Ammonium acetate

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Ammonium acetate
Identifiers
CAS number631-61-8 YesY
PubChem517165
ChemSpider11925 YesY
UNIIRRE756S6Q2 YesY
ChEBICHEBI:62947 N
RTECS numberAF3675000
Jmol-3D imagesImage 1
Properties
Molecular formulaNH4C2H3O2, C2H7NO2
Molar mass77.0825 g/mol
Appearancewhite solid crystals
deliquescent
Density1.073 g/cm3[1]
Melting point114 °C; 237 °F; 387 K
Boiling pointdecomposes
Solubility in water148 g/100 ml (4 °C)
Solubility in methanol7.89 g/100 mL (15 °C)
Structure
Crystal structureorthorhombic
Hazards
MSDSJT Baker
GHS pictogramsGHS-pictogram-exclam.svg[2]
GHS hazard statementsH315, H319, H335[2]
GHS precautionary statementsP261, P305+351+338[2]
NFPA 704
NFPA 704.svg
1
2
1
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
 
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Ammonium acetate
Identifiers
CAS number631-61-8 YesY
PubChem517165
ChemSpider11925 YesY
UNIIRRE756S6Q2 YesY
ChEBICHEBI:62947 N
RTECS numberAF3675000
Jmol-3D imagesImage 1
Properties
Molecular formulaNH4C2H3O2, C2H7NO2
Molar mass77.0825 g/mol
Appearancewhite solid crystals
deliquescent
Density1.073 g/cm3[1]
Melting point114 °C; 237 °F; 387 K
Boiling pointdecomposes
Solubility in water148 g/100 ml (4 °C)
Solubility in methanol7.89 g/100 mL (15 °C)
Structure
Crystal structureorthorhombic
Hazards
MSDSJT Baker
GHS pictogramsGHS-pictogram-exclam.svg[2]
GHS hazard statementsH315, H319, H335[2]
GHS precautionary statementsP261, P305+351+338[2]
NFPA 704
NFPA 704.svg
1
2
1
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Ammonium acetate is a chemical compound with the formula NH4C2H3O2 (or C2H4O2.NH3 or C2H7NO2). It is a white solid and can be derived from the reaction of ammonia and acetic acid. It is available commercially and, depending on grade, can be rather inexpensive.

Uses and distinctive properties[edit]

Ammonium acetate

As the salt of a weak acid and a weak base, ammonium acetate has a number of distinctive properties.

Ammonium acetate is volatile at low pressures. Because of this it has been used to replace cell buffers with non-volatile salts, in preparing samples for mass spectrometry.[3] It is also popular as a buffer for mobile phases for HPLC with ELSD detection for this reason. Other volatile salts that have been used for this include ammonium formate.

Food Additive[edit]

Ammonium acetate is also used as a food additive as an acidity regulator; INS number 264. It is approved for usage in Australia and New Zealand.[4]

Properties[edit]

CH3COONH4 is hygroscopic and decomposes easily to acetamide if heated above 165 °C.

CH3COONH4 → CH3C(O)NH2 + H2O

In this reaction, a salt is converted to two molecular species, which is a relatively uncommon conversion at mild temperatures. Further dehydration leads to acetonitrile or methyl cyanide, an important and wide used solvent.

Production[edit]

Ammonium acetate is produced by the neutralization of acetic acid with ammonium carbonate or by saturating glacial acetic acid with dry ammonia gas.[5] Obtaining crystalline ammonium acetate is difficult on account of its aqueous solution giving off ammonia when evaporated.

References[edit]

  1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. ^ a b c Sigma-Aldrich Co., Ammonium acetate. Retrieved on 2013-07-20.
  3. ^ Berman et al., 2008. J Am Soc Mass Spectrom, 19:1230-1236.
  4. ^ Australia New Zealand Food Standards Code "Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27. 
  5. ^ Brannt, William (1914). A practical treatise on the manufacture of vinegar. Lancaster, PA: Henry Carey Baird & Co. pp. 316–317. 

Further reading[edit]