METHOD OF PREPARING ISOPHTHALIC ACID Russian patent published in 2001 - IPC

FIELD: chemistry of polymers, more particularly preparation of chemical fibers, polyester film, varnishes, coloring agents, and plastic materials. SUBSTANCE: invention makes it possible to increase efficiency of withdrawal of reaction water and to improve quality of isophthalic acid by using catalyst which comprises zinc and nickel salts or mixture of said metal salts at (Co+Mn): HT ratio of 1:0.01-0.2, and content of water in oxidation zone is regulated by three-step cooling of vapor-gas mixture going out of reactor in direct flow of gas condensed CH₃COOH-H₂O vapors in first and third stages and counterflow in second stage in combination with rectification process and subsequently recycling dehydrated stream of liquid acetic acid from first and second cooling stages into oxidation zone, withdrawing dehydrated acetic and out of process from third cooling stage in ratio that allows for water concentration of 4-10% in reaction zone. After additional oxidation of impurities, isophthalic acid is treated with acetic acid or with acetic acid and water at 170-230 C. EFFECT: more efficient preparation method. 2 cl, 1 dwg, 1 tbl