Sodium nitrite is a chemical compound with the formula NaNO₂. It is a white or slightly yellowish crystalline powder. It is highly soluble in water and has a salty taste. Sodium nitrite is an important inorganic compound with moderate stability. It can be easily oxidized to sodium nitrate in the air. It is a strong oxidizing agent in acidic solutions and can also act as a reducing agent in some cases.

Uses

In the Food Industry

It is mainly used as a food preservative and color fixative. In the processing of cured meats such as ham and bacon, sodium nitrite can inhibit the growth of harmful bacteria, especially Clostridium botulinum, thus extending the shelf life of food. Meanwhile, it reacts with myoglobin in meat to form nitrosomyoglobin, which gives the meat a bright red color, improving its appearance and palatability.

In the Chemical Industry

It serves as an important raw material for the synthesis of various organic and inorganic compounds. For example, it is used in the production of dyes, pharmaceuticals, and pesticides. In the dye industry, it is used in the diazotization reaction, which is crucial for the synthesis of azo dyes.

In the Metalworking Industry

Sodium nitrite is widely used as a rust inhibitor. It can form a protective film on the surface of metal parts, preventing them from being corroded by air and water. It is often added to metalworking fluids, such as cutting fluids and quenching fluids, to protect metal tools and workpieces during processing.

In the Pharmaceutical Industry

It has some applications in medicine. For example, it can be used in the treatment of cyanide poisoning. Sodium nitrite can react with hemoglobin in the blood to form methemoglobin, which can combine with cyanide ions to form relatively stable cyano-methemoglobin, thereby alleviating the toxicity of cyanide.

In the Rubber Industry

It is used in the rubber vulcanization process as an accelerator activator. It can improve the efficiency of the vulcanization reaction, shorten the vulcanization time, and improve the physical and mechanical properties of the rubber products.