B-27 Liquid-liquid equilibria of binary mixtures {xylene + ionic liquid}: Experimental data and thermodynamic modeling using a group contribution equation of state

E. GONZALEZ; E. MACEDO; A. DOMINGUEZ; S. B. BOTTINI; S. PEREDA

Conferencia; 3rd Asian-Pacific Conference on Ionic Liquids and Green Processes, Beijing; 2012

Ionic liquids (ILs) represent an unusual class of solvents with many novel and promising properties. Detailed knowledge of their phase behavior is required to find new applications and/or to design new technological processes. Furthermore, considering the large number of ILs that can be syntetized, methods to predict their phase behavior are needed. In this work, experimental liquid-liquid equilibrium (LLE) data for binary mixtures {o-xylene,or m-xylene, or p-xylene (1) + ionic liquid (2)} were measured at T = 298.15 K and atmospheric pressure. The ILs studied in this work were 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [Emim][NTf2], and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [Hmim][NTf2]. The experimental results show that the alkyl chain length of the cation has an important effect on the solubility of aromatic hydrocarbons in ionic liquids. Moreover, the solubility of xylene isomers in ILs depends on the position of the second methyl group. In general, o-xylene shows higher solubilitity in the studied ILs. Furthermore, the group contribution equation of state[1,2] (GC-EOS) was applied to model the phase behavior of binary systems of xylenes mixed with ILs of the homologous family 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [x-mim][NTf2]. New pure group parameters for the ionic liquid functional group [-mim][NTf2] and interaction parameters between this group and the paraffin (CH3, CH2) and aromatic (ACH, ACH3) groups were obtained. The GC-EOS extended with the new parameters was applied to predict LLE and VLE of binary mixtures {benzene, or xylene + x-mimNTf2}. The results show that the GC-EOS is capable of predicting the phase behavior of this kind of mixtures.