DETERMINATION OF ENTHALPIES OF FORMATION OF ORGANIC FREE-RADICALS FROM BOND-DISSOCIATION ENERGIES - 1 - HYDROCARBON RADICALS

The enthalpies of formation (Delta Hf degrees) for 24 hydrocarbon radi cals (R-.), mainly polycyclic aromatic radicals with the complex struc ture, were determined from the published data on bond dissociation ene rgies. The Delta Hf degrees values of the corresponding molecules were calculated, in the majority of cases, by the macroincrement method. C alculations by the group contribution method were performed. Some Delt a H(f)degrees(R-.) values were compared to those calculated by the add itive-group method. Calculations were performed, and the conjugation e nergies of the radicals were discussed. The errors of determination of the Delta H(f)degrees(R-.) values found were estimated. Due to this w ork, the database for Delta H(f)degrees values of hydrocarbon radicals was increased more than by 25%.