Peroxydisulfates

The electrolytic processes for commercial production of hydrogen peroxide are based on (/) the oxidation of sulfuric acid or sulfates to peroxydisulfuric acid [13445-49-3] (peroxydisulfates) with the formation of hydrogen and (2) the double hydrolysis of the peroxydisulfuric acid (peroxydisulfates) to Caro s acid and then hydrogen peroxide. To avoid electrolysis of water, smooth platinum electrodes are used because of the high oxygen overvoltage. The overall reaction is... 

Potassium peroxymonosulfate, introduced in the late 1980s, is finding increasing use as an auxiUary oxidant for shock treatment and oxidation of chloramines. Sodium peroxydisulfate is also being sold for shock treatment, however, it is less reactive than peroxymonosulfate. Mixtures of sodium peroxydisulfate and calcium hypochlorite can be used for shock treatment (28). Disadvantages of peroxymonosulfate and peroxydisulfate are they do not provide a disinfectant residual and peroxymonosulfate oxidizes urea and chloramines to nitrate ion, which is a nutrient for algae. 

The development of the autoxidation of alkyl anthraquinones led to a rapid iacrease ia the production of H2O2 but a sharp decline in the importance of the electrolytic process. In 1991 the total North American, Western European, and Japanese capacity for H2O2 production was more than 870,000 t (77). No H2O2 was produced by the electrolytic peroxydisulfate process. The last plant using this process closed in 1983. 

Ammonium peroxydisulfate [7727-54-0] M 228.2, m dec when heated wet liberating oxygen, d 1.98. Recrystd at room temperature from EtOH/water. 

Potassium peroxydisulfate (potassium persulfate) [7727-21-1] M 270.3. Crystd twice from distilled water (lOmL/g) and dried at 50° in a vacuum desiccator. 

Chemical Designations-Sy/io/ nzs Ammonium Peroxydisulfate Peroxydisulfuric Acid, Diammonium Salt Chemical Formula (NH4)2SjOg. 

Other oxidizing agents that can be used include nitric acid, hydrogen peroxide, peroxydisulfate, chlorate and the pervanadyl ion. The anhydrous... 

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

In some cases, due to the highly polar character of the sulfate radicals, peroxydisulfate initiators can provide slow polymerization rates with some apolar monomers since the polar sulfate radicals cannot easily penetrate into the swollen micelle structures containing apolar monomers. The use of mercaptans together with the peroxydisulfate type initiators is another method to obtain higher polymerization rates [43]. The mercaptyl radicals are more apolar relative to the free sulfate radicals and can easily interact with the apolar monomers to provide higher polymerization rates. 

Recently, Smigol et al. [75] extensively studied emulsifier-free emulsion polymerization of different monomers including styrene, methyl methacrylate, and glycidyl methacrylate in an aqueous medium by using potassium peroxydisulfate as the initiator. In this study. 

Photolysis or thermolysis of persulfate ion (41) (also called peroxydisulfate) results in hoinolysis of the 0-0 bond and formation of two sulfate radical anions. The thermal reaction in aqueous media has been widely studied."51 232 The rate of decomposition is a complex function of pH, ionic strength, and concentration. Initiator efficiencies for persulfate in emulsion polymerization are low (0.1-0.3) and depend upon reaction conditions (Le. temperature, initiator concentration)."33... 

Fluka purum-grade ammonium peroxydisulfate was used by the submitter. The checkers used ACS reagent-grade material available from Fisher Scientific Company. 

Alkylation of protonated nitrogen heterocycles (e.g., pyridines, quinolines) can be accomplished by treatment with a carboxylic acid, silver nitrate, sulfuric acid, and ammonium peroxydisulfate. The R group can be primary, secondary, or tertiary. The attacking species is R% formed by " ... 

ESR experiments employing in situ photolytic decomposition of the peroxydisulfate anion (S20g ) have been carried out to study the reaction of S04 with aliphatic sulfoxides. In the case of dimethyl sulfoxide three radicals are detected ( CHj, CH3 S02, CH2 S(0)CH3), the proportion being pH-dependent. The reaction is assumed to proceed via an initially formed radical cation (not detected) which would be rapidly hydrated to give an intermediate identical with that generated by OH addition on the sulfoxide. Such a process parallels the rapid hydration of radical cations formed from thiophene in their reactions with SO/ and... 

Oxidation of the complexes [Ag(Py)4][MoF6] and [Ag(Py)2][UF6] in acetonitrile by MoF6 and UF6, respectively, leads to the silver(III) compounds [Ag(Py)4(NCMe)][MoF6]3 and [Ag(Py)2(NC-Me)3][UF6]3, which are strong oxidizing agents.167 Other pyridine silver(III) complexes have been obtained by oxidation of silver nitrate and ammonia with ammonium peroxydisulfate in aqueous... 

A breaker an enzyme (at T<140°F), strong oxidizing agent, or an acid, is used to depolymerize polysaccharides and break crosslinks such that viscosity declines at a controlled rate so that the proppant may be deposited in the fracture. Too rapid proppant dropout would cause a premature "sand-out" which prevents future extension of the fracture. Peroxydisulfates are the most frequently used breakers. Less reactive organic peroxides may be preferred for high temperature formations (85). 

Ghasemi et al. [24] have obtained nanostructured Pb02 (50-100 nm) using [5-PbO precursor and in the presence of ammonium peroxydisulfate as an oxidant. Here, the ultrasonication dispersed and then cracked the [5-PbO particles, thereby increasing the contribution of their surface area. Such an ultrasonic treatment resulted in an enhancement in the oxidation of PbO to Pb02 has been observed. Ultrasonic waves also have been found to inhibit the formation of Pb02 particles larger than 150 nm. 

Ans. If you calculate the oxidation number assuming that the oxygen atoms are normal oxide ions, you get an answer +7, which is greater than the maximum oxidation number for sulfur. That must mean that one of the pairs of oxygen atoms is a peroxide, and thus the sulfur must be in its highest oxidation number, +6. The ion is peroxydisulfate ... 

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