To produce a high-purity naphthalenedicarboxylic acid, good in hue and useful as a raw material for a polyethylene naphthalate(PEN) resin having excellent performances.
A crude naphthalenedicarboxylic acid obtained by carrying out the oxidizing reaction of a dialkylnaphthalene (e.g. dimethylnaphthalene) is dissolved in an aqueous solution containing aliphatic amines (e.g. triethylamine), and heavy metallic components contained as an impurity therein are removed so as to afford ≤100ppm amount thereof based on the naphthalenedicarboxylic acid by the filtration or treatment with a solid adsorbent. The resultant aqueous solution is then heated to conduct the hydrogenating treatment and the amines are distilled away to provide the objective high-purity naphthalenedicarboxylic acid.
SHIGEMATSU TAKASUKE
NAKAMURA KENICHI
TAKAGAWA MINORU
