Production
Industrial production of sodium nitrite follows one of two processes, the reduction of nitrate salts, or the oxidation of lower nitrogen oxides. One method uses molten sodium nitrate as the salt, and lead which is oxidized, while a more modern method uses scrap iron filings to reduce the nitrate.A more commonly used method involves the general reaction of nitrogen oxides in alkaline aqueous solution, with the addition of a catalyst. The exact conditions depend on which nitrogen oxides are used, and what the oxidant is, as the conditions need to be carefully controlled to avoid over oxidation of the nitrogen atom.Sodium nitrite has also been produced by reduction of nitrate salts by exposure to heat, light, ionizing radiation, metals, hydrogen, and electrolytic reduction. Chemical reactions
In the laboratory, sodium nitrite can be used to destroy excess sodium azide.
Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite salt. It is a precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products. Uses
Industrial chemistry
The main use of sodium nitrite is for the industrial production of organonitrogen compounds. It is a reagent for conversion of amines into diazo compounds, which are key precursors to many dyes, such as diazo dyes. Nitroso compounds are produced from nitrites. These are used in the rubber industry.It is used in a variety of metallurgical applications, for phosphatizing and detinning.Sodium nitrite is an effective corrosion inhibitor and is used as an additive in industrial greases, as an aqueous solution in closed loop cooling systems, and in a molten state as a heat transfer medium. Food additive and preservative
Sodium nitrite is used to speed up the curing of meat and also impart an attractive pink color. Nitrite reacts with the meat myoglobin to cause color changes, first converting to nitrosomyoglobin (bright red), then, on heating, to nitrosohemochrome (a pink pigment).Historically, salt has been used for the preservation of meat. The salt-preserved meatproduct was usually brownish-gray in color.