dr. T. H. Kalantar of the M.E. Pruitt Research Center, Dow Chemical Co., Midland, MI 48674. Molecular modeling of the catalyst synthesis steps and of the alcohol coupling reaction is being carried out. A representation of the methyl transfer from the surface activated methanol molecule (left) to the activated oxygen of the isobutanol molecule (right) to form an ether linkage to yield MIBE is shown.

  20. Synthesis and Characterization of bis(Tetrahydrofurfuryl) Ether

    PubMed Central

    Stenger‐Smith, John D.; Baldwin, Lawrence; Chafin, Andrew

    2016-01-01

    Abstract Despite the availability of a large number of alkyl tetrahydrofurfuryl ethers that have a wide range of applications, pure bis(tetrahydrofurfuryl) ether (BTHFE) has not been previously synthesized. Here, we report the synthesis of BTHFE (consisting of the RR, SS, and meso stereoisomers) at greater than 99 % purity from tetrahydrofurfuryl alcohol, using (tetrahydrofuran‐2‐yl)methyl methanesulfonate as an intermediate. Additionally, we demonstrate that BTHFE can be used as a non‐volatile solvent in poly(3,4‐propylenedioxythiophene)‐based supercapacitors. Supercapacitor devices employing solutions of the ionic liquid 1‐ethyl‐3‐methyl‐imidizolium bis(trifluoromethylsulfonyl)imide in BTHFE display similar performances to those prepared by using the neat ionic liquid as an electrolyte, although solution‐based devices exhibit a somewhat higher resistance. PMID:27547636

  1. Tandem Bond-Forming Reactions of 1-Alkynyl Ethers.

    PubMed

    Minehan, Thomas G

    2016-06-21

    Electron-rich alkynes, such as ynamines, ynamides, and ynol ethers, are functional groups that possess significant potential in organic chemistry for the formation of carbon-carbon bonds. While the synthetic utility of ynamides has recently been expanded considerably, 1-alkynyl ethers, which possess many of the reactivity features of ynamides, have traditionally been far less investigated because of concerns about their stability. Like ynamides, ynol ethers are relatively unhindered to approach by functional groups present in the same or different molecules because of their linear geometry, and they can potentially form up to four new bonds in a single transformation. Ynol ethers also possess unique reactivity features that make them complementary to ynamides. Research over the past decade has shown that ynol ethers formed in situ from stable precursors engage in a variety of useful carbon-carbon bond-forming processes. Upon formation at -78 °C, allyl alkynyl ethers undergo a rapid [3,3]-sigmatropic rearrangement to form allyl ketene intermediates, which may be trapped with alcohol or amine nucleophiles to form γ,δ-unsaturated carboxylic acid derivatives. The process is stereospecific, takes place in minutes at cryogenic temperatures, and affords products containing (quaternary) stereogenic carbon atoms. Trapping of the intermediate allyl ketene with carbonyl compounds, epoxides, or oxetanes instead leads to complex α-functionalized β-, γ-, or δ-lactones, respectively. [3,3]-Sigmatropic rearrangement of benzyl alkynyl ethers also takes place at temperatures ranging from -78 to 60 °C to afford substituted 2-indanones via intramolecular carbocyclization of the ketene intermediate. tert-Butyl alkynyl ethers containing pendant di- and trisubstituted alkenes and enol ethers are stable to chromatographic isolation and undergo a retro-ene/[2 + 2] cycloaddition reaction upon mild thermolysis (90 °C) to afford cis-fused cyclobutanones and donor

  2. Release studies on niosomes containing fatty alcohols as bilayer stabilizers instead of cholesterol.

    PubMed

    Devaraj, Gopi N; Parakh, S R; Devraj, Ravi; Apte, S S; Rao, B Ramesh; Rambhau, D

    2002-07-15

    Monomers of some amphiphiles organize into bilayers to form liposomes and niosomes. Such bilayers are unstable or leaky and hence cholesterol is a common ingredient included to stabilize them. Cholesterol stabilizes bilayers, prevents leakiness, and retards permeation of solutes enclosed in the aqueous core of these vesicles. Other than cholesterol a material with good bilayer-stabilizing properties is yet to be identified. We have substituted cholesterol with fatty alcohols in niosomes containing polyglyceryl-3-di-isostearate (PGDS) and polysorbate-80 (PS-80) to explore their membrane-stabilizing property via permeation studies. Niosomes of polyglyceryl-3-di-isostearate, fatty alcohol/cholesterol, and polysorbate were prepared by ether injection method. Aqueous solution of ketorolac tromethamine (KT) was entrapped in them. The effects of alkyl chain length of fatty alcohols (C(12), C(14), C(16), C(18), and C(16+18)), of acyl chain length of polyoxyethylene sorbitan monoester surfactants, and of the molar ratio of lipid mixture on the release rate of ketorolac from niosomes were assessed by employing modified dissolution-dialysis method. Niosomes with cholesterol or fatty alcohols have exhibited a common release pattern. Niosomes containing fatty alcohol showed a considerably slower release rate of KT than those containing cholesterol. Based on the release rate, fatty alcohols can be ranked as stearylalcohol (MA), and polysorbate, the fatty acid chain length of polyoxyethylene sorbitan ester-type surfactants has influenced the release rate and encapsulation efficiency. Based on the release rate, polysorbates can be ranked as polysorbate-20 (C(12))

  3. Alcoholic ketoacidosis

    MedlinePlus

    ... attention improves the overall outlook. How severe the alcoholism is, and the presence of liver disease or ... A.M. Editorial team. Related MedlinePlus Health Topics Alcoholism and Alcohol Abuse Browse the Encyclopedia A.D. ...

  4. Alcohol withdrawal

    MedlinePlus

    ... counseling to discuss the long-term issue of alcoholism Testing and treatment for other medical problems linked ... following organizations are good resources for information on alcoholism: Alcoholics Anonymous -- www.aa.org Al-Anon/Alateen -- ...

  5. Alcoholic neuropathy

    MedlinePlus

    ... objects in the shoes Guarding the extremities to prevent injury from pressure Alcohol must be stopped to prevent the damage from ... The only way to prevent alcoholic neuropathy is not to drink excessive amounts of alcohol.

  6. Characteristics of Palm Fatty Acid Ester (PFAE), a New Vegetable Based Insulating Oil for Transformers

    NASA Astrophysics Data System (ADS)

    Suzuki, Takashi; Kanoh, Takaaki; Koide, Hidenobu; Hikosaka, Tomoyuki

    We have developed new vegetable based insulating oil for transformers called PFAE (Palm Fatty Acid Ester). PFAE has 0.6 times less viscosity and 1.3 times higher dielectric constant compared to mineral oil. The oxidative stability, biodegradability and acute toxicity to fish of PFAE has also been determined to be superior to mineral oil. In this paper, in order to optimize the characteristics of fatty acid esters originating from palm oil, several kinds of fatty acid alkyl esters were first synthesized in the laboratory by the molecular design technique and the transesterification from fatty acid methyl esters and alkyl alcohols. Next the electro-chemical characteristics of the fatty acid alkyl esters as insulating oil were analyzed.

  7. Facile synthesis of acid-labile polymers with pendent ortho esters.

    PubMed

    Cheng, Jing; Ji, Ran; Gao, Shi-Juan; Du, Fu-Sheng; Li, Zi-Chen

    2012-01-01

    This work presents a facile approach for preparation of acid-labile and biocompatible polymers with pendent cyclic ortho esters, which is based on the efficient and mild reactions between cyclic ketene acetal (CKA) and hydroxyl groups. Three CKAs, 2-ethylidene-1,3-dioxane (EDO), 2-ethylidene-1,3-dioxolane (EDL), and 2-ethylidene-4- methyl-1,3-dioxolane (EMD) were prepared from the corresponding cyclic vinyl acetals by catalytic isomerization of the double bond. The reaction of CKAs with different alcohols and diols was examined using trace of p-toluenesulfonic acid as a catalyst. For the monohydroxyl alcohols, cyclic ortho esters were formed by simple addition of the hydroxyl group toward CKAs with ethanol showing a much greater reactivity than iso-propanol. When 1,2- or 1,3-diols were used to react with the CKAs, we observed the isomerized cyclic ortho esters besides the simple addition products. Biocompatible polyols, that is, poly(2-hydroxyethyl acrylate) (PHEA) and poly(vinyl alcohol) (PVA) were then modified with CKAs, and the degree of substitution of the pendent ortho esters can be easily tuned by changing feed ratio. Both the small molecule ortho esters and the CKA-modified polymers demonstrate the pH-dependent hydrolysis profiles, which depend also on the chemical structure of the ortho esters as well as the polymer hydrophobicity. PMID:22176024

  8. Production of wax esters during aerobic growth of marine bacteria on isoprenoid compounds

    PubMed

    Rontani; Bonin; Volkman

    1999-01-01

    This paper describes the production of isoprenoid wax esters during the aerobic degradation of 6,10,14-trimethylpentadecan-2-one and phytol by four bacteria (Acinetobacter sp. strain PHY9, Pseudomonas nautica [IP85/617], Marinobacter sp. strain CAB [DSMZ 11874], and Marinobacter hydrocarbonoclasticus [ATCC 49840]) isolated from the marine environment. Different pathways are proposed to explain the formation of these compounds. In the case of 6,10, 14-trimethylpentadecan-2-one, these esters result from the condensation of some acidic and alcoholic metabolites produced during the biodegradation, while phytol constitutes the alcohol moiety of most of the esters produced during growth on this isoprenoid alcohol. The amount of these esters formed increased considerably in N-limited cultures, in which the ammonium concentration corresponds to conditions often found in marine sediments. This suggests that the bacterial formation of isoprenoid wax esters might be favored in such environments. Although conflicting evidence exists regarding the stability of these esters in sediments, it seems likely that, under some conditions, bacterial esterification can enhance the preservation potential of labile compounds such as phytol. PMID:9872783

  9. Characterization of Wax Esters by Electrospray Ionization Tandem Mass Spectrometry: Double Bond Effect and Unusual Product Ions

    PubMed Central

    Chen, Jianzhong; Green, Kari B; Nichols, Kelly K

    2015-01-01

    A series of different types of wax esters (represented by RCOOR′) were systematically studied by using electrospray ionization (ESI) collision-induced dissociation tandem mass spectrometry (MS/MS) along with pseudo MS3 (in-source dissociation combined with MS/MS) on a quadrupole time-of-flight (Q-TOF) mass spectrometer. The tandem mass spectra patterns resulting from dissociation of ammonium/proton adducts of these wax esters were influenced by the wax ester type and the collision energy applied. The product ions [RCOOH2]+, [RCO]+ and [RCO – H2O]+ that have been reported previously were detected; however, different primary product ions were demonstrated for the three wax ester types including: 1) [RCOOH2]+ for saturated wax esters, 2) [RCOOH2]+, [RCO]+ and [RCO – H2O]+ for unsaturated wax esters containing only one double bond in the fatty acid moiety or with one additional double bond in the fatty alcohol moiety, and 3) [RCOOH2]+ and [RCO]+ for unsaturated wax esters containing a double bond in the fatty alcohol moiety alone. Other fragments included [R′]+ and several series of product ions for all types of wax esters. Interestingly, unusual product ions were detected, such as neutral molecule (including water, methanol and ammonia) adducts of [RCOOH2]+ ions for all types of wax esters and [R′ – 2H]+ ions for unsaturated fatty acyl-containing wax esters. The patterns of tandem mass spectra for different types of wax esters will inform future identification and quantification approaches of wax esters in biological samples as supported by a preliminary study of quantification of isomeric wax esters in human meibomian gland secretions. PMID:26178197

  10. Production of wax esters in plant seed oils by oleosomal cotargeting of biosynthetic enzymes[S

    PubMed Central

    Heilmann, Mareike; Iven, Tim; Ahmann, Katharina; Hornung, Ellen; Stymne, Sten; Feussner, Ivo

    2012-01-01

    Wax esters are neutral lipids exhibiting desirable properties for lubrication. Natural sources have traditionally been whales. Additionally some plants produce wax esters in their seed oil. Currently there is no biological source available for long chain length monounsaturated wax esters that are most suited for industrial applications. This study aimed to identify enzymatic requirements enabling their production in oilseed plants. Wax esters are generated by the action of fatty acyl-CoA reductase (FAR), generating fatty alcohols and wax synthases (WS) that esterify fatty alcohols and acyl-CoAs to wax esters. Based on their substrate preference, a FAR and a WS from Mus musculus were selected for this study (MmFAR1 and MmWS). MmWS resides in the endoplasmic reticulum (ER), whereas MmFAR1 associates with peroxisomes. The elimination of a targeting signal and the fusion to an oil body protein yielded variants of MmFAR1 and MmWS that were cotargeted and enabled wax ester production when coexpressed in yeast or Arabidopsis. In the fae1 fad2 double mutant, rich in oleate, the cotargeted variants of MmFAR1 and MmWS enabled formation of wax esters containing >65% oleyl-oleate. The data suggest that cotargeting of unusual biosynthetic enzymes can result in functional interplay of heterologous partners in transgenic plants. PMID:22878160

  11. Destruction of Leishmania mexicana amazonensis amastigotes within macrophages by lysosomotropic amino acid esters

    PubMed Central

    1986-01-01

    Leishmania amastigotes parasitize almost exclusively the mononuclear phagocytes of mammals. The organisms survive and multiply within acidified vacuoles (parasitophorous vacuoles; p.v.) akin to phagolysosomes. Certain amino acid esters are known to accumulate in and disrupt lysosomes. We postulated that, since Leishmania possess lysosome-like organelles, they may be susceptible to the potentially high ester concentrations attained in the p.v. We report here that L- amino acid esters can rapidly destroy intracellular Leishmania at concentrations that do not appear to damage the host cells. L-leu-OMe, which cured greater than or equal to 90% of infected macrophages at 0.8 mM concentrations, was used in most of the experiments. L-leu-OMe was only active after infection, implying inefficient transfer from secondary lysosomes to the p.v. Parasite destruction had several features in common with lysosomal and leukocyte damage induced by the esters, i.e., inactivity of D-amino acid esters, a marked pH dependence and increased killing after ester pulses at lower temperatures. Killing depended on the amino acid and on the ester substitution. The most active of the methyl esters assayed was that of leucine, followed by those of tryptophan, glutamic acid, methionine, phenylalanine, and tyrosine. Methyl esters of seven other amino acids were inactive when tested at up to 10 mM concentrations. Among leucine esters studied, benzyl ester was sixfold more active than the methyl homolog. The dipeptide L-leu-leu-OMe produced 90% cure at 0.08 mM concentrations. Leishmanicidal activity could be related to penetration of the parasites by the esters or to toxic ester hydrolysis products released in the p.v. The first hypothesis is supported by the pH-dependent destruction of isolated amastigotes by the esters. Furthermore, relatively high concentrations of L-leucine, methanol, or benzyl alcohol were not demonstrably toxic to the amastigotes. We postulate that ester concentrations

  12. Atmospheric Hydrogenation of Esters Catalyzed by PNP-Ruthenium Complexes with an N-Heterocyclic Carbene Ligand.

    PubMed

    Ogata, Osamu; Nakayama, Yuji; Nara, Hideki; Fujiwhara, Mitsuhiko; Kayaki, Yoshihito

    2016-08-01

    New pincer ruthenium complexes bearing a monodentate N-heterocyclic carbene ligand were synthesized and demonstrated as powerful hydrogenation catalysts. With an atmospheric pressure of hydrogen gas, aromatic, heteroaromatic, and aliphatic esters as well as lactones were converted into the corresponding alcohols at 50 °C. This reaction protocol offers reliable access to alcohols using an easy operational setup. PMID:27439106

  13. Phosphorylation of Kraft fibers with phosphate esters.

    PubMed

    Shi, Ying; Belosinschi, Dan; Brouillette, François; Belfkira, Ahmed; Chabot, Bruno

    2014-06-15

    Phosphate esters, derived from two different long-chain aliphatic alcohols, were used as phosphorylating reagents for Kraft pulp fibers. High phosphorus contents and almost non-degraded fibers were obtained by following this pathway. The phosphorylation efficiency was influenced by the alkyl chain length of PEs since the phosphorus content in modified fibers was higher for the shorter chain reagent. Due to the heterogeneous reaction environment, the amount of grafted phosphorus was found to be almost three times higher at the surface than in the bulk of the fibers. Analyses also indicated that the phosphorus was bonded to fibers as a phosphate-like structure. Furthermore, the situation seemed to be different for the fiber surface where significant amounts of phosphorus were present in more complex structures like pyrophosphate or even oligo-phosphate. PMID:24721058

  14. Catalytic Asymmetric Synthesis of Chiral Allylic Esters

    PubMed Central

    Cannon, Jeffrey S.; Kirsch, Stefan F.; Overman, Larry E.

    2010-01-01

    A broadly useful catalytic enantioselective synthesis of branched allylic esters from prochiral (Z)-2-alkene-1-ols has been developed. The starting allylic alcohol is converted to its trichloroacetimidate intermediate by reaction with trichloroacetonitrile, either in situ or in a separate step, and this intermediate undergoes clean enantioselective SN2′ substitution with a variety of carboxylic acids in the presence of the palladium(II) catalyst (Rp,S)-di-μ -acetatobis[(η5-2-(2'-(4'-methylethyl)oxazolinyl)cyclopentadienyl,1-C,3'-N)(η4-tetraphenylcyclobutadiene)cobalt]dipalladium, (Rp,S)-[COP-OAc]2 or its enantiomer. The scope and limitations of this useful catalytic asymmetric allylic esterification are defined. PMID:15740118

  15. Development of the aza-crown ether metal complexes as artificial hydrolase.

    PubMed

    Yu, Lan; Li, Fang-zhen; Wu, Jiao-yi; Xie, Jia-qing; Li, Shuo

    2016-01-01

    Hydrolases play a crucial role in the biochemical process, which can catalyze the hydrolysis of various compounds like carboxylic esters, phosphoesters, amides, nucleic acids, peptides, and so on. The design of artificial hydrolases has attracted extensive attention due to their scientific significance and potential applications in the field of gene medicine and molecular biology. Numerous macrocyclic metal complexes have been used as artificial hydrolase in the catalytic hydrolysis of the organic substrate. Aza-crown ether for this comment is a special class of the macrocyclic ligand containing both the nitrogen atoms and oxygen atoms in the ring. The studies showed that the aza-crown complexes exhibited high activity of hydrolytic enzyme. However, the aza-crown ether metal complex as artificial hydrolase is still very limited because of its difficulty in synthesis. This review summarizes the development of the aza-crown ether metal complexes as the artificial hydrolase, including the synthesis and catalysis of the transition metal complexes and lanthanide metal complexes of aza-crown ethers. The purpose of this review is to highlight: (1) the relationship between the structure and hydrolytic activity of synthetic hydrolase; (2) the synergistic effect of metal sites and ligands in the course of organic compound hydrolysis; and (3) the design strategies of the aza-crown ethers as hydrolase. PMID:26460062

  16. Biodegradation of the gasoline oxygenates methyl tert-butyl ether, ethyl tert-butyl ether, and tert-amyl methyl ether by propane-oxidizing bacteria.

    PubMed Central

    Steffan, R J; McClay, K; Vainberg, S; Condee, C W; Zhang, D

    1997-01-01

    Several propane-oxidizing bacteria were tested for their ability to degrade gasoline oxygenates, including methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-amyl methyl ether (TAME). Both a laboratory strain and natural isolates were able to degrade each compound after growth on propane. When propane-grown strain ENV425 was incubated with 20 mg of uniformly labeled [14C]MTBE per liter, the strain converted > 60% of the added MTBE to 14CO2 in < 30 h. The initial oxidation of MTBE and ETBE resulted in the production of nearly stoichiometric amounts of tert-butyl alcohol (TBA), while the initial oxidation of TAME resulted in the production of tert-amyl alcohol. The methoxy methyl group of MTBE was oxidized to formaldehyde and ultimately to CO2. TBA was further oxidized to 2-methyl-2-hydroxy-1-propanol and then 2-hydroxy isobutyric acid; however, neither of these degradation products was an effective growth substrate for the propane oxidizers. Analysis of cell extracts of ENV425 and experiments with enzyme inhibitors implicated a soluble P-450 enzyme in the oxidation of both MTBE and TBA. MTBE was oxidized to TBA by camphor-grown Pseudomonas putida CAM, which produces the well-characterized P-450cam, but not by Rhodococcus rhodochrous 116, which produces two P-450 enzymes. Rates of MTBE degradation by propane-oxidizing strains ranged from 3.9 to 9.2 nmol/min/mg of cell protein at 28 degrees C, whereas TBA was oxidized at a rate of only 1.8 to 2.4 nmol/min/mg of cell protein at the same temperature. PMID:9361407

  17. 40 CFR 721.3380 - Anilino ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Anilino ether. 721.3380 Section 721... Anilino ether. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as anilino ether (P-83-910) is subject to reporting under this section...

  18. 40 CFR 721.3364 - Aliphatic ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aliphatic ether. 721.3364 Section 721... Aliphatic ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aliphatic ether (PMN P-93-1381) is subject to reporting under...

  19. 40 CFR 721.3364 - Aliphatic ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aliphatic ether. 721.3364 Section 721... Aliphatic ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an aliphatic ether (PMN P-93-1381) is subject to reporting under...

  20. 40 CFR 721.3374 - Alkylenediolalkyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylenediolalkyl ether. 721.3374... Substances § 721.3374 Alkylenediolalkyl ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an alkylenediolalkyl ether (PMN P-93-362) is subject...

  1. 40 CFR 721.3437 - Dialkyl ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Dialkyl ether. 721.3437 Section 721... Dialkyl ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as dialkyl ether (PMN P-93-1308) is subject to reporting under this...

  2. 40 CFR 721.3374 - Alkylenediolalkyl ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylenediolalkyl ether. 721.3374... Substances § 721.3374 Alkylenediolalkyl ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an alkylenediolalkyl ether (PMN P-93-362) is subject...

  3. 40 CFR 721.3437 - Dialkyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dialkyl ether. 721.3437 Section 721... Dialkyl ether. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as dialkyl ether (PMN P-93-1308) is subject to reporting under this...

  4. 21 CFR 868.5420 - Ether hook.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ether hook. 868.5420 Section 868.5420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5420 Ether hook. (a) Identification. An ether hook is a...

  5. 21 CFR 868.5420 - Ether hook.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ether hook. 868.5420 Section 868.5420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5420 Ether hook. (a) Identification. An ether hook is a...

  6. 21 CFR 868.5420 - Ether hook.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ether hook. 868.5420 Section 868.5420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5420 Ether hook. (a) Identification. An ether hook is a...

  7. 21 CFR 868.5420 - Ether hook.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ether hook. 868.5420 Section 868.5420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5420 Ether hook. (a) Identification. An ether hook is a...

  8. 21 CFR 868.5420 - Ether hook.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ether hook. 868.5420 Section 868.5420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5420 Ether hook. (a) Identification. An ether hook is a...

  9. New lipophilic tyrosyl esters. Comparative antioxidant evaluation with hydroxytyrosyl esters.

    PubMed

    Mateos, Raquel; Trujillo, Mariana; Pereira-Caro, Gema; Madrona, Andrés; Cert, Arturo; Espartero, José Luis

    2008-11-26

    New lipophilic esters of tyrosol, a naturally occurring phenol with interesting biological properties, have been synthesized in good yields by a chemoselective procedure, using lipase from Candida antarctica or p-toluenesulfonic acid as catalysts. Their antioxidant activities have been evaluated by the Rancimat test in lipophilic food matrices, as well as by FRAP and ABTS assays in methanolic solutions, and compared with those of previously synthesized hydroxytyrosyl esters. Free tyrosol, hydroxytyrosol, butylhydroxytoluene, and alpha-tocopherol were used as standards. All methods used for the antioxidant activity evaluation emphasized the high influence of the ortho-diphenolic structure on the antioxidant capacity, tyrosol and its derivatives being less active than hydroxytyrosol and its analogues and even less than BHT and alpha-tocopherol. In addition, the Rancimat test revealed a lower activity for ester derivatives than for their respective reference compounds (HTy or Ty), in agreement with the polar paradox. On the other hand, FRAP and ABTS methods reported an opposite behavior between the synthetic esters and their respective references. Thus, hydroxytyrosyl esters were more active than HTy, whereas tyrosyl esters were less active than Ty. The length and nature of the acyl side chain did not seem to play an important role in the antioxidant activity of either the hydroxytyrosyl or tyrosyl ester series, since no significant differences were observed among them. PMID:18983160

  10. Chiral stationary phase covalently bound with a chiral pseudo-18-crown-6 ether for enantiomer separation of amino compounds using a normal mobile phase.

    PubMed

    Hirose, Keiji; Yongzhu, Jin; Nakamura, Takashi; Nishioka, Ryota; Ueshige, Tetsuro; Tobe, Yoshito

    2005-03-01

    In order to apply the excellent chiral recognition ability of chiral pseudo-18-crown-6 ethers that we developed to chiral separation, we prepared a chiral stationary phase (CSP) by immobilizing a chiral pseudo-18-crown-6-type host on 3-aminopropyl silica gel. A chiral column was prepared by the slurry-packing method in a stainless steel HPLC column. A liquid chromatography system using this CSP combined with the detection by mass spectrometry was used for enantiomer separation of amino compounds. A normal mobile phase can be used on this CSP as opposed to conventional dynamic coating-type CSPs. Enantiomers of 18 common natural amino acids were efficiently separated. The chiral separation observed for amino acid methyl esters, amino alcohols, and lipophilic amines was fair using this HPLC system. In view of the correlation between the enantiomer selectivity observed in chromatography and the complexion in solution, the chiral recognition in host-guest interactions might contribute to this enantiomer separation. PMID:15704196

  11. Characterization of alcohol dehydrogenase 1 and 3 from Neurospora crassa FGSC2489.

    PubMed

    Park, Yong-Cheol; San, Ka-Yiu; Bennett, George N

    2007-08-01

    Alcohol dehydrogenase (ADH) is a key enzyme in the production and utilization of alcohols. Some also catalyze the formation of carboxylate esters from alcohols and aldehydes. The ADH1 and ADH3 genes of Neurospora crassa FGSC2489 were cloned and expressed in recombinant Escherichia coli to investigate their alcohol dehydrogenation and carboxylate ester formation abilities. Homology analysis and sequence alignment of amino acid sequence indicated that ADH1 and ADH3 of N. crassa contained a zinc-binding consensus sequence and a NAD(+)-binding motif and showed 54-75% identity with fungi ADHs. N. crassa ADH1 was expressed in E. coli to give a specific activity of 289 +/- 9 mU/mg using ethanol and NAD(+) as substrate and cofactor, respectively. Corresponding experiments on the expression and activity of ADH3 gave 4 mU/mg of specific activity. N. crassa ADH1 preferred primary alcohols containing C3-C8 carbons to secondary alcohols such as 2-propanol and 2-butanol. N. crassa ADH1 possessed 5.3 mU/mg of specific carboxylate ester-forming activity accumulating 0.4 mM of ethyl acetate in 18 h. Substrate specificity of various linear alcohols and aldehydes indicated that short chain-length alcohols and aldehydes were good substrates for carboxylate ester production. N. crassa ADH1 was a primary alcohol dehydrogenase using cofactor NAD(+) preferably and possessed carboxylate ester-forming activity with short chain alcohols and aldehydes. PMID:17516063

  12. Lacinilene C 7-methyl ether

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lacinilene C 7-methyl ether is an antimicrobial compound produced by the cotton plant in response to attack by pathogens. For the first time, we now report the crystal structure of this compound. This may prove useful in studies on the interaction of the compound with pathogenic fungal cells....

  13. Desoxyhemigossypol-6-methyl-ether

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desoxyhemigossypol-6-methyl ether is an antimicrobial compound produced by the cotton plant in response to attack by pathogens. For the first time, we now report the crystal structure of this compound. This may prove useful in studies on the interaction of the compound with pathogenic fungal cells...

  14. Bis(chloromethyl)ether (BCME)

    Integrated Risk Information System (IRIS)

    Bis ( chloromethyl ) ether ( BCME ) ; CASRN 542 - 88 - 1 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 f

  15. 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

  16. Bis(chloroethyl)ether (BCEE)

    Integrated Risk Information System (IRIS)

    Bis ( chloroethyl ) ether ( BCEE ) ; CASRN 111 - 44 - 4 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

  17. p,p\\'-Dibromodiphenyl ether

    Integrated Risk Information System (IRIS)

    p , p ' - Dibromodiphenyl ether ; CASRN 2050 - 47 - 7 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

  18. In vitro enhancement of lactate esters on the percutaneous penetration of drugs with different lipophilicity.

    PubMed

    Zhang, Jianhua; Liu, Mei; Jin, Hongjian; Deng, Liandong; Xing, Jinfeng; Dong, Anjie

    2010-06-01

    Lactate esters are widely used as food additives, perfume materials, medicine additives, and personal care products. The objective of this work was to investigate the effect of a series of lactate esters as penetration enhancers on the in vitro skin permeation of four drugs with different physicochemical properties, including ibuprofen, salicylic acid, dexamethasone and 5-fluorouracil. The saturated donor solutions of the evaluated drugs in propylene glycol were used in order to keep a constant driving force with maximum thermodynamic activity. The permeability coefficient (K(p)), skin concentration of drugs (SC), and lag time (T), as well as the enhancement ratios for K(p) and SC were recorded. All results indicated that lactate esters can exert a significant influence on the transdermal delivery of the model drugs and there is a structure-activity relationship between the tested lactate esters and their enhancement effects. The results also suggested that the lactate esters with the chain length of fatty alcohol moieties of 10-12 are more effective enhancers. Furthermore, the enhancement effect of lactate esters increases with a decrease of the drug lipophilicity, which suggests that they may be more efficient at enhancing the penetration of hydrophilic drugs than lipophilic drugs. The influence of the concentration of lactate esters was evaluated and the optimal concentration is in the range of 5-10 wt.%. In sum, lactate esters as a penetration enhancer for some drugs are of interest for transdermal administration when the safety of penetration enhancers is a prime consideration. PMID:20496018

  19. Alcoholism and Alcohol Abuse

    MedlinePlus

    ... increase the risk of certain cancers. It can cause damage to the liver, brain, and other organs. Drinking during pregnancy can harm your baby. Alcohol also increases the risk of death from car crashes, injuries, homicide, and suicide. If you want to stop drinking, there is ...

  20. Synthesis of oleyl oleate wax esters in Arabidopsis thaliana and Camelina sativa seed oil.

    PubMed

    Iven, Tim; Hornung, Ellen; Heilmann, Mareike; Feussner, Ivo

    2016-01-01

    Seed oil composed of wax esters with long-chain monoenoic acyl moieties represents a high-value commodity for industry. Such plant-derived sperm oil-like liquid wax esters are biodegradable and can have excellent properties for lubrication. In addition, wax ester oil may represent a superior substrate for biodiesel production. In this study, we demonstrate that the low-input oil seed crop Camelina sativa can serve as a biotechnological platform for environmentally benign wax ester production. Two biosynthetic steps catalysed by a fatty alcohol-forming acyl-CoA reductase (FAR) and a wax ester synthase (WS) are sufficient to achieve wax ester accumulation from acyl-CoA substrates. To produce plant-derived sperm oil-like liquid wax esters, the WS from Mus musculus (MmWS) or Simmondsia chinensis (ScWS) were expressed in combination with the FAR from Mus musculus (MmFAR1) or Marinobacter aquaeolei (MaFAR) in seeds of Arabidopsis thaliana and Camelina sativa. The three analysed enzyme combinations Oleo3:mCherry:MmFAR1∆c/Oleo3:EYFP:MmWS, Oleo3:mCherry:MmFAR1∆c/ScWS and MaFAR/ScWS showed differences in the wax ester molecular species profiles and overall biosynthetic performance. By expressing MaFAR/ScWS in Arabidopsis or Camelina up to 59% or 21% of the seed oil TAGs were replaced by wax esters, respectively. This combination also yielded wax ester molecular species with highest content of monounsaturated acyl moieties. Expression of the enzyme combinations in the Arabidopsis fae1 fad2 mutant background high in oleic acid resulted in wax ester accumulation enriched in oleyl oleate (18:1/18:1 > 60%), suggesting that similar values may be obtained with a Camelina high oleic acid line. PMID:25912558

  1. Method for determination of methyl tert-butyl ether and its degradation products in water

    USGS Publications Warehouse

    Church, C.D.; Isabelle, L.M.; Pankow, J.F.; Rose, D.L.; Tratnyek, P.G.

    1997-01-01

    An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method can also give simultaneous identification of polar compounds that might occur as degradation products of gasoline oxygenates, such as TBA, TBF, TAA, methyl acetate, and acetone. When the method was applied to effluent from a column microcosm prepared with core material from an urban site in New Jersey, conversion of MTBE to TBA was observed after a lag period of 35 days. However, to date, analyses of water samples from six field sites using the DAI-GC/MS method have not produced evidence for the expected products of in situ degradation of MTBE.An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method

  2. High octane ethers from synthesis gas-derived alcohols

    SciTech Connect

    Klier, K.; Herman, R.G.; Feeley, O.C.; Johansson, M.A.

    1992-10-01

    Catalytic testing of inorganic catalysts was continued with the highly active sulfate-modified zirconia catalyst prepared here. Using isobutanol as the only reactant over this catalyst, it was demonstrated that high conversion and selectivity to isobutene was achieved at 175[degrees]C. In addition, the high selectivity to isobutene, i.e. 79--86 mol%, was maintained at higher space velocities and higher temperatures. A high productivity of 11.35 mol isobutene was achieved at 225[degrees]C. Utilizing a methanol/isobutanol = 2/1 molar ratio reactant mixture over the ZrO[sub 2]/SO[sub 4][sup 2[minus

  3. Synthesis and Enantiomeric Recognition Studies of Optically Active Pyridino-Crown Ethers Containing an Anthracene Fluorophore Unit.

    PubMed

    Szemenyei, Balázs; Móczár, Ildikó; Pál, Dávid; Kocsis, Ivett; Baranyai, Péter; Huszthy, Péter

    2016-07-01

    Novel enantiopure pyridino-18-crown-6 ether-based sensor molecules containing an anthracene fluorophore unit were synthesized. Their enantiomeric recognition abilities toward the enantiomers of 1-phenylethylamine hydrogen perchlorate (PhEt), 1-(1-naphthyl)ethylamine hydrogen perchlorate (NapEt), phenylglycine methyl ester hydrogen perchlorate (PhgOMe), and phenylalanine methyl ester hydrogen perchlorate (PheOMe) were examined in acetonitrile using fluorescence spectroscopy. The sensor molecules showed appreciable enantiomeric recognition toward the enantiomers of NapEt, PhEt, and PhgOMe. The highest enantioselectivity was found in the case of crown ether containing isobutyl groups in the macroring and the enantiomers of NapEt. Chirality 28:562-568, 2016. © 2016 Wiley Periodicals, Inc. PMID:27349957

  4. Functional Characterization of Enzymes Forming Volatile Esters from Strawberry and Banana[w

    PubMed Central

    Beekwilder, Jules; Alvarez-Huerta, Mayte; Neef, Evert; Verstappen, Francel W.A.; Bouwmeester, Harro J.; Aharoni, Asaph

    2004-01-01

    Volatile esters are flavor components of the majority of fruits. The last step in their biosynthesis is catalyzed by alcohol acyltransferases (AATs), which link alcohols to acyl moieties. Full-length cDNAs putatively encoding AATs were isolated from fruit of wild strawberry (Fragaria vesca) and banana (Musa sapientum) and compared to the previously isolated SAAT gene from the cultivated strawberry (Fragaria × ananassa). The potential role of these enzymes in fruit flavor formation was assessed. To this end, recombinant enzymes were produced in Escherichia coli, and their activities were analyzed for a variety of alcohol and acyl-CoA substrates. When the results of these activity assays were compared to a phylogenetic analysis of the various members of the acyltransferase family, it was clear that substrate preference could not be predicted on the basis of sequence similarity. In addition, the substrate preference of recombinant enzymes was not necessarily reflected in the representation of esters in the corresponding fruit volatile profiles. This suggests that the specific profile of a given fruit species is to a significant extent determined by the supply of precursors. To study the in planta activity of an alcohol acyltransferase and to assess the potential for metabolic engineering of ester production, we generated transgenic petunia (Petunia hybrida) plants overexpressing the SAAT gene. While the expression of SAAT and the activity of the corresponding enzyme were readily detected in transgenic plants, the volatile profile was found to be unaltered. Feeding of isoamyl alcohol to explants of transgenic lines resulted in the emission of the corresponding acetyl ester. This confirmed that the availability of alcohol substrates is an important parameter to consider when engineering volatile ester formation in plants. PMID:15326278

  5. Alcohol Calorie Calculator

    MedlinePlus

    ... Alcohol Calorie Calculator Weekly Total 0 Calories Alcohol Calorie Calculator Find out the number of beer and ... Calories College Alcohol Policies Interactive Body Calculators Alcohol Calorie Calculator Alcohol Cost Calculator Alcohol BAC Calculator Alcohol ...

  6. A new alternative to expandable pedicle screws: Expandable poly-ether-ether-ketone shell.

    PubMed

    Demir, Teyfik

    2015-05-01

    Screw pullout is a very common problem in the fixation of sacrum with pedicle screws. The principal cause of this problem is that the cyclic micro motions in the fixation of sacrum are higher than the other regions of the vertebrae that limit the osteo-integration between bone and screw. In addition to that, the bone quality is very poor at sacrum region. This study investigated a possible solution to the pullout problem without the expandable screws' handicaps. Newly designed poly-ether-ether-ketone expandable shell and classical pedicle screws were biomechanically compared. Torsion test, pullout tests, fatigue tests, flexion/extension moment test, axial gripping capacity tests and torsional gripping capacity tests were conducted in accordance with ASTM F543, F1798 and F1717. Standard polyurethane foam and calf vertebrae were used as embedding medium for pullout tests. Classical pedicle screw pullout load on polyurethane foam was 564.8 N compared to the failure load for calf vertebrae's 1264 N. Under the same test conditions, expandable poly-ether-ether-ketone shell system's pullout loads from polyurethane foam and calf vertebrae were 1196.3 and 1890 N, respectively. The pullout values for expandable poly-ether-ether-ketone shell were 33% and 53% higher than classical pedicle screw on polyurethane foam and calf vertebrae, respectively. The expandable poly-ether-ether-ketone shell exhibited endurance on its 90% of yield load. Contrary to poly-ether-ether-ketone shell, classical pedicle screw exhibited endurance on 70% of its yield load. Expandable poly-ether-ether-ketone shell exhibited much higher pullout performance than classical pedicle screw. Fatigue performance of expandable poly-ether-ether-ketone shell is also higher than classical pedicle screw due to damping the micro motion capacity of the poly-ether-ether-ketone. Expandable poly-ether-ether-ketone shell is a safe alternative to all other expandable pedicle screw systems on mechanical perspective

  7. Synthesis and characterization of ester and amide derivatives of titanium(IV) carboxymethylphosphonate

    SciTech Connect

    Melánová, Klára; Beneš, Ludvík; Trchová, Miroslava; Svoboda, Jan; Zima, Vítězslav

    2013-06-15

    A set of layered ester and amide derivatives of titanium(IV) carboxymethylphosphonate was prepared by solvothermal treatment of amorphous titanium(IV) carboxymethylphosphonate with corresponding 1-alkanols, 1,ω-alkanediols, 1-aminoalkanes, 1,ω-diaminoalkanes and 1,ω-amino alcohols and characterized by powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Whereas alkyl chains with one functional group form bilayers tilted to the layers, 1,ω-diaminoalkanes and most of 1,ω-alkanediols form bridges connecting the adjacent layers. In the case of amino alcohols, the alkyl chains form bilayer and either hydroxyl or amino group is used for bonding. This simple method for the synthesis of ester and amide derivatives does not require preparation of acid chloride derivative as a precursor or pre-intercalation with alkylamines and can be used also for the preparation of ester and amide derivatives of titanium carboxyethylphosphonate and zirconium carboxymethylphosphonate. - Graphical abstract: Ester and amide derivatives of layered titanium carboxymethylphosphonate were prepared by solvothermal treatment of amorphous solid with alkanol or alkylamine. - Highlights: • Ester and amide derivatives of titanium carboxymethylphosphonate. • Solvothermal treatment of amorphous solid with alkanol or alkylamine. • Ester and amide formation confirmed by IR spectroscopy.

  8. Acrylic esters in radiation polymerization

    SciTech Connect

    Fomina, N.V.; Khoromskaya, V.A.; Shiryaeva, G.V.

    1988-03-01

    The radiation behavior of (meth)acrylic esters of varying structure was studied. It was shown that in radiation polymerization, in contrast to thermal polymerization, the structure of the ester part can significantly affect the reaction rate and capacity for polymerization in the presence of oxygen. The experimental data are explained from the point of view of consideration of nonvalence effects of the substitutent on the reactivity of the double bond.

  9. Liquid Densities of Fluorinated Ethers

    NASA Astrophysics Data System (ADS)

    Nakazawa, Noriaki; Sako, Takeshi; Nakane, Takashi; Sekiya, Akira; Kawamura, Mitsutaka; Sato, Masahito; Mochizuki, Yuji; Takada, Naoto; Yasumoto, Masahiko

    The liquid densities of thirteen fluorinated ethers which are expected as promising candidates of CFC alternatives were measured at temperatures from 278 K to 323 K and atmospheric pressure. The fluorinated ethers used in this study are 1-difluoromethoxy-1,1, 2- trifluoroethane, 1-methoxy-1, 1,2,2-tetrafluoroethane, 1-methoxy-2,2 ,3 ,3- tetrafluoropropane, 1-methoxy-1-trifluoromethy1-2,2 ,2- trifluoroethane, 1-methoxy-1,1,2,2, 3-hexafluoropropane,1-difluoromethoxy-2,2, 3, 3 -tetrafluoropropane, 1-methoxy-heptafluoropropane,1-difluoromethoxy-2, 2, 3, 3, 3-pentafluoropropane, 1- (2, 2, 2-trifruoroethoxy) -1, 1, 2,2-tetrafluoroethane, 1-pentafluoroethoxy-1, 1, 2, 2-tetrafluoroethane,2-trifluoromethoxy-1, 1, 1,2-tetrafluorobutane, 1-proxynonafluorobutane, and 1-ethoxy-undecafluoropentane. The liquid density has been measured by the vibrating tube densitometer (ANTON PARR, DMA 602) within an error of 0.07%. The liquid densities decrease monotonically with increase of temperature.

  10. Influence of the brewing process on furfuryl ethyl ether formation during beer aging.

    PubMed

    Vanderhaegen, Bart; Neven, Hedwig; Verstrepen, Kevin J; Delvaux, Freddy R; Verachtert, Hubert; Derdelinckx, Guy

    2004-11-01

    In beer, the development of a solvent-like stale flavor is associated with the formation of furfuryl ethyl ether. The synthesis rate of this important flavor compound is proportional to the concentration of furfuryl alcohol in beer. This study shows that furfuryl alcohol in beer is mainly formed by Maillard reactions initiated during wort boiling and malt production. A mechanism for its formation from alpha-(1,4)-oligoglucans and amino acids in wort and beer is proposed. During wort boiling, a quadratic relationship was found between the wort extract concentration, on the one hand, and the increase of furfuryl alcohol and furfural, on the other. The reduction of furfural by yeast during fermentation further increases the furfuryl alcohol content. In pale beers, the furfuryl alcohol concentration is essentially determined by the thermal load on wort during brewing operations. In dark beers, a considerable fraction of furfuryl alcohol may, however, come from the dark malts used. These results lead to important practical conclusions concerning the control over furfuryl ethyl ether in beer. PMID:15506813

  11. Measuring exposures to glycol ethers.

    PubMed

    Clapp, D E; Zaebst, D D; Herrick, R F

    1984-08-01

    In 1981, NIOSH began investigating the potential reproductive health effects resulting from exposures to a class of organic solvents known generically as glycol ethers (GE). This research was begun as a result of the NIOSH criteria document development program which revealed little data available on the health effects of glycol ether exposure. Toxicologic research was begun by NIOSH and other researchers which suggested substantial reproductive effects in animals. These animal data motivated a study of human exposures in the occupational setting. In 1981 and 1982 NIOSH conducted several walk-through surveys which included preliminary measurements of exposures in a variety of industries including painting trades, coal mining, production blending and distribution facilities, aircraft fueling, and communications equipment repair facilities. The human exposure data from these surveys is summarized in this paper with most results well below 1 parts per million (ppm) and only a few values approaching 10 ppm. Blood samples were collected at one site resulting in GE concentrations below the limit of detection. Exposures to airborne glycol ethers, in the industries investigated during the collection of this data, revealed several problems in reliably sampling GE at low concentrations. It became apparent, from the data and observations of work practices, that air monitoring alone provided an inadequate index of GE exposure. Further field studies of exposure to GE are anticipated, pending location of additional groups of exposed workers and development of more reliable methods for characterizing exposure, especially biological monitoring. PMID:6499824

  12. [Analysis of constituents of ester-type gum bases used as natural food additives].

    PubMed

    Tada, Atsuko; Masuda, Aino; Sugimoto, Naoki; Yamagata, Kazuo; Yamazaki, Takeshi; Tanamoto, Kenichi

    2007-12-01

    The differences in the constituents of ten ester-type gum bases used as natural food additives in Japan (urushi wax, carnauba wax, candelilla wax, rice bran wax, shellac wax, jojoba wax, bees wax, Japan wax, montan wax, and lanolin) were investigated. Several kinds of gum bases showed characteristic TLC patterns of lipids. In addition, compositions of fatty acid and alcohol moieties of esters in the gum bases were analyzed by GC/MS after methanolysis and hydrolysis, respectively. The results indicated that the varieties of fatty acids and alcohols and their compositions were characteristic for each gum base. These results will be useful for identification and discrimination of the ester-type gum bases. PMID:18203503

  13. New Ruthenium Complexes Based on Tetradentate Bipyridine Ligands for Catalytic Hydrogenation of Esters.

    PubMed

    Wang, Fangyuan; Tan, Xuefeng; Lv, Hui; Zhang, Xumu

    2016-08-01

    New bipyridinemethanamine-containing tetradentate ligands and their corresponding ruthenium complexes have been synthesized. The synthesized complexes performed well in the hydrogenation of a variety of esters with high efficiency (TON up to 9700) giving alcohols in good yields. PMID:27385062

  14. OPTIMIZATION OF ALKYL ESTER PRODUCTION FROM GREASE USING A PHYLLOSILICATE SOL-GEL IMMOBILIZED LIPASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple alkyl ester derivatives of restaurant grease were prepared using a lipase from Pseudomonas cepacia immobilized within a phyllosilicate sol-gel matrix as biocatalyst. Alcoholysis reactions of grease were carried out in solvent-free media using a one step addition of alcohol to reaction mixtur...

  15. Propyl alcohol

    MedlinePlus

    Rubbing alcohol Alcohol swabs Skin and hair products Nail polish remover Note: This list may not be all ... number will let you talk to experts in poisoning. They will give you further instructions. This is ...

  16. Alcoholic hallucinosis.

    PubMed

    Bhat, Pookala S; Ryali, Vssr; Srivastava, Kalpana; Kumar, Shashi R; Prakash, Jyoti; Singal, Ankit

    2012-07-01

    Alcoholic hallucinosis is a rare complication of chronic alcohol abuse characterized by predominantly auditory hallucinations that occur either during or after a period of heavy alcohol consumption. Bleuler (1916) termed the condition as alcohol hallucinosis and differentiated it from Delirium Tremens. Usually it presents with acoustic verbal hallucinations, delusions and mood disturbances arising in clear consciousness and sometimes may progress to a chronic form mimicking schizophrenia. One such case with multimodal hallucinations in a Defence Service Corps soldier is presented here. PMID:24250051

  17. Alcohol Abuse

    ERIC Educational Resources Information Center

    O'Farrell, Timothy J.; Fals-Stewart, William

    2003-01-01

    We received 38 controlled studies of marital and family therapy (MFT) in alcoholism treatment. We conclude that, when the alcoholic is unwilling to seek help, MFT is effective in helping the family cope better and motivating alcoholics to enter treatment. Specifically, (a) Al-Anon facilitation and referral help family members cope better; (b)…

  18. Tartaric Acid-based Amphiphilic Macromolecules with Ether Linkages Exhibit Enhanced Repression of Oxidized Low Density Lipoprotein Uptake

    PubMed Central

    Abdelhamid, Dalia; Zhang, Yingue; Lewis, Daniel R.; Moghe, Prabhas V.; Welsh, William J.; Uhrich, Kathryn E.

    2015-01-01

    Cardiovascular disease initiates with the atherogenic cascade of scavenger receptor- (SR-) mediated oxidized low-density lipoprotein (oxLDL) uptake. Resulting foam cell formation leads to lipid-rich lesions within arteries. We designed amphiphilic macromolecules (AMs) to inhibit these processes by competitively blocking oxLDL uptake via SRs, potentially arresting atherosclerotic development. In this study, we investigated the impact of replacing ester linkages with ether linkages in the AM hydrophobic domain. We hypothesized that ether linkages would impart flexibility for orientation to improve binding to SR binding pockets, enhancing anti-atherogenic activity. A series of tartaric acid-based AMs with varying hydrophobic chain lengths and conjugation chemistries were synthesized, characterized, and evaluated for bioactivity. 3-D conformations of AMs in aqueous conditions may have significant effects on anti-atherogenic potency and were simulated by molecular modeling. Notably, ether-linked AMs exhibited significantly higher levels of inhibition of oxLDL uptake than their corresponding ester analogues, indicating a dominant effect of linkage flexibility on pharmacological activity. The degradation stability was also enhanced for ether-linked AMs. These studies further suggested that alkyl chain length (i.e., relative hydrophobicity), conformation (i.e., orientation), and chemical stability play a critical role in modulating oxLDL uptake, and guide the design of innovative cardiovascular therapies. PMID:25890704

  19. Method for the determination of natural ester-type gum bases used as food additives via direct analysis of their constituent wax esters using high-temperature GC/MS

    PubMed Central

    Tada, Atsuko; Ishizuki, Kyoko; Yamazaki, Takeshi; Sugimoto, Naoki; Akiyama, Hiroshi

    2014-01-01

    Natural ester-type gum bases, which are used worldwide as food additives, mainly consist of wax esters composed of long-chain fatty acids and long-chain fatty alcohols. There are many varieties of ester-type gum bases, and thus a useful method for their discrimination is needed in order to establish official specifications and manage their quality control. Herein is reported a rapid and simple method for the analysis of different ester-type gum bases used as food additives by high-temperature gas chromatography/mass spectrometry (GC/MS). With this method, the constituent wax esters in ester-type gum bases can be detected without hydrolysis and derivatization. The method was applied to the determination of 10 types of gum bases, including beeswax, carnauba wax, lanolin, and jojoba wax, and it was demonstrated that the gum bases derived from identical origins have specific and characteristic total ion chromatogram (TIC) patterns and ester compositions. Food additive gum bases were thus distinguished from one another based on their TIC patterns and then more clearly discriminated using simultaneous monitoring of the fragment ions corresponding to the fatty acid moieties of the individual molecular species of the wax esters. This direct high-temperature GC/MS method was shown to be very useful for the rapid and simple discrimination of varieties of ester-type gum bases used as food additives. PMID:25473499

  20. Method for the determination of natural ester-type gum bases used as food additives via direct analysis of their constituent wax esters using high-temperature GC/MS.

    PubMed

    Tada, Atsuko; Ishizuki, Kyoko; Yamazaki, Takeshi; Sugimoto, Naoki; Akiyama, Hiroshi

    2014-07-01

    Natural ester-type gum bases, which are used worldwide as food additives, mainly consist of wax esters composed of long-chain fatty acids and long-chain fatty alcohols. There are many varieties of ester-type gum bases, and thus a useful method for their discrimination is needed in order to establish official specifications and manage their quality control. Herein is reported a rapid and simple method for the analysis of different ester-type gum bases used as food additives by high-temperature gas chromatography/mass spectrometry (GC/MS). With this method, the constituent wax esters in ester-type gum bases can be detected without hydrolysis and derivatization. The method was applied to the determination of 10 types of gum bases, including beeswax, carnauba wax, lanolin, and jojoba wax, and it was demonstrated that the gum bases derived from identical origins have specific and characteristic total ion chromatogram (TIC) patterns and ester compositions. Food additive gum bases were thus distinguished from one another based on their TIC patterns and then more clearly discriminated using simultaneous monitoring of the fragment ions corresponding to the fatty acid moieties of the individual molecular species of the wax esters. This direct high-temperature GC/MS method was shown to be very useful for the rapid and simple discrimination of varieties of ester-type gum bases used as food additives. PMID:25473499

  1. Analysis of phosphate esters in plant material

    PubMed Central

    Isherwood, F. A.; Barrett, F. C.

    1967-01-01

    1. A critical study was made of the quantitative extraction of nucleotide and sugar phosphates from plant tissue by either boiling aqueous ethanol or cold trichloroacetic acid. The effect of the extraction technique on the inactivation of the enzymes in the plant tissue and the possibility of adsorption of the phosphate esters on the cell wall were especially considered. 2. In the recommended method the plant tissue was frozen in liquid nitrogen, ground to a powder and then blended with cold aqueous trichloroacetic acid containing 8-hydroxyquinoline to prevent adsorption. 3. The extract contained large amounts of trichloroacetic acid, cations, chloride, sugars, amino acids, hydroxy organic acids, phytic acid, orthophosphoric acid and high-molecular-weight material including some phosphorus-containing compounds. All of these were removed as they were liable to interfere with the chromatographic or enzymic assay of the individual nucleotide or sugar phosphates. 4. The procedure was as follows: the last traces of trichloroacetic acid were extracted with ether after the solution had been passed through a column of Dowex AG 50 in the hydrogen form to remove all cations. High-molecular-weight compounds were removed by ultrafiltration and low-molecular-weight solutes by a two-stage chromatography on cellulose columns with organic solvents. In the first stage, sugars, amino acids, chloride and phytic acid were separated by using a basic solvent (propan-1-ol–water–aqueous ammonia) and, in the second stage, the organic acids and orthophosphoric acid were separated by using an acidic solvent (di-isopropyl ether–formic acid–2-methylpropan-2-ol–water). The final solution of nucleotide and sugar phosphates was substantially free from other solutes and was suitable for the detection of individual phosphate esters by either chromatography or enzymic assay. 5. The recovery of d-glucose 6-phosphate or adenosine 5′-triphosphate added to a trichloroacetic acid extract

  2. Anti-friction properties of ester additives during hot rolling of aluminum{copyright}

    SciTech Connect

    Januszkiewicz, K.R.; Bekmesian, G.; Heenan, D.F.

    1995-08-01

    Heavy esters of polyhydric alcohols, such as glycerol and synthetic polyols, are commonly used as additives in aluminum hot rolling lubricants. The presence of several hydroxyl groups allows a varying degree of esterification leading to the formation of full and partial esters. These esters are rarely separated from the main additive, and thus may be present in the finished rolling lubricant, affecting its anti-friction properties. The objective of this work was to examine the anti-friction properties of these potential ester contaminants during rolling on a laboratory hot rolling mill. Two lubricant application methods were examined; as emulsion and direct (neat oil) application. The anti-friction properties of additives were found to depend on their chemical structure and the lubricant applications method. In emulsified oils, partial esters of glycerol were found to greatly reduce friction in comparison to triglycerides, while the partial esters of synthetic polyols exhibited only a weak anti-friction effect. There was no frictional advantage observed which could be associated with using the partial esters in direct application mode. Moreover, under these conditions, the anti-friction properties of the completely esterified synthetic polyols were significantly lower than those of triglycerides, while in emulsions they were comparable. 11 refs., 7 figs., 3 tabs.

  3. Synthesis of novel naphthoquinone aliphatic amides and esters and their anticancer evaluation.

    PubMed

    Kongkathip, Boonsong; Akkarasamiyo, Sunisa; Hasitapan, Komkrit; Sittikul, Pichamon; Boonyalai, Nonlawat; Kongkathip, Ngampong

    2013-02-01

    Fourteen new naphthoquinone aliphatic amides and seventeen naphthoquinone aliphatic esters were synthesized in nine to ten steps from 1-hydroxy-2-naphthoic acid with 9-25% overall yield for the amides, and 16-21% overall yield for the esters. The key step of the amide synthesis is a coupling reaction between amine and various aliphatic acids using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as a coupling agent while for the ester synthesis, DCC/DMAP or CDI was used as the coupling reagent between aliphatic acids and naphthoquinone alcohol. Both naphthoquinone amides and esters were evaluated for their anticancer activity against KB cells. It was found that naphthoquinone aliphatic amides showed stronger anticancer activity than those of the esters when the chains are longer than 7-carbon atoms. The optimum chain of amides is expected to be 16-carbon atoms. In addition, naphthoquinone aliphatic esters with α-methyl on the ester moiety possessed much stronger anticancer activity than the straight chains. Decatenation assay revealed that naphthoquinone amide with 16-carbon atoms chain at 15 μM and 20 μM can completely inhibit hTopoIIα activity while at 10 μM the enzyme activity was moderately inhibited. Molecular docking result also showed the same trend as the cytotoxicity and decatenation assay. PMID:23313636

  4. Crystalline Imide/Arylene Ether Copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.; Hergenrother, Paul M.; Bass, Robert G.

    1991-01-01

    Series of imide/arylene ether block copolymers prepared by using arylene ether blocks to impart low melt viscosity, and imide blocks to provide high strength and other desirable mechanical properties. Work represents extension of LAR-14159 on imide/arylene ether copolymers in form of films, moldings, adhesives, and composite matrices. Copolymers potentially useful in variety of high-temperature aerospace and microelectronic applications.

  5. Aza crown ether compounds as anion receptors

    DOEpatents

    Lee, Hung Sui; Yang, Xiao-Oing; McBreen, James

    1998-08-04

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI.sup.+ ion in alkali metal batteries.

  6. Aza crown ether compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.O.; McBreen, J.

    1998-08-04

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI{sup +} ion in alkali metal batteries. 3 figs.

  7. Photosynthesis involvement in the mechanism of action of diphenyl ether herbicides.

    PubMed

    Ensminger, M P; Hess, F D

    1985-05-01

    Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity. PMID:16664206

  8. Photosynthesis Involvement in the Mechanism of Action of Diphenyl Ether Herbicides 1

    PubMed Central

    Ensminger, Michael P.; Hess, F. Dan

    1985-01-01

    Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity. PMID:16664206

  9. Predicting autoxidation stability of ether- and amide-based electrolyte solvents for Li-air batteries.

    PubMed

    Bryantsev, Vyacheslav S; Faglioni, Francesco

    2012-07-01

    Finding suitable solvents remains one of the most elusive challenges in rechargeable, nonaqueous Li-air battery technology. Although ether and amides are identified as stable classes of aprotic solvents against nucleophilic attack by superoxide, many of them are prone to autoxidation under oxygen atmosphere. In this work, we use density functional theory calculations coupled with an implicit solvent model to investigate the autoxidative stability of ether- and N,N-dialkylamide-based solvents. The change in the activation free energy for the C-H bond cleavage by O(2) is consistent with the extent of peroxide production for each class of solvent. Conversely, the thermodynamic stability alone is not sufficient to account for the observed variation in solvent reactivity toward O(2). A detailed understanding of the factors influencing the autoxidative stability provides several strategies for designing molecules with enhanced air/O(2) stability, comparable or superior to that of structurally related hydrocarbons. The mechanism of superoxide-mediated oxidation of hydroperoxides derived from ethers and amides is presented. The degradation mechanism accounts for the primary decomposition products (esters and carboxylates) observed in the Li-air battery with ether-based electrolytes. The identification of solvents having resistance to autoxidation is critical for the development of rechargeable Li-air batteries with long cycle life. PMID:22681046

  10. Synthesis and fungicidal activities of novel benzothiophene-substituted oxime ether strobilurins.

    PubMed

    Tu, Song; Xie, Ya-Qiang; Gui, Si-Zhe; Ye, Li-Yi; Huang, Zi-Long; Huang, Yi-Bing; Che, Li-Ming

    2014-05-01

    Twenty-one novel benzothiophene-substituted oxime ether strobilurins, which employed a benzothiophene group to stabilise the E-styryl group in Enoxastrobin (an unsaturated oxime strobilurin fungicide developed by Shenyang Research Institute of Chemical Industry, China) were designed and synthesised. The biological assay indicated that most compounds exhibited good or excellent fungicidal activities, especially against Colletotrichum lagenarium and Puccinia sorghi Schw. In addition, methyl 3-methoxypropenoate oxime ethers and N-methoxy-carbamic acid methyl esters exhibited good in vivo fungicidal activities against Erysiphe graminis, Colletotrichum lagenarium and Puccinia sorghi Schw. under the tested concentrations. Notably, (E,E)-methyl 3-methoxy-2-(2-((((6-chloro-1-(1H-benzo[b]thien-2-yl)ethylidene)amino)oxy)methyl)phenyl)propenoate (5E) exhibited more potent in vivo fungicidal activities against nearly all of the tested fungi at a concentration of 0.39 mg/L compared to Enoxastrobin. PMID:24717155

  11. LaRC-ITPI/arylene ether copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.; Working, Dennis C.

    1991-01-01

    As part of an effort to develop high performance structural resins for aerospace applications, work has continued on block copolymers containing imide and arylene ether segments. The arylene ether block used in this study contains a bulky fluorene group in the polymer backbone while the imide block contains an arylene ketone segment similar to that in the arylene ether block and has been named LaRC-ITPI. A series of imide/arylene ether block and segmented copolymers were prepared and characterized. Films were prepared from these copolymers and mechanical properties were measured.

  12. Facts about Alcohol and Alcoholism.

    ERIC Educational Resources Information Center

    Hall, Leonard C.

    Recognition of alcoholism as a treatable illness is a result of public education based on scientific facts. This publication, a digest of a more detailed survey of research about drinking and alcoholism, presents information about alcohol and its effects on individuals and society. It provides facts about the short-term and long-term effects of…

  13. Alcoholic cardiomyopathy

    PubMed Central

    Guzzo-Merello, Gonzalo; Cobo-Marcos, Marta; Gallego-Delgado, Maria; Garcia-Pavia, Pablo

    2014-01-01

    Alcohol is the most frequently consumed toxic substance in the world. Low to moderate daily intake of alcohol has been shown to have beneficial effects on the cardiovascular system. In contrast, exposure to high levels of alcohol for a long period could lead to progressive cardiac dysfunction and heart failure. Cardiac dysfunction associated with chronic and excessive alcohol intake is a specific cardiac disease known as alcoholic cardiomyopathy (ACM). In spite of its clinical importance, data on ACM and how alcohol damages the heart are limited. In this review, we evaluate available evidence linking excessive alcohol consumption with heart failure and dilated cardiomyopathy. Additionally, we discuss the clinical presentation, prognosis and treatment of ACM. PMID:25228956

  14. 75 FR 50926 - 2-propenoic acid, 2-methyl-, C12-16-alkyl esters, telomers with 1-dodecanethiol, polyethylene...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of 2-propenoic acid, 2-methyl-, C12-16- alkyl esters, telomers with 1-dodecanethiol, polyethylene-polypropylene glycol ether with propylene glycol monomethacrylate (1:1), and styrene 2,2'-(1,2-diazenediyl)bis[2-methylbutanenitrile]-initiated, number average molecular weight (in AMU) 4000; when used as an......

  15. Catalytic asymmetric Claisen rearrangement of Gosteli-type allyl vinyl ethers: total synthesis of (-)-9,10-dihydroecklonialactone B.

    PubMed

    Becker, Julia; Butt, Lena; von Kiedrowski, Valeska; Mischler, Elisabeth; Quentin, Florian; Hiersemann, Martin

    2014-04-01

    The enantioselective synthesis of (-)-9,10-dihydroecklonialactone B is described. The catalytic asymmetric Claisen rearrangement of a Gosteli-type allyl vinyl ether was utilized to afford an acyclic α-keto ester building block endowed with functionality amenable to the preparation of the carbocyclic target molecule by suitable postrearrangement transformations: A highly diastereoselective Corey-Bakshi-Shibata reduction of a β-chiral α-keto ester and a reductive homologation of an α-hydroxy ester. A transprotection tactic by a chemoselective intramolecular 6-exo-trig iodoetherification enabled regioselective ring-closing alkene metatheses to afford the 5- as well as the 14-membered ring, however, with mixed success in terms of E/Z selectivity. PMID:24621347

  16. Congenital malformation and maternal occupational exposure to glycol ethers. Occupational Exposure and Congenital Malformations Working Group.

    PubMed

    Cordier, S; Bergeret, A; Goujard, J; Ha, M C; Aymé, S; Bianchi, F; Calzolari, E; De Walle, H E; Knill-Jones, R; Candela, S; Dale, I; Dananché, B; de Vigan, C; Fevotte, J; Kiel, G; Mandereau, L

    1997-07-01

    Glycol ethers are found in a wide range of domestic and industrial products, many of which are used in women's work environments. Motivated by concern about their potential reproductive toxicity, we have evaluated the risk of congenital malformations related to glycol ether exposure during pregnancy as part of a multicenter case-control study, conducted in six regions in Europe. The study comprised 984 cases of major congenital malformations and 1,134 controls matched for place and date of birth. Interviews of the mothers provided information about occupation during pregnancy, sociodemographic variables, and other potential risk factors (medical history, tobacco, alcohol, drugs). A chemist specializing in glycol ethers evaluated exposure during pregnancy, using the job description given by the mother, without knowledge of case or control status. We classified malformations into 22 subgroups. The overall odds ratio (OR) of congenital malformation associated with glycol ether exposure was 1.44 [95% confidence interval (CI) = 1.10-1.90], after adjustment for several potential confounders. The association with exposure to glycol ethers appeared particularly strong in three subgroups: neural tube defects (OR = 1.94; 95% CI = 1.16-3.24), multiple anomalies (OR = 2.00; 95% CI = 1.24-3.23), and cleft lip (OR = 2.03; 95% CI = 1.11-3.73). In this last subgroup, risk, especially of an isolated defect, tended to increase with level of exposure. PMID:9209847

  17. Brown's second alcohol fuel cookbook

    SciTech Connect

    Brown, M.H.

    1981-01-01

    Instructions are given for making and using various types of alcohol fuels in internal combustion engines. The distillation column is treated at some length as well as stripper columns for sugar substances, reflux ratio and proof concentration, condensers, and junkyard steam boilers. Safety features are stressed as well as plant layout. Enzymes for alcohol production and starch fermentation are described as well as commercial enzyme production, continuous fermentation, distillation of crude oil, alcohol production from cellulose (sawdust), and preparation of alcohol fuel and other products (butanol, acetone, ether) without distillation. Production of dry ice (solidified CO/sub 2/) is described. The conversion of carburetor jets in auto engines for different fuel blends, and the use of heat risers and pre-heaters to facilitate engine starting are discussed at length. In an appendix, a patent for production of acetone and alcohol by bacteriological action is included as well as congressional testimony on a hearing dealing with biomass, renewable fuel sources, fuel economy of engines and related topics. (MJJ)

  18. Flow-Induced Crystallization of Poly(ether ether ketone)

    NASA Astrophysics Data System (ADS)

    Nazari, Behzad; Rhoades, Alicyn; Colby, Ralph

    The effects of an interval of shear above the melting temperature Tm on subsequent isothermal crystallization below Tm is reported for the premier engineering thermoplastic, poly(ether ether ketone) (PEEK). The effect of shear on the crystallization rate of PEEK is investigated by means of rheological techniques and differential scanning calorimetry (DSC) under a protocol of imposing shear in a rotational cone and plate rheometer and monitoring crystallization after quenching. The rate of crystallization at 320 °C was not affected by shear for shear rates <7 s-1 at 350 °C, whereas intervals of adequate shear at higher shear rates prior to the quench to 320 °C accelerated crystallization significantly. As the duration of the interval of shear above 7 s-1 is increased, the crystallization time decreases but at each shear rate eventually saturates once the applied specific work exceeds ~120 MPa. The annealing of the flow-induced precursors was also investigated. The nuclei were fairly persistent at temperatures close to 350 °C, however very unstable at temperatures above 375 °C. This suggests that the nanostructures formed under shear might be akin to crystalline lamellae of greater thickness, compared to quiescently crystallized lamellae.

  19. Fiberite 954: cyanate ester systems

    NASA Astrophysics Data System (ADS)

    Almen, G. R.; Mackenzie, P. D.; Malhotra, Vinay; Maskell, R. K.

    1992-09-01

    Cost and weight savings achieved by the use of composites have allowed these materials to displace their metal counterparts in space applications. Epoxy matrix based carbon fiber reinforced composites, such as Fiberite 934, have been used for a number of years. Relative to these systems, cyanate esters offer a number of unique attributes such as excellent hydrophobicity and electrical properties, reduced residual stress and better microcrack resistance, and improved radiation resistance. The significant reduction in water sorption and the low response to uptake make it possible to achieve much improved dimensional stability and reduced outgassing. These features may be used to advantage in electro-optical applications in space. ICI Fiberite has developed cyanate ester based prepreg systems that are penetrating the satellite, military radome and structural aerospace markets. Features of these systems will be presented and the properties of the cyanate ester based prepreg, Fiberite 954- 3, will be compared to those of Fiberite 934.

  20. Retention indices, relative response factors, and mass spectra of trifluoroethyl and heptafluorobutyl esters of carboxylic acids determined by capillary GC/MS

    SciTech Connect

    Yu, S.K.-T.; Vrana, R.P.; Green, J.B.

    1990-11-01

    The GC/MS characteristics of carboxylic acid esters prepared from fluorine-containing alcohols were compared to those of methyl esters. The GC retention of 2,2,2-trifluoroethyl (TFE) esters was less than, and 2,2,3,3,4,4,4-heptafluoro-1-butyl (HFB) esters approximately equivalent to that of methyl esters. The peak shape of both TFE and HFB esters was slightly superior to that of methyl esters. Mass spectra of TFE and HFB aliphatic esters show significantly more intense molecular and key fragment ions than those of methyl esters. Also, owing to their significantly higher molecular weights, TFE or HFB ester molecular ions and most fragment ions of interest occur at significantly higher m/z values than most potential interfering ions. The GC retention indices, relative GC/MS total ion current response factors, and 70 eV electron impact mass spectra of about 70 TFE and 70 HFB carboxylic acid esters are reported. Results from analysis of a TFE/HFB esterified petroleum carboxylic acid concentrate are discussed in detail. 26 refs., 17 figs., 3 tabs.

  1. Prebiotic phosphate ester syntheses in a deep eutectic solvent.

    PubMed

    Gull, Maheen; Zhou, Manshui; Fernández, Facundo M; Pasek, Matthew A

    2014-02-01

    We report a route to synthesize a wide range of organophosphates of biological significance in a deep eutectic solvent (2:1 urea and choline chloride), utilizing various orthophosphate sources. Heating an organic alcohol in the solvent along with a soluble phosphorus source yields phosphorus esters of choline as well as that of the added organic in yields between 15 to 99 %. In addition, phosphite analogs of biological phosphates and peptides were also formed by the simple mixing of reagents and heating at 60-70 °C in the deep eutectic solvent. The presented dehydration reactions are relevant to prebiotic and green chemistry in alternative solvents. PMID:24368625

  2. Overview of Alcohol Consumption

    MedlinePlus

    ... Search Alcohol & Your Health Overview of Alcohol Consumption Alcohol's Effects on the Body Alcohol Use Disorder Fetal Alcohol ... other questions about alcohol. Here’s what we know: Alcohol’s effects vary from person to person, depending on a ...

  3. The EIMS fragmentation mechanisms of the sesquiterpenes corvol ethers A and B, epi-cubebol and isodauc-8-en-11-ol

    PubMed Central

    Rabe, Patrick

    2016-01-01

    Summary Farnesyl diphosphate (FPP) and all fifteen positional isomers of (13C1)FPP were enzymatically converted by the bacterial terpene cyclases corvol ether synthase from Kitasatospora setae, the epi-cubebol synthase from Streptosporangium roseum, and the isodauc-8-en-11-ol synthase from Streptomyces venezuelae. The enzyme products were analysed by GC–MS and GC–QTOF MS2 and the obtained data were used to delineate the EIMS fragmentation mechanisms of the two sesquiterpene ethers corvol ethers A and B, and the sesquiterpene alcohols epi-cubebol and isodauc-8-en-11-ol. PMID:27559388

  4. The EIMS fragmentation mechanisms of the sesquiterpenes corvol ethers A and B, epi-cubebol and isodauc-8-en-11-ol.

    PubMed

    Rabe, Patrick; Dickschat, Jeroen S

    2016-01-01

    Farnesyl diphosphate (FPP) and all fifteen positional isomers of ((13)C1)FPP were enzymatically converted by the bacterial terpene cyclases corvol ether synthase from Kitasatospora setae, the epi-cubebol synthase from Streptosporangium roseum, and the isodauc-8-en-11-ol synthase from Streptomyces venezuelae. The enzyme products were analysed by GC-MS and GC-QTOF MS(2) and the obtained data were used to delineate the EIMS fragmentation mechanisms of the two sesquiterpene ethers corvol ethers A and B, and the sesquiterpene alcohols epi-cubebol and isodauc-8-en-11-ol. PMID:27559388

  5. Serum lipids and acyl group composition of alcoholic patients.

    PubMed

    Sun, G Y; Rush, A; Chin, P C; Gorka, C; Lahiri, S; Wood, W G

    1988-01-01

    The lipid content and acyl group composition of serum from a group of alcoholic patients at a VA Medical Center were compared to control subjects sampled either from University of Missouri personnel or from subjects who were undergoing a preemployment physical examination at the same VA Medical Center. Plasma of alcoholic patients indicated an elevated triacylglycerol level (24-35%) as compared to both control groups. In addition, the acyl groups of triacylglycerols of alcoholic patients showed a markedly lower proportion of 18:2 and a higher proportion of 18:0 and 18:1 as compared to the control groups. The level of phosphatidylcholines in the plasma of alcoholic patients was not different from controls. However, acyl group composition of phosphatidylcholines from alcoholics indicated a lower proportion of 22:6 (n-3) as compared to controls. Although the cholesteryl ester level in serum was higher in alcoholics than in controls, the difference did not reach a level of significance. There was a similar decrease in 18:2 and an increase in 18:0 in cholesteryl esters of alcoholics as compared to controls. Results indicate that alcoholics in the United States show a similar change in certain serum lipids as reported for the Swedish alcoholics. This study also shows the complexities involved in selecting appropriate control groups to be compared with alcoholic patients. PMID:3395462

  6. Synthesis and Utility of Dihydropyridine Boronic Esters.

    PubMed

    Panda, Santanu; Coffin, Aaron; Nguyen, Q Nhu; Tantillo, Dean J; Ready, Joseph M

    2016-02-01

    When activated by an acylating agent, pyridine boronic esters react with organometallic reagents to form a dihydropyridine boronic ester. This intermediate allows access to a number of valuable substituted pyridine, dihydropyridine, and piperidine products. PMID:26694785

  7. Liquid Crystalline Thermosets from Ester, Ester-imide, and Ester-amide Oligomers

    NASA Technical Reports Server (NTRS)

    Dingemans, Theodorus J. (Inventor); Weiser, Erik S. (Inventor); St. Clair, Terry L. (Inventor)

    2009-01-01

    Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystaloligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oli-gomers are stable forup to an hour in the melt phase. They are highly processable by a variety of melt process shape forming and blending techniques. Once processed and shaped, the end-capped liquid crystal oigomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures.

  8. Purification of aqueous cellulose ethers

    SciTech Connect

    Bartscherer, K.A.; de Pablo, J.J.; Bonnin, M.C.; Prausnitz, J.M.

    1990-07-01

    Manufacture of cellulose ethers usually involves high amounts of salt by-products. For application of the product, salt must be removed. In this work, we have studied the injection of high-pressure CO{sub 2} into an aqueous polymer-salt solution; we find that upon addition of isopropanol in addition to CO{sub 2}, the solution separates into two phases. One phase is rich in polymer and water, and the other phase contains mostly isopropanol, water and CO{sub 2}. The salt distributes between the two phases, thereby offering interesting possibilities for development of a new purification process for water-soluble polymers. This work presents experimental phase-equilibrium data for hydroxyethyl cellulose and sodium carboxymethyl cellulose with sodium acetate and potassium sulfate, respectively, in the region 40{degree}C and 30 to 80 bar. Based on these data, we suggest a process for the manufacture and purification of water-soluble cellulose ethers. 15 refs., 14 figs., 9 tabs.

  9. REPRODUCTIVE TOXICITY OF PHTHALATE ESTERS

    EPA Science Inventory

    Phthalate esters display several modes of toxicity in mammalian species. In the rat, in utero exposure at relatively low dosage levels disrupts development of the reproductive system of the male rat by altering fetal testis hormone production. This presentation is a review of t...

  10. Trimerization of Phenyl Cyanate Ester

    NASA Astrophysics Data System (ADS)

    Pallaka, Madhusudhan Reddy; Simon, Sindee L.

    2015-03-01

    The kinetics of phenyl cyanate ester trimerization is studied in the bulk using differential scanning calorimetry. Dynamic experiments for different heating rates are analyzed for the activation energy using the model-free Kissinger-Akahira-Sunose(KAS) isoconversion method. The activation energy and other kinetic parameters are also obtained by fitting the dynamic data to a first order autocatalytic reaction model, which well describes the experimental data. The activation energy obtained from the KAS isoconversion method (70.1 kJ/mol) is in good agreement with that obtained from the kinetic model (73.2 kJ/mol) and is much lower than the more bulky cyanate esters studied in our laboratory, which have activation energies of approximately 95 kJ/mol. In addition, the rate constant for the phenyl cyanate ester is one to two orders higher than the bulkier cyanate esters in the temperature range of 200 to 300°C. Further elucidation of the dynamic experiments revealed a strong dependence of the reaction kinetics on the sample weight. Future work aims to understand this finding.

  11. Biodiesel With Optimized Fatty Ester Composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is largely composed of the mono-alkyl esters, usually methyl esters, of vegetable oils or animal fats with its fatty acid profile corresponding to that of the parent oil or fat. The different fatty esters have varying properties of relevance to biodiesel. The feedstock-dependent variatio...

  12. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under...

  13. 40 CFR 721.3034 - Methylamine esters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Methylamine esters. 721.3034 Section... Substances § 721.3034 Methylamine esters. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as methylamine esters (PMN P-94-982) is...

  14. 40 CFR 721.3034 - Methylamine esters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Methylamine esters. 721.3034 Section... Substances § 721.3034 Methylamine esters. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as methylamine esters (PMN P-94-982) is...

  15. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under...

  16. CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS

    SciTech Connect

    Kamil Klier; Richard G. Herman; Heock-Hoi Kwon; James G. C. Shen; Qisheng Ma; Robert A. Hunsicker; Andrew P. Butler; Scott J. Bollinger

    2003-03-01

    A tungstena-zirconia (WZ) catalyst has been investigated for coupling methanol and isobutanol to unsymmetrical ethers, i.e. methyl isobutyl ether (MIBE) and compared with earlier studied sulfated-zirconia (SZ) and Nafion-H catalysts. In all cases, the ether synthesis mechanism is a dual site S{sub N}2 process involving competitive adsorption of reactants on proximal acid sites. At low reaction temperatures, methylisobutylether (MIBE) is the predominant product. However, at temperatures >135 C the WZ catalyst is very good for dehydration of isobutanol to isobutene. The surface acid sites of the WZ catalyst and a Nafion-H catalyst were diagnosed by high resolution X-ray photoelectron spectroscopy (XPS) of N 1s shifts after adsorption of amines. Using pyridine, ethylenediamine, and triethylamine, it is shown that WZ has heterogeneous strong Broensted acid sites. Theoretical study located the transition state of the alcohol coupling reaction on proximal Broensted acid sites and accounted well for XPS core-level shifts upon surface acid-base interactions. While computations have not been carried out with WZ, it is shown that the SZ catalyst is a slightly stronger acid than CF{sub 3}SO{sub 3}H (a model for Nafion-H) by 1.3-1.4 kcal/mol. A novel sulfated zirconia catalyst having proximal strong Broensted acid sites was synthesized and shown to have significantly enhanced activity and high selectivity in producing MIBE or isobutene from methanol/isobutanol mixtures. The catalyst was prepared by anchoring 1,2-ethanediol bis(hydrogen sulfate) salt precursor onto zirconium hydroxide, followed by calcination to remove the -(CH{sub 2}CH{sub 2})- bridging residues.

  17. Ether-linked diglycerides inhibit vascular smooth muscle cell growth via decreased MAPK and PI3K/Akt signaling.

    PubMed

    Houck, Kristy L; Fox, Todd E; Sandirasegarane, Lakshman; Kester, Mark

    2008-10-01

    Diglycerides (DGs) are phospholipid-derived second messengers that regulate PKC-dependent signaling pathways. Distinct species of DGs are generated from inflammatory cytokines and growth factors. Growth factors increase diacyl- but not ether-linked DG species, whereas inflammatory cytokines predominately generate alkyl, acyl- and alkenyl, acyl-linked DG species in rat mesenchymal cells. These DG species have been shown to differentially regulate protein kinase C (PKC) isotypes. Ester-linked diacylglycerols activate PKC-epsilon and cellular proliferation in contrast to ether-linked DGs, which lead to growth arrest through the inactivation of PKC-epsilon. It is now hypothesized that ether-linked DGs inhibit mitogenesis through the inactivation of ERK and/or Akt signaling cascades. We demonstrate that cell-permeable ether-linked DGs reduce vascular smooth muscle cell growth by inhibiting platelet-derived growth factor-stimulated ERK in a PKC-epsilon-dependent manner. This inhibition is specific to the ERK pathway, since ether-linked DGs do not affect growth factor-induced activation of other family members of the MAPKs, including p38 MAPK and c-Jun NH(2)-terminal kinases. We also demonstrate that ether-linked DGs reduce prosurvival phosphatidylinositol 3-kinase (PI3K)/Akt signaling, independent of PKC-epsilon, by diminishing an interaction between the subunits of PI3K and not by affecting protein phosphatase 2A or lipid (phosphatase and tensin homologue deleted in chromosome 10) phosphatases. Taken together, our studies identify ether-linked DGs as potential adjuvant therapies to limit vascular smooth muscle migration and mitogenesis in atherosclerotic and restenotic models. PMID:18723771

  18. Enzymatic synthesis of lipophilic rutin and vanillyl esters from fish byproducts.

    PubMed

    Mbatia, Betty; Kaki, Shiva Shanker; Mattiasson, Bo; Mulaa, Francis; Adlercreutz, Patrick

    2011-07-13

    Lipase-catalyzed synthesis of lipophilic phenolic antioxidants was carried out with a concentrate of n-3 polyunsaturated fatty acids (PUFAs), recovered from oil extracted from salmon ( Salmon salar ) byproduct. Vanillyl alcohol and rutin were selected for the esterification reaction, and obtained esters yields were 60 and 30%, respectively. The antioxidant activities of the esters were compared with those of commercial butylated hydroxytoluene (BHT) and α-tocopherol using DPPH radical scavenging and thiobarbituric acid assays. In the DPPH assay, rutin esters showed better activity than vanillyl esters, and on the contrary in lipophilic medium, vanillyl esters were found to be superior to rutin esters. In bulk oil system, the antioxidant activities of rutin and vanillyl derivatives were lower than that of BHT and α-tocopherol, but in emulsion, they showed better activity than α-tocopherol. By attaching to natural phenolics, the PUFAs are protected against oxidation, and PUFA improves the hydrophobicity of the phenolic, which could enhance its function in lipid systems. PMID:21630661

  19. Metabolism of Diethyl Ether and Cometabolism of Methyl tert-Butyl Ether by a Filamentous Fungus, a Graphium sp

    PubMed Central

    Hardison, L. K.; Curry, S. S.; Ciuffetti, L. M.; Hyman, M. R.

    1997-01-01

    In this study, evidence for two novel metabolic processes catalyzed by a filamentous fungus, Graphium sp. strain ATCC 58400, is presented. First, our results indicate that this Graphium sp. can utilize the widely used solvent diethyl ether (DEE) as the sole source of carbon and energy for growth. The kinetics of biomass accumulation and DEE consumption closely followed each other, and the molar growth yield on DEE was indistinguishable from that with n-butane. n-Butane-grown mycelia also immediately oxidized DEE without the extracellular accumulation of organic oxidation products. This suggests a common pathway for the oxidation of both compounds. Acetylene, ethylene, and other unsaturated gaseous hydrocarbons completely inhibited the growth of this Graphium sp. on DEE and DEE oxidation by n-butane-grown mycelia. Second, our results indicate that gaseous n-alkane-grown Graphium mycelia can cometabolically degrade the gasoline oxygenate methyl tert-butyl ether (MTBE). The degradation of MTBE was also completely inhibited by acetylene, ethylene, and other unsaturated hydrocarbons and was strongly influenced by n-butane. Two products of MTBE degradation, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), were detected. The kinetics of product formation suggest that TBF production temporally precedes TBA accumulation and that TBF is hydrolyzed both biotically and abiotically to yield TBA. Extracellular accumulation of TBA accounted for only a maximum of 25% of the total MTBE consumed. Our results suggest that both DEE oxidation and MTBE oxidation are initiated by cytochrome P-450-catalyzed reactions which lead to scission of the ether bonds in these compounds. Our findings also suggest a potential role for gaseous n-alkane-oxidizing fungi in the remediation of MTBE contamination. PMID:16535667

  20. Borane-Catalyzed Reductive α-Silylation of Conjugated Esters and Amides Leaving Carbonyl Groups Intact.

    PubMed

    Kim, Youngchan; Chang, Sukbok

    2016-01-01

    Described herein is the development of the B(C6F5)3-catalyzed hydrosilylation of α,β-unsaturated esters and amides to afford synthetically valuable α-silyl carbonyl products. The α-silylation occurs chemoselectively, thus leaving the labile carbonyl groups intact. The reaction features a broad scope of both acyclic and cyclic substrates, and the synthetic utility of the obtained α-silyl carbonyl products is also demonstrated. Mechanistic studies revealed two operative steps: fast 1,4-hydrosilylation of conjugated carbonyls and then slow silyl group migration of a silyl ether intermediate. PMID:26549843

  1. Uptake and distribution of /sup 3/H-cholesteryl oleyl ether in tissues of cholesterol-fed New Zealand White and Watanabe Heritable Hyperlipidemic rabbits

    SciTech Connect

    McCormack, C.J.

    1988-01-01

    Cholesterol-fed New Zealand White (CH-FED) and Watanabe Heritable Hyperlipidemic (WHHL) rabbits with minimal, moderate, and severe atherosclerosis were injected with a non-degradable cholesteryl ester analogue, /sup 3/H-cholesteryl oleyl ether (/sup 3/H-COE), to identify organs and cells active in the uptake of plasma cholesteryl ester (CE) at critical stages in the progression of atherosclerosis. The iliac arteries were injured by balloon catheterization to compare the repair process between the two animals. The morphology of the antherosclerotic lesions and the physical state of the arterial lipid were also compared.

  2. Transesterification process to manufacture ethyl ester of rape oil

    SciTech Connect

    Korus, R.A.; Hoffman, D.S.; Bam, N.; Peterson, C.L.; Drown, D.C.

    1993-12-31

    A process for the production of the ethyl ester of winter rape [EEWR] for use as a biodiesel fuel has been studied. The essential part of the process is the transesterification of rape oil with ethanol, in the presence of a catalyst, to yield the ethyl ester of rape oil as a product and glycerin as a by-product. Experiments have been performed to determine the optimum conditions for the preparation of EEWR. The process variables were: (1) temperature, (2) catalyst, (3) rate of agitation, (4) water content of the alcohol used, and (5) the amount of excess alcohol used. The optimum conditions were: (1) room temperature, (2) 0.5% sodium methoxide or 1% potassium hydroxide catalyst by weight of rapeseed oil, (3) extremely vigorous agitation with some splashing during the initial phase of the reaction and agitation was not necessary after the reaction mixture became homogeneous, (4) absolute ethanol was necessary for high conversion, and (5) 50% excess ethanol with NaOCH{sub 3} or 100% excess with KOH gave a maximum conversion. Viscosity, cloud point and pour point of the EEWR were measured. A preliminary break-even cost for the commercial production of EEWR was found to be $0.55/liter [$2.08/US gallon].

  3. Toxicity of phosphor esters: Willy Lange (1900-1976) and Gerda von Krueger (1907-after 1970).

    PubMed

    Petroianu, G A

    2010-10-01

    In 1851 Williamson serendipitously discovered a new and efficient way to produce ethers using ethyl iodide and potassium salts. Based on this new synthetic approach, the Frenchman Philippe de Clermont and the Muscovite Wladimir Moschnin, both élèves of Adolphe Wurtz in his Paris School of Chemistry, achieved the synthesis of the first ester of pyrophosphoric acid (TEPP). de Clermont "tasted" the new compound and although TEPP is a potent cholinesterase inhibitor he failed to recognize its toxicity. Almost a century later, in 1932, Willy Lange (1900-1976) and his graduate student Gerda v. Krueger (1907-after 1970) described the toxicity of organophosphonates. While the classic paper of the two "Uber Ester der Monofluorphosphorsäure." is cited by almost everybody working in the field, little is known about Lange and almost nothing about v. Krueger. This brief communication attempts to shed some light on the life of both. PMID:21105582

  4. Inhibition of MMPs by alcohols

    PubMed Central

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

    2011-01-01

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

  5. Alkali-Ion-Crown Ether in Art and Conservation: The Applied Bioinorganic Chemistry Approach

    PubMed Central

    Hilfrich, Uwe; Taylor, Harold; Weser, Ulrich

    2004-01-01

    Dried varnish is rich in many ester moieties, which may be broken down into small, soluble compounds by esterase activity or alkaline hydrolysis. Two methods for varnish removal have been developed, including the treatment of either lipase or RbOH / PEG-400 crown ether which allow aged oil varnishes or paint coverings to be removed or thinned. These techniques are designed to proceed in a controlled manner without damaging lower paint or base layers. Unfortunately, lipase did not react with the aged ester groups of dried linseed oil varnish. Surprisingly, the varnish came off in the presence of Tris buffer alone which, in addition, formed reactive metal complexes. A better choice was the use of high Mr alkali ion polyethylene glycol–400 (PEG-400) crown ether type chelates. PEG-400 complexes alkali ions including rubidium and other alkaliions impeding the diffusion of their basic counter ions into lower varnish or paint layers. Possible migration of alkali metal ions into the paint layer during alkaline varnish removal was determined by labelling the cleansing solutions with 86Rb. Fortunately, varnish is degraded on the surface only. Lower paint or varnish layers are not attacked even if chemically similar to the varnish or over painting to be removed as virtually no 86Rb was detected on the paint surface. PMID:18365066

  6. Development of nanocomposites reinforced with carboxylated poly(ether ether ketone) grafted to zinc oxide with superior antibacterial properties.

    PubMed

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2014-03-12

    Novel poly(ether ether ketone) (PEEK) based nanocomposites have been fabricated via melt-blending by addition of a carboxylated polymer derivative covalently grafted onto the surface of hydroxyl-terminated ZnO nanoparticles. Their morphology, thermal, mechanical, tribological, and antibacterial properties have been analyzed and compared with those of composites reinforced with pristine ZnO. The Fourier transform infrared (FT-IR) spectra corroborate the success of the grafting reaction, showing the appearance of signals related to ester linkages. Microscopic observations demonstrate that the polymer grafting improves the nanoparticle dispersion within the matrix. A progressive rise in thermal stability and flame retardant ability is found with increasing ZnO concentration, with an exceptional increment in the maximum degradation rate temperature of 70 °C at 5.0 wt % loading. The crystallization and melting temperature of PEEK decrease upon incorporation of the grafted nanofillers, attributed to the restrictions on polymer chain mobility and crystal growth imposed by the strong ZnO-matrix interactions. Nanocomposites with polymer-grafted nanoparticles exhibit higher stiffness, strength, ductility, toughness and glass transition temperature whilst lower coefficient of friction and wear rate than the neat polymer and composites with bare ZnO. Further, they show superior antibacterial activity against both the Gram-negative Escherichia coli and the Gram-positive Staphylococcus aureus bacteria. The antimicrobial effect increases upon raising nanoparticle content, and is stronger on E. coli. The approach used in this work is a simple, scalable, and efficient method to improve the performance of PEEK/ZnO nanocomposites for use in biomedical applications such as trauma, orthopedics, and spinal implants. PMID:24552261

  7. Alcohol Energy Drinks

    MedlinePlus

    ... Home / About Addiction / Alcohol / Alcohol Energy Drinks Alcohol Energy Drinks Read 14635 times font size decrease font size increase font size Print Email Alcohol energy drinks (AEDs) or Caffeinated alcoholic beverages (CABs) are ...

  8. Alcohol Energy Drinks

    MedlinePlus

    ... Home / About Addiction / Alcohol / Alcohol Energy Drinks Alcohol Energy Drinks Read 17728 times font size decrease font size increase font size Print Email Alcohol energy drinks (AEDs) or Caffeinated alcoholic beverages (CABs) are ...

  9. Alcohol during Pregnancy

    MedlinePlus

    ... Home > Pregnancy > Is it safe? > Alcohol during pregnancy Alcohol during pregnancy E-mail to a friend Please ... and fetal alcohol spectrum disorders. How does drinking alcohol during pregnancy affect your baby's health? Drinking alcohol ...

  10. Solvent-induced crystallization of poly(ether ether ketone)

    NASA Astrophysics Data System (ADS)

    McPeak, Jennifer Lynne

    The purpose of this study was learn how the diffusion, swelling, and crystallization processes are coupled during solvent-induced crystallization of poly(ether ether ketone) (PEEK). Unoriented amorphous PEEK films were immersed in aprotic organic liquids at ambient temperature and bulk properties or characteristics were monitored as a function of immersion time. The sorption behavior, T g and Tm° suppression, crystallinity, and dynamic mechanical response were correlated as a function of solvent chemistry and immersion time. The saturation time of methylene chloride, 1,3-dichloropropane, tetrahydrofuran, cyclopentanone, chlorobenzene, toluene, diethyl ketone, and ethylbenzene in amorphous PEEK films were found to range from hours to days depending on the level of polymer-solvent interactions. In-situ isochronal DMA spectra show that the Tg of PEEK was suppressed from 150°C to below ambient temperature such that crystallization was kinetically feasible during ambient immersion. In addition, an increase in viscoelastic dispersion was attributed to the presence of crystallinity. From dynamic mass uptake and wide-angle x-ray diffraction (WAXD) results, it was found that the bulk sorption rate was equal to the bulk crystallization rate for all solvent systems that promoted SINC and PEEK exhibited diffusion-limited crystallization, irrespective of the nature of the transport mechanism. In addition, the solvent-induced crystals exhibit preferred orientation as supported by photographic WAXD. A distinct sorption front, observed with scanning electron microscopy, further supports the scenario of diffusion-controlled crystallization and one-dimensional diffusion. Isothermal DMA spectra for THF, cyclopentanone, and chlorobenzene, indicate that, as the solvent diffuses into the films, the stiffness of the polymer decreases at short times, begins to increase, and then reaches a relatively time-independent value. It was determined that the initial decrease in the storage

  11. Enantiospecific Alkynylation of Alkylboronic Esters

    PubMed Central

    Wang, Yahui; Noble, Adam; Myers, Eddie L.

    2016-01-01

    Abstract Enantioenriched secondary and tertiary alkyl pinacolboronic esters undergo enantiospecific deborylative alkynylation through a Zweifel‐type alkenylation followed by a 1,2‐elimination reaction. The process involves use of α‐lithio vinyl bromide or vinyl carbamate species, for which application to Zweifel‐type reactions has not previously been explored. The resulting functionalized 1,1‐disubstituted alkenes undergo facile base‐mediated elimination to generate terminal alkyne products in high yield and excellent levels of enantiospecificity over a wide range of pinacolboronic ester substrates. Furthermore, along with terminal alkynes, internal and silyl‐protected alkynes can be formed by simply introducing a suitable carbon‐ or silicon‐based electrophile after the base‐mediated 1,2‐elimination reaction. PMID:26934427

  12. ESTER: Evolution STEllaire en Rotation

    NASA Astrophysics Data System (ADS)

    Rieutord, Michel

    2013-05-01

    The ESTER code computes the steady state of an isolated star of mass larger than two solar masses. The only convective region computed as such is the core where isentropy is assumed. ESTER provides solutions of the partial differential equations, for the pressure, density, temperature, angular velocity and meridional velocity for the whole volume. The angular velocity (differential rotation) and meridional circulation are computed consistently with the structure and are driven by the baroclinic torque. The code uses spectral methods, both radially and horizontally, with spherical harmonics and Chebyshev polynomials. The iterations follow Newton's algorithm. The code is object-oriented and is written in C++; a python suite allows an easy visualization of the results. While running, PGPLOT graphs are displayed to show evolution of the iterations.

  13. Segmented polyether-ester copolymers

    SciTech Connect

    Souffie, R.D.

    1982-08-01

    This article touches on the chemistry of manufacture and structure of thermoplastic elastomers. The physical properties and environmental resistance characteristics of these copolymers are related to their molecular makeup. Results indicate that segmented polyether esters, because of their basic chemical structure, are resistant to a wide range of oils, solvents and chemicals. They are also highly elastic, resilient polymers which can be both cost and performance effective when used in a number of industrial applications.

  14. Influence of Grape Composition on Red Wine Ester Profile: Comparison between Cabernet Sauvignon and Shiraz Cultivars from Australian Warm Climate.

    PubMed

    Antalick, Guillaume; Šuklje, Katja; Blackman, John W; Meeks, Campbell; Deloire, Alain; Schmidtke, Leigh M

    2015-05-13

    The relationship between grape composition and subsequent red wine ester profile was examined. Cabernet Sauvignon and Shiraz, from the same Australian very warm climate vineyard, were harvested at two different stages of maturity and triplicate wines were vinified. Grape analyses focused on nitrogen and lipid composition by measuring 18 amino acids by HPLC-FLD, 3 polyunsaturated fatty acids, and 6 C6-compounds derived from lipid degradation by GC-MS. Twenty esters and four higher alcohols were analyzed in wines by HS-SPME-GC-MS. Concentrations of the ethyl esters of branched acids were significantly affected by grape maturity, but the variations were inconsistent between cultivars. Small relative variations were observed between wines for ethyl esters of fatty acids, whereas higher alcohol acetates displayed the most obvious differences with concentrations ranging from 1.5- to 26-fold higher in Shiraz than in Cabernet Sauvignon wines regardless of the grape maturity. Grape analyses revealed the variations of wine ester composition might be related to specific grape juice nitrogen composition and lipid metabolism. To the authors' knowledge the present study is the first to investigate varietal differences in the ester profiles of Shiraz and Cabernet Sauvignon wines made with grapes harvested at different maturity stages. PMID:25905977

  15. Alcohol conversion

    DOEpatents

    Wachs, Israel E.; Cai, Yeping

    2002-01-01

    Preparing an aldehyde from an alcohol by contacting the alcohol in the presence of oxygen with a catalyst prepared by contacting an intimate mixture containing metal oxide support particles and particles of a catalytically active metal oxide from Groups VA, VIA, or VIIA, with a gaseous stream containing an alcohol to cause metal oxide from the discrete catalytically active metal oxide particles to migrate to the metal oxide support particles and to form a monolayer of catalytically active metal oxide on said metal oxide support particles.

  16. Variables affecting the yields of fatty esters from transesterified vegetable oils

    SciTech Connect

    Freedman, B.; Pryde, E.H.; Mounts, T.L.

    1984-10-01

    Transesterification reaction variables that affect yield and purity of the product esters from cottonseed, peanut, soybean and sunflower oils include molar ratio of alcohol to vegetable oil, type of catalyst (alkaline vs acidic), temperature and degree of refinement of the vegetable oil. With alkaline catalysts (either sodium hydroxide or methoxide), temperatures of 60 degrees C or higher, molar ratios of at least 6 to 1 and with fully refined oils, conversion to methyl, ethyl and butyl esters was essentially complete in 1 hr. At moderate temperatures (32 degrees C), vegetable oils were 99% transesterified in ca. 4 hr with an alkaline catalyst. Transesterification by acid catalysis was much slower than by alkali catalysis. Although the crude oils could be transesterified, ester yields were reduced because of gums and extraneous material present in the crude oils. 30 references.

  17. The thickening additives for mineral and synthetic oils based on the copolymers of alkyl acrylates or methacrylates and butyl vinyl ether

    NASA Astrophysics Data System (ADS)

    Geraskina, Evgeniya V.; Moikin, Alexey A.; Semenycheva, Ludmila L.

    2014-05-01

    A new method for synthesizing of the copolymers of acrylic and methacrylic acid esters with butyl vinyl ether in an excess of low-boiling monomer, which has proven effective for a number of alkyl methacrylates was proposed. Tests of thickening efficiency of the obtained copolymers were carried out. The resistance to mechanical degradation of the mineral, semi synthetic and synthetic base oils doped with the copolymers was evaluated.

  18. Phenylethynl-terminated poly(arylene ethers)

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor); Bryant, Robert G. (Inventor); Hergenrother, Paul M. (Inventor)

    1993-01-01

    Phenylethynyl-terminated poly(arylene ethers) are prepared in a wide range of molecular weights by adjusting monomer ratio and adding an appropriate amount of 4-fluoro- 4'-phenylethynyl benzophenone during polymer synthesis. The resulting phenylethynyl-terminated poly(arylene ethers) react and crosslink upon curing for one hour at 350 C to provide materials with improved solvent resistance, higher modulus, and better high temperature properties than the linear, uncrosslinked polymers.

  19. Imide/arylene ether copolymers. I

    NASA Technical Reports Server (NTRS)

    Jensen, B. J.; Hergenrother, P. M.; Bass, R. G.

    1991-01-01

    The preparation of a series of novel imide/arylene ether copolymers is described together with the results of viscosity and DSC Tg(Tm) measurements. The copolymers were synthesized from an arylene ether block and either an amorphous or semicrystalline imide block. One block copolymer was end-capped, and the molecular weight was controlled to improve compression moldability. The paper also presents results of mechanical properties tests on copolymer samples.

  20. Alcohol withdrawal

    MedlinePlus

    ... Seeing or feeling things that aren't there (hallucinations) Seizures Severe confusion ... alcohol withdrawal. You will be watched closely for hallucinations and other signs of delirium tremens. Treatment may ...

  1. Alcoholism (image)

    MedlinePlus

    ... that interferes with physical or mental health, and social, family or job responsibilities. This addiction can lead to liver, circulatory and neurological problems. Pregnant women who drink alcohol in any amount ...

  2. Conversion of unsaturated alcohols into functionalized tetrahydrofurans and tetrahydropyrans via nitrile oxide dipolar cycloadditions

    SciTech Connect

    Hassner, A.; Murthy, K.S.K. ); Padwa, A.; Dean, D.C.; Schoffstall, A.M. ); Chiacchio, U. )

    1989-10-27

    The intramolecular nitrile oxide cycloaddition (INOC) of a series of unsaturated oximino ethers has been investigated. The synthesis of the olefinic nitrile oxides involves treating an unsaturated alcohol with a {alpha}-bromoalkanal O-(trimethylsilyl)oxime in the presence of fluoride ion followed by subsequent sodium hypochlorite oxidation. The nitrile oxides were not isolated but spontaneously underwent intramolecular cycloaddition to give fused five- and six-membered ring ethers. The preferred stereoisomer in the formation of the five-membered ring ethers is trans, whereas in the six-membered ring ethers the cis isomer predominates. MM2 calculations help rationalize the observed stereoselectivity. The ratio of diastereomeric products from the INOC reaction appears to correlate with product stabilities. Simple heating of some of the oximino ethers led to intramolecular cycloaddition. The ring closure apparently proceeds subsequent to a tautomeric equilibration of the oxime with a transient nitrone which is trapped by the neighboring {pi}-bond.

  3. Physicochemical characterization of dilute n-alcohol/biodiesel mixtures by inverse gas chromatography.

    PubMed

    Bobbitt, N Scott; King, Jerry W

    2010-12-10

    Inverse gas chromatography (IGC) has been used to determine the physicochemical parameters that characterize solution thermodynamic interactions in biodiesel-n-alcohol solute systems. Such data is of value to chemical engineers and separation scientists in optimizing separation processes to separate alcoholic solutes at low concentrations in soybean oil methyl ester mixtures (biodiesel). The derived activity and Henry's Law coefficient data can be used to rationalize the interaction of four members of an n-alcoholic homologous series and the soya-based methyl ester solvent in terms of such esters as "green" renewable solvents. Sorption isotherm data confirm linear behavior in most cases between the solute (alcohol) vapor state concentrations and their uptake into the biodiesel phase. Overall, the experimentally determined activity coefficients agree well with those predicted by solution thermodynamic theories as well as correlative chemical engineering equations. PMID:21067759

  4. Liquid Crystalline Thermosets from Ester, Ester-Imide, and Ester-Amide Oligomers

    NASA Technical Reports Server (NTRS)

    Dingemans, Theodornus J. (Inventor); Weiser, Erik S. (Inventor); SaintClair, Terry L. (Inventor)

    2005-01-01

    Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,OOO grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end- capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.

  5. Liquid crystalline thermosets from ester, ester-imide, and ester-amide oligomers

    NASA Technical Reports Server (NTRS)

    Dingemans, Theodorous J. (Inventor); Weiser, Erik S. (Inventor); St. Clair, Terry L. (Inventor)

    2005-01-01

    Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.

  6. Phthalates and polybrominated diphenyl ethers in retail stores

    NASA Astrophysics Data System (ADS)

    Xu, Ying; Liang, Yirui; Urquidi, Jorge R.; Siegel, Jeffrey A.

    2014-04-01

    Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories, because they are extensively used as additives in consumer products and associated with serious health concerns. This study measured six phthalate and 14 PBDE compounds inside of 12 retail stores in Texas and Pennsylvania, U.S. Phthalates and PBDEs were widely found in the retail environment, indicating that they are ubiquitous indoor air pollutants. DEP, DnBP, and DEHP were the most abundant phthalates, with DnBP showing the highest concentration (0.23 ± 0.36 μg m-3). PBDEs were dominated by BDE-28, -99, and -209, having concentrations as high as 0.85 ± 1.99 ng m-3 (BDE-99). The levels of phthalates and PBDEs measured in this study are comparable to concentrations found in previous investigations of residential buildings, with phthalates showing lower concentrations and PBDEs exhibiting higher concentrations in retail stores. The potential co-occurrence of phthalates was not as strong as that of PBDEs, suggesting that phthalates might have more diverse sources. Whole building emission rates were calculated and showed similar patterns of variations as indoor air concentrations, suggestion the diversity of indoor sources of phthalates and PBDEs in retail environments.

  7. Process for the generation of .alpha., .beta.-unsaturated carboxylic acids and esters using niobium catalyst

    DOEpatents

    Gogate, Makarand Ratnakav; Spivey, James Jerome; Zoeller, Joseph Robert

    1999-01-01

    A process using a niobium catalyst includes the step of reacting an ester or carboxylic acid with oxygen and an alcohol in the presence a niobium catalyst to respectively produce an .alpha.,.beta.-unsaturated ester or carboxylic acid. Methanol may be used as the alcohol, and the ester or carboxylic acid may be passed over the niobium catalyst in a vapor stream containing oxygen and methanol. Alternatively, the process using a niobium catalyst may involve the step of reacting an ester and oxygen in the presence the niobium catalyst to produce an .alpha.,.beta.-unsaturated carboxylic acid. In this case the ester may be a methyl ester. In either case, niobium oxide may be used as the niobium catalyst with the niobium oxide being present on a support. The support may be an oxide selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide and mixtures thereof. The catalyst may be formed by reacting niobium fluoride with the oxide serving as the support. The niobium catalyst may contain elemental niobium within the range of 1 wt % to 70 wt %, and more preferably within the range of 10 wt % to 30 wt %. The process may be operated at a temperature from 150 to 450.degree. C. and preferably from 250 to 350.degree. C. The process may be operated at a pressure from 0.1 to 15 atm. absolute and preferably from 0.5-5 atm. absolute. The flow rate of reactants may be from 10 to 10,000 L/kg.sub.(cat) /h, and preferably from 100 to 1,000 L/kg.sub.(cat) /h.

  8. Anaerobic biodegradation of ether compounds by ether bond-cleaving bacteria and methanogenic consortia

    SciTech Connect

    Dwyer, D.F.

    1989-01-01

    Ether compounds are manufactured for use in nonionic detergents, plastics, pesticides and other products and occur as toxic organic compounds, the most famous being tetrachlorodibenzo-p-dioxin. Ether compounds were considered recalcitrant to anaerobic biodegradation due to the lack of an appropriate oxidant for ether bond-cleavage in reducing environments. Many of these compounds reside in anaerobic environments or are exposed to anaerobic waste treatment processes. Thus, it is of interest to identify: (i) whether ether compounds are anaerobically biodegradable, (ii) the anaerobic microorganisms able to degrade these compounds, and (iii) the mechanism(s) of anaerobic ether bond-cleavage. The ether bonds of polyethylene glycol (PEG; HO-(CH{sub 2}CH{sub 2}-O-){sub n}H), phenyl ether ((C{sub 6}H{sub 5}){sub 2}O), and dibenzo-p-dioxin ((C{sub 6}H{sub 4}){sub 2}O{sub 2}) were shown to be degraded in methanogenic consortia enriched with these compounds and polyethoxylate (nonionic) surfactants as substrates. Two anaerobic microorganisms which used PEGs as sole substrates were isolated and characterized. Desulfovibrio desulfuricans strain DG2 degraded the monomer ethylene glycol and oligomers up to tetraethylene glycol (HO-(CH{sub 2}CH{sub 2}-O-){sub 4}H) in length. Bacteroides sp. strain PG1 degraded diethylene glycol and all other polymer lengths of PEG. PEGs were degraded by Bacteroides sp. strain PG1 via an external depolymerization which was either a hydrolytic or a reductive cleavage of the ether bond. The ether bond of diaryl ethers was apparently cleaved by a reductive mechanism which produced benzene and phenol as products from phenyl ether degradation and benzene and, by indirect analysis, catechol from dibenzo-dioxin.

  9. Structure of pyridine and quinoline vinyl ethers according to data from /sup 1/H and /sup 13/C NMR spectra and quantum-chemical calculations

    SciTech Connect

    Afonin, A.V.; Voronov, V.K.; Andriankov, M.A.; Danovich, D.K.

    1987-08-10

    A systematic investigation of the structure of the vinyl ethers of heterocyclic compounds has not been undertaken. The present work was devoted to investigation of the stereochemical and electronic structure of the vinyl ethers of pyridine and quinoline. The PMR spectra of the samples were recorded for 5% solutions in deuterochloroform on a Tesla BS-497 spectrometer at 100 MHz. The /sup 13/C NMR spectra were recorded on a Tesla BS-567A spectrometer at 25.1 MHz in deuterochloroform with the samples at concentrations of 30%. The internal standard was HMDS. The vinyl ethers of pyridine and quinoline exist preferentially in the nonplanar S-trans conformation. In the vinyl esters of pyridine and quinoline the p-..pi.. conjugation is concurrent in nature and depends on the position of the vinyloxy group in the heterocycle.

  10. Alcohol Abuse: Alcohol Withdrawal Syndrome

    MedlinePlus

    ... they quit drinking. What are the symptoms of alcohol withdrawal syndrome? Symptoms can be mild or severe, and may include: Shakiness Sweats Anxiety Irritability Fatigue Depression Headaches Insomnia Nightmares Decreased appetite More severe withdrawal symptoms ...

  11. Novel acyloxy derivatives of branched mono- and polyol esters of sal fat: multiviscosity grade lubricant base stocks.

    PubMed

    Kamalakar, Kotte; Sai Manoj, Gorantla N V T; Prasad, Rachapudi B N; Karuna, Mallampalli S L

    2014-12-10

    Sal fat, a nontraditional seed oil, was chemically modified to obtain base stocks with a wide range of specifications that can replace mineral oil base stocks. Sal fatty acids were enriched to 72.6% unsaturation using urea adduct method and reacted with branched mono alcohol, 2-ethylhexanol (2-EtH), and polyols namely neopentyl glycol (NPG) and trimethylolpropane (TMP) to obtain corresponding esters. The esters were hydroxylated and then acylated using propionic, butyric, and hexanoic anhydrides to obtain corresponding acylated derivatives. The acylated TMP esters exhibited very high viscosities (427.35-471.93 cSt at 40 °C) similar to those of BS 150 mineral oil base stock range, ISO VG 460, while the acylated NPG esters (268.81-318.84 cSt at 40 °C) and 2-EtH esters viscosities (20.94-24.44 cSt at 40 °C) exhibited viscosities in the range of ISO VG 320 and 22 respectively with good viscosity indices. Acylated NPG esters were found suitable for high temperature and acylated 2-ethylhexyl esters for low viscosity grade industrial applications. It was observed that the thermo-oxidative stabilities of all acylated products were found better compared to other vegetable oil based base stocks. Overall, all the sal fat based lubricant base stocks are promising candidates with a wide range of properties, which can replace most of the mineral oil base stocks with appropriate formulations. PMID:25416127

  12. Umpolung Reactions of α-Imino Esters: Useful Methods for the Preparation of α-Amino Acid Frameworks.

    PubMed

    Mizota, Isao; Shimizu, Makoto

    2016-04-01

    This paper summarizes our recent efforts toward the development of tandem reactions utilizing umpolung reactions of α-imino esters. A highly diastereoselective tandem N-alkylation-Mannich reaction of α-imino esters was developed. A tandem N-alkylation-addition reaction of α-imino esters derived from ethyl glyoxylate with various aldehydes proceeded to give 1,2-amino alcohols. The same reaction also proceeded efficiently using a novel flow system comprising two connected microreactors. Novel syntheses of α-quaternary alkynyl amino esters and allenoates were developed through the use of umpolung N-addition to β,γ-alkynyl α-imino esters, followed by regioselective acylation. In addition, a highly regioselective tandem N-alkylation-vinylogous aldol reaction of β,γ-alkenyl α-imino esters was discovered. N-Alkylation of α-iminophosphonates followed by a Horner-Wadsworth-Emmons reaction with aldehydes occurred to afford enamines, which can be used in a four-component coupling reaction with methyl vinyl ketone. α-N-Acyloxyimino esters served as highly efficient substrates for the N,N,C-trialkylation reaction to introduce various nucleophiles at the imino nitrogen and carbon atoms. PMID:26833635

  13. 21 CFR 172.859 - Sucrose fatty acid esters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sucrose fatty acid esters. 172.859 Section 172.859... CONSUMPTION Multipurpose Additives § 172.859 Sucrose fatty acid esters. Sucrose fatty acid esters identified...) Sucrose fatty acid esters are the mono-, di-, and tri-esters of sucrose with fatty acids and are...

  14. Chemoselective Boronic Ester Synthesis by Controlled Speciation**

    PubMed Central

    Fyfe, James W B; Seath, Ciaran P; Watson, Allan J B

    2014-01-01

    Control of boronic acid solution speciation is presented as a new strategy for the chemoselective synthesis of boronic esters. Manipulation of the solution equilibria within a cross-coupling milieu enables the formal homologation of aryl and alkenyl boronic acid pinacol esters. The generation of a new, reactive boronic ester in the presence of an active palladium catalyst also facilitates streamlined iterative catalytic C=C bond formation and provides a method for the controlled oligomerization of sp2-hybridized boronic esters. PMID:25267096

  15. Effects of gamma-ray irradiation on a cyanate ester/epoxy resin

    NASA Astrophysics Data System (ADS)

    Idesaki, Akira; Uechi, Hiroki; Hakura, Yoshihiko; Kishi, Hajime

    2014-05-01

    Effects of γ-ray irradiation on a cyanate ester/epoxy resin composed of dicyanate ester of bisphenol A (DCBA) and diglycidyl ether of bisphenol A (DGEBA) were investigated by changes in physicochemical and mechanical properties after the γ-ray irradiation with dose of 100 MGy as maximum at around 40 °C under vacuum. After the irradiation, gases of hydrogen, carbon monoxide and carbon dioxide were evolved, glass transition temperature decreased, and flexural strength also decreased. It was concluded that ether linkages bonded to cyanurate, isocyanurate and oxazolidinone structures are mainly decomposed by the irradiation. After 100 MGy irradiation, the flexural strength of DCBA/DGEBA was maintained more than 170 MPa which is 90% of initial value of 195 MPa. Flexural modulus and density slightly increased to the values of 3.9 GPa and 1.211 g/cm3 from initial values of 3.4 GPa and 1.199 g/cm3, respectively.

  16. Conformations and Barriers to Methyl Group Internal Rotation in Two Asymmetric Ethers: Propyl Methyl Ether and Butyl Methyl Ether

    NASA Astrophysics Data System (ADS)

    Long, B. E.; Dechirico, F.; Cooke, S. A.

    2012-06-01

    The conformational preferences of the O-C-C-C unit are important in many biological systems with the unit generally preferring a gauche configuration compared to an anti configuration. Butyl methyl ether and propyl methyl ether provide very simple systems for this phenomenom to manifest. Pure rotational spectra of the title molecules have been recorded using chirped pulse Fourier transform microwave spectroscopy (CP-FTMW). In the case of butyl methyl ether, only one conformer has been observed. This conformer has torsional angles of COCC = 180°, OCCC = 62° and CCCC = 180° (anti-gauche-anti) and rotational constants of A = 10259.4591(33) MHz, B = 1445.6470(13) MHz, and C = 1356.2944(14) MHz. The rotational spectrum was doubled and has been analyzed to produce an effective barrier to methyl group internal rotation of 780(35) cm-1. A prior rotational spectroscopic study on propyl methyl ether had focused only on the high energy anti-anti conformer. We have analyzed spectra from the lowest energy anti-gauche conformer and the spectroscopic constants will be presented. A summary of the differences in conformational energies and methyl group internal rotation barriers for the class of aliphatic asymmetric ethers will be presented. K. N. Houk, J. E. Eksterowicz, Y.-D. Wu, C. D. Fuglesang, D. B. Mitchell. J. Am. Chem. Soc. 115 (4170), 1993. Hiroshi Kato, Jun Nakagawa, Michiro Hayashi. J. Mol. Spectrosc. 80 (272), 1980.

  17. Synthesis and properties of fluorous benzoquinones and their application in deprotection of silyl ethers.

    PubMed

    Matsubara, Hiroshi; Maegawa, Takahiko; Kita, Yasuaki; Yokoji, Takato; Nomoto, Akihiro

    2014-08-01

    1,4-Benzoquinone derivatives bearing trifluoromethyl, perfluorobutyl and perfluorohexyl groups were prepared and employed in the deprotection of silyl ethers. The fluorous character of these compounds was examined by measuring the partition coefficient between the fluorous and organic solvents. The benzoquinone derivatives showed significant fluorous character, indicating that they can be recovered from the reaction mixtures using a fluorous/organic biphasic system. The oxidising ability of the fluorous benzoquinones was estimated by cyclic voltammetry, and these compounds were found to be strong oxidisers. The fluorous benzoquinones were utilised in the oxidative desilylation of silyl ethers to afford the deprotected alcohols in high yield. In addition, the reduced fluorous benzoquinones were recovered from the reaction mixtures in good yields using a fluorous/organic biphasic system. PMID:24937383

  18. Mesoporous nickel-aluminosilicate nanocomposite: a solid acid catalyst for ether synthesis.

    PubMed

    Neelakandeswari, N; Karvembu, R; Dharmaraj, N

    2013-04-01

    Mesoporous nickel aluminosilicate, a solid acid catalyst prepared by sol-gel technique was utilized as a heterogeneous catalyst for the synthesis of symmetrical ethers by dehydro-condensation of alcohols. The prepared catalysts were characterized by Fourier-transform infra red spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), N2 adsorption-desorption analysis, temperature programmed desorption of ammonia (TPD) and X-ray photoelectron spectroscopic techniques. The presence of the catalyst assisted the etherification reaction in 30 minutes. Ethers formed in these reactions were quantified by gas chromatography (GC) and the identities of few of them were confirmed by nuclear magnetic resonance spectral data (NMR). PMID:23763171

  19. Biotransformation of methyl tert-butyl ether by human cytochrome P450 2A6.

    PubMed

    Shamsipur, Mojtaba; Miran Beigi, Ali Akbar; Teymouri, Mohammad; Poursaberi, Tahereh; Mostafavi, S Mojtaba; Soleimani, Parviz; Chitsazian, Fereshteh; Tash, Shahram Abolhassan

    2012-04-01

    Methyl tert-butyl ether (MTBE) is widely used as gasoline oxygenate and octane number enhancer for more complete combustion in order to reduce the air pollution caused by motor vehicle exhaust. The possible adverse effects of MTBE on human health are of major public concern. However, information on the metabolism of MTBE in human tissues is scarce. The present study demonstrates that human cytochrome P450 2A6 is able to metabolize MTBE to tert-butyl alcohol (TBA), a major circulating metabolite and marker for exposure to MTBE. As CYP2A6 is known to be constitutively expressed in human livers, we infer that it may play a significant role in metabolism of gasoline ethers in liver tissue. PMID:21915685

  20. Four 3-cyanodifurazanyl ethers: potential propellants.

    PubMed

    Averkiev, Boris B; Antipin, Mikhail Yu; Sheremetev, Aleksey B; Timofeeva, Tatiana V

    2003-07-01

    In earlier papers, we described the synthesis and structures of bis(3-nitrofurazan-4-yl) ether, C(4)N(6)O(7), (I), bis[3-(nitro-N,N,O-azoxy)furazan-4-yl] ether, C(4)N(10)O(9), (II), and bis[3-(5H-[1,2,3]triazolo[4,5-c]furazan-5-yl)furazan-4-yl] ether, C(8)N(14)O(5), (III). Here we compare the structures of (I)-(III) with those of four 3-cyanodifurazanyl ethers, namely bis(3-cyanofurazan-4-yl) ether, C(6)N(6)O(3), (IV), 3-cyanofurazanyl 3-nitrofurazanyl ether, C(5)N(6)O(5), (V), 3,4-bis(3-cyanofurazan-4-yloxy)furazan, C(8)N(8)O(5), (VI), and bis[3-(3-cyanofurazan-4-yloxy)furazan-4-yl]diazene, C(10)N(12)O(6), (VII). It was found that the geometric parameters of the difurazanyl ether fragments are similar in these structures and therefore not influenced by substituent effects; however, the conformation of this fragment is different, viz. structures (I), (III), (V) and (VI) have approximate C(2) symmetry, and structures (II), (IV) and (VII) have C(s) symmetry. Dense crystal packing (1.626-1.898 Mg m(-3)) is characteristic for all these hydrogen-free compounds. A linear correlation is also determined between crystal density and 'molecular density' (M/V), where M is the mass of a molecule and V is the molecular volume. PMID:12855864

  1. Fumaric acid esters in dermatology

    PubMed Central

    Wollina, Uwe

    2011-01-01

    Fumaric acid esters (FAE) are substances of interest in dermatology. FAE exert various activities on cutaneous cells and cytokine networks. So far only a mixture of dimethylfumarate (DMF) and three salts of monoethylfumarate (MEF) have gained approval for the oral treatment of moderate-to-severe plaque-type psoriasis in Germany. DMF seems to be the major active component. There is evidence that FAE are not only effective and safe in psoriasis but granulomatous non-infectious diseases like granuloma annulare, necrobiosis lipoidica and sarcoidosis. In vitro and animal studies suggest some activity in malignant melanoma as well. PMID:23130241

  2. Steroidal esters from Ferula sinkiangensis.

    PubMed

    Li, Guangzhi; Li, Xiaojin; Cao, Li; Shen, Liangang; Zhu, Jun; Zhang, Jing; Wang, Junchi; Zhang, Lijing; Si, Jianyong

    2014-09-01

    Two new steroidal esters with an unusual framework, Sinkiangenorin A and B, a new organic acid glycoside, Sinkiangenorin C, and four known lignin compounds were isolated from the seeds of Ferula sinkiangensis. The structures of these compounds were established by spectroscopic analysis and single-crystal X-ray diffraction. All of the isolated compounds were tested against Hela, K562 and AGS human cancer cell lines. Sinkiangenorin C showed cytotoxic activity against AGS cells with an IC50 of 36.9 μM. PMID:24979220

  3. Stereocontrolled reduction of alpha- and beta-keto esters with micro green algae, Chlorella strains.

    PubMed

    Ishihara, K; Yamaguchi, H; Adachi, N; Hamada, H; Nakajima, N

    2000-10-01

    The stereocontrolled reduction of alpha- and beta-keto esters using micro green algae was accomplished by a combination of the cultivation method and the introduction of an additive. The reduction of ethyl pyruvate and ethyl benzoylformate by the photoautotrophically cultivated Chlorella sorokiniana gave the corresponding alcohol in high e.e. (>99% e.e. (S) and >99% e.e. (R), respectively). In the presence of glucose as an additive, the reduction of ethyl 3-methyl-2-oxobutanoate by the heterotrophically cultivated C. sorokiniana afforded the corresponding (R)-alcohol. On the other hand, the reduction in the presence of ethyl propionate gave the (S)-alcohol. Ethyl 2-methyl-3-oxobutanoate was reduced in the presence of glycerol by the photoautotrophically cultivated C. sorokiniana or the heterotrophically cultivated C. sorokiniana to the corresponding syn-(2R,3S)-hydroxy ester with high diastereo- and enantiomeric excess (e.e.). Some additives altered the stereochemical course in the reduction of alpha- and beta-keto esters. PMID:11129581

  4. Alcohol withdrawal.

    PubMed

    Manasco, Anton; Chang, Shannon; Larriviere, Joseph; Hamm, L Lee; Glass, Marcia

    2012-11-01

    Alcohol withdrawal is a common clinical condition that has a variety of complications and morbidities. The manifestations can range from mild agitation to withdrawal seizures and delirium tremens. The treatments for alcohol withdrawal include benzodiazepines, anticonvulsants, beta-blockers and antihypertensives. Although benzodiazepines are presently a first-line therapy, there is controversy regarding the efficacies of these medications compared with others. Treatment protocols often involve one of two contrasting approaches: symptom-triggered versus fixed-schedule dosing of benzodiazepines. We describe these protocols in our review and examine the data supporting symptom-triggered dosing as the preferred method for most patients in withdrawal.The Clinical Institute Withdrawal Assessment for Alcohol scoring system for alcohol withdrawal streamlines care, optimizes patient management, and is the best scale available for withdrawal assessment. Quality improvement implications for inpatient management of alcohol withdrawal include increasing training for signs of withdrawal and symptom recognition, adding new hospital protocols to employee curricula, and ensuring manageable patient-to-physician and patient-to-nurse ratios. PMID:23128805

  5. Determination of esters in glycerol phase after transesterification of vegetable oil.

    PubMed

    Hájek, Martin; Skopal, Frantisek; Kwiecien, Jirí; Cernoch, Michal

    2010-06-30

    In biodiesel production, glycerol is formed as a side product and it is contained in the glycerol phase. This phase contains (besides glycerol): water, soaps, alcohol, traces of catalyst and glycerides and the remaining esters. In this paper, a new method for the determination of esters in the glycerol phase is introduced. The determination enables the minimization of the losses of biodiesel within the production process. It is based on the gradient RP-LC method (water and acetonitrile) with refractometric detection. The analysis is easy and the samples do not need any treatment (only dilution by water) and has a low detection limit. The results of this method were compared with the results of two other published methods: isocratic HPLC and GC. The disadvantage of these two methods is that they need extensive treatment of the sample, which takes many hours, and they are able to determine only the sum of esters. The new method is reliable, much faster and able to differentiate esters of almost each higher fatty acid (e.g. linoleic, linolenic, strearic alkyl ester) in the glycerol phase. PMID:20685468

  6. Synthesis and Antifeedant Activities of Rosin-Based Esters Against Armyworm.

    PubMed

    Li, Liu; Xinyan, Yan; Yanqing, Gao; Xiao-Ping, Rao

    2016-01-01

    A series of rosin based esters have been synthesized from dehydroabietic acid and maleopimaric acid, respectively. Their structures were confirmed by FT-IR, (1)H NMR, (13)C NMR and single crystal X-ray diffraction. Their antifeedant activities against armyworm were examined by leaf plate method. Methyl ester of dehydroabietic acid and maleopimaric acid were crystallized in orthorhombic system with cell dimensions of a = 26.352 [5] Å, b = 6.1020 [12] Å, c = 11.812 [2] Å and a = 7.9216 [11] Å, b = 11.9912 [16] Å, c = 23.425 [3] Å, respectively. They contained classic tricyclic hydrophenanthrene skeleton. The antifeedant results indicated that most rosin-based esters exhibited significant antifeedant activities at a concentration of 0.01 g mL(-1). Their feeding deterrence values were above 70% after 24h. The antifeedant activities for rosin-based esters increased with the growth of chain length of alcohol except (Ia). Some armyworm were found dead during the antifeedant activity test, by which we speculated that these synthetic rosinbased esters had stomach poison activities against armyworm. PMID:26791346

  7. Amphiphilic Cellulose Ethers Designed for Amorphous Solid Dispersion via Olefin Cross-Metathesis.

    PubMed

    Dong, Yifan; Mosquera-Giraldo, Laura I; Taylor, Lynne S; Edgar, Kevin J

    2016-02-01

    The design of cellulose ether-based amphiphiles has been difficult and limited because of the harsh conditions typically required for appending ether moieties to cellulose. Olefin cross-metathesis recently has been shown to be a valuable approach for appending a variety of functional groups to cellulose ethers and esters, provided that an olefin handle for metathesis can be attached. This synthetic pathway gives access to these functional derivatives under very mild conditions and at high efficiency. Modification of ethyl cellulose by metathesis to prepare useful derivatives, for example, for solubility and bioavailability enhancement of drugs by amorphous solid dispersion (ASD), has been limited by the low DS(OH) of commercial ethyl cellulose derivatives. This is problematic because ethyl cellulose is otherwise a very attractive substrate for synthesis of amphiphilic derivatives by olefin metathesis. Herein we explore two methods for opening up this design space for ether-based amphiphiles, for example, permitting synthesis of more hydrophilic derivatives. One approach is to start with the more hydrophilic commercial methyl cellulose, which contains much higher DS(OH) and therefore is better suited for introduction of high DS of olefin metathesis "handles". In another approach, we explored a homogeneous one-pot synthesis methodology from cellulose, where controlled DS of ethyl groups was introduced at the same time as the ω-unsaturated alkyl groups, thereby permitting complete control of DS(OH), DS(Et), and ultimately DS of the functional group added by metathesis. We describe the functionalized derivatives available by these successful approaches. In addition, we explore new methods for reduction of the unsaturation in initial metathesis products to provide robust methods for enhancing product stability against further radical-catalyzed reactions. We demonstrate initial evidence that the products show strong promise as amphiphilic matrix polymers for amorphous

  8. Identification of β-hydroxy fatty acid esters and primary, secondary-alkanediol esters in cuticular waxes of the moss Funaria hygrometrica.

    PubMed

    Busta, Lucas; Budke, Jessica M; Jetter, Reinhard

    2016-01-01

    The plant cuticle, a multi-layered membrane that covers plant aerial surfaces to prevent desiccation, consists of the structural polymer cutin and surface-sealing waxes. Cuticular waxes are complex mixtures of ubiquitous, typically monofunctional fatty acid derivatives and taxon-specific, frequently bifunctional specialty compounds. To further our understanding of the chemical diversity of specialty compounds, the waxes on the aerial structures of the leafy gametophyte, sporophyte capsule, and calyptra of the moss Funaria hygrometrica were surveyed. Respective moss surfaces were extracted, and resulting lipid mixtures were analyzed by gas chromatography-mass spectrometry (GC-MS). The extracts contained ubiquitous wax compound classes along with two prominent, unidentified classes of compounds that exhibited some characteristics of bifunctional structures. Microscale transformations led to derivatives with characteristic MS fragmentation patterns suggesting possible structures for these compounds. To confirm the tentative structure assignments, one compound in each of the suspected homologous series was synthesized. Based on GC-MS comparison with the authentic standards, the first series of compounds was identified as containing esters formed by β-hydroxy fatty acids and wax alcohols, with ester chain lengths varying from C42 to C50 and the most prominent homolog being C46. The second series consisted of fatty acid esters of 1,7-alkanediols, linked via the primary hydroxyl group, with ester chain lengths C40-C52 also dominated by the C46 homolog. The β-hydroxy acid esters were restricted to the sporophyte capsule, and the diol esters to the leafy gametophyte and calyptra. Based on their homolog and isomer distributions, and the presence of free 1,7-triacontanediol, possible biosynthetic reactions leading to these compounds are discussed. PMID:26553812

  9. Gold-Catalyzed Oxidation of Propargylic Ethers with Internal C-C Triple Bonds: Impressive Regioselectivity Enabled by Inductive Effect

    PubMed Central

    Ji, Kegong; D’Souza, Brendan; Nelson, Jon; Zhang, Liming

    2014-01-01

    Inductive perturbations of C-C triple bonds are shown to dictate the regiochemistry of gold-catalyzed oxidation of internal C-C triple bonds in the cases of propargylic ethers, resulting in highly regioselective formation of β-alkoxy-α,β-unsaturated ketones (up to >50/1 selectivity) via α-oxo gold carbene intermediates. Ethers derived from primary propargylic alcohols can be reliably transformed in good yields, and various functional groups are tolerated. With substrates derived from secondary propargylic alcohols, the development of a new P,N-bidentate ligand enables the minimization of competing alkyl group migration to the gold carbene center over the desired hydride migration; the preferred migration of a phenyl group, however, results in efficient formation of a α-phenyl-β-alkoxy-α,β-unsaturated ketone. These results further advance the surrogacy of a propargyl moiety to synthetically versatile enone function with reliable and readily predictable regioselectivity. PMID:25284890

  10. High absorbing resists based on trifluoromethacrylate-vinyl ether copolymers for EUV lithography

    NASA Astrophysics Data System (ADS)

    Christianson, Matthew D.; Meyer, Matthew M.; Ongayi, Owendi; Valeri, David; Wagner, Michael

    2013-03-01

    Highly sensitive EUV photoresists remain a critical challenge to enable high volume manufacturing with EUV lithography. Chemically amplified resists continue to provide the best sensitivity for EUV photoresists, but the high EUV transparency of most resists continues to waste a large percentage of EUV photons that pass through the resist film without photochemically generating acid. Highly fluorinated polymers have been proposed as more sensitive resist materials because fluorine increases EUV absorption of a material. Thus, methacrylate-like polymers with fluorinated backbones are an attractive possibility for new EUV resist materials. Trifluoromethacrylates are known to undergo free radical polymerization with electron rich comonomers such as vinyl ethers. The resulting polymers have backbone trifluoromethyl groups that enhance the absorption of EUV photons while retaining the potential for solubility change by acid-catalyzed tertiary ester deprotection similar to methacrylate-based chemically amplified resists. Interestingly, copolymerizations of trifluoromethacrylates and vinyl ethers are not particularly sensitive to traditional experimental parameters that influence polymer molecular weight. Instead, we have found that the structure of the vinyl ether comonomer has a profound impact on polymer molecular weight with acyclic vinyl ethers generating very high molecular weight polymers (Mw exceeding 100,000 g/mol) and cyclic vinyl ethers generating very low molecular weight polymers (Mw less than 10,000 g/mol) under similar conditions. Combination of cyclic and non-cyclic vinyl ethers in the monomer feed enables the synthesis of polymers at a desired molecular weight with a narrow polydispersity (PDI less than 2). Initial EUV contrast curves demonstrate potential for highly sensitive photoresists using these backbone-fluorinated polymers. A variety of polymers have been prepared to determine optimum compositions of leaving group, sensitizing, and etch resistant

  11. Metabolism and Cometabolism of Cyclic Ethers by a Filamentous Fungus, a Graphium sp.▿

    PubMed Central

    Skinner, Kristin; Cuiffetti, Lynda; Hyman, Michael

    2009-01-01

    The filamentous fungus Graphium sp. (ATCC 58400) grows on gaseous n-alkanes and diethyl ether. n-Alkane-grown mycelia of this strain also cometabolically oxidize the gasoline oxygenate methyl tert-butyl ether (MTBE). In this study, we characterized the ability of this fungus to metabolize and cometabolize a range of cyclic ethers, including tetrahydrofuran (THF) and 1,4-dioxane (14D). This strain grew on THF and other cyclic ethers, including tetrahydropyran and hexamethylene oxide. However, more vigorous growth was consistently observed on the lactones and terminal diols potentially derived from these ethers. Unlike the case in all previous studies of microbial THF oxidation, a metabolite, γ-butyrolactone, was observed during growth of this fungus on THF. Growth on THF was inhibited by the same n-alkenes and n-alkynes that inhibit growth of this fungus on n-alkanes, while growth on γ-butyrolactone or succinate was unaffected by these inhibitors. Propane and THF also behaved as mutually competitive substrates, and propane-grown mycelia immediately oxidized THF, without a lag phase. Mycelia grown on propane or THF exhibited comparable high levels of hemiacetal-oxidizing activity that generated methyl formate from mixtures of formaldehyde and methanol. Collectively, these observations suggest that THF and n-alkanes may initially be oxidized by the same monooxygenase and that further transformation of THF-derived metabolites involves the activity of one or more alcohol dehydrogenases. Both propane- and THF-grown mycelia also slowly cometabolically oxidized 14D, although unlike THF oxidation, this reaction was not sustainable. Specific rates of THF, 14D, and MTBE degradation were very similar in THF- and propane-grown mycelia. PMID:19581469

  12. Naltrexone for Alcoholism

    MedlinePlus

    MENU Return to Web version Naltrexone for Alcoholism Naltrexone for Alcoholism Is alcoholism a disease? Yes. Most experts agree that alcoholism is a disease, just as high blood pressure, diabetes and ...

  13. Fetal Alcohol Spectrum Disorders

    MedlinePlus

    ... alcohol can cause a group of conditions called fetal alcohol spectrum disorders (FASDs). Effects can include physical and behavioral problems such ... alcohol syndrome is the most serious type of FASD. People with fetal alcohol syndrome have facial abnormalities, ...

  14. IMPROVED OXIDATIVE STABILITY OF ESTOLIDE ESTERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A wide range of commercial and vegetable-based materials were evaluated for their oxidative stability by the rotating bomb oxidative test (RBOT). RBOT values ranged from 13 to 552 minutes. Two estolides, coconut-oleic estolide 2-ethylhexyl ester and oleic estolide 2-ethylhexyl ester, were evaluate...

  15. Sugar Ester Compounds for Arthropod Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sugar esters, also known as acyl sugars or polyol esters, are a class of compounds that are internationally recognized as food additives. They are commonly used in bakery goods, drugs, cosmetics, food packaging plastics, and in other applications because of their surfactant and emulsifying properti...

  16. New cycloartenol esters from Ixora coccinea.

    PubMed

    Ragasa, Consolacion Y; Tiu, Floren; Rideout, John A

    2004-08-01

    The air-dried flowers of Ixora coccinea L. afforded two new cycloartenol esters (1a and 1b), lupeol fatty ester, lupeol, ursolic acid, oleanolic acid, and sitosterol. The structures of 1a and 1b were elucidated by extensive 1D and 2D NMR spectroscopy and MS. PMID:15214483

  17. Biodegradation of Ether Pollutants by Pseudonocardia sp. Strain ENV478

    PubMed Central

    Vainberg, Simon; McClay, Kevin; Masuda, Hisako; Root, Duane; Condee, Charles; Zylstra, Gerben J.; Steffan, Robert J.

    2006-01-01

    A bacterium designated Pseudonocardia sp. strain ENV478 was isolated by enrichment culturing on tetrahydrofuran (THF) and was screened to determine its ability to degrade a range of ether pollutants. After growth on THF, strain ENV478 degraded THF (63 mg/h/g total suspended solids [TSS]), 1,4-dioxane (21 mg/h/g TSS), 1,3-dioxolane (19 mg/h/g TSS), bis-2-chloroethylether (BCEE) (12 mg/h/g TSS), and methyl tert-butyl ether (MTBE) (9.1 mg/h/g TSS). Although the highest rates of 1,4-dioxane degradation occurred after growth on THF, strain ENV478 also degraded 1,4-dioxane after growth on sucrose, lactate, yeast extract, 2-propanol, and propane, indicating that there was some level of constitutive degradative activity. The BCEE degradation rates were about threefold higher after growth on propane (32 mg/h/g TSS) than after growth on THF, and MTBE degradation resulted in accumulation of tert-butyl alcohol. Degradation of 1,4-dioxane resulted in accumulation of 2-hydroxyethoxyacetic acid (2HEAA). Despite its inability to grow on 1,4-dioxane, strain ENV478 degraded this compound for >80 days in aquifer microcosms. Our results suggest that the inability of strain ENV478 and possibly other THF-degrading bacteria to grow on 1,4-dioxane is related to their inability to efficiently metabolize the 1,4-dioxane degradation product 2HEAA but that strain ENV478 may nonetheless be useful as a biocatalyst for remediating 1,4-dioxane-contaminated aquifers. PMID:16885268

  18. Low Temperature Chlorine-Initiated Oxidation of Small-Chain Methyl Esters: Quantification of Chain-Terminating HO2-Elimination Channels.

    PubMed

    Muller, Giel; Scheer, Adam; Osborn, David L; Taatjes, Craig A; Meloni, Giovanni

    2016-03-17

    Cl-initiated oxidation reactions of three small-chain methyl esters, methyl propanoate (CH3CH2COOCH3; MP), methyl butanoate (CH3CH2CH2COOCH3; MB), and methyl valerate (CH3CH2CH2CH2COOCH3; MV), are studied at 1 or 8 Torr and 550 and 650 K. Products are monitored as a function of mass, time, and photoionization energy using multiplexed photoionization mass spectrometry coupled to tunable synchrotron photoionization radiation. Pulsed photolysis of molecular chlorine is the source of Cl radicals, which remove an H atom from the ester, forming a free radical. In each case, after addition of O2 to the initial radicals, chain-terminating HO2-elimination reactions are observed to be important. Branching ratios among competing HO2-elimination channels are determined via absolute photoionization spectra of the unsaturated methyl ester coproducts. At 550 K, HO2-elimination is observed to be selective, resulting in nearly exclusive production of the conjugated methyl ester coproducts, methyl propenoate, methyl-2-butenoate, and methyl-2-pentenoate, respectively. However, in MV, upon raising the temperature to 650 K, other HO2-elimination pathways are observed that yield methyl-3-pentenoate and methyl-4-pentenoate. In each methyl ester oxidation reaction, a peak is observed at a mass consistent with cyclic ether formation, indicating chain-propagating OH loss/ring formation pathways via QOOH intermediates. Evidence is observed for the participation of resonance-stabilized QOOH in the most prominent cyclic ether pathways. Stationary point energies for HO2-elimination pathways and select cyclic ether formation channels are calculated at the CBS-QB3 level of theory and assist in the assignment of reaction pathways and final products. PMID:26910881

  19. Mutagenicity of aromatic glycidyl ethers with Salmonella.

    PubMed

    Rosman, L B; Chakraborty, P K; Messerly, E A; Sinsheimer, J E

    1988-09-01

    6 aromatic glycidyl ethers containing naphthyl, biphenyl or benzylphenyl substituents were synthesized. These epoxides together with the commercially available compounds 2-biphenylyl glycidyl ether were examined for dose-mutagenicity relationships using the plate incorporation Ames test with Salmonella typhimurium strains TA100 and TA1535. Structure-mutagenicity relationships were further examined for these compounds and 3 phenyl glycidyl ethers by concurrent testing at a single dose with strain TA100. Meaningful correlations could not be established for the mutagenicity of these epoxides to their molecular volumes, partition values, nor to their reactivities with the model nucleophile, 4-(4-nitrobenzyl) pyridine. However, it was noted that increased conjugated aromatic unsaturation with its resulting planarity led to increased mutagenicity and that this effect decreased when it was further removed from the epoxide moiety. PMID:3045534

  20. Ethanolysis of rapeseed oil - distribution of ethyl esters, glycerides and glycerol between ester and glycerol phases.

    PubMed

    Cernoch, Michal; Hájek, Martin; Skopal, Frantisek

    2010-04-01

    The distribution of ethyl esters, triglycerides, diglycerides, monoglycerides, and glycerol between the ester and glycerol phase was investigated after the ethanolysis of rapeseed oil at various reaction conditions. The determination of these substances in the ester and glycerol phases was carried out by the GC method. The amount of ethyl esters in the glycerol phase was unexpectedly high and therefore the possibility of the reduction of this amount was investigated. The distribution coefficients and the weight distributions of each investigated substance were calculated and compared mutually. The distribution coefficients between the ester and glycerol phase increase in this sequence: glycerol, monoglycerides, diglycerides, ethyl esters, and triglycerides. Soaps and monoglycerides in the reaction mixture cause a worse separation of ethyl esters from the reaction mixture. The existence of a non-separable reaction mixture was observed also, and its composition was determined. PMID:20005094