Nylon cyclohexanone oxime

Beckmann rearrangement of cvc7ohexanone oxime. M.p. 68-70 C, b.p. I39 C/12 mm. On healing it gives polyamides. Used in the manufacture of Nylon[6]. Cyclohexanone oxime is formed from cyclohexane and niirosyl chloride. U.S. production 1978 410 000 tonnes, capryl alcohol See 2-octanol. caiH Uc acid See oclanoic acid. 

Ingredients. Nylon-6 is produced commercially from caprolactam [105-60-2] which is the most important lactam industrially. AH industrial production processes for caprolactam are multistep and produce ammonium sulfate [7783-20-2] or other by-products. Approximately 95% of the world s caprolactam is produced from cyclohexanone oxime [100-64-1] via the Beckmann rearrangement (144). The starting material for cyclohexanone can be... 

Caprolactam [105-60-2] (2-oxohexamethyleiiiiriiQe, liexaliydro-2J -a2epin-2-one) is one of the most widely used chemical intermediates. However, almost all of the aimual production of 3.0 x 10 t is consumed as the monomer for nylon-6 fibers and plastics (see Fibers survey Polyamides, plastics). Cyclohexanone, which is the most common organic precursor of caprolactam, is made from benzene by either phenol hydrogenation or cyclohexane oxidation (see Cyclohexanoland cyclohexanone). Reaction with ammonia-derived hydroxjlamine forms cyclohexanone oxime, which undergoes molecular rearrangement to the seven-membered ring S-caprolactam. 

The most important use of cyclohexanone is as a chemical intermediate in nylon manufacture 97% of all cyclohexanone output is used either to make caprolactam for nylon-6, or adipic acid for nylon-6,6. In the caprolactam process cyclohexanone is converted to cyclohexanone oxime (mp,... 

Caprolactam is preferred to w-aminocaproic acid for the manufacture of nylon 6 because it is easier to make and to purify. Over the years many routes for the manufacture of caprolactam itself have been developed and major commercial routes are summarised in Figure 18.6. Of these routes the bulk of manufacture is via cyclohexanone and cyclohexanone oxime. 

Another valuable rearrangement reaetion that is usually catalysed by stoichiometric amounts of catalyst is the Beekmann rearrangement (Seheme 1.4). This reaetion is used commercially for converting cyclohexanone oxime into caprolactam, a key intermediate for nylon 6 20% oleum is the usual catalyst. A wide range of heterogeneous catalysts have been explored, which avoid the need for using oleum. In particular, certain... 

Sticking with nylon production, high-silica pentasil zeolites are used by Sumitomo to overcome environmental issues associated with the conversion of cyclohexanone oxime to caprolactam (Chapter 1, Scheme 1.4). 

The stereochemical use of the Beckmann rearrangement in assigning configuration to ketoximes has already been referred to, and it also has a large-scale application in the synthesis of the textile polymer Nylon-6 from cyclohexanone oxime (78) via the cyclic amide (lactam, 79) ... 

Cyclohexanone is thus converted to cyclohexanone oxime, an intermediate in the manufacture of Nylon-6. The catalyst is titanium silicalite-2. Commercialized by Enichem who built a 12,000 ton/year plant in Porta Marghera in 1994. 

PNC [Photonitrosation of cyclohexane] A photochemical process for making caprolactam (a precursor for nylon) from cyclohexane, nitrosyl chloride, and hydrogen chloride. The first photochemical product is cyclohexanone oxime ... 

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. 

Like imines, some oximes are known to undergo metabolic hydrolysis by a nonenzymatic mechanism. Cyclohexanone oxime (11.69), an intermediate in the synthesis of polycaprolactam or Nylon-6, is a good example with which to begin our discussion. Following administration to male rats by various routes, cyclohexanone oxime undergoes rapid metabolism, and only trace amounts of the parent compound can be recovered in the urine [104], Although cyclohexanone (11.70) represented a small fraction of the urinary metabolites, most of the dose was recovered as glucuronides of cyclohexa-nol (11.71) and of cis- and /ran.v-cyclohexanc-1,2-diol. 

Pyrrolidone is a lactone used for the production of nylon-4. This reactant may be produced by the reduction ammoniation of maleic anhydride. s-Caprolactam, used in the production of nylon-6, may be produced by the Beckman rearrangement of cyclohexanone oxime (structure 17.11). The oxime may be produced by the catalytic hydrogenation of nitrobenzene, the photolytic nitrosylation of cyclohexane (structure 17.9), or the reaction of cyclohexanone and hydroxylamine (structure 17.10). Nearly one-half of the production of caprolactam is derived from phenol. 

Nylon 6 can be prepared by polymerization of l-aza-2-cycloheptanone (e-caprolactam), obtained through the Beckmann rearrangement of cyclohexanone oxime (Section 24-3C) ... 

Several oxidative routes are available to change cyclohexane to cyclohexanone, cyclohexanol, and ultimately to adipic acid or caprolactam. If phenol is hydrogenated, cyclohexanone can be obtained directly this will react with hydroxylamine to give cyclohexanone oxime that converts to caprolactam on acid rearrangement. Cyclohexane can also be converted to adipic acid, then adiponitrile, which can be converted to hexamethylenedi-amine. Adipic acid and hexamethylenediamine are used to form nylon 6,6. This route to hexamethylenediamine is competitive with alternative routes through butene. 

The rearrangement of cyclohexanone oxime to caprolactam is still an important step in nylon production, and the heterogeneously catalyzed Beckmann rearrangement has been extremely well investigated (4, 16-19). In order to obtain catalysts that couple a high lactam selectivity to long lifespan, careful tuning of the zeolite properties is required. Some important factors are ... 

Caprolactam (6-hexanolactam), used in nylon production, can be made from aniline, by hydrogenation to cyclohexamine in the presence of a nickel-cobalt catalyst. The amine is then converted to cyclohexanone oxime. 

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... 

E-Caprolactam is an important starting material for the production of nylon-6. It is synthesized by the Beckmann rearrangement reaction of cyclohexanone oxime catalyzed by a solid acid catalyst. Many solid acid catalysts, such as mixed boron oxide [1-3], Si02-Al203 [4,5], metal phosphates [6-8] and moclified zeolites [3,9-12], are reported to catalyze the cycdohexanone oxime rearrangement. The acid function of the catalyst is essential to effect the rearrangement reaction. 

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. 

Cyclohexanone, a six-membered carbon ring with a ketone as functional group, is almost exclusively applied as a precursor for the production of aliphatic polyamides. Pure cyclohexanone is mainly converted, via cyclohexanone oxime and caprolactam, to nylon-6 (also called polycaprolactam) [1]. Mixtures of cyclohexanone and cyclohexanol, often called K4 oil, are converted via oxidation into adipic acid that reacts with hexamethylene diamine (HMDA) to nylon-6,6 (poly-hexamethylene adipamide). Other applications of these products can be found in the field of polyurethane and polyester production. 

---