Fast and efficient CO2 absorption in non-aqueous tertiary amines promoted by ethylene glycol

Abstract

With the catalytic induction of EG, anhydrous DMEA shows CO absorption performance via chemical binding and physical storage under normal pressure. Among the absorbents, pure DMEA can hardly absorb CO directly but when the zwitterionic alkylcarbonates are formed between CO and DMEA-EG which can be characterized by C NMR and FTIR, the absorption rate of CO will be improved at this time. An increasing the CO loading as the mass fraction of EG in DMEA-EG, 90wt.% EG captures up to 0.72 mol/mol. The amount of chemically bound and physically stored is directly dependent on temperature, within the range of 293 to 323K, an absorption-regeneration cycle can be formed in a closed vessel because of the zwitterion DMEA-EG-CO is unstable at the higher temperature. In other words, DMEA-EG-CO can be easily regenerated upon appropriate depressurization or heating, corresponding thermodynamic calculations prove that the regenerative energy of DMEA-EG-CO is 25.49kJ/mol.