高岭土负载ZnCl2催化Friedel-Crafts烷基化反应

以高岭土为原料,经酸化及负载ZnCl2得到固体酸催化剂,采用XRD、NH3 -TPD等测试技术对催化剂进行表征,并考察了其对苯苄基化合成二苯甲烷的催化性能.结果表明,焙烧温度对催化剂的活性有显著的影响,300℃为适宜的焙烧温度,XRD结果显示在此烙烧温度下ZnCl2与高岭土相互作用产生新的晶相,NH3 -TPD的结果表明高岭土负载ZnCl2后表面产生一个新的中等强度的酸中心,并且总酸量显著增加.在苯与氯化苄物质的量比为5∶1,催化剂用量为3wt％,60℃反应3h的最优条件下,二苯甲烷的收率达76.5％.

Friedel-Crafts alkylation reaction catalyzed by kaolinite supported ZnCl2

The composites of ZnCl2 supported on acid-treated kaolinite were prepared,characterized by XRD and NH3-TPD and evaluated as solid acid catalysts for Friedel-Crafts benzylation of benzene.Results showed that activation temperature of the catalyst played an important role in the catalytic performance and 300 ℃ was the optimum temperature.XRD revealed that a new phase was formed in the catalyst during the calcination process at 300 ℃ and NH3-TPD revealed that in the acid-treated kaolinite,introduction of ZnCl2 generated a new medium strength acid site and total acid amount significantly increased.Under the optimal conditions(molar ratio of benzene to benzyl chloride=5:1,amount of catalyst=3 wt% of total reaction mixture,60 ℃,3 h),the yield of diphenylmethane reached 76.5%.