Orthoformic acid or methanetriol is a chemical compound with the formula . In this molecule, the central carbon atom is bound to one hydrogen and three hydroxyl groups.
Orthoformic acid was long held to be a hypothetical chemical compound, as it was expected to decompose instantly into formic acid and water, making it too unstable to isolate or observe.[1] However, observation was shown to be possible in 2024, when it was identified by mass spectrometry. This involved the electron-irradiation of a frozen mixture of methanol and oxygen.[2]
See main article: Ortho ester. Methanetriol esters, known as orthoformates or ortho esters, are well known and commercially available.[3] [4] Like acetals, they are stable towards bases but easily hydrolyzed in acidic conditions to the alcohol and an ester of formic acid. They are used as mild dehydrating agents. Especially well known are trimethyl orthoformate, triethyl orthoformate, and triisopropyl orthoformate.