Harro Dittmar - Liquid-Liquid Phase Transition of Solutions of  Tetrabutyl ammonium Chloride in o-Xylene and Ethyl benzene:  Phasediagrams and Corresponding State Analysis

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      Publication Details (including relevant citation   information):

      “Liquid-liquid phase transition in the ionic solutions of   tetra-n-butylammonium chloride in o-xylene and ethylbenzene :   Phase diagrams and corresponding state analysis”, H. Dittmar, A.   Butka, V. R. Vale, W. Schröer, J. Mol. Liq. 145, 116 (2009)



      The phase diagrams of the liquid-liquid phase   transition of solutions of tetrabutyl ammonium chloride   (N4444Cl) in o-xylene and ethyl benzene are reported and   compared with the phase diagrams of solutions of other ionic   liquids (IL) with halide anions (trihexyl tetradecyl phosphonium   (P666   14+)chloride and bromide and   1-alkyl 3-methyl imidazolium (Rnmim+) chlorides) in   non-polar solvents as alkanes, arenes and   CCl4 and also with solutions of various 1-alkyl 3-methyl   imidazolium tetrafluoroborates (Rnmim+  BF4) in alcohols and water.   All phase diagrams have an upper critical solution point (UCSP)   and are consistent with the presumption of Ising criticality. For   the corresponding state analysis different choices for the   concentration variable are applied. Using the variables of the   model fluid of charged hard spheres in a dielectric continuum,   termed restricted primitive model (RPM) a systematic overview of   the critical properties of the mixtures is obtained. The critical   temperatures of the solutions in the non-polar solvents are in   the region of the RPM but somewhat smaller. They are very   similar, do not correlate with the dielectric constant of the   solvents but show a weak correlation with the boiling   temperatures of the solvents, indicating the influence of the   cohesion of the solvents on the phase separation driven by   Coulomb interactions. The critical concentrations, width of the   phase diagrams and the slope of the diameter are noticeable   different for the solutions in protic and aprotic solvents but   show no further systematic.


      Address (URL): http://www.sciencedirect.com/science/article/pii/S0167732208002493