碱性离子液体催化碳酸乙烯酯甲醇酯交换合成碳酸二甲酯

摘要

A series of imidazolium-based ionic liquids with different anions have been synthesized by ion exchange technique and characterized by Fourier transform infrared spectrum. To probe their catalytic performance, transesterification reactions between ethylene carbonate (EC) and methanol for the synthesis of dimethylene carbonate (DMC) have been carried out. The catalytic results indicated that, among various imidazolium-based ionic liquids employed, l-butyl-3-ethylimidazolium hydroxide ([BmIm] OH) demonstrated superior catalytic performance to other ionic liquids. The conversion of EC and selectivity of DMC could be up to 88. 5% and 90. 3% respectively, and catalytic activity could reach its maximum under the optimal reaction conditions that a ratio of MeOH/EC = 10 : 1, catalysts dosage was 0. 3 g and reacted at 67 ℃ for 4 h. The [Bmlm] OH catalyst could still keep a moderate catalytic activity after five consecutive running tests.%使用离子交换法制备了不同阴离子的咪唑盐离子液体,并通过FT-IR手段对所合成样品进行了表征.以碳酸乙烯酯(EC)与甲醇(MeOH)酯交换合成碳酸二甲酯(DMC)反应,比较了相同催化条件下不同阴离子咪唑盐的催化性能.结果表明:1-丁基-3-甲基咪唑氢氧化物([BmIm] OH)对EC与MeOH酯交换反应表现出优异的催化性能.在反应时间为4h,温度为67℃,催化剂0.3g,醇酯比为10:1的条件下,EC的转化率和DMC的选择性分别高达88.5％和90.3％.经重复使用5次后,催化剂仍能保持较好的催化活性.