Solubilities and Diffusivities of Carbon Dioxide in Ionic Liquids:  [bmim][PF₆] and [bmim][BF₄]

Abstract

Gaseous carbon dioxide (CO 2 ) absorption measurements in l-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]) and l-n-butyl-3-methylimidazolium tetrafluoroborate ([bmim]-[BF 4 ]) were made using a commercial gravimetric microbalance at temperatures of 283.15, 298.15, 323.15, and 348.15 K and at pressures under 2 MPa. Gas solubilities were determined from absorption saturation (equilibrium) data at each fixed temperature and pressure. The experimental solubility data of CO 2 in ionic liquids have been successfully correlated for the first time using a simple cubic equation of state (EOS). Some phase behaviors of CO 2 and ionic liquid mixtures as well as Henry's law constants and the volume change of solutions are predicted well with the present EOS model. From time-dependent absorption data, binary diffusion coefficients of CO 2 in the ionic liquids have been obtained for the first time by the use of a simple diffusion model. Magnitudes in the observed diffusion coefficients are 10 -10 to 10 -11 m 2 s -1 , which are about 10-100 times lower than typical values, found in various organic liquids.

Solubilities of hydrofluorocarbons in ionic liquids: Experimental and modelling study

“…They used a generic Redlich-Kwong type of cubic EoS [30], with a modified van der Waals-Berthelot mixing rule and critical properties of ILs estimated by Vetere's 4 method [31]. Systems studied by this group include CO 2 in several different Ils [8][9][10][11][12], hydrofluorocarbons and hydrofluoroethers in some Ils [13][14][15][16], ammonia mixtures with Ils [17,18] [23], and H 2 S [24,25]. The authors present most of their results in graphical form and conclude that the model yields a good correlation of the experimental values.…”

Solubility of carbon dioxide and ethane in three ionic liquids based on the bis{(trifluoromethyl)sulfonyl}imide anion

“…The solubility of carbon dioxide in a variety of ILs has been determined at low pressures [1][2][3][4][5][6][7][8][9][10] and high pressures (up to 73 MPa) [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In particular, the system (carbon dioxide + [C 1 C 2 Im][NTf 2 ]), also investigated in this work, was studied by several authors [7][8][9][10]14,17].…”

Application of a Thermodynamic Consistency Test to Binary Mixtures Containing an Ionic Liquid

“…In the same way, Blanchard et al [1] and Aki et al [4] reported vapor-liquid equilibrium data for the system supercritical CO 2 + [bmim][NO 3 ]; Aki et al [4], Kroon et al [7] and Shiflett and Yokozeki [5] studied the system supercritical CO 2 + [bmim] [BF 4 ], while Shiflett and Yokozeki [8] and Shariati et al [6] presented data about the system supercritical CHF 3 + [bmim] [PF 6 ]. All these data show important discrepancies among the different sets.…”

“…Recently, Blanchard et al [1], Pérez-Salado Kamps et al [2], Liu et al [3] Aki et al [4], Shiflett and Yokozeki [5] and Shariati et al [6] measured the vapor-liquid equilibrium of the binary system supercritical CO 2 + [bmim][PF6] at different temperatures. In the same way, Blanchard et al [1] and Aki et al [4] reported vapor-liquid equilibrium data for the system supercritical CO 2 + [bmim][NO 3 ]; Aki et al [4], Kroon et al [7] and Shiflett and Yokozeki [5] studied the system supercritical CO 2 + [bmim] [BF 4 ], while Shiflett and Yokozeki [8] and Shariati et al [6] presented data about the system supercritical CHF 3 + [bmim] [PF 6 ].…”