Cyclohexanone from phenol

An alternative to cyclohexanones from phenols involves ring saturation to the alcohol, followed by oxidation 14). 

The production of Cyclohexanone from phenol was simplified when selective hydrogenation with Pd catalysts was made possible ([see Eq. 21.3)]. In this process, phenol is completely converted in the gas phase at 140 to 170°C and 1 to 2 bar using a supported Pd catalyst containing alkaline earth oxides (e.g., Pd-CaO/A Os). The selectivity to Cyclohexanone is greater than 95%46. 

Hydrogen circulation pump 2 Phenol vaporizer 3 Reactor 4 Cyclohexanone separator Figure 5.22 Flow diagram for the production of cyclohexanone from phenol... 

The original preparation of cyclohexanone from phenol by hydrogenation to cyclohexanol followed by dehydrogenation has since been improved. Selective hydrogenation of phenol to cyclohexanone is possible using a palladium catalyst at 140°-170°C and 1-2 atm. An AlliedA ickers-Zimmer catalyst contained 0.5-5% palladium, supported on a low-surface-area calciiun aluminate which contained about 8-9% calcium oxide. ... 

Reductive amination of cyclohexanone using primary and secondary aHphatic amines provides A/-alkylated cyclohexylamines. Dehydration to imine for the primary amines, to endocycHc enamine for the secondary amines is usually performed in situ prior to hydrogenation in batch processing. Alternatively, reduction of the /V-a1ky1ani1ines may be performed, as for /V,/V-dimethy1 cyclohexyl amine from /V, /V- di m e th y1 a n i1 i n e [121 -69-7] (12,13). One-step routes from phenol and the alkylamine (14) have also been practiced. 

Christopher and Fox have given examples of the way in which polycarbonate resins may be tailor-made to suit specific requirements. Whereas the bis-phenol from o-cresol and acetone (bis-phenol C) yields a polymer of high hydrolytic stability and low transition temperature, the polymer from phenol and cyclohexanone has average hydrolytic stability but a high heat distortion temperature. By using a condensate of o-cresol and cyclohexanone a polymer may be obtained with both hydrolytic stability and a high heat distortion temperature. 

About half of the nylon made in the world is made from the polymerization of caprolactam. Although the cyclohexanone needed to make caprolactam can be made from cyclohexane as shown above, most of it is made from phenol. 

The reaction product was filtered to remove catalyst and analyzed in GC equipped with an HP5 (30 m X 0.32 mm X 0.25 pm) column. The temperature program used for analysis (31 °C - 35 min - 1 °C/min - 40 °C - 10 °C/min -120 °C) ensured complete separation of the cyclohexanol, cyclohexanone, and phenol peaks. The conversion and selectivity were calculated directly from the area of each peak. 

Oxidation of organic compounds by dioxygen is a phenomenon of exceptional importance in nature, technology, and life. The liquid-phase oxidation of hydrocarbons forms the basis of several efficient technological synthetic processes such as the production of phenol via cumene oxidation, cyclohexanone from cyclohexane, styrene oxide from ethylbenzene, etc. The intensive development of oxidative petrochemical processes was observed in 1950-1970. Free radicals participate in the oxidation of organic compounds. Oxidation occurs very often as a chain reaction. Hydroperoxides are formed as intermediates and accelerate oxidation. The chemistry of the liquid-phase oxidation of organic compounds is closely interwoven with free radical chemistry, chemistry of peroxides, kinetics of chain reactions, and polymer chemistry. 

The common name caprolactam comes from the original name for the Ce carboxylic acid, caproic acid. Caprolactam is the cyclic amide (lactam) of 6-aminocaproic acid. Its manufacture is from cyclohexanone, made usually from cyclohexane (58%), but also available from phenol (42%). Some of the cyclohexanol in cyclohexanone/cyclohexanol mixtures can be converted to cyclohexanone by a ZnO catalyst at 400°C. Then the cyclohexanone is converted into the oxime with hydroxylamine. The oxime undergoes a very famous acid-catalyzed reaction called the Beckmann rearrangement to give caprolactam. Sulfuric acid at 100-120°C is common but phosphoric acid is also used, since after treatment with ammonia the by-product becomes... 

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. 

Kennedy and Stock reported the first use of Oxone for many common oxidation reactions such as formation of benzoic acid from toluene and of benzaldehyde, of ben-zophenone from diphenyhnethane, of frawi-cyclohexanediol Ifom cyclohexene, of acetone from 2-propanol, of hydroquinone from phenol, of e-caprolactone from cyclohexanone, of pyrocatechol from salicylaldehyde, of p-dinitrosobenzene from p-phenylenediamine, of phenylacetic acid from 2-phenethylamine, of dodecylsulfonic acid from dodecyl mercaptan, of diphenyl sulfone from diphenyl sulfide, of triphenylphosphine oxide from triphenylphosphine, of iodoxy benzene from iodobenzene, of benzyl chloride from toluene using NaCl and Oxone and bromination of 2-octene using KBr and Oxone . Thus, they... 

The separation section receives liquid streams from both reactors. For assessment the residue curve map in Figure 5.7 is of help. The first separation step is the removal of lights. This operation can take place in a distillation column operated under vacuum (200mmHg) with a partial condenser. Next, the separation of the ternary mixture cyclohexanone/cyclohexanol/phenol follows. Two columns are necessary. In a direct sequence (Figure 5.15) both cyclohexanone and cyclohexanol are separated as top products. The azeotrope phenol/cyclohexanol to be recycled is the bottoms from the second split In an indirect sequence (Figure 5.16) the azeotropic phenol mixture is a bottom product already from the first split. Then, in the second split cyclohexanone is obtained as the top distillate, while cyclohexanol is taken off as the bottom product The final column separates the phenol from the heavies. 

Ketones arise from phenols by isomerization of unsaturated alcohols (37). Palladium is the most suited for this type of reaction because of its high isomerization activity coupled with a very low rate of reduction of the resulting ketones (6). Excellent yields of ketones often may be obtained rhodium will give at times quite substantial yields of cyclohexanones (50-65% methylcyclohexanones from cresols) (38), but in other reductions such as resorcinol, little ketone accumulates over either rhodium or platinum under conditions where it is a major product over palladium (29). 

A liquid mixture of cyclohexanone(l)/phenol(2) for which x, = 0.6 is in equilibrium with its vapor at 144°C. Determine the equilibrium pressure P and vapor composition y, from the following information ... 

Caprolactam can be made by the Beckmann rearrangement of the oxime f of cyclohexanone. (Check that you can draw the mechanisms, of both these reactions and look at Chapters 14 and 37 if you find you can t.) Cyclohexanone used to be made by the oxidation of cyclohexane with molecular oxygen until the explosion at Fiixborough in Lincolnshire on 1 June 1974 that killed 28 people. Now cyclohexanone is made from phenol. 

Fig. 2.28. Flow diagram for cyclohexanone production from phenol.

Zeolites have been used as (acid) catalysts in hydration/dehydration reactions. A pertinent example is the Asahi process for the hydration of cyclohexene to cyclo-hexanol over a high silica (Si/Al>20), H-ZSM-5 type catalyst [57]. This process has been operated successfully on a 60000 tpa scale since 1990, although many problems still remain [57] mainly due to catalyst deactivation. The hydration of cyclohexanene is a key step in an alternative route to cyclohexanone (and phenol) from benzene (see Fig. 2.19). The conventional route involves hydrogenation to cyclohexane followed by autoxidation to a mixture of cyclohexanol and... 

Molecular oxygen can also oxidize a variety of organic compounds, including hydrocarbons, aldehydes, amines, ethers and ketones. These autooxidation reactions can be used to make a variety of small molecules and a number of industrial processes rely on the controlled oxidation of organics using molecular oxygen (often with a metal catalyst). Examples include the formation of phenol and acetone from cumene (isopropylbenzene) and cyclohexanone from cyclohexane. Phenol is a popular starting material for a number... 

Figure 1. Diagrammatic representation of olfactory receptor cell activity during odour stimulation. The spot size is roughly proportional to spike frequency (spike/min). Receptor cells taken at random from the epithelium of a frog are identified hy a serial number in the left column (60 in all). ACE - acetophenone, ANI - anisole, BUT - n-butanol, CAM - DL-camphor, CDN - cyclodecanone, CIN - cineole, CYM, p-cymene, DCT D-citronellol, HEP - n-heptanol, ISO - isoamylacetate, IVA - isovaleric acid, LIM -D-linonene, MAC - methyl-amylketone, MEN - L-menthol, PHE - phenol, PHO -thiophenol, PYR - pyridine, THY - thymol, XOL - cyclohexanol, XON - cyclohexanone. (From Sicard Holley [7]).

Although outside the scope of the present chapter, another transformation of interest is the conversion of the fully hydrogenated product from phenol, namely cyclohexanol, to cyclohexanone in 100% yield by addition of a dichloromethane solution to bis(quinuclidine)bromine fluoroborate and silver fluoroborate in dichloromethane followed by reaction for 30 mins.at ambient temperature (ref.65). 

Polyamides. The first commercially produced synthetic polyamides were made from dibasic acids and diamines exemplified by polyhexameth-ylene adipamide (6,6-nylon). Adipic acid was first commercially produced by osdation of cyclohexanone produced from phenol, but today it is largely produced by oxidation of cyclohexane derived from either benzene or petroleum. Sebacic acid, another important nylon intermediate, is produced by caustic oxidation of ricinoleic acid from castor oil. 

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