The Limits of the Confinement Effect Associated to Cage Topology on the Control of the MTO Selectivity

The light olefin product distribution of the methanol‐to‐olefin (MTO) reaction catalyzed by acid zeolites and zeotypes depends on the nature of the entrapped hydrocarbon pool species that act as co‐catalysts. The preferential stabilization by confinement effects of the cationic intermediates involved in the side‐chain or paring pathways of the aromatics‐based cycle of the MTO mechanism in small‐pore cage‐based zeolites is determined by the topology of the cavity, and can be quantitatively described through the Eint(7/5) parameter obtained from DFT calculations. In this work we extend the study of the Eint(7/5) parameter to a wide range of structures (ERI, LEV, AEI, CHA, DDR, AFX, RTH, ITE, SAV, UFI, RHO, KFI, and LTA) and discuss its applicability in small cages with steric constraints to host bulky intermediates, in zeolites with a tight fitting between the cavity and the hosted cations, and in large cages where confinement effects are lost in part and competitive processes occur. Confinement effects in small‐pore cage‐based zeolites: The limits of the confinement effect associated to cage topology to control de MTO product distribution in small‐pore cage‐based zeolites is explored for a series of zeolite and zeotype structures containing small cages where steric constraints might change the mechanism, and large cavities where confinement effects are partly lost.