Process for production of high-purity diaryl carbonate

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 AT containing the diaryl carbonate and a column bottom component AB containing the catalyst and a high boiling point material,
• (b) said column top component AT 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 BT, a side cut component BS and a column bottom component BB, the high-purity diaryl carbonate being continuously withdrawn as the side cut component BS, and
• (c) said column top component BT 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 CT having said alkyl aryl carbonate as a main component thereof, a side cut component CS 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 CB having said diaryl carbonate as a main component thereof.