Ammonium sulfite

Ammonium sulfite

Names
IUPAC name Ammonium sulfite
Other names Ammonium sulphite, Diammonium sulfite, Diammonium sulfonate, Sulfurous acid, Diammonium salt, Sulfurous acid, ammonium salt(1:2)
Identifiers
CAS Number	17026-44-7 Y
3D model (Jmol)	Interactive image Interactive image
ChemSpider	23404 Y
ECHA InfoCard	100.030.428
InChI InChI=1S/2H3N.H2O3S/c;;1-4(2)3/h2*1H3;(H2,1,2,3) Y Key: PQUCIEFHOVEZAU-UHFFFAOYSA-N Y
SMILES [H][N+]([H])([H])[H].[H][N+]([H])([H])[H].O=S([O-])[O-] [O-]S([O-])=O.[NH4+].[NH4+]
Properties
Chemical formula	(NH4)2SO3
Molar mass	116.14 g/mol
Appearance	colourless[1] hygroscopic Crystals[2]
Melting point	65 °C (149 °F; 338 K) decomposes[1]
Solubility in water	35 g/100 mL[1] 32.4g/100mL at 0 degrees Celsius[3] 60.4g/100mL at 100 degrees Celsius[3]
Solubility	Insoluble in acetone and alcohol[2]
Refractive index (nD)	1.515.[3]
Hazards
NFPA 704	0 2 0
Flash point	Not Flamable[2]
Related compounds
Other anions	Ammonium hydroxide Ammonium thiosulfate Ammonium sulfate Ammonium bisulfate Ammonium persulfate
Other cations	Sodium Sulfite Potassium Sulfite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Ammonium sulfite is the ammonium salt of sulfurous acid with the chemical formula (NH₄)₂SO₃.

Preparation

Ammonium sulfite can be prepared by the reaction of ammonia with sulfur dioxide in aqueous solution:

2NH₃ + SO₂ + H₂O → (NH₄)₂SO₃

Uses

For cosmetics, ammonium sulfite is used as a hair straightening agent and a hair waving agent.^[4] Ammonium based hair products have been made to replace sodium hydroxide based products due to the destructive nature of sodium hydroxide on hair.

The most common food product with ammonium sulfite is caramel coloring. According to the FDA, caramel coloring contains ammonium, potassium, or sodium sulfite.^[5]

Ammonium sulfite is used as a preservative for fixers in photography. When film photographs are being developed ammonium sulfite can be one of the reducing agents used to preserve the hypo (Sodium or Ammonium Thiosulfate). Examples are given in Modern Photographic Processing, Volume I by Doctor Grant M. Haist of Eastman Kodak.

Ammonium sulfite can also be used in the making of bricks. The bricks made using ammonium sulfite are mainly used for blast furnace linings.^[6]

Ammonium sulfite can be included in lubricants for cold metal working. The lubricants are intended to reduce friction to keep heat production down and keep impurities out of the metals.^[6]

Ammonium sulfite has been used in gas scrubbers.^[7] The ammonium sulfite reacts with acidic air samples as a reducing agent. The Air is reduced to a more neutral pH which makes it less harmful to the environment.^[8]

Chemical Properties

Ammonium sulfite is a reducing agent.^[9] It emits sulfur dioxide and oxides of nitrogen upon heating to decomposition.

The specific gravity of ammonium sulfite is 1.41.^[2] The refractive index of ammonium sulfite is 1.515.^[3]

Hazards

Ammonium sulfite can be dangerous to handle. Ammonium sulfite has a toxic effect on humans. It is very hazardous in case of ingestion, it has a sulfurous taste. Ammonium sulfite is also hazardous in case of skin contact and it will irritate any skin that comes into contact with. Inhalation is another route of entry for ammonium sulfite to enter in a dangerous manner. Ammonium suifite is also hazardous when it comes into contact with eyes. The LD₅₀ has not been determined.^[2]

References