Abstract:

A micro-oxygen-bomb calorimeter with a bomb of 4.8 cm3 internal volume was constructed in our laboratory. About 10 mg of sample was needed for each combustion experiment. The energy equivalent of this calorimeter was determined with electric energy. The standard diviation of mean from 5 measurements was 0.02 %.The enthalpies of combustion of pure C60 and C70 were determined, △cUm0(C60,cr)=-(25947.1±8.5)kJ•mol-1, △cUm0(C70,cr)=-(29956.1±8.9)kJ•mol. The enthalpies of formation of the two compounds were derived. Using the Laidler-type bond parameters for aromatic hydrocarbons, the estimated strain energies in C60 and C70 molecules were close each other and close to the estimated value from the model compound, corannulene.

Key words: C₆₀, C₇₀, Micro-oxygeng-bomb calorimeter, Combustion enthalpy, Strain energy