High-Yield Synthesis of Dimethyl Carbonate from Urea and Methanol Using a Catalytic Distillation Process

Reaction equilibrium for the dimethyl carbonate (DMC) synthesis from urea and methanol was calculated based on the Benson method, and results showed that the reaction was thermodynamically unfavorable. In addition, urea methanolysis was conformed to be a consecutive reaction. Major side reactions in the DMC synthesis included the thermal decomposition of DMC and reaction between methyl carbamate (MC) and DMC, which reduced the DMC yield in the batch process. A catalytic distillation technique was proposed in this study to minimize the side reactions and unfavorable equilibrium for DMC synthesis. The DMC yield reached 60−70% in the catalytic distillation reactor over a Zn-based catalyst.