SHAPE-SELECTIVE ALKYLATION OF BIPHENYL OVER MORDENITE - CERIUM EXCHANGED SODIUM MORDENITE AND UNMODIFIED H-MORDENITE WITH LOW SIO2 AL2O3 RATIO/

Liquid phase isopropylation of biphenyl with propylene was studied ove r a cerium exchanged sodium mordenite (Ce/NaM25) and a H-mordenite (HM 25) with the same SiO2/Al2O3 ratio of 25. Shape-selective catalysis oc curred to give 4,4'-diisopropylbiphenyl (4,4'-DIPB) in high selectivit y over Ce/NaM25 under any propylene pressures. HM25 gave 4,4'-DIPB sha pe-selectively under high propylene pressures. However, the reaction w as severely deactivated at a conversion of ca. 60% under such a low pr essure as 0.8 kg/cm2 because of coke formation in the pore. The yeilds of 4-isopropylbiphenyl (4-IPBP) and 4,4'-DIPB decreased with the incr ease of those of 3-IPBP and 3,4'-DIPB because of non-selective alkylat ion and isomerization at external acid sites that are alive in spite o f severe deactivation. No significant isomerization of 4,4'-DIPB over Ce/NaM25 was observed even at low propylene pressure. In the case of H M25, the isomerization of 4,4'-DIPB to 3,4'-DIPB occurred significantl y under low propylene pressures, while it decreased under high pressur e. These differences are ascribed to the differences of nature of acid sites between Ce/NaM25 and HM25 zeolites.