Patent ID: 9150490
Filing Date: 2015-10-06
Classification: C07C,C08G,C25B,Y02P

Abstract:
1. A process for preparing diaryl carbonate, comprising: (a) preparing phosgene by reaction of chlorine with carbon monoxide, (b) reacting the phosgene formed in step (a) with at least one monophenol in the presence of a catalyst to form at least one diaryl carbonate and hydrogen chloride, wherein the catalyst is selected from the group consisting of titanium chloride, zirconium chloride, aluminium chloride, and titanium phenoxide, (c) isolating and working-up of the diaryl carbonate formed in step (b), (d) isolating the hydrogen chloride formed in step (b), (e) preparing an aqueous solution of the hydrogen chloride, (f) electrochemically oxidizing at least part of the aqueous hydrogen chloride solution from (e) to chlorine with formation of water by using a gas diffusion electrode as an oxygen-depolarized cathode, and (g) recirculating at least part of the chlorine prepared in step (f) to the preparation of phosgene in step (a).