Isopropylation of 4-isopropybiphenyl to 4, 4'-diisopropylbiphenyl over alkalis and acid modified mordenite zeolites

Isopropylation of 4-isopropybiphenyl to 4, 4'-diisopropylbiphenyl was carried out over hierarchical mesoporousmordenite zeolites through alkalis modification of H-mordenite zeolite in a fixed-bed reactor. In order to investigate the effects of the pore structure and the acid sites of the zeolite samples on the catalytic properties, the parent and modified zeolite samples were thoroughly characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), ammonia temperature programmed desorption (NH₃-TPD), and N₂ physical adsorption-desorption. The results showed that the alkalis treatment adapted the pore structure, and the acid strength and amount without obvious destruction to the MOR topological structure. This adaption was contributed to the improvements of 4-isopropybiphenyl conversion and reaction stability. Modifying the sample with alkalis first and then followed by an acid treatment was in favor of removing the extra-framework alumina from the alkalis treatment and adapting the acid sites on the extra surface of the sample, which can successfully improve the selectivity of 4, 4'-diisopropylbiphenyl.