Formate

Formate, also known as methanoate, is the conjugate base of formic acid. It is an anion (HCO−2) or its derivatives, such as esters of formic acid. The salts and esters of formate are generally colorless.

Fundamentals

When formic acid is dissolved in water, it converts to formate through the following reaction:

HCO2H → HCO−2 + H+

Formate is a planar anion, with the two oxygen atoms being equivalent and bearing a partial negative charge. The remaining C-H bond is not acidic.

Biochemistry

Formate is a common C-1 source in living systems, formed from various precursors including choline, serine, and sarcosine. It provides a C-1 source in the biosynthesis of some nucleic acids. Formate (or formic acid) is also involved as a leaving group in the demethylation of some sterols, catalyzed by aromatase enzymes using O2 as the oxidant.

Formate Esters

Formate esters have the formula HCOOR. Many form spontaneously when alcohols dissolve in formic acid. The most important formate ester is methyl formate, which is produced as an intermediate en route to formic acid. Methyl formate can be hydrolyzed to give formic acid and regenerate methanol. Formate esters often have distinctive odors and are less commonly used commercially due to their lower stability compared to acetate esters.

Formate Salts

Formate salts have the formula M(HCOO). These salts are prone to decarboxylation, which can be useful in certain applications. For example, hydrated nickel formate decarboxylates at about 200 °C with reduction of the Ni2+ to finely powdered nickel metal. Such fine powders are useful as hydrogenation catalysts.

Examples

Examples of formate esters and salts include ethyl formate, sodium formate, potassium formate, caesium formate, methyl formate, methyl chloroformate, triethyl orthoformate, trimethyl orthoformate, phenyl formate, and amyl formate.

Properties

The formate ion has a molecular structure of C(=O)[O-][5]. Its physical and chemical properties, such as boiling point, melting point, vapor pressure, and water solubility, are estimated using various models and experimental data[5]. The formate ion is also involved in various environmental processes, including atmospheric oxidation, soil adsorption, and bioaccumulation[5].

Citations:

[1] https://en.wikipedia.org/wiki/Formate

[2] https://pubchem.ncbi.nlm.nih.gov/compound/Formate

[3] http://www.chem.ucla.edu/~harding/IGOC/F/formic_acid.html

[4] https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/formate

[5] http://www.chemspider.com/Chemical-Structure.277.html