Ammonium acetate

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Ammonium acetate
Ammonium acetate bottle and sample.jpg
Names
IUPAC name
Ammonium ethanoate
Systematic IUPAC name
Ammonium acetate
Other names
Azanium acetate
Properties
CH3COONH4
C2H7NO2
Molar mass 77.08 g/mol
Appearance Deliquescent white solid
Odor Acetic
Density 1.17 g/cm3 (20 °C)
1.073 g/cm3 (25 °C)
Melting point 110–114 °C (230–237 °F; 383–387 K) (Decomposes)
Boiling point 117.1 °C (242.8 °F; 390.2 K) (At 760 mmHg, decomposes)
102 g/100 mL (0 °C)
148 g/100 mL (4 °C)
143 g/100 mL (20 °C)
533 g/100 mL (80 °C)
Solubility Reacts with strong acids
Soluble in acetone, ammonia, ethanol, sulfur dioxide
Solubility in dimethylformamide 0.1 g/100 g
Solubility in methanol 7.89 g/100 ml (15 °C)
131.24 g/100 ml (94.2 °C)
Thermochemistry
−615 kJ/mol
Hazards
Safety data sheet ScienceLab
Flash point 136 °C
Lethal dose or concentration (LD, LC):
386 mg/kg (mice, intravenous)
Related compounds
Related compounds
Ammonium formate
Except where otherwise noted, 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 NH4CH3COO (sometimes written as CH3COONH4).

Properties

Chemical

Ammonium acetate decomposes at temperatures above 165 °C to yield acetamide:

CH3COONH4 → CH3C(O)NH2 + H2O

If acetamide is heated further, in the presence of a drying agent, it will convert to acetonitrile (methyl cyanide).

Physical

Ammonium acetate is a white hygroscopic solid. Ammonium acetate is volatile at low pressures and has a vinegar-like smell.

Availability

Ammonium acetate can be purchased online cheaply.

Preparation

Ammonium acetate can be prepared by reacting acetic acid with ammonia, ammonium bicarbonate or carbonate. Drying the solution by boiling the excess water is difficult, as ammonium acetate will decompose if the temperature is uneven. Heating the solution on a water bath at below 90 °C is an option, though a bit of ammonium acetate will decompose, causing the solution to darken. This isn't much of a problem, as the contamination will not precipitate when recrystallizing the acetate from the solution, and can be removed by vacuum filtering the crystals and wash them with cold water or acetone.

The best way to synthesize ammonium acetate, with insignificant product loss, is to bubble ammonia gas into anhydrous (glacial) acetic acid, which causes the ammonium acetate to crystallize and crash out of the acetic acid. Filter the wet crystals and sir dry them. While attractive, this method relies on using gaseous ammonia which means you'll need a more complicated system, than simply dumping an ammonium salt in acetic acid.

Projects

Handling

Safety

Ammonium acetate is non-toxic, though if heated it can generate acetamide which is considered carcinogenic.

Ammonium acetate is hygroscopic and will slowly hydrolyze to yield acetic acid, which is irritant and corrosive in large quantities.

Storage

Ammonium acetate should be stored in dry sealed containers, as it's hygroscopic.

Disposal

Ammonium acetate is a harmless source of nitrogen to organic life and can be discarded without any special treatments.

References

Relevant Sciencemadness threads