Preparation of polycarbonate having a predetermined molecular weight and level of endcapping

摘要

A melt method of preparing polycarbonate having a predetermined number average molecular weight and percent endcapping is described. A computerized process model is used to determine the reaction parameters to be employed in order to furnish the product polycarbonate possessing the desired Mn and %EC. Reaction parameters of importance include a suitable starting molar ratio of diaryl carbonate to dihydroxy aromatic compound, the most appropriate reaction time, reaction temperature and pressure ranges. The target polycarbonate is then prepared using reaction parameters indicated by the process model in a reactor which forms an element of the process model. Characteristics of the reactor which may be included in the process model include agitation rate and reflux ratio during the distillative removal of hydroxy aromatic compound formed as a by-product during the polymerization.