| Abstract
| - Methanol conversion over H-beta and H-ZSM-5 zeolite catalysts is compared at identical reaction conditions(temperature = 350 °C, WHSV = 7.0 gg-1 h-1), and it is found that H-ZSM-5 yields seven times moreethene relative to propene than H-beta yields. By switching from a 12C methanol feed to 13C methanol, thetransient incorporation of 13C atoms from methanol into the gas-phase products and reaction intermediateslocated within the zeolite voids is followed. For H-beta, penta- and hexamethylbenzene are involved in ahydrocarbon-pool-type mechanism, leading predominantly to propene and the higher alkenes, whereas forH-ZSM-5, the lower methylbenzenes are the intermediates and represent the only route for ethene formation.This work outlines how the zeolite topology determines the type of intermediate participating in the catalyticcycle, thereby controlling the ethene/propene product selectivity in the methanol to olefins reaction.
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