Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13
Hybrid density functional theory calculations are used to investigate different mechanisms of the isomerization of n-butane to isobutane via intermediate formation of olefins. The monomolecular mechanism for isomerization of butene and isobutene is found to be prevalent, with a Gibbs free energy bar...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-07-01
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| Series: | Frontiers in Catalysis |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fctls.2023.1213803/full |
| _version_ | 1797786657294909440 |
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| author | Lucas Spiske Philipp N. Plessow Kamila Kazmierczak Bart D. Vandegehuchte Felix Studt |
| author_facet | Lucas Spiske Philipp N. Plessow Kamila Kazmierczak Bart D. Vandegehuchte Felix Studt |
| author_sort | Lucas Spiske |
| collection | DOAJ |
| description | Hybrid density functional theory calculations are used to investigate different mechanisms of the isomerization of n-butane to isobutane via intermediate formation of olefins. The monomolecular mechanism for isomerization of butene and isobutene is found to be prevalent, with a Gibbs free energy barrier of 155 kJ/mol at 400°C, compared to the bimolecular mechanism (190 kJ/mol) due to less favorable entropy for the latter. Hydrogen transfer reactions that convert olefins into alkanes (and vice versa) are also included in the investigations, and show a free energy barrier of 203 kJ/mol for conversion of isobutene to isobutane. Additionally, a methyl transfer mechanism is discussed as a possible pathway for formation of C3 and C5 side products, in comparison to the bimolecular mechanism; the highest barrier of the initial methyl transfer is calculated to be 227 kJ/mol. We discuss the influence of entropy and anharmonicity on all mechanisms, stating that through the uncertainties in computational methods when calculating these systems, the calculated reaction barriers are likely to be overestimated here. |
| first_indexed | 2024-03-13T01:10:57Z |
| format | Article |
| id | doaj.art-b0c3a749dee34d5b9bde8fd2c4795baf |
| institution | Directory Open Access Journal |
| issn | 2673-7841 |
| language | English |
| last_indexed | 2024-03-13T01:10:57Z |
| publishDate | 2023-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Catalysis |
| spelling | doaj.art-b0c3a749dee34d5b9bde8fd2c4795baf2023-07-05T22:39:53ZengFrontiers Media S.A.Frontiers in Catalysis2673-78412023-07-01310.3389/fctls.2023.12138031213803Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13Lucas Spiske0Philipp N. Plessow1Kamila Kazmierczak2Bart D. Vandegehuchte3Felix Studt4Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Karlsruhe, GermanyInstitute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Karlsruhe, GermanyTotalEnergies OneTech Belgium, Feluy, BelgiumTotalEnergies OneTech Belgium, Feluy, BelgiumInstitute of Catalysis Research and Technology, Karlsruhe Institute of Technology, Karlsruhe, GermanyHybrid density functional theory calculations are used to investigate different mechanisms of the isomerization of n-butane to isobutane via intermediate formation of olefins. The monomolecular mechanism for isomerization of butene and isobutene is found to be prevalent, with a Gibbs free energy barrier of 155 kJ/mol at 400°C, compared to the bimolecular mechanism (190 kJ/mol) due to less favorable entropy for the latter. Hydrogen transfer reactions that convert olefins into alkanes (and vice versa) are also included in the investigations, and show a free energy barrier of 203 kJ/mol for conversion of isobutene to isobutane. Additionally, a methyl transfer mechanism is discussed as a possible pathway for formation of C3 and C5 side products, in comparison to the bimolecular mechanism; the highest barrier of the initial methyl transfer is calculated to be 227 kJ/mol. We discuss the influence of entropy and anharmonicity on all mechanisms, stating that through the uncertainties in computational methods when calculating these systems, the calculated reaction barriers are likely to be overestimated here.https://www.frontiersin.org/articles/10.3389/fctls.2023.1213803/fullzeolitesisomerizationchabaziteH-SSZ-13DFTab initio |
| spellingShingle | Lucas Spiske Philipp N. Plessow Kamila Kazmierczak Bart D. Vandegehuchte Felix Studt Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13 Frontiers in Catalysis zeolites isomerization chabazite H-SSZ-13 DFT ab initio |
| title | Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13 |
| title_full | Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13 |
| title_fullStr | Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13 |
| title_full_unstemmed | Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13 |
| title_short | Theoretical investigation of catalytic n-butane isomerization over H-SSZ-13 |
| title_sort | theoretical investigation of catalytic n butane isomerization over h ssz 13 |
| topic | zeolites isomerization chabazite H-SSZ-13 DFT ab initio |
| url | https://www.frontiersin.org/articles/10.3389/fctls.2023.1213803/full |
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