Peroxydisulfuric Acid

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... 

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

Per-saiire, /. per acid, (if containing the -0-0-group) peroxy acid, -schwefelsaure, /. per-sulfuric acid (peroxydisulfuric acid, HaSaOg). Perseit, n. perseitol, perseite. 

In concentrated sulfuric acid solutions at HAP, the adsorbed HS04 ions are converted, according to reaction (15.57), to HS 04 radicals which dimerize, forming peroxydisulfuric (persulfuric) acid H2S2O8. This acid is the intermediate for one of the commercialized methods of hydrogen peroxide production. The first efforts toward the electrosynthesis of peroxydisulfuric acid go back to 1878 commercial production started in 1908. The standard electrode potential of the overall reaction... 

One preparation of H202 (m.p. -0.43 °C and b.p. 150.2 °C) involves converting sulfuric acid to per-oxydisulfuric acid, H2S208, which is done by electrolysis of cold, concentrated sulfuric acid. H202 is obtained by hydrolysis of peroxydisulfuric acid,... 

Peroxymonosulfuric acid (historically known as Caro s acid), H2S05, results when peroxydisulfuric acid reacts with a limited amount of water,... 

The real potential of peroxydisulfuric acid for the synthesis of highly nitrated arylenes was brought to light by research conducted at the Naval Air Warfare Center, Weapons Division, China Some of the highly nitrated polynitroarylenes syn-... 

Some substrates show limited solubility in sulfuric acid solutions and this can affect the rate of oxidation. However, the main factor for slow amine oxidation is due to the high concentration of protonated amine under these highly acidic conditions. Under these conditions only weakly basic amines have a high enough concentration of unprotonated form to permit oxidation to occur. As a result, sulfuric acid solutions of peroxydisulfuric acid are only useful for the oxidation of very weakly basic amines. Peroxydisulfuric acid oxidizes trinitrotoluidines to tetranitrotoluenes (Table4.1, Entry 3) but leaves the more basic dinitrotoluidines unaffected. The opposite is true of peroxyacids like peroxytrifluoroacetic acid and so the reagents are very much complementary. 

It is unsurprising that some substrates react with peroxydisulfuric acid faster when in 100 % sulfuric acid than in oleum. A striking example of this is illustrated by the oxidation of 2,6-dinitroaniline to 1,2,3-trinitrobenzene in 56% yield when the sulfuric acid concentration is 96 % whereas in 20 % oleum this substrate is unaffeeted. ... 

Products from peroxydisulftiric acid oxidations are usually isolated in high yield and high purity with potential by-products such as azo, azoxy and nitroso compounds usually absent. Product isolation is usually facile the product either precipitates from solution or can be extracted, with any unreacted amine remaining in the acid liquors. Peroxydisulfuric acid is, however, a very strong oxidant and some substrates are rapidly destroyed, which is the case for polynitrophenylenediamines. The reactivity of such substrates can be moderated by prior... 

Peroxytriflic acid (CF3SO4H) is prepared in situ from the addition of 90-98 % hydrogen peroxide to an excess of triflic acid. Peroxytriflic acid was first reported by Nielsen and co-workers and is possibly the most powerful peroxyacid known. The full potential of peroxytriflic acid has not been explored but it is reported to oxidize the weakly basic amine 2,3,4,5,6-pentanitroaniline (31) to hexanitrobenzene (55) in 90 % yield peroxydisulfuric acid achieves the same conversion in only 58 % yield. ... 

Trifluoroacetic acid (CF3CO3H) sits between peroxyacetic acid and peroxydisulfuric acid in oxidizing potential. Anhydrous solutions of peroxytrifluoroacetic acid in methylene chloride can be prepared by the addition of 90 %+ hydrogen peroxide to a solution of trifluoroacetic anhydride in methylene chloride containing a trace of sulfuric acid. Solutions of peroxytrifluoroacetic acid prepared from less concentrated hydrogen peroxide solution or trifluoroacetic acid are less reactive to arylamines. 

TNT has been used as a starting material for the synthesis of 2,3,4,5,6-pentani-troaniline (see Section 4.8.4), and hence, for the synthesis of hexanitrobenzene via oxidation with peroxydisulfuric acid, and l,3,5-triamino-2,4,6-trinitrobenzene (TATB) via nucleophilic displacement with ammonia. " " ... 

It is possible to oxidize the amino group of 2,3,4.5-tetrafluoro-6-nitroaniline to give the dinitro compound 2.229 The oxidation is successfully accomplished with peroxydisulfuric acid on a scale of 100 mg. but on a 1-g scale violent gassing occurs and most of the product is lost. However, the oxidation is successfully achieved on a 10-g scale, and with a better yield, using trifluoroperacetic acid.229... 

Despite many attempts it has not been possible to oxidize 2-substituted 1,2,3-triazoles 382 to the corresponding 1-oxides 326. Peracetic acid, 3-chloroperbenzoic acid, dichloropermaleic acid, trifluoroperacetic acid, peroxydisulfuric acid, and f-pentyl hydrogen peroxide in the presence of molybdenum pentachloride all failed to oxidize 382 (1981JCS(P1)503). Alkylation of 1-hydroxytriazoles 443 invariantly produced the isomeric 3-substituted 1,2,3-triazole 1-oxides 448 (see Scheme 132). However, the 2-substituted 1,2,3-triazole 1-oxides 326 can be prepared by oxidative cyclization of 2-hydroxyiminohydrazones (1,2-hydrazonooximes, a-hydrazonooximes) 345 or by cyclization of azoxyoximes 169. Additional methods of more limited scope are reaction of nitroisoxazoles 353 with aryl-diazonium ion and base, and reaction of nitroimidazoles 355 with hydroxy-amine- or amine-induced rearrangement of nitro-substituted furoxanes 357. 

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... 

Although peroxydisulfuric acid is itself of little importance except as an intermediate in the preparation of H202, the salts are important oxidizing agents for synthetic purposes. 

SYNS ANTHION PEROXYDISULFURIC ACID DIPOTASSIUM SALT POTASSIUM PEROXY-DISULFATE POTASSIUM PEROXYDISULPHATE POTASSIUM PERSULFATE pOT)... 

Combustible when exposed to heat, flame, or oxidizers. Potentially explosive reaction with aluminum chloride + nitromethane (at 110°C/100 bar), formaldehyde, peroxydisulfuric acid, peroxymonosulfuric acid, sodium nitrite + heat. Violent reaction with aluminum chloride + nitrobenzene (at... 

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