Journal of Chemical and Engineering Data, Vol.57, No.4, 1064-1071, 2012
Solute Partitioning Between 1-n-Butyl-3-methylimidazolium Trifluoromethanesulfonate Ionic Liquid and Supercritical CO2
Limiting partition coefficients (K-factors) of a selection of low-to-medium volatility solutes in biphasic 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim][TfO]) ionic liquid-supercritical carbon dioxide (IL-scCO(2)) system were obtained by capillary column supercritical fluid chromatography (SFC) with [bmim][TfO] as the stationary liquid and scCO(2) as the carrier fluid. Solute selection included 24 compounds of diverse volatilities and chemical functionalities and the retention factors were measured within (313.2 to 353.2) K and (7.3 to 23.2) MPa. At a constant temperature, some pressure-tunable selectivity can be obtained through changes in the operating pressure and the scCO(2) density. At a fixed temperature and density of CO2, solute partition coefficients were correlated in terms of Abraham's linear solvation energy relationships. Compared to our previous studies with other ILs ([hmim][Tf2N], [bmim][MeSO4], and [thtdp][Cl]), the loss of [bmim][TfO] from the column during the experimental run was markedly lower in the present work.