Separation of binary mixtures hexane/hex-1-ene, cyclohexane/cyclohexene and ethylbenzene/styrene based on limiting activity coefficients

摘要

The measurements of a limiting activity coefficients, gamma(infinity)(13) at infinite dilution for 63 solutes including wide spectra of alkanes, alkenes and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in the 1-(3-hydroxypropyl)pyridinium dicyanamide, [N-C3OHPY][DCA], determined by gas-liquid chromatography at temperature range of (298.15-368.15) K are developed. The synthesis and thermochemical characteristic of the ionic liquid (IL) is described. The density and viscosity of the IL was measured as a function of temperature in a range of (298.15-368.15) K. The comparison of gamma(infinity)(13) for selected solutes in ionic liquids (ILs) with [N-C3OHPY](+) cation and [TCM](-), [DCA](-), [TCB](-) and [SCN](-)-anions at one temperature, T= 328.15 K is shown. The gas-liquid partition coefficients, K-L at infinite dilution and the limiting fundamental thermodynamic functions, the partial molar excess Gibbs energy, enthalpy and entropy were calculated for all solutes. The values of selectivity and capacity for three separation problems hexane/hex-1-ene, cyclohexane/cyclohexene and methylbenzene/styrene were calculated from gamma(infinity)(13) and compared to literature values for [N-C3OHPY]-based or [DCA]-based ILs for the same separation problems. The data presented here shows that [N-C3OHPY][DCA] reveals large selectivity 2.34, 2.79 and 2.27 in three of discussed separation problems. However, the comparison to the measured earlier [DCA]-based ILs shows the low capacity for the hex-1-ene and cyclohexene. The Abraham salvation parameter model was also presented for all solutes. On the bases of the results the intermolecular interactions of the chosen IL and solutes was discussed. (C) 2017 Elsevier Ltd.