Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6619182 | Fluid Phase Equilibria | 2018 | 44 Pages |
Abstract
Solubility data of carbon dioxide (CO2) in the two ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] and 1-butyl-3-methylimidazolium tetrachloroferrate [BMIM][FeCl4] at T = (273.15-413.15) K and pressures up to pâ¯=â¯4.5â¯MPa are presented. In addition to the experiments, a literature review was done to compare the new results with published solubility data. The measurements were carried out using an isochoric method which operates in decrements of ÎTâ¯=â¯20â¯K within the investigated temperature range and at selected four different pressure steps ranging from a pressure p of around 4.5â¯MPa to around 0.5â¯MPa. The solubility of CO2 decreases in both ionic liquids with increasing temperatures. Within the p,T-range investigated, CO2 displayed a solubility in [BMIM][BF4] from a mole fraction xâ¯=â¯0.0117 and a corresponding molality mâ¯=â¯0.0526â¯mol·kgâ1 at Tâ¯=â¯413.15â¯K and pâ¯=â¯0.417â¯MPa up to xâ¯=â¯0.4876 and mâ¯=â¯4.2094â¯molâ¯kgâ1 at Tâ¯=â¯293.15â¯K and pâ¯=â¯4.349â¯MPa. The corresponding values for the solubility in [BMIM][FeCl4] start at a mole fraction xâ¯=â¯0.0268 and a corresponding molality mâ¯=â¯0.0818â¯mol·kgâ1 at Tâ¯=â¯413.15â¯K and pâ¯=â¯0.443â¯MPa and end at xâ¯=â¯0.5126 and mâ¯=â¯3.1216â¯mol·kgâ1 at Tâ¯=â¯293.15â¯K and pâ¯=â¯4.478â¯MPa. At a constant temperature, CO2 is better soluble in [BMIM][FeCl4] than in [BMIM][BF4] and the mean value of the solubility difference related to mole fraction x over the pressure range investigated amounts to about 4% at Tâ¯=â¯273.15â¯K and monotonously increases to about 92% at Tâ¯=â¯413.15â¯K. Henry's law constant as well as derived thermodynamic properties, such as the Gibbs energy of solvation, the enthalpy of solvation, the entropy of solvation, and the heat capacity of solvation, were calculated and discussed regarding the solute-solvent molecular interactions.
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Authors
Javid Safarov, Christopher Sperlich, Aygul Namazova, Abilgani Aliyev, Dirk Tuma, Astan Shahverdiyev, Egon Hassel,