REMOVAL OF PERMANGANATE REDUCING COMPOUNDS AND ALKYL IODIDES FROM A CARBONYLATION PROCESS STREAM

摘要

PURPOSE: A method for manufacturing high purity acetic acid is provided. Permanganate reducing compounds and alkyl iodides can be conveniently removed from a light phase of an intermediate stream in the reaction process by employing a multiple distillation process coupled with an optional extraction of acetaldehyde. CONSTITUTION: A distillation process involves first distilling a light phase to concentrate the permanganate reducing compounds, and in particular the acetaldehyde, and then separating the permanganate reducing compounds and alkyl iodides in a second distillation tower. The second distillation serves to remove the permanganate reducing compounds and alkyl iodides from methyl iodide, methyl acetate, and methanol mixture. As an optional third step, the twice distilled stream can be directed to an extractor to remove any remaining quantities of methyl iodide from the aqueous acetaldehyde stream to obtain acetic acid as a final product in greater than 99 % purity.