Ammonium formate
[CAS# 540-69-2]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Inorganic ammonium salt
• Name: Ammonium formate
• Synonyms: azanium formate
• Molecular Formula: NH₄^.CHO₂
• Molecular Weight: 63.06
• CAS Registry Number: 540-69-2
• EC Number: 208-753-9
• SMILES: C(=O)[O-].[NH4+]

Properties

• Density: 1.26 g/mL (Expl.)
• Melting point: 119-121 ºC (Expl.)
• Boiling point: 180 ºC (760 mmHg) (decomp.) (Expl.)
• Water solubility: soluble 143% w/w (20 ºC) (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Skin corrosion	Skin Corr.	1B	H314

Discovory and Applicatios

Ammonium formate, with the chemical formula NH₄HCO₂, is a simple ammonium salt that has gained significant attention in scientific and industrial applications. This substance was discovered in the 19th century as chemists explored salts of organic acids. Ammonium formate stands out for its mild acidic properties and its decomposition into non-toxic byproducts, making it a valuable compound in various chemical reactions and applications. The salt is typically a white, odorless solid that is highly soluble in water, making it easy to handle and integrate into solutions for diverse purposes.

One of the most important applications of ammonium formate is in organic synthesis, where it is used as a versatile reducing agent. This role is especially notable in the field of catalytic transfer hydrogenation, a process in which ammonium formate serves as a hydrogen donor. Under mild conditions and in the presence of a suitable catalyst, such as palladium on carbon, ammonium formate can effectively reduce carbonyl compounds, nitro compounds, and other unsaturated bonds without the need for high pressures or temperatures. This reaction is highly valued for synthesizing pharmaceutical compounds and fine chemicals, as it provides a safer and more cost-effective alternative to using molecular hydrogen gas.

Ammonium formate is also extensively used in analytical chemistry, particularly in mass spectrometry. In this context, it functions as a buffer component in liquid chromatography-mass spectrometry (LC-MS) applications. Ammonium formate helps to stabilize pH and improve ionization efficiency, leading to better peak resolution and more accurate results. Its non-volatile decomposition products reduce potential contamination of instruments, thus providing high-quality data. This makes ammonium formate a preferred choice for analyzing small molecules, peptides, and other compounds in complex biological and chemical mixtures. Its compatibility with various mass spectrometric techniques contributes to its popularity in bioanalytical research and quality control labs.

In the biochemical and pharmaceutical industries, ammonium formate also finds use in deprotecting amino acids and peptides. During peptide synthesis, certain groups are protected to prevent unwanted reactions, and ammonium formate is employed to remove these protecting groups without damaging sensitive peptide bonds. This selective reactivity is particularly advantageous in synthesizing complex biomolecules, where precision is critical for maintaining structure and function. Ammonium formate’s gentle action on sensitive biomolecules makes it a go-to reagent in laboratories involved in peptide synthesis and protein engineering.

Another application of ammonium formate is in the agriculture industry, where it serves as a nitrogen source in fertilizers. Due to its high nitrogen content, it is sometimes used as a supplement to improve soil fertility and promote plant growth. It provides a rapid nitrogen release compared to other fertilizers, making it effective for short-term crop needs. However, its application in agriculture is relatively limited because of its solubility and hygroscopic nature, which can make it less stable under certain conditions.

Ammonium formate also shows promise in fuel cell technology, particularly in hydrogen storage. Since it decomposes into hydrogen gas and carbon dioxide under heat, researchers are investigating its potential for hydrogen generation in portable fuel cells. This property could make ammonium formate a useful component in the development of cleaner, more efficient energy systems. While still in the experimental stage, the potential for ammonium formate to serve as a safe hydrogen source is an exciting area of research in sustainable energy.

Though generally safe, ammonium formate must be handled with caution due to its reactivity with strong acids and bases. In safe, controlled conditions, it remains a highly useful reagent that continues to serve a wide range of scientific, industrial, and agricultural applications.

References

1997. Determination of naringin and naringenin in human urine by high-performance liquid chromatography utilizing solid-phase extraction. Journal of chromatography. B, Biomedical sciences and applications, 698(1).
DOI: 10.1016/s0378-4347(97)00474-x