| abstract |
2,5-dibromoterephthalic acid, an intermediate used for flame retardant applications, is prepared from terephthalic acid, in a single step, by brominating terephthalic acid in chlorosulfonic acid or fluorosulfonic acid, containing sulfur trioxide and employing an iodine catalyst. The reaction is carried out under mild conditions. The products, 2,5-dibrometerephthalic acid, with lesser amounts of terephthalic acid, bromoterephthalic acid, tribromoterephthalic acid, and tetrabromoterephthalic acid, are recoverable either by filtration of the cooled bromination suspension or by distillation of the chlorosulfonic or fluorosulfonic acid solvent and the further hydrolysis of the brominated terephthalic acid product. |