离子液体催化碳酸二甲酯和乙醇酯交换合成碳酸甲乙酯

Ionic liquids as efficient catalysts for the synthesis of ethyl methyl carbonate viatransesterification of dimethyl carbonate and ethanol

考察了碱性离子液体催化碳酸二甲酯和乙醇酯交换反应合成碳酸甲乙酯的过程,筛选出催化性能较好的离子液体1-丁基-3-甲基咪唑溴盐([Bmim]Br)作为催化剂,并对酯交换反应条件进行优化。结果表明,[Bmim]Br对反应表现出优异的催化性能,在常压、反应温度90℃、反应时间12 h、n(碳酸二甲酯)∶n(乙醇)=1∶1和[Bmim]Br用量为碳酸二甲酯质量的2%条件下,碳酸二甲酯转化率为71.1%,碳酸甲乙酯选择性为81.8%。经回收和循环利用3次,催化剂仍保持较好的催化活性。

The synthesis of ethyl methyl carbonate （EMC） through transesterification of dimethyl carbonate （DMC） and ethanol over several kinds of alkaline ionic liquids as the catalysts was studied, The esuhs indicated that 1-butyl-3-methylimidazolium bromate （ [ Bmim ] Br） exhibited better catalytic performance in transesterification among the investigated alkaline ionic liquids. Furthermore, the reaction conditions were also optimized by using [ Bmim ] Br as the catalysts. The results showed that DMC conversion of 71.1% and the selectivity to EMC of 81.8% were attained under the optimum reaction condition as follows ： atmospheric pressure, reaction temperature 90 ℃, reaction time 12 h, n （ DMC ） ： n （ethanol） = 1：1 ,and [Bmim]Br dosage 2% of DMC mass. The catalyst still kept good catalytic activity after being reused three times.