Multi‐Molar Absorption of CO₂ by the Activation of Carboxylate Groups in Amino Acid Ionic Liquids

Abstract

Abstract A new strategy for multi‐molar absorption of CO 2 is reported based on activating a carboxylate group in amino acid ionic liquids. It was illustrated that introducing an electron‐withdrawing site to amino acid anions could reduce the negative inductive effect of the amino group while simultaneously activating the carboxylate group to interact with CO 2 very efficiently. An extremely high absorption capacity of CO 2 (up to 1.69 mol mol −1 ) in aminopolycarboxylate‐based amino acid ionic liquids was thus achieved. The evidence of spectroscopic investigations and quantum‐chemical calculations confirmed the interactions between two kinds of sites in the anion and CO 2 that resulted in superior CO 2 capacities.