Page 245 - Chemical and process design handbook

Speight_Part II_C 11/7/01 3:08 PM Page 2.185

CYCLOHEXANE

o
Cyclohexane (hexahydrobenzene, melting point: 6.5 C, boiling point:
o
o
81 C, density: 0.7791, flash point: –20 C) can be quantitatively produced
from benzene by hydrogenation over either a nickel or a platinum catalyst
o
at 210 C and 350 to 500 psi hydrogen (Fig. 1).
C H + 3H → C H
6 6 2 6 12
Several reactors may be used in series and the yield is over 99 percent.
Cyclohexane is used for the manufacture of adipic acid and caprolac-
tam. Adipic acid is used to manufacture nylon 6,6, and caprolactam is the
monomer for nylon 6.

Gas
Soluble catalyst

Liquid-phase reactor Vapor-phase fixed-bed finishing reactor High-pressure separator High-pressure

Benzene separator

Hydrogen Cyclohexane

Purge gas
FIGURE 1 Manufacture of cyclohexane.

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