Basic ionic liquids supported on hydroxyapatite-encapsulated γ-Fe2O3 nanocrystallites: An efficient magnetic and recyclable heterogeneous catalyst for aqueous Knoevenagel condensation

A series of basic ionic liquids functionalized hydroxyapatite-encapsulated γ-Fe2O3 magnetic nanoparticles were synthesized and characterized by XRD, XPS, HRTEM, IR and BET. These magnetic nanoparticles were used as efficient heterogeneous catalysts for aqueous Knoevenagel condensation under mild conditions and excellent results for extended substrates were obtained. In comparison with the control experiments, the high activity is ascribed to the cooperativity between the base sites generated by framework hydroxyapatite and supported basic ionic liquids. Separation of the catalyst from the reaction mixture was readily achieved by simple magnetic decantation and the catalyst could be easily recycled without appreciable loss of catalytic activity.

Graphical abstractA series of basic ionic liquids functionalized hydroxyapatite-encapsulated γ-Fe2O3 magnetic nanoparticles were used as efficient heterogeneous catalysts for aqueous Knoevenagel condensation under mild conditions. Separation of the catalyst from the reaction mixture is readily achieved by simple magnetic decantation and the catalyst could be easily recycled without appreciable loss of catalytic activity.Figure optionsDownload full-size imageDownload high-quality image (120 K)Download as PowerPoint slide