Pore structure and shape-selectivity in the isopropylation of biphenyl catalyzed by one-dimensional large pore zeolites

Abstract Why and where shape-selective catalysis occurs over large pore zeolites are discussed from relationships between pore structure and shape-selectivity in the isopropylation of biphenyl (BP) over zeolites: H-mordenite (HM), ZSM-12, SSZ-31, SSZ-24, and SSZ-42 with one-dimensional twelve membered ring, and UTD-1 and C1T-5 with one-dimensional fourteen membered ring. HM is the best fitted for the shape-selective isopropylation of BP to form 4,4'-diisopropylbiphenyl (4,4'-DIPB). However, the selectivity for 4,4'-DIPB was lower for other zeolites. The steric restriction with the pores differentiates the transition states to form DIPB isomers, and the transition state which fits the pore enhances the formation of 4,4'-DIPB.