Reversible systems based on CO2, amino-acids and organic superbases

A group of amino-acids from a chiral pool in combination with two organic superbases (DBU or TMG) and CO2 was used to prepare carbamate-based ionic liquids and molten salts. The compounds obtained were characterized by H-1 NMR, C-13 NMR, FTIR, solubility profiles in reference solvents and DSC thermal analysis, including their decomposition temperature evaluation, which permitted us to check the stability/reversibility of the carbamate based salts. It's possible to tune the temperature of CO2 release according to the superbase tested as cation and the characteristics of the side chains of the amino-acids. Moreover, it was possible to solubilize a considerable variety of these carbamate functionalized aminoacids in conventional solvents.