Hydroxylammonium sulfate is the inorganic compound with the formula [NH3OH]2SO4. A colorless solid, it is the sulfate salt of hydroxylamine. It is primarily used as an easily handled form of hydroxylamine, which is a volatile liquid.[2]
Production
Hydroxylammonium sulfate is prepared industrially by protonation of hydroxylamine. The latter is produced by the hydrogenation of nitric oxide using a platinum catalyst:[2]
- 2 NO + 3 H2 + H2SO4 → [NH3OH]2[SO4]
Another route to NH2OH is the Raschig process: aqueous ammonium nitrite is reduced by HSO−3 and SO2 at 0 °C to yield a hydroxylamido-N,N-disulfonate anion::[3]
- [NH4]+[NO2]− + 2 SO2 + NH3 + H2O → [NH4]2[HON(SO3)2]
This ammonium hydroxylamine disulfonate anion is then hydrolyzed to give hydroxylammonium sulfate:
- [NH4]2[HON(SO3)2] + 2 H2O → [HONH3]2SO4
Applications
Almost all hydroxylamine and its salts are used to make precursors to nylons via cyclohexanone oxime.[2] Many aldehydes and ketones undergo the same conversion to oximes. carboxylic acids and their derivatives (e.g. esters) convert to hydroxamic acids. Isocyanates to N-hydroxyureas. Nitriles react to give amidoximes. Hydroxylammonium sulfate is also used to generate hydroxylamine-O-sulfonic acid from oleum or from 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.
Structure
Hydroxylammonium sulfate exists as tetrahedral NH3OH+ cations and sulfate anions.
Safety
Hydroxylamine, which occurs widely in nature, has low toxicity. The compound is stable below 120 °C.[2]
References
- ^ Mirceva, A.; Golic, L. (15 May 1995). "Hydroxylammonium Sulfate". Acta Crystallographica Section C Crystal Structure Communications. 51 (5): 798–800. Bibcode:1995AcCrC..51..798M. doi:10.1107/S0108270194013351.
- ^ a b c d Ritz, Josef; Fuchs, Hugo; Perryman, Howard G. (2000). "Hydroxylamine". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_527. ISBN 3527306730.
- ^ Oblath, S. B.; Markowitz, S. S.; Novakov, T.; Chang, S. G. (December 1982). "Kinetics of the initial reaction of nitrite ion in bisulfite solutions" (PDF). The Journal of Physical Chemistry. 86 (25): 4853–4857. doi:10.1021/j100222a005.