Carbon Dioxide Solubility in Phosphonium‑, Ammonium‑, Sulfonyl‑, and Pyrrolidinium-Based Ionic Liquids and their Mixtures at Moderate Pressures up to 10 bar

Carbon dioxide solubility in four ionic liquids (ILs) of different families with different cationic–anionic groups (tributylmethylphosphonium formate, butyltrimethylammonium bis­(trifluoromethyl sulfonyl) imide, 1-methyl-1-propylpyrrolidinium dicyanamide, and 1-ethyl-3-methylimidazolium acetate) at temperature of 298 K and a pressure range from vacuum to 10 bar were studied in this work using state of the art gravimetric sorption experiments. This work provides insight information regarding CO2 solubility for IL–IL mixing effect pressures up to 10 bar and at 298 K. Density values were used to calculate molar volume of ionic liquids for further discussions on CO2 solubility-molar volume relationship. Noticeably higher CO2 solubility with IL–IL hybridized systems of different family is opening a new window for research on a molecular level by simulations and intellectually designed ILs. Chemisorption behavior has been observed for the ILs that contain acetate-based anions in the structure and relevant discussion is included in this work.