Peroxodisulfate salts

The principal use of the peroxodisulfate salts is as initiators (qv) for olefin polymerisation in aqueous systems, particularly for the manufacture of polyacrylonitrile and its copolymers (see Acrylonitrile polymers). These salts are used in the emulsion polymerisation of vinyl chloride, styrene—butadiene, vinyl acetate, neoprene, and acryhc esters (see Acrylic ester polymers Styrene Vinyl polymers). 

Because the peroxodisulfate salts are all made electrochemicaHy, the electrical energy cost is a significant part of thek manufacturing cost. The 1994 world capacity for peroxodisulfate salts was about 75,000 metric tons, valued at about 30 x 10 . The principal appHcations are in polymerization catalysis and the market broadly tracks the plastics business. The Caro s acid business is difficult to quantify because the product itself is not commercial but made on-site from purchased hydrogen peroxide. 

Peroxide titanate complexes, 25 98 Peroxide value, 20 827 in soap making, 22 736 Peroxidic compounds, 25 42 Peroxoborates, names, CAS numbers, and IUPAC names of, 18 398t Peroxocarbonates, 28 401 Peroxo compounds, 28 392-393, 397 Peroxodisulfate ion, 28 408 Peroxodisulfates, 28 392, 408-410 Peroxodisulfate salts, 28 418 uses for, 28 408-409 Peroxodisulfuric acid, 28 407 408 Peroxohydrate(s), 24 40 28 411—415 of melamine, 28 415 stabilization of, 28 413 Peroxo molybdate complexes, 2 7 22 Peroxomonophosphate ion, 28 403 Peroxomonophosphoric acid, 28 403 Peroxomonosulfates, 28 406 407... 

In addition to CuCfi, some other compounds such as Cu(OAc)2, Cu(N03)2-FeCl.i, dichromate, HNO3, potassium peroxodisulfate, and Mn02 are used as oxidants of Pd(0). Also heteropoly acid salts comtaining P, Mo, V, Si, and Ge are used with PdS04 as the redox system[2]. Organic oxidants such as benzo-quinone (BQ), hydrogen peroxide and some organic peroxides are used for oxidation. Alkyl nitrites are unique oxidants which are used in some industrial... 

Acetoxybenzene is prepared by the reaction of benzene with Pd(OAc)2[325,342-345], This reaction is regarded as a potentially useful method for phenol production from benzene, if carried out with only a catalytic amount of Pd(OAc)2. Extensive studies have been carried out on this reaction in order to achieve a high catalytic turnover. In addition to oxygen and Cu(II) salts, other oxidants, such as HNOi, nitrate[346,347], potassium peroxodisulfate[348], and heteropoly acids[349,3S0], are used. HNO is said to... 

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

Peroxodisulfates. The salts of peroxodisulfuric acid are commonly called persulfates, three of which are made on a commercial scale ammonium peroxodisulfate [7727-54-0] (NH4)2S20g potassium peroxodisulfate [7727-21-1] K2S20g and sodium peroxodisulfate [7775-27-1] Na2S20g. The peroxodisulfates are all colorless, crystalline soHds, stable under dry conditions at ambient temperature but unstable above 60°C. 

The peroxodisulfates are made commercially by Akkim (Turkey), Degussa (Germany), PMC, Migas, Peroxid-Chemie, ERB Engineering (India), Sangen (Taiwan), and TokaiDenka (Japan). In 1994 the U.S. price of the sodium salt was 1.92/kg, the potassium salt 2.07/kg, and the ammonium salt 1.68/kg. 

Peroxodisulfuric acid, H2S2O8, is a colourless solid mp 65° (with decomposition). The acid is soluble in water in all proportions and its most important salts, (NH4)2S208 and K2S2O8, are also freely soluble. These salts are, in fact, easier to prepare than the acid and both are made on an industrial scale by anodic oxidation of the corresponding sulfates under carefully controlled conditions (high current density, T < 30°, bright Pt electrodes, protected cathode). The structure of the peroxo-disulfate ion [now preferably called hexaoxo-/r-peroxodisulfate(2-)]0 l is OaSOOSOa " with... 

When aqueous solutions of the polymerisation initiators 2,2/-azobis(2-amidinio-propane) chloride and sodium peroxodisulfate are mixed, the title compound separates as a water insoluble shock-sensitive salt. The shock-sensitivity increases as the moisture level decreases, and is comparable with that of lead azide. Stringent measures should be used to prevent contact of the solutions outside the polymerisation environment. (The instability derives from the high nitrogen (21.4%) and oxygen (31.6%) contents, and substantial oxygen balance, as well as the structural factors present in the salt.)... 

The salt exploded dining drying, but no cause was determined. However, the reputed explosive character of tetraamminezinc peroxodisulfate, possibly formed from interaction of the ammonium salt, galvanised iron and ammonia, was mentioned as a possible cause. 

See Tetraamminezinc peroxodisulfate See other oxidants, peroxoacid salts... 

Azobis(2-amidiniopropane) chloride See 2,2/-Azobis(amidiniopropane) peroxodisulfate See other PEROXOACID SALTS, OXIDANTS... 

Activation volumes for peroxodisulfate oxidation of [Fe(bipy)2(CN)2] and of [Fe(diimine)(CN)4] with diimine = bipy, phen, Mc2bsb, ein (HN=CHCH=NH) show a large ligand effect, 4-5 for [Fe(ein)(CN)4] to —10 cm moD for [Fe(Mc2bsb)(CN)4]. This reflects the big difference in solvation properties, from hydrophilic ein to strongly hydrophobic Mc2bsb. There is a moderately good correlation between AV and AS for peroxodisulfate oxidation of the sequence of complexes [Fe(diimine)3] , [Fe(diimine)2(CN)2], [Fe(diimine)(CN)4], and [Fe(CN)6]" (diimine = bipy or phen). Salt effects ([salt] up to 6 moldm ) on have been established for peroxodisulfate oxidation of this sequence of complexes for bipy as diimine. ... 

Ammonium peroxodisulfate is more soluble in water than the potassium salt furthermore, it dissolves in more polar organic solvents (e.g., DMF), so that it is sometimes also used for initiating polymerizations in organic media. In polymerizations initiated by peroxodisulfates the reaction medium is liable to become acidic, so that buffering is generally necessary (see Example 3-2). 

In general, peroxomonosulfates have fewer uses in organic chemistry Uian peroxodisulfates. However, the triple salt is used for oxidizing ketones to dioxiianes, which in turn me useful oxidants in oiganic chemistry... 

The most commonly used water-soluble initiator is the potassium, ammonium, or sodium salt of peroxodisulfates. Redox initiators (Fe2+salt/peroxodisul-fate, etc.) are used for polymerization at low temperatures. Oil-soluble initiators, such as azo compounds, benzoyl peroxides, etc., are also used in emulsion polymerization. They are, however, less efficient than water-soluble peroxodisulfates. This results from the immobilization of oil-soluble initiator in polymer matrix, the cage effect, the induced decomposition of initiator in the particle interior, and the deactivation of radicals during des orption/re-entry events [14, 15]. 

The most intensive bleaching action is achieved with paste bleaches, which are prepared before use by mixing hydrogen peroxide solution (6-12 vol%) with a bleach powder. The powder consists of a peroxodisulfate, an alkalizing agent, stabilizers, thickeners, and other additives. Sodium, potassium, or ammonium peroxodisulfate is used. The ammonium salt is most effective when combined with an alkalizing component such as sodium carbonate or silicate, ammonia is formed. 

Barton et al. [232] conducted the emulsion polymerization of the sparingly water-soluble monomer St and of the fairly water-soluble monomer MMA in the presence and absence of the water-soluble inhibitor, potassium nitrosodi-sulfonate (Fremy s salt). By using oil-soluble dibenzoyl peroxide (DBP) and water-soluble ammonium peroxodisulfate (APS) as the free-radical initiators, they examined the effect of the location of the initiator on the kinetics of these emulsion polymerizations with SDS as the emulsifier. Figure 7 shows an example of the experimental results. 

When the emulsion polymerization of St was carried out in the presence of Fremy s salt and ammonium peroxodisulfate in the aqueous phase, a distinct... 

SUver(n) forms stable complexes with a variety of nitrogen donor ligands such as pyridine, substituted bipyridine, phenanthrohne, or citrazinic acid. They are usually obtained by reaction of a silver(I) salt with peroxodisulfate in the presence of the ligand. ... 

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