METHOD OF PURIFYING ACETIC ACID AND/OR ACETIC ANHYDRIDE FROM IODIDES ADMIXTURES Russian patent published in 1997 - IPC

FIELD: chemical engineering; acetic acid production. SUBSTANCE: purification of acetic acid and/or acetic anhydride fraction obtained through liquid-phase carbonization of methanol or methyl acetate in presence of carbonization catalyst, iodine-containing promoter, and iodine-containing copromoter consists in evaporating the fraction, after starting material and promoter components have been removed, to produce vapor acid and/or anhydride fraction with reduced iodide content. The process is carried out in a flash-evaporator provided, in its top part, with a scrubber section wherein catalyst-containing distillate is collected, whereas other admixtures and nonreacted starting material are removed from the bottom of apparatus . Distillate is transferred into distillation column, and still residue containing contaminated acetic acid is entered into the last flash evaporator wherefrom purified acetic acid vapor is withdrawn. EFFECT: enhanced efficiency of process. 7 cl, 2 dwg, 4 tbl