离子液体催化苯与苄氯的烷基化合成二苯甲烷

Synthesis of Diphenylmethane by Alkylation Of Benzene with Benzyl Chloride by Ionic Liquid

摘要:

考察了离子液体催化Friedel–Crafts苄基化制备二苯甲烷，同时考察了AlCl3的摩尔分数、离子液体用量及不同离子液体等因素对苯与苄氯烷基化反应的影响。实验结果表明，离子液体的催化活性与其酸强度密切相关，酸性条件下离子液体才显示催化活性。AlCl3摩尔分数为66.7 %，催化剂（离子液体）用量3.3 g、反应温度80 ℃及常压反应条件下，1-丁基-3-甲基氯咪唑，N-丁基氯吡啶与AlCl3形成的离子液体具有较高的二苯甲烷选择性，分别为97.4 %和92.1 %。离子液体催化剂重复使用四次后，活性基本没有降低。

Abstract:

Diphenylmethane was prepared via Friedel–Crafts benzylation reaction over a series of ionic liquids as catalysts. The effects of the ratio of metal chloride to BmimCl or BpyCl, the amount of ionic liquids and different ionic liquids on the Friedel–Crafts benzylation were also investigated. The results showed that only the acidic ionic liquids had good catalytic activity, and the activity of ionic liquids correlated strongly with its acidity. The best yield of diphenylmethane for BmimCl-AlCl3 catalyst (97.4 %) and BpyCl-AlCl3 catalyst (92.1 %) were obtained with the mole fraction of AlCl3 66.7%, 3.3 g ionic liquid at 80 ℃ and atmospheric pressure. The ionic liquids could be reused four times without noticeable drop in activity.