SE315024B - - Google Patents

Abstract

In the manufacture of polycarbonates by heating together a dihydric phenol and a bis-haloformate of a dihydric phenol with evolution of hydrogen halide, the reaction is effected in the presence of a solvent which is benzophenone, m-terphenyl, a chlorinated or brominated biphenyl, a chlorinated or brominated diphenyl oxide or a chlorinated or brominated naphthalene. Heating is effected at a temperature from 270 DEG C. to the reflux temperature, possibly in the presence of a tertiary amine as catalyst. The reaction mixture may also include a di-acid halide of an aromatic dicarboxylic acid or a chain-stopper which is a monohydric phenol or an acid halide of a monocarboxylic acid. The dihydric phenols are preferably dihydroxy benzenes, dihydroxy diphenyls, dihydroxy naphthalenes or their halogenated derivatives. They may also be bisphenols in which the radical joining the two hydroxyaryl groups may be one or more radicals selected from alkylene, alkylidene, tertiary amino, ether, carbonyl, sulphide, sulphoxide, sulphore and siloxy radicals and in which the hydroxyaryl groups may be substituted by halo, nitro-, hydrocarbyl or hydrocarbonoxy radicals. The aromatic dicarboxylic acid may be phthalic, isophthalic, terephthalic or a naphthalene dicarboxylic acid or halogen substituted derivatives thereof. At the end of the polymer-forming reaction, the polymer may be precipitated from the solvent by the addition of a non-solvent or, alternatively, the solvent may be removed by spray-drying or evaporation. In examples, polymers are made by reacting: (1) hydroquinone and resorcinol bischloroformate; (2) hydroquinone, hydroquinone bischloroformate and resorcinol bischloroformate; (3) chlorohydroquinone and hydroquinone bischloroformate; (4) hydroquinone and chlorohydroquinone bischloroformate; (5) bisphenol A and bisphenol A bischloroformate; (6) hydroquinone and bisphenol A bischloroformate; (7) hydroquinone, hydroquinone bischloroformate and isophthaloyl chloride by a one- or two-stage process; (8) hydroquinone, hydroquinone bischloroformate and 5 - chloroisophthaloyl chloride; (9) hydroquinone, resorcinol bischloroformate and isophthaloyl chloride; or hydroquinone, resorcinol, hydroquinone bischloroformate and isophthaloyl chloride by a one- or two-stage process; or hydroquinone, hydroquinone bischloroformate, resorcinol bischloroformate and isophthaloyl chloride; or hydroquinone, resorcinol, resorcinol bischloroformate, isophthaloyl chloride and terephthaloyl chloride by a one- or two-stage process. Reference is also made to reacting catechol with the bischloroformate of hydroquinone or resorcinol. Uses.-Films, fibres, electrical insulation or dielectrics, adhesives. Specification 984,524 is referred to.