Catalytic consequences of hydroxyl group location on the kinetics of n-hexane hydroisomerization over acidic zeolites

摘要: Abstract The measured kinetics of n-C6H14 hydroisomerization reactions is consistent with a bifunctional mechanism involving the facile dehydrogenation n-hexane on metal catalyst and kinetically relevant step isomerization n-hexene zeolitic acidic sites. activation entropy in small 8-MR pockets MOR (−35 J mol−1 K−1) similar to that larger 12-MR channels (−37 J mol−1 K−1) BEA (−33 J mol−1 K−1) but higher than medium pore FER (−86 J mol−1 K−1), suggesting partial confinement C6 olefinic reactants results lower free energy for reaction MOR. hypothesis cyclopropane-like cationic transition state not completely contained within observed selectivity 2-methylpentane 3-methylpentane being identical BEA. compared may arise due greater electrostatic stabilization positively charged by framework oxygen atoms located mouth smaller or heat adsorption caused pockets. comparable loss mediated rate per proton five times These provide another conceptual consideration rigorous quantitative understanding local environment effects zeolite channel size connectivity acid-catalyzed reactions.