Showing papers on "Transesterification published in 1975"
Patent•
30 Sep 1975TL;DR: In this article, diaryl carbonates are prepared from dialkyl aryl carbonate and phenolic compounds by transesterification in the presence of a transterification catalyst at 60°-320° C in an apparatus composed of two columns.
Abstract: Diaryl carbonates are prepared from dialkyl carbonates and phenolic compounds by transesterification in the presence of a transesterification catalyst at 60°-320° C. in an apparatus composed of two columns in a continuous procedure. In the first column, the starting materials form essentially the associated alkyl aryl carbonate, from which, in the second column, the diaryl carbonate is produced by further transesterification and disproportionation.
62 citations
TL;DR: In this article, the rate constant of transesterification of DMT with ethylene glycol (EG) in the presence of various metal compounds as catalysts at 197°C, calculated from the quantity of formed methanol, was used to evaluate each metal compound in its catalytic activity.
61 citations
TL;DR: The mechanism of esterification of silanol groups of silica gel with alcohols and the hydrolysis or transesterification of the surface esters was investigated using optically active secondary alcohols or alcohols with different alkoxy groups as mentioned in this paper.
41 citations
Patent•
11 Dec 1975TL;DR: In this article, an alkylation, reduction and transesterification process for the preparation of ester substituted phenols is described, and the products are useful as antioxidants and may be prepared in high yields and with a high degree of purity.
Abstract: This invention comprises an alkylation, reduction and transesterification process for the preparation of ester substituted phenols. The products are useful as antioxidants and may be prepared in high yields and with a high degree of purity.
32 citations
Patent•
03 Nov 1975
TL;DR: In this paper, mixed ester products obtained by treatment of a triglyceride under transesterification conditions with a polyoxyalkylene glycol and a high molecular weight dicarboxylic acid, such as polymer acids, are useful metal working fluids.
Abstract: Mixed ester products obtained by treatment of a triglyceride under transesterification conditions with a polyoxyalkylene glycol and a high molecular weight dicarboxylic acid, such as polymer acids, are useful metal working fluids. The modified triglycerides exhibit enhanced thermal stability and can be used either in neat form or in solution and are readily compatible with water to provide stable aqueous emulsions and dispersions having superior lubrication properties.
20 citations
Patent•
12 Sep 1975
TL;DR: In this article, a mixture of saturated and unsaturated fatty acid esters is obtained, which is fractionated by vacuum distillation, and then fed into the second transesterification.
Abstract: Liquid edible oil is produced from palm oil or similar oils and fats. The fatty acid residues are redistributed between two batches of the starting oil by transesterification with (C 1 -C 3 )-alkanol esters of fatty acids. One batch is reacted with unsaturated fatty acid esters (first transesterification) and is thereby enriched with unsaturated fatty acid radicals, while the other batch is reacted with saturated esters (second transesterification) and is thereby enriched with saturated fatty acid radicals. In both transesterifications a mixture of saturated and unsaturated fatty acid esters is obtained, which is fractionated by vacuum distillation. The saturated esters obtained from the first transesterification are fed into the second one and, conversely, the unsaturated esters obtained from the second transesterification are fed into the first one.
17 citations
Patent•
29 Dec 1975
TL;DR: Complexes of stannous carboxylate and tetraalkyl titanate are effective esterification and transesterification catalysts as discussed by the authors, and they can be used as catalysts.
Abstract: Complexes of stannous carboxylate and tetraalkyl titanate are effective esterification and transesterification catalysts
15 citations
TL;DR: In the presence of an alcohol, oxalic acid esters undergo diazomethane-catalyzed transesterification as mentioned in this paper, in which they undergo transesterization under mild reaction conditions.
Abstract: In the presence of an alcohol, oxalic acid esters undergo diazomethane-catalyzed transesterification. Under mild reaction conditions, esters of homologous dicarboxylic acids and other polycarboxyli...
9 citations
TL;DR: In this article, a method for the micro determination of acetyl groups is described which combines features of the known transesterification and the hydroxamate methods, which is distilled off and determined photometrically as the iron complex of the acethydroxamic acid.
8 citations
Patent•
04 Dec 1975
TL;DR: In this article, a process for the preparation of linear aliphatic polycarbonates having terminal hydroxyl groups is carried out in two stages: I. in the first stage, the transesterification is performed in the presence of a basic catalyst at a temperature below 140° C, and Ii in the second stage, after complete destruction of the basic catalyst, the transformation is completed by an acid catalyst at between 200° and 250° C.
Abstract: A process for the preparation of linear aliphatic polycarbonates having terminal hydroxyl groups is carried out in two stages: I. in the first stage, the transesterification is carried out in the presence of a basic catalyst at a temperature below 140° C, and Ii. in the second stage, after complete destruction of the basic catalyst, the transesterification is completed in the presence of an acid catalyst at a temperature of between 200° and 250° C. The polycarbonate-diols obtained are useful for the preparation of polyurethane elastomers which are resistant to hydrolysis.
7 citations
Patent•
05 Aug 1975
TL;DR: In this paper, a process for the manufacture of wire insulation varnish resins suitable for application from the melted state is described, which comprises: 1. Contacting a lower alkyl ester of terephthalic acid with tris-(hydroxyethyl)-isocyanurate and ethylene glycol in the presence of a trans esterification catalyst, and 2. Polycondensing the reaction mixture until a resin is formed having a consistency at 140° to 160° C.
Abstract: A process for the manufacture of wire insulation varnish resins suitable for application from the melted state which comprises: 1. Contacting a lower alkyl ester of terephthalic acid with tris-(hydroxyethyl)-isocyanurate and ethylene glycol in the presence of a trans esterification catalyst in the presence of 0.3 to 1.5% of an alcoholate of titanium, vanadium or zirconium and effecting transesterification under transesterification conditions; 2. Contacting the transesterification product from step 1 with trimellitic acid anhydride under esterification conditions to further effect esterification, but prior to completion of such esterification; 3. Adding to the reaction mixture 4,4'-diaminodiphenyl methane in an amount such that the molar ratio of trimellitic acid derived from trimellitic acid anhydride to said 4,4'-diaminodiphenylmethane is 2 to 1; and 4. Polycondensing the reaction mixture until a resin is formed having a consistency at 140° to 160° C such that it can be applied to a wire substrate in melted form.
TL;DR: The catalytic effects of the macroreticular cation exchange resin Amberlyst 15 (H+) on the transesterification of dimethyl terepbthalate with ethylene glycol have been investigated in a batch reactor and at the temperature of 146°C with the aid of extensive chemical analysis.
Abstract: The catalytic effects of the macroreticular cation exchange resin Amberlyst 15 (H+) on the transesterification of dimethyl terepbthalate with ethylene glycol have been investigated in a batch reactor and at the temperature of 146°C with the aid of extensive chemical analysis. The resin exhibited significant intraparticle diffusion effects for the disappearance of dimethyl terephthalate and promoted the dehydration and subsequent etherification and polymerization reactions of ethylene glycol to a very significant extent. The side reactions of ethylene glycol rendered the transesterification process in the presence of Amberlyst 15 (H+) inefficient.
On a etudie les effets catalytiques de la resine macroreticulaire et echangeuse de cations Amberlyst 15 (11+) sur la transesterification du terephtalate dimethyle avec le glycol ethylenique; on a fait cette etude dans un reacteur discontinu a 146°C avec l'aide d'une analyse chimiquc poussee. La resine a presente des effets importants de diffusion entre les particules relativement a la disparition du terephtalate dimethyle et a favorise, a un degre tres important, la deshydratation, puis les reactions d'etherification et de polymerisation de l'ethylene glycol. Les reactions secondaires du glycol ethyleniquc out rendu inefficace le procede de trans-csterification en presence de la resine Amberlyst 15 (H+).
TL;DR: In the presence of an alcohol, oxalic acid esters undergo diazomethane-catalyzed transesterification as discussed by the authors, in which they undergo transesterization under mild reaction conditions.
Abstract: In the presence of an alcohol, oxalic acid esters undergo diazomethane-catalyzed transesterification. Under mild reaction conditions, esters of homologous dicarboxylic acids and other polycarboxyli...