Studies on the Antioxidants XIX: Photooxidation products of tertiary butyl hydroquinone (TBHQ) (bdII)

A series of studies have been made with a view to pursuing the fate of antioxidant molecules during the antioxidation processes. In this study following that reported in the preceding paper, tertiary butyl hydroquinone (TBHQ) in benzene solution was irradiated with ultraviolet rays and the chemical structure and antioxidative activities of the resulting photooxidation products were examined. They were identified as the following three compounds: 2‐(2‐[3′‐tert‐butyl‐4′‐hydroxyphenoxy] ‐ 2‐methyl‐1 ‐propyl)hydroquinone, which was a dimer of the intermediate generated by photorearrangement of the tert‐butyl group and the substrate TBHQ, 2‐(2‐hydroxy‐2‐methyl‐l‐propyl)hydroquinone, which was formed by interaction of the rearranged tert‐butyl group with water, and 2‐ tert‐ butyl‐ 4‐ ethoxy‐phenol, which was formed from a secondary decomposition of the dimer. All of the resulting oxidation products showed antioxidative activity on methyl oleate, soybean oil and lard in the stability test by the active oxygen method (AOM).