RADICAL SCAVENGING BY HYDROAROMATICS IN THE PRESENCE OF OXYGEN

The radical scavenging abilities of hydroaromatics toward DPPH (N,N-diphenyl-N'-picrylhydrazyl) in the presence of oxygen were investigated. Tetralin, octahydrophenanthrene (OHP), synthetic H/D (a multicomponent additive containing various hydroaromatics produced by hydrogenation of decrystallized anthracene oil derived from coal tar), and HHAP (a multicomponent additive produced by hydrogenation of a highly aromatic heavy fraction from petroleum) were examined by heating at 50-degrees-C for 3 h with DPPH in air. It was confirmed by the changes in color of the solution and the ESR spectra that those hydroaromatics have obvious radical scavenging abilities and that OHP, synthetic H/D, and HHAP have higher abilities than tetralin. From these experimental results, the additive effects of these hydroaromatics on the deterioration of petroleum products, rubbers, and plastics reported in our previous papers can be attributed to their radical scavenging abilities.