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ACIDS > 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 ant venom.

Formula: CH2O2, IUPAC ID: Formic acid, Density: 1.22 g/cm³, Boiling point: 100.8 °C, Molar mass: 46.02538 g/mol, Melting point: 8.4 °C


A major use of formic acid is as a preservative and antibacterial agent in livestock feed. In Europe, it is applied on silage (including fresh hay) to promote the fermentation of lactic acid and to suppress the formation of butyric acid; it also allows fermentation to occur quickly, and at a lower temperature, reducing the loss of nutritional value. Formic acid arrests certain decay processes and causes the feed to retain its nutritive value longer, and so it is widely used to preserve winter feed for cattle.[citation needed] In the poultry industry, it is sometimes added to feed to kill E. coli bacteria. Use as preservative for silage and (other) animal feed constituted 30% of the global consumption in 2009.

Formic acid is also significantly used in the production of leather, including tanning (23% of the global consumption in 2009), and in dyeing and finishing of textile (9% of the global consumption in 2009) because of its acidic nature. Use as a coagulant in the production of rubber constituted in 2009 6% of the global consumption.

Formic acid is also used in place of mineral acids for various cleaning products,such as limescale remover and toilet bowl cleaner. Some formate esters are artificial flavorings or perfumes. Beekeepers use formic acid as a miticide against the tracheal mite (Acarapis woodi) and the Varroa mite.The use of formic acid in fuel cells is also under investigation.

Laboratory use

Formic acid is a source for a formyl group for example in the formylation of methylaniline to N-methylformanilide in toluene. In synthetic organic chemistry, formic acid is often used as a source of hydride ion. The Eschweiler-Clarke reaction and the Leuckart-Wallach reaction are examples of this application. It, or more commonly its azeotrope with triethylamine, is also used as a source of hydrogen in transfer hydrogenation.

Like acetic acid and trifluoroacetic acid, formic acid is commonly used as a volatile pH modifier in HPLC and capillary electrophoresis.

As mentioned below, formic acid may serve as a convenient source of carbon monoxide by being readily decomposed by sulfuric acid.