Patent ID: 6855795

Claim:
A process for producing a polycarbonate having the structure: in which n is any number between about 5 and 50, R is any C 1 to C 20 alkyl group, whether straight-chain, cyclic, or branched, comprising the steps of: a) reacting a reaction mixture comprising an aliphatic diol according to the formula: HO—R—OH in which R is any C 1 to C 20 alkyl group, whether straight-chain, cyclic, or branched and a linear organic carbonate having the formula: in which R 1 and R 2 may independently be alkyl groups ranging from C 1 to C 4 , linear or branched, at a temperature of 60° C. to 180° C. in the presence of a catalyst selected from the group consisting of: one or more alkali or alkaline earth metal alkoxide, hydroxide, carbonate, or carboxylate salts, or mixtures of any of the foregoing; b) supplying heat to said reaction mixture to cause distillation of alcohol by-product(s) produced from step a) above until said reaction mixture reaches a termination temperature of at least 150° C. to provide a semi-stripped crude product; c) contacting said semi-stripped crude product from step b) with a chelating agent; to form a slurry; and d) filtering said slurry from step c) to provide a clear liquid.