Aerobic oxidation of alcohols over carbon nanotube-supported Ru catalysts assembled at the interfaces of emulsion droplets

Carbon nanotube (CNT)-supported ruthenium catalysts, assembled at the interfaces of emulsion droplets, show excellent activity, selectivity, and stability for the selective oxidations of benzyl alcohol to benzaldehyde with oxygen or air as oxidant in the presence of water. The selective oxidation of benzyl alcohol over Ru/CNTs catalysts is greatly enhanced and quickened due to the presence of water. A reaction pathway is proposed, in which the promotion effect of water on the catalytic activity of Ru/CNTs is discussed. The as-made Ru/CNTs catalysts are also active for the aerobic oxidation of a variety of alcohols with a sulfur or nitrogen atom or a carbon-carbon double bond in the multiphase reaction system. Moreover, after the reactions, the catalysts can be easily separated and recycled by sedimentation. (C) 2010 Elsevier B.V. All rights reserved.