Selectivity control through fundamental mechanistic insight in the conversion of methanol to hydrocarbons over zeolites

Teketel, Shewangizaw; Olsbye, Unni; Lillerud, Karl Petter; Beato, Pablo; Svelle, Stian

doi:10.1016/j.micromeso.2010.07.013

Cited by 147 publications

(190 citation statements)

References 41 publications

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“…In the one-dimensional pores of H-ZSM-22 only alkenes were found to be active HP species resulting in the production of branched C 5+ alkenes, [72][73][74][75][76][77][78] whereas aromatics were found to be dominating HP species in H-SAPO-34 and large pore zeolites H-beta and H-SSZ-24. 22,24,[79][80][81][82] A high activity of aromatics is mostly coupled with a high selectivity towards ethene and propene.…”

Section: Catalysis Science and Technology Papermentioning

confidence: 99%

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Wispelaere

Bailleul

Speybroeck

2016

Catal. Sci. Technol.

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Title: Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions Advanced ab initio molecular dynamics techniques enable study of the infl uence of catalyst topology and acidity, reaction temperature and the presence of additional guest molecules on methylation reactions of benzene and propene, which are crucial reaction steps in the conversion of methanol into hydrocarbons. Our advanced simulations provide detailed insight into how operating conditions impact the competition of the concerted and stepwise methylation mechanism and thus the reaction kinetics. As featured in:See and mechanism of individual reaction steps at operating conditions. Herein we use state-of-the-art advanced ab initio molecular dynamics techniques to study the influence of catalyst topology and acidity, reaction temperature and the presence of additional guest molecules on elementary reactions. Such advanced modeling techniques provide complementary insight to experimental knowledge as the impact of individual factors on the reaction mechanism and kinetics of zeolite-catalyzed reactions may be unraveled. We study key reaction steps in the conversion of methanol to hydrocarbons, namely benzene and propene methylation. These reactions may occur either in a concerted or stepwise fashion, i.e. methanol directly transfers its methyl group to a hydrocarbon or the reaction goes through a framework-bound methoxide intermediate. The DFT-based dynamical approach enables mimicking reaction conditions as close as possible and studying the competition between two methylation mechanisms in an integrated fashion. The reactions are studied in the unidirectional AFI-structured H-SSZ-24, H-SAPO-5 and TON-structured H-ZSM-22 materials. We show that varying the temperature, topology, acidity and number of protic molecules surrounding the active site may tune the reaction mechanism at the molecular level. Obtaining molecular control is crucial in optimizing current zeolite processes and designing emerging new technologies bearing alternative feedstocks.

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Section: Catalysis Science and Technology Papermentioning

confidence: 99%

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Wispelaere

Bailleul

Speybroeck

2016

Catal. Sci. Technol.

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“…Also, methylation is now known to be a key reaction step in the increasingly important methanol to hydrocarbons (MTH) process, which constitutes the final step in a chain of reactions eventually giving transportation fuels or light alkenes from coal, natural gas, or biomass [4]. Methylation of the reactive alkene or aromatic intermediates has been shown to be an integral part of the MTH reaction mechanism [5][6][7]. Moreover, it has also been shown that methylation of alkenes is of importance in a newer process where dimethyl ether (DME) in converted into highly branched alkanes at lower temperature and higher pressure that regular MTH conditions [8].…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Aspects of the Zeolite Catalyzed Methylation of Alkenes and Aromatics with Methanol: A Review

et al. 2011

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Alkylation and methylation are important reactions in industrial zeolite catalyzed hydrocarbon transformation processes. This contribution compiles the present knowledge concerning the reaction mechanism of zeolite catalyzed methylation of alkenes and aromatics, based on insights obtained using spectroscopy, quantum chemistry, and kinetic measurements. A central issue is to discuss the potential role surface bound methoxy group intermediates.

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“…Further study on the MTO reaction over H-ZSM-22 is necessary, especially on the reaction mechanism. Just before the submission of our manuscript, a paper focused on the reaction mechanism over H-ZSM-22 has been published by Olsbye and co-workers [28].…”

Section: Introductionmentioning

confidence: 99%

Comparative study of MTO conversion over SAPO-34, H-ZSM-5 and H-ZSM-22: Correlating catalytic performance and reaction mechanism to zeolite topology

et al. 2011

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Selectivity control through fundamental mechanistic insight in the conversion of methanol to hydrocarbons over zeolites

Cited by 147 publications

References 41 publications

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Towards molecular control of elementary reactions in zeolite catalysis by advanced molecular simulations mimicking operating conditions

Mechanistic Aspects of the Zeolite Catalyzed Methylation of Alkenes and Aromatics with Methanol: A Review

Comparative study of MTO conversion over SAPO-34, H-ZSM-5 and H-ZSM-22: Correlating catalytic performance and reaction mechanism to zeolite topology

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