Role of Re species and acid cocatalyst on Ir-ReOx /SiO2 in the C-O hydrogenolysis of biomass-derived substrates.

The catalytic performance of ReOx -modified Ir metal catalyst in the hydrogenolysis of C-O bonds is strongly dependent on the choice of solvent. The acidic property of the Re species becomes obvious in the alkane solvent, and the hydrogenolysis reaction proceeds mainly by acid-catalyzed dehydration and the subsequent metal-catalyzed hydrogenation. The acidic property of the Re species is weakened in water; however, the hydrogenolysis reaction proceeds in water via a direct mechanism involving SN 2-like attack of a hydride species at the interface between Ir and ReOx on the adsorbed Re alkoxide species. This mechanism enabled the selective dissociation of the C-O bond neighboring the CH2 OH group.