METHOD FOR PREPARING ACETIC ACID BY CARBONYLATION OF METHANOL IN THE PRESENCE OF RHODIUM CATALYST (VARIANTS)

摘要

FIELD: chemical technology. SUBSTANCE: invention relates to preparing acetic acid. Method involves interaction of methanol with carbon monoxide in liquid medium containing catalytically effective amount of rhodium catalyst; from 0.1 to less 14 wt.-% of water; acetic acid; methyl iodide salt as effective stabilizing agent of catalyst and promoter that is soluble in reaction medium at reaction temperature taken in the amount providing maintenance of iodide ions concentration in the range 2- 20 wt.-%; 0.5-30 wt.-% of methyl acetate and the following isolation of acetic acid from preparing reaction product. Pollution of prepared acetic acid with carbonyl impurities is diminished by maintenance of methyl iodide concentration in the reaction course at level less 4.5 wt.-%. Salt represents iodide or acetate salts of quaternary ammonium or phosphonium or iodide or acetate salts of element from group including metals of IA and IIA Periodic system of elements. Also, invention proposes variants of method for preparing acetic acid. EFFECT: improved preparing method, reduced amount of impurities in acetic acid. 15 cl, 1 tbl