Hydroxylammonium sulfate, (NH3OH)2SO4, is the sulfuric acid salt of hydroxylamine. It is primarily used as an easily-handled form of hydroxylamine, which is explosive when pure.
Hydroxylammonium sulfate can be obtained by the acid-base reaction
of hydroxylamine with sulfuric acid:
- 2NH2OH(aq) + H2SO4(aq) → (NH3OH)2SO4(aq)
Hydroxylammonium sulfate is used in organic synthesis
to convert aldehydes
, carboxylic acids
and their derivatives (e.g. esters
) to hydroxamic acids
to N-hydroxyureas and nitriles
. Hydroxylammonium sulfate is also used to generate hydroxylamine-O-sulfonic acid
or chlorosulfuric acid
Hydroxylammonium sulfate is used in the production of anti-skinning agents, pharmaceuticals, rubber, textiles, plastics and detergents. It is a radical scavenger that terminates radical polymerization reactions and serves as an antioxidant in natural rubber. (NH3OH)2SO4 is a starting material for some insecticides, herbicides and growth regulators. It is used in photography as a stabiliser for colour developers and as an additive in photographic emulsions in colour film.
At 120 °C, hydroxylammonium sulfate begins to decompose to sulfur trioxide
, nitrous oxide
, and ammonia
- 2(NH3OH)2SO4 → 2SO3 + N2O + 2NH3 + 5H2O
The reaction is exothermic above 138 °C, and is most exothermic at 177 °C. Metals (especially copper, its alloys and its salts) catalyse the decomposition of hydroxylammonium sulfate.