Alkylation of o-xylene with styrene over modified mordenite for environmentally friendly synthesis of PXE

Effects of hydrochloride acid dealumination of mordenite (MOR) catalysts for the synthesis of 1-phenyl-1-xylyl ethane (PXE) were investigated. The structure and acidity of catalysts were characterized by XRD, BET, XRF, FT-IR, 27A1 NMR and NH₃-TPD techniques. The catalytic performance of the acid-treated MOR zeolites was studied through using the alkylation of o-xylene with styrene. The test results showed that the strength of remaining Bransted acid sites increased despite the reduction of total number of acid sites after dealumination, and the micropores of HMOR were slightly enlarged coupled with the formation of secondary mesopores. Additionally, the modified HMOR zeolites showed longer catalyst life with the styrene conversion rate retained. Among the catalysts employed in this study, the modified mordenite that was dealuminated by HC1 (2 mol/L) could be used repeatedly without significant loss of activity and selectivity during six catalytic runs, which have been ascribed to its specific acidity and structural properties.