METHOD FOR MAKING POLYCARBONATE

摘要

A method of making polycarbonate comprises melt-polymerizing an aromatic dihydroxy compound and a carbonic acid diester in a presence of a polymerization catalyst in a reactor system producing a byproduct stream, wherein the polymerization catalyst comprises a quaternary phosphonium compound; and purifying the byproduct stream to separate the carbonic acid diester, wherein the separated carbonic acid diester has a phosphorous concentration of less than or equal to about 30 parts per million.