Sodium persulphate production

Sodium m-nitrobenzenesulphonate has been proposed as an oxidising agent for vat dyes. It is available as a proprietary product and is claimed to react with leuco compounds more quickly than does peroxide. The solubilised vat leuco esters are most commonly hydrolysed and reoxidised to the insoluble parent dye using sodium nitrite and sulphuric acid. Alternative oxidising agents for vat leuco esters include hydrogen peroxide and ammonium metavanadate (NH4VO3), persulphates and nitric acid [218]. 

Potassium persulphate (42.0 g, 0.156 mol) is added at 10 °C over 40 minutes to a solution of o-iodobenzoic acid (20.0 g, 0.0807 mol) in 80 ml of concentrated sulphuric acid, and the mixture is kept at this temperature for an additional 20 minutes. Benzene (75 ml) (CAUTION) is added, and the mixture is stirred for 3 hours at 25 °C and then poured on to ice. A small amount of 2-carboxydiphenyliodonium bisulphate is collected. The addition of 40 g of potassium iodide in a minimum of water precipitates the iodonium iodide. The salts are combined and stirred with 200 ml of 5 m sodium hydroxide, and the product (DPIC) is collected and washed with water. Recrystallisation from c. 350 ml of water gives 20.1 g (77%) of DPIC as coarse prisms (not hydrated), m.p. 223-225 °C. 

With sodium peroxide ammonium persulphate reacts energetically, with production of incandescence and smoke 1... 

Autoxidation of colupulone gives a similar mixture of products to that obtained by oxidation with sodium or ammonium persulphate. A major product is the dihydrofuran (48) in which one of the isoprenyl side chains is oxidized and cyclized. In other products (49)-(53) alternative cyclizations to furan or pyran rings occur [43]. Japanese workers have described a series of oxidation products of lupulone of which the lupoxes contain one additional oxygen atom (CgeHggOo) and the lupdoxes two (C2eH380e). Colupox a is identical with the dihydrofuran (48) but the identity of the other products has not been confirmed. 

Details are given of the preparation of SAN latexes by micro-emulsion polymerisation using sodium dodecyl sulphate as an anionic surfactant. Kinetics of copolymerisation was studied at different temperatures using different concentrations of potassium persulphate and hydrogen peroxide/ascorbic acid. The latexes were characterised for particle size and number of particles by dynamic light scattering and TEM. Products were examined using NMR and thermal analysis. 20 refs. INDIA... 

Commercial polymerizations are typically carried out in jacketed glass-lined kettles at about 40 C using potassium persulphate as initiator with the emulsifier being formed in situ using rosin, aqueous caustic soda and the sodium salt of a naphthalene sulphonic acid-formaldehyde condensation product. Monomer conversion is followed by measuring the specific gravity of the emulsion. In the case of sulphur-modified polychloroprenes polymerization may be... 

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