The Application Of Lewis Acidic Ionic Liquids Catalyst In Friedel-Crafts Reaction

Ionic liquids have recently gained recognition as environmentally benign catalyst in various chemical processes.They have high thermal stability and tunable physical and chemical properties by the choice of organic cation and inorganic anion,etc.Until now,ionic liquids have been applied in organic syntheses widely.Concrete contents discussed in this dissertation are as follows:1.Chloroferrate ionic liquid was immobilized on mesoporous silica of MCM-41 via a two-steps process,in which 1-trimethoxysilylpropyl-3-methylimidazolium chloride-FeCl₃ was synthesized and grafted onto siliceous MCM-41.The obtained immobilized ionic liquid was used as catalyst in the Friedel-Crafts reaction of benzyl chloride with benzene to synthesize diphenylmethane.This solid acidic catalyst could be recycled for ten times in the reaction without loss in activity.The yield of monoalkyl product in the tenth recycle was as high as 94.1%.It should be noted that the ratio of ionic liquid moiety to benzyl chloride is 1.0 mol.%for the catalyst,which is much lower than that of the corresponding pure BmimCl-FeCl₃.2.Chloroindate ionic liquid was immobilized on siliceous MCM-41. The effects of molar ratio of benzene to benzyl chloride,amount of catalyst,reaction time and temperature,and existence of H₂O on the reaction of benzyl chloride with benzene were investigated systematically. It was found that,besides the merits observed in the catalytic system of above immobilized chloroferrate ionic liquid,such immobilized ionic liquid is not sensitive to water.3.A series of Lewis acidic ionic liquids were synthesized by combining FeCl₃,AlCl₃ or ZnCl₂ with BmimCl and used as Lewis acidic catalyst in the reaction of benzene with CCl₄.The effect of reaction time, temperature,molar ratio of benzene to methane tetrachloride,amount of ionic liquids and the acidity strength on the reaction were investigated.