复合型质子酸性离子液体协同催化异丁烯齐聚反应

Oligomerization of isobutene catalyzed by combined proton acidic ionic liquids

合成1-(4-磺酸丁基)-3-甲基咪唑三氟甲磺酸盐([NNS][CF3SO3])和1-(4-磺酸丁基)-3-甲基咪唑硫酸氢盐([NNS][HSO4])两种质子酸性的咪唑基离子液体,应用于催化异丁烯齐聚反应,深入研究离子液体种类及反应条件、两种离子液体的复配摩尔比和搅拌方式对催化活性、二聚体C 8=产品的选择性和催化剂循环稳定性的影响,并利用核磁探讨反应进程。结果表明:在催化剂用量5mmol、温度100℃、反应时间3h、两种离子液体复配摩尔比1∶1时,催化活性和二聚产物C 8=的选择性最高,异丁烯的转化率最高达84%,C8=选择性为77%;改进搅拌方式后,催化剂循环稳定性得到明显提高,稳定循环达6次,异丁烯转化率保持在70%以上,C 8=选择性高达90%以上。

Two proton acidic imidazolium-based ionic liquids(ILs)of 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate([NNS][CF3SO3])and 1-(4-sulfobutyl)-3-methylimidazolium hydrosulfate([NNS][HSO 4]),were synthesized and applied in the oligomerization of isobutene.Some important parameters,including the types of ionic liquids,amount of catalysts,the reaction temperature,the reaction time,molar ratios of two ILs,stirring method and speeds,were screened.The optimized reaction conditions were determined as follows,5 mmol of catalyst,100℃,3 h,and molar ratio of 1∶1 for the two ILs.Under these conditions,the catalytic activity of the complexed ILs reached the highest with conversion rate of 84%for isobutene and selectivity of 77%for C8=.The complex ILs could be recycled six times without obvious loss of catalytic activities,and conversion rate of isobutene remained 70%with above 90%selectivity of C8=.The reaction was monitored on NMR and the formation process was further determined.