离子液体催化合成5-叔丁基间二甲苯的研究

Synthesis of 5-tert-butyl m-xylene catalyzed by ionic liquid

合成酮麝香的重要中间体5-叔丁基间二甲苯的传统合成工艺存在酸催化剂回收利用困难、污染严重等问题。为了寻求新型绿色催化体系,合成了咪唑和季胺类功能性离子液体[Bmim]Cl-AlCl_(3)、[Bmim]Cl-FeCl_(3)、[Et_(3)NH]Cl-AlCl_(3)、[Et_(3)NH]Cl-FeCl_(3)。以[Bmim]Cl-AlCl_(3)离子液体为催化剂,考察了反应温度、n(间二甲苯)∶n(氯代叔丁烷)∶n(催化剂)、反应时间等对合成5-叔丁基间二甲苯的影响,并通过响应面法得出最优工艺条件:反应温度为13℃、n(间二甲苯)∶n(氯代叔丁烷)∶n(催化剂)=1∶1.2∶0.1、反应时间为73 min,此时5-叔丁基间二甲苯收率可达95%以上。

Traditional synthesis process for 5-tert-butyl-m-xylene,an important intermediate of ketone musk,has some problems such as difficult recovery of acid catalyst and serious pollution.In order to seek a novel green catalytic system,imidazole and quaternary amines functional ionic liquids such as[Bmim]Cl-AlCl_(3),[Bmim]Cl-FeCl_(3),[Et_(3)NH]Cl-AlCl_(3),[Et_(3)NH]Cl-FeCl_(3)are synthesized,and used to catalyze the synthesis of 5-tert-butyl-m-xylene through Friedel-Crafts alkylation reaction.Using[Bmim]Cl-AlCl_(3)ionic liquid as catalyst,the influences of reaction temperature,the molar ratio of m-xylene to tert-butane chloride to catalyst,reaction time and other technological conditions on the reaction are investigated,and response surface method is used to optimize the synthesis process.The obtained optimal conditions are as follows:reaction temperature is 13℃,n(m-xylene)∶n(tert-butane chloride)∶n(catalyst)=1∶1∶2∶0.1,and the reaction time is 73 min,under which the yield of 5-tert-butyl-m-xylene can exceed 95%.