Recyclable Magnetic Fe<sub>3</sub>O<sub>4</sub> Nanoparticle-Supported Chloroaluminate Ionic Liquids for Heterogeneous Lewis Acid Catalysis
Rajkumar Kore, Anand D. Sawant, Robin D. Rogers
Abstract
In our efforts to overcome the limitations in using ionic liquids (ILs) as homogeneous catalysts, we prepared a heterogeneous analog by loading 10–40 wt% [HN222][Al2Cl7] ([HN222]+ = triethylammonium) onto Fe3O4 nanoparticles (NPs) to obtain free-flowing solid catalysts. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), and Brunauer–Emmett–Teller (BET) surface area analysis of 20% [HN222][Al2Cl7]/Fe3O4, all confirmed loading of the IL. Catalytic performance was assessed with the alkylation of benzene with benzyl chloride reaction, and 20% [HN222][Al2Cl7]/Fe3O4 was found to be the best catalyst with 100% conversion and 77% product selectivity. The catalyst was also found to be active for alkylation of other substrates such as toluene and o-, m-, and p-xylene. Utilizing a magnet for separation, the catalyst could be recycled and reused for five runs without loss of catalytic activity.