Process for making cyclohexanone

A process for making cyclohexanone, the process comprising the following steps:

• (I) feeding a first mixture comprising cyclohexanone, phenol, and cyclohexylbenzene into a first distillation column;
• (II) obtaining from the first distillation column:
• a first upper effluent comprising cyclohexanone at a concentration higher than in the first mixture, phenol, and cyclohexylbenzene;
• a first middle effluent comprising cyclohexanone, phenol at a concentration higher than in the first mixture, cyclohexylbenzene, and bicyclohexane;
• and
• a first lower effluent comprising cyclohexylbenzene at a concentration higher than in the first mixture;
• (III) feeding at least a portion of the first middle effluent and hydrogen into a hydrogenation reaction zone where phenol reacts with hydrogen in the presence of a hydrogenation catalyst under hydrogenation reaction conditions to obtain a hydrogenation reaction product comprising cyclohexanone at a concentration higher than in the first middle effluent, phenol at a concentration lower than the first middle effluent, cyclohexylbenzene, and bicyclohexane;
• (IV) feeding at least a portion of the hydrogenation reaction product to the first distillation column;
• (V) feeding at least a portion of the first upper effluent into a second distillation column;
• and
• (VI) obtaining the following from the second distillation column:
• a second upper effluent comprising cyclohexanone at a concentration higher than in the first upper effluent;
• and
• a second lower effluent comprising cyclohexanone at a concentration lower than the first upper effluent, and cyclohexanol at a concentration higher than in the first upper effluent;
• wherein at least a portion of the heat supplied to the second distillation column is provided by a liquid stream drawn from the first distillation column.