Solubility of CO₂ in the Ionic Liquid [bmim][PF₆]

Abstract

New experimental results are presented for the solubility of carbon dioxide in the ionic liquid 1-N-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]) for temperatures from (293 to 393) K and pressures up to about 9.7 MPa. Solubility pressures are correlated by means of the extended Henry's law.

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

“…In Table 2 and Fig. (1), for the CO 2 + [bmim] [PF 6 ] system, the data determined by Blanchard et al [1], Liu et al [3] and Aki et al [4] show greater deviations from the data by Pérez-Salado Kamps et al [2] or Shariati et al [6]; the discrepancies become even more significant with increasing pressure at constant temperature. In Table 3, for the system CO 2 + [bmim] [NO 3 ], the data by Blanchard et al [1] present a lower solubility of CO 2 than those by Aki et al [4].…”

“…The same procedure is applied for the data at 323.15 and 333.15 K, as shown in Tables 9 and 10, respectively; both of data sets are not fully consistent. Tables 11 and 12 present detailed results for the data from Pérez-Salado Kamps et al [2], at 313.15 and 333.15 K, respectively; these data are thermodynamically consistent, meaning that all the deviations are within the defined ranges, -20% to 20%; however, in both tables the last point has a high probability to be inconsistent, because the two % P i < 5 yields % A i greater than 10. Tables 13 shows the [5] are thermodynamic consistent; in this latter, there is a high probability of inconsistency in the data point x 1 = 0.002, because is the sole data point with % P = 11.94, slightly out of the limits.…”

“…For the binary mixtures CO 2 + ionic liquid, the concentration of the ionic liquid in supercritical CO 2 is so small that it could not be detected with experimental equipment [1][2][3][4][5][6][7]. On the other hand, for the binary mixtures CHF 3 + ionic liquid, the concentration of the ionic liquid in supercritical CHF 3 is appreciable [6,8] [17,18].…”

“…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 ].…”

“…The fitting of the experimental data requires the calculation of some model parameters using a defined objective function that must be optimized. The test was first validated with the binary system CO 2 + n-butane, and next applied to the binary systems CO 2 4 ] is miscible in water. Table 1 presents some properties of the components of the binary mixtures included in this work.…”