Process for obtaining (per)fluoropolyethers substituted at one or at both end groups with a halogen atom

A process for obtaining (per) fluoropolyethers substituted at one or at both end groups with a halogen atom selected from bromine or iodine, having the formula:

• A—CF2—O—(CF2CF2O)p—(CF2O)q—CF2—B (III)
• wherein
• A=B=halogen;
• or A=halogen and B=COOH or F, and the halogen is I or Br;
• p and q are integers such as to give a number average molecular weight (MW) in the range 350-5000 and the ratio p/q=0.5-2.0;
• said process consisting of treating di- or poly-acylperoxides having an average equivalent weight in the range 350-5000, of formula:
• T—CF2—O—[(CF2CF2O)p—(CF2O)q—CF2—CO—O—O—CO—CF2—(OCF2)q—(OCF2CF2)p]y—OCF2—COOH (II)
• wherein:
• y is an integer in the range 1-5;
• p and q are integers such as to give the indicated EW of formula (II) and the ratio p/q=0.5-2.0;
• T=COOH or F with the proviso that when T=COOH y=1-5, and when T=F then y=1
• with a halogen selected from iodine or bromine, in a polyhalogenated organic solvent, at temperatures between 20° and 80° C.