Selective hydrogenation of nitrocyclohexane to cyclohexanone oxime with H2 on decorated Pt nanoparticles

A Pt catalyst has been designed to convert nitrocyclohexane into cyclohexanone oxime under mild hydrogenation conditions (4 bar of H2, 383 K, and solvent-free media). It has been found that the partial reduction of the nitro group to the oxime function is promoted by Pt nanoparticles decorated with TiO x species, being cyclohexanone the main undesired by-product. A reaction scheme has been proposed that explains the process and active sites involved with the formation of the different reaction products. Based on that, a further chemical modification of the catalyst with sodium cations has allowed to increase the selectivity to cyclohexanone oxime to ∼85% at 95% conversion. The final catalyst can be recycled and TON values of, at least, 13,000 can be obtained.