Sodium pyrosulfite,

Various processes have been disclosed wherein moist soHd sodium pyrosulfite [7681-57-4] is stirred in a steam-heated vessel with sodium carbonate. The exothermic reaction at 80—110°C results in the drying of the product. A lower grade of sodium sulfite is produced commercially in the United States as a by-product of the sulfonation—caustic cleavage route to resorcinol (333). 

Physical Properties. Sodium metabisulfite (sodium pyrosulfite, sodium bisulfite (a misnomer)), Na2S20, is a white granular or powdered salt (specific gravity 1.48) and is storable when kept dry and protected from air. In the presence of traces of water it develops an odor of sulfur dioxide and in moist air it decomposes with loss of part of its SO2 content and by oxidation to sodium sulfate. Dry sodium metabisulfite is more stable to oxidation than dry sodium sulfite. At low temperatures, sodium metabisulfite forms hydrates with 6 and 7 moles of water. The solubiHty of sodium metabisulfite in water is 39.5 wt % at 20°C, 41.6 wt % at 40°C, and 44.6 wt % at 60°C (340). Sodium metabisulfite is fairly soluble in glycerol and slightly soluble in alcohol. 

Ch nical Designations - Synonyms Sodium acid sulfite Sodium metebisulfite Sodium pyrosulfite Chemical Formula NaHS04-Na2S205. 

The aqueous solution of the disodlum salt of Lnitrogen atmosphere in the course of 30 minutes with stirring with a solution of 104 g of chloroacetic acid (1.1 mols) and 4 g of sodium pyrosulfite in 200 ml of water. 

Vitamins—fat soluble Whole amounts of Sorbita was mixed with PN-Twin no. 2 (2.2 L) Sodium citrate, sodium pyrosulfite, sodium thioglycollate, HCO-60, benzyl alcohol, polysorbate 80 Aminoethylsulfonic acid, sesame oil, soybean lecithin, D-sorbitol, concentrated glycerin 1,157.1 5.1... 

Sodium sulfite, [CAS 7757-83-7], NagSCL and sodium hydrogen sulfite, [CAS 7631-90-5], NaHSCU are formed by the reaction of sulfurous add and NaOH or sodium carbonate in the proper proportions and concentrations. Sodium sulfite, when dry and upon heating, yields sodium sulfate and sodium sulfide. Sodium pyrosulfite (sodium metabisulfite), [CAS 7681-57-4], is a common sulfite. Crystalline sulfites... 

S20 K2 Potassium pyrosulfite, 2 165, 166 %-hydrate, 2 165 S20sK2-4S03KH, 2 167 S203Na2 (and + 7H20) Sodium pyrosulfite, 2 162, 164, 165 S20 Ba-2H20 Barium dithionate, 2 170... 

Most of the sodium bisulfite of commerce is really the anhydride, Na2S205, sodium metabisulfite, or sodium pyrosulfite. Sodium bisulfite is not stable and is generally transported in the metabisulfite form, which is a solid containing 98 percent Na2S205, 1.5 percent Na2S03, and 0.5 percent Na2S04. 

A mixture of 7,7,9,9-tetramethyl-l,4-dioxa-8-aza-spiro [4.5] decan-8-oxyl (50 g) and 2-(4-ethylphenoxymethyl)oxrran (124.75 g) was heated to 60°C and then treated with of 0.32 g of copper(II) chloride dissolved in 1.6 ml of ethanol. This mixture was further treated with the dropwise addition of 70% aqueous t-butylhydroperoxide (45 g), reacted for 16 hours at 60°C, and cooled to ambient temperature. Excess t-butyUiydroperoxide was decomposed by the dropwise addition of 20% aqueous sodium pyrosulfite solution. The mixture was then treated with 100 ml of EtOAc, and the organic and aqueous phases were separated. The organic... 

SYNS DISODIUM DISULFITE DISODIUM PYROSULFITE DISULFUROUS ACID, DISODIUM SALT SODIUM DISULFITE SODIUM METABISULFITE SODIUM METABISULPHITE SODIUM PYROSULFITE... 

The function of the chelator is to complex the ferrous ion and thus limit the concentration of free iron. Redox systems appear very versatile, permitting polymerization at ambient temperatures and the possibility of control of the rate of radical initiation versus polymerization time. This would thus permit control of heal generation and the minimization of reaction time. The use of the redox system ammonium persulfate (2 mmol) together with sodium pyrosulfite (Na S Oj 2.5 mmol) together with copper sulfate (0.002 mmol) buffered with sodium bicarbonate in I liter of water form an effective redox system for vinyl acetate emulsion polymerization. The reaction was started at 25 C and run nonisothermally to 70 C. The time to almost complete conversion was 30 min (Warson, 1976 and Edelhauser, 1975). 

Cyanospiro[2-pyrazoline-5,l cyclopropane] 228 underwent unusual transformations into 3(5)-cyano-5(3)-(2-hydroperoxyethyl)pyrazoles 229 in the presence of atmospheric oxygen, and these were converted into (2-hydroxy-ethyOpyrazoles 230 with sodium pyrosulfite in aqueous methanol (Scheme 15) <2004RCB2257>. 

Disodium disulfite disodium pyrosulfite disulfurous acid, disodium salt E223 natrii disulfis sodium acid sulfite sodium pyrosulfite. 

Ethyl Mercaptan 7550-35-8 Lithium Bromide Sodium Pyrosulfite... 

Purification. The commercial solvent, made by addition of SOj to butadiene and hydrogenation, contains various contaminants. One method of purification is by passage through a column of Linde molecular sieves and fractionation. Another is by repeated vacuum distillation from sodium hydroxide pellets until a mixture of 1 ml. with 1 ml. of 100% sulfuric acid developes no color in 5 min. the solvent is then distilled again from calcium hydride. Another involves treatment with permanganate and sulfuric acid to remove oxidizable impurities, addition of enough sodium pyrosulfite to give a clear solution, extraction with methylene chloride, treatment with P Os, decantation, and distillation. 

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