Kinetics of the liquid-phase cooxidation of cyclohexane and cyclohexanone over supported cerium oxide catalysts

The liquid-phase cooxidation of cyclohexane and cyclohexanone over supported cerium oxide catalysts prepared with two different impregnation methods has been studied thorough ly in a batch autoclave using glacial acetic acid as the solvent. Under identical ceria loading, the catalyst prepared with multi-impregnation method has a higher activity than that with conventional impregnation method. Some of the catalyst's characters have been discussed to elucidate the effect of the impregnation method on the activity and product selectivity. Reaction parameters, such as the reaction temperature, catalyst loading, initial concentration of cyclohexane and cyclohexanone, molar ratio of cyclohexane/cyclohexanone affect the reaction rate and the product selectivity while the oxygen partial pressure only has a mild effect on the reaction rate as it exceeds 12.5 atm. Empirical rate expressions which correlate the initial reaction rates of cyclohexane and cyclohexanone with the initial concentrations of cyclohexane and cyclohexanone are drawn.