Enhanced CO2 Absorption in Organic Solutions of Biobased Ionic Liquids

Solutions of biobased ionic liquids (ILs) for recovering CO2 from industrial flue gas are investigated. Four CO2 task-specific choline-based amino acids ([Cho][AA]): Alanine, Glycine, and, for the first time, Proline and Serine are tested. The drawbacks related to the high viscosity of these ILs are limited by applying dimethyl sulfoxide (DMSO) as a solvent, which is chosen because it is a polar aprotic liquid with a low toxicity, low vapor pressure, and relatively low price. The choline-based amino acids synthesized in this study have good absorption capacities (up to 0.3 mol CO2/mol IL, with only 12.5 wt% IL in DMSO) that represent the best performance of CO2 task-specific IL solutions to date. These solutions are competitive due to their low cost, low environmental impact, easy processability (due to their low viscosity) and good regenerability for the production and storage of pure CO2.