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The concept of quasimolecular electrophilic oxygen in ethylene epoxidation over silverстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Boronin A.I., Avdeev V.I., Koshcheev S.V., Murzakhmetov K.T., Ruzankin S.F., Zhidomirov G.M.
- Журнал: Kinetics and Catalysis
- Том: 40
- Номер: 5
- Год издания: 1999
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 653
- Последняя страница: 672
- Аннотация: The ethylene-epoxidizing form of oxygen (O ep) adsorbed on Ag(111) and Ag(110) single crystals and polycrystalline silver foil was examined by X-ray and UV photoelectron spectroscopy (XPS and UPS). It was shown that O ep has a quasimolecular nature and exhibits high thermal stability (T > 700 K). The quantum-chemical study of associative forms of oxygen on the defects of the silver surface was carried out by the methods of density functional theory (DFT) in a cluster approximation. It was found that the associative (molecular) ozone-like species of oxygen on the surface of silver with cationic vacancies (V) is more stable than atomic oxygen (the energy difference is 44 kcal/mol). The identification of emission bands in UV photoelectron spectra performed on the basis of theoretical calculations of the ozone-like structure supported the quasimolecular nature of O ep. The mechanisms known for ethylene epoxidation were analyzed. A new mechanism implying the participation of quasimolecular electrophilic oxygen O ep in epoxidation was proposed. This mechanism describes the major regularities of epoxidation observed in the experiments on a regular basis.
- Добавил в систему: Жидомиров Георгий Михайлович