Peroxy species

Inorganic phosphorus- and sulphur-containing peroxy species. . 977... 

The phosphorus-containing peroxy species obtained on reaction of potassium superoxide with diethylchlorophosphate, as shown in equation (23), has also been used to prepare sulphones from sulphoxides76 at 20 °C in reasonable yields. 

Peroxomonosulphate and peroxodisulphate have also been used to oxidize sulphoxides to sulphones in good yields at room temperature. Potassium persulphate (KHS05) readily oxidizes a range of sulphoxides to sulphones at 0°C in yields greater than 90%, in the presence of hydroxy, keto and alkene groups82-84. The mechanism is similar to that observed for other peroxy species, as discussed above. Peroxomonosulphate oxidation has been used as an analytical procedure for the estimation of dimethyl sulphoxide84. 

For the oxidation of ketones, Baeyer-Villiger oxidation of cyclic ketones with monopersuccinic acid in water gives lactones in good results (Eq. 8.22).47 Peroxy species generated from borax in 30% hydrogen peroxide is effective for the Baeyer-Villiger oxidation of... 

On the other hand, because of their inertness, alkanes probably oxidize by a radical mechanism52 shown in Fig. 6.12. If this is so, then it is uncertain how methanol would increase the rate of this reaction. Perhaps by complexing to Ti as in Fig. 6.8, it facilitates homolytic cleavage of the peroxy species or transfer of the OH radical to the alkyl radical. 

Unlike conventional chemical reactions, the altered reactivity of chemical reactions undergoing ultrasonic irradiation is principally due to acoustic cavitation which essentially involves the free radical formation. The ultrasound produces highly reactive free radical species like H and OH radicals from the homolytic cleavage of water. Further they may react with any of other free radicals present or with neutral molecules like 02 and O3 to produce peroxy species, superoxide, hydrogen peroxide or hydrogen. When the aqueous solution is saturated with 02, extra... 

However, this analysis does not teU us whether it is the phenyl and/or cyclohexyl peroxy species that is in error. 

This screening work shows the selective nature of E D D S for transition metal ions in the presence of hardness ions, as compared with other chelants. Moreover, the reduced dye damage demonstrates how well EDDS prevents the formation of hydroxyl radicals from peroxy species and copper ions [32]. 

B. The Fate of the Unstable Peroxy Species The Origin of the Stable Degradation Impurities... 

Catalytic studies have extended the applications of TS-1 from early aromatic hydroxylation to the oxidation of olefins, alkanes, alcohols, amines and thioethers, and to other minor reactions. A combination of three factors is the basis of its effectiveness the high activity of Ti peroxy species, the organophilic properties of the surface and the size of the pores in the range of molecular dimensions. For... 

To achieve the four-electron reduction of O2 to H2O without releasing H2O2 another metal ion such as Cu ion in cytochrome c oxidase is required to stabilize the two-electron reduced peroxy species by forming a bimetallic peroxo complex. This... 

Kubokawa et al. observed that the order of reactivity for various alkenes as regards the initial O2 uptake was pent-l-ene > trans-bni-l-QnQ > propene > buta-1,3-diene > ethene, i.e. it increased with carbon number for the mono-alkenes. All these initial oxygenated complexes showed similar activity for their further oxidation to CO2 and H2O. Although agreeing with Kokes et al. over the initial formation of a peroxy species from propene, Kubokawa et al. concluded that it decomposed to formate and acetate surface species, both from i.r. studies and from an overall O2 propene ratio of —1. Both groups of workers... 

---