离子液体催化苯与苄氯的烷基化合成二苯甲烷

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3.3g、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4次后,活性基本没有降低。

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

Diphenylmethane was prepared via the 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 a good catalytic activity,and the activity of ionic liquids could be 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.