Metal-Catalyzed Liquid-Phase Auto-oxidation

3 METAL-CATALYZED LIQUID-PHASE AUTO-OXIDATION [Pg.244]

Metal-catalyzed liquid-phase auto-oxidahon plays a critical role in the manufacture of monomers widely used in polymers such as nylon and polyester. As menhoned earlier, soluble salts of cobalt and manganese catalyze oxidation of cyclohexane by dioxygen to cyclohexanol and cyclohexanone. Cyclohexanol and cyclohexanone are oxidized by nitric acid to give adipic acid, one of the monomers of nylon 6,6. The oxidation by nitric acid is carried out in the presence of and ions to improve [Pg.244]

Nylon 6,6 is a condensahon polymer of adipic acid and hexamethylene diamine. As shown by Equation 8.3.2, part of the cyclohexanone can also be converted to the corresponding oxime. [Pg.244]

The oxime is converted to caprolactam, which undergoes ring-opening polymerization to give nylon 6. The structures of both nylon 6,6 and nylon 6 are described in Sechon 8.4, and both of these polymers hnd [Pg.244]

The oxidation of cyclohexanone by nitric acid leads to the generation of nitrogen dioxide, nitric oxide, and nitrous oxide. The first two gases can be recycled for the synthesis of nitric acid. This reduces the E factor of the overall oxidation process to some extent. Nitrous oxide, however, cannot be recycled. Furthermore, it is a greenhouse gas as well as an ozone depleter. It therefore cannot be emitted out in the atmosphere and must be removed. [Pg.245]

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