Method for producing 2,3,4,5-tetrafluorobenzoic acid

摘要

2,3,4,5-Tetrafluorobenzoic acid of the formula (1) …IMAGE… is prepared by heating N'-substituted N-aminotetrafluorophthalimides of the formula (2) …IMAGE… in which X represents the radical …IMAGE… in which R1 and R2 represent a hydrogen atom, an alkyl(C1-C10) group, aryl group, alkyl(C1-C6)-CO group or aryl-CO group, is being possible for the aryl groups, or aryl-CO groups, in the case of R1 and R2 to be substituted on the aromatic ring by fluorine and/or chlorine atoms and/or alkyl(C1-C4) groups, or R1 and R2 together represent a phthaloyl radical which can be substituted on the aromatic ring by 4 chlorine atoms or 4 fluorine atoms, or in which X represents the radical which can be substituted on the aromatic ring by fluorine and/or chlorine atoms and/or alkyl(C1-C4) groups,… in aqueous medium at a pH from approximately -1 to approximately +1 at temperatures of approximately 160 to 220 DEG C.