摘要
采用乙腈探针红外光谱法测定了 [bmim]Cl/AlCl3 类离子液体的酸性 .结果表明 ,乙腈可以区分离子液体的酸类型(Br¨onsted酸或Lewis酸 ) ,同时可以指示离子液体的Lewis酸强度 .使用 [bmim]Cl/AlCl3 类离子液体催化二苯醚与十二烯的烷基化反应 ,研究了离子液体的酸强度、反应温度和醚烯比对反应的影响 ,并与AlCl3 催化体系进行对比 .结果发现 ,该离子液体对二苯醚与十二烯烷基化反应的催化活性明显高于AlCl3 .使用离子液体作催化剂显著提高了烷基化反应的产率 ,简化了产物的分离与提纯 ,且对环境友好 .当控制反应温度为 80℃ ,原料醚烯摩尔比为 7,并采用酸强度适中的离子液体时 ,目标产物单十二烷基二苯醚的产率接近 90 % .
Acetonitrile has been used as a probe molecule to determine the acidity of ionic liquids. Based on the information from IR spectra in the CN stretching region of 2?200 ～ 2?400 cm -1 , Lewis and Brnsted acidity of ionic liquids can be distinguished from each other, and Lewis acid strength of ionic liquids can be estimated. This method is easy to handle and widely applicable to both liquid and solid acids. The Lewis acid strength of ionic liquids can be adjusted with AlCl 3. The synthesis of monoalkyldiphenyl oxide via the alkylation of diphenyl oxide with dodecene catalyzed by 1 butyl 3 methylimidazolium chloroaluminate (Ⅲ) (Cl/AlCl 3) was studied. The catalytic activity of Cl/AlCl 3 is much higher than that of the AlCl 3 catalyst. A low amount of Cl/AlCl 3 dramatically improves the monoalkyldiphenyl oxide yield. A high yield of monoalkyldiphenyl oxide of about 90% can be obtained at a reaction temperature of 80 ℃ and a diphenyl oxide to dodecene molar ratio of 7. The process catalyzed by the ionic liquids simplifies the product isolation evidently and can be regarded as an environmentally benign system.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2004年第1期44-48,共5页
基金
国家重点基础研究发展规划 (973计划 )资助项目 (G2 0 0 0 0 480 0 2 )
关键词
离子液体
酸性
乙腈探针
红外光谱法
二苯醚
十二烯
烷基化反应
ionic liquid, acidity, acetonitrile probe, infrared spectroscopy, diphenyl oxide, dodecene, alkylation
