Mechanism of the Reaction of Radicals with Peroxides and Dimethyl Sulfoxide in Aqueous Solution

✍ Scribed by Ronit Herscu-Kluska; Alexandra Masarwa; Magal Saphier; Haim Cohen; Dan Meyerstein

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 346 KB
• Volume: 14
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200800218

✦ Synopsis

Abstract

The reactions of methyl and methylperoxyl radicals derived from dimethyl sulfoxide (DMSO) with hydrogen peroxide, peroxymonocarbonate (HCO~4~^−^), and persulfate were studied. The major reaction observed for the hydroperoxides was the abstraction of the hydrogen atom by the radicals. The radicals interact with a lone pair of electrons on the peroxide to produce methanol and formaldehyde. Furthermore, the results indicate that in RO~2~H and RO~2~R′, electron‐withdrawing groups cause a considerable increase in the reactivity of the peroxides towards the radicals and not only towards nucleophiles. The HO~2~^.^/O~2~^.−^ and CO~3~^.−^ radicals react with DMSO to produce methyl radicals. Thus, the formation of the ^.^CH~3~ radicals in the presence of DMSO is not proof of the formation of the ^.^OH radicals in the system. These reactions must be considered when radical processes, such as in biological and catalytic systems, are studied. Especially, the plausible role of HCO~4~^−^ ions in biological systems as a source of oxidative stress cannot be overlooked.