Study of synergistic action of mixtures of aromatic amines and phenols during oxidation of hydrocarbons

Abstract

which results in regeneration of the amine, the more effective inhibitor by the hydrogen of phenol, the less effective inhibitor. However, the action of mixtures of various inhibitors has only been studied during oxidation of ethylbenzene, a hydrocarbon. We therefore sought to establish whether there is any synergism due to the radical interaction of inhibitors and, in the case of other hydrocarbons, ascertain the influence of the type of hydrocarbon oxidized on the synergistic effect. Tetralin, cumene and n-decane were oxidized in the presence of N-phenylp-naphthylamine (Neozone D), 2,6-di-tert-butylphenol and mixtures of differing composition, both under conditions of low temperature initiated oxidation and at a temperature of 120 °, when the process took place by a degenerate branched chain mechanism. To describe the efficiency of Neozone-D and 2,6-di-tert-butylphenol during oxidation of tetralin and cumene, we measured the rate constants of the reaction with peroxide radicals of these hydrocarbons (kl). k~ values for tetralin were determined from the dependence of the rate of oxidation on inhibitor concentration [3]. The rate of oxygen absorption was measured by a pressure gauge consisting of a thermostatically controlled reaction vessel with a magnetic stirrer and a capillary, in which kerosine was used as mobile liquid [4]. The small cross-section area of the measuring burette in this apparatus makes it very sensitive to pressure variation in the system. Experiments were carried out at a temperature of 60 °, with azoisobutyrodi-