PURPOSE: To obtain the titled compound useful as a raw material of polymers having excellent heat resistance, easily in high purity, by adding hydrochloric acid to crude bis[4-(aminophenoxy)phenyl]sulfone, dissolving the compound in warm water, and cooling the solution.
CONSTITUTION: Crude bis[4-(aminophenoxy)phenyl]sulfone is dissolved in water containing 1.0W5.0mol, based on 1mol of the sulfone, of hydrogen chloride by heating at 50W100°C. The solution is cooled, and the precipitated bis[4-(aminophenoxy)phenyl]sulfone hydrochloride is separated, and dissolved again in warm water. The solution is if necessary added with activated carbon and filtered to separate the insoluble impurities, and neutralized with an alkaline aqueous solution to obtain the objective compound.
HAMANO KAZUO
OGATA EIJI
