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    • 48. 发明专利
    • PURIFICATION OF NAPHTHALENECARBOXYLIC ACID
    • JPH02250849A
    • 1990-10-08
    • JP7126789
    • 1989-03-23
    • SUMIKIN CHEMICAL
    • YAMADA TERUAKIMAEDA KAZUHIKOSUGIURA KAZUKINAMEKATA TAKESHI
    • C07C51/487C07C63/34
    • PURPOSE:To obtain a purified naphthalenecarboxylic acid free from discoloration in high purity by a simple operation by oxidizing a substituted naphthalene to give a crude naphthalenecarboxylic acid and additionally oxidizing the crude naphthalenecarboxylic acid with O2 in the presence of an alkali metal compound in a solvent. CONSTITUTION:A substituted naphthalene is oxidized to give a crude naphthalenecarboxylic acid(NCA), which is oxidized with molecular oxygen in the presence of an alkali metal compound in a solvent, preferably dissolved in an alkali aqueous solution, almost all oxidation intermediates of impurities are converted into carboxylic acids to give a purified naphthalenecarboxylic acid. Further the amount of colored components is reduced and hue is extremely improved by the oxidation treatment. The oxidation treatment is used together with decoloring treatment with a solid adsorbent to provide a high-quality product. Further, after the oxidation of the NCA with O2, a NCA alkali salt is precipitated by introducing CO2 or SO3 into the aqueous solution or the NCA alkali salt is precipitated by cooling or concentration to give NCA having more excellent purity and hue.