Patent ID: 7074951

Claim:
A process for the production of dimethyl carbonate comprising the steps of: (a) feeding a stream containing urea, methanol, water and ammonium carbamate to a first reaction/distillation zone: (b) concurrently in said first reaction/distillation zone, (i) reacting water with urea to form ammonium carbamate, (ii) decomposing the ammonium carbamate in the feed and the ammonium carbamate from the reaction of water with urea into ammonia and carbon dioxide, and (iii) separating the ammonia, carbon dioxide and methanol from the urea and by distillation; (c) removing ammonia, carbon dioxide and methanol from said first reaction/distillation zone as a first overheads; (d) removing urea and methanol from said first reaction/distillation zone as a first bottoms; (e) feeding said first bottoms and methanol to a second reaction/distillation zone; (f) concurrently in said second reaction/distillation zone, (i) reacting methanol and urea in the presence of a homogeneous catalyst comprising an organotin complex compound of dialkylmethoxide in a high boiling solvent to form dimethyl carbonate and (ii) separating dimethyl carbonate and ammonia from the homogeneous catalyst by distillation; (g) removing dimethyl carbonate and methanol from said second reaction/distillation zone as a second overheads; and (h) removing a second bottoms from said second reaction/distillation zone.