| 摘要 |
PURPOSE:To enable the purification of the titled compound, by dissolving crude 2,6-naphthalenedicarboxylic acid in an aqueous solution of NaOH, K2CO3, etc., adding a water-soluble salt or hydroxide of the same cation and precipitating the objective compound as di-Na salt or di-K salt. CONSTITUTION:Crude 2,6-naphthalenedicarboxylic acid produced by the oxidization of 2,6-dialkylnaphthalene is dissolved in an aqueous solution of NaOH, KOH, Na2CO3 or K2CO3 of >=11 pH. A water-soluble salt or hydroxide of the cation same as the ion used above is added to the solution to precipitate the objective compound in the form of di-Na salt of di-K salt. The amount of the water-soluble salt or hydroxide of the above common cation is <=5mol/l as a cation concentration and below the solubility of the added component. preferably, the solution is added with 1-3wt% NaCl before or after salting-out teatment and is subjected to activated carbon treatment. EFFECT:A colorless objective compound having a purity of >=99.8% can be produced by combining the above process with activated carbon treatment.
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