The liquid-liquid solubility phase diagram of squalane (B) plus dibutyl-o-phthalate (C) has been measured, the consolute temperature of which was found to be 302.20K. This liquid-liquid coexistence curve was applied to calculate the interaction parameters Abc at various temperatures on the basis of the Hildebrand-Scatchard-Flory-Huggins binary system formula, together with the phase equilibrium condition (method I) or the critical point conditions (method II). It is shown that the value of Abc at critical temperature obtained by the one is consistent with the other. The infinite dilution activity coefficients at 313.15K were measured by gas-liquid chromatography for some aliphatic, alicyclic of C6 and C7 hydrocarbons in the mixtures of squalane (B) plus dibutyl-o-phthalate (C) over the entire composition range. The values of Abc calculated from the Hildebrand-Scatchard-Flory-Huggins ternary system formula have been reported. It can be shown that the values of Abc by different probe solutes are nearly a constant, the average value of which is consistent with the value by the coexistence curve reasonably. That is , the testing of thermodynamics consistency for our results is satisfied.

Key words: SOLVENTS, THERMODYNAMIC PROPERTIES, SOLUBILITY, GAS LIQUID CHROMATOGRAPHY, SPINACANE, INTERACTIONS, DIBUTYL PHTHALATE