Kinetic modeling and laboratory investigation of catalytic toluene methylation to para-xylene

Since catalytic toluene methylation is one of the most significant processes in petrochemical industries, improving its related factors, such as synthesizing new catalysts with better characteristics, is vitally important. In this study, mesoporous acidic Al-HMS(x) catalyst with different Si/Al ratio was synthesized by sol-gel method, and then X-ray diffraction, Temperature programmed desorption of ammonia (NH₃-TPD), and Brunauer–Emmett–Teller (BET) techniques were used for catalyst characterization. Synthesized catalyst was utilized for para-xylene production from toluene methylation reaction in a vertical, fixed-bed reactor. Al-HMS (5) shows the best para-xylene selectivity and methanol conversion among the Al-HMS(x) materials. Experimental data were compared with different reaction rate equations, and Ramakirishna et al. model shows a good agreement with our experimental findings. Mathematical modeling was applied to achieve conversion profile versus temperature and reactor volume.