Thermodynamic properties of C60 fullerene solutions in individual and mixed organic solvents

The solubility of C60 fullerene in tetrachloromethane-toluene and tetrachloromethane-1,2-dichlorobenzene mixtures has been studied in a wide range of solvent compositions within 298.15-338.15 K temperature interval. The equation describing the C60 solubility depending on the temperature and solvent composition has been suggested and thermodynamic functions of C60 solution have been calculated. We were able to identify the solid solvates in C60-tetrachloromethane-toluene and C60-tetrachloromethane-1,2-dichlorobenzene systems. The temperatures and enthalpies of incongruent melting of the observed solid solvates have been determined using the differential scanning calorimetry (DSC). We also measured the thermodynamic functions of solution and solvation of C60 in the individual tetrachloromethane, toluene and 1,2-dichlorobenzene. It was shown that temperature dependence of the Gibbs free energy of C60 solvation in the individual solvents is controlled by the entropy term.