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Reactive oxygen species and sulfoxyl radicals in the aerobic decomposition of thioureas dioxides.
Simoyi-RH; Svarovsky-SA; Mundoma-CM; Makarov-SV
Abstr Pap - Am Chem Soc 1999 Aug; 218(Part 2):U375
Thioureas dioxides (aminoiminomethane sulfinic acids) are stable in acidic and neutral environments, but rapidly decompose in basic medium to produce a variety of products that include sulfur dioxide. A detailed kinetic and mechanistic study of the decomposition of thioureas dioxides in basic medium has shown a process that produces dithionite, S2042-, which is preceded by an induction period which persists for as long as molecular oxygen is present in the reaction solution. The complete consumption of molecular oxygen is a prerequisite for the formation of S2042-. The proposed mechanism involves the initial formation of sulfoxylate ion, SO22-, through heterolytic cleavage of C-S bond. The sulfoxylate ion then reacts with oxygen to produce a series of highly reactive species. Among some of the intermediates detected in the decomposition of thioureas dioxides are the sulfite radical, superoxide, peroxide, and hydroxyl radical. It is suggested that these reactive species are responsible for the toxicity observed in most thioureas.
Free-radicals; Free-radical-generation; Sulfur-compounds; Toxic-effects; Ureas; Thioureas; Chemical-deposition; Chemical-reactions
Reuben H. Simoyi, Department of Chemistry, West Virginia University, P.O. Box 6045, Morgantown, WV 26506
Abstract; Conference/Symposia Proceedings
Abstracts of Papers - American Chemical Society
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