Catalytic Transformation of Toluene over High Acidity Y-Zeolite Based Catalyst

Catalyst S. Al-Khattaf* Chemical Engineering Department, King Fahd University of Petroleum & Minerals Dhahran 31261, Saudi Arabia Abstract Catalytic transformation of toluene has been investigated over Y-zeolite based catalysts in a novel riser simulator at different operating conditions. A number of experiments were carried out in the temperature range of 400-500C to understand the transformation of toluene over high acidity Y-based zeolite catalyst (H-Y). It has been observed that toluene can transform either through disproportionation producing benzene and xylene isomers or through dealkylation producing gases and benzene. The rate of both reactions essentially depends on reaction temperature. Dealkylation reaction was found to be favored by high temperature. The benzene/xylene ratio was found to increase with temperature due to the high xylenes dealkylation rate. Toluene transformation was found to be controlled by both Y-zeolite acidity and reaction temperature. While high acidity and high reaction temperature favor toluene dealkylation, medium acidity and low reaction temperature favor toluene disproportionation. Pseudo-homogenous first order kinetic was used to model toluene conversion. Two different deactivation functions were included in this model and the kinetic constants were calculated based on these two different functions.