Isobutane Transformation to Aromatics on Zn‐Modified Zeolites. The Intermediates and the Effect of Zn2+ and ZnO Species on the Reaction Occurrence Revealed with 13C MAS NMR Full article
| Journal |
ChemPhysChem
ISSN: 1439-4235 , E-ISSN: 1439-7641 |
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| Output data | Year: 2022, Volume: 23, Number: 1, Article number : e2021005, Pages count : 9 DOI: 10.1002/cphc.202100587 | ||||
| Tags | 13C MAS NMR; Zn-modified zeolite; 13C-labelled isobutane; mechanism; aromatization | ||||
| Authors |
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| Affiliations |
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Funding (2)
| 1 |
Russian Science Foundation German Research Foundation |
19-43-04101 |
| 2 | German Research Foundation | HA 1893/22-1 |
Abstract:
To clarify the effects of different Zn species, zeolite topology and acidity (quantity of Brønsted acid sites, BAS) on alkane aromatization, isobutane transformation on Zn 2+ /H-ZSM-5, Zn 2+ /H-BEA, and ZnO/H-BEA zeolites has been monitored with 13 C MAS NMR. The alkane transformation has been established to occur by aromatization and hydrogenolysis pathways. Zn 2+ species is more efficient for the aromatization reaction because aromatic products are formed at lower temperatures on Zn 2+ /H-BEA and Zn 2+ /H-ZSM-5 than on ZnO/H-BEA. The larger quantity of BAS in ZnO/H-BEA seems to provide a higher degree of the hydrogenolysis pathway on this catalyst. The mechanism of the alkane aromatization is similar for the zeolites of different topology and containing different Zn species, with the main reaction steps being the following: (i) isobutane dehydrogenation to isobutene via isobutylzinc; (ii) isobutene stabilization as a π-complex on Zn sites; (iii) isobutene oligomerization via the alkene insertion into Zn–C bond of methyl-σ-allylzinc formed from the π-complex; (iv) oligomer dehydrogenation with intermediate formation of polyene carbanionic structures; (v) aromatics formation via further polyene dehydrogenation, protonation, cyclization, deprotonation steps with BAS involvement.
Cite:
Gabrienko A.A.
, Lashchinskaya Z.N.
, Arzumanov S.S.
, Toktarev A.V.
, Freude D.
, Haase J.
, Stepanov A.G.
Isobutane Transformation to Aromatics on Zn‐Modified Zeolites. The Intermediates and the Effect of Zn2+ and ZnO Species on the Reaction Occurrence Revealed with 13C MAS NMR
ChemPhysChem. 2022. V.23. N1. e2021005 :1-9. DOI: 10.1002/cphc.202100587 WOS Scopus РИНЦ ANCAN PMID OpenAlex
Isobutane Transformation to Aromatics on Zn‐Modified Zeolites. The Intermediates and the Effect of Zn2+ and ZnO Species on the Reaction Occurrence Revealed with 13C MAS NMR
ChemPhysChem. 2022. V.23. N1. e2021005 :1-9. DOI: 10.1002/cphc.202100587 WOS Scopus РИНЦ ANCAN PMID OpenAlex
Dates:
| Submitted: | Aug 4, 2021 |
| Accepted: | Sep 6, 2021 |
| Published online: | Sep 9, 2021 |
| Published print: | Jan 5, 2022 |
Identifiers:
| Web of science: | WOS:000700134400001 |
| Scopus: | 2-s2.0-85115690254 |
| Elibrary: | 47104952 |
| Chemical Abstracts: | 2021:2125417 |
| Chemical Abstracts (print): | 178:97063 |
| PMID: | 34505329 |
| OpenAlex: | W3197806230 |