Oxidation of Lipids. II. Rate of Inhibition of Oxidation by α-Tocopherol and Hindered Phenols Measured by Chemiluminescence

The rate constants for the interactions of peroxyl radicals with α-tocopherol and hindered phenols were determined by chemiluminescence method. The thermal decomposition of di-t-butyl diperoxyoxalate in o-dichlorobenzene with and without ethylbenzene was found to give chemiluminescence under oxygen. 9,10-Dibromoanthracene was an effective activator. The addition of 1-tetralyl hydroperoxide gave chemiluminescence both in the presence and absence of oxygen, while the addition of t-butyl hydroperoxide suppressed the chemiluminescence almost completely even under oxygen. The addition of α-tocopherol and phenols also diminished the chemiluminescence, but after reaching the minimum intensity it again increased as the inhibitors were consumed. The rate constants for the scavenging of 1-phenylethylperoxyl radical by α-tocopherol, 2,4,6-tri-t-butylphenol and 2,6-di-t-butyl-4-methylphenol were obtained as 1.5×105, 1.2×104, and 1.0×104 M−1 s−1 (1 M=1 mol dm−3) respectively.