Sulfite, sodium, reduction

The sulfonic acids of these metallocenes can be converted to sulfonyl chlorides, sulfonamides, etc., by appropriate reagents. Reduction of ferrocene-sulfonyl chloride by lithium aluminum hydride produces the rapidly oxidized ferrocenethiol in quantitative yield (43). Both the sulfonic acid of cyclopentadienylmanganese tricarbonyl and the corresponding sulfinic acid (obtained by sodium sulfite reduction of the sulfonic acid) have been converted to sulfones (10). 

Stannous chloride or sodium sulfite reduction to the hydrazine from which the hydrocarbon is obtained by oxidation.7... 

Bromate and iodate salts are prepared on a much smaller scale than chlorates. Under appropriate conditions, these ions undergo oscillating chemical reactions known as chemical clocks. The best known clock reaction is observed when an acidified solution of sodium sulfite (Na2S03) is mixed with an excess of iodate in the presence of starch indicator. After a suitable induction period allowing for sodium sulfite reduction of iodate to iodide [Eq. (44)], the blue, starch-iodine color periodically appears and disappears as the iodide is oxidized to iodine [Eq. (45)], and the iodine is reduced back to iodide [Eq. (46)]. 

The most important manganese(V) compound is K MnO, a key intermediate in the manufacture of potassium permanganate. Potassium manganate(V) is an easily crystallized salt obtained by reduction of potassium permanganate using sodium sulfite in strong sodium hydroxide solution. This was the first compound to be recognized as exclusively pentavalent. 

The reduction of alkyl-substituted siUcon and tin peroxides with sodium sulfite and triphenylphosphine has been reported (33,93). Alkyl-substituted aluminum, boron, cadmium, germanium, siUcon, and tin peroxides undergo oxygen-to-metal rearrangements (33,43,94), eg, equations 22 and 23. 

Chemical Properties. Anhydrous sodium sulfite is stable in dry air at ambient temperatures or at 100°C, but in moist air it undergoes rapid oxidation to sodium sulfate [7757-82-6]. On heating to 600°C, sodium sulfite disproportionates to sodium sulfate and sodium sulfide [1313-82-2]. Above 900°C, the decomposition products are sodium oxide and sulfur dioxide. At 600°C, it forms sodium sulfide upon reduction with carbon (332). 

Water Treatment. Sodium sulfite is an agent in the reduction of chlorine or oxygen in water. Dissolved oxygen in boiler water tends to enhance pitting and other types of corrosion. In boilers operated at below 4.82 MPa (700 psi), a residual concentration of 30 ppm of sodium sulfite is generally effective. Catalytic amounts of cobalt are often added to accelerate the reaction of oxygen with sulfite (321,322) (see Water, industrial water treatment). 

In removing excess free chlorine from municipal or industrial water and from wastewater, sodium sulfite competes with bisulfite or sulfur dioxide. Other commercial appHcations of sodium sulfite in wastewater treatment include the reduction of hexavalent chromium to the less toxic Cr " salts as well as the precipitation of silver and mercury. 

Arylalkylsulfones ate important intermediates obtained by alkylation of arylsulfinic acids. The latter ate obtained by reduction of the corresponding sulfonyl chloride. This reduction process is simple and of general appHcation involving the addition of the isolated sulfonyl chloride paste to excess aqueous sodium sulfite followed by salting-out the product and isolation. With mote rigorous reduction conditions, such as zinc/acid, sulfonyl chlorides ate reduced through to aryknercaptans, eg, 2-mercaptonaphthalene is manufactured from naphthalene-2-sulfonyl chloride. 

The removal of each milligram of oxygen requires about 8 mg of sodium sulfite, so that the dose should be adjusted to suit the amount of oxygen introduced, which corresponds roughly to 80mg/l of cold make-up. A high level of condensate return therefore reduces the scavenger demand, and this is not only an economy in itself but can also mean a considerable reduction in the amount of total dissolved solids introduced into the boiler with the feedwater. 

Where water softening is provided and there is no reduction in system water TDS, treatments are primarily based on inorganic corrosion inhibitor blends (nitrite, molybdate, etc.). Under these circumstances, there is no benefit in using an expensive organic oxygen scavenger to keep the TDS level low, and a common chemical such as catalyzed sodium sulfite may be used. 

Where dry, catalyzed sodium sulfite is used as the scavenger source, the provision of 2 to 3% metabisulfite into the day-tank batch provides sufficient pH level reduction to ensure the cobalt catalyst does not precipitate. The overall oxygen scavenging reaction is as follows ... 

Other methods have been developed for the removal of oxygen (particularly from flowing streams). These include the use of electrochemical or chemical (zinc) scrubbers, nitrogen-activated nebulizers, and chemical reduction (by addition of sodium sulfite or ascorbic acid). Alternately, it may be useful to employ voltam-... 

Sulfinic acids can be prepared by reduction of sulfonyl chlorides. Though mostly done on aromatic sulfonyl chlorides, the reaction has also been applied to alkyl compounds. Besides zinc, sodium sulfite, hydrazine, sodium sulfide, and other reducing agents have been used. For reduction of sulfonyl chlorides to thiols, see 19-57. 

CuCl, especially in a single crystal form, is extensively used as an optical material for its special optical properties. Orel et al. [2] first proposed a new method to obtain CuCl particles by the reduction of Cu with ascorbic acid. Several dispersants were used in the reduction and monodispersed CuCl particles can be obtained by selecting the proper dispersant and reduction conditions. In this work, the above method was used to modify the traditional process of CuCl preparation, namely, by reducing the Cu " with sodium sulfite to obtain the highly active CuCl catalyst to be used in the direct process of methylchlorosilane synthesis. 

Arenesulfinate esters are usually prepared from an arenesulfinyl chloride and an alcohol in ether and pyridine. The arenesulfinyl chloride is usually prepared from the sodium arenesulfinate which is made by reduction of the arenesulfonyl chloride, preferably by aqueous sodium sulfite. After the crystalline sulfinate epimer has been removed by filtration, the equilibrium between the epimers remaining in the mother liquor may be reestablished by the addition of hydrogen chloride as shown by Herbrandson and Cusano . In this way the yield of the least soluble diastereomer may be increased beyond that which exists in the original reaction mixture (Scheme 1). Solladie prepared sulfinate ester 19 in 90% yield using this technique and published the details of his procedure. Estep and Tavares also published a convenient recipe for this method, although their yields were somewhat lower than Solladie s. 

The most commonly employed routes for the preparation of the / -sulfatoethylsulfone group, which is the essential structural feature of vinylsulfone reactive dyes, are illustrated in Scheme 8.5. One method of synthesis involves, initially, the reduction of an aromatic sulfonyl chloride, for example with sodium sulfite, to the corresponding sulfinic acid. Subsequent condensation with either 2-chloroethanol or ethylene oxide gives the / -hydroxyethylsulfone, which is converted into its sulfate ester by treatment with concentrated sulfuric acid at 20 30 °C. An alternative route involves treatment of an aromatic thiol with 2-chloroethanol or ethylene oxide to give the /Miydroxyethylsulfonyl compound which may then be converted by oxidation into the /Miydroxyethylsulfone. 

The most feasible method consists in the reduction of diazonium salts with sodium sulfite. Although this method is given in several laboratory manuals, the results were not found entirely satisfactory. The present directions provide for a lengthy but essential heating of the diazonium-sulfite mixture, omit the useless zinc dust reduction, and supply exact details for preparation on a fairly large laboratory scale. 

Toluenesulfinic acid and its salts have been prepared by three general methods (1) The reduction of the sulfonyl chloride. The reagents which have been used for this arc sodium amalgam,1 zinc dust in alcohol or water,2 sodium sulfite,3 sodium sulfide,4 potassium hydrosulfide 5 (the thio acid being first formed) and sodium arsenite.6 (2) From toluene by the Friedel and Crafts reaction, using either sulfur dioxide and hydrogen chloride 7 or sulfuryl chloride.8 (3) From -toluidine by diazotization and... 

Most published directions for the preparation of phenylhydrazine specify the use of zinc dust and acetic acid following the reduction with sodium sulfite. No improvement in the quality or quantity of the product was obtained by using zinc and acetic acid. 

It is best to use freshly prepared sodium sulfite for the reduction, since the commercial quality is poor and gives a lower yield of phenylhydrazine. A cylinder of liquid sulfur dioxide should, of course, be available. 

More abundant are reductions with sodium sulfite which is applied in aqueous solutions (solubility 24%). Its specialties are reduction of peroxides to alcohols [257], of sulfonyl chlorides to sulfinic acids [252], of aromatic diazonium compounds to hydrazines [253], and partial reduction of geminal polyhalides [254] Procedure 43, p. 216). 

Geminal dihalides undergo partial or total reduction. The latter can be achieved by catalytic hydrogenation over platinum oxide [512], palladium [512] or Raney nickel [63, 512], Both partial and total reduction can be accomplished with lithium aluminum hydride [513], with sodium bis(2-meth-oxyethoxy)aluminum hydride [514], with tributylstannane [503, 514], electro-lytically [515], with sodium in alcohol [516] and with chromous sulfate [193, 197]. For partial reduction only, sodium arsenite [220] or sodium sulfite [254] are used. 

Conversion of diazonium salts to hydrazines was achieved by reduction with zinc in acidic medium (yields 85-90%) [59<5], with stannous chloride (yield 70%) [184, and sodium sulfite (yields 70-80%) [253,597]. Nitro groups present in the diazonium salts survive the reduction unharmed [184,253],... 

More reliable reagents for the preparation of sulfinic acids are zinc [694, 695], sodium sulfide [249] and sodium sulfite [2S2. These reagents not only stop the reduction at the stage of the sulfinic acids (in the form of their salts) but do not reduce other functions present in the molecules. In the reduction of anthraquinone-l,5-disulfonyl chloride with sodium sulfide below 40° anthraquinone-l,5-disulfinic acid was obtained in 83.5% yield [249], and p-cyanobenzenesulfonyl chloride was reduced to p-cyanobenzenesulfinic acid in 87.4% yield [252]. 

REDUCTION WITH SODIUM SULFITE Partial Reduction of Geminal Polyhalides [25 ... 

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