Sublimation pressures of tetraphenylmethane and associated bond energies

Abstract

The sublimation pressures of tetraphenylmethane in the temperature range 396 to 466 K have been determined from the simultaneous measurements of the torsional recoil and the rate of mass effusion. The enthalpy and entropy of sublimation derived from the least-squares analyses of the results are (33.65 ± 0.60)kcal thmol −1 and (56 ± 2)cal thK −1mol −1 respectively. The average bond dissociation energy 〈 D〉(CPh) is calculated to be (99.2 ± 1.5)kcal thmol −1. Estimates of the bond dissociation energies for the stepwise dissociation processes of CPh 4 are presented.