No abstract

Retention factors of eleven heavy n-alkanes (C21H44, C22H46, C23H48, C24H50, C25H52, C27H56, C28H58, C31H64, C34H70, C36H74, and C40H82) and C60 and C70 fullerenes were measured within 311−431 K and 8.7−39 MPa by supercritical fluid chromatography in an open tubular capillary column. This data set was obtained using a poly(methyl-n-octyl siloxane) stationary polymer and carbon dioxide as the mobile-phase fluid. The retention factors are employed to derive the partial molar volumes of the solutes at infinite dilution in CO2 and the infinite-dilution molar enthalpies of transfer of the solutes from the stationary phase to supercritical CO2. The partial molar volumes are subsequently transformed to quantities characterizing short-range solute−CO2 interactions, and the effects are shown of the corrections for dissolution of CO2 in the stationary polymer on these quantities. Distinct differences between the n-alkane−CO2 and the fullerene−CO2 interactions have been found and discussed. Overall, the resultant partial molar properties suggest that the fullerene−CO2 interactions are less attractive than the n-alkane−CO2 interactions.