Thermochemistry of Fullerene C60 Solutions in Toluene, o-Xylene and o-Dichlorobenzene

In hermetic highly sensitive calorimeter with an isothermal shell, the enthalpies of dissolution of fullerene C60 in toluene, o-xylene and o-dichlorobenzene were measured at temperatures of 288.15 K and 308.15 K at various concentrations of the dissolved substance. On the basis of the measured values and literature data, standard thermodynamic functions of the dissolution of C60 in the above mentioned solvents have been found at the indicated temperatures. The fact of the change in the sign of the dissolution enthalpy for all three systems under study at a transition to a temperature of 308.15 K has been revealed. A negative value of the dissolution entropy indicates the presence of a constant interaction in these liquid systems, which decreases sharply at 308.15 K.

DEPENDENCE OF DISSOLUTION ENTHALPY OF POLYVINYLPYRROLIDONE IN WATER ON ITS INITIAL MOISTURE CONTENT

Changes in integral and differential enthalpies of dissolution of polyvinylpyrrolidone (PVP) of different molecular weight in water were determined as a function of initial moisture content of the polymer. Hydration numbers were calculated.