Novel amino acid ionic liquids prepared via one-step lactam hydrolysis for the highly efficient capture of CO2

This article proposes for the first time the preparation of a series of amino acid ionic liquids (AAILs) via one-step hydrolysis of cheap lactams for the capture of CO 2 . The structures of the prepared AAILs are confirmed using NMR, FTIR, and ESI-MS, and their physical properties are also determined. It is found that these AAILs are reversible CO 2 absorbents with very high absorption capacities (0.15 to 0.18 g·g −1 at 313.2 K and 1.0 bar), better than almost all task-specific ionic liquids reported in literatures. The absorption mechanism is also elucidated to be a combination of 1:1 and 2:1 stoichiometric reaction of AAILs with CO 2 from NMR, FTIR, reaction equilibrium thermodynamical modeling and quantum calculations. The AAILs have the advantages of simple synthesis, high yield, and using available cheap raw materials. It is believed that this kind of AAILs have great potentials to be used as efficient CO 2 absorbents.