Patent ID: 8569534

Claim:
A process for producing diaryl carbonate, comprising: a. reacting ammonia and carbon dioxide in a first reaction zone to form first reaction product comprising a urea; b. transesterifying the urea with ethanol in the presence of a first transesterification catalyst in a second reaction zone to form a second reaction product comprising diethyl carbonate and ammonia; c. separating the second reaction product to recover a first diethyl carbonate fraction and a first ammonia fraction; d. transesterifying at least a portion of the first diethyl carbonate fraction with an aryl hydroxy compound in the presence of a second transesterification catalyst in a third reaction zone to form a third reaction product comprising ethyl aryl carbonate and ethanol; e. separating the third reaction product to recover an ethyl aryl carbonate fraction and an ethanol fraction; f. disproportionating at least a portion of the ethyl aryl carbonate fraction in the presence of a disproportionation catalyst in a fourth reaction zone to form a fourth reaction product comprising diaryl carbonate and diethyl carbonate; g. separating the fourth reaction product to recover a diaryl carbonate fraction and a second diethyl carbonate fraction; h. recycling at least a portion of the ethanol fraction to the second reaction zone; and i. recycling at least a portion of the second diethyl carbonate fraction to the third reaction zone.