Cyclohexanone is the organic compound with the formula (CH
2)
5CO. The molecule consists of six-carbon
cyclic molecule with a
ketone functional group. This colorless oil has an odor reminiscent of peardrop sweets as well as
acetone.
Over time, samples assume a yellow color due to oxidation.
Cyclohexanone is slightly soluble in water, but miscible with common
organic solvents. Billions of kilograms are produced annually, mainly as
a precursor to
nylon.
[5]
Production
Cyclohexanone is produced by the oxidation of cyclohexane in air, typically using cobalt catalysts:
[5]
- C6H12 + O2 → (CH2)5CO + H2O
This process co-forms
cyclohexanol, and this mixture, called "
KA oil" for ketone-alcohol oil, is the main feedstock for the production of
adipic acid. The oxidation involves radicals and the intermediacy of the
hydroperoxide C
6H
11O
2H. In some cases, purified cyclohexanol, obtained by hydration of
cyclohexene, is the precursor. Alternatively, cyclohexanone can be produced by the partial
hydrogenation of
phenol:
- C6H5OH + 2 H2 → (CH2)5CO
This process can also be adjusted to favor the formation of cyclohexanol.
[5]
Uses:
The great majority of cyclohexanone is consumed in the production of precursors to
Nylon 6,6 and
Nylon 6. About half of the world's supply is converted to
adipic acid, one of two precursors for
nylon 6,6. For this application, the KA oil (see above) is oxidized with
nitric acid. The other half of the cyclohexanone supply is converted to the
oxime. In the presence of
sulfuric acid catalyst, the oxime
rearranges to
caprolactam, a precursor to
nylon 6:
[5]
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