H2SO

Caro s acid, H2SOS. See persulphuric acid, carotene, C4qHs6- M.p. 18 J-J82°C. Carotene... 

G. Treat with cone. H2SO, then heat (p. 331). 

HjIO orthoperiodic acid H2SOS peroxomonosulfuric acid... 

Peroxophosphoric Acids and Their Salts. In its usual impure form (H PO is the main contaminant), peroxomonophosphoric acid [13598-52-2] (5), is a viscous, coloress Hquid. The three ionization constants for peroxomonophosphoric acid are pifj = 1.1, P-A2 = 5.5, and pK (peroxide proton) = 12.8 (44). Oxidations comparable to those of peroxomonosulfuric acid, H2SO, occur in acid solutions of ca pH 2, but at higher pH values, H PO becomes less reactive as an oxidant and more unstable with respect to decomposition (44). The stmcture of H PO is probably similar to that of... 

Peroxomonosulfuric acid [7722-86-3] H2SO, when pure, forms colorless crystals that melt with decomposition at 45°C. One of its protons is strong, as ia sulfuric acid, but its other proton, which is on the peroxide group, is weak (pH = 9.4). Peroxomonosulfuric acid is a strong oxidi2iag agent ... 

In a typical isothermal process, 70% hydrogen peroxide is added to 98% sulfuric acid, and subjected to rapid stirring and efficient cooling, so that the temperature does not rise to above 15°C. If equimolar quantities of reactants are used, the product contains 42% H2SO and 10% H2O2. Although the reaction may seem simple, many of its features are critically important and it should only be attempted foUowiag advice from speciaUsts. 

Potassium salts of the peroxides (27—29) are prepared from the reaction of Caro s acid [7722-86-3] H2SO, with acyl chlorides, chloroformates, or organosulfonyl chlorides in the presence of potassium hydroxide (44). 

The catalysts used in the industrial alkylation processes are strong Hquid acids, either sulfuric acid [7664-93-9] (H2SO or hydrofluoric acid [7664-39-3] (HE). Other strong acids have been shown to be capable of alkylation in the laboratory but have not been used commercially. Aluminum chloride [7446-70-0] (AlCl ) is suitable for the alkylation of isobutane with ethylene (12). Super acids, such as trifluoromethanesulfonic acid [1493-13-6] also produce alkylate (13). SoHd strong acid catalysts, such as Y-type zeoHte or BE -promoted acidic ion-exchange resin, have also been investigated (14—16). 

Values are for neutral alum solutions commercial alum liquor contains excess H2SO and values mn about 0.5 pH units lower slightly basic alum solutions, some excess AI2O2, have values of about 0.5 pH units higher. 

Nitroso compounds are formed selectively via the oxidation of a primary aromatic amine with Caro s acid [7722-86-3] (H2SO ) or Oxone (Du Pont trademark) monopersulfate compound (2KHSO KHSO K SO aniline black [13007-86-8] is obtained if the oxidation is carried out with salts of persulfiiric acid (31). Oxidation of aromatic amines to nitro compounds can be carried out with peroxytrifluoroacetic acid (32). Hydrogen peroxide with acetonitrile converts aniline in a methanol solution to azoxybenzene [495-48-7] (33), perborate in glacial acetic acid yields azobenzene [103-33-3] (34). 

By-Products and Waste Disposal. A by-product of sulfamic acid manufacturing is fuming sulfuric acid or dilute sulfuric acid. The amount of sulfuric acid (as 100% H2SO is 1—1.5 times as much by weight as the sulfamic acid product. This by-product also contains ammonium salts and is therefore normally used as raw material for fertilizer (see Fertilizers). 

Batch Stirred Tank H2SO /Oleum Aromatic Sulfonation Processes. Low molecular weight aromatic hydrocarbc... 

Sulfuric acid, H2SO4, the most important commercial sulfur compound (see Sulfuric acid and sulfur trioxide), and peroxymonosulfuric acid [7722-86-3] (Caro s acid), H2SO, are discussed elsewhere (see Peroxides and peroxide compounds, inorganic). The lower valent sulfur acids are not stable species at ordinary temperatures. Dithionous acid [15959-26-9] H2S2O4, sulfoxyHc acid [20196-46-7] H2SO2, and thiosulfuric acid [13686-28-7] H2S2O2 are unstable species. A discussion of efforts to isolate and characterize the unstable sulfur acids is given (330). 

In Germany and France the Baumii scale is calculated using 144.3 as the constant. The Baumii scale only includes the sulfuric acid concentration range of 0—93.19% H2SO. Higher concentrations are not included in the Baumh scale because density is not a unique function of concentration between 93% and 100% acid. The density of sulfuric acid versus temperature and concentration is shown in Figure 4 (50). 

Figures 5 and 6 present the electrical conductivity of sulfuric acid solutions (51,52). For sulfuric acid solutions in the 90—100% H2SO concentration range, the electrical conductivity measurements reported by Reference 52 are beheved to be the best values other conductivity data are also available...

In most ores, sufficient Fe is already present. For some ores, it is necessary to add metallic iron. In practice, the oxidation potential of the solution can be monitored and controlled using the Fe /Fe ratio. Very high leaching efficiencies with H2SO ate common, eg, 95—98% dissolution yield of uranium (39). If acid consumption exceeds 68 kg/1 of ore treated, alkaline leaching is preferred. The comparative costs of acid, sodium hydroxide, and sodium carbonate differ widely in different areas and are the determining factor. 

Phosphates. The primary constituent of phosphate rock is fluorapatite, Ca3FP2022- Industrial phosphates including phosphate fertilizers (qv), phosphoric acid, and calcium phosphates (11) (see Phosphoric acid and the phosphates) are obtained from the large deposits of fluorapatite found in Florida in the United States, and in Morocco. Because phosphate rock is too insoluble to be useful as a fertilizer, it is converted to superphosphate [12431 -88-8] Ca(H2P0 2 CaSO, by H2SO and to triple superphosphate [7758-23-8] by H PO (l )- Phosphoric acid may also be... 

The final ceU product contains 250—300 g/L H2SO in the last stages of electrolyte purification, and antimony and bismuth precipitate, resulting in heavily contaminated cathodes that are recycled through the smelter. Arsenic and hydrogen evolved at the cathodes at these later stages react to form arsine, and hoods must be provided to collect the toxic gas. 

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