EFFECTS OF SIO2 AL2O3 RATIO OF H-MORDENITE ON ENCAPSULATED PRODUCTS INSIDE THE PORES IN SHAPE-SELECTIVE ISOPROPYLATION OF BIPHENYL/

The effects of SiO2/Al2O3 ratio of H-mordenite on the selectivity of e ncapsulated products in the pores and of bulk products were investigat ed in the isopropylation of biphenyl. The selectivity of 4,4'-diisopro pylbiphenyl (4,4'-DIPB) of bulk products was varied with SiO2/Al2O3 ra tio. Highly dealuminated H-mordenite gave a selectivity higher than 80 %, whereas the selectivity was low for H-mordenite with SiO2/Al2O3 rat io of 10-20. On the other hand, the selectivity of 4,4'-DIPB in encaps ulated DIPB isomers was higher than 85% for all H-mordenites regardles s of SiO2/Al2O3 ratio. These results show that all H-mordenites cataly ze the isopropylation of biphenyl with high shape-selectivity inside t he pore. The low selectivity of 4,4'-DIPB in bulk products for H-morde nites with low SiO2/Al2O3 ratio was not due to a lack of shape-selecti vity of the H-mordenites, but to non-regioselective isopropylation at the external acid sites. Non-regioselective catalysis over H-mordenite with low SiO2/Al2O3 ratio could be induced by choking pores by coke d eposition.