Free radical addition to olefins. Part 11.—Telomerization of tetrafluoroethylene with dibromodifluoromethane and trifluoroiodomethane

Abstract

The telomerization of tetrafluoroethylene in the gas phase by CF₂Br₂ results in the formation of products of general formula Br[CF₂]_nBr n= 2–11. When CF₃I was used the products were found to be CF₃[CF₂CF₂]_nI where n= 1 to 5. Transfer constants have been determined for radicals containing various numbers of tetrafluoroethylene units, and Arrhenius parameters from temperature variation data. Trends in the transfer constants are compared with previous work in solution. The activation energies from the transfer constants are combined with known values of the activation energies of the addition steps to give estimates of the activation energies of the halogen abstraction steps.