Peroxytungstic acid

Sodium tungstate has also been used as a catalyst in the oxidation of dimethyl sulphoxide to the sulphone36. The kinetics of this reaction have been studied in great detail and it has been shown that oxygen transfer to the sulphoxide takes place via two peroxytungstic acid species (HW05 and HWOg ). 

The catalytic epoxidation proceeds via the formation of peroxytungstic acid. Similarly, other metal catalysts are effective in the H2O2 oxidation. Aqueous conditions are not appropriate for epoxidations since epoxides are prone to undergo acid-catalyzed hydrolysis36. Polymer-anchored catalysts are conveniently separated from the reaction mixture after catalyzed H2O2 epoxidations (equation 8)9. 

Oxidation of mandelic acid by H2O2, catalyzed by Fe ", is only 50% inhibited by the presence of OH radical traps and formation of an active Fe(IV) species may be a possibility. However it is thought more likely that the uninhibited pathway involves cage reaction of newly formed OH radicals. Peroxytungstic acids are formed in the H2O2 oxidation of dmso catalyzed by WO4 . An extensive study of the oxidation of cobalt(II) by m-Cl-perbenzoic acid in 90% acetic acid media has appeared. The mechanism is complex involving a second-order dependence on [Co(II)] and various dimeric and trimeric 0x0- and hydroxo-bridged species, are formed in the course of the reaction. 

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