In situ infrared spectroscopic studies of the Friedel-Crafts acetylation of benzene in ionic liquids using AlCl3 and FeCl3

In situ infrared spectroscopic studies have revealed that the mechanism of the Friedel-Crafts acetylation of benzene is exactly the same in ionic liquids as in 1,2-dichloroethane. The reaction of acetyl chloride with benzene in the presence of MCl3 (M = Al or Fe) in the ionic liquid 1-butyl-3-methylimidazolium chloride, ([bmim] Cl), leads to the formation of several key intermediates including the MCl3 adducts of the acetyl chloride, the acetylium ion [CH3CO](+)[MCl4](-), and the final product, the MCl3 adduct of acetophenone.