Sodium percarbonate oxidation

There are international transport regulations controlling the transport of sodium percarbonate, which assigned it to Class 5.1, oxidizing substances, however, no such compound has ever been commercialized, and sodium carbonate peroxohydrate is treated as nonhazardous. The origin of this item is not known. 

The influence of substituents on the rates of degradation of arylazo reactive dyes based on H acid, caused by the action of hydrogen peroxide in aqueous solution and on cellulose, has been investigated [43]. The results suggested that the oxidative mechanism involves attack of the dissociated form of the o-hydroxyazo grouping by the perhydroxyl radical ion [ OOH]. The mechanism of oxidation of sulphonated amino- and hydroxyarylazo dyes in sodium percarbonate solution at pH 10.6 and various temperatures has also been examined. The initial rate and apparent activation energy of these reactions were determined. The ketohydrazone form of such dyes is more susceptible to attack than the hydroxyazo tautomer [44]. 

The oxidation of alcohols by sodium percarbonate is also promoted by the addition of molybdenyl acetoacetate [5] and yields are comparable with those obtained by the chromate mediated reactions. 

Molybdenum-catalysed oxidation of alcohols by sodium percarbonate (Table 10.20)... 

The oxidation procedure is amenable to a number of modifications. The solvent used may be varied carbon tetrachloride, hexane, toluene and dichloro-methane have all been used successfully, although the latter two are the solvents of choice. The most common oxidant is aqueous hydrogen peroxide, but other oxidants such as t-butyl hydroperoxide [4], sodium perborate (Table 1, Entries 18 and 22) and sodium percarbonate [4] have also been employed. It is interesting to note the effect of a change of oxidant. Using alkaline hydrogen peroxide... 

The formation of peracids as the effective oxidizing species has often been proposed for oxidations with sodium percarbonate in the presence of organic acids or acid anhydrides30-32. It was observed that at room temperature and in dichloromethane as solvent, the addition of acetic anhydride induced the epoxidation by sodium perborate of mono-, di- and trisubstituted alkenes, including a,/i-unsaturated ketones in a slightly exothermic reaction33 (equation 6). 

Vinyl boronates 228 undergo 1,3-dipolar cycloaddition with aryl hydroximinoyl chloride 229 to furnish the imine-oxide 231. The boronate moiety is highly labile under the reaction conditions and it undergoes protonolysis to yield isoxazolines 232. Alternatively, the boronates could be oxidized with hydroperoxides or sodium percarbonate to furnish the 4-hydroxyisoxazolines 233 in good yield (Scheme 39) <2000T965>. 

Allen, J. V., Drauz, K. H., Flood, R. W., Roberts, S. M. and Skidmore, J. Polyamino acid-catalysed asymmetric epoxidation sodium percarbonate as a source of base and oxidant. Tetrahedron Lett., 1999, 40, 5417-5420. 

Sodium percarbonate (PCS) can also be employed for the oxidation of sulfides to sulfones in acetonitrile assisted by ultrasound.415... 

Peroxygens are used widely throughout industry for the safe and effective treatment of cyanide in process and waste waters. Under alkaline conditions, cyanide is efficiently oxidized to the much less toxic cyanate by peroxygens such as hydrogen peroxide, Caro s acid and sodium percarbonate.27 The cyanate slowly hydrolyses to ammonia and bicarbonate (Figure 5.5). 

Sodium percarbonate, Na2C206.—The percarbonate is said4 to be formed by the electrolytic oxidation of the normal carbonate, but it has not been isolated by this method. A substance of the formula 2Na2COs,3H2Oa is obtained by the interaction of 3 molecules of hydrogen peroxide in aqueous solution and 2 molecules of sodium carbonate, the product being subsequently dried in vacuo Other percarbon-ates have been described,8 but their existence is still a subject of debate. 

Sodium perborate has been recommended for the oxidation of alkenyldialkoxyboranes to aldehydes. In particular, the reagent avoids the formation of possibly hazardous 2 1 aldehyde-4iydrogen peroxide adducts as well as C—C bond cleavage. Sodium percarbonate is an air-stable solid, inexpensive and self-buffered, that appears to be a promising oxidant. ... 

Oxidizing agents such as sodium perborate and sodium percarbonate have also been used in cleaning contact lenses. None of these products are currently marketed for that purpose in the United States. Products marketed earlier were withdrawn because of their deleterious effects on lens polymers. 

Practically all leuco compounds of vat dyes will oxidize on exposure to air but the reaction often takes 30 to 45 minutes to complete. When the goods are in an open state and air has access to every part, atmospheric oxidation does not present much difficulty. When the material is in a dense mass such as a tightly-wound roll or a cheese or cone of yarn, the penetration of air to the innermost portions may be slow and in such cases treatment with an oxidizing agent is of assistance. The goods can be rinsed with cold water and then treated for 10 to 20 minutes at 30° to 40°C (86° to 104°F) in a liquor containing 1 to 2 parts per 1000 of potassium dichromate and 2 5 to 10 parts of 30 per cent acetic acid. More frequently the oxidation is carried out at 40° to 50°C (104° to 122°F) in a solution containing 3 parts of sodium percarbonate or 2 parts of sodium perborate per 1000, followed by a rinse and treatment with dilute acetic acid (6 to 10 parts of 30 per cent acid per 1000) to neutralize the alkali derived from the per-salt. 

The dyes are vatted in the usual way and added to the dyebath, which is then adjusted to pH 10 by the addition of sodium bicarbonate, and the dyeing is carried out at 95°C (203°F). Oxidation of the pigment requires treatment with sodium percarbonate or perborate at 95°C (203°F) because the action of atmospheric oxygen is slow. The vat dyes offer an opportunity to dye a limited range of shades of excellent all-round fastness. 

Several other oxidizing agents can be made from hydrogen peroxide and thus be derived indirectly from oxygen. These include sodium perborate, sodium percarbonate, urea peroxide, peracids, potassium peroxymonosulfate, amine oxides, dioxiranes, and iodosobenzene (4.24). 

The Haloform reaction is catalyzed by cyclodextrins in what the authors label as inverse phase transfer catalysis, 25 but the synthetic utility of this variation remains to be seen. An alternative to the use of halogen is a nitroarene catalyzed oxidation of acetophenone with sodium percarbonate or sodium perborate.26 However, the yields of substituted benzoic acids furnished by this method are mediocre (23-73%) in comparison to the conventional Haloform conditions. Likewise, the Haloform reaction of acetone with iodine in liquid ammonia is without synthetic merit (8-12%).27... 

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