Determination of the Krichevskii function in near-critical dilute solutions of I2(s) and CHI3(s)

In the present work the solubility of CHI3(s) in xenon has been spectrophotometrically measured at different sub- and supercritical temperatures, and along the isotherm of T = 316.9 K at pressures between 5 MPa and 10 MPa. Using these results together with already available solubilities for I-2(s) and CHI3(s) in near-critical solvents, we have calculated the Krichevskii function (partial derivative p/partial derivative x)(V, T)(infinity) for a series of dilute near-critical binary solutions; this quantity accounts for solute-solvent interactions in the binary mixtures. The Krichevskii functions are found to be only weakly dependent on the temperature. The fluid density dependence of (partial derivative p/partial derivative x)(V, T) is discussed in terms of intermolecular interactions; the fluorinated solvents show very low interaction with the solutes. Krichevskii functions can be used to predict various thermodynamic properties of the solution, (C) 1998 Academic Press.