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Showing papers on "Transesterification published in 1981"


Journal ArticleDOI
TL;DR: Tetramethylammonium hydroxide in methanol (TMAH) is used to catalyze the transesterification of the fat dissolved in diethyl ether; methyl esters form almost instantly as discussed by the authors.
Abstract: Tetramethylammonium hydroxide in methanol (TMAH) is used to catalyze the transesterification of the fat dissolved in diethyl ether; methyl esters form almost instantly. Glycerin drops out of solution to form a second layer containing the bulk of any free fatty acids present as the TMAH soaps. Gas chromatography of the ether layer gives the fatty acid composition of the glycerides. On injecting the lower layer, the TMAH soaps pyrolyze to form methyl esters. If methanol is added to the flask to solubilize the glycerin and excess base neutralized with methanolic hydrochloric acid, total fatty acid composition can be obtained by chromatographing the resulting solution. -- AATA

166 citations


Patent
06 Mar 1981
TL;DR: In this paper, a method for the enzymatic transesterification useful for modification of a lipid, which comprises continuously or repeatedly contacting an enzyme or an enzyme preparation with a fresh supply of a dried fatty ester substrate such as fats and oils of glycerides.
Abstract: A method for the enzymatic transesterification useful for modification of a lipid, which comprises continuously or repeatedly contacting an enzyme or an enzyme preparation having transesterification activities with a fresh supply of a dried fatty ester substrate such as fats and oils of glycerides. The enzyme or the enzyme preparation has transesterification activities (Kr value) of 0.01 or more as well as lipolytic activities. The enzyme preparation is prepared by dispersing, adsorbing or bonding an enzyme having lipolytic activities in or to a carrier and drying the resulting mixture at an adequately slow initial drying rate to activate or increase the transesterification activities of the enzyme.

77 citations


Patent
Joseph T. Valko1
29 Jul 1981
TL;DR: In this article, a polymeric polyol with a polyester crosslinking agent having at least two beta-alkoxyester groups per molecule is described. And when applied to a substrate and cured in the presence of a transesterification catalyst, give solvent-resistant coatings.
Abstract: Coating compositions comprising a polymeric polyol with a polyester crosslinking agent having at least two beta-alkoxyester groups per molecule are disclosed. The compositions, when applied to a substrate and cured in the presence of a transesterification catalyst, give solvent-resistant coatings.

29 citations


Patent
17 Nov 1981
TL;DR: In this paper, a method of the modification of a fat or oil wherein a mixture (mixture A) containing a glyceride-type fat or oils to be modified (material A) and a fatty acid or a nonglyceride type ester thereof (material B) is selectively transesterified in the presence of a catalyst having a selective transesterification activity (catalyst A); the resulting fat and oil (resultant A), fatty acid and catalyst are recovered from the reaction mixture; and then a hard butter is produced from the resultant A, the improvement
Abstract: In a method of the modification of a fat or oil wherein a mixture (mixture A) containing a glyceride-type fat or oil to be modified (material A) and a fatty acid or a nonglyceride-type ester thereof (material B) is selectively transesterified in the presence of a catalyst having a selective transesterification activity (catalyst A); the resulting fat or oil (resultant A), fatty acid or nonglyceride-type ester thereof (resultant B) and catalyst are recovered from the reaction mixture; and then a hard butter is produced from the resultant A, the improvement comprises hydrogenating a part or all of the resultant B and reusing the hydrogenated product as a part of the mixture A.

26 citations



Patent
Roy L. Pruett1
22 Jun 1981
TL;DR: In this article, a process for converting formic acid esters or transesterification products thereof to carboxylic acids is described, where the formics acid ester of the formula (HCOO) n -R is contacted with a catalytically effective amount of soluble iridium salt and iodine or an iodide as promoter at a temperature of from about 100°C to about 300°C in the presence of an organic solvent containing at least one CARO.
Abstract: A process for converting formic acid esters or transesterification products thereof to carboxylic acids comprising contacting a formic acid ester of the formula (HCOO) n -R where R is aliphatic, cycloaliphatic or aralkyl and n is 1 or 2 with a catalytically effective amount of soluble iridium salt and iodine or an iodide as promoter at a temperature of from about 100°C to about 300°C in the presence of an organic solvent containing at least one carboxylic acid.

21 citations


Patent
27 Apr 1981
TL;DR: An improved aromatic polycarbonate transesterification process comprising reacting a bis(aryl)carbonate and a dihydric phenol in the presence of a transterification catalyst was proposed in this article.
Abstract: An improved aromatic polycarbonate transesterification process comprising reacting a bis(aryl)carbonate and a dihydric phenol in the presence of a transesterification catalyst, the improvement wherein the catalyst contains an aluminum hydride or borohydride group.

19 citations


Patent
18 Feb 1981
TL;DR: In this article, a method for the preparation of a high-quality lower alkyl, e.g. methyl ester of a fatty acid in respects of color and odor which is suitable for the manufacture of high-grade soaps was presented.
Abstract: The invention provides a novel and very efficient method for the preparation of a high-quality lower alkyl, e.g. methyl, ester of a fatty acid in respects of color and odor which is suitable for the manufacture of high-grade soaps even without further purification by salting-out considered indispensable in the prior art processes. The inventive method utilizes a natural oil or fat as the starting material which is subjected to a two-step transesterification with methyl alcohol into a methyl ester of the fatty acid, from which the trace amounts of the colored or chromogenic impurities are removed by admixing an adsorbent. The types of the adsorbent as well as the temperature and the time for the adsorption are important for the effective decolorization. Best results were obtained with a mixture of an activated clay and an active carbon in a specified weight proportion.

16 citations



Journal ArticleDOI
TL;DR: In this article, the effect of various titanium derived catalysts on the polycondensation of bis (4-hydroxybutyl) terephthalate has been studied and the catalytic efficiency of these derivatives is ascribed to their relative hydrolytic stability and the degree of interaction between the carbonyl oxygen and the metal.
Abstract: Monomeric Bis-(4-hydroxybutyl) terephthalate has been synthesized and characterized. Titanium iso-propoxide has been found to be a superior catalyst for transesterification compared to metal acetates. Further polycondensation of Bis (HBT) yields poly (1,4-butylene terephthalate). The effect of various titanium derived catalysts on the polycondensation of Bis (HBT) has been studied. The catalytic efficiency of these derivatives is ascribed to their relative hydrolytic stability and the degree of interaction between the carbonyl oxygen and the metal.

14 citations


Journal ArticleDOI
TL;DR: The hydrolysis and transesterification reactions of furoyl-chymotrypsins display nonlinear Arrhenius plots with no apparent discontinuities and a linear free energy correlation with the Taft polarity constants sigma* and volumes of the attacking alcohols.
Abstract: The hydrolysis and transesterification reactions of furoyl-chymotrypsins display nonlinear Arrhenius plots with no apparent discontinuities. Of a number of models considered, the best explanation assumes a temperature-dependent rapid equilibrium between two forms of acyl-enzyme with differing reactivities. Rate constants for the transesterification of alpha-chymotrypsinyl 2-(5-n-propyl)furoate, after normalization for this equilibrium, display a linear free energy correlation with the Taft polarity constants sigma* and volumes of the attacking alcohols.

Patent
24 Apr 1981
TL;DR: In this article, the present invention is now producing high molecular weight aromatic polycarbonates having Mn (weight-average molecular weight) 20,000 to 180,000 by transesterification of diphenols with Kohlensauredialkylestern in the presence of organotin-IV compounds.
Abstract: Gegenstand der vorliegenden Erfindung ist nun die Herstellung hochmolekularer aromatischer Polycarbonate mit Mn (Gewichtsmittelmolekulargewicht) von 20000 bis 180000, vorzugsweise von 30 000 bis 120000, durch Umesterung von Diphenolen mit Kohlensauredialkylestern in Gegenwart von Organozinn-IV-Verbindungen, die dadurch gekennzeichnet ist, das man die Umesterung in Gegenwart von Phenolen durchfuhrt. The present invention is now producing high molecular weight aromatic polycarbonates having Mn (weight-average molecular weight) 20,000 to 180,000, preferably from 30,000 to 120,000 by transesterification of diphenols with Kohlensauredialkylestern in the presence of organotin-IV compounds, which is characterized in that transesterification in the presence of phenols is carried out.

Patent
14 Apr 1981
TL;DR: In this paper, a process for the preparation of polycarbonates of Mw 20,000 to 180,000 by transesterification of diphenols and carbonic acid dialkyl esters in the presence of organo-tin-IV compounds and a monophenol is described.
Abstract: The invention is directed to a process for the preparation of polycarbonates of Mw 20,000 to 180,000 by transesterification of diphenols and carbonic acid dialkyl esters in the presence of organo-tin-IV compounds and a monophenol.

Patent
11 May 1981
TL;DR: In this article, an improved aromatic polycarbonate transesterification process was proposed, where the catalyst species was pre-formed under equilibration reaction conditions with either a phenol or a bis(aryl) carbonate prior to initiation of the transterification reaction.
Abstract: An improved aromatic polycarbonate transesterification process comprising reacting a bis(aryl)carbonate and a phenol in the presence of a transesterification catalyst containing tetraborate or tetraaluminate anions, the improvement wherein the catalyst species is pre-formed under equilibration reaction conditions with either a phenol or a bis(aryl)carbonate prior to initiation of the transesterification reaction.


Patent
06 Mar 1981
TL;DR: In this paper, a transesterification polymerixation of monomer reactants comprising a bisphenol and a diaryl ester of a dicarboxylic acid in the presence of a basic catalyst is described.
Abstract: Linear aromatic polyesters of bisphenols and dicarboxylic compounds are prepared by transesterification polymerixation of monomer reactants comprising a bisphenol and a diaryl ester of a dicarboxylic acid in the presence of a basic catalyst, wherein basic catalyst, preferably normally solid at 30°C, is introduced into the reaction zone either in liquid form, for example by introducing a normally solid material in molten form or in solution in a solvent, or substantially concurrently with the liquid state reactants. The process avoides substantial heating of reactants in contact with catalyst before onset of the transesterification reaction and provides products of unexpectedly low polydispersity.

Patent
15 Oct 1981
TL;DR: In this paper, a two-step catalyzed process for the preparation of thermoplastic polyphosphonatophenyl ester carbonates is described, comprising first, the production of an aryloxy carbonyloxy-benzoic acid aryls ester and second, its transesterification with a phosphonic acid diphenyl esters and a diphenol is disclosed.
Abstract: A two step catalyzed process for the preparation of thermoplastic polyphosphonatophenyl ester carbonates comprising first, the preparation of an aryloxy carbonyloxy-benzoic acid aryl ester and second, its transesterification with a phosphonic acid diphenyl ester and a diphenol is disclosed.

Patent
28 Oct 1981
TL;DR: In this paper, a process for the preparation of low molecular weight polyesters directly from hydroxypivaldehyde is described, which consists of reacting dry hydroxymivaldehyde with a diester such as dimethyl adipate, dimethyl cyclohexane-1,4-dicarboxylate, and dimethyl terephthalate.
Abstract: The present invention provides a process for the preparation of low molecular weight polyesters directly from hydroxypivaldehyde. The process comprises reacting dry hydroxypivaldehyde with a diester, a multifunctional ester, a diacid, a polyester, or a mixture thereof at a temperature of about 100° C. to 230° C. in the presence of a transesterification catalyst. Optionally, modifying glycols, triols, or polyols may also be added. Suitable catalysts include tetraisopropyl titanate, dibutyltin oxide, lithium hydroxide, and lithium alkoxide, with tetraisopropyl titanate being especially preferred. The reaction is preferably accomplished in two stages by heating the reaction mixture to about 130° C. for about three hours and subsequently heating the reaction mixture to about 190°-230° C. until the reaction is essentially complete. In an especially preferred embodiment, the low molecular weight polyesters are produced by the reaction of hydroxypivaldehyde with a diester such as dimethyl adipate, dimethyl cyclohexane-1,4-dicarboxylate, and dimethyl terephthalate. The low molecular weight polyester product typically exhibits a molecular weight of about 400-2000 and a hydroxyl number of about 100-300.

Patent
06 Mar 1981
TL;DR: In this paper, a transesterification polymerization of bisphenols and dicarboxylic compounds is performed in either a semi-continuous process or in a fully continuous process where a first stage is batchwise or continuously and a second stage is conducted continuously.
Abstract: Linear aromatic polyesters of bisphenols and dicarboxylic compounds are prepared by transesterification polymerization in either a semi-continuous process or in a fully continuous process wherein a first stage is conducted batchwise or continuously and a second stage is conducted continuously, wherein the second stage employs a wiped film reactor, optionally followed by a vented extrusion reactor. The polymerisation is preferably conducted in the presence of a catalyst in liquid form, and further under conditions wherein the catalyst is introduced concurrently with the introduction of liquid phase reactants to avoid substantial heating of the reactants in contact with the catalyst prior to onset of the transesterification reaction. The products of the processes have an unexpectedly low polydispersity.