Formate

Structure of formate

Formate (IUPAC name: methanoate) is the anion derived A formate (compound) is a salt or ester of formic acid.^[1]

Biochemistry[]

Formate is reversibly oxidized by the enzyme formate dehydrogenase from Desulfovibrio gigas:^[2]

${\displaystyle {\ce {COOH^- -> CO2 + H+ + 2 e-}}}$

Formate esters[]

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:^[1]

${\displaystyle {\ce {CH3OH + CO -> HCOOCH3}}}$

Hydrolysis of methyl formate gives formic acid and regenerates methanol:

${\displaystyle {\ce {HCOOCH3 -> HCOOH + CH3OH}}}$

Formic acid is used for many applications in industry.

Formate esters often are fragrant or have distinctive odors. Compared to the more common ethyl esters, formate esters are less commonly used commercially because they are less stable.^[3] Ethyl formate is found in some confectionaries.^[1]

Formate salts[]

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 to give finely powdered nickel metal:

${\displaystyle {\ce {Ni(COOH)2(H2O)2 -> Ni + 2 CO2 + 2 H2O + H2}}}$

Such fine powders are useful as hydrogenation catalysts.^[1]

Examples[]

Copper(II) formate hydrate

• 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
• HCOOC₆H₅

References[]