GB808488A - Process for the production of high molecular weight polycarbonates - Google Patents

Abstract

In the manufacture of fibre- or film-forming polycarbonates (a) by interesterifying a dialkyl-, dicycloalkyl- or diaryl-carbonate or a dialkyl-, dicycloalkyl- or diaryl-dicarbonate of an aromatic dihydroxy compound with an alkyl-, cycloalkyl- or aryl-dihydroxy compound; or (b) by polycondensing a dialkyl-, dicycloalkyl-or diaryl-dicarbonate of an aromatic dihydroxy compound alone, reaction is effected in the presence of a basic catalyst which is neutralized in the course of or at the end of the interesterification or polycondensation by adding a base-binding material to the melt. A large number of reactants are referred to. The basic catalyst may be an alkali or alkaline earth metal or an alcoholate, phenolate (e.g. of phenol or a dimono-hydroxyaryl alkane), hydride, oxide, amide or a basic reacting salt thereof (e.g. acetate, benzoate or carbonate). The base-binding material may be an aromatic sulphonic acid, an organic acid halide, an organic chloroformate, a dialkyl sulphate, an organic chlorine compound or an acid salt of a polybasic inorganic acid. Preferably volatile base-binding materials are used and excess thereof is removed from the polycarbonate under reduced pressure. Examples describe the production of polycarbonates from (1) hexane diol and diethyl carbonate; (2) 2,2-di-(p-hydroxyphenyl) propane and diphenyl carbonate; (3) bisphenyl dicarbonate of 2,2-(p-hydroxyphenyl) propane and 2,2-di-(p-hydroxyphenyl) propane; (4) 2,2-di - (p - hydroxyphenyl) butane and diphenyl carbonate; (5) 2,2-di-(p-hydroxyphenyl) propane and di-o-cresylcarbonate; (6) bis-phenyl-carbonate of 2,2-di-(p-hydroxyphenyl) propane; (7) bis-phenylcarbonate of 2,2-di-(p-hydroxyphenyl propane and the bis ethylcarbonate of 2,2 di-(p-hydroxyphenyl) propane; (8) bis-phenylcarbonate of 2,2-di-(p-hydroxyphenyl) propane and 2,2-di-(p-hydroxyphenyl) propane; (9) bis-phenyl carbonate of resorcinol. Specifications 650,002, 772,627, 808,485, 808,486, 808,487 and 808,489 are referred to.