Free radical addition to olefins. Part XIII. Photolysis of bromodichloromethane in the presence of olefins

Abstract

Photolysis of bromodichloromethane alone and in the presence of ethylene and vinyl fluoride has been investigated. Although the principal photolytic step involves carbon–bromine bond fission: CHCl₂Br [graphic omitted] CHCl₂·+ Br· subsequent chain carrying processes involve hydrogen abstraction as much as bromine abstraction: R·+ CHCl₂Br → RH + CCl₂Br·, R·+ CHCl₂Br → RBr + CHCl₂· The almost equal importance of hydrogen and bromine abstraction from bromodichloromethane leads to a mixture of products in which both dichloromethyl (CHCl₂·) and bromodichloromethyl (CBrCl₂·) radicals are chain carrying species. In contrast to earlier reports of liquid phase studies the radical which predominates in addition to alkenes in the gas phase is the bromodichloromethyl radical.