Patent ID: 8304587

Claim:
A process for purifying a crude ethanol product, the process comprising the steps of: hydrogenating an acetic acid feed stream in a reactor in the presence of a catalyst to form a crude ethanol product; separating at least a portion of the crude ethanol product in a first column into a first distillate comprising ethanol, water and ethyl acetate, and a first residue comprising acetic acid; separating at least a portion of the first distillate in a second column into a second distillate comprising ethyl acetate and a second residue comprising ethanol and water, wherein the second column is an extractive distillation column; feeding an extraction agent to the second column; and separating at least a portion of the second residue in a third column into a third distillate comprising ethanol and a third residue comprising water, 0.001 to 0.5 wt. % ethanol, 0.001 to 0.5 wt. % ethyl acetate, and 0.001 to 0.5 wt. % acetic acid; wherein the extraction agent comprises at least a portion of the third residue.