Detection of Radicals at the Photolysis of tert-Butyl Hydroperoxide in DMSO and water

The decomposition of tert-butyl hydroperoxide by photochemically induced reactions in DMSO2) and water was investigated by cw-e.s.r. spectroscopy. The products tert-butylperoxyl, methyl and sulfur-centered free radicals were identified. The tert-butoxyl free radical is involved in the primary process as shown by time-resolved e.s.r. technique. On the basis of directly identified radical species, a mechanism for the photochemically induced reactions of tert-butyl hydroperoxide in DMSO is proposed. At concentrations below 0.8 mol.l-1 the radical formation from tert-butyl hydroperoxide proceeds by cleavage of the O-O bond rather than by hydrogen abstraction.