engleski

Oxidation of Organic Sulfides by Peroxyl Radicals ; Search for an Adduct Intermediate

The reaction mechanism of dimethyl sulfide oxidation by peroxyl radicals (CCl"3"OO^.^ and CĄCHCl"2"OO^.^ ) in aqueous/alcohol solutions has been studied by means of pulse radiolysis with optical detection in order to gain evidence for the formation of an adduct intermediate, ROO-?S(CH"3")^2^. In the range of 300-650 nm the only absorbing product was the one-electron oxidized species [(CH"3")^2^S..S(CH"3")^2^]^+^ and no indication of an additional absorption attributable to an adduct precursor was found. However, under condition of only 50% conversion of CHCl"2"OO^.^ into the sulfide radical cation, addition of a small amount of I^-^ resulted in the formation of (CH"3")^2^S..I as only product and at a yield equal to that of CHCl"2"OO^.^ radicals. This is explained by the reaction of iodide ions with a precursor of [(CH"3")"2"S..S(CH"3")^2^] species, namely the adduct CHCl"2"OO-^.^S(CH"3"^2^) and is thus taken as a conclusive evidence, although indirect, for existence of this adduct intermediate.

carbon tetrachloride; methylsulfide; peroxyl radicals; pulse radiolysis; reaction mechanism; three-electron bond

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