Solubility and diffusivity of hydrofluorocarbons in room‐temperature ionic liquids

Abstract

Gaseous absorption measurements of hydrofluorocarbons (trifluoromethane, difluoromethane, pentafluoroethane, 1,1,1,2‐tetrafluoroethane, 1,1,1‐trifluoroethane, and 1,1‐difluoroethane) in l‐n‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim][BF4]) were performed using a gravimetric microbalance at various isothermal conditions (temperatures between 283.15 and 348.15 K) and at pressures < 2 MPa. This report shows for the first time the solubility and diffusivity data for the hydrofluorocarbons in room‐temperature ionic liquids and surprisingly large differences in the solubility among the hydrofluorocarbons. Experimental gas solubility data were successfully correlated with well‐known solution models (Margules, Wilson, and NRTL activity coefficient equations). Diffusivities obtained from the time‐dependent absorption data were well analyzed using a diffusivity model developed in this study. The present solubility and diffusivity data are also compared with those of CO2, studied in our previous study. © 2005 American Institute of Chemical Engineers AIChE J, 2006

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

“…Tables 15 and 16 show the detailed results for the system CHF 3 + [bmim] [PF 6 ]. The data from Shiflett and Yokozeki [8] and Shariati et al [6] are not fully consistent. Table 16 shows that Shariati et al [6] report dew point data, where ionic liquid exists in the gas phase.…”

“…In Table 4, for the system CO 2 + [bmim] [BF 4 ], the data by Aki et al [4] show greater deviations from the data by Kroon et al [7] or Shiflett and Yokozeki [5]. In Table 5, for the system CHF 3 + [bmim] [PF 6 ], the data by Shariati et al [6] and Shiflett and Yokozeki [8] show the same values in the same pressure range, but the work by Shariati et al [6] presents data with high pressures. All these discrepancies can be mainly attributed to the different experimental techniques used to measure the solubility, to ionic liquid impurities, and also to ionic liquid degradation [14].…”

“…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.…”

“…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]. The interpolation method used in this work is discussed in appendix A.…”