Hydroxylammonium sulfate
From Wikipedia, the free encyclopedia
| Hydroxylammonium sulfate | |
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| Other names | Hydroxylamine sulfate |
| Identifiers | |
| CAS number | [10039-54-0] |
| EINECS number | |
| Properties | |
| Molecular formula | H8N2O6S |
| Molar mass | 164.14 g mol−1 |
| Appearance | white crystalline to fine product, slightly hygroscopic |
| Density | 1.10 g cm−3, solid[1] |
| Melting point |
around 170 °C (decomposes) |
| Solubility in water | 370 g l−1 |
| Hazards | |
| MSDS | Oxford PTCL MSDS |
| EU classification | Corrosive (C) Harmful (Xi) Explosive (E) |
| NFPA 704 |
 1
3
2
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| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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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.
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[edit] Synthesis
Hydroxylammonium sulfate can be obtained by the acid-base reaction of hydroxylamine with sulfuric acid:
- 2NH2OH(aq) + H2SO4(aq) → (NH3OH)2SO4(aq)
[edit] Applications
Hydroxylammonium sulfate is used in organic synthesis to convert aldehydes and ketones to oximes, carboxylic acids and their derivatives (e.g. esters) to hydroxamic acids, isocyanates to N-hydroxyureas and nitriles to amidoximes. Hydroxylammonium sulfate is also used to generate hydroxylamine-O-sulfonic acid from oleum 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.
[edit] Decomposition
At 120 °C, hydroxylammonium sulfate begins to decompose to sulfur trioxide, nitrous oxide, water, and ammonia:
- 2(NH3OH)2SO4 → 2SO3 + N2O + 2NH3 + 5H2O
The reaction is exothermic above 138 °C, and is most exothermic at 177 °C[1]. Metals (especially copper, its alloys and its salts) catalyse the decomposition of hydroxylammonium sulfate.
