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Remarkably fast oxidation of alkanes by hydrogen peroxide catalyzed by a tetracopper(II) triethanolaminate complex: Promoting effects of acid co-catalysts and water, kinetic and mechanistic featuresстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Kirillova Marina V., Kozlov Yuriy N., Shul’pina Lidia S., Lyakin Oleg Y., Kirillov Alexander M., Talsi Evgenii P., Pombeiro Armando J.L., Shul’pin Georgiy B.
- Журнал: Journal of Catalysis
- Том: 268
- Номер: 1
- Год издания: 2009
- Издательство: Academic Press
- Местоположение издательства: United States
- Первая страница: 26
- Последняя страница: 38
- DOI: 10.1016/j.jcat.2009.08.016
- Аннотация: The kinetic and mechanistic features of alkane oxidations to the corresponding alkyl hydroperoxides (main primary products), alcohols and ketones (secondary products) in the systems composed of tetracopper(II) triethanolaminate catalyst [O⊂Cu4{N(CH2CH2O)3}4(BOH)4][BF4]2 (1), aqueous hydrogen peroxide, acetonitrile solvent and an acid promoter (co-catalyst), have been investigated based on the combination of experimental kinetic, selectivity, ESR and UV–vis methods. The nature of acid promoter (hydrochloric, sulfuric, nitric and trifluoroacetic acid) is shown to be a key factor affecting significantly the rate of alkane oxidation. Although all these acids exhibit noticeable promoting effect, it has been observed that in the presence of HCl the reaction proceeds extremely rapidly, being one order faster than those promoted by the other acids, and allowing to achieve the remarkably high turnover frequencies (TOFs) of ca. 600 h−1. The unusual rate-accelerating role of water has also been disclosed in the oxidation of cyclohexane catalyzed by 1 + HCl or 1 + CF3COOH systems. Furthermore, uncommon second-order reaction kinetics with respect to the catalyst have been found. A mechanism of the alkane oxygenation has been proposed, which includes the formation of hydroxyl radicals attacking the alkane molecule. Hydroxyl radicals are formed via the interaction between H2O2 and catalytically active Cu(I) species, the latter being reversibly generated from 1 under the action of an acid, H2O2 and water.
- Добавил в систему: Астахов Григорий Сергеевич