Hydroxylamine

hydroxylamine [‚hī‚dräk′sil·ə‚mēn]

(inorganic chemistry)

NH₂OH A colorless, crystalline compound produced commercially by acid hydrolysis of nitroparaffins, decomposes on heating, melts at 33°C; used in organic synthesis and as a reducing agent.

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Hydroxylamine 

H₂NOH, is the product of the replacement of one hydrogen atom in the ammonia molecule (NH₃) by an OH group. It forms colorless acicular crystals. Density, 1,204.4 kg/m³ (at 23.5° C); melting point, 33°-34° C; boiling point, 58° C at 2.933 kilonewtons per sq m (22 mm Hg). Hydroxylamine is stable at 0° C; at 20° C it decomposes slowly. An increase in temperature accelerates the decomposition, and at 130° C it explodes.

Hydroxylamine is hygroscopic. It dissolves readily in water to form hydroxylamine hydrate, which is a weak base: NH₂OH·H₂O ⇆ NH₃OH⁺ + OH⁻. Upon reaction with acids, hydroxylamine hydrate gives hydroxyammonium salts—for example, NH₃OHCl and (NH₃OH)₂SO₄—which have strong reducing properties. Hydroxylamine dissolves readily in methyl and ethyl alcohols but is insoluble in acetone, benzene, and petroleum ether. It is oxidized by atmospheric oxygen to HNO₂. Hydroxylamine sulfate is produced industrially by reducing sodium nitrite with sulfur dioxide in the presence of sodium carbonate. Free hydroxylamine is produced by distilling alkaline solutions of the salts. Hydroxylamine and its derivatives are poisonous. Salts of hydroxylamine are extensively used in the pharmaceutical industry, in making kapron, and in analytical chemistry.

REFERENCE

Brikum, I. K., M. T. Kozlovskii, and L. V. Nikitina. Gidrazin igidroksilamin i ikh primenenie v analiticheskoi khimii. Alma-Ata, 1967.

V. S. LAPIK