ABSTRACT
Cyclohexanol and cyclohexanone were produced commercially by the hydrogenation of phenol. The reaction is usually carried out in the liquid phase, although vapour-phase oxidation can be used. The cyclohexanol-cyclohexanone mixture can be separated by fractional distillation. Cyclohexane of 98% purity is oxidized to a mixture of cyclohexanol and cyclohexanone with air in a reactor at 90–120°C and a pressure of 10 bar. The organic phase containing the crude cyclohexanol-cyclohexanone mixture is treated with alkali to remove any remaining acids. Any unreacted cyclohexane is removed by fractionation at atmospheric pressure and recycled. The hydrogenation of phenol can be carried out in the liquid or vapour phase, the reaction products being determined by the catalyst used. Iron, mild steel or aluminium are usually used for storage containers as cyclohexanol has no appreciable corrosive effect on these metals. If water is present, which is often the case in some of the technical grades, then corrosion can occur.
