1104 J. Phys. Chem. A, Vol. 109, No. 6, 2005
ClO2 + HSO3- h [O2Cl-SO3H-]; rapid
[O2Cl-SO3H-] + ClO2 + H2O f
Chigwada and Simoyi
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(R21)
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The rapid formation of chlorite accelerates the reaction. Adduct
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nucleophiles has been recently reported by Nagypal et al. on
the reaction of chlorine dioxide with thiosulfate and tetrathion-
ate.46,47 These are very rapid reactions with rates of the R21-
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studies have been reported with bisulfite, one would assume
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Our studies, in this manuscript, have shown that the oxidation
kinetics of TMTU by chlorite is more complex than a
comparable oxidation of the unsubstituted thiourea.28 TMTU
reactions are much faster and possess a much more complex
behavior with respect to acid. Most of the complexity lies in
the reactivities of the most important metabolite of TMTU, the
sulfinic acid. While it is easily oxidized to the sulfonic acid,
that route quickly terminates as further reaction from that
metabolite is very slow. What could be most important is the
ease by which the C-S bond is cleaved in the sulfinic acid
because in aerobic conditions, we expect a concomitant produc-
tion of reactive oxygen species that might bring with them
inadvertent toxicity.42
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Acknowledgment. We would like to thank Alice Chanakira
for running most of the UV spectra of the reactants, products,
and intermediates (Figure 1) and subsequently evaluating the
various absorptivity coefficients and stoichiometric ratios. This
work was supported by Research Grant Numbers CHE 0137435,
CHE 0341152, and CHE 0341769 from the National Science
Foundation.
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