Thermodynamics and limiting activity coefficients measurements for organic solutes and water in the ionic liquid 1-dodecyl-3-methylimidzolium bis(trifluoromethylsulfonyl) imide

Abstract

Bio-fuels like alcohols, including butan-1-ol are produced from biomass by fermentation, and distillation. Ionic liquids (ILs) are novel attractive solvents, which can be used for removing butan-1-ol from the aqueous fermentation broth. In this work, the 1-dodecyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [DoMIM][NTf2] is proposed as an extractive solvent. The temperature of fusion and the enthalpy of fusion, obtained with DSC, the density and viscosity of [DoMIM][NTf2] as a function of temperature have been measured over a temperature range (298.15–368.15)K. The limiting activity coefficients γ13∞, for 65 solutes including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, tetrahydrofuran, ethers, and ketones in the [DoMIM][NTf2] were determined by gas–liquid chromatography at six temperatures from 318.15K to 368.15K. The partial molar excess Gibbs energies ΔG1E,∞, enthalpies ΔH1E,∞, and entropies ΔS1E,∞ at infinite dilution were calculated from the experimental γ13∞ values obtained over the temperature range. The gas-liquid partition coefficients, KL were calculated for all solutes and the Abraham solvation parameter model was discussed. The selectivity and capacity for butan-1-ol/water separation problem were calculated from γ13∞ and compared to literature values for bis{(trifluomethyl)sulfonyl}imide-based ILs with different cations and with all available data for ILs.