Abstract The thermal decomposition of some highly branched perfluoroalkanes in the presence of molecular halogens (Cl 2, Br 2, I 2) has been studied. The clear-cut cleavage of the most hindered carbon-carbon bond and the trapping by halogens of the intermediate radicals so formed account for the product distribution. Kinetic measurements support a mechanism based on homolytic rupture of the perfluoroalkanes as the rate-determining ...