PRODUCTION OF PERFLUOROALKYL IODIDE

PROBLEM TO BE SOLVED: To obtain a perfluoroalkyl iodide with low chain length distribution, useful as e.g. a raw material for fluorosilicones in high selectivity and yield by reaction of a specific telogen with tetrafluoroethylene under specified conditions. SOLUTION: A reaction vessel equipped with a distillation column is charged with a telogen of formula I ((n) is 2-12) such as perfluoroethyl iodide or perfluoroisopropyl iodide and tetrafluoroethylene in the molar ratio: the latter to former of (m) followed by refluxing the telogen in the presence of a free radical initiator such as a ketone peroxy compound (the amount to be used is pref. 0.002-0.2mol per mol of the tetrafluoroethylene) at a temperature lower than the boiling point of the perfluoroalkyl iodide under the pressure inside the distillation column to carry out a telomerization, thus obtaining the objective perfluoroalkyl iodide of formula II ((m) is 1-6). The reaction is preferably conducted while continuously feeding the distillation column with the tetrafluoroethylene.