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Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts
The choice of TiO(2) crystal phase (i. e., anatase, rutile, or brookite) greatly influences catalyst performance in the gas‐phase ketonization of small volatile fatty acids, such as acetic acid and propionic acid. Rutile TiO(2) was found to perform best, combining superior activity, as exemplified b...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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John Wiley and Sons Inc.
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8361664/ https://www.ncbi.nlm.nih.gov/pubmed/33961345 http://dx.doi.org/10.1002/cssc.202100721 |
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author | Fufachev, Egor V. Weckhuysen, Bert M. Bruijnincx, Pieter C. A. |
author_facet | Fufachev, Egor V. Weckhuysen, Bert M. Bruijnincx, Pieter C. A. |
author_sort | Fufachev, Egor V. |
collection | PubMed |
description | The choice of TiO(2) crystal phase (i. e., anatase, rutile, or brookite) greatly influences catalyst performance in the gas‐phase ketonization of small volatile fatty acids, such as acetic acid and propionic acid. Rutile TiO(2) was found to perform best, combining superior activity, as exemplified by an exceptional reaction rate of 141.8 mmol h(−1) g(cat) (−1) (at 425 °C and 24 h(−1)) with excellent ketone selectivity when propionic acid was used. Brookite, to the best of our knowledge never reported before as a viable ketonization catalyst, was found to outperform the well‐studied anatase phase, but not rutile. Operando Fourier‐transform IR spectroscopy measurements combined with on‐line mass spectrometry showed that bidentate carboxylates were the most abundant surface species on the rutile and brookite surfaces, while on anatase both monodentate and bidentate carboxylates co‐existed. The bidendate carboxylates were thought to be precursors to the active ketonization species, likely monodentate intermediates more prone to C−C coupling. Ketonization activity did not directly correlate with acidity; the observed, strong crystal phase effect did suggest that ketonization activity is influenced strongly by geometrical factors that determine the ease of formation of the relevant surface intermediates. |
format | Online Article Text |
id | pubmed-8361664 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-83616642021-08-17 Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts Fufachev, Egor V. Weckhuysen, Bert M. Bruijnincx, Pieter C. A. ChemSusChem Full Papers The choice of TiO(2) crystal phase (i. e., anatase, rutile, or brookite) greatly influences catalyst performance in the gas‐phase ketonization of small volatile fatty acids, such as acetic acid and propionic acid. Rutile TiO(2) was found to perform best, combining superior activity, as exemplified by an exceptional reaction rate of 141.8 mmol h(−1) g(cat) (−1) (at 425 °C and 24 h(−1)) with excellent ketone selectivity when propionic acid was used. Brookite, to the best of our knowledge never reported before as a viable ketonization catalyst, was found to outperform the well‐studied anatase phase, but not rutile. Operando Fourier‐transform IR spectroscopy measurements combined with on‐line mass spectrometry showed that bidentate carboxylates were the most abundant surface species on the rutile and brookite surfaces, while on anatase both monodentate and bidentate carboxylates co‐existed. The bidendate carboxylates were thought to be precursors to the active ketonization species, likely monodentate intermediates more prone to C−C coupling. Ketonization activity did not directly correlate with acidity; the observed, strong crystal phase effect did suggest that ketonization activity is influenced strongly by geometrical factors that determine the ease of formation of the relevant surface intermediates. John Wiley and Sons Inc. 2021-05-28 2021-07-06 /pmc/articles/PMC8361664/ /pubmed/33961345 http://dx.doi.org/10.1002/cssc.202100721 Text en © 2021 The Authors. ChemSusChem published by Wiley-VCH GmbH https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. |
spellingShingle | Full Papers Fufachev, Egor V. Weckhuysen, Bert M. Bruijnincx, Pieter C. A. Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts |
title | Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts |
title_full | Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts |
title_fullStr | Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts |
title_full_unstemmed | Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts |
title_short | Crystal Phase Effects on the Gas‐Phase Ketonization of Small Carboxylic Acids over TiO(2) Catalysts |
title_sort | crystal phase effects on the gas‐phase ketonization of small carboxylic acids over tio(2) catalysts |
topic | Full Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8361664/ https://www.ncbi.nlm.nih.gov/pubmed/33961345 http://dx.doi.org/10.1002/cssc.202100721 |
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