METHOD OF PRODUCING ISOPHTHALIC ACID AND FORMIC ACID BY OXIDATION OF m-DIISOPROPYLBENZENE AND m-ETHYL-ISOPROPYLBENZENE Russian patent published in 2013 - IPC C07C63/24 C07C27/12 C07C51/265 C07C51/43 C07C51/48 C07C51/46 C07C53/02 

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of organic and petrochemical synthesis, specifically to the technology of producing isophthalic acid and a by-product - formic acid by liquid-phase oxidation with O₂ gas in the medium of acetic acid in the presence of a Co and Mn salt catalyst at high temperature and pressure, followed by extraction of isophthalic acid and purification thereof by recrystallisation in a water-acetic solvent, extracting formic acid by distillation from the anhydrous acetic acid condensate formed when cooling the vapour-gas mixture removed from the reaction zone with spent air, where there is oxidation of m-diisopropylbenzene or m-ethyl-isopropylbenzene in three steps while raising temperature in steps in the range of (°C) 130-150; 140-160; 165-185°C, pressure (MPa) 0.3-0.6; 0.6-0.8; 0.9-1.2, overall concentration of the Co-Mn-Ni catalyst (ppm) 800 - 1060; 1000 - 1435; 1250 - 1744; and during air flow through the oxidation zone, concentration of CO/CO₂ in the spent gas after each step is kept in the following ranges (vol. %): 0.16, 0.17, 0.18-0.25, 0.26 / 0.24, 0.25, 0.9-1.12, 1.19, 1.20, 1.21; 0.18, 0.2-0.3 / 0.9, 1.1-1.42; 0.2, 0.23-0.42 / 1.15, 1.2-1.6,1.8; 93.2-98.8% content of isophthalic acid in oxidation products extracted from the cooled oxidation product of step 3 is achieved, after which process isophthalic acid is purified by successive recrystallisation in CH₃COOH while heating the suspension to 180-200°C, and then in H₂O while heating the suspension to 200-230°C to obtain highly pure isophthalic acid, and formic acid formed during the oxidation process is extracted from the vapour-gas mixture from the oxidation reactor by cooling the vapour-gas mixture to 30-40°C, separating the formed condensate and treatment thereof with n-butyl acetate in ratio of acid to n-butyl acetate of 1:0.17; further, reaction water in form of its azeotropic mixture with n-butyl acetate and then formic acid and acetic acid are successively extracted from the obtained mixture by fractionation.

EFFECT: method enables to obtain to commercial products - aromatic isophthalic acid and aliphatic formic acid and increases output of the end products.

3 cl, 1 dwg, 2 tbl, 11 ex