锌盐催化尿素和甲醇合成碳酸二甲酯

以尿素和甲醇为原料,各种锌盐为催化剂,在反应釜中合成了碳酸二甲酯（DMC）.实验结果表明,在相同的实验条件下,ZnCl2具有最佳的催化性能.进一步研究表明,该路线为两步反应,首先由尿素和甲醇反应生成中间物氨基甲酸甲酯（MC）,第二步MC继续和甲醇反应生成DMC,其中第二步反应为速控步骤.并且以该催化剂为模板催化剂,考察了反应条件如：反应温度、反应时间和催化剂用量对DMC收率的影响.结果表明,当反应温度为180℃,反应时间为8h,催化剂用量为1.0g时,DMC收率可以达到28.9％.

Synthesis of Dimethyl Carbonate from Urea and Methanol over Zinc Salts

In the batch reactor, several zinc salts were used as the catalysts for the synthesis of dimethyl carbonate （DMC） from urea and methanol. Under the same conditions, ZnC12 presented the best catalytic performance. In further study, it was re- vealed that this reaction could be divided into two steps. The intermediate methyl carbamate （MC） was first formed, and fur- ther converted to DMC by reaction of MC with methanol. And the second step was the key and rate - control step for this ap- proach. In addition, using ZnC12 as the model catalyst, the effects of reaction conditions on its catalytic performance were ex- plored in details. The catalytic evaluation results indicated that under optimal reaction conditions： reaction temperature 180 ℃, reaction time 8 h, catalyst amount 1.0 g, the DEC yield was about 28.9%.