咪唑类氯铝酸离子液体的L ew is酸性和极化能力对苯烷基化反应性能的影响

Effect of Lewis Acidity and Polarizability of Imidazole-Based Chloroaluminate Ionic Liquids on the Catalytic Performance for the Alkylation of Benzene

合成了不同烷基和卤素取代的咪唑类氯铝酸离子液体([Rm im]X/A lC l3),用电喷雾-离子化质谱和红外光谱表征了离子液体的分子结构、Lew is酸性和极化能力,并将这些性质与离子液体在苯与1-十二烯烷基化反应中的催化性能进行关联。实验结果表明,对于咪唑类氯铝酸离子液体,[Bm im]+A l2C l6B r-具有适宜的Lew is酸性和极化能力,[Bm im]+A l2C l6B r-与1-十二烯的摩尔比为0.005时,1-十二烯的转化率可达93.2%,2-烷基苯的选择性为37.7%。

A series of imidazole-based chloroaluminate ionic liquids with different alkyl and halogen substituents were prepared, and characterized by means of electrospray ionized-mass spectrometry (ESI-MS) and infrared spectroscopy (IR) techniques to investigate molecular structure, Lewis acidity and polarizability of ionic liquids which were correlated with their catalytic performance in benzene alkylation. [Bmim]+ Al2Cl6Br- had proper Lewis acidity strength and polarizability, and best catalytic activity in benzene alkylation among all imidazole-based chloroaluminate ionic liquids. Conversion of 1-dodecene 93.2% with 2-dodecylbenzene selectivity 37.7% was obtained when n([Bmim]+Al2Cl6Br-) : n(1-dodecene) was 0.005.