Patent ID: 8044167
Filing Date: 2011-10-25
Classification: B01D,C07C,C08G,Y02P

Abstract:
1. An aromatic polycarbonate that is obtained by transesterification between a high-purity diphenyl carbonate and an aromatic dihydroxy compound; wherein the high-purity diphenyl carbonate is unsubstituted or substituted with a lower hydrocarbon, and has a halogen content of not more than 0.1 ppm, a content of an intermediate boiling point material of not more than 100 ppm, and a content of by-products having a higher boiling point than that of said diphenyl carbonate of not more than 100 ppm; and wherein the high-purity diphenyl carbonate is prepared by a process that comprises taking as a starting material a reaction mixture containing an alkyl aryl carbonate that has been obtained through a transesterification reaction between a dialkyl carbonate and an aromatic monohydroxy compound, continuously feeding the starting material into a reactive distillation column comprising a continuous multi-stage distillation column in which a homogeneous catalyst is present, carrying out a transesterification reaction and distillation simultaneously in said column, continuously withdrawing a low boiling point reaction mixture containing a produced dialkyl carbonate from an upper portion of the column in a gaseous form, and continuously withdrawing a high boiling point reaction mixture containing a diaryl carbonate from a lower portion of the column in a liquid form, wherein: (a) said high boiling point reaction mixture is continuously introduced into a high boiling point material separating column A, and continuously subjected to separation by distillation into a column top component A (b) said column top component A (c) said column top component B