Orthoacetic acid or ethane-1,1,1-triol is an hypothetical organic compound with formula or H<sub>3</sub>C-C(OH)<sub>3</sub>. It would be an ortho acid with the ethane backbone.
Orthoacetic acid is believed to be impossible to isolate, since it would readily decompose into acetic acid and water. It may have a fleeting existence in aqueous solutions of acetic acid.
The three hydroxyls of CH<sub>3</sub>C(OH)<sub>3</sub> could be deprotonated, leading successively to CH<sub>3</sub>C(OH)<sub>2</sub>(O<sup>âÂÂ</sup>) (dihydrogenorthoacetate), CH<sub>3</sub>C(OH)(O<sup>âÂÂ</sup>)<sub>2</sub> (hydrogenorthoacetate), and finally CH<sub>3</sub>C(O<sup>âÂÂ</sup>)<sub>3</sub> (orthoacetate).
There are many stable organic compounds with the trivalent moiety H<sub>3</sub>CC(OR)<sub>3</sub>, which are formally esters of orthoacetic acid and called orthoacetates. They include trimethyl orthoacetate and triethyl orthoacetate, which are commercially available.