Fast and Efficient CO2 Absorption in Non-aqueous Tertiary Amines Promoted by Ethylene Glycol

With the catalytic induction of ethylene glycol (EG),anhydrousN,N-dimethylethanolamine (DMEA) shows CO2absorptionperformance via chemical binding and physical storage under normalpressure. Among the absorbents, pure DMEA and EG can hardlyabsorb CO2directly, but when the zwitterionic alkylcarbonates areformed between CO2and DMEA-EG, which can be characterized by13C NMR and FTIR spectroscopy, the absorption rate of CO2isimproved. With the increase in the CO2loading as the mass fraction ofEG in DMEA-EG, 80 wt % EG captures up to 0.72 mol/mol at 293 Kand 101 kPa via chemical binding and physical storage. The amountthat is chemically bound and physically stored is directly dependent ontemperature; within the range of 293-323 K, an absorption-regeneration cycle can be formed in a closed vessel because thezwitterion DMEA-EG-CO2is unstable at higher temperatures. In other words, DMEA-EG-CO2can be easily regenerated uponappropriate depressurization or heating. The corresponding thermodynamic calculations prove that the regenerative energy ofDMEA-EG-CO2is-27.33 kJ/mol, far less than that of other absorbent systems

Automated summary

With the catalytic induction of ethylene glycol, anhydrous N, N-dimethylethanolamine (DMEA) exhibits CO2 absorption performance. DMEA-EG can capture and regenerate CO2 through chemical binding and physical storage, forming an absorption-regeneration cycle within a certain temperature range.