Patent ID: 8501990

Claim:
A process for removing permanganate reducing compounds (PRC's) from a carbonylation product, the process comprising the steps of: (a) separating the carbonylation product produced by a carbonylation process to provide a first vapor stream comprising acetic acid and a less volatile catalyst phase; (b) distilling the first vapor stream to yield a first sidestream comprising acetic acid and a second vapor stream comprising methyl iodide, methyl acetate, and at least one PRC; (c) condensing the second vapor stream to form a condensate; (d) distilling at least a portion of the condensate in a single distillation column to form a third vapor stream and a higher boiling liquid phase residuum, wherein the third vapor stream is enriched with PRC's and methyl iodide with respect to the higher boiling liquid phase residuum; and (e) condensing the third vapor stream and extracting a portion of the condensed third vapor stream with an extractant to obtain an aqueous acetaldehyde stream comprising the at least one PRC and a raffinate comprising methyl iodide.