Ammonium formate

Ammonium formate

Wet ammonium formate
Names
IUPAC name Ammonium formate
Other names Azanium formate
Identifiers
Jmol-3D images	Image
SMILES C(=O)O.N
Properties
Chemical formula	CH5NO2 NH4HCOO
Molar mass	63.06 g/mol
Appearance	White hygroscopic solid
Odor	Slightly ammoniac
Density	1.26 g/cm3
Melting point	116 °C (241 °F; 389 K)
Boiling point	180 °C (356 °F; 453 K) (decomposes)
Solubility in water	102 g / 100 ml (0 °C) 142.7 g / 100 ml (20 °C) 202.4 g / 100 ml (40 °C) 516 g / 100 ml (80 °C)
Solubility	Soluble in liquid ammonia, diethyl ether, ethanol, methanol Insoluble in acetone, benzene, chloroform, toluene
Thermochemistry
Std enthalpy of formation (ΔfHo298)	−556.18 kJ/mol
Hazards
Safety data sheet	ScienceLab
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	410 mg/kg (mice, intravenous)
Related compounds
Related compounds	Ammonium acetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium formate is an organic chemical compound, an ammonium salt of formic acid. It is a colorless, hygroscopic solid, with the chemical formula NH₄HCOO.

Properties

Chemical

Heating ammonium formate will cause it to convert it into formamide:

NH₄HCO₂ → HCONH₂ + H₂O

Further heating the formamide will cause it to decompose into carbon monoxide and ammonia, while at higher temperatures and in the presence of an acid catalyst will yield hydrogen cyanide:

HC(O)NH₂ → CO + NH₃

HC(O)NH₂ → HCN + H₂O

Ammonium formate can be used in the reductive amination of aldehydes and ketones, process known as Leuckart reaction.

One example is the conversion of acetone to isopropylamine:

HCOONH₄ + (CH₃)₂CO → (CH₃)₂HC-NH₂ + H₂O + CO₂

Physical

Ammonium formate is a hygroscopic white crystalline solid, soluble in water.

If wet ammonium formate is left to dry in a desiccator over the course of weeks or months, tiny white crystals of dry ammonium formate shaped like snowflake arms or fern leaves will form on the edge of the flask.

Availability

Ammonium formate is sold by big chemical suppliers, while smaller suppliers rarely have it in their stock.

Preparation

Ammonium formate can be made by bubbling ammonia through formic acid, though this requires lots of ammonia. An ammonium salt, such as ammonium bicarbonate can be used instead. Cooling the solution will cause the salt to precipitate. Excess water can be evaporated by carefully heating the solution, at below 115 °C, to prevent it from melting/decomposing. Filter the resulting precipitate and leave it to dry, either in open air or in a desiccator. Heating will not dry ammonium formate, instead it will decompose, resulting in a yellow syrup containing water, formamide and ammonium formate.

Since it's hygroscopic, it's best to keep it in a desiccator until you need it.

Projects

• Make formamide
• Make isopropylamine and other amines from ketones (Leuckart reaction)

Handling

Safety

Ammonium formate may release formic acid vapors and protection should be worn when handling the compound.

Storage

Ammonium formate should be kept in closed bottles, away from moisture. Can be stored in a desiccator. Ammonia may be added to limit hydrolysis.

Disposal

Mixing it with an alkali will neutralize it, though it's best to do this outside, as the reaction gives off ammonia.

References

Relevant Sciencemadness threads

• Does ammonium formate sublime?
• ammonium formate removal