Insight into the Effect of Water on the Methanol-to-Olefins Conversion in H-SAPO-34 from Molecular Simulations and in Situ Microspectroscopy
| Autor: | De Wispelaere, Kristof, Wondergem, Caterina S., Ensing, Bernd, Hemelsoet, Karen, Meijer, Evert Jan, Weckhuysen, Bert M., Van Speybroeck, Veronique, Ruiz Martinez, Javier, Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis |
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| Přispěvatelé: | Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis, Molecular Simulations (HIMS, FNWI) |
| Rok vydání: | 2016 |
| Předmět: |
UV-vis spectroscopy
REACTION-MECHANISM In situ Induction period water Inorganic chemistry zeolites HYDROCARBON FORMATION Methoxide 010402 general chemistry Photochemistry NITRILE ADSORPTION 01 natural sciences Homogeneous distribution metadynamics UV/VIS MICROSPECTROSCOPY Catalysis MICROPOROUS MATERIALS Propene chemistry.chemical_compound confocal fluorescence microscopy Reactivity (chemistry) ACIDIC ZEOLITE CATALYSTS PRODUCT SELECTIVITY 010405 organic chemistry General Chemistry molecular dynamics 0104 chemical sciences Chemistry methanol-to-olefins chemistry THEORETICAL SIMULATIONS Methanol COKE FORMATION MTO REACTION |
| Zdroj: | ACS CATALYSIS ACS Catalysis, 6(3), 1991. American Chemical Society ACS Catalysis, 6(3), 1991-2002. American Chemical Society |
| ISSN: | 2155-5435 |
| DOI: | 10.1021/acscatal.5b02139 |
| Popis: | The role of water in the methanol-to-olefins (MTO) process over H-SAPO-34 has been elucidated by a combined theoretical and experimental approach, encompassing advanced molecular dynamics simulations and in situ microspectroscopy. First-principles calculations at the molecular level point out that water competes with methanol and propene for direct access to the Bronsted acid sites. This results in less efficient activation of these molecules, which are crucial for the formation of the hydrocarbon pool. Furthermore, lower intrinsic methanol reactivity toward methoxide formation has been observed. These observations are in line with a longer induction period observed from in situ UV-vis microspectroscopy experiments. These experiments revealed a slower and more homogeneous discoloration of H-SAPO-34, while in situ confocal fluorescence microscopy confirmed the more homogeneous distribution and larger amount of MTO intermediates when cofeeding water. As such, it is shown that water induces a more efficient use of the H-SAPO-34 catalyst crystals at the microscopic level. The combined experimental-theoretical approach gives a profound insight into the role of water in the catalytic process at the molecular and single-particle level. © 2016 American Chemical Society. |
| Databáze: | OpenAIRE |
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