METHOD OF REMOVING CORROSIVE METALS FROM CARBONYLATION CATALYST SOLUTIONS

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FIELD : chemistry. SUBSTANCE : invention relates to a method for liquid-phase carbonylation of reagent capable of carbonylation, selected from methanol and/or its reactive derivative to obtain a carbonylated product selected from acetc acid, acetic anhydride and their mixtures, involving bringing the reagent capable of carbonylation into contact with carbon monoxide in a liquid reaction composition in a reaction zone, where the said liquid reaction composition contains a carbonylation catalyst selected from iridium, rhodium and their mixtures, methyl iodide, salts of an alkali metal or alkali-earth metal, capable of generating iodide ions and corrosive metal impurities, where the liquid reaction composition is separated in a single equilibrium evaporation zone to obtain a vapour fraction containing a carbonylated product and a liquid fraction containing a carbonylation catalyst solution, where the said carbonylation catalyst solution contains a carbonylation catalyst, an alkali or alkali-earth metal and corrosive metal impurities, and where at least a portion of the carbonylation catalyst solution is returned to the reaction zone. The carbonylation catalyst solution returned to the reaction zone has low content of corrosive metal impurities and concentration of alkali or alkali-earth metal in the liquid reaction composition is controlled by bringing into contact at least a portion of the carbonylation catalyst solution with a cation-exchange resin whose active portions are partially saturated by a sufficient amount of alkali or alkali-earth metal. EFFECT : obtaining carbonylation catalyst solution with low content of corrosive metal impurities with retention of concentration of alkali and/or alkali-earth metal in the catalyst solution at the same time. 20 cl, 13 ex, 2 tbl, 2 dwg