Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Systematic investigations on the liquid-liquid phase behavior of binary mixtures of ionic liquids (IL) of the type 1-alkyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (CxmimNTf2, x = 2, 4, 6, 8, and 10) with n-heptanol and its branched isomers 3-ethyl-3pentanol and 2,4-dimethyl-3-pentanol have been performed. The phase diagrams were determined at atmospheric pressure in the temperature range of T = (263 - 448) K by applying the cloud-point method. The phase diagrams are analyzed in terms of well established numerical concepts basing on Ising criticality. The results are discussed, and trends and explanations for the shifts of the range of solubility are given. The systems show partial miscibility with upper critical solution temperatures. Comparing the solutions in branched alcohols with those in the linear isomer the critical solution points are found to be remarkably shifted towards higher temperatures and lower IL-content. The trend becomes more pronounced for ILs with shorter alkyl side chain where also a change of the shape of the phase diagrams is observed.