Showing papers on "Transesterification published in 1982"

Bisphenol‐A polycarbonate–poly(butylene terephthalate) transesterification. II. Structure analysis of the reaction products by IR and 1H and 13C NMR

Abstract: The structure of the four-component copolyester resulting from the exchange reaction between molten bisphenol-A polycarbonate and poly(butylene terephthalate) is analyzed as a function of the reaction time by infrared and nuclear magnetic resonance spectroscopy. By applying a statistical method developed earlier, the mean chain length of the various sequences as well as the degree of randomness is computed. The exchange reaction leads initially to the formation of a block copolyester with reduced solubility. As the reaction proceeds, a soluble random copolycondensate is progressively formed.

The Trans-esterification of Bisphenol-a Polycarbonate (pc) and Polybutylene Terephthalate (pbtp) - a New Route To Block Copolycondensates

Abstract: In this work, the exchange reaction taking place in molten blends of bisphenol-A polycarbonate and polybutylene terephthalate was studied. A direct transesterification mechanism catalyzed by titanium residues, present in commercial PBTP, was deduced. The transesterification reaction can be -stopped at various levels by additives capable of complexing the titanium catalyst. This work enhances the possibility of a new approach in macromolecular engineering by directly combining polycondensates in a processing machine such as an extruder.

Bisphenol-A polycarbonate-poly(butylene terephthalate) transesterification. III. Study of model reactions

Abstract: Exchange reactions in molten bisphenol-A polycarbonate–poly(butylene terephthalate) mixtures are investigated by means of model reactions. Transesterification can result either from direct ester-ester interchange or via alcoholysis or acidolysis. Among the various reactions investigated, only the PBTP alcoholysis by phenol is not found to occur. Taking into account that bisphenol-A terephthalate units (A2B1) and butylene carbonate units (A1B2) are formed in equimolecular amounts, it is concluded that direct ester-ester interchange is the most likely mechanism for PC-PBTP transesterification.

Bisphenol-A polycarbonate–poly(butylene terephthalate) transesterification. IV. Kinetics and mechanism of the exchange reaction

Abstract: The kinetic aspects of the bisphenol-A polycarbonate–polybutylene terephthalate exchange reaction are considered as a function of temperature and of the PC/PBTP ratio. The most likely mechanism is a direct reversible ester-ester interchange reaction catalyzed by titanium residues present in commercial PBTP.

Transesterification of vegetable oils for fuels

Abstract: A continuous procedure was developed and tested, in a stepwise manner, for the transesterification of soybean and sunflower oils using ethanol. Good yields of ethyl soyate and sunflowerate were achieved, and the products made agreed very closely with those made by a direct esterification of the acids of vegetable oils and ethanol. The viscosity of the esters was considerably less than that of the oils and more nearly like that of diesel fuel. Because the ethyl soyate and sunflowerate have many components which solidify at relatively high temperatures, cloud points of the fuels are about 8 to 12/sup 0/C, which indicates they would not be readily usable at or below that temperature without dilution with No. 1 or No. 2 diesel fuel and/or the addition of additives. 3 figures, 7 tables.

Vegetable oils: a new alternative

Abstract: This paper relates: (1) the use and production of methyl ester of vegetable oil, M.E.V.O., as fuel in diesel engines and the effect of the catalyst proportion, alcohol and vegetable oil V.O. on the transesterification process; (2) simple control methods during industrial preparation and the behavior of V.O. and M.E.V.O. on accelerated oxidation test to determine the maximum contration of V.O. in M.E.V.O. that do not cause problems on the injectors; and (3) the behavior of M.E.V.O. and V.O. on parafinic and naphtenic lubricants, with high T.B.N. and without organo-metallic compounds, using antioxidants as B.H.T. to reduce the oxidation effect. 9 figures, 7 tables.

Polymeric foams from transesterified by-product derived from manufacture of dimethyl terephthalate and laminates therefrom

Abstract: Cellular foams, particularly polyisocyanurate foams, are prepared by reacting together an organic polyisocyanate, a blowing agent, a trimerization catalyst, and a minor amount of a polyol mixture prepared by the transesterification with a glycol of a by-product fraction from the manufacture of dimethyl terephthalate, the major portion of said fraction comprising about 15 to 70 weight percent of dimethyl terephthalate, and about 85 to 30 weight percent of a mixture of monomethyl terephthalate, bi-ring esters and polymeric materials. Laminates of such foams exhibit a high degree of fire resistance, low smoke evolution on combustion, low foam friability and high compressive strength.

Extractive distillation of alcohol-ester mixtures and transesterification

Abstract: A C 1 -C 4 alkanol and its corresponding acetate or a C 1 -C 2 alkanol and its corresponding propionate are separated by extractive distillation utilizing an aromatic hydrocarbon as the extractive solvent Transesterification of lower alkanols and lower alkyl acetates or propionates is effected by means of extractive distillation and the preparation of an intermediate ester of a higher boiling alcohol

Process for coating and curing thermosetting resinous binder compositions using transesterification catalyst

Abstract: A thermosetting binder composition for coating, comprising: (I) (1) A non-acidic resinous saturated compound having a molecular weight of at least 900, and an alcoholic hydroxyl content of at least 0.2 eq./100 g; (2) A non-acidic polyester of a polycarboxylic acid crosslinking agent having more than one β-hydroxyl ester group per molecule, and at least one of components (1) and (2) having an alcoholic hydroxyl functionality of more than 2, and (II) A transesterification-promoting metal salt or complex curing catalyst which is soluble in liquid hydrocarbons. For aqueous compositions, component (I) (1) is preferably a neutralized epoxy resin/amine adduct and component (II) should be insoluble in water; they can be used for cathodic electrodeposition.

Organic reactions in emulsions—Preparation of glycerol and polyglycerol esters of fatty acids by transesterification reaction

Abstract: Monoglycerol and polyglycerol esters of fatty acids have been prepared in an emulsion medium of polyglycerol in esters of fatty acids. Transesterification between glycerol or polyglycerols and methyl esters of fatty acids is made at relatively low temperatures (95–150 C) in the presence of alkaline catalyst and anionic or nonionic emulsifiers. The reaction system consists of two immiscible phases transformed into a “milky” (macro) or transparent (micro) emulsion throughout the heating process. The product obtained using this technology is not a highly substituted ester since the transesterification reaction is selective. The type and the amount of emulsifier have to be carefully selected. Unsuitable emulsifiers which will not stabilize the emulsion are ineffective in enlarging the contact between the reactants; therefore, the conversion of the reactants is very poor. With suitable emulsifiers, the conversions and the yields improved due to a better contact between reactants.

Modeling of poly(ethylene terephthalate) reactors. II. A continuous transesterification process

Abstract: A comprehensive mathematical model for a continuous transesterification process has been built so as to enable prediction of the influence of different process and operational variables on productivity and by-product formation. The influence of temperatures and temperature profiles, of residence time and residence time distribution, and also of the number of reactors in series has been investigated. The modeling has been done as close to the industrial practice as possible. Important pragmatic implications from the point of view of operation of continuous transesterification are highlighted.

Extractive distillation of alcohol-ester mixtures

Abstract: A C 1 -C 4 alkanol and its corresponding acetate or a C 1 -C 2 alkanol and its corresponding propionate are separated by extractive distillation utilizing an aromatic hydrocarbon as the extractive solvent. Transesterification of lower alkanols and lower alkyl acetates or propionates is effected by means of extractive distillation and the preparation of an intermediate ester of a higher boiling alcohol.

Preparation of predominately methyl acrylamidoglycolate methyl ether in a normally liquid product

Abstract: Reaction of glyoxylic acid with a C 3 to C 6 alcohol capable of forming an azeotrope with water to form the C 3 to C 6 alkyl glyoxylate or alkyl glyoxylate alkyl hemiacetal, reacting the intermediate with acrylamide and optionally with a C 3 to C 6 alcohol to form the C 3 to C 6 alkyl acrylamidoglycolate or alkyl acrylamidoglycolate alkyl ether in essentially polymer free form which are readily converted by transesterification/etherification or transesterification/transetherification with methanol into predominately methyl acrylamidoglycolate methyl ether preferably in liquid form.

Polyester blend compositions exhibiting suppression of transesterification

Abstract: The present invention provides a non-burning, non-dripping polyester blend composition in which transesterification is suppressed, as indicated by, eg, improved heat deflection temperature The composition comprises (a) approximately 35 to 85 percent by weight of a blend of polyethylene terephthalate and polybutylene terephthalate wherein the polyethylene terephthalate comprises approximately 10 to 25 percent by weight of the blend; (b) approximately 5 to 60 percent by weight of a reinforcing agent; (c) approximately 4 to 15 percent by weight of at least one halogen-containing organic flame retardant compound; and (d) approximately 2 to 10 percent by weight of the amorphous non-abrasive reaction product of antimony trioxide, or a compound of antimony which generates antimony trioxide, and a substrate comprising a hydrous compound of silicon in a weight ratio within the range of approximately 1:1 to 1:4, on an antimony trioxide: substrate basis The composition may further comprise approximately 01 to 8 percent by weight of a thermoplastic phenoxy resin and/or approximately 05 to 25 percent by weight of a polytetrafluoroethylene resin The amorphous non-abrasive reaction product is preferably the reaction product of antimony trioxide and talc, preferably in a 25:75 or 45:55 weight ratio A process for suppressing transesterification in glass reinforced, non-burning, non-dripping polyester blend compositions is also disclosed

Method of making polyester prepolymers

Abstract: A polyester prepolymer having increased reactivity when subjected to molecular weight buildup, such as in solid phase polymerization is prepared by an improved method which includes the steps of: reacting a dicarboxylic acid and a glycol in the presence of a transesterification catalyst to form a reaction mixture containing condensation oligomers; purifying the reaction mixture to remove substantially all of the reaction by-products and residual dicarboxylic acid, glycol and catalyst and to crystallize the condensation oligomers; and polycondensing the oligomers to form a molten prepolymer.

Process for the preparation of aromatic glycidyl esters

Abstract: Aromatic mono or polycarboxylic acid glycidyl esters are obtained in good yields and high purity by transesterification of the corresponding aromatic carboxylic acid alkyl esters with glycidol in the presence of weakly toxic catalysts, namely the alkali, ammonium, and alkaline earth metal salts of pseudohalogen hydride acids with readily polarizable anions.

ID catalyzed reactions and compositions for use therein

Abstract: Certain urea-sulfuric acid components, comprised of urea and sulfuric acid in a 1/4 to 7/4 molar ratio, contain a monourea adduct of sulfuric acid, which is catalytically active for promoting organic chemical reactions. The invention provides methods employing such urea-sulfuric acid components for catalyzing organic reactions such as oxidation, oxidative addition, reduction, reductive addition, esterification, transesterification, hydrogenation, isomerization (including racemization of optical isomers), alkylation, polymerization, demetallization of organometallics, nitration, Friedel-Crafts reactions, and hydrolysis. Novel catalysts are disclosed which involve combinations of the urea-sulfuric component with one or more transition metal halides and/or with one or more surfactants. The surfactant-containing compositions are particularly useful for the treatment of materials containing lipophilic substances. Novel compositions containing the urea-sulfuric acid component and one or more organic reactants are also disclosed.

Polymeric foams from transesterified by-product derived from manufacture of dimethyl terephthalate

Abstract: Cellular foams, particularly polyisocyanurate foams, are prepared by reacting together an organic polyisocyanate, a blowing agent, a trimerization catalyst, and a minor amount of a polyol mixture prepared by the transesterification with a glycol of a by-product fraction from the manufacture of dimethyl terephthalate, the major portion of said fraction comprising about 15 to 70 weight percent of dimethyl terephthalate, and about 85 to 30 weight percent of a mixture of monomethyl terephthalate, bi-ring esters and polymeric materials. Laminates of such foams exhibit a high degree of fire resistance, low smoke evolution on combustion, low foam friability and high compressive strength.

Process for the preparation of 2-isosorbide nitrate

Abstract: The invention relates to a process for the preparation of isosorbide-2-nitrate of the formula: by acylation of isosorbide with 1 to 2 molar equivalents of a carboxylic acid anhydride and 0.005 to 0.02 molar equivalents of a metal salt of metals of the 2nd, 3rd, 4th , 5th or 8th group of the periodic table as a catalyst with formation of isosorbide-5-acylate with high selectivity of at least 90%, nitration of this isosorbide-5-acylate to isosorbide-5-acylate-2-nitrate and subsequent conversion of this isosorbide 5-acylate-2-nitrates to isosorbide-2-nitrate by partial transesterification with a lower alcohol in the presence of an alkali metal alcoholate.

Process for removing glycerine

Abstract: The distillative separation of a mixture of glycerine and glycerine-based acetal or ketal transesterification products is aided by addition of a borate ester-forming compound to the mixture prior to distillation.

A new two-step method for synthesis of polycarbonates.

Abstract: Carbonate monomers, such as 1,4-bis(cyclohexyloxycarbonyloxylmethyl)-benzene and related compounds were synthesized from potassium cyclohexanolate, CO2, and α,ω-dibromo compounds in the presence of 18-crown-6 ether in aprotic solvents. Poly(p-xylylidene) was found to be formed in addition to the carbonate monomer when all the substances were simultaneously introduced into the reaction mixture. By an appropriate reaction method and conditions the formation of by-products was eliminated, thus permitting the main product 1,4-bis(cyclohexyloxycarbonyloxymethyl)benzene to be obtained in a yield higher than 90% with respect to the p-xylylene α,ω-dibromide introduced. The carbonate monomer thus obtained was then used in transesterification with diols or diphenols, and also in an ester exchange reaction to form the corresponding polycarbonates. The polycarbonates obtained were characterized and their reduced viscosity was determined.

Production of easily slidable polyester

Abstract: PURPOSE: To obtain an easily slidable polyester excellent in transparency and easy slidability, by reacting terephthalic acid with a glycol, adding a P compound, depolymerizing the mixture and, after adding a Li compound and a Ca compound, polycondensing the reaction mixture. CONSTITUTION: In producing a polyester by the transesterification (or esterification) and polycondensation from starting materials comprising terephthalic acid or a bifunctional carboxylic acid mixture based thereon, or its esterifiable derivative and ethylene glycol, a gltcol mixture based thereon, or its esterifiable derivative; the transesterification or esterification is performed first, then the prepolymerization is carried out, and then a phosphorus compound is added. An oligomer contained in the formed polyester is depolymerized with a glycol at a temperature higher than the m.p. of the polyester in an inert gas atmosphere. To this are further added both a lithium compound and a calcium compound, and the polycondensation is started and continued to completion. COPYRIGHT: (C)1984,JPO&Japio

Nucleating agents for polycarbonate resins prepared via transesterification of bisphenol-A and diphenyl carbonate

Abstract: A process for the manufacture of a crystallized polycarbonate resin prepared via the transesterification of a diaryl carbonate and a dihydric phenol comprising adding to the polycarbonate resin a minor amount of a lithium compound nucleating agent.

A process for the preparation of thermoplastic polyphosphonatophenyl ester carbonates

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.

Production of carboxyl group-containing polyester resin

Abstract: PURPOSE:To obtain titled resin suitable as a material for powder coatings, by reacting an OH group-containing polyester resin with an intermediate having both an epoxy group and an ester group prepared by the reaction between a polyepoxy compound and a monoalkyl terephthalate. CONSTITUTION:A polyepoxy compound having at least two epoxy groups, e.g., bisphenol A-derived epoxy resin, is reacted with a monoalkyl terephthalate, e.g., monomethyl terephthalate, to obtain an intermediate having both an epoxy group and an alkyl ester group. This intermediate is reacted with an OH group-containing polyester resin at a weight ratio of 28/80-80/20 in the presence of a transesterification catalyst to obtain an epoxy group-containing polyester resin. USE:This resin is combined with a curing agent such as sebacic acid, dodecanedioic acid, a carboxyl group-containing polyester resin or a carboxyl group-containing acryl resin, to obtain a powder coating which can be cured without evolution of volatile matter.