| abstract |
A process for the manufacture of benzoic acid is described. The process is based on the reaction of toluene in a liquid phase oxidation with an oxygen containing gas in the presence of a phase-transfer catalyst (a), a transitionn metal salt (b) and traces of a polar solvent, such as water, the molar ratio between (a) and (b) being in the range of between 0.25:1 to 1.5:1. The phase-transfer catalyst is selected from quaternary ammonium and phosphonium salts having a total carbon atoms in the range of 17 to 58, the anion bound thereto being selected from Br⁻, F⁻, Cl⁻, OH⁻, CH₃COO⁻ or HSO₄⁻. The benzoic acid produced is characterized by its very high purity and high conversion reaching generally values of above 95%. |