High-Pressure Phase Behavior of Systems with Ionic Liquids:  Part V. The Binary System Carbon Dioxide + 1-Butyl-3-methylimidazolium Tetrafluoroborate

Abstract

The phase behavior of the binary system consisting of the supercritical fluid carbon dioxide (CO2) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) was studied experimentally. A synthetic method was used to measure its phase behavior. Bubble-point pressures of the system CO2 + [bmim][BF4] are reported for carbon dioxide concentrations ranging from (10.22 to 60.17) mole % and within a temperature range of (278.47 to 368.22) K. The CO2 + [bmim][BF4] binary system has a two-phase liquid−vapor region extending up to very high pressures. Most likely, the type of fluid-phase behavior is type III according to the classification of Scott and Van Konynenburg. The experimental results obtained were compared with the available phase behavior data of the binary system CO2 + 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF4]) to investigate the effect of the length of the alkyl group on the phase behavior of this type of system. A larger alkyl group leads to lower bubble-point pressures and, therefore, to higher solubilities of carbon dioxide in the imidazolium-based ionic liquid.

Modeling vapor liquid equilibrium of ionic liquids + gas binary systems at high pressure with cubic equations of state

“…The experimental data were taken from the literature Ren et al, 2010;Nwosu et al, 2009;Carvalho et al, 2009aCarvalho et al, , 2009bKroon et al, 2005;Liu et al, 2003;Ren and Scurto, 2009a;Shariati and Peters, 2003;Florusse et al, 2008) and the characteristics of these systems are shown in Table 2. The adjustable parameters, k ij and l ij , the %AARD and the range of experimental data utilized (expressed in pressure and liquid phase molar composition) are shown in Table 3 for all 17 binary systems analyzed here.…”

“…Phase equilibria in systems composed of ionic liquids + CO 2 were studied by several authors Ren et al, 2010;Nwosu et al, 2009;Carvalho et al, 2009aCarvalho et al, , 2009bKroon et al, 2005;Liu et al, 2003;Blanchard et al, 1999), but few of them have assessed the solubility in ionic liquids of other gases. The phase equilibria of different imidazolium ionic liquids with 1,1,1,2-tetrafluoroethane (R-134a) were studied by Scurto (2009a, 2009b); the authors emphasize the importance of understanding these systems for the separation of hydrofluorocarbon refrigerant gases and in other engineering applications.…”

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].…”

Transport Properties of Binary Mixtures of Carbon Dioxide and 1-Butyl-3-methylimidazolium Hexafluorophosphate Studied by Transient Grating Spectroscopy

“…1 Due to this unique character of the phase behavior, the system has potential applications for extraction or purification as a green solvent. The solubility of CO2 in various RTILs has been extensively studied [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and the structure of the binary mixture has been studied experimentally and theoretically. [18][19][20][21][22] On the other hand, reports on transport properties of these systems such as viscosity and diffusion are still limited in spite of their importance in designing chemical processes.…”