PURIFICATION OF CRUDE TETRAHYDROFURAN

PROBLEM TO BE SOLVED: To provide a method for efficiently recovering high-purity tetrahydrofuran at a low cost. SOLUTION: (a) Crude tetrahydrofuran is subjected to a contact treatment with water and/or acetic acid in the presence of a strongly acidic cation exchange resin and (b) the treated liquid is then fed to an acetic acid separation column and a water-tetrahydrofuran mixture is taken out of a side stream to distill off a water-tetrahydrofuran mixture containing components having a lower boiling point than that of the tetrahydrofuran from the column top. (c) The water-tetrahydrofuran mixture is subsequently hydrotreated in the presence of a noble metal-based catalyst and (d) the resultant hydrotreating reactional product is then subjected to gas-liquid separation and the liquid phase part is subsequently fed to an azeotropic dehydration column to take out the dehydrated tetrahydrofuran as a bottom product from the column bottom. (e) The obtained bottom product is fed to a product column to distill off the high-purity tetrahydrofuran from the column top and high-boiling substances are taken out as a bottom product from the column bottom. (f) The resultant bottom product is circulated and mixed with the raw material crude tetrahydrofuran.