On the spontaneous carboxylation of 1-butyl-3-methylimidazolium acetate by carbon dioxide

The formation of 1-butyl-3-methylimidazolium-2-carboxylate in the mixture of CO2 with 1-butyl-3-methylimidazolium acetate under mild conditions (298 K, 0.1 MPa) has been put in evidence in the liquid phase using Raman and infrared spectroscopy complemented by DFT calculations and NMR (1H, 13C, 15N) spectroscopy.