| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing highly pure 2,6- naphthalenedicarboxylic hardly containing a ring-brominated naphthalenedicarboxylic acid which is an impurity, without using an expensive solvent and without requiring equipment corresponding to a high temperature and high pressure condition. SOLUTION: An aqueous solution of a crude dialkali salt of 2,6- naphthalenedicarboxylic acid is subjected to a reduction treatment in the presence of zinc, and the treated aqueous solution is acidified to precipitate a highly pure crystal. Further, when the aqueous solution of the dialkali salt of the 2,6-naphthalenedicarboxylic acid after the reduction treatment is treated with an absorbent, the purer crystal can be obtained. The crude dialkali salt of the 2,6-naphthalenedicarboxylic acid is preferably the one obtained by adding the crude 2,6-naphthalenedicarboxylic acid to an aqueous solution obtained by dissolving one or more selected from a group of sodium hydroxide, sodium carbonate, potassium hydroxide, potassium carbonate and ammonia in an amount of the neutralizing equivalent or more.
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