Studies on the antioxidants XVIII: Oxidation product of tertiary butyl hydroquinone (TBHQ) (I)

Abstract

Abstract To explain the mechanism of antioxidants, it is important to know their chemical changes during the process of their prevention of autoxidation. Therefore, we have carried out a series of studies on these changes. In this study, the chemical structures and antioxidative activities of the oxides isolated by irradiation with ultraviolet rays were examined by using tertiary butyl hydroquinone (TBHQ). Two of the isolated products were identified as follows: one was a golden needle crystal, 2‐tert‐butyl‐ p ‐benzoquinone, and the other was a white prism‐like crystal, 2,2‐dimethyl‐5‐hydroxy‐2,3‐dihydrobenzo(b)furan, which was formed by dehydrogenation of the OH group and the methyl group in the rearranged tert‐butyl group at the ortho position, so that furan rings were formed in the molecules. When the stability of these two products was tested on three different basic oils by the active oxygen method (AOM), quinone did not show any antioxidative activity, but the benzofuran derivative showed a strong antioxidative activity on lard and methyl oleate.