Formation terephthalic acid by electrochemical acidification of a sodium terephthalate solution

摘要

A method for recuperating from saponification products of alkaline polyterephthalate with soda where both terephthalate ions are in acid form and the sodium ions are in the form of soda is disclosed. In this method the sodium terephthalate solution resulting from dissolving the saponification products are subjected to a step of electrochemical pre-acidification to bring the pH to 4 to 7. Thereafter an electrochemical acidification step by electrolysis is undertaken to precipitate the terephthalic acid in the anode section and recuperate the soda in the cathode section which can be recycled.