Sodium Nitrite CAS 7632-00-0

Nitrite is part of the average person’s daily diet and is found in many vegetables. In 34 kinds of vegetables, including different kinds of cabbage, lettuce, spinach, coriander, and radish, the nitrite content was usually between 1.1 and 57 mg/kg. The process of cooking vegetables may cause the loss of nitrate, nitrous acid The loss of salt is not significant. Raw meat contains 0.4–0.5 mg/kg nitrite and 4–7 mg/kg nitrate, while cured meat contains 10–30 mg/kg nitrate.

The metabolite of nitrite in animal tissues is usually nitric oxide, an important neurotransmitter. Nitric oxide can be initially produced from arginine by nitric oxide synthase or from nitrate and nitrite absorbed by digestion. Early research on the negative effects of nitrite on the human body led people to recognize the important role of nitric oxide in human metabolism and to know that the human body itself produces nitric oxide endogenously.

As a food additive, sodium nitrite can not only dye and preserve fish and meat food, the principle is: nitrite decomposes under acidic conditions to produce nitroso (NO), which will quickly interact with myoglobin. The reaction produces stable, bright, bright red nitrosomyoglobin. Keeps meat products a consistent bright red color. Therefore, it is especially suitable for luncheon meat, ham sausages, etc., while canned braised meat, canned stewed pork, stewed elbows and other meat products use natural color, and generally do not add sodium nitrite as a color-preserving agent. The international food additive code (INS number) of sodium nitrite is 250, so some food labels indicate the use of No. 250 additive, which is the taboo name of sodium nitrite.

Sodium nitrite can also inhibit the growth of botulinum bacteria. The latter can produce botulinum toxin, which can cause food poisoning. Under the EU standard, sodium nitrite can only be mixed with edible salt in a content not higher than 0.6%, and its E code is E250. The standard for potassium nitrite is similar.

This compound can inhibit bacterial growth, and correspondingly, at relatively high levels, it is also significantly toxic to animals, including humans. The median lethal dose of sodium nitrite for rats is 180 mg/kg, and the lowest known lethal dose for humans is 71 mg/kg, which means that a person weighing 65 kg may be killed by a minimum of 4.615 g of this substance. To avoid accidental ingestion, sodium chloride mixed with sodium nitrite (used for non-dietary purposes) is often dyed a light red.

Recent studies have found that sodium nitrite has significant effects on dilating blood vessels and improving blood circulation, including application prospects for sickle cell disease, cyanide poisoning, myocardial infarction, cerebral aneurysm, and pulmonary hypertension, some of which are currently Can cause infant death. Intravenous sodium nitrite is now used in first aid for cyanide poisoning. (see cyanide #detoxification)

Sodium nitrite is used for the conversion of amines to diazonium compounds, and the N2 group has good leaving properties, and such reactions are used to replace amino groups in production applications.

In the laboratory, sodium nitrite is also used to treat excess sodium azide.

When sodium nitrite is heated to a higher temperature (above 330 °C), it can decompose to produce sodium oxide, reddish-brown nitrogen dioxide and nitric oxide.

Sodium oxide can absorb carbon dioxide to produce sodium carbonate, which may have prevented the crew of the first submarine from suffocating at high concentrations of carbon dioxide.