PROCESS FOR PREPARING DIPHENYL ISOPHTHALATE AND DIPHENYL TEREPHTHALATE

摘要

Diphenyl isophthalate and diphenyl terephthalate are prepared by reacting isophthalic acid or terephthalic acid with diphenyl carbonate in the presence of stannous oxide (SnO) as the catalyst at a temperature of about 250 -300 C. for about 30 minutes to several hours depending on the temperature. During the heating period phenol is removed at atmospheric pressure after which a vacuum is applied, any excess diphenyl carbonate is removed, and the diphenyl isophthalate or diphenyl terephthalate recovered.