Beckmann rearrangment

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. 

When treated with certain reagents, the ketoximes in particular undergo the Beckmann rearrangement to isomeric acid amides (p. 227). 

Beckmann Rearrangement. Prepare the 85% sulphuric acid by adding 50 ml. of the concentrated acid cautiously to 10 ml. of water, stirring the mixture meanwhile, and then cool the diluted acid in ice-water. Place 16 ml. of the cold acid in a 500 ml. beaker, add 8 g, of the pure oxime, and warm the mixture cautiously until effervescence begins, and then at once remove the heat. A vigorous reaction occurs, and is soon complete. Repeat this operation with another 8 g. of the oxime in a second beaker the reaction is too vigorous to be carried out with larger quantities. 

By treatment of this oxime with phosphorus pentachloride or thionyl fhloride in ether solution, smooth conversion into benzanilide, m.p. 163°, results. The change of any oxime into a substituted amide under the conditions mentioned is usually termed the Beckmann rearrangement. The above example may be represented ... 

Beckmann rearrangement of benzophenone oxime to benz-anilide. Dissolve 2 g. of benzophenone oxime in 20 ml. of anhydrous ether in a small conical flask and add 3 g. of powdered phosphorus pentachloride (or 3 ml. of pure tbionyl chloride). Distil off the solvent and other volatile products on a water bath CAUTION ether), add 25 ml. of water, boil for several minutes and break up any lumps which may be formed. Decant the supernatant liquid, and recrystallise, in the same vessel, from boiling alcohol. The product is benzanilide, m.p. 163° confirm this by a mixed m.p. determination with an authentic specimen. 

The oximes of ketones undergo the Beckmann rearrangement on treatment with phosphorus pentachloride (118). 

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... 

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. 

The oxime is converted to caprolactam by Beckmann rearrangement neutralization with ammonia gives ca 1.8 kg ammonium sulfate per kilogram of caprolactam. Purification is by vacuum distillation. A no-sulfate, extraction process has been described, but incineration of the ammonium bisulfate recovers only sulfur values and it is not practiced commercially (14). 

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 course of the reaction is dependent on the configuration of the oxime. The (Z)-oxime gave 1,2-benzisoxazoles as the primary product while the (E)-oxime generally produced a Beckmann rearrangement product with or without subsequent cyclization to a benzisoxazole (Scheme 167) (67AHC(8)277). Bunnett conducted a kinetic study on the reaction shown in Scheme 167 and determined that cyclization to intermediate (551) was the rate determining step (61JA3805). 

BAY 94337 — see l,2,4rTriazin-5-one, 4-amino-6-t-butyl-3-methylthio- Bay region epoxides, 7, 189 Beckmann rearrangement, 7, 34 Beirut reaction, 3, 181-184 6, 407, 425 Bemegride... 

Beckmann rearrangement, 4, 292 pyrolysis, 4, 202 synthesis, 4, 223 Wittig reaction, 4, 294 Wolff-Kishner reduction, 4, 291 Indole, 1-acyl-2,3-disubstituted photoisomerization, 4, 204 photo-Fries rearrangement, 4, 204 photoisomerization, 4, 42 synthesis, 4, 82 Indole, 2-acyl acidity, 4, 297 synthesis, 4, 337, 360 Indole, 3-acyl-acidity, 4, 297 cleavage, 4, 289 reduction, 4, 289 synthesis, 4, 360 Indole, 7-acyl-synthesis, 4, 246... 

H-Indole, 3,3-dichloro-synthesis, 4, 369 3H-Indole, 3,3-dimethyl-synthesis, 4, 224 3H-Indole, 3-hydroperoxy-autoxidation, 4, 247 rearrangement, 4, 249 3H-Indole, 3-oximino-synthesis, 4, 209, 210 3H-Indole, 3-oximino-2-phenyl Beckmann rearrangement, 4, 210 Indoleacetic acid synthesis, 4, 337 Indole-3-acetic acid as growth regulator, 4, 372 synthesis, 4, 346 Indole alkaloids, 4, 373 synthesis, 4, 276... 

Beckmann rearrangement, 6, 156 Isothiazole, 3-alkoxy-tautomerism, 6, 145 Isothiazole, alkyl-bromination, 5, 58 Isothiazole, 3-alkyl-5-amino-synthesis, 6, 166 Isothiazole, alkylthio-mass spectra, 6, 142 Isothiazole, amino-azo dyes from, 1, 330 tautomerism, 6, 157 Isothiazole, 3-amino-synthesis, 5, 135 tautomerism, 6, 146 Isothiazole, 4-amino-azo dyes from, 6, 175 diazotization, 6, 158 methylation, 5, 95 quaternization, 6, 158 reactions... 

Beckmann rearrangement, 3, 710 Pyran-4-carbaldehyde, 2,2-dimethyl-tetrahydro-Reformatsky reaction, 3, 732 4H-Pyran-4-carbaldehydes synthesis, 3, 760-761 Pyran-2-carbonitrile, 5,6-dihydro-reactions, 3, 732... 

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