STUDIES ON CATALYSTS FOR THE AYKYLBENZENE REACTION .12. MECHANISM OF ACTIVATION OF WATER IN STEAM DEALKYLATION OF ALKYLBENZENE OVER RH-MGWO4 CATALYST

The mechanism of activation of water in the steam dealkylation of m-xylene was investigated by the use of a pulse reactor. In the activation of H2O over Rh/Al2O2 catalyst the formation of active surface OH groups occurs. It was demonstrated that the mechanism of activation of H2O over Rh/MWO4 (M = Mg, Ca and Sr) differs from that over Rh/Al2Oa catalyst. Namely, the activation over Rh/ MgWO4 brings about the cleavage of H2O molecule into gaseous H2 and surface oxygen atom. The high reactivity of this surface oxygen on Rh/MgWO4 catalyst seemed to be responsible for the high steam-dealkylating activity of this catalyst. Thus, the mechanism of activation of H2O in the steam dealkylation of alkylbenzene over Rh/MWO4 catalyst is well expressed by the following two equations. © 1979, The Chemical Society of Japan. All rights reserved.