Process for removing impurities from the mixture of cyclohexanone and cyclohexanol.

摘要

In a process for removing impurities from a mixture containing cyclohexanone and cyclohexanol produced by oxidizing cyclohexanone, comprising (a) feeding a mixture of cyclohexanone and cyclohexanol to a first distillation column in which low-boiling components are distilled off; (b) feeding the bottom of the first distillation column to a second distillation column in which cyclohexanone is distilled off; (c) feeding the bottom of the second distillation column to a third distillation column in which components consisting mainly of cyclohexanol are removed off; and (d) circulating the distillate of the third distillation column into the first distillation column via a dehydrogenation zone; the improvement which comprises: (e) the overhead pressure of the first, second and third distillation columns is maintained at 20 to 400 Torr; (f) part of the bottom of the second distillation column is supplied to a fourth distillation column of an overhead pressure of 500 to 2,500 Torr, in which lower-boiling components are removed off; (g) the distillate of the fourth distillation column is circulated into at least one of the steps selected from the group consisting of the first distillation column, the second distillation column, the third distillation column and the dehydrogenation zone; and (h) the bottoms of the third and fourth distillation columns are removed from the circulation system. ;