Homolytic Decomposition oft-Alkyl 2,2-Dimethylperoxypropionates

Abstract Decomposition rates and products of t-alkyl 2,2-dimethylperoxypropionates were measured in cumene at several temperatures. The peroxyesters decomposed homolytically, depending on the structure of the t-alkyl moiety. The relative rates of the t-alkyl moieties to the 1,1-dimethylethyl one were: 1,1-dimethylbutyl (1.14), 1,1-dimethylpropyl (1.19), 1,1,2-trimethylpropyl (1.85), 1,1,3,3-tetramethylbutyl (2.10), and 1,1-dimethyl-2-phenylethyl (2.34). The decomposition showed an isokinetic relationship and the importance of stabilization by hyperconjugation. Based on these data, the decomposition mechanism, which contains a slight stretching of the Cα–Cβ bond to the peroxyl oxygen at the transition state is, discussed.