formate

When dissolved in water, formic acid converts to formate:

:{{chem2|HCO2H -> HCO2- + H+}}

Formate is a planar anion. The two oxygen atoms are equivalent and bear a partial negative charge. The remaining C-H bond is not acidic.

:Image:Testosterone estradiol conversion.png

Formate is a common C-1 source in living systems. It is formed from many precursors including choline, serine, and sarcosine. It provides a C-1 source in the biosynthesis of some nucleic acids. Formate (or formic acid) is invoked as a leaving group in the demethylation of some sterols.{{cite journal |doi=10.1016/j.molmet.2019.05.012|title=Formate Metabolism in Health and Disease |year=2020 |last1=Pietzke |first1=Matthias |last2=Meiser |first2=Johannes |last3=Vazquez |first3=Alexei |journal=Molecular Metabolism |volume=33 |pages=23–37 |pmid=31402327 |pmc=7056922 }}

These conversions are catalyzed by aromatase enzymes using O₂ as the oxidant. Specific conversions include testosterone to estradiol and androstenedione to estrone.{{cite journal|author=Lephart, E. D.|title=A Review of Brain Aromatase Cytochrome P450|journal=Brain Res. Rev.|year=1996|volume=22|issue=1|pages=1–26|doi=10.1016/0165-0173(96)00002-1|pmid=8871783|s2cid=11987113}}

Formate is reversibly oxidized by the enzyme formate dehydrogenase from Desulfovibrio gigas:{{cite journal | doi = 10.1073/pnas.0801290105| title = Reversible interconversion of carbon dioxide and formate by an electroactive enzyme| date = 2008| last1 = Reda| first1 = Torsten| last2 = Plugge| first2 = Caroline M.| last3 = Abram| first3 = Nerilie J.| last4 = Hirst| first4 = Judy| journal = Proceedings of the National Academy of Sciences| volume = 105| issue = 31| pages = 10654–10658| doi-access = free| pmid = 18667702| pmc = 2491486}}

:{{Chem2|HCO2- -> CO2 + H+ + 2 e-}}

Formate esters have the formula HCOOR (alternative way of writing formula ROC(O)H or RO₂CH). 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. Methanol and carbon monoxide react in the presence of a strong base, such as sodium methoxide:

:{{chem2|CH3OH + CO -> HCOOCH3}}

Hydrolysis of methyl formate gives formic acid and regenerates methanol:

:{{chem2|HCOOCH3 -> HCOOH + CH3OH}}

Formic acid is used for many applications in industry.

Formate esters often are fragrant or have distinctive odors. Compared to the more common acetate esters, formate esters are less commonly used commercially because they are less stable.{{citation | doi = 10.1002/14356007.t11_t01 | chapter = Flavors and Fragrances, 2. Aliphatic Compounds | title = Ullmann's Encyclopedia of Industrial Chemistry | date = 2015 | last1 = Panten | first1 = Johannes | last2 = Surburg | first2 = Horst | pages = 1–55 | isbn = 978-3-527-30673-2 }} Ethyl formate is found in some confectionaries.

Formate salts have the formula M(O₂CH)(H₂O)_x. Such salts are prone to decarboxylation. For example, hydrated nickel formate decarboxylates at about 200 °C with reduction of the Ni²⁺ to finely powdered nickel metal:

:{{chem2|Ni(HCO2)2(H2O)2 -> Ni + 2 CO2 + 2 H2O + H2}}

Such fine powders are useful as hydrogenation catalysts.

File:Copper(II) formate hydrate.jpg

• ethyl formate, CH₃CH₂(HCOO)
• sodium formate, Na(HCOO)
• potassium formate, K(HCOO)
• caesium formate, Cs(HCOO); see Caesium: Petroleum exploration
• methyl formate, CH₃(HCOO)
• methyl chloroformate, CH₃OCOCl
• triethyl orthoformate
• trimethyl orthoformate, C₄H₁₀O₃
• phenyl formate HCOOC₆H₅
• amyl formate

{{Reflist}}

Category:Carboxylate anions

de:Formiate