Herold, Felix ; Oefner, Niklas ; Zakgeym, Dina ; Drochner, Alfons ; Qi, Wei ; Etzold, Bastian J. M. (2022)
The High‐Temperature Acidity Paradox of Oxidized Carbon: An in situ DRIFTS Study.
In: ChemCatChem, 14 (4)
doi: 10.1002/cctc.202101586
Artikel, Bibliographie
Dies ist die neueste Version dieses Eintrags.
Kurzbeschreibung (Abstract)
Until now, oxygen functionalized carbon materials were not considered to exhibit significant acidity at high temperatures, since carboxylic acids, the most prominent acidic functionality, are prone to decarboxylation at temperatures exceeding 250 °C. Paradoxically, we could show that oxidized carbon materials can act as highly active high‐temperature solid acid catalysts in the dehydration of methanol at 300 °C, showing an attractive selectivity to dimethyl ether (DME) of up to 92 % at a conversion of 47 %. Building on a tailor‐made carbon model material, we developed a strategy to utilize in situ DRIFT spectroscopy for the analysis of carbon surface species under process conditions, which until now proofed to be highly challenging due to the high intrinsic absorbance of carbon. By correlating the catalytic behavior with a comprehensive in situ DRIFTS study and extensive post mortem analysis we could attribute the high‐temperature acidity of oxidized carbons to the interaction of thermally stable carboxylic anhydrides and lactones with nucleophilic constituents of the reaction atmosphere e. g. methanol and H₂O. Dynamic equilibria of surface oxides depending on reaction atmosphere and temperature were observed, and a methyl ester, formed by methanolysis of anhydrides and lactones, was identified as key intermediate for DME generation on oxidized carbon catalysts.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2022 |
| Autor(en): | Herold, Felix ; Oefner, Niklas ; Zakgeym, Dina ; Drochner, Alfons ; Qi, Wei ; Etzold, Bastian J. M. |
| Art des Eintrags: | Bibliographie |
| Titel: | The High‐Temperature Acidity Paradox of Oxidized Carbon: An in situ DRIFTS Study |
| Sprache: | Englisch |
| Publikationsjahr: | 2022 |
| Ort: | Darmstadt |
| Verlag: | Wiley-VCH |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | ChemCatChem |
| Jahrgang/Volume einer Zeitschrift: | 14 |
| (Heft-)Nummer: | 4 |
| Kollation: | 12 Seiten |
| DOI: | 10.1002/cctc.202101586 |
| Zugehörige Links: | |
| Kurzbeschreibung (Abstract): | Until now, oxygen functionalized carbon materials were not considered to exhibit significant acidity at high temperatures, since carboxylic acids, the most prominent acidic functionality, are prone to decarboxylation at temperatures exceeding 250 °C. Paradoxically, we could show that oxidized carbon materials can act as highly active high‐temperature solid acid catalysts in the dehydration of methanol at 300 °C, showing an attractive selectivity to dimethyl ether (DME) of up to 92 % at a conversion of 47 %. Building on a tailor‐made carbon model material, we developed a strategy to utilize in situ DRIFT spectroscopy for the analysis of carbon surface species under process conditions, which until now proofed to be highly challenging due to the high intrinsic absorbance of carbon. By correlating the catalytic behavior with a comprehensive in situ DRIFTS study and extensive post mortem analysis we could attribute the high‐temperature acidity of oxidized carbons to the interaction of thermally stable carboxylic anhydrides and lactones with nucleophilic constituents of the reaction atmosphere e. g. methanol and H₂O. Dynamic equilibria of surface oxides depending on reaction atmosphere and temperature were observed, and a methyl ester, formed by methanolysis of anhydrides and lactones, was identified as key intermediate for DME generation on oxidized carbon catalysts. |
| Freie Schlagworte: | acid/base catalysis, carbon materials, carbon surface chemistry, heterogeneous catalysis, in situ spectroscopy |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Fachbereich(e)/-gebiet(e): | 07 Fachbereich Chemie 07 Fachbereich Chemie > Ernst-Berl-Institut 07 Fachbereich Chemie > Ernst-Berl-Institut > Fachgebiet Technische Chemie |
| Hinterlegungsdatum: | 02 Aug 2024 12:42 |
| Letzte Änderung: | 02 Aug 2024 12:42 |
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The High‐Temperature Acidity Paradox of Oxidized Carbon: An in situ DRIFTS Study. (deposited 01 Jul 2022 11:56)
- The High‐Temperature Acidity Paradox of Oxidized Carbon: An in situ DRIFTS Study. (deposited 02 Aug 2024 12:42) [Gegenwärtig angezeigt]
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