Competitive Pathways of Methane Activation on Zn2+-Modified ZSM-5 Zeolite: H/D Hydrogen Exchange with Brønsted Acid Sites: Versus Dissociative Adsorption to Form Zn-Methyl Species Научная публикация
Журнал |
Catalysis Science and Technology
ISSN: 2044-4753 , E-ISSN: 2044-4761 |
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Вых. Данные | Год: 2016, Том: 6, Номер: 16, Страницы: 6381-6388 Страниц : 8 DOI: 10.1039/c6cy00878j | ||||||
Ключевые слова | Activation analysis; Chemical activation; Dissociation; Hydrogen; Methane; Nuclear magnetic resonance spectroscopy; Paraffins; Positive ions; Reaction intermediates; Zeolites | ||||||
Авторы |
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Организации |
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Информация о финансировании (3)
1 | Федеральное агентство научных организаций России | V.44.2.11. |
2 | Российский фонд фундаментальных исследований | 14-03-00040 |
3 | German Research Foundation | HA 1893/16 |
Реферат:
To clarify the pathways of methane activation on Zn-modified high-silica zeolites, the kinetics of both dissociative adsorption of the alkane C-H bond to form Zn-methyl species and H/D hydrogen exchange between the alkane and Brønsted acid sites (BAS) have been analyzed for Zn2+/H-ZSM-5 containing exclusively Zn2+ cations (no ZnO species in the zeolite) and BAS. Analysis of the kinetics was performed by 1H MAS NMR spectroscopy in situ at 410-540 K. In spite of the activation barrier for H/D hydrogen exchange (68 kJ mol-1) being larger than that for Zn-methyl formation (46 kJ mol-1), the rate of H/D hydrogen exchange has been found to be one order of magnitude higher than the rate of the formation of Zn-methyl species within the studied temperature range. This implies that Zn-methyl species cannot be involved in the reaction of H/D hydrogen exchange as the intermediate responsible for facilitation of this reaction due to the presence of Zn2+ cations in the zeolite (J. Catal., 2008, 253, 11). A new mechanism has been suggested for C-H bond activation in methane on the zeolite modified with Zn2+ cations. It includes first the formation of a transient molecular complex of methane with Zn2+ cations. The complex either is further involved in the reaction of H/D hydrogen exchange or evolves toward the formation of Zn-methyl species and BAS.
Библиографическая ссылка:
Arzumanov S.S.
, Gabrienko A.A.
, Freude D.
, Stepanov A.G.
Competitive Pathways of Methane Activation on Zn2+-Modified ZSM-5 Zeolite: H/D Hydrogen Exchange with Brønsted Acid Sites: Versus Dissociative Adsorption to Form Zn-Methyl Species
Catalysis Science and Technology. 2016. V.6. N16. P.6381-6388. DOI: 10.1039/c6cy00878j WOS Scopus РИНЦ CAPlusCA OpenAlex
Competitive Pathways of Methane Activation on Zn2+-Modified ZSM-5 Zeolite: H/D Hydrogen Exchange with Brønsted Acid Sites: Versus Dissociative Adsorption to Form Zn-Methyl Species
Catalysis Science and Technology. 2016. V.6. N16. P.6381-6388. DOI: 10.1039/c6cy00878j WOS Scopus РИНЦ CAPlusCA OpenAlex
Даты:
Поступила в редакцию: | 21 апр. 2016 г. |
Принята к публикации: | 31 мая 2016 г. |
Опубликована online: | 31 мая 2016 г. |
Идентификаторы БД:
Web of science: | WOS:000381439400023 |
Scopus: | 2-s2.0-84981313520 |
РИНЦ: | 27135173 |
Chemical Abstracts: | 2016:882866 |
Chemical Abstracts (print): | 165:214159 |
OpenAlex: | W2414826031 |