METHOD FOR PURIFICATION OF A AROMATIC DIACID OR THE CORRESPONDING ANHYDRIDES

摘要

A method of removing an aromatic carboxy-aldehyde from an aromatic acid or the corresponding anhydride includes reacting a hydroxylamine-containing compound with the aromatic carboxy-aldehyde to form a reaction mixture including the corresponding nitrone. A phthalic acid or corresponding anhydride prepared according to the method is also described herein. A method for the manufacture of a phenyl dicarboxylic acid includes oxidizing a xylene to provide a stream including the phenyl dicarboxylic acid and the corresponding carboxybenzaldehyde and toluic acid contaminants, reacting a hydroxylamine- containing compound with the carboxybenzaldehyde in the stream to form a reaction mixture including the corresponding nitrone, wherein the nitrone is water soluble, and crystallizing the phenyl dicarboxylic acid or the corresponding anhydride from water to provide the purified phenyl dicarboxylic acid or the corresponding anhydride. A phenyl dicarboxylic acid prepared according to the above method represents another embodiment.