Influence of the Acid Reactivity of Carbenium Ions in Zeolites on the Methanol-to-Olefins Process.

Carbocations are typical intermediates in acid catalyzed reactions in organic chemistry synthesis. Confinement within the framework of zeotype materials distinguishes the function of carbenium ions as catalytic centers in various chemical processes. A selective and reversible deprotonation event of benzenium ions built in H-ZSM-5 during methanol conversion was observed by experiment and theory as a result of CD3CN dosage, denoting their higher acid reactivity compared to the cyclopentenyl cations, which undergo deprotonation only in presence of pyridine. This study uncovers the inverse relationship between the acid reactivity of carbenium ions of different nature and their stability in the surface-bound state.