O – O Bond Dissociation Energies in Propionyl and Butyryl Peroxides

The kinetics of the decomposition of gaseous propionyl and butyryl peroxides was studied in a flow system. It was found that both compounds decompose in a unimolecular manner. The rate constant for the decomposition of propionyl peroxide is given by the equation k=2.5·1014·exp(−30 000/RT),and that for butyryl peroxide by the equation k=1.9·1014·exp(−29 600/RT).It is concluded that D(C2H5·CO·O−O·CO·C2H5)≃D(C3H7·CO·O−O·CO·C3H7)≃30·kcal/mole.The fates of the ethyl and propyl radicals produced in the decomposition are discussed.