Sodium sulfite dried

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. 

Dried sodium sulfite Antioxidant, buffering agent, preservative, stabilizer iv, im, sc... 

BP Sodium sulphite anhydrous JP Dried sodium sulfite PhEur Nattii sulfis anhydricus USPNF Sodium sulfite anhydrous... 

Plants eqnipped with continuous sulfur dioxide absorption towers can produce sodium sulfite solution that can be used for this process step. A sodium sulfite supply system (see Figure 11.10) is provided to store the sodium sulfite solution. An optional sulfite dissolver tank may be provided for dissolving dry sodium sulfite with water in case additional sodium sulfite may be required. Sodium sulfite solution is injected into the methanol/water condensate solution before injecting into the condensate surge tank inlet (see Figure 11.11) so that it thoroughly mixes into the solution. This ensures that the solution in the tank is free of peroxides and safe for tanporary storage of the condensate solntion. 

The sodium sulfite precipitates first and is removed by centrifugation, washed with water, and dried. The mother Hquor containing ammonium chloride is sent to crystallising tanks and the salt thus formed is washed and dried, giving a product said to analyse weU over 99%. 

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). 

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). 

Shipment and Storage. Anhydrous sodium sulfite is suppHed in 22.7- and 45.4-kg moistureproof paper bags or 45.4- and 159-kg fiber dmms. Most sodium sulfite is shipped by rail in hopper cars. Sodium sulfite should be protected from moisture during storage. When dry it is quite stable, but when wet it is oxidized by air. 

Manufacture. Aqueous sodium hydroxide, sodium bicarbonate, sodium carbonate, or sodium sulfite solution are treated with sulfur dioxide to produce sodium metabisulfite solution. In one operation, the mother Hquor from the previous batch is reinforced with additional sodium carbonate, which need not be totally in solution, and then is treated with sulfur dioxide (341,342). In some plants, the reaction is conducted in a series of two or more stainless steel vessels or columns in which the sulfur dioxide is passed countercurrent to the alkaH. The solution is cooled and the sodium metabisulfite is removed by centrifuging or filtration. Rapid drying, eg, in a stream-heated shelf dryer or a flash dryer, avoids excessive decomposition or oxidation to which moist sodium metabisulfite is susceptible. 

Sodium sulfite [7757-83-7] M 126.0, d 2.63. Crystd from warm water (0.5mL/g) by cooling to 0°. Purified by repeated crystns from deoxygenated water inside a glove-box, finally drying under vacuum. [Rhee and Dasgupta J Phys Chem 89 1799 1985.]... 

Sodium carbonate reacts with sulfur oxides in a dry scrubber to form sodium sulfite and CO2. Sodium sulfite is then removed with a baghouse. 

A detailed procedure for the use of MCPBA recently appeared in Reagents for Organic Synthesis by Fieser and Fieser. The commercially available MCPBA (Aldrich) is 85% pure the contaminant, m-chlorobenzoic acid, can be removed by washing with a phosphate buffer of pH 7.5. The epoxidation is usually performed as follows a solution of 3 -acetoxy-5a-androst-16-ene (2.06 g, 6.53 mmoles) in 25 ml of chloroform (or methylene dichloride) is chilled to 0° in a flask fitted with a condenser and drierite tube and treated with a solution of commercial MCPBA (1.74 g, 20% excess) in 25 ml chloroform precooled to the same temperature. The mixture is stirred and allowed to warm to room temperature. After 23 hr (or until TLC shows reaction is complete) the solution is diluted with 100 ml chloroform and washed in sequence with 100 ml of 10% sodium sulfite or sodium iodide followed by sodium thiosulfate, 200 ml of 1 M sodium bicarbonate and 200 ml water. The chloroform extract is dried (MgS04) and evaporated in vacuo to a volume of ca. 10 ml. Addition of methanol (10 ml) followed by cooling of the mixture to —10° yields 0.8 gof 16a,17a-epoxide mp 109.5-110°. Additional product can be obtained by concentration of the mother liquor (total yield 80-90%). 

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 ... 

Neither the reaction to the intermediate maleic acid monoester nor the subsequent sulfation to the sulfosuccinic acid monoester sodium salt is fully complete (Scheme 2). Around 80% of the solid material is estimated to be true sulfosuccinate. Whether the unreacted material or possible side products are beneficial to the finished product has not yet been evaluated. Due to the necessity of dissolving the sodium sulfite (or bisulfite) in water, the product obtained is not normally more highly concentrated than 40% active matter. The consistency of the material varies from clear, low viscous liquids to pastes. Some substance can be spray-dried to obtain concentrated powders. 

Scheme 1 Synthetic steps for compounds 1 and 2.1 2-chloroacetic acid, 2 M aq. Na2C03, 80 °C, 20h, yield 51% 11 acetic anhydride, anhydrous sodiiun acetate, 60 °C, 5h, yield 65% 111 sodium sulfite, H2O, 90 °C, 4h, yield 82% IV toluene/piperidines, reflux 4h, yield 61% V tert-butyl acrylate, tri-(0-tolyl)phosphine, Pd(OAc)2, EtsN, DMF, reflux, yield 70-91% VI H2, 10% Pd/C, rt, yield 96-100% Vll TFA, DCM, rt, yield 75-100% Vlll (a) isobutylchloroformate, EtsN, dry DCM, 0°C, (b) R2NH, DCM, rt, 62-70% IX UAIH4, dry THF, yield 24-44% [11]...

Sodium hydrosulfite is produced through the Formate process where sodium formate solution, sodium hydroxide, and liquid sulfur dioxide reacted in the presence of a recycled stream of methanol solvent. Other products are sodium sulfite, sodium bicarbonate, and carbon monoxide. In the reactor, sodium hydrosulfite is precipitated to form a slurry of sodium hydrosulfite in the solution of methanol, methyl formate, and other coproducts. The mixture is sent to a pressurized filter system to recover sodium hydrosulfite crystals that are dried in a steam-heated rotary drier before being packaged. Heat supply in this process is highly monitored in order not to decompose sodium hydrosulfite to sulfite. Purging is periodically carried out on the recycle stream, particularly those involving methanol, to avoid excessive buildup of impurities. Also, vaporized methanol from the drying process and liquors from the filtration process are recycled to the solvent recovery system to improve the efficiency of the plant. 

The submitter used commercial cuprous bromide. The checkers prepared cuprous bromide by dissolving 600 g. (2.4 moles) of commercial copper sulfate crystals and 350 g. (3.4 moles) of sodium bromide in 2 1. of warm water the solution was stirred while 151 g. (1.2 moles) of solid sodium sulfite was added over a period of 10 minutes. Occasionally a little more sodium sulfite was required to discharge the blue color. The mixture was cooled, and the solid collected on an 8-in. Buchner funnel, washed once with water, pressed nearly dry, and then dried in... 

A. Coumarin dibromide. In a 1-1. three-necked flask, equipped with a mechanical stirrer, dropping funnel, and condenser fitted with a trap for hydrogen bromide, are placed 146 g. (1 mole) of coumarin and 200 ml. of chloroform. A solution of 160 g. (1 mole) of bromine in 85 ml. of chloroform is added drop-wise to the well-stirred solution of coumarin at room temperature over a period of 3 hours (Note 1). Excess bromine is removed by adding approximately 200 ml. of a 20% solution of sodium sulfite through the dropping funnel. The colorless chloroform layer is separated, washed with two 200-ml. portions of water, and dried over magnesium sulfate (Note 2). After the mixture has stood for only a few minutes (Note 3), the magnesium sulfate is removed by filtration and the solution of the dibromide... 

After completion of the reaction, saturated aqueous sodium sulfite solution (10 mL) was added and the mixture stirred for 15 minutes. Ethyl acetate (5 mL) was added and the two phases were separated. The aqueous layer was extracted with ethyl acetate (3x5 mL). The combined organic extracts were washed with brine (20 mL), dried over magnesium sulfate, filtered and concentrated using a rotary evaporator to give the crude product. 

A solution of benzyl-4,6-0-isopropylidene-a-D-glucopyranoside, 2-deoxy-2-[[(2-hydroxy-3,5-di-tert-butylphenyl)methylene]imine] (0.03 mmol) in dichloromethane (1.5 mL) was added to a solution of [VO(acac)2] (0.02 mmol) in the same solvent (1.5 mL). After 10 min of stirring, thioanisole (Immol) was added followed by hydrogen peroxide (1.1 mmol). After 1 h, the addition of a saturated solution of sodium sulfite quenched the reaction. The organic phase was filtered through a bed of Celite contained in a Pasteur pipette, dried over sodium sulfate and evaporated under vacuum to afford the reaction products (Table 9.6). 

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