Conversion of methanol over H-ZSM-22: The reaction mechanism and deactivation

Li, Jinzhe; Wei, Yingxu; Qi, Yue; Tian, Peng; Li, Bing; He, Yanli; Chang, Fuxiang; Sun, Xinde; Liu, Zhongmin

doi:10.1016/j.cattod.2010.10.095

Cited by 58 publications

(63 citation statements)

References 29 publications

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“…Chemie the steric properties of the catalyst topology it was possible to suppress product formation by the aromatics-based cycle whilst leaving the C 3+ alkene-based cycle operative. [107] These experiments pertaining to the MTH mechanism over H-ZSM-22 were later reproduced by Li et al [110,111] We are now at a position where we can rationalize many of the features observed in the product spectrum of different MTH catalysts. Figure 15 shows chromatogram traces of the products detected in the effluent during the MTH reaction at 400 8C over four catalysts having different topologies.…”

Section: Methodsmentioning

confidence: 69%

Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity

et al. 2012

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Liquid hydrocarbon fuels play an essential part in the global energy chain, owing to their high energy density and easy transportability. Olefins play a similar role in the production of consumer goods. In a post-oil society, fuel and olefin production will rely on alternative carbon sources, such as biomass, coal, natural gas, and CO(2). The methanol-to-hydrocarbons (MTH) process is a key step in such routes, and can be tuned into production of gasoline-rich (methanol to gasoline; MTG) or olefin-rich (methanol to olefins; MTO) product mixtures by proper choice of catalyst and reaction conditions. This Review presents several commercial MTH projects that have recently been realized, and also fundamental research into the synthesis of microporous materials for the targeted variation of selectivity and lifetime of the catalysts.

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Section: Methodsmentioning

confidence: 69%

Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity

et al. 2012

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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%

“…Several experimental studies clearly pointed out that methanol conversion in H-ZSM-22 occurs through the alkene cycle and that aromatic HP species are not active. [73][74][75]77,78,125 Cui et al…”

Section: Concertedmentioning

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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“…[103] Schließlich wurde vorgeschlagen, dass während der MTH-Reaktion an H-ZSM-5 zwei mechanistische Zyklen simultan ablaufen: ein Aromatenzyklus, in dem Ethen (und Propen) [104] aus niederen Methylbenzolen gebildet wird (welche durch Methylierungen regeneriert werden), und ein Methylierungs-/ Spaltzyklus, wder nur C 3+ -Alkene (und kein Ethen) enthält. [110,111] Wir sind jetzt an einem Punkt angelangt, an dem wir viele der beobachteten Funktionen im Produktspektrum verschiedener MTH-Katalysatoren erklären kçnnen. [101,102,105] Es stellt eine Verfeinerung des ursprünglichen Kohlenwasserstoffpool.Mechanismus dar, wie er von Dahl und Kolboe vorgeschlagen wurde.…”

Section: Methanol-reformierungunclassified

“…[107] Diese Experimente in Bezug auf den MTH-Mechanismus an H-ZSM-22 wurden später von Li et al reproduziert. [110,111] Wir sind jetzt an einem Punkt angelangt, an dem wir viele der beobachteten Funktionen im Produktspektrum verschiedener MTH-Katalysatoren erklären kçnnen. Abbildung 15 zeigt die Chromatogramme der Gasphasenprodukte von vier Katalysatoren unterschiedlicher Topologie während der MTH-Reaktion bei 400 8C.…”

Section: Methanol-reformierungunclassified

Umwandlung von Methanol in Kohlenwasserstoffe: Wie Zeolith‐Hohlräume und Porengröße die Produktselektivität bestimmen

et al. 2012

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Flüssige Kohlenwasserstoffe nehmen aufgrund ihrer hohen Energiedichte und guten Transportfähigkeit eine Schlüsselrolle in der globalen Energieversorgung ein. Eine vergleichbare Bedeutung haben niedere Alkene wie Ethylen und Propylen in der Produktion von Verbrauchsgütern. In einer Gesellschaft der Nach‐Erdöl‐Zeit wird die Produktion von Kraftstoffen und Alkenen auf alternative Quellen wie Biomasse, Kohle, Erdgas und CO2 angewiesen sein. Die Umwandlung von Methanol in Kohlenwasserstoffe, bekannt als Methanol‐to‐ Hydrocarbons(MTH)‐Reaktion, könnte eine zentrale Rolle auf diesem Weg einnehmen, weil je nach Wahl des Katalysators und der Reaktionsbedingungen gezielt Benzin (Methanol‐to‐Gasoline, MTG) oder Alkene (Methanol‐to‐Olefins, MTO) hergestellt werden können. Dieser Aufsatz beschreibt eine Reihe von industriellen MTH‐Projekten, die in den letzten Jahren realisiert wurden, sowie den aktuellen Stand der Grundlagenforschung zur Synthese und Anwendung von mikroporösen Materialien für die gezielte Veränderung von Selektivität und Lebensdauer der Katalysatoren.

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Conversion of methanol over H-ZSM-22: The reaction mechanism and deactivation

Cited by 58 publications

References 29 publications

Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity

Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity

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

Umwandlung von Methanol in Kohlenwasserstoffe: Wie Zeolith‐Hohlräume und Porengröße die Produktselektivität bestimmen

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