Research on Coking Behavior over Catalysts for Toluene Disproportionation

Effects of pressure of toluene, reaction temperature and nature of catalysts on coking over catalysts in toluene disproportionation are studied by using the method of thermogravimetry. Experiment results show that during the toluene disproportionation, the coking amount over catalysts increases with partial pressure of toluene and reaction temperature and the initial coking temperature decreases with partial pressure of toluene. Coking results mainly from the relatively stronger acid sites on the surface of the catalyst. Both HZSM-5 and HM catalysts have efficiency for toluene disproportionation, but HZM-5 catalyst has higher catalytic activity and stability.