In chemistry, methanetetracarboxylate is a tetravalent anion with formula C5O84− or C(COO−)4. It has four carboxylate groups attached to a central carbon atom; so it has the same carbon backbone as neopentane. It is an oxocarbon anion, that is, consists only of carbon and oxygen.
The salts and esters are relatively uncommon, and their uses appear to be limited to chemical research. The sodium salt Na4C(COO)4 can be obtained by oxidation of pentaerythritol C(CH2OH)4 with oxygen in sodium hydroxide solution at pH 10 and about 60 °C, in the presence of palladium as a catalyst. The tetraethyl ester C(COO-C2H5)4 is traded as a specialty chemical and has been used in organic synthesis.
The anion can be seen as the result of removing four protons from methanetetracarboxylic acid, a hypothetical organic compound with formula C5H4O8 or C(COOH)4. However this acid has not been synthesised (as of 2009), and is believed to be unstable.
- Backer, H. J.; Lolkema, J. (1939), Methanetetracarboxylic esters. Recueil des Travaux Chimiques des Pays-Bas et de la Belgique, volume 58, pages 23–33.
- Japanese Patent 52128317, Sodium methanetetracarboxylate from pentaerythritol
- Armin de Meijere, Rafael R. Kostikov, Andrei I. Savchenko, Sergei I. Kozhushkov (2004), Diethyl Cyclopropylidenemalonate: Facile Preparation, Generation in situ, and Various Transformations. European Journal of Organic Chemistry, volume 2004 issue 19, Pages 3992–4002.