Multi-Layer Functionalized Poly(Ionic Liquid) Coated Magnetic Nanoparticles: Highly Recoverable and Magnetically Separable Brønsted Acid Catalyst

A functionalized poly(ionic liquid) coated magnetic nanoparticle (Fe 3 O 4 @PIL) catalyst was successfully synthesized by polymerization of functionalized vinylimidazolium in the presence of surface modified magnetic nanoparticles. The resulting heterogeneous catalyst is shown to be an efficient acidic catalyst for synthesis of 1,1-diacetyl from aldehydes under solvent free conditions and room temperature in high yields. Also, the catalyst shows good activity for the deprotection reaction of acylals. After completion of reaction, the catalyst was simply recovered by an external conventional magnet and recycled without significant loss in the catalytic activity. Because of the polymer layers coated surface of the magnetic nanoparticles, the catalyst has a good thermal stability and recyclability. The poly(ionic liquid) coated magnetic nanoparticles represents a novel class of heterogeneous catalyst which are particularly attractive in the practice of organic synthesis in an environmentally friendly manner.