hydrazine [key], chemical compound, formula NH2NH2, m.p. 1.4℃, b.p. 113.5℃, specific gravity 1.011 at 15℃. It is very soluble in water and soluble in alcohol. At ordinary temperatures it is a colorless, fuming liquid that has an ammonialike odor, but when frozen it forms white crystals. Hydrazine is corrosive and a strong reducing agent, but it is a weaker base than ammonia. It reacts with water to form hydrazine hydrate, N2H4·H2O, a colorless liquid that boils at 120℃. Hydrazine can be prepared (usually as the hydrate) by reacting ammonia with chloramine, NH2Cl, in the presence of glue or gelatin. The glue or gelatin inhibits decomposition of the hydrazine. Ammonium chloride is a byproduct. The chloramine may be prepared by reacting ammonia with a hypochlorite or chlorine gas. Hydrazine is also prepared by reaction of sodium hypochlorite with urea in the presence of glue or gelatin. Hydrazine is dibasic and forms many salts, e.g., mono- and di-hydrochlorides, mono- and di-nitrates, and two sulfates. The major use of hydrazine is as a rocket fuel because it burns rapidly, producing a large amount of heat. Hydrazine and its derivatives are also used in the manufacture of algicides, fungicides, insecticides, and agricultural chemicals; in rubber curing and the manufacture of foam rubber and plastics; in soldering fluxes; and as a corrosion inhibitor in boiler feedwater. Isoniazid, a drug used in treatment of tuberculosis, is isonicotinic hydrazide.
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