Patent ID: 8044226

Claim:
A high-purity diphenyl carbonate, wherein the diphenyl carbonate is unsubstituted or substituted with a lower hydrocarbon, and has a halogen content of not more than 1 ppb, 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 T containing the diaryl carbonate and a column bottom component A B containing the catalyst and a high boiling point material, (b) said column top component A T is continuously introduced into a diaryl carbonate purifying column B having a side cut outlet, and continuously subjected to separation by distillation into a column top component B T , a side cut component B S and a column bottom component B B , the high-purity diaryl carbonate being continuously withdrawn as the side cut component B S , and (c) said column top component B T is continuously introduced into an intermediate boiling point material separating column C having a side cut outlet, and continuously subjected to separation by distillation into a column top component C T having said alkyl aryl carbonate as a main component thereof, a side cut component C S having as a main component thereof said intermediate boiling point material having a boiling point between that of said alkyl aryl carbonate and that of said diaryl carbonate, and a column bottom component C B having said diaryl carbonate as a main component thereof.