Interaction of tert -butyl Hydroperoxide with Hypochlorous Acid. A Spin Trapping and Chemiluminescence Study

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The formation of radical species during the reaction of tert-butyl hydroperoxide and hypochlorous acid has been investigated by spin trapping and chemiluminescence. A superposition of two signals appeared incubating tert-butyl hydroperoxide with hypochlorous acid in the presence of the spin trap f -(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN). The first signal (aN = 1.537mT, agH = 0.148mT) was an oxidation product of POBN caused by the action of hypochlorous acid. The second spin adduct (aN = 1.484mT, agH = 0.233mT) was derived from a radical species that was formed in the result of reaction of tert-butyl hydroperoxide with hypochlorous acid. Similarly, a superposition of two signals was also obtained using the spin trap N-tert-butyl- f -phenylnitrone (PBN). tert-Butyl hydroperoxide was also treated with Fe2+ or Ce4+ in the presence of POBN. Using Fe2+ a spin adduct with a N= 1.633mT and agH = 0.276mT was observed. The major spin adduct formed with Ce4+ was characterised by αN = 1.480mT and agH = 0.233mT. The reaction of tert-butyl hydroperoxide with hypochlorous acid was accompanied by a light emission, that time profile and intensity were identical to those emission using Ce4+. The addition of Fe2+ to tert-butyl hydroperoxide yielded a much smaller chemiluminescence. Thus, tert-butyl hydroperoxide yielded in its reaction with hypochlorous acid or Ce4+ the same spin adduct and the same luminescence profile. Because Ce4+ is known to oxidise organic hydroperoxides to peroxyl radical species, it can be concluded that a similar reaction takes place in the case of hypochlorous acid.