METHOD OF PRODUCTION OF ACETIC ACID BY CARBONYLATION IN THE PRESENCE OF IRIDIUM CATALYST Russian patent published in 2002 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: method is performed by feeding methanol and/or its reactive derivative and carbon monoxide into carbonylation reactor containing a liquid reaction mixture. Part of a liquid reaction mixture is removed from the carbonylation reactor and added its if necessary after heating to the zone of a single equilibrium evaporation where vaporous and liquid fractions are obtained. The vaporous fraction comprises water, acetic acid, propionic acid, methyl acetate, methyl iodide and precursors of propionic acid. The liquid fraction comprises iridium catalyst, optional promoter, acetic acid and water. Liquid fraction is returned into reactor. The vaporous fraction is added in the first zone of distillation from that in the point locating over the point of vapor fraction addition to the zone of a single equilibrium evaporation the recirculating flow of light fraction including water, methyl acetate, methyl iodide, acetic acid and propionic acid precursors is removed and then returned into carbonylation reactor. Technological flow including acid produced, propionic acid as a by-site product and water are removed from the first distillation zone in the point located over the point of addition of vapor fraction to the zone of a single equilibrium evaporation. Method provides the production of acetic acid containing propionic acid and water in the amounts less 400 ppm and less 1500 ppm, respectively, as impurities. EFFECT: improved method of production, enhanced purity. 18 cl, 3 dwg, 1 tbl, 5 ex