Patent ID: 6437082
Filing Date: 2002-08-20
Classification: B01J,C08G,G01N

Abstract:
A method for making polycarbonate, comprising the steps of:(a) combining a stream of a dihydric phenol and a stream of diarylcarbonate to form a reaction mixture; (b) passing the reaction mixture through a series of reaction stages in which the dihydric phenol and the diarylcarbonate react to form polycarbonate; and (c) periodically monitoring the composition of the reaction mixture at one or more of the reaction stages to determine the overall stoichiometric ratio of dihydric phenol to diarylcarbonate; and (d) adjusting the stream of a dihydric phenol, the stream of diarylcarbonate or both to maintain the overall stoichiometric ratio within a predefined range, wherein the composition of the reaction mixture is monitored using infrared spectroscopy.