On the Existence of the Elusive Monomethyl Ester of Carbonic Acid [CH₃OC(O)OH] at 300 K: ¹H‐ and ¹³C NMR Measurements and DFT Calculations

The elusive monomethyl ester of carbonic acid [CH 3 OC(O)OH] has been prepared at 300 K by protonation of the sodium salt NaOC(O)OCH 3 with anhydrous HCl or water and characterized by 1 H‐ and 13 C NMR spectroscopy. The stability of the acid and its reactivity towards hydroxo ions and methylating agents under ambient conditions are discussed. The energetics and the mechanism of the investigated reactions are examined on the basis of density functional calculations. For kinetic and thermodynamic reasons CH 3 OC(O)OH is unlikely to be formed by insertion of CO 2 into the O–H bond of methanol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)