Catalytic hydrogenolysis of aromatic ketones by a sol–gel entrapped combined Pd-[Rh(cod)Cl] 2 catalyst

Abstract

Co-entrapment of palladium nanoparticles and soluble [Rh(cod)(μ-Cl)] 2 in a silica sol–gel matrix forms a catalyst that promotes exhaustive hydrogenation and hydrogenolysis of various aromatic ketones. While the hydrogenation of acetophenone may proceed by initial formation of α-phenylethanol followed by dehydration to styrene and further reduction of the olefinic and aromatic CC bonds, the reaction of benzophenone and related compounds does not involve the intermediary of a carbinol. The immobilized combined catalyst is leach-proof and perfectly recyclable in at least five consecutive runs. Its unique catalytic activity is attributed to a synergistic effect between the different metal atoms.