Kinetics of limonene autooxidation

The kinetic parameters of the oxidizability of Iimonene,k _p/(2k _t)^0.5 = 6.0- 10^–3 L^{0 5} mol^–5 s^–0.5, and of the bimolecular radical decomposition of hydroperoxides 2ek _d = 6.0 · 10^–6 L mol^–1 s^–1 were determined at 60 °C The oxidation rate increases in the presence of micro additives of water. Average effective diameters of particles formed in the water-AOT-(n-decane + lirnonene) microemulsion were measured by the light scattering technique. The hydroperoxides were found to affect the size of the microemulsion particles.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 7, pp. 1682–1685, July. 1996.     

Free radical formation during ethylbenzene oxidation catalyzed by cetyltrimethylammonium bromide

The dimer of 2,2"-bis[2-(p-dimethylaminophenyl)indane-1,3-dione] and -tocopherol were used as free radical acceptors in a study of the kinetic regularities of free radical formation during ethylbenzene oxidation by molecular oxygen at 60 °C. The reaction initiated by the -phenylethyl hydroperoxide—cetyltrimethylammonium bromide (CTAB) catalytic system, which generates free radicals. The oxidation kinetics was analyzed using computer simulation.     

The inhibitory activity of natural phenolic antioxidants in the oxidation of lipid substrates

The suppression of the oxidation of triglyceride and methyl esters of lard and olive and sunflower oils by additives of natural phenolic acids (hydroxy and methoxy derivatives ofpara-hydroxybenzoic and cinnamic acids) at 100 °C was studied. The rate constants of the interaction of these acids with peroxyl radicals in the oxidation of cumene at 60 °C were determined by the chemiluminescence method. Caffeic acid is the most efficient lipid antioxidant, exceeding ionol and α-tocopherol. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1119–1122, June, 1997.     

Micellar free radical initiators

The effect of the nature of the surfactant, peroxide (ROOH), and medium on the rate of radical initiation in a surfactant-ROOH mixed micellar system has been studied. Cationic surfactants, as distinct from anionic and nonionic ones, have been found to catalyze ROOH decomposition to form radicals. Cationic surfactants in an organic medium exhibit higher catalytic effect than in an aqueous solution. The catalytic activity of the surfactants is strongly dependent on the counterion nature. The highest catalytic activity is shown by cetyltrimethylammonium chloride.