On the High-Pressure Solubilities of Carbon Dioxide in Several Ionic Liquids

Abstract

The solubility of carbon dioxide in nine ionic liquids (ILs), at 298 K, 313 K, and 333 K and pressures up to 9 MPa, is presented. The solubility of CO2 in the selected ILs increases with increasing pressure and decreases with increasing temperature, as expected. The effect of several different anions on the solubility of CO2 with a common 1-ethyl-3-methyl­imidazolium cation is studied in this work. The anions compared were hydrogen sulfate ([emim][HSO4]), methylsulfate ([emim][MeSO4]), methane sulfonate ([emim][MeSO3]), thiocyanate ([emim][SCN]), and diethylphosphate ([emim][DEP]). The results for 1-ethyl-3-methyl­imidazolium hydrogen sulfate are particularly interesting and can be explained based on the stronger attractive interactions between the IL and CO2, which is supported by quantum calculations. Other ILs investigated were ethyl(tributyl)phosphonium diethylphosphate ([P2444][DEP]), 1-hexyl-3-methyl­imidazolium trifluoromethane sulfonate ([hmim][OTf]), 1-(2-hydroxyethyl)-3-methyl­imidazolium trifluoroacetate ([OHemim][TFA]), and trihexyl tetradecyl­phosphonium bis(trifluoro­methyl­sulfonyl)imide ([P66614][Tf2N]). Using the new data for the [emim]+ ILs, in concert with data from the literature, these ILs were selected primarily to study the effect on the solubility of changing the cation. Of particular note is the high solubility of CO2 in the trihexyltetra­decyl­phosphonium based IL compared with its imidazolium equivalent. A brief discussion is presented to explain the observed solubility results.

Nitropyrene Photoprobes: Making Them, and What Are They Good for?

“…First investigations of the absorption of H 2 S with the IL [EMIM][MeSO 3 ] in our working group showed that the IL can also absorb H 2 S 60. It is also known from the literature that CO 2 dissolves in this IL and thus can be removed from natural gas by absorbing 61–63. In addition, it should also be explored if the drying performance of the IL [EMIM][MeSO 3 ] is reduced in the presence of H 2 S and CO 2 .…”

High-pressure solubility of carbon dioxide in pyrrolidinium-based ionic liquids: [bmpyr][dca] and [bmpyr][Tf2N]

“…The rational design of the corresponding absorption system suitable for industrial scale-up purposes will require a precise knowledge of the physical equilibrium between CO 2 and the ionic liquid. A vast number of experimental works in the literature deal with CO 2 solubility in various kinds of ionic liquids at different temperature and pressure conditions [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27].…”

A Thermodynamic Study of Aqueous 1‐Allyl‐3‐Methylimidazolium Formate Ionic Liquid as a Tailored Sorbent for Carbon Dioxide Separation

“…The CO 2 loadings in conventional imidazolium‐based [BF 4 − , PF 6 − , and bis(trifluoromethylsulfonyl)imide (Tf 2 N − )] and anion‐functionalized ILs are compared in Figure , and the results show that the physical absorption of CO 2 is the main contribution in these ILs and that the CO 2 loading in [Amim][HCOO] is the highest.…”

“…TheC O 2 loadings in conventional imidazolium-based [BF 4 À ,P F 6 À ,a nd bis(trifluoromethylsulfonyl)imide (Tf 2 N À )] and anion-functionalized ILs are compared in Figure 4, [22][23][24][25][26] and the resultss how that the physical absorption of CO 2 is the main contributioni nt hese ILs and that the CO 2 loading in [Amim][HCOO]i st he highest. [9] the water content in the vapor phase is very low and can be neglected for the CO 2 -H 2 Os ystemsu nder investigation.…”