PURPOSE: To obtain the title compound bearing perfluoroalkyl groups of different carbon atoms by reaction of di(perfluoroalkanoyl)peroxide with an aromatic or heteroaromatic compound in the presence of pyridinium salt.

CONSTITUTION: In presence of a pyridinium salt of formula I (R1, R2 are halogen, alkyl, cyano, methoxy; m is 1W10; l1, l2 are 0, 1), the reaction of di(perfluoroalkanoyl)peroxide of formula II (n is 1W10) with an aromatic compound or heterocyclic aromatic compound of formulas III, IV and V (R3 is halogen, alkyl, nitro, ester, alkoxy, hydroxyl: X is O, S; l3 is 0, 1; l4 is 0W3) is carried out to introduce F(CF2)n in formula 11 and/or F(CR2)m of formula I into the aromatic or heterocyclic aromatic ring in the compounds of formulas IIIWIV whereby the title compound is obtained. The products are useful as a synthetic intermediate of surfactant, medicines and agrochemicals.