The Solubility of Carbon Dioxide and Density for Binary Mixtures of 1-Butyl-3-methylimidazolium Acetate and 1-Butyl-3-methylimidazolium Tetrafluoroborate (original) (raw)
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The Journal of Chemical Thermodynamics, 2019
Design of suitable solvent is important to separate CO 2 from natural gas. Ionic liquids, known as ''green solvents", are proper alternatives for conventional solvents in gas sweetening process. In this work, the abilities of ionic liquids 1-butyl-3-methylimidazolium acetate ([Bmim][Ac], 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF 4 ]) and their binary mixtures are experimentally investigated for CO 2 separation from CH 4. The solubility of CO 2 /CH 4 mixtures (25/75 mol%, 50/50 mol% and 75/25 mol%) in ionic liquids [Bmim][Ac], [Bmim][BF 4 ] and their binary mixtures containing {75 w% [Bmim][Ac] + 25 w% [Bmim][BF 4 ], 50 w% [Bmim][Ac] + 50 w% [Bmim][BF 4 ] and 25 w% [Bmim][Ac] + 75 w% [Bmim][BF 4 ]} are measured at (298.15, 308.15 and 318.15) K for pressures up to 5.0 MPa. The ideal and real CO 2 /CH 4 solubility selectivities for the studied ionic liquids are also reported. Finally, the cubic plus association (CPA) equation of state has been applied to predict the experimental solubilities.
Chemical Engineering Research and Design, 2019
Highlights: Thermo-physical properties of individual ionic liquids (ILs) and their binary mixtures Ionic liquids tested: choline octanoate ([Ch][Oct]), 1-methyl-3-octylimidazolium trifluoromethanesulfonate ([Omim][Otf]), and 1-methyl-3-octylimidazolium chloride ([Omim][Cl]) CO2 gas absorption in ionic liquids (ILs) and their binary mixtures Density and thermo-gravimetric measurements of ionic liquids (ILs) and their binary mixtures Effect of different anions [Otf-, Cl-] and different cation groups [Omim, Ch] on the gas absorption potential of ILs Comparison of CO2 sorption results at 298.15 K with experimentally measured methane (CH4) and nitrogen (N2) data
Gas Solubilities in Room-Temperature Ionic Liquids
Industrial & Engineering Chemistry Research, 2004
The solubility of CO 2 , CH 4 , N 2 , and CO was measured in a broad number of ionic liquids using a pressure drop setup. A successful correlation of the Henry's law constants at 60 • C was made to two empirical models already described in literature (Camper et al. [13] and Moganty and Baltus [25]). Subsequently, a new empirical model was proposed, which describes the Henry's law constant as a function of the molar mass of the ionic liquid, as long as physical interactions between gas and ionic liquid are dominant. Additionally, the entropy and enthalpy of solvation was studied by means of the temperature influence to the Henry's law constant.
Journal of Chemical & Engineering Data, 2011
The physicochemical properties (density, viscosity, and carbon dioxide solubility) of ionic liquids based on pyridinium, pyrrolidinium, and ammonium cations were studied at atmospheric pressure and as a function of temperature between (293 and 343) K. The influence of the inclusion of oxygen functional groups (hydroxyl and ester) in the cations was assessed by comparing their behavior with that of similar nonfunctionalized ionic liquids. We observed that the presence of oxygen groups does not affect the density significantly. The inclusion of an ester group in the alkyl-side chain of pyridinium or ammonium cations greatly increases the viscosity of bis(trifluoromethylsulfonyl)imide ionic liquids (5 times for pyridinium, 2 times for ammonium-based ionic liquids at 293 K), while the presence of hydroxyl groups only slightly increases their viscosity (16 % increase for ammonium at 293 K). Carbon dioxide solubilities are not significantly influenced by the introduction of oxygen functional groups in the cations for the ammonium-based ionic liquids. In the case of the pyridinium-based ionic liquids, the solubility of carbon dioxide significantly decreases (up to a 48 % decrease in mole fraction) due to a defavorable entropic contribution to the Gibbs energy of solvation.
New experimental results are presented for the solubility of carbon dioxide, hydrogen sulfide in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) at temperatures range from (303.15 to 353.15) K and pressures up to about 2 MPa. The solubility of the mixture of CO2/H2S in [C8- mim][PF6] under various feed compositions were also measured at temperatures of (303.15, 323.15 and 343.15) K and the pressure up to 1 MPa. The solubility of carbon dioxide and hydrogen sulfide increased with increasing pressure and decreased with increasing temperature and the solubility of H2S is about three times that of CO2 in the particular ionic liquid studied. The measured data were correlated using extended Henry’s law included Pitzer’s virial expansion for the excess Gibbs energy, and the generic Redlich–Kwong cubic equation of state proposed for gas/ionic liquid systems. The correlations from the two models show quite good consistency with the experimental data for CO2/IL and H2S/IL binary mixtures within experimental uncertainties. For CO2/H2S/IL ternary mixtures, the RK model shows better correlation with the experimental values. We also studied the effect of cation alkyl chain length on the CO2 and H2S solubility by comparison of the experimental data of this study with those of previous reports. As the cation alkyl chain length became longer, the solubility of CO2 and H2S increased in the ionic liquid. Additionally, the influence of the anion on the solubility is studied by comparing the solubility of CO2 and H2S in [C8mim][PF6] with those in [C8mim][Tf2N]. As a result, CO2 and H2S have higher solubility in the IL with [Tf2N] as the anion.
Solubilities and thermophysical properties of ionic liquids
Pure and Applied Chemistry, 2000
This report presents the systematic study on the solubilities of 1-alkyl-3-methylimidazolium hexafluorophosphate [e, or bmim][PFThe data were correlated by means of the UNIQUAC and modified nonrandom two-liquid (NRTL) equations utilizing parameters derived from the solid–liquid equilibrium (SLE). The root-mean-square deviations of the solubility temperatures for all calculated data depend on the particular system and the equation used.The solubilities of [C
Solubility of CO2 in the Ionic Liquids [bmim][CH3SO4] and [bmim][PF6]
Journal of Chemical & Engineering Data, 2006
A high-pressure view-cell technique based on the synthetic method was used to determine the solubility of carbon dioxide in the ionic liquid 1-n-butyl-3-methylimidazolium methyl sulfate ([bmim][CH 3 SO 4 ]). The temperature ranged from 293.2 K to 413.1 K, the pressure and the carbon dioxide molality reached up to ∼10 MPa and ∼3.3 mol of CO 2 ‚(kg of [bmim][CH 3 SO 4 ])-1 , respectively. The (extended) Henry's law was successfully applied to correlate the solubility pressures. The final results for the Henry's constant (at zero pressure) of carbon dioxide in [bmim][CH 3 SO 4 ] (on the molality scale) are correlated within the estimated uncertainty ((1.3 %) by ln(k H,CO 2 (0) /MPa)) 7.2738-1775/(T/K)-0.002033(T/K). Furthermore, some small corrections were applied to the experimental results for the solubility of carbon dioxide in the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]) reported in previous work. The corrected values for the Henry's constant of carbon dioxide in [bmim][PF 6 ] only slightly and systematically deviate (by about-2 % at given temperature) from the values reported previously.
The Journal of Chemical Thermodynamics, 2013
The solubility of different gases (carbon dioxide, methane, ethane, carbon monoxide and hydrogen) in ionic liquids with an alkyl sulfate anion has been modeled with the Group Contribution equation of state developed by Skjold-Jørgensen. New gas solubility measurements have been carried out with a high pressure magnetic suspension balance in order to cover pressure and temperature ranges not considered in previous studies and to obtain more experimental information for the correlation of parameters of the equation of state. New solubility measurements include the solubility of carbon dioxide in 1-ethyl 3-methyl imidazolium ethyl sulfate [emim][EtSO 4 ] at temperatures of 298 K and 348 K and pressures ranging from 0.3 MPa to 6.5 MPa, the solubility of methane in [emim][EtSO 4 ] at a temperature of 293 K and pressures ranging from 0.2 MPa to 10.2 MPa, and the solubility of ethane in [emim][EtSO 4 ] at temperatures of 323 K and 350 K and pressures ranging from 0.2 MPa to 4 MPa. Results show that the Group Contribution equation of state can be used to describe the solubility of gases in alkyl sulfate ionic liquids as well as infinite dilution coefficients of alkanes in the ionic liquids, with average deviations between experiments and calculations ranging from 1% to 10% in the case of mixtures with CO 2 , CO, CH 4 and H 2 with the alkyl sulfate ionic liquids to up to 34% in the case of the solubility of ethane in [emim][EtSO 4 ].