| 摘要 |
Linear polycarbonates, suitable for the manufacture of shaped bodies, filaments, foils and films, are made by reacting diesters of dihydric alcohols and benzene hydroxycarboxylic acids with ester-forming derivatives of carbonic acid. Specified diesters are those obtained by reaction of 2 mols. of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycols, thiodiglycol, 1.2- or 1.3-propanediol, 1.3- or 1.4-butanediol, 1.5-pentanediol, 1.6-hexanediol, 2-ethylpropanediol-1.3, quinitol or p-xylylene diol with 1 mol. of vanillic acid, p-hydroxybenzoic acid, 4-hydroxy-3-chloro benzoic acid, 4-hydroxy-3-methyl benzoic acid or 4-hydroxy-3.5-dimethoxy benzoic acid. Reaction may be effected (a) by passing phosgene into an alkali metal salt of the diester, if desired in the presence of an inert solvent (b) by passing phosgene into a solution of the diester in an organic base (e.g. pyridine) or in a organic solvent (e.g. chloroform) containing an organic base or (c) by reacting the bis-chlorocarbonate of the diester either with the diester in the presence of an acid-binding agent (e.g. pyridine) or with an alkali metal salt of the diester. In examples polycarbonates are made by reacting (1) ethylene glycol divanillate and phosgene, the product being soluble in cresol, phenol, chlorophenol and chloroform; (2) ethylene glycol-bis-(4.4-dihydroxy) benzoate and phosgene.
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