A system configured to separate a cleavage reaction mixture comprising phenol, cyclohexanone, an amine salt, cyclohexylbenzene, and water, the system comprising: (I-1A) a first fractionation column configured to receive at least a portion of the cleavage reaction mixture to produce a first lower effluent comprising the amine salt, and a first upper effluent comprising phenol, cyclohexanone and water; (I-1B) a second fractionation column in fluid communication with the first fractionation column configured to receive at least a portion of the first upper effluent to produce a second lower effluent comprising phenol and cyclohexanone, and a second upper effluent comprising water; (I-1C) a third fractionation column in fluid communication with the second fraction column configured to receive at least a portion of the second lower effluent and an extractive solvent to produce a third lower effluent comprising phenol and the extractive solvent, and a third upper effluent comprising at least 60 wt% of cyclohexanone, the percentage based on the total weight of the third upper effluent; (I-1D) an optional fourth fractionation column in fluid communication with the third fractionation column configured to receive at least a portion of the third upper effluent to produce a fourth lower effluent comprising components having normal boiling points higher than that of cyclohexanone, and a fourth upper effluent comprising at least 90 wt% cyclohexanone, the percentage based on the total weight of the fourth upper effluent; (I-1E) a fifth fractionation column in fluid communication with the third fractionation column configured to receive at least a portion of the third lower effluent to produce a fifth lower effluent comprising the extractive solvent, and a fifth upper effluent comprising at least 60 wt% of phenol, the percentage based on the total weight of the fifth upper effluent; and (I-1F) a sixth fractionation column in fluid communication with the fifth fractionation column configured to receive at least a portion of the fifth upper effluent to produce a sixth bottom effluent comprising cyclohexylbenzene, and a sixth upper effluent comprising at least 90 wt% of phenol, the percentage based on the total weight of the sixth upper effluent. (I-1A) a first fractionation column configured to receive at least a portion of the cleavage reaction mixture to produce a first lower effluent comprising the amine salt, and a first upper effluent comprising phenol, cyclohexanone and water; (I-1B) a second fractionation column in fluid communication with the first fractionation column configured to receive at least a portion of the first upper effluent to produce a second lower effluent comprising phenol and cyclohexanone, and a second upper effluent comprising water; (I-1C) a third fractionation column in fluid communication with the second fraction column configured to receive at least a portion of the second lower effluent and an extractive solvent to produce a third lower effluent comprising phenol and the extractive solvent, and a third upper effluent comprising at least 60 wt% of cyclohexanone, the percentage based on the total weight of the third upper effluent; (I-1D) an optional fourth fractionation column in fluid communication with the third fractionation column configured to receive at least a portion of the third upper effluent to produce a fourth lower effluent comprising components having normal boiling points higher than that of cyclohexanone, and a fourth upper effluent comprising at least 90 wt% cyclohexanone, the percentage based on the total weight of the fourth upper effluent; (I-1E) a fifth fractionation column in fluid communication with the third fractionation column configured to receive at least a portion of the third lower effluent to produce a fifth lower effluent comprising the extractive solvent, and a fifth upper effluent comprising at least 60 wt% of phenol, the percentage based on the total weight of the fifth upper effluent; and (I-1F) a sixth fractionation column in fluid communication with the fifth fractionation column configured to receive at least a portion of the fifth upper effluent to produce a sixth bottom effluent comprising cyclohexylbenzene, and a sixth upper effluent comprising at least 90 wt% of phenol, the percentage based on the total weight of the sixth upper effluent.