FIELD: chemistry.
SUBSTANCE: invention relates to a method of recovering an aromatic carboxylic acid and an oxidation catalyst from an output stream from a process of producing aromatic polycarboxylic acids via liquid-phase oxidation of the corresponding aromatic precursor, the method comprising: (a) blowing off at least a portion of the mother solution of the process of producing an aromatic polycarboxylic acid into a solvent extraction system to obtain a concentrate containing organic compounds along with a catalyst as a residual stream; (b) separating the residual stream into a dicarboxylic acid rich stream, a catalyst and tricarboxylic acid rich stream, and a monocarboxylic acid rich stream via simultaneous extraction of the residual stream with two liquid phases using water and an organic solvent, followed by filtering; (c) separating benzoic acid and para-toluic acid and/or one of the isomers thereof from the monocarboxylic acid rich stream, extracting benzoic acid, extracting para-toluic acid and/or one isomer thereof; (d) separating terephthalic acid and isophthalic acid from the dicarboxylic acid rich stream, extracting terephthalic acid, extracting isophthalic acid; (e) separating trimellitic acid from the catalyst and tricarboxylic acid rich stream and extracting trimellitic acid; (f) separating a cobalt salt and a manganese salt from the catalyst and tricarboxylic acid rich stream.
EFFECT: enabling recovery of valuable chemical substances from a purge stream.
12 cl, 1 dwg
