RU98108500A - METHOD FOR PRODUCING ISOPHTHALIC ACID - Google Patents

Claims (2)

1. A method of producing isophthalic acid (IFC) by liquid-phase oxidation of m-xylene with an oxygen-containing gas in an acetic acid medium at elevated temperature and pressure in the presence of catalysts consisting of cobalt, manganese and bromide salts, regulating the water content in the oxidation zone, followed by further oxidation of impurities and treatment with acetic acid using recycle of the mother liquor after the separation of IFC from acetic acid solutions to the I or II stage, characterized in that the catalyst additionally contains neighs zinc, nickel salts or a mixture of the indicated metal salts [MT] with the ratio [Co + Mn]: [MT] = 1: 0.01 ^o C0.2, and the water content in the oxidation zone is controlled by three-stage cooling of the vapor-gas mixture leaving the reactor under the conditions of the direct flow of gas and condensed vapors CH ₃ COOH - Н ₂ O - at the first and third stages and counterflow at the second stage in combination with a rectification process with the subsequent return of the dehydrated stream of liquid acetic acid in total from the first and second stages of cooling to the oxidation zone, from the process watered acetic acid from the third stage of cooling in a ratio providing a concentration of water in the reaction zone of 4-10%. 2. The method according to p. 1, characterized in that the processing of isophthalic acid after the oxidation of impurities is carried out with acetic acid or acetic acid and water at a temperature of 170-230 ^o C.