Thermal decomposition of tert-butyl 1-arylcycloalkanepercarboxylates

A series of tert-butyl 1-arylcycloalkyl peresters was prepared, and the rate constants for the peresters' thermal decomposition were measured at several temperatures. The decomposition rates and aryl-substituent effects on the decomposition rates for the three series of peresters are remarkably similar to each other and to the acyclic alpha,alpha-dimethylbenzyl analogue previously investigated. The magnitude of the activation parameters for the rates of thermolysis of the alicyclic peresters and the solvent viscosity effects on these rates suggest that the 1-arylcyclobutyl (2), -cyclopentyl (3), and -cyclohexyl (4) peresters undergo thermal decomposition primarily by the concerted, two-bond-cleavage mechanism and that the 1-arylcyclopropyl peresters (1) undergo thermolysis primarily by the stepwise mechanism.