PROCESS FOR PREPARING BENZENEDICARBOXYLIC ACID ISOMERS HAVING HIGH PURIFICATION DEGREE Russian patent published in 1995 - IPC

FIELD: manufacture of films and fibres. SUBSTANCE: the product: a benzenedicarboxylic acid isomer. The color index is 7 deg. The content of KBA is 14 mln. Reagent 1: n-xylene. Reagent 2: air. Process conditions: in the presence of a Co-Mn catalyst comprising Ni, Cr, Zr, Ce or mixtures thereof and a halide compound. In this case after the first the solvent and then treated with a recycling solvent. The resulting slurry is thereafter heated to high temperature to extract the impurities contained in a solid product, cooled and treated with air and catalysts at the second oxidation stage. The precipitate formed at the second oxidation stage is once again separated from the solvent and once again treated with a recycling solvent. The slurry is then heated to high temperature to be extracted, cooled and treated with air and catalysts at the third oxidation stage. EFFECT: more efficient preparation process. 7 cl, 1 dwg, 2 tbl