Abstract: A process for producing ethanol comprising the steps of hydrogenating an acetic acid feed stream to form a crude ethanol product and separating at least a portion of the crude ethanol product to form an ethanol stream and at least one vent stream. The vent stream comprises non-condensable gases at least one volatile organic. The process further comprises the step of scrubbing the vent stream with at least two different solvents to recover the volatile organics. The vent stream may also comprise entrained ethanol, which may also be recovered.

Abstract: An improvement of the methanol carbonylation process for manufacturing acetic acid is disclosed. Specifically disclosed is a method for removing permanganate reducing compounds (“PRC's”) from the condensed light ends overhead stream, including (a) distilling at least a portion of the condensed light ends overhead to yield a PRC enriched second overhead stream; (b) extracting the second overhead stream with water and separating therefrom an aqueous stream containing PRC's; and (c) returning at least a portion of the extracted second overhead to the second distiller.

Abstract: A method is provided to improve the quality of recycle of certain residues by modifying the separation of alkanes and alkane-like materials and carbonyl-containing impurities from the recycle during the manufacture of acetic acid by the carbonylation of methanol. The improvement comprises operating a prior art stripper column in a reflux manner and partitioning the residue therefrom by the addition of water. The method also reduces the volume of disposal of potentially valuable recyclable reactants.