Cyclohexanone oxime preparation

Reaction of hydroxylamine-0-sulfonic acid with cyclohexanone in alkaline solution can be shown to give pentamethyleneoxazirane (16). Compound 16 is an isomer of cyclohexanone oxime. It decomposes even at room temperature and thus cannot be prepared in a pure state. 

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. 

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... 

PREPARATION OF 2-PROPYL-l-AZACYCLOHEPTANE FROM CYCLOHEXANONE OXIME (IH-Azeplne, hexahydro-2-propyI-, (t))... 

Nitroalkanes. A process was developed and operated for a time for the manufacture of s-caprolactam based on the nitration of cyclohexane.197 Nitrocyclohexane thus prepared was transformed to e-caprolactam via cyclohexanone oxime. At present the only industrial process to produce nitroalkanes by direct nitration is the manufacture of nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane. 

The starting oximes (acetophenone oxime and cyclohexanone oxime) were prepared by reaction of the corresponding carbonyl compound with hydroxylamine hydrochloride. The purity of the resulting oximes was checked by GC and IR spectroscopy after recrystallisation of the samples. 

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) ... 

The reaction was carried out at 200-220°C in a rotating autoclave for 8 hr. Maximum pressure developed in the course of synthesis is 27 atm. Under these conditions, when acetylene instead of CaC2 is used, the yield of pyridines grows to 20-30% (80KGS1299 84MI1). Thus, from cyclohexanone oxime 6-methyl-l,2,3,4,6,8,9,10-octahydrophenanthridine (106) can be prepared. 

Tetrahydroindoles (1, 2) are prepared by the condensation of cyclohexanone oxime (116) with vinyl chloride in the presence of KOH in a DMSO medium at 90-140°C under atmospheric pressure (Scheme 56) (81MIP1 86ZOR489). 

Tetrahydroindole (1) was isolated by extraction of the reaction mixture with organic solvents (Et20, benzene) and purified by distillation or recrystallization. This process for preparing 4,5,6,7-tetrahydroindole is simple enough, industrially feasible, safe, and based on the cheap and accessible raw materials. Cyclohexanone oxime is an inexpensive large-scale commercial product (caprolactam synthesis intermediate), vinyl chloride being one of the cheapest commercial vinyl compounds. 

An example of the simplicity and potential of the photo-oxygenation reaction is described for the preparation of (Z)-l-hydroperoxy-A-[(Z)-3-methoxycarbonyl)-2-propenylidene]cyclohexylamine A-oxide (P) starting from 2-methoxyfuran and cyclohexanone oxime, which both can be purchased and used without further purification. 

O-Methylcaprolactim has been prepared by the reaction of cyclohexanone oxime, p-toluenesulfonyl chloride, and methanol 3 and by the procedure described above, which is a modification of the method given in the patent literature.4... 

On successive treatment with trimethyloxonium tetrafluoroborate, triethylamine and aqueous acid, oxime acetate 83 prepared from cyclohexanone oxime and Ac20 yields a-acetoxy ketone 87 (Scheme 7). A similar result is obtained with other symmetric ketones including 4-heptanone, deoxybenzoin and dibenzyl ketone. 87 can also be formed by the reaction of cyclohexanone and O-acetyl-Af-methylhydroxylamine hydrochloride upon hydrolysis. If the reaction time is prolonged prior to hydrolysis, ketoamide 89 is isolated as the main product. The key step of the reaction is the [l,3]-acetoxy shift of 7V-acetoxyenamine 85 to the a-acetoxyimine 86. The formation of 89 provides support for the intermediacy of acetoxyimine 86 in the reaction sequence. The evidence available suggests that the [l,3]-acetoxy migration proceeds via a Claisen-type rearrangement (Scheme 7)78. 

Various procedures have been developed for the production of oximes from nitroparaffins. Direct reduction with zinc dust and acetic acid has been proposed, but the yields are poor because of the simultaneous formation of amines. A synthesis for cyclohexanone oxime has been demonstrated which involves the formation and selective hydrogenation of 1-chloro-l-nitrocyclohexane. The halogenated intermediate is prepared in quantitative yield by chlorination of the sodium salt of acz -nitrocyclo-hexane, and subsequent hydrogenation is performed in an 80% yield over palladium-on-charcoal, ... 

The reaction is reversible, but the state of equilibrium highly favors the desired products. Preparations of large quantities for synthetic work are illustrated for methyl ethyl ketoxime, cyclohexanone oxime, hept-aldoxime, and benzophenone oxime, the procedures varying somewhat with the nature of the carbonyl compound. In some instances, a readily available and cheap reagent like sodium hydroxylamine disulfonate, HON(SO,Na)j, is first prepared from sodium nitrite and sodium bisulfite and, without isolation, treated with the carbonyl compound, Hydioxylamine-O sulfonic add, Ii,NOSO,H, is still another reagent and, like sodium hydroxylamine disulfonate, is used in the absence of a base. The preparation of hydroxylamine hydrochloride is described. ... 

Low-valent metal salts have been used to bring about reductive cleavage of oximes. Corey and Rich-man used chromium(II) acetate to convert O-acetyl ketoximes into imines, which were hydrolyzed to ketones. " Aqueous titanium(III) chloride and vanadium(II) salts also reduce oximes again, the imines are usually hydrolyzed in situ, but some hindered imines, such as compound (37), are isolable." A method of preventing hydrolysis is to carry out the reduction in anhydrous conditions in the presence of an acylating agent. The products of such reactions, when applied to oximes of enolizable ketones, are en-amides. For example, these ketoximes are converted into A/-formylenamines when heated in acetonitrile with anhydrous titanium(III) acetate and acetic formic anhydride cyclohexanone oxime gives the en-amide (38 97% Scheme 22)." This type of reduction has been used by Barton and coworkers to prepare enamides from steroidal oximes. They reported that the reaction could be performed by acetic... 

An e-caprolactam-tin(IV) chloride complex was prepared in nearly quantitative yield from the cyclohexanone oxime-tin(IV) chloride complex in the presence of sulfur trioxide and DBU in 1,2-dichloroethane at 60°C (74USP3828028). 

A simple oxide catalyst can be used in either the bulk state or supported on an inert oxide support material. The bulk oxides are usually prepared using a precipitation-calcination sequence similar to those described in Chapter 9 for the preparation of support oxides. " In general, the simple semiconductor oxides are not very good catalysts for synthetic reactions. The insulator oxides, however, can be used as solid acids and bases for a number of reactions. Alumina has been used as an acid catalyst for the vapor phase rearrangement of cyclohexanone oxime to caprolactam (Eqn. 10.9). Modification of the y-alumina surface by the addition of 10-20% of B2O3 increased its activity for this reaction, giving caprolactam in 80% selectivity even after several hours of continuous operation. "... 

Titanium (TS-1), niobium (NbS-1), and tantalum silicalite-1 (TaS-1) with MFI structure were synthesized by microwave heating of the TPAOH impregnated xerogels which were prepared by sol-gel process. Highly crystalline products were obtained in 30 min to 2 h with yields over 90%. The metallosilicates showed high catalytic performances in Beckmann recirrangement of cyclohexanone oxime to caprolactam. 

The structure of bis-ethylmethylglyoximatonickel(ii) has been redetermined. The complex is square-planar and the bond lengths in the ligands indicate considerable delocalization. The oxime complexes [Ni(aox)Cl2] and [Ni(cy)3Cl2] (aox = acetaldoxime cy = cyclohexanone oxime) have been prepared and both are octahedral. [Ni(HPPK)3](N03)2 [HPPK = syn-PhC(NOH)CjH N] has also been prepared. ... 

The second TS-1 based process which is likely to go into commercial production is the synthesis of cyclohexanone oxime from cyclohexanone, ammonia, and hydrogen peroxide (Roiiia et al., 1990) (reaction 6.13), which is the first step in the preparation of e-caprolactam (Montedipe, pilot plant). Oxime selectivity is >98% at a conversion of 99.9%. 

The most common starting materials for preparations of caprolactam are phenol, cyclohexane, and toluene. Some caprolactam is also made from aniline. In these synthetic processes, the key material is cyclohexanone oxime. The route based on phenol can be shown as follows ... 

Caprolactam Technologies Comparison. The ammoximation process simplifies a very complex part of the current CPL technology, namely the requirement of different hydroxylamine compounds for the cyclohexanone oxime synthesis. It is in Aese two steps, preparation of the hydroxylamine derivative and cyclohexanone oxime synthesis, that most of the undesired byproducts (NO SOj and ammonium sulfate) are formed. 

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