Synthesis of 5-benzoylacenaphthene in the presence of Lewis acidic ionic liquids

Acylation of acenaphthene with benzoyl chloride to 5-benzoylacenaphthene catalyzed by various Lewis acidic ionic liquids (ILs) was investigated. Ionic liquids of different alkyl chain length and metal chloride were synthesized and tested for the reaction to discuss the effects of Lewis acidity of the ionic liquid on the synthesis of 5-benzoylacenaphthene. Pure 5-benzoylacenaphthene was obtained and its structure was identified by GC/MS, FT-IR and 1H NMR spectra. [Emim]Cl/AlCl3 ionic liquid was found to be the most active catalyst in the acylation. The yield of 5-benzoylacenaphthene was up to 87% and the regio-selectivity towards 5-benzoylacenaphthene was up to 90%. The experimental resulted show that [Emim]Cl/AlCl3 can be used as both catalyst and solvent, and it is reusable and environmentally friendly for the preparation of 5-benzoylacenaphthene.