Patent ID: 7855306
Filing Date: 2010-12-21
Classification: C07C

Abstract:
1. A process for the reduction and/or removal of permanganate reducing compounds (PRC's) formed in the carbonylation of a carbonylatable reactant to produce a carbonylation product comprising acetic acid, comprising the steps of: (a) separating the carbonylation product to provide a vapor overhead stream comprising acetic acid and a less volatile catalyst phase; (b) distilling the vapor overhead stream to yield a purified acetic acid product and a low boiling overhead vapor stream comprising methyl iodide, water, acetic acid, methyl acetate, and at least one PRC; (c) condensing the low boiling overhead vapor stream and biphasically separating it to form a condensed heavy liquid phase and a condensed light liquid phase; (d) distilling the condensed light liquid phase in a single distillation column to form a second vapor phase stream overhead and a higher boiling liquid phase residuum, wherein the second vapor phase stream is enriched with PRC's with respect to the condensed light liquid phase; and (e) condensing the second vapor phase stream and extracting the condensed stream with water to obtain an aqueous acetaldehyde stream comprising PRC and a raffinate comprising methyl iodide.