Oxidation of Hydrogen-Donating Hydrocarbons from Petroleum Related to Its Inhibiting Effect on the Changes in Dielectric Properties

As the followup to our previous paper, multicomponent hydrogen-donating hydrocarbons derived from petroleum (HHAP) were oxidized at 160 °C in air for 30 h compared with a conventional diphenylamine type antioxidant (Stealer), and the following results were obtained: (1) Judging from the changes in the dissipation factor, carbonyl absorbance by IR, acid value, and oxygen content by elemental analysis, HHAP was barely oxidized under these conditions, although n -paraffin wax was clearly oxidized. (2) Small amounts of oxygen-containing compounds (0.5 wt % in oxygen content), which are acidic materials but not carbonyl compounds, were formed from Stealer under these conditions. (3) In addition to the test results reported in our previous paper, it was reconfirmed by the humidity tests that the oxidation of n -paraffin wax was superbly inhibited by the addition of HHAP, and the dissipation factor was kept low during the humidity tests. With regard to why HHAP was not oxidized under these severe conditions, it was deduced that the free radicals formed from HHAP were stabilized by hydrogen liberated from HHAP itself.