Synthesis of Chalcones via Claisen-Schmidt Reaction Catalyzed by Sulfonic Acid-Functional Ionic Liquids

Four recyclable sulfonic acid-functional ionic liquids (Its) were prepared and used as dual catalyst and solvent for the synthesis of chalcones via Claisen-Schmidt condensation between acetophenone and benzaldehyde. All four Its proved to be very active, leading to an 85%-94% yield of chalcone in the presence of 20% ILs. The chalcones can simply be separated from mixtures by simple decantation. After removal of the water, the ILs can be readily recovered and reused successfully without any significant loss of catalytic activity, which are potential substitutes for conventional homogeneous/heterogeneous acidic catalysts.