FIELD: industrial organic synthesis. SUBSTANCE: crude terephthalic acid is purified from its liquid dispersion containing impurities, in particular unreacted reactants, solvents, by-products, and other undesired impurities, by filtering dispersion to give filtered precipitate of crude terephthalic acid. The latter is dissolved in selective crystallization solvent at 50 to 250 C to form solution, from which terephthalic acid is crystallized at lowered temperature. Crystallized terephthalic acid is separated and redissolved in selective crystallization solvent to form second solution, from which second-stage terephthalic acid is crystallized at temperature and pressure lowered in sufficient degree to provide flash evaporation of solvent, temperature not being lowered below 50 C. Thus recrystallized terephthalic acid is washed with water, soaked in water at temperature within a range of 150-300 C, filtered, and dried. Other purification options are offered. EFFECT: increased purity of product and improved economic and ecological characteristics of process. 34 cl, 10 dwg, 11 tbl, 7 ex
