| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for industrially producing at low cost in simple processes a high-purity aromatic polycarboxylic acid good in hue and favorable in particle size, such as 2,6-naphthalenedicarboxylic acid or 4,4'- biphenyldicarboxylic acid from the crude corresponding aromatic polycarboxylic acid. SOLUTION: This method for producing a high-purity aromatic polycarboxylic acid comprises the following steps: (I) formation an aromatic polycarboxylic acid amine salt from at least one amine to be a aliphatic amine and/or alicyclic amine such as triethylamine or trimethylamine and the crude corresponding aromatic polycarboxylic acid, (II) a continuous salt decomposing process which comprises (1) continuously feeding a salt tank with the aromatic polycarboxylic acid amine salt decomposing aqueous solution, (2) distilling off the amine(s) and water by heating, and (3) feeding out a slurry containing the aromatic polycarboxylic acid from the tank, and (III) the separation and collection process of the aromatic polycarboxylic acid crystal from the slurry where the mother liquor is circulated to the salt decomposing process.
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