Regulation of the selective hydrogenation performance of sulfur-doped carbon-supported palladium on chloronitrobenzene

Abstract

The overall performance of metal catalysts can be efficiently adjusted by modifying carbon carriers with different valence sulfur precursors. The wet impregnation technique successfully prepared carbon material carriers doped with varying sources of sulfur (Na2SO4, NaHSO3, Na2S·9H2O). Palladium carbon catalysts doped with different sulfur precursors had been prepared with the aid of the liquid-phase reduction method of the selective hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN). The catalyst prepared for Na2S·9H2O as a precursor has excellent performance, and the selectivity for o-CAN is more than 99.9% at 100% conversion. In addition, the characterization results show that with the decrease of S valence, the electronic effect between S and Pd increases, and the outer electron shift of Pd increases, which reduces the adsorption and dissociation ability of Pd to hydrogen, resulting in excellent selectivity. The effects provided a good idea for the hydrogenation of o-CNB and a different point of view on sulfur doping in a variety of hydrogenation reactions.