Liquid-Liquid Equilibria of 1-Butanol/Water/IL Systems

The liquid-liquid equilibria (LLE) of ternary 1-butanol/water/ionic liquid (IL) mixtures were measured and predicted. The LLE data were measured for ternary mixtures containing 1-butanol, water, and one of the following ILs: 1-decyl-3-methylimidazolium tetracyanoborate ([Im(10.1)](+)[tcb](-)), 4-decyl-4-methylmorpholinium tetracyanoborate ([Mo-10.1](+)[tcb](-)), 1-decyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide ([Im(10.1)](+)[ntf(2)](-)), and 4-decyl-4-methylmorpholinium bis-(trifluoromethylsulfonyl)imide ([Mo-10.1](+)[ntf(2)](-)). The LLE data were determined at atmospheric pressure for two different temperatures (308.15 and 323.15 K). To evaluate the application of the ILs studied to the extraction of 1-butanol from aqueous solutions, the 1-butanol distribution coefficients and selectivities were determined from the data. The perturbed-chain statistical associating fluid theory (PC-SAFT) was used for modeling. Previously published pure-component PC-SAFT parameters for the ILs [J. Phys. Chem. B 2013, 117 (11), 3173-3185] were used for this purpose. The binary interaction parameters for 1-butanol/IL pairs were set to zero. The binary interaction parameters for 1-butanol/water and water/IL pairs were determined by fitting to the respective binary LLE data at various temperatures. Without introducing any additional parameters or refitting existing PC-SAFT parameters, the liquid-liquid equilibria of the ternary 1-butanol/water/IL mixtures were predicted and exhibited good agreement with the experimental data. Moreover, the very sensitive property distribution coefficient and the selectivity of 1-butanol were accurately predicted.