Phase Behaviour of Ionic Liquid Organic

The binary phase behaviour of ionic liquids with different organic solvents has been measured. These organics include alkanes, alkenes, alkynes, cyclic hydrocarbons,  

Finally, the choice of anion of the ionic liquid has a large impact on the UCST of the system. Organics are much more soluble in ionic liquids with the 

Common UCST behaviour has also been observed for mixtures consisting of two ionic liquids with the same anion and a different cation.Less common lower eritical solution temperature (LCST) behaviour has been observed for binary ionic liquid mixtures with benzene,chloroalkanes and polymers. Interestingly, the LCST behaviour of benzene with an imidazo-lium-based ionic liquid changed via hour-glass to UCST behaviour when the imidazolium alkyl chain length was increased.Moreover, imidazolium-based ionic liquids were found to form clathrate structures with benzene at low temperatures, whereas the solid-liquid equilibria (SLE) of other organics or water with ionic liquids are simple eutectic systems. 

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Most (ionic liquid + organic) show immiscibility in the liquid phase with an upper critical solution temperature (UCST) found at low mole fractions of the ionic liquid. Therefore, the phase behaviour of (ionic liquid + organic) is similar to that of (ionic liquid + water) (Figure 11.4). However, unlike the system with water, the UCST of (ionic liquid + organic) decreases with increasing alkyl chain length of the cation. 58,60,84,89 92... 

Corresponding-states correlations, which were used for describing the phase behaviour of (ionic liquid- -organics) systems,also suffer from the same problem that the critical parameters of ionic liquids are required yet unknown. 

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