Nitrogen

Applications

Nitrogen Compounds

Molecular nitrogen in the atmosphere is relatively non-reactive, but in nature it is slowly converted into biologically (and industrially) useful compounds by some living organisms, notably certain bacteria (see Biological role below). The ability to combine or fix nitrogen is a key feature of modern industrial chemisty, where nitrogen (along with natural gas) is converted into ammonia (via the Haber process). Ammonia, in turn, can be used directly (primarily as a fertilizer), or as a precursor of many other important materials including explosives, largely via the production of nitric acid by the Ostwald process.

Related Topics:
Bacteria - Natural gas - Ammonia - Haber process - Fertilizer - Explosives - Nitric acid - Ostwald process

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The salts of nitric acid include important compounds like potassium nitrate (or saltpeter, important historically for its use in gunpowder) and ammonium nitrate, an important fertilizer. Various other nitrated organic compounds, such as nitroglycerin and trinitrotoluene, are used as explosives. Nitric acid is used as an oxidizer in liquid fueled rockets. Hydrazine and hydrazine derivatives find use as rocket fuels.

Related Topics:
Potassium nitrate - Gunpowder - Ammonium nitrate - Nitroglycerin - Trinitrotoluene - Rocket - Hydrazine - Fuel

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Molecular nitrogen (gas and liquid)

Nitrogen gas is readily produced by allowing liquid nitrogen (see below) to warm up and evaporate. It has a wide variety of applications, including serving as a more inert replacement for air where oxidation is undesireable;

Related Topics:
Evaporate - Oxidation

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• to preserve the freshness of packaged or bulk foods (by delaying rancidity and other forms of oxidative damage)
• on top of liquid explosives for safety

It is also used in:

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• the production of electronic parts such as transistors, diodes, and integrated circuits
• the manufacture of stainless steel
• filling automotive tires due to its relatively flat line of thermal expansion.

A futher example of its versitility is its use (as a preferred alternative to carbon dioxide) to pressurize kegs of some beers, particularly thicker stouts and Scottish and English ales, due to the smaller bubbles it produces, which make the dispensed beer smoother and headier. A modern application of a pressure sensitive nitrogen capsule known commonly as a "widget" now allows nitrogen charged beers to be packaged in cans and bottles. A very popular example of this is Guinness Draught.

Related Topics:
Carbon dioxide - Beer - Stouts - Guinness Draught

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Liquid nitrogen is produced industrially in large quantities by distillation from liquid air and is often referred to by the quasi-formula LN2. It is a cryogenic (extremely cold) fluid which can cause instant frostbite on direct contact with living tissue (skin). When appropriately insulated from ambient heat it serves as a compact and readily transported source of nitrogen gas without pressurization. Further, its ability to maintain an unearthly temperature as it evaporates (77 K, minus 196 deg.C or minus 320 deg.F!) makes it extremely useful in a wide range of applications as an open-cycle refrigerant, including;

Related Topics:
Distillation - Liquid air - Cryogenic - Insulated - Heat - Refrigerant

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• the immersion freezing and transportation of food products
• the preservation of bodies, reproductive cells (sperm and egg), and biological samples and materials
• in the study of cryogenics
• for demonstrations in science education
• in dermatology for removing unsightly or potentially malignant skin lesions,e.g., warts, actinic keratosis, etc.