Hydroxylammonium sulfate

Chembox new
ImageFile = Hydroxylammonium-sulfate-2D-A.pngImageFile1 = Hydroxylammonium-sulfate-unit-cell-3D-balls.png Name = Hydroxylammonium sulfate
OtherNames = Hydroxylamine sulfate
Section1 = Chembox Identifiers
CASNo = 10039-54-0
EINECS = 233-118-8
Section2 = Chembox Properties
Formula = H₈N₂O₆S
MolarMass = 164.14 g mol⁻¹
Appearance = white crystalline to fine product, slightly hygroscopic
Density = 1.10 g cm⁻³, solid [http://www.inorganics.basf.com/p02/CAPortal/en_GB/portal/Hydroxylamin_freie_Base/content/Produktgruppen/Hydroxylaminverbindungen/Hydroxylammoniumsulfat/Hydroxylammoniumsulfat BASF hydroxylammonium sulfate product page] ]
MeltingPt = around 170 °C (decomposes)
BoilingPt =
Solubility = 370 g l⁻¹
Section7 = Chembox Hazards
ExternalMSDS = [http://msds.chem.ox.ac.uk/HY/hydroxylamine_sulfate.html Oxford PTCL MSDS]
EUClass = Corrosive (C) Harmful (Xi) Explosive (E)
NFPA-H = 3
NFPA-F = 1
NFPA-R = 2

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.

ynthesis

Hydroxylammonium sulfate can be obtained by the acid-base reaction of hydroxylamine with sulfuric acid:

:2NH₂OH(aq) + H₂SO₄(aq) → (NH₃OH)₂SO₄(aq)

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.

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. Metals (especially copper, its alloys and its salts) catalyse the decomposition of hydroxylammonium sulfate.

References