Showing papers on "Transesterification published in 1971"
TL;DR: In this article, the influence of different types of catalysts on polycondensation reaction has been studied in a model system and it has been found that two kinds of catalyst are to be distinguished.
Abstract: The influence of different types of catalysts on the polycondensation reaction has been studied in a model system. It has been found that two kinds of catalysts are to be distinguished. “Transesterification” catalysts (Mn, Pb, Zn) are very active in media having both a high and a low hydroxyl content. However, they are easily poisoned by very small amounts of carboxylic endgroups. This restricts their activity to the period of transesterification. The “polycondensation” catalyst antimony is insensitive to the presence of acidic endgroups. However, its activity is inversely proportional to the hydroxyl group concentration For this reason antimony is hardly effective during transesterification. During polycondensation it becomes gradually more active.
41 citations
28 citations
26 citations
Patent•
14 Jan 1971
TL;DR: In this paper, the transesterification of a mixture of 50 to 90 mole-% terephthalic acid dialklesters with 2 or 3C-atoms is described.
Abstract: Mixtures of 50 to 90 mole-% terephthalic acid dialklesters and 10 to 50 mole-% 4,4'-diphenyldicarboxylic acid dialkylesters whose alkyl grps. may contain up to 4C-atoms, are transesterified, in presence of a catalyst, with 2 to 2.4 times the molar amount of a mixture comprising 50 to 90 mole-% of an aliphatic diol with 2 or 3C-atoms and 10 to 50 mole-% 1,4-dimethylolcyclohexane, at 160- to 210 degrees C, and the transesterification product is then polycondensed at 260 to 350 degrees C in known manner. The mixture pref. comprises 60 mole-% dimethyl terephthalate and 40 mole-% 4,4'-diphenyldicarboxylic acid dimethyl ester with 70 mole-% ethylene glycol and 30 mole-% 1,4-dimethylolcyclohexane. The products hav e freezing temps. between 100 and 130 degrees C, and are suitable for manufacture of amorphous mouldings which are resistant to relatively high temperatures.
13 citations
Patent•
21 May 1971
TL;DR: In this article, the authors describe a second ALKYL group in the 2 or 3 position of the PHENYL RING, which is used to support the construction of organics.
Abstract: ESTERS OF DIPENTAERYTHRITOL OR TRIPENTAERTHRITOL AND 4HYDROXY-5ALKYLPHENYLALKANOIC ACIDS HAVING A SECOND ALKYL GROUP IN THE 2 OR 3 POSITION OF THE PHENYL RING ARE STABILIZERS OF ORGANIC MATERIAL. THE COMPOUND ARE OBTAINED THROUFG TRANSESTERIFICATION TECHNIQUES.
11 citations
Patent•
10 Aug 1971
Abstract: Improvements in the production of polyesters of dicarboxylic acid moieties and 1,4-butanediol moieties, where at least some of the acid moieties are aromatic, by catalytic direct or transesterification of the acids or esters thereof with a molar excess of 1,4- butanediol, whereby reducing the amount of excess 1,4-butanediol required to produce commercially acceptible polyesters, which comprises reacting the 1,4-butanediol with the dicarboxylic acid or an ester thereof in a mole ratio of 1.05 to 1.25:1 respectively at temperatures of less than 200*C while distilling off the volatile cleavage products including the 1,4butanediol until the flow of butanediol has been reduced to less than about 10 percent of its initial removal rate, and then polycondensing this product at temperatures above 200*C in the usual manner.
10 citations
Patent•
30 Apr 1971TL;DR: In this article, a typical embodiment is diphenyl-imidazolyl-acetic acid 1-dimethylamino-2-propyl ester, which is prepared by treatment of the corresponding phenyl-halo-alkanoate or alkanamide with an azolyl compound or saalt thereof.
Abstract: Antimicrobial aminoalkyl phenyl-azolylalkanoates and N-(aminoalkyl)phenyl-azolylalkanamides and salts thereof are prepared by treatment of the corresponding phenyl-halo-alkanoate or alkanamide with an azolyl compound or saalt thereof, treatment of the corresponding phenyl-hydroxyalkanoate or phenyl-hydroxyalkanamide with an azole compound under dehydration conditions or with a thionyl-bis-azole, or transesterification or amidation of a (lower)alkyl phenyl-azolylalkanoate. A typical embodiment is diphenyl-imidazolyl-acetic acid 1-dimethylamino-2-propyl ester.
8 citations
Patent•
Esso1
TL;DR: Copolymers of vinyl ester and an ester of a dialkyl unsaturated dicarboxylic acid prepared by partial transesterification of a short chain alcohol ester with a C20 to C30 alcohol are flow improvers in residual and crude oils as discussed by the authors.
Abstract: Copolymers of vinyl ester and an ester of a dialkyl unsaturated dicarboxylic acid prepared by partial transesterification of a short chain alcohol ester of said dicarboxylic acid with a C20 to C30 alcohol are flow improvers in residual and crude oils.
7 citations
Patent•
24 May 1971TL;DR: In this paper, the authors describe the process of pre-preparing a C4 to C12 ALKYLENE GLYCOL and a lower DIALKYL TEREPHTHALATE in the presence of a TRANSESTERIFICATION CATALyst.
Abstract: THE PROCESS OF PREPARING A POLY(C4 TO C12 ALKYLENETEREPHTHALATE) RESIN COMPRISING CARRYING OUT A TRANSESTERIFICATION REACTION BETWEEN A C4 TO C12 ALKYLENE GLYCOL AND A LOWER DIALKYL TEREPHTHALATE IN THE PRESENCE OF A TRANSESTERIFICATION CATALYST REPRESENTED BY THE FORMULA MXTIF6,WHEREIN M IS A NH4-RADICAL, AN ALKALI METAL OR ALKALINE EARTH METAL, TO FORM A PREPOLYMER AND THEN POLYCONDENSING SAID PREPOLYMER.
6 citations
3 citations
TL;DR: Alkylation of methyl O-(tetrahydropyran-2-yl)-mandelate in dimethyl sulphoxide was shown to produce transesterification products at 80° whereas normal C-alkylation was observed at 25°.
Abstract: Alkylation of methyl O-(tetrahydropyran-2-yl)-mandelate in dimethyl sulphoxide was shown to produce transesterification products at 80° whereas normal C-alkylation was observed at 25°.
Patent•
06 Aug 1971TL;DR: In this article, the authors described the synthesis of 2-HYDROXYETHYL ESTERS with ETHYLENE GLYCOL in the presence of OXYGEN and a CATALYTIC AMOUNT of calcium hydrOXide of barium hydroxide at a temperature of 30-50*C.
Abstract: SYNTHESIS OF 2-HYDROXYETHYL ESTERS OF 2-QUINOXALINECARBOXYLIC ACID-1,4-DIOXIDES THROUGH THE TRANSESTERIFICATION OF THE LOWER ALKYL ESTERS WITH ETHYLENE GLYCOL IN THE PRESENCE OF OXYGEN AND A CATALYTIC AMOUNT OF CALCIUM HYDROXIDE OF BARIUM HYDROXIDE AT A TEMPERATURE OF 30-50*C
TL;DR: A detailed account of modern views on the structural analysis of triglycerides of natural fats by transesterification, lipase hydrolysis, determination of stereoisomerism, and establishment of polymorphism in their crystals is given in this paper.
Abstract: An account is given of modern views on the structural analysis of triglycerides of natural fats by transesterification, lipase hydrolysis, determination of stereoisomerism, and establishment of polymorphism in their crystals. The possibilities of the practical application of these methods in fat analysis are shown. A list of 172 references is included.
TL;DR: The corresponding higher esters were produced in good yields by transesterification of lower esters of adipic acid by alcoholysis with alcohols in the presence of an alkaline or acid catalyst as mentioned in this paper.
Abstract: The corresponding higher esters were produced in good yields by transesterification of lower esters of adipic acid by alcoholysis with alcohols in the presence of an alkaline or acid catalyst. Acid catalysts (p-toluenesulfonyl chloride) are more effective than alkaline catalysts (KOH).
Journal Article•
TL;DR: Spirocyclic glycolic esters of orthosilicic acid have been obtained by catalytic disproportionation of the corresponding polyesters formed during transesterification of tetraethoxysilane by glycols as discussed by the authors.
Abstract: Spirocyclic glycolic esters of orthosilicic acid have been obtained by catalytic disproportionation of the corresponding polyesters formed during transesterification of tetraethoxysilane by glycols. The PMR spectra of these compounds were studied and their dipole moments were measured.