1989 Volume 22 Issue 4 Pages 407-412
Autoxidations of oleic acid, methyl oleate and ethyl oleate were carried out in the temperature ranges of 343–393 K, 358–378 K and 383–413 K, respectively, and in the oxygen partial pressure range of 0–0.1 MPa. The accumulation and decomposition rates of hydroperoxide were measured under the reaction control condition to obtain the following results. (1) Auto-acceleration in the formation rate of hydroperoxide was clearly observed in the initial stage of the oxidation. (2) A first-order dependence of hydroperoxide formation rate on oxygen partial pressure was found at low oxygen partial pressure, but the rate was almost independent of oxygen partial pressure at comparatively high oxygen partial pressures. (3) A semi-theoretical rate equation of hydroperoxide formation with four kinetic constants was developed to explain the autoxidation behavior of oleic acid and oleates.