Post-Synthesis Modification of SSZ-35 Zeolite to Enhance the Selectivity in p-Xylene Alkylation with Isopropyl Alcohol.

Modification of textural and chemical properties of SSZ-35 was investigated in respect to the catalytic behavior of this zeolite in p-xylene alkylation with isopropyl alcohol. Acidic treatment of the external surface of SSZ-35 crystals resulted in a decrease in the void volume of the zeolite and in the concentration of acid sites mainly located on the external surface. This was evidenced from the FTIR spectra of adsorbed pyridine and 2,6-di-tert-butylpyridine. The modification caused a significant increase in the selectivity to 2,5-dimethylcumene while the p-xylene conversion decreased only very slightly. [ABSTRACT FROM AUTHOR]