High-pressure solubility of carbon dioxide in imidazolium-based ionic liquids with anions [PF6] and [BF4]

Abstract

The solubility of carbon dioxide in three ionic liquids (ILs) under supercritical fluid condition was measured at pressures up to 32 MPa and at temperatures of 313.15, 323.15, and 333.15 K in a high-pressure view cell. The imidazolium-derivative ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]), and 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF 4 ]) were employed in this research. The effects of pressure, temperature, nature of anion and cation as well as the water content on the solubility of CO 2 in the ILs were investigated experimentally. The solubility of CO 2 in the IL was higher for the ILs with longer cationic alkyl group and for the ILs with lower anion polarity. The lower the water content or the lower the temperature as well as the higher the pressure, the higher was the solubility of CO 2 .

High-pressure phase behavior of binary mixtures containing methylpyrrolidinium derivative ionic liquids and carbon dioxide

“…Many ionic liquids have been studied as new green chemicals because of their useful and unique properties, such as negligible vapor pressure, thermal stability, non-flammability, and good ionic conductivity [1]. Ionic liquids are not new, some of them have been known for many decades.…”

Measurement and prediction of phase behaviour for 1-alkyl-3-methylimidazolium tetrafluoroborate and carbon dioxide: Effect of alkyl chain length in imidazolium cation

“…They showed that the anion has a great effect on the solubility of CO 2 than the cation. However, the alkyl chain length in the imidazolium cation also seems to affect the solubility, as reported by Lim et al [3].…”

“…In general, the model exhibits a good correlation with the experimental results obtained. When temperature is increased, a simultaneous increase in pressure is required to dissolve a fixed amount of CO [2,3,5]. The experimental VLE data were correlated by the PR-EoS with quadratic mixing rules and the binary interaction parameters determined at three different temperatures are shown in table 5.…”

High-pressure phase behavior of CO2+1-butyl-3-methylimidazolium chloride system

“…Peters and co-workers [12][13][14][15] and Blanchard et al [16] have investigated the high-pressure phase behavior of an imidazoliumbased IL and CO 2 mixture. Maurer and co-workers [17], Shiflett et al [18], and other groups [19][20][21][22] have studied the phase behavior of CO 2 in different types of ILs. In contrast to the abundance of reports on CO 2 solubility in IL with [PF 6 ] and [BF 4 ] anions [12][13][14][15][16][17][22][23][24][25][26], information characterizing the solubility of CO 2 in an IL with the [Cl] anion seems relatively scarce to date.…”

“…Maurer and co-workers [17], Shiflett et al [18], and other groups [19][20][21][22] have studied the phase behavior of CO 2 in different types of ILs. In contrast to the abundance of reports on CO 2 solubility in IL with [PF 6 ] and [BF 4 ] anions [12][13][14][15][16][17][22][23][24][25][26], information characterizing the solubility of CO 2 in an IL with the [Cl] anion seems relatively scarce to date. In particular, CO 2 solubility in 1-butyl-3-methylimidazolium chloride ([bmim][Cl]) has not been reported even though this IL has important potential use in applications, such as a separating agent for azeotropic mixtures [27], synthesis in sc-CO 2 [28] and the dissolution of biomass [29].…”