Peroxydisulfate ion

Kolthoff et al. [42] showed that the thermal decomposition of peroxydisulfate ion yielded two free sulfate radicals according to the following reaction ... 

Fast spectroscopy was also used to probe the reactivity of PBN +. The 266 nm laser excitation of peroxydisulfate ion in aqueous solution at room temperature gives the powerful oxidant SOr, which oxidizes PBN in an exergonic reaction (by about 0.8 eV, see Tables 1 and 5) with k = 3 X 109 dm3 mol-1 s 1. The pseudo-first-order rate constant for the decay of PBN + by reaction with water to give HO-PBN" was 2 x 106 s 1, a relatively slow reaction (k = 3.6 x 104 dm3 mol-1 s-1 at ambient temperature). 

To the best of our knowledge, there is no review about the applications of peroxy-disulfates (S20g ) and its organic salts. The peroxydisulfate ion is one of the strongest... 

Preparative methods based on oxidations by peroxydisulfate have long been known. Peroxydisulfate ions are capable of oxidizing virtually all functional groups, even hydrocarbons. The oxidation of phenol using potassium peroxydisulfate in alkaline solution, to yield a 1,2- or 1,4-dihydroxybenzene, is called the Elbs reaction and it had been already reported in 1893 (equation 12) . 

Wille demonstrated recently the utility of S04 as an oxygen atom donor when it was reacted with two different ten-membered alkynes 24 (equation 22) and 27 (equation 23) . This is the first example of transfer of oxygen atom from peroxydisulfate ion. 

Early experiments by a number of workers demonstrated that dye excited states could function as electron donors (69,92-94). Lindquist (69) showed that the triplet state of fluorescein was quenched by oxygen in basic media with the formation of superoxide anion, by ferric ion in acid media to form ferrous ion, and by peroxydisulfate ions in alkaline solutions. The photo-... 

Gallopo, A. and J. Edwards (1971). Kinetics and mechanism of the spontaneous and metal modified oxidation of ethanol by peroxydisulfate ion. J. Org. Chem. 36,4089 1096. 

Peroxydisulfuric acid, H2S20s, is a colorless solid that has a melting point of 65 °C. The acid and its salts are strong oxidizing agents, and the acid is not very stable. The sodium, potassium, and ammonium salts are most commonly used in oxidation reactions. The peroxydisulfate ion is generated by the anodic oxidation of bisulfate as represented by the equation... 

These reactions are the basis for a commercial preparation of hydrogen peroxide. The 0-0 linkage in the peroxydisulfate ion is rather unstable, so heating these solid compounds produces elemental oxygen ... 

What is the oxidation number of sulfur in S20g , the peroxydisulfate ion ... 

Mechanism The nucleophilic attack of phenoxide through para position of the aromatic ring carbon on the peroxide oxygen of the peroxydisulfate ion forms the intermediate persulfate 7.44. Hydrolysis of 7.44 gives the p-hydroquinone 7.30. 

Chromium has been investigated as a coating for steel cans. The thickness of the chromium film is determined by dissolving a sample of a can in acid and oxidizing the resulting Cr3+ to Cr2072- with the peroxydisulfate ion ... 

The nucleophilic radicals formed by the silver-catalyzed, oxidative decarboxylation of carboxylic acids by peroxydisulfate ions attack protonated imidazoles mainly at the 2-... 

Homogeneous oxidants Peroxydisulfate ion, S20g (often called persulfate), is a strong oxidant in acid solution in the presence of silver ion as catalyst. The reaction... 

IV. Stoichiometry of the Reaction of Peroxydisulfate Ion with Hydrogen Peroxide and Evidence of Acidity Constant of the HOj Radical... 

Radical substitution reactions include alkylations and arylations in the main. Nucleophilic radicals produced by the silver-catalyzed oxidative decarboxylation of carboxylic acids (by peroxydisulfate ion) attack proton-ated azoles at the most electron-deficient sites.Thus, imidazole and 1-alkylimidazoles are methylated exclusively at C-2 in rather low yields. The use of isopropyl and t-butyl radicals gives improved yields, but benzyl and acyl radicals tend to dimerize rather than substitute the... 

The oxidation of sulfacetamide sodium by peroxydisulfate ion to azobenzene derivatives follows second-order kinetics. The reaction is very sensitive to pH and the rate increases with increase in pH in the region 1.2-7.76. The rate decreases with decrease in dielectric constant of the medium, and a plot between log k2 and D 1 is linear. The reacion is inhibited by the presence of diphenylpicryl hydrazyl (102,103). 

A newly emerging class of reactions is oxidative substitution. An aromatic molecule reacts with a nucleophile to give a substitution product, a proton and two electrons or their equivalent. The aromatic molecule is first oxidized by a metal ion (or even an anode124)) to a radical cation intermediate which then is trapped and converted to product. Consider the reaction of alkylbenzenes with copper(II) chloride and peroxydisulfate ion. The peroxy compound converts toluene, for example, into its radical cation which is trapped in a reaction with the copper salt. Aromatiza-tion then gives products which are mostly o- and p-chlorotoluene, Scheme 15. In the... 

These authors describe the polymerization of acrylonitrile (AN), in systems in which peroxydisulfate ions S2Og, already present in the electrolyte, are decomposed following the well known reaction25 ... 

It is remarkable, then, that hi the peroxydisulfate ion the peroxy group... 

Recently it has been shown that peroxydisulfate ion or, more correctly, S04 formed by homolytic fission of S2Os-, is a particularly convenient reagent for the oxidation of aromatics (including pyridine, benzene and chlorobenzene) in water or aqueous acetonitrile solutions (Ledwith and Russell, 1974a, b, c). These reactions have mechanistic significance in respect of the more complex oxidations outlined above and may be represented overall as in eqn (42). It is interesting that, generated in this manner, the arene cation... 

Ledwith and Russell (1974b) have found that chlorination of benzene, toluene and other aromatic molecules is easily achieved in aqueous acetonitrile containing sodium peroxydisulfate and copper(II) chloride. Toluene, for example, gives no benzyl chloride but a mixture of chlorotoluenes (58% o-, 4% m-, and 38% p-) consistent with the spin distribution in the toluene cation radical. The amount of copper chloride used can be catalytic provided another source of chloride ion (LiCl) is added. Reaction is attributed to the very fast transfer of chlorine atom from copper(II) chloride to the cation radical (132) the metal halide is thus regarded as a trap for the aromatic cation radical. In the absence of copper(II) chloride, reactions of toluene with peroxydisulfate ion and chloride ion give... 

A rather special case of pyridination occurs during oxidation of pyridine in aqueous solution by peroxydisulfate ion (Ledwith and Russell, 1974a). Very high yields of isomeric pyridylpyridinium salts... 

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