PURPOSE: To produce an organic fluorine compound from the corresponding aromatic halide having trifluoromethyl group by halogen-exchange reaction at a specific temperature, by using benzonitrile as the reaction solvent.
CONSTITUTION: The objective compound of formula II (V is N, CH, C-W, C-CF3, or C-F; W is Cl, Br, CN or NO2; p is integer of 0W4; q is integer of 1W4; l+p+q is integer of ≤5) useful as an intermediate of pharmaceuticals and agricultural chemicals, etc., can be prepared by reacting the compoun of formula I (X is H, CH, C-Y, C-CF3 or C-Z; Y is Cl or Br; Z is F, CN or NO2; l and m are integer of 1W4; n is integer of 0W3; l+m+n is integer of ≤5) with a fluorination agent in benzonitrile at 190W400°C under at least the autogeneous pressure in the presence or absence of a phase-tranfer catalyst. The side-reaction and the formation of carbonized product can be suppressed by the use of the above solvent having high thermal stability. Furthermore, the temperature control of the reaction system can be facilitated, and the objective compound can be produced in high yield, economically on an industrial scale.
HIROTA KOITSU
NAKAMURA TOMOAKI
