A process for preparing Trifluorbenzoesäuren

The present invention relates to a process for the preparation of the formula Trifluorbenzoesauren DOLLAR F1 wherein R is a straight-chain or branched alkyl radical having 1 to 6 carbon atoms, an unsubstituted phenyl, a substituted phenyl radical which contains one or two alkyl or alkoxy groups each having 1 to contains 4 carbon atoms, or an araliphatic radical having 7 to 12 carbon atoms by which R F2 · 1 · · and R 2 are a compound of the formula · DOLLAR same or different and are -CN, -COOR 3 · · where R · 3 · H, Li, Na, K, MgCl, MgBr, MgI, · · 1 / 2Mg, 1 · · / 2Ca or an alkyl group having 1 to 6 C atoms, or -CONR 4 · · R * 5 *, wherein R * 4 * and R * 5 * are the same or different and are an alkyl radical having 1 to 6 carbon atoms, radicals, with at least one organometallic compound of the formula CuR, CuLiR¶2¶, MgXR, ZnR ¶2¶, LiR, AlX¶2¶R, AlXR¶2¶, AlR¶3¶ or Al¶2¶Cl¶3¶R¶3¶, wherein R in the formula (1) has the meaning given and X is Cl . Br or I, C in the presence of an inert solvent at -80 to +150 DEG, treated at 0 to 250 DEG C, the reaction product in the presence of water in the absence or presence of an acid, and the resulting trifluoroisophthalic acid of the formula DOLLAR F3 at 80 decarboxylated to 280 ° C.