Amidopermonosulphuric Acid, NH₂.O.SO₂.OH

When hydroxylamine is made to react with chlorosulphonic acid at the ordinary temperature, the hydroxyl group of the former undergoes sulphonation,3 as represented in the equation:

NH₂.OH + Cl.SO₂.OH = NH₂.O.SO₂.OH + HCl.

The same substance can also be obtained from hydroxylamine sulphate and fuming sulphuric acid, and by the hydrolysis of hydroxylamineisodisulphonic acid with hydrochloric acid.

The product is a microcrystalline powder which can be hydrolysed to hydroxylamine by heating in acid solution.

As will be seen by comparing the formulae of sulphuric acid, SO₂(OH)₂, and sulphamide, SO₂(NH₂)₂, hydroxylamineisosulphonic acid is the amide corresponding with permonosulphuric acid, although it has not been directly prepared from this acid. In agreement with this relationship, however, hydroxylamineisosulphonic acid or amidopermonosulphuric acid possesses marked oxidising properties, readily liberating iodine from potassium iodide.