MELT POLYCARBONATE CATALYST SYSTEMS

摘要

This invention provides a method for preparing polycarbonates, which utilizes polycondensation catalysts which are salts of certain phenanthroline compounds. We have found that this new class of catalysts provide excellent polymerization rates for the preparation of Bisphenol A polycarbonate from the melt polymerization of diphenyl carbonate and Bisphenol A. Moreover, the catalysts of the invention were found to be very selective in substantially reducing the level of branching side reaction, i.e., formation of Fries product, normally associated with the melt polycarbonate process.