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

Abstract

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 ¹H NMR, ¹³C 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 amino-acids in conventional solvents.