Magnetic hydroxyapatite-encapsulated γ-Fe2O3 nanoparticles functionalized with basic ionic liquids for aqueous Knoevenagel condensation

Hydroxyapatite-encapsulated gamma-Fe2O3 nanoparticles functionalized with diethyl aliphatic amine basic ionic liquids were synthesized and used as efficient magnetic catalysts for aqueous Knoevenagel condensation reactions. Quantitative conversion of the reactants was achieved under mild conditions; recycle of the catalyst, through convenient magnetic decantation, shows non-significant loss in activity. In comparison with the controlled experiments catalyzed by homogeneous basic ionic liquids and the basic ionic liquid-modified polystyrene resin, the excellent performance of the magnetic catalyst was attributed to the cooperativity between the base sites generated by framework HAP and the supported basic ionic liquids. (C) 2009 Elsevier B.V. All rights reserved.