Cyclohexanone oxime, rearrangement

Poisoning experiments (at 573 K) in cyclohexanone oxime rearrangement over APTi-E-31 catalyst... 

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. 

Cyclohexanone oxime is converted quantitatively to caprolactam by Beckmann rearrangement in the presence of oleum, which is of sufficient strength to consume the several percent water in the molten oxime. The reaction mass is neutralized with aqueous ammonia to a cmde caprolactam layer and a saturated solution of ammonium sulfate. Approximately 1.5 kg of the total 4.4 kg ammonium sulfate per kilogram of caprolactam is produced in this step. Purification is by multistage vacuum crystallization from aqueous solution in neatly quantitative yield. 

Toray. The photonitrosation of cyclohexane or PNC process results in the direct conversion of cyclohexane to cyclohexanone oxime hydrochloride by reaction with nitrosyl chloride in the presence of uv light (15) (see Photochemical technology). Beckmann rearrangement of the cyclohexanone oxime hydrochloride in oleum results in the evolution of HCl, which is recycled to form NOCl by reaction with nitrosylsulfuric acid. The latter is produced by conventional absorption of NO from ammonia oxidation in oleum. Neutralization of the rearrangement mass with ammonia yields 1.7 kg ammonium sulfate per kilogram of caprolactam. Purification is by vacuum distillation. The novel chemistry is as follows ... 

The conversion of cyclohexanone to cyclohexanone oxime is brought about by the use of hydroxylamine sulphate. The sulphuric acid is neutralised with ammonia to ammonium sulphate and this is separated from the oxime. In the presence of oleum the oxime undergoes the process known as the Beckmann rearrangement to yield the crude caprolactam. After further neutralisation with ammonia the caprolactam and further ammonium sulphate are separated by solvent extraction (Figure 18.7). 

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... 

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) ... 

Fe3+, La3+ and Ce3+ ion-exchanged MAPO-36 was prepared by wet ion-exchange method. The materials were characterized by XRD, TGA and TPD (ammonia). Lewis acid metal ions are suggested to remain as charge compensating MO+ species after calcination in ion-exchanged MAPO-36. Beckmann rearrangement of cyclohexanone oxime was studied over these catalysts in the vapour phase. 

Beckmann rearrangement of oxime is an acid catalysed reaction. The environmental problems associated with the use of sulphuric acid instigated interest to use number of solid acid catalysts [1], There are only scanty references about Lewis acid ion-exchanged MeAlPOs. Beyer et al. [2], Mihalyi et al. [3] and Mavrodinova et al. [4] already suggested the presence of Lewis acid metal ions as MO+ species in zeolites. The present study focussed the synthesis and characterisation of Fe3+, La3+ and Ce3+ ion-exchanged MAPO-36. The catalytic results of Beckmann rearrangement of cyclohexanone oxime over ion-exchanged catalysts are delineated in this article. 

Zeolites have also been described as efficient catalysts for acylation,11 for the preparation of acetals,12 and proved to be useful for acetal hydrolysis13 or intramolecular lactonization of hydroxyalkanoic acids,14 to name a few examples of their application. A number of isomerizations and skeletal rearrangements promoted by these porous materials have also been reported. From these, we can underline two important industrial processes such as the isomerization of xylenes,2 and the Beckmann rearrangement of cyclohexanone oxime to e-caprolactam,15 which is an intermediate for polyamide manufacture. Other applications include the conversion of n-butane to isobutane,16 Fries rearrangement of phenyl esters,17 or the rearrangement of epoxides to carbonyl compounds.18... 

The transformation of oximes to lactams (the Beckmann rearrangement) was one of the earliest such acid-catalyzed reactions to be reported with TS-1 (138) and TS-2 (247) catalysts. The rearrangement of cyclohexanone oxime to e-caprolactam proceeds with high selectivity in the presence of TS-1, with high catalyst stability (138,247). 

Caprolactam is discussed more completely in Chapter 11, Section 5. It is made from cyclohexane by oxidation to cyclohexanone-cyclohexanol mixture, formation of cyclohexanone oxime, and acid-catalyzed rearrangement. 

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. 

Organoaluminum-promoted Beckmann rearrangement/methylation of cyclohexanone oxime mesylate, followed by allylation of ketimine 40a and Mannich cyclization of the intermediate iminium-allylsilane, provides piperidine 40b possessing cxo-unsaturation (08BKC1669). 

The Beckmann rearrangement of cyclohexanone oxime catalysed by solid metaboric acid (286) has also been investigated (equation 94). When ketoximes, mixed with 286 (formed from boric acid at 100°C/0.1 Torr), are heated (140°C/7-42 h) the corresponding amides or lactams are produced in excellent yields (62-92%). Under the... 

To explain the difficulties encountered in the reuse of sulfonyl chloride functionalized ionic liquids during Beckmann rearrangement, Deng and colleagues proposed a mechanism for rearrangement of cyclohexanone oxime (equation 97). 

Diisobutylaluminium hydride may even be used to promote the rearrangement in O-unsubstituted oximes. Several heterocyclic fused azepines 475 were synthesized from the corresponding cyclohexanone oximes (equation 203). 

The classical production of e-caprolactam is based on cyclohexanone oxime and on its Beckmann rearrangement. For this step, aU manufacmrers use fuming sulfuric acid or oleum, sometimes enriched with more sulfur trioxide than present anyway in the oleum, to increase the rate of the rearrangement process. 

The rearrangement was done in similar ways by different caprolactam producers, and the differences can only be found in the purification processes. With the formation of ammonium sulfate being the most important problem for the producers of e-caprolactam, and due to the rising costs of its removal, many companies searched for new possibilities to produce caprolactam. There are some important industrial processes avoiding the cyclohexanone oxime as an intermediate product. 

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