Design and Control of Dimethyl Carbonate−Methanol Separation via Extractive Distillation in the Dimethyl Carbonate Reactive-Distillation Process

Abstract

Dimethyl carbonate is an environmentally benign and biodegradable chemical. It can be produced by a transesterification reaction of methanol with ethylene carbonate, coproducing another useful product, ethylene glycol. A reactive distillation column can be utilized for the complete conversion of ethylene carbonate with methanol in excess. The coproduct, ethylene glycol, is the bottom product while the top product of this reactive distillation column is a mixture of dimethyl carbonate and methanol close to the azeotropic composition. In this paper, an economical separation process via extractive distillation is proposed to obtain pure dimethyl carbonate product and also pure methanol to be recycled to the reactive distillation column. A very simple procedure is proposed in this paper for the quick comparison of alternative entrainer candidates before rigorous process simulation is conducted. Aniline is found to be a very effective entrainer to enhance the relative volatility between methanol and dimethyl c...