Cyclohexanone oxime ammoximation production

The TS-1 catalysed ammoximation of cyclohexanone with NH3/H2O2 is a new process (Romano et ai, 1990) for the production of cyclohexanone oxime, the precursor of caprolactam. In the existing process, the oxime is produced by reaction of cyclohexanone... 

The oxidation of NH3 to NH2OH forms the basis of a process for the ammoximation of cyclohexanone to the oxime because the NH2OH formed in solution readily reacts with the ketone (non-catalytically) to give the oxime (231). Table XXX (165) illustrates the conversions and selectivites obtained for a few typical ketones and aldehydes. The ammoximation of aldehydes is faster than that of ketones. The oxime selectivity is also higher. The ammoximation of cyclohexanone by this method offers a more eco-friendly alternative route to the cyclohexanone oxime intermediate for the production of Nylon-6. The current route coproduces large quantities of ammonium sulfate and involves the use of hazardous chemicals such as oleum, halides, and oxides of nitrogen. 

Recently, the Sumitomo Chemical Co., Ltd. developed the vapour-phase Beckmann rearrangement process for the production of 8-caprolactam. In the process, cyclohexanone oxime is rearranged to e-caprolactam by using a zeolite as a catalyst instead of sulfuric acid. EniChem in Italy developed the ammoximation process that involves the direct production of cyclohexanone oxime without producing any ammonium sulfate. The Sumitomo Chemical Co., Ltd. commercialized the combined process of vapour-phase Beckmann rearrangement and ammoximation in 2003 ". 

The TS-1 catalyzed hydroxylation of phenol to a 1 1 mixUne of catechol and hydroquinone has been commercialized by Enichem. Similarly, the ammoximation of cyclohexanone is being developed commercially as a low-salt alternative to the conventional process for the production of cyclohexanone oxime, the raw material for nylon-6. The reaction involves initial TS-1 catalyzed oxidation of NH3 by HjOj to give NH2OH. The fact that bulky ketones such as cyclododecanone undergo ammoximation is consistent with subsequent reaction of NHjOH with the ketone substrate taking place outside the molecular sieve. The method has been used [49] for the conversion of p-hydroxyacetophenone to the corresponding oxime which is the precursor of the analgesic paracetamol (Reaction 13). 

Cyclohexanone oxime is an important intermediate for the production of caprolactam and nylon-6 (1). Recently, attention has been focused on a new reaction for its synthesis, called ammoximation whereby the cyclohexanone is transformed into the oxime by reaction with... 

Another reaction commercialized by EniChem is the ammoximation of ketones, particularly the conversion of cyclohexanone to cyclohexanone oxime (47). This latter compound is an intermediate in the manufacturing of caprolactam, the monomer for Nylon 6. This reaction, outlined in Figure 10.13, proceeds with both high conversion and selectivity for the oxime product. Again, TS-1 is uniquely active for this reaction compared to other catalysts, and TS-1 can catalyze this reaction on a variety of substrates. It is believed that in all cases the hydroxylamine is first formed, followed by reaction with the ketone. TS-1 is currently used commercially by EniChem to produce 12,000 ton per year of cyclohexanone oxime. 

Production of cyclohexanone oxime through cyclohexanone ammoximation... 

The direct ammoximation of cyclohexanone has been performed with hydrogen peroxide and ammonia using a catalyst based on TS-1 (5a). Good performance was obtained, with water as the only side product. EniChem built a 12,000 t/yr demonstration plant (300), which has been running successfully since 1994. Sumitomo built a unit with a capacity of60,000 t/yr in 2003 and both companies plants have operated without any major problems. (232) Sumitomo (301) commercialized its process, in combination with a zeohte-catalyzed Beckmann rearrangement of cyclohexanone oxime... 

A new, highly innovative process for the production of cyclohexanone oxime, an intermediate in CPL production, has been described. The ammoximation reaction proceeds via a hydroxylamine intermediate, which is formed by the oxidation of ammonia with hydrogen peroxide and catalyzed by TiS. 

The hrst step of the integrated process, the ammoximation of cyclohexanone to cyclohexanone oxime, is based on a reaction, catalyzed by TS-1, between cyclohexanone, ammonia and hydrogen peroxide. It completely eliminates, on the one hand, the problems linked with the production and use of hydroxylamine and, on the other, the co-production of sulfates. 

A process based on the ammoximation of cyclohexanone and on the catalyzed rearrangement of the oxime went on stream in Japan in 2003 it allows the salt-free production of s-caprolactam, at lower investment and operating costs than by conventional routes. 

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