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 TiOx 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.