Production and uses of nitrogen

Campbell, Energy and the Atmosphere, 2nd edn. Wiley, London, 1986, Nitrogen cycles, pp 169-81. 

Laboratory routes to highly purified N2 are seldom required. Thermal decomposition of sodium azide at 300° C under carefully controlled conditions is one possibility  

Hot aqueous solutions of ammonium nitrite also decompose to give nitrogen though small amounts of NO and HNO3 are also formed (p. 434) and must be removed by suitable absorbents such as dichromate in aqueous sulfuric acid  

Other routes are the thermal decomposition of (NH4)2Cr207, the reaction of NH3 with bromine water, or the high-temperature reaction of NH3 

Grant and S. L. Redfearn, Industrial gases, in R. Thompson (ed.), The Modem Inorganic Chemicals Industry, Chem. Soc. Special Publ. 31, 273-301 (1977). 

Elemental nitrogen is obtained in commercial quantities by fractional distillation of liquid air. About 4 X kg (40 million tons) of N2 is produced annually in the United States. 

Because of its low reactivity, large quantities of N2 are used as an inert gaseous blanket to exclude O2 in food processing, manufacture of chemicals, metal fabrication, and production of electronic devices. Liquid N2 is employed as a coolant to freeze foods rapidly. 

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Research work on the production and use of coated urea for controlled release of nitrogen is being continued. TVA hopes to reduce the ratio of nozzles to production rate and further decrease the size of the sulfur-coating equipment. A thorough agronomic evaluation of the material coated only with sulfur is being conducted which will fully indicate its potentials as a slow-release fertilizer. TVA plans to initiate demonstration-scale production of sulfur-coated urea in about 1975-76. Production rate for this unit will be about 10 tons/hr. 

Positioning a carbonyl substituent on the nitrogen results in a change of selectivity in favor of o-metallation [49,77]. With a Boc substituent (in 32), orthosubstitution is the sole product and use of a chiral amine allows modest chiral induction as shown in [77]. 

These reactions go substantially to completion in most granulation processes, in nitrophosphate processes, and in liquid compound fertilizer processes. Ando et al. found that ammonium chloride was one of the most common forms of nitrogen in representative grades of NPK granular fertilizers in the United States 165], Thus, the production and use of compound fertilizers containing ammonium chloride is well established on a worldwide basis even though some people in the industry are not aware of it. 

Based on this process, the Gutehoffnungshutte Company built the first industrial-scale plant for production of formaldehyde by direct oxidation of natural gas in Romania (Copsa Mica) in 1942 (Fig. 11.6). The process was conducted at 400—600 °C with a 10-fold gas circulation and use of nitrogen oxides as a homogeneous catalyst. The optimum concentration of nitrogen oxides was 0.08%. Its further increase caused a decrease in the selectivity to formaldehyde because of the formation of carbon oxides. The efficiency of methane use (in terms of fresh gas) was 8%. About 30% of the methane was oxidized to CO, CO2, and H2O, with the rest being the unconverted methane. As a result, the formation of one formaldehyde molecule is accompanied by the formation of no less than 7—8 water molecules. The concentration of formaldehyde in the reaction gas was 0.16—24%. The reaction gases, cooled to... 

Markets. Industrial use of ammonia varies according to region. Eor example, industrial usage represents 20% of the ammonia production in the United States and Western Europe, 10% in the USSR, 1—10% in Asia, and 5% in Latin America and North Africa (79). Fertiliser ammonia consumed domestically in most countries is converted to straight or compound fertilisers such as urea, ammonium nitrate, diammonium phosphate, and various grades of mixed fertilisers. However, almost 29% of ammonia nitrogen in the United States is consumed as direct appHcation material. The use of nitrogen solution such as urea and ammonium nitrate (UAN) has also become popular in the United States and the USSR. 

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