Ionic liquids excess volume, solutions

Zafarani-Moattar, M.T. and Shekaari, H. Volumetric and speed of sound of ionic liquid, l-butyl-3-methylimidazolium hexafluorophosphate with acetonitrile and methanol at T = (298.15 to 318.15) K, /. Chem., Eng. Data, 50,1694,2005. Wang, J. et al.. Excess molar volumes and excess logarithm viscosities for binary mixtures of the ionic liquid l-butyl-3-methylimidazolium hexafluorophosphate with some organic solvents, /. Solution Chem., 34, 585, 2005. 

Heintz, A. et al.. Excess molar volumes and liquid-liquid equilibria of the ionic liquid l-methyl-3-octyl-imidazolium tetrafluoroborate mixed with butan-l-ol and pentan-l-ol, /. Solution Chem., 34,1135, 2005. 

Bhujrajh P, Deenadayalu N. Liquid densities and excess molar volumes for binary systems (ionic liquids plus methanol or water) at 298.15, 303.15 and 313.15K, and at atmospheric pressure. J. Solut. Chem. 2007. 36, 631-642. 

Heintz A, Klasen D, Lehmann J K. Excess molar volumes and viscosities of binary mixtures of methanol and the ionic liquid 4-methyl-N-butylpyridinium tetrafluoroborate at 25, 40, and 50 °C. J. Solution Chem. 2002. 31, 467-476. 

One important solute is water, which is completely miscible in imidazolium salts with short alkyl side chains and hydrophilic anions such as d, but is only partially miscible with ionic liquids with longer side chains and less hydrophilic anions. Extraction into an aqueous phase is important for product recovery from an ionic liquid medium. Hanke and Lynden-BeU [143] used simulation to investigate thermodynamic properties and local structure in mixtures of water with [MMIM]Q and [MMIM][PF6] liquids. They found that the excess energy of solvation was negative for the chloride and positive for the [PF ]" liquid, as shown in Fig. 4.2-12. There is a similar difference in the molar volumes of mixing shown in Fig. 4.2-13. This is consistent with the perception of the [PFe]" anion as being more hydrophobic than the chloride anion. 

Figure 5.10 Excess volumes, V, of H20-[CgCjim]Cl system as a function of mole fraction of ionic liquid, [CgC imJCl, and temperature (the order of markers, for instance, at Xu =0.4 indicates temperatures from 283 K ( ) to 313 K (+)). Vials in the inset numbered from 26 to 30 correspond to a concentration of Xjl=0.15, 0.21,0.24,0.29, and 0.41, respectively.Those upside down indicate gel-like solutions.

Where SP is a solvation p>arameter related with the free energy change such as gas-liquid partition coefficient, specific retention volume or adjusted retention time at a given temperature. The capital letters represent the solutes properties and the lower case letters the complementary properties of the ionic liquids. The solute descriptors are the excess molar refraction E, dipolarity/ polarizability S, hydrogen bond acidity basicity, A and B, respectively, and the gas-liquid partition coefficient on n-hexadecane at 298 K, L. The solute... 

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