Patent ID: 7329784

Claim:
A process for preparing peroxidic perfluoropolyethers having a peroxidic content (PO) higher than 1.2 of formula: A-CF 2 O(CF 2 CF 2 O) m (CF 2 O) n —(CF 2 CF 2 OO) ml (CF 2 OO) nl CF 2 —B (I) wherein A, B, equal to or different from each other are Cl—, F—, ClCF 2 —, —COF, —OCOF, —CF 3 , m, ml, n, nl are integers such that the (m+ml)/−(n+nl) ratio is between 0.9 and 5 when (n+nl) is different from 0 and the m/n ratio is between 0.8 and 3, when n is different from 0, the number average molecular weight is in the range 35,000-45,000, wherein: when m/n is between 0.8 and 1.2 (n being different from 0), the PO is between 1.2 and 1.8; when m/n is between 1.7 and 3.0 (n being different from 0), the PO is between 2.5 and 3.5; by tetrafluoroethylene (TFE) photooxidation in the presence of UV light, at a temperature from −80° C. to 40° C., in the presence of a mixture of solvents formed of HFC-227 (heptafluoropropane) and a solvent selected from HFC-125 (pentafluoroethane) and FC-218 (perfluoropropane), in a volumetric ratio (HFC 125 or FC 218)/HFC 227 between 90/10 and 10/90, in the presence of a chain transfer agent.