Hydroxylamine

Hydroxylamine (also known as Hydroxyammonia) is an inorganic compound with the formula . The material is a white crystalline, hygroscopic compound. Hydroxylamine is almost always provided and used as an aqueous solution. It is consumed almost exclusively to produce Nylon-6. The oxidation of to hydroxylamine is a step in biological nitrification. Hydroxylamine was first prepared as hydroxylammonium chloride in 1865 by the German chemist Wilhelm Clemens Lossen (1838-1906); he reacted tin and hydrochloric acid in the presence of ethyl nitrate. It was first prepared in pure form in 1891 by the Dutch chemist Lobry de Bruyn and by the French chemist Léon Maurice Crismer (1858-1944). The coordination complex , known as Crismer's salt, releases hydroxylamine upon heating. Hydroxylamine or its salts can be produced via several routes but only two are commercially viable. It is also produced naturally as discussed in a section on biochemistry. is mainly produced as its hydrogen sulfate by the hydrogenation of nitric oxide over platinum catalysts in the presence of sulfuric acid. Another route to is the Raschig process: aqueous ammonium nitrite is reduced by and at 0 °C to yield a hydroxylamido-N,N-disulfonate anion: This anion is then hydrolyzed to give hydroxylammonium sulfate : Solid can be collected by treatment with liquid ammonia. Ammonium sulfate, , a side-product insoluble in liquid ammonia, is removed by filtration; the liquid ammonia is evaporated to give the desired product. The net reaction is: Hydroxylammonium salts can then be converted to hydroxylamine by neutralization: Julius Tafel discovered that hydroxylamine hydrochloride or sulfate salts can be produced by electrolytic reduction of nitric acid with HCl or respectively: Hydroxylamine can also be produced by the reduction of nitrous acid or potassium nitrite with bisulfite: (100 °C, 1 h) Hydroxylamine reacts with electrophiles, such as alkylating agents, which can attach to either the oxygen or the nitrogen atoms: The reaction of with an aldehyde or ketone produces an oxime.