Patent ID: 8173762
Filing Date: 2012-05-08
Classification: C07C,C08G

Abstract:
1. A process for preparing oligocarbonate and/or polycarbonate comprising: a) transesterifying a bisphenol with a diaryl carbonate to obtain an oligocarbonate and/or polycarbonate and a monophenol; b) isolating or separating said oligocarbonate and/or polycarbonate from said monophenol; c) reacting said monophenol in the presence of an alkali solution with a carbonyl dihalide and separating the resulting products, wherein said products comprise an alkali metal halide and a diaryl carbonate, wherein said diaryl carbonate is reused in step a); d) electrochemically oxidating said alkali metal halide obtained in step c) to obtain a halogen and an alkali hydroxide solution; e) reacting at least a portion of said halogen from step d) with carbon monoxide to obtain a carbonyl dihalide, wherein at least a portion of said carbonyl dihalide is used in step c); f) reusing at least a portion of said alkali hydroxide solution obtained from step d) in step c).