Fluid-phase behavior of {1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, [C6mim][NTf2], plus C2-C8 n-alcohol} mixtures:: Liquid-liquid equilibrium and excess volumes

In the frame of the IUPAC Project entitled Thermodynamics of ionic liquids, ionic liquid mixtures, and the deVelopment of standarized systems, 1- hexyl- 3- methylimidazolium bis( trifluoromethylsulfonyl) imide, [C(6)mim][ NTf2], was selected as the model ionic liquid to perform round-robin measurements on a series of ionic liquid properties. In this work, the temperature- composition liquid-liquid equilibria of this ionic liquid with linear alkan-1- ols, CnH(2(n)+ 1) OH, with n) 4, 5, 6, and 8, were determined at a nominal pressure of 0.1 MPa and up to 50 MPa for n) 4, 5, and 6. Excess molar volumes, V-E, of mixtures of this same ionic liquid with linear alkan1- ols, CnH(2n+1)OH, with n ranging from 2 to 5, were measured at a nominal pressure of 0.1 MPa. The consistency between the two sets of experimental data ( phase diagrams and VE) was analyzed from a theoretical perspective; we noticed that as the alkyl chain length, n, of the linear alcohol varies both the pressure dependence of the phase diagrams and the critical excess molar volume change sign.