OXYDEHYDROGENATION OF CYCLOHEXANOL OVER CARBON CATALYSTS

The reaction of cyclohexanol over carbon catalysts with surfaces of di fferent chemical nature was studied. The catalyst samples were prepare d by treating a parent activated carbon with HNO3, H2O2, O-2 and N2O. The catalytic tests were performed in a packed-bed reactor at 350 degr ees C. Dehydration as well as dehydrogenation of the substrate occur u nder the reaction conditions. The main products obtained are cyclohexe ne, cyclohexanone, benzene and phenol. Dehydration occurs preferential ly over the carbon treated with HNO3, while the best selectivity to cy clohexanone is achieved with the carbon treated with H2O2. The catalys t sample treated with N2O is highly selective to phenol. A mechanism i nvolving nitro groups on the carbon's surface is proposed. (C) 1998 El sevier Science Ltd. All rights reserved.