Excellent catalytic properties over nanocomposite catalysts for selective hydrogenation of halonitrobenzenes

摘要

A partially reduced Pt/gamma-Fe2O3 magnetic nanocomposite catalyst (Pt/gamma-Fe2O3-PR) exhibited excellent catalytic properties in the selective hydrogenation of 2,4-dinitrochlorobenzene and iodonitrobenzenes.The selectivity to 4-chloro-m-phenylenediamine (4-CPDA),meto-iodoaniline (m-IAN),and para-iodoaniline (p-IAN) reached 99.9%,99.8%,and 99.4%,respectively,at complete conversion of the substrates.The hydrode-halogenation of 4-CPDA and LANs was fully suppressed for the first time over Pt/gamma-Fe2O3-PR.It was found that CO chemisorption on the Pt nanoparticles deposited on the partially reduced gamma-Fe2O3 and Fe3O4 nanoparticles was very weak,implying a weak tendency of the electronic back-donation from the Pt nanoparticles to the pi* antibonding orbitals of the adsorbed molecules.We believe that this is a cause of the superior selectivity to the haloanilines in the hydrogenation reactions of interest over the Pt/gamma-Fe2O3-PR catalyst.