Patent ID: 7148384

Claim:
A process for preparing compounds of the formula (I) in which R 1 is C 1 –C 12 -perfluoroalkyl or C 1 –C 12 -perfluoroalkoxy R 2 is hydrogen, fluorine, chlorine, bromine, C 1 –C 4 -alkyl, C 1 –C 4 -alkoxy, nitro, cyano or COOR 4 where R 4 is hydrogen or C 1 –C 4 -alkyl and R 3 is hydrogen, fluorine or chlorine, or two of the R 1 , R 2 and R 3 radicals together are difluoromethylenedioxy, tetrafluoroethylene-1,2-dioxy, 2-oxytetrafluoroethyl or (oxydifluoromethoxy)difluoromethyl, comprising combining compounds of the formula (IIa) or (IIb) in which R 1 , R 2 and R 3 are each as defined above and Z 1 is isopropyl, propenyl, 2-hydroxy-2-propyl, 2-hydroperoxy-2-propyl or 1-methyloxiranyl and Z 2 is O,O-bis(2-oxydiisopropyl) with 0.1 to 30 mol % of an N-hydroxyphthalimide to form a mixture; degassing the mixture; and adding an oxidizing agent.