Dissociation energies of O–H bonds in 3-pyridinols
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- 作者：T. G. Denisova ; E. T. Denisov
- 关键词：rate constants ; intersecting parabolas model ; 3 ; pyridinols ; activation energies ; bond dissociation energies ; radical stabilization energies
- 刊名：Kinetics and Catalysis
- 出版年：2016
- 出版时间：November 2016
- 年：2016
- 卷：57
- 期：6
- 页码：723-730
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Catalysis; Physical Chemistry;
- 出版者：Pleiades Publishing
- ISSN：1608-3210
- 卷排序：57
文摘
The O−H bond dissociation energy (DO−H) has been estimated for 20 substituted 3-pyridinols and a substituted 3-pyrimidinol from experimental kinetic data by the intersecting parabolas method using α-tocopherol and 4-methoxyphenol as reference compounds. The following DO−H values (kJ/mol) have been obtained: 363.7 for 3-pyridinol, 365.3 for 2-alkyl-3-pyridinols (five compounds), 358.8 for 2-alkyl-6-methyl-3-pyridinols (six compounds), 378.1 for 5-benzyl-3-pyridinol, 353.2 for 2,4,6-trimethyl-3-pyridinol, 340.9 for 2-benzyl-6-methoxy-3-pyridinol, 345.8 for 2,6-dimethoxy-5-benzyl-3-pyridinol, 381.7 for 2-ethyl-4-nitro-6-methyl-3-pyridinol, 376.8 for 2-isopropyl-4-nitro-6-methyl-3-pyridinol, 318.3 for 2,4-dimethyl-6-dimethylamino-3-pyridinol, 357.3 for mexidol, and 322.2 for 2,4-dimethyl-6-dimethylamino-3-pyrimidinol. The substituent effect on the O−H bond dissociation energy in 3-pyridinols is considered. The stabilization energies of pyridinoxyl and phenoxyl radicals are compared. The activation energies and rate constants have been calculated for a series of reactions of various radicals with 3-pyridinols.