Covalently anchored tertiary amine functionalized ionic liquid on silica coated nano-Fe₃O₄ as a novel, efficient and magnetically recoverable catalyst for the unsymmetrical Hantzsch reaction and Knoevenagel condensation

A novel magnetic nanoparticle supported basic ionic liquid was successfully prepared by covalently anchoring 1-(2′-piperidyl)ethyl-3-(3-propyltriethoxysilane)imidazolium chloride onto the surface of silica-coated Fe₃O₄ nanoparticles, and characterized by FT-IR, TEM, XRD, TGA, VSM and elemental analysis. The obtained supported ionic liquid was certified as a versatile and robust catalyst for the unsymmetrical Hantzsch reaction and Knoevenagel condensation under solvent-free conditions. Furthermore, the catalyst could be conveniently recovered by an external magnet and reused six times without significant loss of catalytic activity.