Showing papers on "Transesterification published in 1986"
TL;DR: This one-step direct transesterification procedure carried out in methanol-benzene 4:1 with acetyl chloride is superior to currently used methods not onlyBecause of its simplicity and speed, but also because of its added precision.
2,315 citations
TL;DR: In this article, the effects of the type of alcohol, 1-butanol or methanol (MeOH), molar ratio of alcohol to SBO, type and amount of catalyst, and reaction temperature on rate constants and kinetic order were examined.
Abstract: Transesterification of soybean oil (SBO) and other triglycerides with alcohols, in the presence of a catalyst, yields fatty esters and glycerol. Di- and monoglycerides are intermediates. Reactions are consecutive and reversible. Rate constants have been determined for each reaction with a computerized kinetic program. The effects of the type of alcohol, 1-butanol or methanol (MeOH); molar ratio of alcohol to SBO; type and amount of catalyst; and reaction temperature on rate constants and kinetic order were examined. Forward reactions appear to be pseudo-first order or second order depending upon conditions used. Reverse reactions appear to be second order. At a molar ratio of MeOH/SBO of 6:1, a shunt reaction was observed. Energy of activation was determined for all forward and reverse reactions under a variety of experimental conditions from plots of log k vs 1/T. Values ranged from 8–20 kcal/mol.
1,215 citations
TL;DR: In this paper, a distannoxane-catalyzed transesterification reaction has been developed which affords various types of esters under very mild conditions and is applied to the stereo and regioselective synthesis of trisubstituted α,β-unsaturated carboxylic acids.
141 citations
138 citations
Patent•
18 Feb 1986TL;DR: In this paper, a process for manufacturing a composition of fatty acid esters useful as gas oil substitute motor fuel, said composition containing at least one hydrated ethyl alcohol was described.
Abstract: The invention concerns a process for manufacturing a composition of fatty acid esters useful as gas oil substitute motor fuel, said composition containing at least one hydrated ethyl alcohol. The process comprises: (A) A first acid transesterification step in the presence of at least one aliphatic, linear or branched monoalcohol of 1 to 5 carbon atoms, consisting at least partly of hydrated ethyl alcohol containing 1 to 60% by weight of water, said step leading to the formation of a phase mainly containing ethyl esters after removal of the produced glycerol phase, (B) A second step wherein the initial free acidity or that formed during the first step in the phase containing the esters is decreased to a value at most equal to about 2%; and (C) A third step of basic transesterification of the phase resulting from step B, in the presence of at least one aliphatic, linear or branched monoalcohol of 1 to 5 carbon atoms, with the recovery of the so-formed ester composition. The composition of the invention can be used for combustion in Diesel engines.
103 citations
TL;DR: In this article, a rapid quantitative capillary gas Chromatographic method was developed for studying transesterification of soybean oil (SBO) to fatty esters, and the effect of carrier gas flow on reproducibility was determined.
Abstract: A rapid quantitative capillary gas Chromatographic method has been developed for studying transesterification of soybean oil (SBO) to fatty esters. Standard solutions containing methyl linoleate, mono- , di- and trilinolein were analyzed with a 1.8 m X 0.32 mm SE- 30 fused silica column. The effect of carrier gas flow on reproducibility was determined. Prior to analysis, mono- (MG) and diglycerides (DG) were silylated with N,O- bis(trimethylsilyl) trifluoroacetamide.Tridecanoin was used as an internal standard. From plots of area and weight relationships, slopes and intercepts for all four compound classes were determined. Agreement between the measured and calculated compositions of the standard solutions was good; the overall standard deviation was 0.4. Slopes and intercepts also were determined for SBO and its methyl and butyl esters. Complete separation of ester, MG, DG and triglyceride was obtained in 12 min by temperature programming from 160 to 350 C. This method of analysis gave excellent results when used in a kinetic study of SBO transesterification.
99 citations
TL;DR: In this article, the main reaction is an exchange reaction identical to that occurring in bisphenol-A polycarbonate-poly(butylene terephthalate) mixtures, probably resulting from the instability of the ethylene carbonates produced by transesterification.
Abstract: This paper is devoted to the study of the reactions taking place in molten bisphenol-A polycarbonate-poly(ethylene terephthalate) mixtures. The analysis of the reaction products by infrared, proton and nuclear magnetic resonance spectroscopy, and by thermogravimetric analysis shows that the main reaction is an exchange reaction identical to that occurring in bisphenol-A polycarbonate-poly(butylene terephthalate) mixtures. However, some other reactions consecutive to this exchange reaction also take place, probably resulting from the instability of the ethylene carbonates produced by transesterification.
95 citations
TL;DR: Asymmetric hydrolysis, ester interchange and ester formation were carried out for menthol resolution with Candida cylindracea lipase in this article under emulsified conditions with water soluble enzyme and in organic medium with an insoluble enzyme preparation.
92 citations
73 citations
47 citations
TL;DR: Aromatic and α,β-unsaturated methyl esters undergo efficient transesterification at ambient temperature or below with primary, secondary, or tertiary alcohols in the presence of butyl-lithium in tetrahydrofuran solution as mentioned in this paper.
Abstract: Aromatic and α,β-unsaturated methyl esters undergo efficient transesterification at ambient temperature or below with primary, secondary, or (particularly) tertiary alcohols in the presence of butyl-lithium in tetrahydrofuran solution.
Patent•
04 Feb 1986
TL;DR: Alkyl esters are prepared from fats and oils and glyceride-containing fractions thereof by mixing a solution of the fat or oil in an inert organic solvent with an alkanol in the presence of a lipase and water.
Abstract: Alkyl esters are prepared from fats and oils and glyceride-containing fractions thereof by mixing a solution of the fat or oil in an inert organic solvent with an alkanol in the presence of a lipase and water Usually, the oil, alkanol and solvent are mixed together and the mixture added to a paste or suspension of the lipase in the water The process has particular application to vegetable oils and especially to palm oil Preferably the amount of water and alkanol is at least 2 litres per kilogram of oil and the inert solvent, eg petroleum ether, is used in similar amounts
TL;DR: In this paper, the reaction of diglycidyl ether of bisphenol A with methacrylic acid was carried out in the presence of an amine catalyst (imidazole) or a chromium chelate (chromium diisopropylsalicylate).
Abstract: The reaction of diglycidyl ether of bisphenol A with methacrylic acid was carried out in the presence of an amine catalyst (imidazole) or a chromium chelate (chromium diisopropylsalicylate). The resin products were analyzed by gel permeation chromatography and13C nuclear magnetic resonance spectroscopy. With both catalysts the reaction is characterized by an isomerization of the hydroxy-ester. The imidazole-catalyzed reaction product gave transesterification species in addition to isomerization product whereas these were absent with the chromium derivative catalyst.
Patent•
06 Jun 1986
TL;DR: In this article, a new transesterification catalyst comprising an epoxide and a non-acidic nucleophilic onium salt was proposed for low-temperature cure coatings.
Abstract: A new transesterification catalyst comprises an epoxide and a non-acidic nucleophilic onium salt. Coating compositions having hydroxyl functional resin components and carboxylic ester components adapted for curing by transesterification following application to a substrate are formulated with in-situ formed cure catalyst comprising a non-acidic nucleophile and an epoxide-to-product coatings that readily cure by transesterification. Such coatings including polyesters, polyepoxides, and polyacrylates are useful in formulating high solids coatings and powder coatings having exceptional physical properties. Extremely low-temperature cure coatings were obtained by transesterifying mixtures of polyols and polymeric esters having multiple activated ester linkages having the structure ##STR1## wherein R' is lower alkyl and Y is --OH and O-alkyl radicals. These coatings provide low-temperature cure coatings for paper, plastic, and wood in addition to metal substrates.
Patent•
07 Mar 1986
TL;DR: In this paper, a slurry is formed by mixing a dicarboxylic acid (eg, terephthalic acid) containing a P compound (e.g., phosphoric acid) in an amount to provide a polyester of an intrinsic viscosity of 6W07.
Abstract: PURPOSE: To produce a polyester for a transparent film excellent in electrostatic castability, by reacting a dicarboxylic acid containing a P compound with a bis(β-hydroxyethyl) terephthalate containing a glycol CONSTITUTION: A slurry formed by mixing a dicarboxylic acid (eg, terephthalic acid) containing a P compound (eg, phosphoric acid) in an amount to provide 003×10 -3 W20×10 -3 mol of P per mol of the dicarboxylic acid with a glycol (eg, ethylene glycol) at a molar ratio of 1:105W1 is added continuously or intermittently to bis(β-hydroxyethyl) terephthalate (oligomer) to perform transesterification at 240W280°C and normal pressure or a pressure of 03W30kg/cm 2 to a degree of esterification of 90W98% A vivalent metal compound (eg, zinc acetate) in an amount equivalent to 008×10 -3 W20×10 -3 mol of the metal of the metal per mol of the dicarboxylic acid is added to the reaction system, and the reaction mixture is polycondensed in the presence of a polycondensation catalyst (eg, Sb 2 O 3 ) to obtain a polyester of an intrinsic viscosity of 06W07 COPYRIGHT: (C)1987,JPO&Japio
Patent•
17 Jan 1986
TL;DR: In this article, the preparation of esters of a non-reducing sugar like sucrose and one or more fatty acids by transesterification is described, where a worm shaft reactor operating at elevated temperature and pressure and a second one operating at reduced pressure and elevated temperature is used.
Abstract: Method for the preparation of esters of a non-reducing sugar like sucrose and one or more fatty acids by transesterification of a non-reducing sugar with one or more fatty acid esters in at first a worm shaft reactor operating at elevated temperature and pressure and then in a second reactor operating at reduced pressure and elevated temperature. Such esters of a non-reducing sugar and fatty acids, in particular the monoesters and diesters are valuable solid surfactants, which are non-toxic, odorless, tasteless, non-irritating to the skin and hydrolyze in the human and animal tract to normal good products.
Patent•
21 Apr 1986TL;DR: Solid sodium carbonate and/or sodium hydrogen carbonate is used as heterogeneous solid catalyst(s) in the transesterification of de-acidified and anhydrous fatty acid glycerides as mentioned in this paper.
Abstract: Solid sodium carbonate and/or sodium hydrogen carbonate is/are used as heterogeneous solid catalyst(s) in the transesterification of de-acidified and anhydrous fatty acid glycerides, more especially from fats and/or oils of natural origin, with lower monofunctional alcohols to form fatty acid alkylesters and glycerol.
TL;DR: The kinetics of tetrabutyl titanate catalyzed transesterification of dimethyl terephthalate (DMT) with 1,4-butanediol (BD) was investigated in this article.
Abstract: The kinetics of tetrabutyl titanate catalyzed transesterification of dimethyl terephthalate (DMT) with 1,4-butanediol (BD) is investigated. Detailed analysis of experimental data indicates that equal reactivity hypothesis for functional groups is valid for [BD]/[DMT] molar ratios greater than 2 up to 75% conversion. Effects of reaction temperature and catalyst concentration are also discussed.
TL;DR: Fractional recrystallization of diastereomeric 2,4,6-triisopropylpheny1 4′-(l-menthyloxycarbonyl) selenoxide gave optically pure (−)-selenoxide as discussed by the authors.
Abstract: Fractional recrystallization of diastereomeric 2,4,6-triisopropylpheny1 4′-(l-menthyloxycarbonyl)phenyl selenoxide gave optically pure (−)-selenoxide. Transesterification of this diastereomerically pure (−)-selenoxide with methanol gave enantiomeric (−)-2,4,6-triisopropylphenyl 4-′-(methoxycarbonyl)phenyl selenoxide in 88.1% optical purity.
Patent•
18 Feb 1986TL;DR: In this paper, a mixture of tetrahydrofuran and 1,4-butanediol at a predetermined mole ratio is produced by the hydrogenation of dimethylsuccinate in the presence of a copper chromite catalyst.
Abstract: Mixtures of tetrahydrofuran and 1,4-butanediol at a predetermined mole ratio are produced by the hydrogenation of dimethylsuccinate in the presence of a copper chromite catalyst wherein said ratio is controlled by conducting the hydrogenation within a particular temperature range. Methanol is added to the ester feed to increase conversion and reduce transesterification. Tetrahydrofuran and 1,4-butanediol are separated from a mixture which also contains water and methanol by a series of distillations including a superatmospheric distillation.
TL;DR: In this paper, 2(2,4-Dihydroxyphenyl) H-4-hydroxybenzotriazole and 2 (2, 4-dihydroxy-phenyl) 2H-1, 3-di(4)-hydroxymhenyl (2H-2H)2HbenzOTriazoles were incorporated into examples of typical aliphatic or aromatic polyesters.
Abstract: 2(2,4-Dihydroxyphenyl) H-4-hydroxybenzotriazole and 2(2,4-dihydroxy-phenyl)2H-1,3-di(4-hydroxybenzotriazole) were incorporated in amounts of 1 to 10 mol% into examples of typical aliphatic or aromatic polyesters, either by direct synthesis from the monomers or by transesterification from already prepared polyesters. The polyesters showed UV spectra typical for the 2(2-hydroxyphenyl)2H-benzotriazole unit in amounts approximately corresponding to the feed composition. Some complications in the direct incorporation of dihydroxy-2(2-hydroxyphenyl)2H-benzotriazoles into polyesters were encountered when the diacid chloride method was used for the preparation of the polyesters; branched and crosslinked polyesters were obtained.
TL;DR: In this article, the structure and derivation of classic silicone fluids are described, giving the reactions for the production of dimethyl fluids by Miiller-Rochow synthesis, polymerisation, direct synthesis, hydrosilylation, and transesterification.
Abstract: This paper describes the structure and derivation of ‘classical’ silicone fluids, giving the reactions for the production of dimethyl fluids by Miiller-Rochow synthesis, polymerisation, direct synthesis, hydrosilylation, and transesterification. The properties of siloxanes are described, and the applications of silicone fluids and compounds are discussed in relation to their properties, particularly insolubility in water, viscosity-temperature characteristics, and dielectric properties.
Patent•
11 Jul 1986
TL;DR: In this paper, a methyl methacrylate is efficiently transesterified with a heavy alcohol in the presence of defined amounts of a lithium catalyst incrementally added to the reaction medium, and an azeotrope-forming compound which forms, together with the methanol produced, an aZEOTrope distilling at a temperature of less than about 60°C.
Abstract: Methyl methacrylate is efficiently transesterified with a heavy alcohol in the presence of (i) defined amounts of a lithium catalyst incrementally added to the reaction medium, and (ii) an azeotrope-forming compound which forms, together with the methanol produced, an azeotrope distilling at a temperature of less than about 60° C.
Patent•
23 Dec 1986
TL;DR: In this article, the authors present a method of pre-preparing organic carbonate by transesterification in the presence of a CATALYST TRANSESTERIFICATION based on IONIC SALT.
Abstract: METHOD OF PREPARATION OF ORGANIC CARBONATE BY TRANSESTERIFICATION A DIESTER OF CARBON DIOXIDE AND AT LEAST AN ALCOHOL HEAVIER THAN THAT THOSE FORMS BY TRANSESTERIFICATION IN THE PRESENCE OF A CATALYST TRANSESTERIFICATION BASED IONIC SALT BASIC CHARACTERIZED IN THAT THAT OPERATION IS MADE TRANSESTERIFICATION ALSO IN THE PRESENCE OF COMPOUND COMPLEXING SOLUBILISING LIKELY AT LEAST PARTIALLY IN SALT SUCH REACTION MEDIUM BY ITS complexation TION AND AT LEAST PARTIALLY DISSOCIATING SAID SALT. THIS METHOD IS PARTICULARLY WELL SUITED TO PREPARATION AND DIALLYL Carbonate bis (allyl carbonate) Diethylene Glycol OF.
TL;DR: Diagramme de phases de poly(bisphenol E isophtalate-co-naphtalate) dans un ester phenyle p-substitue de l'acide terephtalique, bis(p-methoxycarbonyl) phenyl) terenylate.
Abstract: Diagramme de phases de poly(bisphenol E isophtalate-co-naphtalate) dans un ester phenyle p-substitue de l'acide terephtalique, bis(p-methoxycarbonyl) phenyl) terephtalate
TL;DR: In this paper, a polymeres lineaires avec des groupes absorbants UV du titre par synthese directe a partir d'absorbants UV, bisphenol A et carbonate de diphenyle, ou par transesterification
Abstract: Preparation de polymeres lineaires avec des groupes absorbants UV du titre par synthese directe a partir d'absorbants UV, bisphenol A et carbonate de diphenyle, ou par transesterification
TL;DR: It is proposed that the Ser-Phe combination present in L 16, L11 and L6 is involved in transesterification in addition to the single histidine in L16, which appears to be important in the catalysis of peptide bond formation andTransesterification.
Abstract: L16 exhibits both peptide bond and transesterification activities when reconstituted into 2 M LiCl core particles. L6 and L11, when reconstituted in a similar manner in the absence of L16, manifest significant transesterification activity. Both L6 and L11 enhance the transesterification activity of L16; L11 being more active than L6 in this respect. However, both L6 and L11 have minimal effect on peptide bond formation when reconstituted with L16 at concentrations more than 2.5 M equivalents. Both L6 and L11 exhibit a differential effect on transesterification.
The affinity-labelling agents, like PhCH2SO2F, diisopropylfluorophosphate and ethoxyformic anhydride, have been used to explore the role of residues in peptide bond formation and transesterification. It is proposed that the Ser-Phe combination present in L16, L11 and L6 is involved in transesterification in addition to the single histidine in L16. The single histidine in L16 appears to be important in the catalysis of peptide bond formation and transesterification.
Patent•
06 Feb 1986TL;DR: In this paper, sterically hindered polyesters are used as hardeners and resin binders for high solids coatings, using dialkyl 2,2-dimethyl-4-methyleneglutarate.
Abstract: Polyesters containing tertiary ester linkages and pendant methylene unsaturation along the polymer chain are prepared from dialkyl 2,2-dimethyl-4-methyleneglutarate by transesterification with sterically structured polyols, preferably neopentyl glycol. The resultant sterically hindered polyesters are useful as hardeners and resin binders for high solids coatings.
TL;DR: There are two active forms of acyl-alpha-chymotrypsin and it is proposed that formation of the tetrahedral intermediate is the rate-limiting step in both hydrolysis and transesterification and that the position of the transition state in thetransesterification is closer to the starting enzyme ester while that for the hydrolytic reaction is close to the tetRAhedral intermediate.
Abstract: We have measured, by permeable membrane/mass spectrometry, the 16O/18O, 12C/13C, and solvent H2O/D2O kinetic isotope effects (kie) associated with acyl-alpha-chymotrypsin hydrolysis and transesterification. The hydrolysis of alpha-chymotrypsinyl 2-furoate has a 12C/13C kie of approximately 1.06. Transesterification of the same acyl enzyme shows 16O/18O, 12C/13C, and solvent H2O/D2O kinetic isotope effects of 1.015 (0.003), 1.01-1.02, and 2.226 (0.007), respectively. From the temperature independence of the 16O/18O transesterification kinetic isotope effect and kinetic data reported elsewhere [Wang, C.-L. A., Calvo, K. C., & Klapper, M. H. (1981) Biochemistry 20, 1401-1408], we conclude that there are two active forms of acylchymotrypsin. We also propose that formation of the tetrahedral intermediate is the rate-limiting step in both hydrolysis and transesterification and that the position of the transition state in the transesterification is closer to the starting enzyme ester while that for the hydrolytic reaction is closer to the tetrahedral intermediate. These results are discussed in terms of reaction mechanism plasticity.
Patent•
14 Jan 1986
TL;DR: In this paper, the preparation of esters of a non-reducing sugar like sucrose and one or more fatty acids by transesterification is described, where a worm shaft reactor operating at elevated temperature and pressure and a second one operating at reduced pressure and elevated temperature are used.
Abstract: @ Method for the preparation of esters of a non-reducing sugar like sucrose and one or more fatty acids by transesterification of a non-reducing sugar with one or more fatty acid esters in at first a worm shaft reactor operating at elevated temperature and pressure and then in a second reactor operating at reduced pressure and elevated temperature. Such esters of a non-reducing sugar and fatty acids, in particular the monoesters and diesters are valuable solid surfactants, which are non-toxic, odourless, tasteless, non--irritating to the skin and hydrolyse in the human and animal tract to normal good products.