Pd Nanoparticles in Ionic Liquid Brush: A Highly Active and Reusable Heterogeneous Catalytic Assembly for Solvent-Free or On-Water Hydrogenation of Nitroarene under Mild Conditions

A heterogeneous catalytic assembly of Pd nanoparticles-in-SiO 2 supported ionic liquid brushes has been developed. The catalytic assembly showed uniform Pd particles size distribution. The catalyst allowed the hydrogenation of nitrobenzenes to arylamines to proceed under solvent-free or in neat water, room temperature, and normal pressure, giving nearly 100% yield and selectivity. A clean and energy-efficient process can be thus created over the robust catalysts. The process employing such a catalytic assembly overcomes simultaneously the disadvantages of the requirement for organic solvents in the liquid hydrogenation process and for high temperature in the vapor hydrogenation process.