The use of nitrogen How to prepare nitrogen

What are the uses of nitrogen? Nitrogen is often referred to as an inert gas. It is used in certain inert atmospheres for metal treatment and in bulbs to prevent arcing, but it is not chemically inert. It is an essential element in the life of plants and animals, and is a component of many useful compounds. Nitrogen combines with many metals to form hard nitrides, which can be used as wear-resistant metals. A small amount of nitrogen in steel will inhibit grain growth at high temperatures and will also increase the strength of certain steels. It can also be used to produce hard surfaces on steel. Nitrogen can be used to make ammonia, nitric acid, nitrate, cyanide, etc.; in the manufacture of explosives; filling high-temperature thermometers, incandescent bulbs; forming inert materials to preserve materials, used in drying boxes or glove bags. Liquid nitrogen during food freezing; used as a coolant in the laboratory.

Nitrogen, whose chemical formula is N?, is a colorless and odorless gas. Nitrogen is chemically inactive. It can react with hydrogen to form ammonia under high temperature, high pressure and catalyst conditions; it can combine with oxygen to form nitric oxide under discharge; even active metals such as Ca, Mg, Sr and Ba can only be It can only react with it when heated. This high degree of chemical stability of nitrogen is related to its molecular structure. Two N atoms are combined with a triple bond to form a nitrogen molecule, including one σ bond and two π bonds, because the first to be attacked in a chemical reaction is the π bond, and the energy level of the π bond in the N? molecule is lower than that of the σ bond. , It is difficult to open the π bond, which makes it difficult for N? to participate in the chemical reaction.

There are about 4,000 trillion tons of gas in the atmosphere, of which nitrogen accounts for 78%. Nitrogen is slightly soluble in water and alcohol. It is non-flammable and is considered a suffocating gas (that is, breathing pure nitrogen will deprive the human body of oxygen). Although nitrogen is considered an inert element, it forms some very active compounds. It can be used as a diluent and control the natural burning and breathing rate, which will be faster at higher oxygen concentrations.

Nitrogen is soluble in water and alcohol, but basically insoluble in most other liquids. It is essential in life, and its compounds can be used as food or fertilizer. Nitrogen is used to make ammonia and nitric acid. Nitrogen is basically an inert gas at ambient temperature and moderate temperature. Therefore, most metals are easy to handle. At elevated temperatures, nitrogen can be aggressive to metals and alloys.

Nitrogen preparation method

Cryogenic separation method: Cryogenic separation method, also known as cryogenic rectification method, uses the inconsistent boiling point of nitrogen and oxygen in the air to separate oxygen and nitrogen. Since the boiling point of nitrogen (-196°C) is lower than that of oxygen (-183°C), during the evaporation of liquid air, liquid nitrogen is more likely to become gaseous than liquid oxygen, and during air liquefaction, oxygen is easier to change than nitrogen. Into a liquid state. Since the boiling points of nitrogen and oxygen are not much different, liquid air and gaseous air need to undergo repeated evaporation, condensation, and reevaporation processes (this process is called cryogenic rectification process), and finally it can be in the gas phase fraction at the top of the rectifying tower. High-purity nitrogen is passed. The purity of nitrogen depends on the number of stages of the rectification tower and the rectification efficiency.