Method for purifying 2,6-naphthalenedicarboxylic acid

摘要: A method for purifying a crude 2,6-naphthalenedicarboxylic acid obtained by the oxidation of 2,6-dialkylnaphthalene, which comprises A. PREPARING AN AQUEOUS SOLUTION OF DIALKALI SALT SAID CRUDE 2,6-NAPHTHALENEDICARBOXYLIC ACID, B. PRECIPITATING 40 TO 97 MOL PERCENT THE 2,6NAPHTHALENEDICARBOXYLATE DISSOLVED IN SUBSTANTIALLY AS MONOALKALI 2,6NAPHTHALENEDICARBOXYLIC ACID WHILE MAINTAINING PH said aqueous solution at value not lower than 6.3, and separating precipitate, C. CONVERTING SEPARATED PRECIPITATE ACID. If desired, prepared in step (a) may be treated with an adsorbent prior to being subjected (b). This treatment results removal most coloring impurities contained starting material.