ε-カプロラクタム製造法の推移

抄録

The manufacture of ε-caprolactam is carried on by means of three processes at present. The first process was developed by IG Farben, at which the first industrial production of ε-caprolactam was begun in 1943. The starting material is phenol, from which cyclohexanone is produced, and then converted to the corresponding oxime. Hydoxylamine is produced by Raschig method. The oxime is transformed into ε-caprolactam by Beckmann rearrangement in oleum. Major amount of ε-caprolactam in the world is manufactured still by this process, which is, however, somewhat modified. The modifications differ with manufacturers. Phenol may be replaced with cyclohexane which is converted to cyclohexanone by air oxidation. Hydroxylamine can be produced also by reduction of either nitrogen monoxide or nitric acid. The second process was developed by Snia Viscosa in 1962. The starting material is toluene, which is converted into cyclohexane carboxylic acid. The treatment of the acid with nitrosyl sulfuric acid in oleum yields ε-caprolactam. The third process was developed by Toyo Rayon (now, Toray) in 1963. The method consists of the photo-reaction of cyclohexane with nitrosyl chloride giving cyclohexanone oxime hydrochloride, which is rearranged in oleum to ε-caprolactam.
The ε-caprolactam manufacture is historically reviewed.