Ammonium formate, NH₄HCO₂, is the ammonium salt of formic acid

Formic acid

Formic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...

. It is a colorless, hygroscopic, crystalline solid

Solid

Solid is one of the three classical states of matter . It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a...

.

Uses

Pure ammonium formate decomposes into formamide

Formamide

Formamide, also known as methanamide, is an amide derived from formic acid. It is a clear liquid which is miscible with water and has an ammonia-like odor. It is used primarily for manufacturing sulfa drugs and synthesizing vitamins and as a softener for paper and fiber...

 and water when heated, and this is its primary use in industry. Formic acid can also be obtained by reacting ammonium formate with a dilute acid, and since ammonium formate is also produced from formic acid, it can serve as a way of storing formic acid.

Ammonium formate can also be used in palladium on carbon

Palladium on carbon

Palladium on carbon, often referred to as Pd/C, is a form of palladium used for catalysis. It is usually used for catalytic hydrogenations in organic chemistry...

 (Pd/C) reduction of functional groups. In the presence of Pd/C, ammonium formate decomposes to hydrogen, carbon dioxide, and ammonia. This hydrogen gas is absorbed onto the surface of the palladium metal, where it can react with various functional groups. For example, alkenes can be reduced to alkanes, or formaldehyde to methanol. Activated single bonds to heteroatoms can also be replaced by hydrogens (hydrogenolysis

Hydrogenolysis

Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes "lysis" by hydrogen. The heteroatom may vary, but it usually is oxygen, nitrogen, or sulfur. A related reaction is hydrogenation, where hydrogen is added to the molecule, without...

).

Ammonium formate can be used for reductive amination

Reductive amination

Reductive amination is a form of amination that involves the conversion of a carbonyl group to an amine via an intermediate imine...

 of aldehydes and ketones (Leuckart reaction

Leuckart reaction

The Leuckart reaction is the chemical reaction of ammonium salts of formic acid with aldehydes to form amines by reductive amination. The reaction is named after Rudolf Leuckart....

)

Ammonium formate can be used as a buffer in high performance liquid chromatography (HPLC

High-performance liquid chromatography

High-performance liquid chromatography , HPLC, is a chromatographic technique that can separate a mixture of compounds and is used in biochemistry and analytical chemistry to identify, quantify and purify the individual components of the mixture.HPLC typically utilizes different types of stationary...

), and is suitable for use with liquid chromatography/mass spectrometry (LC/MS). The pK_a

Acid dissociation constant

An acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions...

values of formic acid and the ammonium ion are 3.8 and 9.2, respectively.

Reactions

When heated, ammonium formate eliminates water, forming formamide. Upon further heating it forms to HCN and H₂O. A side reaction of this is the decomposition of formamide to CO and NH₃.