Patent ID: 6140534
Filing Date: 2000-10-31
Classification: C07C

Abstract:
A method for purifying crude isophthalic acid (Ifrom a liquid dispersion thereof also containing impurities selected from unreacted starting materials, solvent, products of side reactions and/or other undesired materials comprising:filtering said dispersion to form a crude IPA filter cake;dissolving said filter cake in a selective crystallization solvent at an elevated temperature of from between about 50 and about 200.degree. C. to form a solution;crystallizing purified IPA from said solution in said crystallization solvent by reducing the temperature or reducing the pressure sufficient to flash evaporate solvent from said IPA of said solution;separating said crystallized purified IPA from said solution;washing the purified IPA cake with a clean or IPA saturated solvent to displace the mother liquor and color bodies; andre-dissolving or soaking the washed IPA cake in water at elevated temperatures.