Patent ID: 6437166
Filing Date: 2002-08-20
Classification: C07C

Abstract:
A process comprising the steps of:(a) preparing a diaryl carbonate by means of a direct carbonylation reaction, said direct carbonylation reaction resulting in the formation of a first mixture comprising said diaryl carbonate, an aromatic hydroxy compound, water, base and quaternary salt; (b) removing at least 0.2 wt. %, based on the weight of said first mixture, of a distillate comprising said aromatic hydroxy compound, from the liquid phase of said first mixture, at pressures from 10 to 200 mbar and at temperatures of from 40 to 160Â° C., the removal to said distillate resulting in the formation of a second mixture; (c) crystallizing an adduct of said diaryl carbonate and said aromatic hydroxy compound from said second mixture; (d) separating said crystallized adduct from said second mixture, the separation of said crystallized adduct resulting in the formation of a third mixture; and (e) recycling said third mixture, without further work up, to said direct carbonylation reaction of step (a).