Abstract: Efficiency of the inhibiting action of phenol-based antioxidants (AO) was studied in initiated oxidation of methyl oleate (MO). The following AO were examined: hydroxybenzene (I), tyrosol (4-2'-hydroxyethylphenol) (II), 2-tert-butyltyrosol (III), 2,6-di-teri-butyltyrosol (IV), 4-3'-hydroxypropylphenol (V), 2,6-ditert-butylphenol (VI), dibunol (2,6-di-tert-butyl-4-methylphenol) (VII), and alpha-tocopherol (VIII). The rate constants k(7) determining the activity of AO in the reaction with peroxide radicals were equal to (0.94, 0.97, 0.93, 0.75, 0.92, 1.30, and 360.00) x 10(4) M-1 s(-1) for compounds II, III, IV, V, VI, VII, VIII, respectively. For inhibitors H-VI, VIII, the dependence of the induction period on the AO concentration was of an extreme character, and the most efficient concentrations of AO (C-max) were equal to (0.7, 1.0, 1.6, 1.0, 1.1, and 2.5) x 10(-3) M, respectively. The efficiency of inhibitors (tau(max) and C-max) was demonstrated to rise with increasing extent of shielding of the OH group and shortening of the chain of a substituent in the para position. Using the stationary photolysis method, the rate constants of disproportionation (k(g)) of phenoxy radicals of inhibitors I, III, VII, and VIII were evaluated and equal to (0.52, 2.38, 3.40, and 0.94) x 10(3) M-1 s(-1), respectively, at 20degreesC. It was shown that the k(9) value depended on the extent of shielding of phenoxy radicals. The rate constants (k(10, eff)) were determined for the reaction of phenoxy radicals with lipids with various extents of unsaturation: MO, linoleic and arachidonic acids. The values of k(10, eff) for the reaction of phenoxy radicals of I, III, VII, and VIII with linoleic acid (20degreesC) were equal to (0.69, 0.48, 0.09, and 0.49) x 10(2) M-1 s(-1), respectively. It was found that in MO oxidation, the k(10, eff) values decreased in proportion to the number of ortho-tert-butyl substituents in an AO molecule. For the reactions of phenoxy radicals of inhibitor VII with MO, linoleic and arachidonic acids, the values of k(10, eff) increased with the number of double bonds in a substrate and were equal to (0.09 +/- 0.01, 0.09 +/- 0.01, and 0.64 +/- 0.04) x 10(2) M-1 s(-1), respectively. The k(10, eff) rate constants for the reaction of phenoxy radicals of compound VIII with the same lipids were equal to (0.20 +/- 0.04, 0.49 +/- 0.01, and 0.74 +/- 0.12) x 10(2) M-1 s(-1), respectively.

Cite: Storozhok N.M. , Gureeva N.V. , Krysin A.P. , Borisenko V.E. , Rusina I.F. , Khrapova N.G. , Burlakova E.B.
Interrelation between the inhibiting properties and the activity of phenoxy radicals of antioxidants different in structure
Kinetics and Catalysis. 2004. V.45. N4. P.488-496. DOI: 10.1023/B:KICA.0000038075.46269.a6 WOS Scopus РИНЦ

ArticleLinkType.TRANSLATED_TO_ORIGINAL: Сторожок Н.М. , Гуреева Н.В. , Крысин А.П. , Борисенко В.Е. , Русина И.Ф. , Храпова Н.Г. , Бурлакова Е.Б.
Взаимосвязь между ингибирующими свойствами и активностью феноксильных радикалов антиоксидантов различного химического строения
Кинетика и катализ. 2004. Т.45. №4. С.519-527. РИНЦ

Dates:

Published print:

Jul 1, 2004

Identifiers:

Web of science	WOS:000223776200005
Scopus	2-s2.0-4444250324
Elibrary	13447184
OpenAlex	W2066586830

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