The Enthalpy of Formation and C−H Bond Enthalpy of Hydrofullerene C60H36

Abstract

The standard molar enthalpy of combustion of hydrofullerene C60H36 was determined by static bomb calorimetry, ΔcH°m = −(29769 ± 25) kJ·mol-1. Using this result and the standard molar enthalpy of sublimation, ΔsubH°m = (175 ± 5) kJ·mol-1, the values of the standard molar enthalpies of formation of C60H36 in the crystalline and gaseous states were calculated: ΔfH°m(C60H36, cr) = (1013 ± 26) kJ·mol-1 and ΔfH°m(C60H36, g) = (1188 ± 26) kJ·mol-1. The enthalpy of reaction C60H36(g) = C60(g) + 36 H(g) was found to be (9196 ± 30) kJ·mol-1, or (255.4 ± 0.8) kJ·mol-1 per one C−H bond. The enthalpy of reaction C60F36(g) + 36 H(g) = C60H36(g) + 36 F(g) was calculated, ΔrH°m = (1421 ± 203) kJ·mol-1, or (39.5 ± 5.6) kJ·mol-1 per one H atom. The enthalpies of bond breaking and of F to H replacement were compared with the analogous values in some other organic compounds.