PROCESS FOR SEPARATING AND PURIFYING ALKALI METAL SALTS OF HYDROXY NAPHTHALENE CARBOXYLIC ACIDS

摘要

PURPOSE: A process for separating and purifying an alkali metal salt of 2-hydroxynaphthalene-3-carboxylic acid is provided which produces high pure compound without neutralization. CONSTITUTION: The process comprises the steps of dissolving a mixture of 2-hydroxynaphthalene-3-carboxylic acid and an alkali metal salt thereof in water or solvent consisting of water and a water-soluble organic solvent such as aromatic copolymers based on styrene and divinylbenzene or methacrylate copolymers based on monomethacrylate and dimethacrylate; introducing it into the upper part of a column charged with adsorbing a nonionic porous synthetic adsorbent; and dilluting at first with water or a water-soluble organic solvent rich in water and then with a solvent system rich in a water-soluble organic solvent to separate and purify the alkali metal salt of 2-hydroxynaphthalene-3-carboxylic acid, especially a salt of carboxylic acid.