Poly(Vinylpyrrolidone)-Anchored Iridium Nanoparticles Supported on Al<sub>2</sub>O<sub>3</sub> as Ultra-Selective Catalyst for the Hydrogenation of <i>p</i>-Chloronitrobenzene

Poly (vinylpyrrolidone)-anchored iridium nanoparticles (PVP-Ir) were prepared via the reduction of H 2 IrCl 6 ·nH 2 O in ethanol/water mixtures. The catalytic properties of the colloidal nanoparticles that dispersed on Al 2 O 3 (PVP-Ir/Al 2 O 3 ) were investigated in the selective hydrogenation of p -chloronitrobenzene ( p -CNB) to p -chloroaniline ( p -CAN). The results indicated that the selectivity to p -CAN remained on the level of 100 % at complete conversion of p -CNB at lower temperature of 288 K. Moreover, the side reaction of hydrogenolysis of the carbon-halogen bond was completely inhibited in the absence of promoters and inhibitors. The great improvement on activity and selectivity of PVP-Ir/Al 2 O 3 was attributed to the highly and homogeneously dispersion of the iridium nanoparticles on the support Al 2 O 3 and the addition of appropriate amount of water in organic solvents