Synthesis of fluorinated telomers. Part 6. Telomerization of hexafluoropropene with alpha,omega-diiodoperfluoroalkanes

The synthesis of highly fluorinated telomers produced from the thermal bulk telomerization of hexafluoropropene (HFP) with alpha,omega-diiodoperfluoro alkanes is described. That involving 1,2-diiodotetrafluoroethane was unsucc essful because of the thermal decomposition of this diiodide from 190 degre es C. An optimization of the telomerization reaction involving 1,4-diiodope rfluorobutane taking into account key parameters such as the initial [IC4F8 I](0)/[HFP](0) molar ratio, the temperature and the time of the reaction is attempted. The conditions for the highest conversion of IC4F8I and also fo r directing the reaction toward the monoadduct or the diadduct are discusse d. Both these telomers were reduced with tributylstannane into HC4F8(C3F6)( x)H (with x=1 or 2) and H-C3F6-C4F8-C3F6-H, the H-1 and F-19-NMR spectra of which confirmed the structure of each derivative. (C) 1999 Elsevier Scienc e S.A. All rights reserved.