(134h) Computational Design of Reactive Ionic Liquids for CO2 Capture
The physical characteristics and wide chemical tunability of ionic liquids make them an attractive alternative to aqueous amines for energy-related CO2 separations. Most efforts to date to modify the solubility of CO2 in ionic liquids have involved adding reactive amine functionalities to the anion or cation, with mixed success. Here we describe our recent work to use first-principles simulations to design a novel class of ionic liquids, aprotic heterocyclc anions, or "AHAs," that react selectively, reversibly, and controllably with CO2. We examine trends in reactivity with AHA composition, and consider the electronics of AHA-CO2 binding that lead to the very wide range of accessible absorption energies and potentially interesting kinetic behavior. We consider the potential interferring effects of H2O on CO2 binding. Finally, we compare the CO2 chemistry of the anionic AHAs with isoelectronic, neutral carbenes, potentially suitable as absorbents in non-ionic-liquid applications. We demonstrate the feasibility of these heterocycles as a platform for a wide range of CO2 separations applications.