LAUSR

Abstract In this work, an efficient and benign approach for highly selective preparation of cyclohexanone oxime from the liquid-phase oxidation of cyclohexylamine with dioxygen employing supported WO3/γ-Al2O3 as bifunctional catalyst under solvent-free conditions has been developed. The results demonstrated that the bifunctional supported WO3/γ-Al2O3 catalyst played an important role in the oxidation reaction, and 31.4% of cyclohexylamine conversion and 83.2% of selectivity to cyclohexanone oxime were obtained over 10%WO3/γ-Al2O3. Moreover, the possible reaction pathway over supported WO3/γ-Al2O3 catalyst was suggested. It was confirmed that WO3 acted as activating molecular oxygen and the surface hydroxyl groups of γ-Al2O3 were responsible for the adsorption activation of cyclohexylamine. This method for preparation of cyclohexanone oxime from cyclohexylamine is a promising process employing molecular oxygen as green oxidant and inexpensive WO3/γ-Al2O3 as bifunctional catalyst under mild conditions.