Patent ID: 8912358

Claim:
A method for producing acetic acid comprising: (a) reacting methanol and carbon monoxide in the presence of a carbonylation catalyst, a catalyst stabilizer, methyl iodide, water and methyl acetate to produce an acetic acid stream comprising a hydrocarbon impurity; (b) flashing the acetic acid stream into a vapor stream comprising acetic acid, water, methanol, methyl acetate, methyl iodide and the hydrocarbon impurity, and a liquid stream comprising the catalyst and the catalyst stabilizer; (c) separating the vapor stream from step (b) by distillation into a product stream comprising acetic acid and water, and an overhead stream, wherein the overhead stream comprises: (i) from about 60 to 90 wt. % methyl iodide, (ii) water, (iii) methyl acetate, (iv) acetic acid, and (v) the hydrocarbon impurity; (d) condensing the overhead stream from step (c) into a light, aqueous phase comprising water, and acetic acid, methyl acetate, and a heavy, organic phase comprising methyl iodide, acetic acid, water, and the hydrocarbon impurity; and (e) distilling the heavy, organic phase from step (d) into a vapor stream comprising methyl iodide and a bottoms stream comprising acetic acid, methyl iodide, water, and the hydrocarbon impurity; and (f) extracting the bottoms stream from step (e) with a mixture comprising about 50 to about 95%, by volume, of a hydrocarbon extracting agent and about 5 to about 50%, by volume, of water, and forming a light phase comprising the hydrocarbon impurity and the extracting agent and a heavy phase comprising methyl iodide, water, and acetic acid wherein the hydrocarbon extracting agent is a C 9 to C 20 aromatic or paraffinic hyrdocarbon.