Phase equilibrium investigation with ionic liquids and selectivity in separation of 2-phenylethanol from water

• The LLE binary and ternary phase diagrams with ionic liquids.
• Separation of 2-phenylethanol from water with bis{(trifluoromethyl)sulfonyl}imide-based ILs.
• The selectivity of extraction is in order: [S221][NTf2].
• [HMMOR][NTf2] < [AMIM][NTf2].

This work presents some important issues and topics related to possible extraction of 2-phenylethanol (PEA) from aqueous phase “in situ” during the biosynthesis with ionic liquids (ILs). It consists of a series of experimental phase equilibrium measurements in binary and ternary systems. Three ILs as extraction media are proposed for the extraction process based on phase equilibria in ternary systems {IL (1) + PEA (2) + water (3)} at temperature T = 308.15 K and ambient pressure. The systems are composed of the following ILs: 1-hexyl-1-methylmorpholinium bis{(trifluoromethyl)sulfonyl}imide, [HMMOR][NTf2], 1-allyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [AMIM][NTf2], and diethylmethylsulfonium bis{(trifluoromethyl)sulfonyl}imide, [S221][NTf2]. A differential scanning calorimetry (DSC) was used to determine the thermal properties of the ILs. The synthesis of new [HMMOR][NTf2] IL and its thermal and physicochemical properties as density, viscosity, surface tension were presented. The volume expansivity, as well as the surface thermodynamic functions, such as surface entropy and enthalpy have been derived from the temperature dependence of the surface tension values, as well as the critical temperature, parachor and speed of sound for all ILs were presented. The correlation of the liquidus curves in binary systems and tie-lines in ternary systems was undertaken with the NRTL equation. These results of solubility can be used to design future alternative technological processes of the extraction of PEA from fermentation broth.

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