Oxidation of Cyclohexane (Cyclohexanone-Cyclohexanol and Adipic Acid)

Cyclohexane is oxidized in a liquid-phase process to a mixture of cyclohexanone and cyclohexanol (KA oil). The reaction conditions are 95–120°C at approximately 10 atmospheres in the presence of a cobalt acetate and orthoboric acid catalyst system. About 95% yield can be obtained:

KA oil is used to produce caprolactam, the monomer for nylon 6. Caprolactam is also produced from toluene through the intermediate formation of cyclohexane carboxylic acid.

Cyclohexane is also a precursor for adipic acid. Oxidizing cyclohexane in the liquid-phase at lower temperatures and for longer residence times (than for KA oil) with a cobalt acetate catalyst produces adipic acid:

Adipic acid may also be produced from butadiene via a carbonylation route. Adipic acid and its esters are used to make nylon 6/6. It may also be hydrogenated to 1,6-hexanediol, which is further reacted with ammonia to hexamethylenediamine.

Hexamethylenediamine is the second monomer for nylon 6/6.