CAS number：7757-83-7
molecular formula：Na2O3S
molecular weight：126.04
EINECS number：231-821-4

English synonyms

anhydroussodiumsulfite;disodiumsulfite;exsiccatedsodiumsulfite;natriisulphis;natriumsulfid;natriumsulfit;natriumsulfurosum;sodiumsulfite(2:1)

Related categories

Co sulfides and sulfates; inorganic chemical products; inorganic salts; bleaching agents; food additives; reference substances; intermediates; alkali sulfides; other biochemical reagents; organic chemical raw materials; other inorganic substances; biochemical reagents; denaturants; genomics and Molecular Diagnostics; Inorganic Compounds and Salts; Biochemistry; Pharmaceutical Raw Materials; Auxiliaries; Chemical Products-Organic Solvents; Chemical Products-Inorganic Chemicals; Sulfates; Chemicals; Sodium Sulfite; Anhydrous Sodium Sulfite; Auxiliaries; Chemical Products; Inorganic Acids; Pharmaceutical API;Antioxidants;Chemical Materials;Inorganic Chemicals;Inorganics;Water Ttreatment Chemicals;Essential Chemicals;Reagent Grade;Routine Reagents;Inorganic Salts;Synthetic Reagents;Disulfide Bridge Cleavage Reagents;AlphabeticalBiochemicals and Reagents;Biochemicals and Reagents;Denaturation;Disulfide Bridge Cleavage ReagentsSynthetic Reagents;ACS GradeBiochemicals and Reagents;Analytical Reagents for General Use;Puriss p.a.;Q-S, Puriss p.a.;inorganic compound;Paper, glass, printing and dyeing;general chemical raw materials;Chinese medicine reference substance;general analytical reagents;inorganic chemical raw materials ;Sodium;chemical raw materials;fine chemical raw materials;sulfates;inorganic substances;organic chemical industry;general biochemical reagents-inorganic salts;chemical reagents;

Introduction

Sodium sulfite is an inorganic compound. It is a white granular powder at room temperature with a sulfur dioxide odor, stable when dry and sensitive to moisture. Soluble in water and glycerol, insoluble in ethanol, the aqueous solution is alkaline, its aqueous solution is alkaline to litmus paper and phenolphthalein, and reacts with acid to produce toxic sulfur dioxide gas, the pH of 1% aqueous solution is 8.3~9.4, with strong reduction sex. When heated, it is decomposed into sodium sulfide and sodium sulfate, and it is gradually oxidized to sodium sulfate when placed in the air. In nature, it exists in three forms: anhydrous sodium sulfite, sodium sulfite heptahydrate and sodium sulfite decahydrate, among which anhydrous sodium sulfite is the least easily oxidized.

 Chemical properties

Colorless monoclinic crystal. Soluble in water, its aqueous solution is alkaline reaction; insoluble in ethanol.

Use

●  Used in rayon stabilizer, fabric bleaching agent, photographic developer, dyeing and bleaching deoxidizer, perfume and dye reducing agent, lignin removing agent for papermaking, etc.

●  Reductive bleaching agent has bleaching effect on food and has a strong inhibitory effect on oxidase in plant food. According to our country, it can be used for candied fruit, the maximum usage is 2.0g/kg; it can also be used for glucose, liquid glucose, table sugar, rock sugar, caramel, candy, bamboo shoots, mushrooms and canned mushrooms, grapes, blackcurrant concentrated juice, the maximum usage is 0.60g /kg. Residues of bamboo shoots, mushrooms and canned mushrooms, preserves, grapes and blackcurrant juice concentrate (calculated as SO2)≤0.05g/kg; potato starch residues≤0.03g/kg; residues of biscuits, sugar, vermicelli and other varieties The amount is less than 0.1g/kg; the residual amount of liquid glucose shall not exceed 0.2g/kg.

●  Used as common analytical reagents and photoresistor materials

●  For microanalytical determination of tellurium and niobium and formulation of developing solutions, also used as reducing agent

●  As a deoxidizer and bleaching agent in the printing and dyeing industry, it is used in the scouring of various cotton fabrics, which can prevent the local oxidation of cotton fibers and affect the fiber strength, and improve the whiteness of the scouring products. The photosensitive industry is used as a developer. It is used in the organic industry as a reducing agent for the production of m-phenylenediamine, 2,5-dichloropyrazolone, anthraquinone-1-sulfonic acid, 1-aminoanthraquinone, sodium aminosalicylate, etc., which can prevent semi-finished products during the reaction process. Oxidation. The paper industry is used as a lignin remover. The textile industry is used as a stabilizer for man-made fibers. The electronics industry is used to make photoresistors. The water treatment industry is used for the treatment of electroplating wastewater and drinking water.

●  Food industry is used as bleaching agent, preservative, bulking agent, antioxidant. Also used in pharmaceutical synthesis. Used as a reducing agent in the production of dehydrated vegetables.

●  It is used to make cellulose sulfite, sodium thiosulfate, organic chemicals, bleached fabrics, etc. It is also used as reducing agent, preservative, dechlorination agent, etc.

Production method

●  The absorption method absorbs sulfur dioxide with food-grade soda ash solution, makes it saturated, then adds refined sodium hydroxide solution, obtains crystalline sodium sulfite through crystallization, and then dehydrates by heating to obtain edible anhydrous sodium sulfite.

●  In the soda ash absorption method, the sulfur dioxide-containing gas obtained by burning sulfur is introduced from the bottom of the absorption tower, and is absorbed in countercurrent with the soda ash solution to generate sodium bisulfite solution and send it to the neutralization tank, and slowly add the soda ash solution to neutralize the reaction to slightly acidic. Then add caustic soda solution to make the pH value of the solution reach 11-12. After decolorization, filtration, evaporative crystallization, centrifugal dehydration, and air drying at 250-300 ℃, the clarified liquid is dried to obtain the finished product of anhydrous sodium sulfite. That
S+O2→SO2;
Na2CO3+SO2→Na2SO3+C02↑
Na2SO3+SO2+H2O→2NaHSO3
NaHSO3+NaOH→Na2SP3+H2O

●  The gas containing SOz produced by the combustion of sulfur is passed into the absorption tower and absorbed by the soda ash solution with a relative density of 1.21 (25°Bè) in countercurrent flow, and the pH value of the generated sodium bisulfite solution reaches 5 to 6. The soda ash solution of 1.21 was neutralized to slightly acidic, and then heated to above 102 °C; then the caustic soda solution with a relative density of 1.19 was added to neutralize to a Ph value of 11 to 12, iron was removed, and a sodium sulfite solution was obtained at the same time; the neutralization solution was vacuumed (26. 7kPa) evaporation concentration, crystallization separation, 250 ~ 300 ℃ air drying to remove crystal water to obtain the product.
Na2CO3+SO2+H2O→NaHSO3[NaOH]→Na2CO3

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