Cyclohexyl reaction + cyclohexanone

Phenylnaphthalene has been prepared by the reaction of a-halonaphthalenes with mercury diphenyl3 6 or with benzene in the presence of aluminum chloride,6 and by means of the Gri-gnard synthesis, starting with either bromobenzene, cyclohexyl chloride, and a-tetralone 7 or with a-bromonaphthalene and cyclohexanone.6 8 9 Dehydrogenation of the reduced naphthalene has been accomplished by the use of sulfur,6 bromine,8 platinum black, or selenium.7 The formation of the hydrocar-... 

The recombination of the cyclohexyl peroxy radicals produced in one of these two reaction pathways gives rise to cyclohexanol, cyclohexanone and oxygen ( disproportionation ) ... 

The organosilane reduction of ketones in the presence of alcohols provides an excellent route to unsymmetrical ethers. The reaction of cyclohexanone with ethanol and Et3SiH/TFA gives cyclohexyl ethyl ether in good yield.327,328 The... 

The question about the competition between the homolytic and heterolytic catalytic decompositions of ROOH is strongly associated with the products of this decomposition. This can be exemplified by cyclohexyl hydroperoxide, whose decomposition affords cyclo-hexanol and cyclohexanone [5,6]. When decomposition is catalyzed by cobalt salts, cyclohex-anol prevails among the products ([alcohol] [ketone] > 1) because only homolysis of ROOH occurs under the action of the cobalt ions to form RO and R02 the first of them are mainly transformed into alcohol (in the reactions with RH and Co2+), and the second radicals are transformed into alcohol and ketone (ratio 1 1) due to the disproportionation (see Chapter 2). Heterolytic decomposition predominates in catalysis by chromium stearate (see above), and ketone prevails among the decomposition products (ratio [ketone] [alcohol] = 6 in the catalytic oxidation of cyclohexane at 393 K [81]). These ions, which can exist in more than two different oxidation states (chromium, vanadium, molybdenum), are prone to the heterolytic decomposition of ROOH, and this seems to be mutually related. 

Apart from the reaction of cyclohexanecarboxylic acid with methyllithium, cyclohexyl methyl ketone has been prepared by the reaction of cyclohexylmagnesium halides with acetyl chloride or acetic anhydride and by the reaction of methylmagnesium iodide with cyclohexanecarboxylic acid chloride. Other preparative methods include the aluminum chloride-catalyzed acetylation of cyclohexene in the presence of cyclohexane, the oxidation of cyclohexylmethylcarbinol, " the decarboxylation and rearrangement of the glycidic ester derived from cyclohexanone and M)utyl a-chloroj)ropionate, and the catalytic hydrogenation of 1-acetylcycIohexene. "... 

Chemical/Physical. The gas-phase reaction of cyclohexane with OH radicals in the presence of nitric oxide yielded cyclohexanone and cyclohexyl nitrate as the major products (Aschmann et al., 1997). 

Vanoppen et al. [88] have reported the gas-phase oxidation of zeolite-ad-sorbed cyclohexane to form cyclohexanone. The reaction rate was observed to increase in the order NaY < BaY < SrY < CaY. This was attributed to a Frei-type thermal oxidation process. The possibility that a free-radical chain process initiated by the intrazeolite formation of a peroxy radical, however, could not be completely excluded. On the other hand, liquid-phase auto-oxidation of cyclohexane, although still exhibiting the same rate effect (i.e., NaY < BaY < SrY < CaY), has been attributed to a homolytic peroxide decomposition mechanism [89]. Evidence for the homolytic peroxide decomposition mechanism was provided in part by the observation that the addition of cyclohexyl hydroperoxide dramatically enhanced the intrazeolite oxidation. In addition, decomposition of cyclohexyl hydroperoxide followed the same reactivity pattern (i.e., NaY < BaY... 

For the two aldehydes discussed in the previous section (R, R = H R = Me, R = Hep), the reaction is thermoneutral in the gas phase. Thermoneutrality would also be expected for ketones, but which ketone/oxime should be the standard for comparison In the gas phase there are two possibilities acetone/acetone oxime and cyclohexanone/cyclohexanone oxime. The latter pair may be assumed to be essentially strainless, or at least that their strain energies are very much the same. The assumption is borne out by substituting these two pairs into equation 23 (R, R = Me R R = — (CH2)5—) and finding that the enthalpy of reaction is only 1.2 kJ moE, essentially thermoneutral. Comparing the Cg species with the cyclohexyl species (RR = —(CH2)s- R /R = Me/Hex, Et/Pen, Pr/Bu), the enthalpies... 

Information concerning the chemistry of meso-ionic 3-alkyl- and 3-aryl-l,2,3,4-oxatriazol-5-ones (271) is limited, but further investigation may well be encouraged by reports of pronounced hypotensive activity. 3-Cyclohexyl-1,2,3,4-oxatriazol-5-one (271, R = cyclohexyl) is resistant to attack by dilute mineral acid, but warm concentrated sulfuric acid gives cyclohexanol and carbon dioxide. In contrast, acid hydrolysis of 3-phenyl-l,2,3,4-oxatriazol-5-one (271, R = Ph) yields phenyl azide. Meso-ionic 3-cyclohexyl-l,2,3,4-oxatriazol-5-one shows two unusual reactions its photoirradiation in benzene gives cyclohexanone and heating with diphenylacetylene )delds l-cyclohexyl-4,5-diphenyl-1,2,3-triazole (276) rather than the expected 2-cyclohexyl-4,5-diphenyl-1,2,3-triazole. 

The selective oxidation of saturated hydrocarbons is a reaction of high industrial importance. Besides a variety of other oxidants, hydrogen peroxide as a very clean oxidant has also been used for these purposes . As an example, in 1989 Moiseev and coworkers reported on the vanadium(V)-catalyzed oxidation of cyclohexane with hydrogen peroxide (Scheme 146) . When the reaction was carried out in acetic acid cyclohexanol and cyclohexanone were formed, bnt conversions were very poor and did not exceed 13%. Employing CF3COOH as solvent, complete conversions could be obtained within 5 min-ntes. Here, cyclohexyl trifluoroacetate was the main product (85% of the products formed) resulting from the reaction of cyclohexanol (the primary product of the oxidation) with CF3COOH. 

The oxidation of cyclohexane to cyclohexanone and cyclohexanol is an important industrial procedure used in the synthesis of adipic acid. Srinivas and Mukhopadhyay (1994) reported the oxidation of cyclohexane in sc C02, yielding cyclohexanone and cyclohexanol as the major reaction products. At the high temperatures employed in this study (>137°C), cyclohexyl hydroperoxide (c-C6HnOOH), which is produced by the mechanism outlined in Scheme 4.11, decomposes to cyclohexanone and cyclohexanol. 

Generally, the issue of whether a truly solid Cr catalyst has been created for the aforementioned reactions is unresolved. This point is illustrated most clearly by all the work that has been devoted, in vain, to Cr molecular sieves (55-57). Particularly the silicates Cr-silicalite-1 and Cr-sihcahte-2 and the aluminophosphate Cr-AlPO-5 have been investigated. These materials have been employed, among others, for alcohol oxidation with t-BuOOH, for allylic (aut)oxidation of olefins, for the autoxidation of ethylbenzene and cyclohexane, and even for the catalytic decomposition of cyclohexyl hydroperoxide to give mainly cyclohexanone ... 

One-electron Fe redox catalysts may also be immobilized by incorporation into aluminophosphate frameworks. Dugal el al. (143) reported the oxidation of cyclohexane to give adipic acid with air as the oxidant in the presence of Fe-AlPO-31. This molecular sieve has narrow pores, with a 0.54-nm diameter. Cyclohexane is easily adsorbed in the micropores, but desorption of initial products such as cyclohexyl hydroperoxide or cyclohexanone is slow. Consequently, subsequent radical reactions occur until the cyclohexyl ring is broken to form linear products that are sufficiently mobile to diffuse out of the molecular sieve ... 

In recent years increasing use has been made of an alternative procedure involving the oxidation of hydrocarbon substrates in polar solvents, usually acetic acid, in the presence of relatively large amounts of metal catalysts, usually the metal acetate. These reactions are characterized by high rates of oxidation, high conversions, and more complete oxidation of the substrate. For example, the classic autoxidation of cyclohexane is carried out to rather low conversions and affords mainly cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone. Autoxidation of cyclohexane in acetic acid, in the presence of substantial amounts of cobalt acetate catalyst, results in the selective formation of adipic acid at high conversions (see Section II.B.3.c). 

Once again, the best choice is a Grignard reaction, but there are two possible reactions that give the methylcyclohexane skeleton. A cyclohexyl Grignard reagent can add to formaldehyde, or a methyl Grignard reagent can add to cyclohexanone. (There are other possibilities, but none that are more direct.)... 

The first step, oxidation of cyclohexane to cyclohexanol and cyclohexanone, follows the general mechanism outlined by reactions 8.13 to 8.17. Trace quantities of cyclohexyl hydroperoxide 8.9 can initiate the radical chain, where the radicals 8.10 and 8.11 take part in the propagation steps. 

When cyclohexanone forms via a cyclohexyl radical, a similar sequence of reactions occurs at the carbon a to the carbonyl group affording 1,2-cyclohexanedione which is eventually cleaved to adipic acid. 

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