Photocatalytic selective aerobic oxidation of amines to nitriles over Ru/γ-Al2O3: the role of the support surface and the strong imine intermediate adsorption

Hydroxyl coordinated ruthenium dispersed on the surface of gamma-Al2O3 can be applied to the selective oxidation of amines with light irradiation and an atmospheric pressure of O-2 at room temperature. Sunlight is also an effective light source for the selective aerobic oxidation of primary amines to corresponding nitriles. The high photocatalytic activity and selectivity over Ru/gamma-Al2O3 originate from the adsorption of amines and imine intermediates on the abundant surface OH groups of the photocatalyst and further formation of Ru-amide species by ligand exchange of adsorbed amines and imine intermediates with adjacent exposed active Ru sites. Light is introduced to the system successfully via the formation of Ru-amide species, which are used as the light absorption sites of the photocatalytic selective oxidation of amines. Primary amines are directly converted to corresponding nitriles via a two-step oxidative dehydrogenation process.