(372u) Eutectic Ionic Liquids for Efficient Gas Separation

Absorption of gases such as CO, CO₂ and SO₂ are highly important, because these gases threaten environment and people’s health. Thus, new absorbent materials that can efficiently, reversibly, and economically capture CO, CO₂ and SO₂ must be developed. Eutectic ionic liquids (EILs) are considered as the alternative absorbents for gas capture due to the unique properties of ionic liquids. Compared with the conventional ILs, EILs are more attractive in CO, CO₂ and SO₂ absorption in recent years.

In this work, a series of functionalized EILs with multi-site anions were developed for efficient and reversible CO, CO₂ and SO₂ absorption through cooperative interaction. These functionalized EILs contain nitrogen and oxygen atoms as active multi-sites in their anions. It was found that EILs with Cu(I), imide anions and pyridinolate anions are efficient for CO, CO₂ and SO₂ capture under low-concentration, respectively. To study the selectivity of SO₂/CO₂, the SO₂ absorption and CO₂ absorption were performed using EIL-based task-specific deep eutectic solvents. Thus, high absorption capacities, rapid absorption kinetics, and low absorption enthalpies could be obtained through preorganization and cooperation strategy. The absorption mechanisms were investigated by using IR, NMR, and DFT calculation. This new process using multi-site anion-functionalized EILs is also applicable to the capture of other gases such as CO and NO. This work was supported by the Natural Science Foundation of China (No. 22078294).

References

• Cui, K. Jiang, H. Liu, Y. Zhou, Z. Zhang, R. Zhang, H. Lu, Highly efficient CO removal by active cuprous-based ternary deep eutectic solvents [HDEEA][Cl] + CuCl + EG, Sep. Pruif. Technol., 2021, 274, 118985
• Cui, J. Liu, S. Lyu, H. Wang, Z. Li, R. Zhang, J. Wang, SO₂ absorption in highly efficient chemical solvent AChBr + Gly compared with physical solvent ChBr + Gly, J. Mol. Liq. 2021, 330, 115650.
• Cui, S. Lyu, H. Wang, Z. Li, R. Zhang, J. Wang Tuning the structure of pyridinolate-based functional ionic liquids for highly efficient SO₂ absorption, Fuel, 2021, 303, 121311.
• Cui, Quasi-chemisorption by Ionic Liquids Through Quasi-chemical Interaction, Encyclopedia of Ionic Liquids, 2021, DOI: 10.1007/978-981-10-6739-6_139-1
• Cui, S. Lyu, F. Zhang, H. Wang, Z. Li, Y. Li, J. Wang, Tuning Ionic Liquids with Functional Anions for SO₂ Capture through Simultaneous Cooperation of N and O Chemical Active Sites with SO₂, Ind. Eng. Chem. Res. 2020, 59, 21522-21529
• Cui, J. Liu, S. Lyu, H. Wang, Z. Li, J. Wang, Efficient and Reversible SO₂ Absorption by Environmentally Friendly Task-Specific Deep Eutectic Solvents of PPZBr + Gly, ACS Sustainable Chem. Eng. 2019, 7, 14236-14246.
• Cui, Y. Li, J. Liu, H. Wang, Z. Li, J. Wang, Tuning Environmentally Friendly Chelate-Based Ionic Liquids for Highly Efficient and Reversible SO₂ Chemisorption, ACS Sustainable Chem. Eng. 2018, 6, 15292-15300.
• Huang, G. Cui, Y. Zhao, H. Wang, Z. Li, S. Dai, J. Wang, Reply to the Correspondence on “Preorganization and Cooperation for Highly Efficient and Reversible Capture of Low-Concentration CO₂ by Ionic Liquids”, Angew. Chem. Int. Ed. 2019, 58, 386-389.