Hydrazine (redirected from Hydrazines)

hydrazine (hī`drəzēn'), chemical compound, formula NH₂NH₂, m.p. 1.4°C;, b.p. 113.5°C;, specific gravity 1.011 at 15°C;. 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°C;. 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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hydrazine [′hī·drə‚zēn]

(inorganic chemistry)

H₂NNH₂A colorless, hygroscopic liquid, boiling point 114°C, with an ammonialike odor; it is reducing, decomposable, basic, and bifunctional; used as a rocket fuel, in corrosion inhibition in boilers, and in the synthesis of biologically active materials, explosives, antioxidants, and photographic chemicals.

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Hydrazine 

(also called diamide), H₂N—NH₂, a colorless, hygroscopic liquid that fumes in air. Boiling point, 113.5° C; melting point, 2° C; density, 1,008 g/cm³ (at 20° C). Hydrazine is absolutely soluble in water and low alcohols. It is insoluble in hydrocarbons and other organic solvents. Aqueous solutions of hydrazine are basic (K = 8.5 x 10⁻⁷). With acids it forms salts of hydrazone, such as N₂H₅C1 and N₂H₆C1₂. Hydrazine is characterized by a high dielectric constant (52.9 at 20° C) and is able to dissolve many inorganic salts.

Hydrazine is an endothermal compound; heat of formation ΔH (1) = 50.24 kilojoules per mole (12.05 kilocalories per mole). Upon heating to 200°-300° C, hydrazine decomposes to N₂ and NH₃. In the presence of Fe₂0₃, it ignites at room temperature. A mixture of hydrazine vapor with air at a content of 4.67 percent or more by volume forms an explosive mixture. Liquid hydrazine is not sensitive to impact, friction, or detonation. It is toxic; the maximum permissible concentration in air is 0.0001 mg/l. Hydrazine is produced by oxidation of NH₃ or urea by hypochloride. It is used in organic synthesis, as a component of liquid rocket fuels, and in the production of plastics, cured rubber, insecticides, and explosives.

REFERENCE

Audrieth, L., and B. Ogg. Khimiia gidrazina. Moscow, 1954. (Translated from English.)

V. S. LAPIK