THERMAL-DECOMPOSITION OF TERT-BUTYL 1-ARYLCYCLOALKANEPERCARBOXYLATES

A series of tert-butyl 1-arylcycloalkyl peresters was prepared, and th e rate constants for the peresters' thermal decomposition were measure d at several temperatures. The decomposition rates and aryl-substituen t effects on the decomposition rates for the three series of peresters are remarkably similar to each other and to the acyclic alpha,alpha-d imethylbenzyl analogue previously investigated. The magnitude of the a ctivation parameters for the rates of thermolysis of the alicyclic per esters and the solvent viscosity effects on these rates suggest that t he 1-arylcyclobutyl (2), -cyclopentyl (3), and -cyclohexyl (4) pereste rs undergo thermal decomposition primarily by the concerted, two-bond- cleavage mechanism and that the 1-arylcyclopropyl peresters (1) underg o thermolysis primarily by the stepwise mechanism.