The kinetics and product studies of oxidation of eight olefins 143 by ClO, in H 2 0 in the pH range 3-7 are described. The reaction is faster as the pH decreases. At pH < 4, CIO, reacts equimolarly with olefins to yield isomeric mixtures of chlorohydrines and 1,2-dioxygenated products, following the equation:The order of reactivity is: (E)-stilbene > indene > 8-methylstyrene > acenaphthylene > a-methylstyrene > styrene > cyclohexene > allylbenzene. A multi-stage radical-cation mechanism is proposed, in which an initial reversible protonation:C102 + H+ * [HCIOJ+ is followed by an electron-transfer stage (rate-determining):The cation-radical thus produced, adds rapidly an additional ClO, to form dioxygenated products. The chlorohydrines most likely arise from HClO additions to the olefinic double bonds, which, in turn, generate from dismutation of 2 HCIO, into HClO + H+ + CIO;.Unlike Cl,, the disinfection of drinking water by CIO, [ 11 does not appear to generate mutagenic or suspected carcinogenic trihalomethanes [2] and produces much less toxic chlorinated organic compounds [3]. This prompted the development of CIO, as a viable substitute for C1, for the disinfection of drinking water. In spite of its growing environmental importance, there are only a few studies on the nature of the reaction in H,O between C10, and organic functionalities. Whereas C10, functions as an electron oxidant towards tertiary amines [4] and phenols [5], the reaction with olefins was hitherto viewed to involve free-radical attacks both on the allylic sp3-C-atoms and the olefinic sp2-Catoms [6]. This brings up the interesting question as to whether the reaction mechanism of CIO, varies with the substrate demand. Towards this end, we undertook a study aimed at establishing the mechanisms of the reaction between C10, in H,O and two types of olefins. One, containing allylic sites such as indene (l), LY-and P-methylstyrenes (3 and 5, respectively), allylbenzene (S), and cyclohexene (7), and the other one, comprising non-allylic olefins such as acenaphthylene (4), (E)-stilbene (2), and styrene (6). The reaction
