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On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction

The influence of framework substituents (Al(3+), Ga(3+), Fe(3+) and B(3+)) and morphology (bulk vs. nanometer‐sized sheets) of MFI zeolites on the acidity and catalytic performance in the methanol‐to‐hydrocarbons (MTH) reaction was investigated. The Brønsted acid density and strength decreased in th...

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Autores principales: Meng, Lingqian, Zhu, Xiaochun, Mezari, Brahim, Pestman, Robert, Wannapakdee, Wannaruedee, Hensen, Emiel J. M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5698753/
https://www.ncbi.nlm.nih.gov/pubmed/29201243
http://dx.doi.org/10.1002/cctc.201700916
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author Meng, Lingqian
Zhu, Xiaochun
Mezari, Brahim
Pestman, Robert
Wannapakdee, Wannaruedee
Hensen, Emiel J. M.
author_facet Meng, Lingqian
Zhu, Xiaochun
Mezari, Brahim
Pestman, Robert
Wannapakdee, Wannaruedee
Hensen, Emiel J. M.
author_sort Meng, Lingqian
collection PubMed
description The influence of framework substituents (Al(3+), Ga(3+), Fe(3+) and B(3+)) and morphology (bulk vs. nanometer‐sized sheets) of MFI zeolites on the acidity and catalytic performance in the methanol‐to‐hydrocarbons (MTH) reaction was investigated. The Brønsted acid density and strength decreased in the order Al(OH)Si>Ga(OH)Si>Fe(OH)Si≫B(OH)Si. Pyridine (15)N NMR spectra confirmed the differences in the Brønsted and Lewis acid strengths but also provided evidence for site heterogeneity in the Brønsted acid sites. Owing to the lower efficiency with which tervalent ions can be inserted into the zeolite framework, sheet‐like zeolites exhibited lower acidity than bulk zeolites. The sheet‐like Al‐containing MFI zeolite exhibited the greatest longevity as a MTH catalyst, outperforming its bulk [Al]MFI counterpart. Although the lower acidity of bulk [Ga]MFI led to a better catalytic performance than bulk [Al]MFI, the sheet‐like [Ga]MFI sample was found to be nearly inactive owing to lower and heterogeneous Brønsted acidity. All Fe‐ and B‐substituted zeolite samples displayed very low catalytic performance owing to their weak acidity. Based on the product distribution, the MTH reaction was found to be dominated by the olefins‐based catalytic cycle. The small contribution of the aromatics‐based catalytic cycle was larger for bulk zeolite than for sheet‐like zeolite, indicating that shorter residence time of aromatics can explain the lower tendency toward coking and enhanced catalyst longevity.
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spelling pubmed-56987532017-11-30 On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction Meng, Lingqian Zhu, Xiaochun Mezari, Brahim Pestman, Robert Wannapakdee, Wannaruedee Hensen, Emiel J. M. ChemCatChem Full Papers The influence of framework substituents (Al(3+), Ga(3+), Fe(3+) and B(3+)) and morphology (bulk vs. nanometer‐sized sheets) of MFI zeolites on the acidity and catalytic performance in the methanol‐to‐hydrocarbons (MTH) reaction was investigated. The Brønsted acid density and strength decreased in the order Al(OH)Si>Ga(OH)Si>Fe(OH)Si≫B(OH)Si. Pyridine (15)N NMR spectra confirmed the differences in the Brønsted and Lewis acid strengths but also provided evidence for site heterogeneity in the Brønsted acid sites. Owing to the lower efficiency with which tervalent ions can be inserted into the zeolite framework, sheet‐like zeolites exhibited lower acidity than bulk zeolites. The sheet‐like Al‐containing MFI zeolite exhibited the greatest longevity as a MTH catalyst, outperforming its bulk [Al]MFI counterpart. Although the lower acidity of bulk [Ga]MFI led to a better catalytic performance than bulk [Al]MFI, the sheet‐like [Ga]MFI sample was found to be nearly inactive owing to lower and heterogeneous Brønsted acidity. All Fe‐ and B‐substituted zeolite samples displayed very low catalytic performance owing to their weak acidity. Based on the product distribution, the MTH reaction was found to be dominated by the olefins‐based catalytic cycle. The small contribution of the aromatics‐based catalytic cycle was larger for bulk zeolite than for sheet‐like zeolite, indicating that shorter residence time of aromatics can explain the lower tendency toward coking and enhanced catalyst longevity. John Wiley and Sons Inc. 2017-09-14 2017-10-23 /pmc/articles/PMC5698753/ /pubmed/29201243 http://dx.doi.org/10.1002/cctc.201700916 Text en © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs (http://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
spellingShingle Full Papers
Meng, Lingqian
Zhu, Xiaochun
Mezari, Brahim
Pestman, Robert
Wannapakdee, Wannaruedee
Hensen, Emiel J. M.
On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction
title On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction
title_full On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction
title_fullStr On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction
title_full_unstemmed On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction
title_short On the Role of Acidity in Bulk and Nanosheet [T]MFI (T=Al(3+) (,) Ga(3+), Fe(3+), B(3+)) Zeolites in the Methanol‐to‐Hydrocarbons Reaction
title_sort on the role of acidity in bulk and nanosheet [t]mfi (t=al(3+) (,) ga(3+), fe(3+), b(3+)) zeolites in the methanol‐to‐hydrocarbons reaction
topic Full Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5698753/
https://www.ncbi.nlm.nih.gov/pubmed/29201243
http://dx.doi.org/10.1002/cctc.201700916
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