Efficient synthesis of 1-acetylpyrene using [Bmim]Cl-FeCl3 ionic liquid as dual catalyst and solvent

Friedel-Crafts acylation of pyrene with acetic anhydride to 1-acetylpyrene catalyzed by three metal chloride and three Lewis acidic ionic liquids (ILs) containing 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and different metal chloride was investigated. ILs were prepared and tested for the acylation to explore the effects of Lewis acidity of ILs on the synthesis of 1-acetylpyrene. [Bmim]Cl-FeCl3 was found to be the most suitable catalyst, and the possible pathway for the acylation of pyrene with acetic anhydride catalyzed by [Bmim]Cl-FeCl3-IL was discussed. Pure 1-acetylpyrene was obtained and its structure was identified by gas chromatography-mass spectrometer, Fourier transform infrared and H-1 NMR spectra.