Increasing crystallize size or aluminum content in MFI-type zeolites independently enhances the propagation of the aromatics-based methylation/dealkylation cycle relative to that of the olefins-based methylation/cracking cycle in methanol-to-hydrocarbons (MTH) conversion and consequentially results in higher ethene selectivity. Ethene selectivity increases monotonically with increasing aluminum content for HZSM-5 samples with nearly identical crystallite size consequent to an increase in the intracrystalline contact time analogous to our recent report detailing the effects of crystallite size (Khare et al., 2015) on MTH selectivity. The confected effects of crystallite size and site density on MTH selectivity can therefore, be correlated using a descriptor that represents the average number of acid sites that an olefin-precursor will interact with before elution.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Catalysis|
|State||Published - Mar 20 2017|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors acknowledge financial support from National Science Foundation (CBET 1055846) and King Abdullah University of Science and Technology (KAUST), Saudi Arabia. The authors also acknowledge Mr. Brandon Foley, University of Minnesota, and Mr. Sukaran Arora, University of Minnesota, for help with catalyst preparation and the experimental setup.