Catalytic Alkylation Routes via Carbonium-Ion-Like Transition States on Acidic Zeolites



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Zeolites going crackers: Brønsted acid sites in zeolites (H-FER, H-MFI, H-MOR) catalyze CH4-alkene reactions at high temperatures (>700 K) via carbonium-ion-like transition states. The ratio of rate constants for forward and reverse reactions (alkane alkylation-cracking, alkene dimerization-cracking) equal their respective equilibrium constants (KR). In contrast, relative rates of CH4 and alkene reactions with a given alkoxide are influenced by the local environment around acid sites.