METHOD FOR PRODUCING DIPHENYL CARBONATE AND METHOD FOR PRODUCING AROMATIC POLYCARBONATE

摘要

PROBLEM TO BE SOLVED: To obtain a purified diphenyl carbonate usable as a raw material for a less-colored polycarbonate by reducing the total chlorine of an acidic polymerization inhibitory substance derived from chlorine to 20 ppb or below. SOLUTION: The method for producing diphenyl carbonate comprises a step for reacting phosgene with phenol to form a crude-diphenyl carbonate and a step for purification in which the crude-diphenyl carbonate containing water and impurities is continuously distilled. The continuous distillation of the purifying step includes a pre-distillation for removing the water and the impurities having lower boiling points than that of the diphenyl carbonate and a subsequent distillation for recovering the purified diphenyl carbonate. The pre-distillation is characterized in that a basic substance is fed and brought into countercurrent contact with the impurities having the lower boiling points. The diphenyl carbonate obtained by the above method is reacted with an aromatic dihydroxy compound.