Showing papers on "Transesterification published in 1978"

A Novel and Rapid Method for the Preparation of Methyl Esters for Gas Chromatography: Application to the Determination of the Fatty Acids of Edible Fats and Oils

Abstract: A rapid, mild, and convenient transesterification of triglycerides was obtained using 0.2 N-methanolic (m-trifluoro-methylphenyl) trimethylammonium hydroxide. The method yielded results comparable to those obtained using methanolic sodium methoxide.

Process for the preparation of aromatic carbonic acid esters

Abstract: Carbonic diesters containing at least one aromatic ester group can be prepared from carbonic diesters containing at least one aliphatic ester group by transesterification using a phenol, titanium dioxide having a surface area of at least 20 m2 /g as determined by the BET method being used as catalyst.

Process for the preparation of carbonic acid bis-diphenol esters of polyester-diols and their use for the preparation of high-molecular segmented polyester/polycarbonates which can be processed as thermoplastics

Abstract: The present invention relates to the transesterification of the carbonic acid aryl esters prepared according to German Published Patent Specification 2,651,639 (which corresponds to US Patent application Ser No 854,174, filed Oct 25, 1977) with an excess of diphenol for the preparation of polyester-diol bis-diphenol carbonate The present invention further relates to the polyester-diol bis-diphenol carbonates obtained according to the invention and their use for the preparation of polyester/polycarbonates and to the polyester/polycarbonates so prepared

Block copolyesters which crystallize rapidly

Abstract: The current invention is concerned with block copolyesters of low glass transition temperature segments and ethylene glycol based polyester segments linked together by carboxylic acid ester groups and special diols, and a process for preparing these copolyesters. These copolyesters display molded resin properties similar to polyethylene terephthalate but crystallization behavior similar to polybutylene terephthalate, i.e. they have high strength and superior solvent resistance, but they also crystallize rapidly. They are made by subjecting low glass transition temperature (less than 0° C.) polymers with carboxyl, hydroxyl or reactive ester end groups to esterification or transesterification conditions with ethylene glycol based polyester segments having a minimum intrinsic viscosity of 0.2 dl/g and special diols having four to ten carbon atoms with 3 or 4 carbon atoms between the hydroxyl groups in the presence of appropriate catalysts. In a preferred embodiment, the three components are subject to melt homogenization in an extruder and the solidified extrudate is subject to a solid state polycondensation reaction.

Transesterification of alkyl phosphinates

Abstract: Alkyl esters of phosphinic acid [HOP(O)H2] undergo rapid transesterification at room temperature with primary, secondary, and tertiary aliphatic alchols but not with phenol; trimethyl phosphate, dimethyl phosphonate, and the methyl esters of substituted phosphinic acids do not react under these conditions.

Preparation of alkyl mercaptocarboxylate/dialkyl thiodicarboxylate mixture using sulfur and/or water cocatalyst

Abstract: An olefinically unsaturated alkyl carboxylate is reacted with hydrogen sulfide in the presence of a lower alkanol using an addition catalyst with water and/or sulfur cocatalyst to give an alkyl mercaptocarboxylate/dialkyl thiodicarboxylate mixture having a high proportion of the mercaptocarboxylate If sulfur is contained in the cocatalyst, dialkyl dithiodicarboxylates are also formed The resulting mixture on transesterification with a poly(oxyalkylene)-polyol gives a poly(oxyalkylene)-polyester-poly(monosulfide)-polythiol or a poly(oxyalkylene)-polyester-poly(monosulfide)-poly(disulfide)-polythiol having a good balance of properties

Manufacture of esters

Abstract: m-Phenoxybenzyl esters of carboxylic acids are prepared from the methyl or ethyl esters of the acids by reaction of the latter with m-phenoxybenzyl alcohol in the presence of a transesterification catalyst of the formula Ti(O.CO.R) 2 Z 2 in which R is a hydrocarbon radical and Z is a bidentate chelate compound.

Glycol and silicate-based surfactant composition for stabilizing polyurethane foam

Abstract: A novel glycol and silicate-based surfactant composition is prepared by (a) obtaining a silicate-based component by a selective process involving (i) reaction of silicon tetrahalide with water and alcohol followed by (ii) transesterification with a polyether alcohol, and (b) subsequently combining the silicate-based component with glycols and/or polyglycol ethers. The resulting surfactant composition is utilized as a stabilizer in the production of polyurethane foam.

Continuous alcohol prodn. by catalytic transesterification - using distillation column as reactor, esp. for diol prodn.

Abstract: Prepn. of alcohols (I) by catalytic transesterification, where (I) has a higher b.pt. than the reactant alcohol (Ia) (and opt. than the ester components), comprises supplying the feed ester, excess (Ia) and catalyst to the upper part of a distillation column, then recovering reaction prods. from the bottom or top of the column. Pref. where the catalyst is a solid it may be used as column packing. The method is esp. for making diols from corresp. esters by reaction with 1-3C monovalent alcohols, specifically prodn. of 1,4-butanediol or 1,4-butenediol from corresp. acetates and methanol. Process can be operated continuously.

Method of producing polyesters

Abstract: New method of manufacturing polyesters and copolyesters having a base of aromatic diacids and condensation diols having at least 3 carbon atoms. This method, carried out in the presence of an organic titanium derivative, by transesterification between an alkyl ester of the aromatic diacid and the diol, and then polycondensation, is characterized by the addition, during the polycondensation stage, of 0.001 to 1% by weight of a nonvolatile amine, based on the weight of polymer. The polymers obtained may be transformed into threads, fibers, films or molded objects.

Process for preparing fast dyeings and prints on cellulose fiber materials and their mixtures with synthetic fibers

Abstract: Fast colorations can be obtained on cellulose materials with disperse dyestuffs containing ester groups when heat-fixation occurs in the presence of aliphatic alcohols, amines or aminoalcohols. Probably a transesterification and/or amide formation leading to significantly higher molecular weight of the dyestuffs are responsible for the good fastness properties of the colorations.

Neopentyl polyol ester and lubricant comprising it

Abstract: NEW MATERIAL:A neopentyl polyol ester synthesized from neopentyl polyol, a mixed fatty acid consisting of A) 3,5,5-trimethylhexanoic acid and B) a 4W18C saturated straight-chain fatty acid in a weight ratio of A to B of 90:10W10:90. EXAMPLE: An ester synthesized from trimethylolpropane, 3,5,5-trimethylhexanoic acid, and lauric acid. USE: Base oil. High oxidative stability and forming an extremely small amount of carbonaceous materials. PROCESS: A neopentyl polyol ester, 3,5,5-trimethylhexanoic acid, and a 4W18C saturated straight-chain fatty acid undergo general esterification or transesterification to give the desired compound. COPYRIGHT: (C)1980,JPO&Japio

Studies of Thermal Transesterification of Phenylurethane by High Pressure Liquid Chromatograph

Abstract: Thermal transesterification of phenylurethane with n-octanol was carried out in DMSO. It was found that the reaction followed first-order kinetics with an average rate constant of 8.630 × 10−5 sec −1at 140°C. High pressure liquid chromatograph technique was employed to analyze chemical species in the course of the reaction. The reaction obeyed Arrhenius equation closely between 133°C and 155°C with activation energy of 29.6 kcal/mole and entropy of activation of −8.2 cal/mole deg at 140°C. An intramolecular cyclic intermediate mechanism was proposed for this reaction.

Transesterification of alkyl phosphinates

Abstract: Alkyl esters of phosphinic acid [HOP(O)H2] undergo rapid transesterification at room temperature with primary, secondary, and tertiary aliphatic alchols but not with phenol; trimethyl phosphate, dimethyl phosphonate, and the methyl esters of substituted phosphinic acids do not react under these conditions.