Catalytic allylic oxidation of cyclohexene with air over

Abstract

Catalytic allylic oxidation of cyclohexene with air to 2-cyclohexen-1-one and 2-cyclohexen-1-ol over Co/Al₂O₃ catalysts under mild conditions has been reported. A series of transition metal-containing Al₂O₃ samples such as Co/Al₂O₃, Ni/Al₂O₃, Cu/Al₂O₃, Fe/Al₂O₃ and Cr/Al₂O₃, have been prepared by wet impregnation of powdered pseudo-boehmite (Al₂O₃) support with aqueous metal-containing salt solutions, followed by drying at 413 K overnight and calcination at 823 K for 6 h. Only Co/Al₂O₃ shows good activity for the selective oxidation of cyclohexene by air to 2-cyclohexen-1-one and 2-cyclohexen-1-ol in DMF. Under identical conditions, 34.3 mol% of cyclohexene is catalytically converted by Co/Al₂O₃ to achieve 73.0% selectivity to 2-cyclohexen-1-one and 23.9% selectivity to 2-cyclohexen-1-ol, which is superior to other catalysts.