Patent ID: 7365229

Claim:
A process for preparing peroxidic perfluoropolyethers of formula: X 1 —O(CF 2 O) n1 (CF 2 CF 2 O) m1 (CF 2 (CF 2 ) z CF 2 O) p1 (O) h —X 2 (I) wherein: X 1 and X 2 , equal to or different from each other, are chain end groups selected between —CF 2 COF and —COF; n1, m1, p1 and h are integers such that the number average molecular weight is in the range 700-100,000; z=1 or 2; with the proviso that: the m1/n1 ratio is between 0.2 and 10; the p1/(n1+m1) ratio is lower than 0.05; the h/(n1+m1+p1) ratio is such that the PO content, defined as grams of active oxygen/100 g of compound, is in the range 0.8-4.5; the perfluorooxyalkylene units being statistically distributed along the polymeric chain; said process carried out by photooxidation, in the presence of CF 2 ═CFCOF (perfluoroacryloyl fluoride, PFAF), of tetrafluoroethylene (TFE) in the presence of UV light having wave length between 200 and 350 nm, at a temperature in the range from −30° C. to −100° C., by using solvents, liquid under the reaction conditions, selected from perfluorocarbons and (mono)hydrofluorocarbons, having the following general formula: C y F (2y+2−x) H x (II) wherein y is an integer from 2 to 4; x is an integer equal to 0 or 1; or related mixtures.