METHOD FOR PRODUCING DIARYL CARBONATES

摘要

The invention concerns a method for producing diaryl carbonates from monophenols and phosgene or chloroformic acid aryl esters in the presence of an optionally substituted pyridine or the hydrochloride salt thereof as catalyst, and the recovery and reinjection thereof back into the method. The method is carried out at least partially in a liquid phase without the use of an additional solvent, the catalyst being separated by means of crystallization and recovered.

主权项

1. A process for preparing diaryl carbonate comprising:
a) reacting a monophenol with phosgene and/or at least one aryl chloroformate in the presence of at least one optionally substituted pyridine, in free form and/or in the form of a hydrochloride salt thereof, as catalyst, wherein the reaction is carried out in a reactor under pressures of 1-50 bar, b) transferring the reaction mixture from the reactor into an apparatus configured for suspension crystallization, c) lowering the temperature in the apparatus, thereby introducing the suspension crystallization and forming a crystallizate, d) separating the crystallizate from the remaining catalyst-containing mother liquor, and e) at least partially recirculating the catalyst-containing mother liquor into the reactor at step a).