Recovery of butanol from a mixture of butanol, water, and an organic extractant

A process comprising the steps:

• a) introducing a feed comprising:
• (i) a water-immiscible organic extractant;
• (ii) water;
• (iii) at least one isomer of butanol;
• (iv) optionally a non-condensable gas;
• (v) ethanol;
• and
• (vi) optionally fermentation by-products
• into a first distillation column,
• wherein the first distillation column comprises a stripping section and optionally a rectifying section at an introduction point above the stripping section, the first distillation column having an operating temperature, T1 and an operating pressure P1 in the stripping section;
• wherein T1 and P1 are selected to produce a first bottoms stream and a first vaporous overhead stream, the first bottoms stream comprising the water-immiscible organic extractant, butanol, and ethanol and being substantially free of water, and the first vaporous overhead stream comprising water, butanol, ethanol, optionally the extractant, and optionally the non-condensable gas;
• b) introducing a water-immiscible organic entrainer to at least one appropriate process stream or vessel;
• c) condensing the first vaporous overhead stream to produce a gas phase and recover a mixed condensate, wherein the mixed condensate comprises:
• (i) an organic phase comprising butanol, ethanol, entrainer, and water;
• and
• (ii) an aqueous phase comprising water, butanol, ethanol;
• and
• wherein the mixed condensate comprises sufficient entrainer to provide phase separation of the organic and the aqueous phases;
• d) introducing at least a portion of the organic phase to the first distillation column;
• and
• e) introducing at least a portion of the first bottoms stream into a second distillation column having at least a stripping section and optionally a rectifying section and operating the second distillation column to produce a second bottoms stream comprising the extractant, and a second vaporous overhead stream comprising butanol and ethanol.