(647c) The Effect of Tethering Strategies On the Surface Structure of Amine-Functionalized Ionic Liquids: Inspiration On the CO2 Capture

Amine-functionalized ionic liquids (ILs) are one of the most attractive and promising absorbents for CO₂ capture, because of its high performance and notable advantages over traditional organic amine absorbents. For ILs absorbing CO₂, it is of primary importance to study the structure and orientation of cations and anions at the interface, which presents a great impact on the surface properties and the transportation of CO₂ across the liquid-gas interface. However, despite a variety of cation/anion-tethered amine-functionalized ILs being reported, the choice of the tethering location of the amine group is often somewhat arbitrary and lacks enough consideration in the view of interface chemistry.

Therefore, this work focused on this problem and illustrated the significance of the tethering strategy of the amine functional group on the interfacial structure of ILs for the first time, by investigating the interfacial composition and orientation of cation-/anion-tethered amine-functionalized ILs through molecular dynamic simulation. The results showed that when the amine group is tethered to the cation, strong interaction between the amine group and anions results in a compact interfacial structure without the cation/anion enrichment. However, for amino acid-based ILs with an anion-tethered strategy, the amine group tends to have a higher preference in the outer layer of interface. Therefore, from the viewpoint of interfacial adsorption and transfer, the amine-functionalized ILs with an anion-tethering strategy is considered of great benefit for the CO₂ capture, especially when the amine group is on the terminal side of a relatively long alkyl chain.