In this work, ionic liquids are evaluated for the first time as solvents for
extraction and entrainers in separation processes involving terpenes and terpenoids. For
that purpose, activity coefficients at infinite dilution, γ13
∞, of terpenes and terpenoids, in
the ionic liquids [C4mim]Cl, [C4mim][CH3SO3], [C4mim][(CH3)2PO4] and
[C4mim][CF3SO3] were determined by gas−liquid chromatography at six temperatures
in the range 398.15 to 448.15 K. On the basis of the experimental values, a correlation
of γ13
∞ with an increase of the solubility parameters is proposed. The infinite dilution
thermodynamic functions were calculated showing the entropic effect is dominant over
the enthalpic. Gas−liquid partition coefficients give indications about the recovery and
purification of terpenes and terpenoids from ionic liquid solutions. Presenting a strong
innovative character, COSMO-RS was evaluated for the description of the selectivities
and capacities, showing to be a useful tool for the screening of ionic liquids in order to
find suitable candidates for terpenes and terpenoids extraction, and separation.
COSMO-RS predictions show that in order to achieve the maximum separation
efficiency, polar anions should be used such as bis(2,4,4-trimethylpentyl)phosphinate or acetate, whereas high capacities require
nonpolar cations such as phosphonium.
