an improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed . the improvement entails the following steps introducing the resulting vapor stream at the mid - height of a first distillation column , and separating the vapor stream into a top product containing high purity monohydroxy aryl compound and a first bottom product , and recycling the high purity monohydroxy aryl compound of to the reaction , and introducing the first bottom product at mid - height of a second distillation column , and separating said first bottom product into high boiling bottom by - product and overhead remaining constituents , and introducing the overhead remaining constituents at mid - height of a third distillation column , and separating said overhead remaining constituents into overhead low - boiling fractions and bottom or product side stream that contains diaryl carbonate product , and recycling the diaryl carbonate product directly to the transesterification reaction .