Separation of water/butan-1-ol mixtures based on limiting activity coefficients with phosphonium-based ionic liquid

Abstract

In the present work the limiting activity coefficients (γ13∞) for 64 solutes, including polar and non-polar solutes as alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in the tributyltetradecylphosphonium dodecylbenzenesulfonate, [P14,4,4,4][DBS] were determined by gas-liquid chromatography at six temperatures in range of (318.15–368.15) K. Density, ρ as a function of temperature, T for chosen ionic liquid, [P14,4,4,4][DBS] at pressure p=101kPa was measured. The gas-liquid partition coefficients, KL at infinite dilution and the fundamental thermodynamic functions, the limiting partial molar excess Gibbs energy, enthalpy and entropy were calculated. The values of selectivity and capacity for water/butan-1-ol separation problem were calculated from γ13∞ and compared to literature values for phosphonium-based or other selected ionic liquids for the same separation problem. The Abraham solvation parameter model was also presented for all solutes. On the bases of the results the intermolecular interactions of the chosen IL and solutes were discussed. The data presented here shows that [P14,4,4,4][DBS] reveals the best ever measured selectivity and capacity for the for water/butan-1-ol separation.