Understanding Sodium Nitrite, its Uses and Associated Hazards

Have you ever been to a meat shop, if you did, you must have seen meat laced with white colour stuff looks like crushed ice that is called Sodium Nitrite? The chemical formula of this fixative and preservative is NaNO2 and is a yellowish colour crystalline power, soluble in water.


Definition of the sodium nitrite-

“Sodium nitrite is the inorganic compound with the chemical formula NaNO2. It is a white to slight yellowish crystalline powder that is very soluble in water and is hygroscopic. It is a useful precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive to prevent botulism.” (Source: wikipedia.org)


Here, most of the people also confuse sodium with salt, but in real, they are different. To be clearer, when we talk about salt, it is actually sodium, but on other side, sodium is not a salt.


Any Difference between sodium nitrate and sodium nitrite -

Both the chemicals share the inheritance as they both comes from the same family. The humankind is using these chemicals from ages but nitrites are excessively easier to work with as compared to nitrates. The other difference between these two chemicals is their uses that are discussed below.


What are the uses of Sodium Nitrite?

Unlikely, sodium nitrate, which is used to make explosives, glass and fertilizers, sodium nitrite is used for meat preservation. If you ever tried Ham, you must have seen the pink coloration and sometime distinctive taste, this is what caused by this particular chemical. Besides meat preservation, this chemical is also used in followings:-

• dyes manufacturing
• paint pigments
• dye and printing inks
• photography
• corrosion inhibitor
• laboratory reagent
• metal coating
• rubber manufacturing chemicals

Hazards involved in its uses are -

In United States of America, this particular chemical is produced within prescribed limits, which are as low as they can be. The medical researches done for this particular topic have evidences that imbalance intake of sodium nitrite can adversely affect the haemoglobin by reducing blood ability to carry oxygen. There are evidences that excessive use of this chemical can even lead to cancer as well.

Learning About The Basic Properties Of Sodium Nitrite

Sodium nitrite is a stable, odorless compound having a molecular weight of 69.00. This sodium salt of nitrous acid is pale yellow or straw colored and is available in either the form of dry granules, flakes and even water solutions. The compound needs to be handled carefully while using, storing or even shipping it from one destination to another mainly because it is an oxidizer and toxic in nature.


Sodium Nitrite is generally produced for industrial use by making the oxides of nitrogen to get absorbed into sodium carbonate or sodium hydroxide solutions. The sodium nitrite solution produced by this method is then concentrated to produce slurry of crystals acquired by using the conventional evaporation and crystallization equipments. To separate the crystals form the original liquid, the centrifugation technique is generally used. Once the crystals have been separated, they are dries and treated with an anti-caking agent to ensure that they remain in the free-flowing form. The other methods of producing the compound involve various chemical reactions carried out with the aim of reducing sodium nitrate to yield sodium nitrite.


In its pure form, anhydrous Sodium nitrite has a specific gravity of 2.168 at 0ºC/0°C. The melting point of the compound is 284°C while it starts to decompose when the temperature goes beyond 320°C, to release N2O2, NO, and Na2O. Within the temperature range of 158–165°C, the physical properties of sodium nitrite undergo a significant change. The compound, in addition to being water soluble, also possesses hygroscopic properties. Sodium nitrite displays a stable nature in alkaline solutions but when exposed to acidic solutions, the compound releases unstable nitrous acid. The compound serves as a primary source of nitrous acid, used for organic synthesis.


When exposed to atmospheric oxygen, sodium nitrite oxidizes spontaneously to form the brown-colored compound named nitrogen-dioxide. The compound can convert ammonium ion to nitrogen, urea to carbon dioxide and nitrogen, and sulfamate to sulfate and nitrogen which makes it a good oxidizing agent. This makes it perfect for use in various industries including manufacturing of dye, rubber chemicals and pharmaceuticals, as a corrosion inhibitor, in heat treating and heat-transfer salts, in meat curing, and several other applications.


Royce is a fully diversified international company which was founded in 1929 to manufacture chemicals for textile industry. Today more than 80 years later, they have a resounding presence across the world and offer solution to diverse needs of chemicals to their customers which also include sodium nitrite.

Learning About The Various Uses of Sodium Nitrite

For decades sodium nitrite has been put to use in various industries such as food processing and textile, glass and even pharmaceutical. This chemical, which is white or slightly yellowish crystalline powder in its pure form, is water soluble and gets oxidized into sodium nitrate with the help of atmospheric oxygen. The immense popularity of sodium nitrite as an industrial compound is mainly due to its great oxidizing properties as well as its ability to release nitrous acid in acidic solutions. Given below are some of the common industrial uses of this compound.


As a Food Additive
Over the years, sodium Nitrite has been invariably used by the processed food industry for preserving a variety of foods, especially fish and meat. The chemical not only helps in changing the color of the preserved fish and meat but also prevents the growth of many harmful bacteria. However, in the recent years, questions have been raised about the safety of this chemical as a food additive, mainly because of the toxic nature of the compound and if consumed in large amounts, it can prove fatal not only for animals, but humans as well.


In The Manufacture Of Dyes and Rubber Chemicals
Sodium nitrite is one of the most vital ingredients used for manufacturing rubber processing chemicals such as accelerators, retarders, anti-oxidants, and anti-ozonants. The chemical is also an integral part of the manufacturing process of azo dyes, mainly due to the fact that it is a convenient source of nitrous acid. Nitrous acid plays an important role in the nitrosation and diatozation of aromatic amines, which results in the production of the intermediate diamine salts. These salts then combine with amines, phenols, naphthols, and other compounds to form the azo dyes.


As A Corrosion Inhibitor
Sodium nitrite helps in preventing the corrosion of ferrous metals as it forms a firmly held layer of oxide over these metals. This prevents the dissolution of metal at the anodic areas. While it can prevent the corrosion of steel on its own, the compound may be used in combination with some other synergistic additives to ensure total protection against corrosion in case of mixed metal systems containing some percentage of various metals such as copper, brass, or aluminum. In the recent years the reduction in the use of carcinogenic hexavalent chromium-based corrosion inhibitors has also lead to an increased interest in the use of sodium nitrite as a corrosion inhibitor.