Preparation of fluorinated acetophenones

1. 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.

2. The process according to claim 1 , wherein compounds of the formula (IIa) are used in which Z 1 is isopropyl and propenyl.

3. The process of claim 1 , wherein compounds of the formula (IIa) are used in which Z 1 is isopropyl.

4. The process according to claim 3 , wherein the compounds used are obtained by reacting compounds of the formula (III)

in which

R 1 , R 2 and R 3 are each as defined in claim 1 with propene or isopropyl chloride in the presence of hydrogen fluoride.

5. The process of claim 1 , wherein conversion of compounds of the formulae (IIa) and (IIb) to compounds of the formula (I) is also carried out in the presence of transition metals or transition metal compounds.

6. The process claim 1 , wherein the oxidizing agent used is an oxygen-containing gas.

7. The process claim 1 , whereing unconverted or partially converted reactants, are recycled back into the reaction.