Highly selective IrMo/TiO2 catalyst for hydrogenation of nitroarenes

The performance of many supported metal catalysts is markedly enhanced by promoters. Here, we demonstrate the introduction of Mo into TiO2-supported IrMo catalysts greatly boosts the 3-vinylaniline (3-VA) selectivity of the hydrogenation of 3-nitrostyrene (3-NS). With the rise of Mo component in IrMo/TiO2 catalysts, the Ir that activate H2 are surrounded by more Mo species and become more oxidized, which prevents flat adsorption of 3-NS on Ir; meanwhile, Mo(V) species that are favorable for activation of nitro group of 3-NS increase, thus the synergistic effect affords excellent 3-VA selectivity. The optimal catalyst 1Ir9Mo/TiO2 displays 99.8% selectivity of 3-VA at a 100% conversion. It also shows good recyclability and universality in selectively reducing unsaturated nitroarenes to corresponding anillines with exceptional selectivity.