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

Abstract

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 1ethyl-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 CO 2 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 CO 2 solubility-molar volume relationship. Noticeably higher CO 2 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.

Temperature and Composition Dependence of the Thermodynamic Properties of an Aqueous Solution of 1-Ethyl-3-methylimidazolium Formate and 1-Ethyl-3-methylimidazolium Acetate

“…To the best of our knowledge, no data is presented pertaining to the density of [EMIM]­[HCOO]. In the opened literature, there are a few density data for pure [EMIM]­[CH 3 COO] − and its aqueous solution. ,, Figure shows the relative deviations between the data measured in this work and the literature results for pure [EMIM]­[CH 3 COO].…”

“… a Standard uncertainties u are u (ρ) = 5 × 10 –4 g·cm –3 , u ( T ) = 0.01 K, and u ( p ) = 3 kPa. b Reference . c Reference . d Reference . e Reference . f Reference . g Reference . h Reference . i Reference . j Reference . k Reference . l Reference . m Reference . n Reference . o Reference . p Reference . …”

“…The experimental VLE data for the [EMIM]­[CH 3 COO] aqueous solution has been compared to those presented by Römich et al . and Guo et al The comparison of liquid density of pure [EMIM]­[CH 3 COO] − and its binary system with water ,, is also presented and discussed. To the best of our knowledge, there is no data for aqueous solution of [EMIM]­[HCOO] for comparison.…”

Gas Solubility and Rheological Behavior of Natural Deep Eutectic Solvents (NADES) via Combined Experimental and Molecular Simulation Techniques

“…They have almost null vapor pressure and can be custom‐tailored for various purposes concerning polarity and selectivity for different applications . Due to their physical and chemical properties, ILs could be modified and improved by both their anionic and cationic fractions and they serve a wide range of applications including chemical or enzymatic reactions,, biocatalytic process, extraction solvent, electrochemical applications, CO 2 capture, olefin paraffin separation and biomedical applications . Despite ILs advantages and wide application potential, in recent years its “greenness” has often been questioned and challenged due to various reasons including limited or poor biodegradability, biocompatibility, sustainability, toxicity, combustible character, unfavorable physical property (e. g. viscosity) and high production cost at bulk quantities …”

“…Due to their negligible vapor pressure, and less corrosive nature ILs are considered as a viable alternatives for CO 2 scrubbing in the recent years, being tested both as pure compounds and as mixtures . The high solubility of CO 2 in ILs has been considered one of the most promising options for developing CO 2 capture methods, mainly considering the possibility of designing specific ionic combinations with suitable properties for either pre‐ or post‐ combustion CO 2 capture processes ,. The tailor made structure of ILs allows the design of task‐specific characteristics of ILs as sorbents, even more remarkable considering the large amount of anion‐cation combinations leading to room temperature IL ,.…”