The Oxidation of Solubilised and Emulsified Oils

Abstract

Abstract Oxidation rates of aqueous dispersions of methyl linoleate emulsified and solubilised by potassium laurate and cetomacrogol, have been measured manometrically at 40°. Emulsions of methyl linoleate oxidised at a greater rate than solutions. The relation between concentration of surface-active agent and oxidation rate of emulsions is complex, and appears to depend on the relative amounts of emulsified and solubilised oil present. Poor agreement was obtained between oxidation rates calculated from peroxide values, chemical and polarographic, and those calculated from oxygen uptake. The results are discussed. An increase in light absorption at 234 mμ in the early stages of oxidation was observed. An uptake of 2.5 mol. oxygen per mol. of methyl linoleate was estimated to occur during the primary oxidation reaction in the presence of cetomacrogol, and 1.5 mol. oxygen per mol. of methyl linoleate in potassium laurate dispersions. The possible mechanism of the reaction and the nature of the oxidation by-products are discussed.