Effect of hydrogenation on the oxidation resistance of decene oligomers

The kinetics of autoxidation and initiated oxidation of PAO-2, PAO-4, PAO-6, and PAO-10⁺ decene oligomer fractions at 140°C after a hydrogenation process was studied. Key reactions in the mechanism of oxidation were identified; the numerical values of the kinetic parameters were determined, and mathematical models, which quantitatively described the experimental data on the consumption of oxygen and the buildup of hydroperoxides during the course of the oxidation of the test samples, were obtained. The oxidation resistances of hydrogenated fractions were compared with each other. It was found that the kinetic parameters of the test samples were similar, and the oxidation of all of the hydrogenated oligomers occurred by approximately the same processes. Using the PAO-2 fraction at 120, 130, and 140°C as an example, the oxidizability of hydrogenated and unhydrogenated samples was compared. It was found that hydrogenation improved all of the kinetic characteristics and, consequently, increased the oxidation resistance of oligomers. However, the oligomers remained readily oxidizable substances, particularly, at elevated temperatures.