Abstract:
The valuable chemical synthesis of shape selective zeolites is an industrial importance. Para-xylene has been synthesized over pore size regulated zeolites by toluene disproportionation reaction. Effects of catalytic parameters, i.e. temperature, Si/Al molar ratio, pore size and external surface acidity of the zeolites are studied to determine the behavior of the reaction. Zeolites used in this work are prepared directly from silatrane and alumatane via sol-gel process and microwave technique. The results from the reaction are measured in terms of conversion, selectivity and product distribution. Modifications of H-ZSM-5 zeolites carried out by method of chemical vapor deposition (CVD) of tetraethoxysilane (TEOS) and Silicalite shell modification (Seeding) are used to passivate non-selective acid sites at the external surface and thereby reduce the non-selective surface reactions. Effect of Si/Al ratio on the amount of silica deposited of CVD and dilution effect for seeding are also investigated.
