| abstract |
A method for purifying tetrahydrofuran from a liquid containing tetrahydrofuran and as impurities at least water, 2,5-dihydrofuran and butanol, the method comprising: a first distillation step in which the liquid is subjected to distillation using a distillation column to separate into a first bottoms product containing water as a major component and a first distillate containing tetrahydrofuran, 2,5-dihydrofuran and butanol as major components, a second distillation step in which the first distillate is subjected to distillation using a distillation column to separate into a second bottoms product containing tetrahydrofuran and butanol as major components and a second distillate containing 2,5-dihydrofuran as a major component, a third distillation step in which the second bottoms product is subjected to distillation using a distillation column to separate into a third bottoms product containing butanol as a major component and a third distillate containing tetrahydrofuran as a major component, and further comprising a recirculation step in which a part of the second top liquid is recirculated into the first distillation step as a recirculation liquid and the remaining part is discharged into the outside of the system. |