Recyclable carbon supported copper-manganese oxide for selective aerobic oxidation of alcohols in combination with 2,2,6,6-tetramethylpiperidyl-1-oxyl under neutral condition

Abstract

Due to the promotion of the surface area and the dispersion of active components upon supporting mixed metal oxides on the porous material active carbon, the copper-manganese oxide on carbon system has been proven to be much more efficient than the co-precipitation prepared Cu-Mn oxide in mediating the 2,2,6,6-tetramethylpiperidyl-1-oxyl (TEMPO)-catalyzed aerobic oxidation of alcohols. Even at 30°C and with a 0.1 mol% load of TEMPO, the oxidations proceeded smoothly. Upon catalysis with the Cu-Mn oxide/C (10 wt%) and TEMPO (0.5-5 mol%), various alcohols were oxidized selectively to the corresponding aldehydes or ketones with molecular oxygen at 80°C. Such a stable, recyclable heterogeneous cocatalyst permits alcohols to be oxidized under neutral and mild conditions. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.