Reactivity of phenoxy radicals. Factors determining the activity of oxygen-centered radicals in reactions with C-H and O-H bonds Научная публикация
| Журнал |
Kinetics and Catalysis
ISSN: 0023-1584 , E-ISSN: 1608-3210 |
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| Вых. Данные | Год: 1997, Том: 38, Номер: 1, Страницы: 35-43 Страниц : 9 | ||
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Реферат:
The experimental rate constants for reactions of phenoxy radicals with hydrocarbons, hydroperoxides, phenols, and aromatic amines are analyzed in terms of the parabolic model of the transition state. The parameters characterizing each reaction series are calculated. The reactivities of the phenoxy (Ar1O.) and sterically hindered phenoxy (Ar2O.) radicals are compared with those of other free radicals bearing a free valence on the oxygen atom. It is shown that under thermoneutral conditions when the reaction enthalpy is equal to zero, all reactions with a reaction center O...H...O are characterized by a low activation energy E(e0) = 43 +/- 2 kJ/mol. Hydrogen atom abstraction from the aliphatic C-H bond proceeds with a higher activation energy (from 55 to 63 kJ/mol) due to triplet repulsion in the transition state. The presence of re-bonds adjacent to the reaction center leads to a rise in E(e0): the presence of a double bond increases E(e0) by 13.4 +/- 3.0 kJ/mol, while the introduction of the aromatic ring increases E(e0) by 8.0 +/- 2.4 kJ/mol in the reactions of RH with RO(.), RO(2)(.), Ar1O., Ar2O., and nitroxyl radicals. Tertiary alkyl substituents in the ortho-position with respect to the phenoxy group cause an increase in E(eO) of 10.2 kJ/mol in the reactions with the O-H bond and of 28.6 kJ/mol in the reactions with C-H bonds. The obtained parameters enable the calculation of the activation energy for any reaction of phenoxy radicals with hydrocarbons, phenols, and hydroperoxides.
Библиографическая ссылка:
Denisov E.T.
, Drozdova T.I.
Reactivity of phenoxy radicals. Factors determining the activity of oxygen-centered radicals in reactions with C-H and O-H bonds
Kinetics and Catalysis. 1997. V.38. N1. P.35-43. WOS Scopus РИНЦ CAPlus OpenAlex
Reactivity of phenoxy radicals. Factors determining the activity of oxygen-centered radicals in reactions with C-H and O-H bonds
Kinetics and Catalysis. 1997. V.38. N1. P.35-43. WOS Scopus РИНЦ CAPlus OpenAlex
Оригинальная версия:
Денисов Е.Т.
, Дроздова Т.И.
Реакционная способность феноксильных радикалов. Факторы, определяющие активность кислородцентрированных радикалов в реакциях со связями С-Н и О-Н
Кинетика и катализ. 1997. Т.38. №1. С.43-51. РЖ ВИНИТИ
Реакционная способность феноксильных радикалов. Факторы, определяющие активность кислородцентрированных радикалов в реакциях со связями С-Н и О-Н
Кинетика и катализ. 1997. Т.38. №1. С.43-51. РЖ ВИНИТИ
Даты:
| Поступила в редакцию: | 24 июл. 1995 г. |
| Опубликована в печати: | 1 янв. 1997 г. |
Идентификаторы БД:
| Web of science: | WOS:A1997WN06000007 |
| Scopus: | 2-s2.0-0642307408 |
| РИНЦ: | 13256534 |
| Chemical Abstracts: | 1997:190643 |
| OpenAlex: | W2478615249 |