摘要:
A method is provided for purifying a crude N-acetyl-para-aminophenol (APAP) containing color bodies or their precursors, the method comprising: a) forming a hot aqueous solution of the crude APAP; and b) subsequently contacting the hot solution with an acid washed adsorbent carbon, e.g., an activated carbon, which acid washed carbon, prior to such contact, has been pretreated by contacting it with an aqueous solution of a reducing sulfite.
摘要:
A method is provided for purifying a crude N-acetyl-para-aminophenol (APAP) containing color bodies or their precursors, the method comprising: a) forming a hot aqueous solution of the crude APAP; and b) subsequently contacting the hot solution with an acid washed adsorbent carbon, e.g., an activated carbon, which acid washed carbon, prior to such contact, has been pretreated by contacting it with an aqueous solution of a reducing sulfite.
摘要:
2-(4-Isobutylphenyl)-propionic acid is purified by subjecting it to a vacuum rectification, in which the temperature is below the decomposition temperature of the acid.