Tetrafluoroethylene telomerization using dibromohaloethanes as telogens

Carrier mediated telomerization (CMT) between C2F4 and bromochlorofluoroethanes has been evaluated in terms of product distributions arising from CMT and ‘normal’ telomerization. The effect of parameters like type of initiator and telogen, TFE pressure and temperature on the reaction has been studied. The peroxide initiated telomerization between dibromohaloethanes and C2F4 offers an easy synthetic route to α,ω-dibromo perfluoroalkanes Br(CF2)nBr with n = 2, 4, 6 and 8. The selectivity of the CMT products versus those from “normal” telomerization depends mainly on the choice of telogen and on its ability to act as ‘bromine donor’ in the radical telomerization. These perfluoroalkyl dibromides are useful intermediates for other derivatives, for example, perfluorinated mono- and diolefins, Br(CF2)nCHCH2 and CH2CH(CF2)nCHCH2.

‘Carrier mediated telomerization’ (CMT) between 1,2-dibromo-1,2-dichloro-1,2-difluoroethane, BrCFClCFClBr and C2F4 (TFE) is a new route to α,ω-dibromo perfluoroalkanes Br(CF2)nBr with n = 2, 4 and 6. Figure optionsDownload as PowerPoint slide