Some enthalpies of solution of C{sub 60} and C{sub 70}. Thermodynamics of the temperature dependence of fullerene solubility
- Drexel Univ., Philadelphia, PA (United States)
- Moscow State Univ. (Russian Federation)
The enthalpy of solution of C{sub 60} in toluene, carbon disulfide, decalin, and N,N-diethylaniline and of C{sub 70} in CS{sub 2} has been measured using an isoperibol solution calorimeter. Exothermic heats of solution are observed in all cases. The heat of solution of C{sub 60} in toluene is -8.6{+-}0.7 kJ mol{sup -1}; in carbon disulfide it is -20{+-}1 kJ mol{sup -1}. In decalin, slow dissolution prevents an accurate determination, but the heat of solution is less than -5 kJ mol{sup -1}. In N,N-diethylaniline, a fast exothermic step comparable to that observed in other systems is followed by a much larger heat evolution, implying that a chemical reaction is occurring. The heat of solution of C{sub 70} in Cs{sub 2} is -9{+-}1 kJ mol{sup -1}. A thermodynamic theory of the temperature dependence of fullerene solubility is presented. The central idea is that the unusual temperature dependence of the solubilities of fullerenes is caused by the formation of solvated crystals. The calorimetric results suggest that the negative temperature dependence of the solubility of fullerenes may be quite general if the solid phase in equilibrium with the saturated solution is unsolvated fullerene. 24 refs., 6 figs., 2 tabs.
- OSTI ID:
- 263164
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 16 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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