Cyclohexanone production

Estimated aimual cyclohexanone production capacities are shown in Table 3 the production is greater than 90% captive for caprolactam production (13). The aimual cyclohexanol production is only 10 thousand metric tons. These production figures do not include KA-od (cyclohexanol-cyclohexanone) production for adipic acid. Worldwide annual capacity for cyclohexanone is approximately 3.0 million metric tons, also primarily for caprolactam production. Projected new capacity for caprolactam could add 0.5 million metric tons worldwide in this decade. 

Solvolyses of these cyclic vinyl triflates at 100 in 50% aqueous ethanol, buffered with triethylamine, lead exclusively to the corresponding cyclo-alkanones. Treatment of 176 with buffered CH3COOD gave a mixture of cyclohexanone (85%) and 1-cyclohexenyl acetate (15%). Mass spectral analysis of this cyclohexanone product showed that the amount of deuterium incorporation was identical to that amount observed when cyclohexanone was treated with CH3COOD under the same conditions. This result rules out an addition-elimination mechanism, at least in the case of 174, and since concerted elimination is highly unlikely in small ring systems, it suggests a unimolecular ionization and formation of a vinyl cation intermediate in the solvolysis of cyclic triflates (170). The observed solvent m values, 174 m =. 64 175 m =. 66 and 16 m =. 16, are in accord with a unimolecular solvolysis. 

H2C)5C0 = Cyclohexanone product isolated after acid hydrolysis as an o, /6-unsaturated carbonyl compound. 

Estimated annual cyclohexanone production capacities were 665x Iff1 t in 1992 the production is greater than 90% captive for caprolactam production. The annual cyclohexanol production is only 10 thousand... 

A study on the reduction of aliphatic ketones, which contributed to understanding the mechanism and provided some examples of synthetic interest, has been in progress in our laboratory. It has involved the reduction of aliphatic ketones in organic solvents with (C4H9)4NBF4 as the electrolyte and dimethylpyrrolidinium (DMP+) in small concentrations as the catalyst. Most of the substrates listed below do not exhibit reduction waves or peaks in the potential window . The reduction of all the substrates can be catalyzed by DMP+ and in the presence of the catalyst preparative reductions could be carried out at potentials at which the substrates are otherwise electroinactive. Catalysis was also ascertained with CV and polarographic measurements like those described in the introduction for cyclohexanone. Product analysis... 

Ce4+ is easily exchanged on resins such as Nation. Ce-Nafion catalyzed the oxidation of carveol to carvone with t-BuOOH as the oxidant no data characterizing leaching were provided (59). CeC>2 on AI2O3 was used as a solid catalyst for the cooxidation of cyclohexane and cyclohexanone. Products are dibasic acids and e-caprolactone. It was claimed that in water-free reaction conditions, Ce is not eluted from the solid (342). 

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

Irradiation of oxaziridine 24 in the presence of benzophenone, a classic triplet sensitizer, underwent reaction by two pathways to give a mixture of amide 25 and cyclohexanone products <1995JA7812>. It was proposed that ketyl radicals 26 are involved in the triplet sensitization chemistry of the oxaziridine and a mechanism was proposed as shown in Scheme 1. 

When Br is substituted for I, the cyclohexanone product can be isolated in predominance only when HMPT is the solvent. If the methylene chain is lenghened by one unit, the cyanohexane and unreacted starting material are the major products. Only 2% of a cycloheptanone is isolated. 

Richter and Vogel oxidized cyclohexane in supercritical water for a varying reaction time from 5 to 80 sec range. The partial oxidation resulted in the desired cyclohexanone product, but the yield was very low (Fig. 7). The by-products included carboxylic acids, carbon monoxide, and carbon dioxide. 

We prepared composite catalysts containing Ru in Ti silicalite (molar composition Si02 0.025TiO2 0.001 Ru). The catalyst was suspended in 3 mL of a mixture (1 4 weight ratio) of cyclohexanol and cyclohexane in a 100 mL steel autoclave and stirred imder oxygen at 150 for 24 hours. Cyclohexane was converted to cyclohexanone to an extent of 15 - 20%. The reaction was highly selective for cyclohexanone. Products other than unreacted cyclohexane and cyclohexanol were not observed. More than the calculated amount of oxygen was consumed. The experimental set up was similar to the one described by Clerici... 

Fig. 1211. Cyclohexanone production from cyclohexane. Dehydrogenation of cydohexanol/cyciohexanone mixture.

Given the reaction sequence, give a mechanistic rationale for formation of the cyclohexanone product OH 1. KH, THF/HMPA... 

Interestingly, pyrrolidine provided access to the cyclohexanone products in good yield (70%) and moderate exo.endo selectivities (6 1). The exo product was conjectured to form preferentially due to more favourable iminium ion solvation and hydrophobic interactions in the transition state, compared to the standard secondary orbital interactions contributing to endo selectivity. Other ketones could undergo self-Diels-Alder formation ... 

Purpose, The oxidation of a secondary alcohol to a ketone is explored using the hypochlorite reagent. Steam distillation is used to separate the product from the reaction mixture and chromatographic techniques are used to purify and isolate the cyclohexanone product. 

In this experiment, a Hickman still is used to isolate the crude cyclohexanone product from the reaction mixture in an example of the steam distillation technique (see Prior Reading). The crude mixture collected in the collar of the still consists of cyclohexanone, water, and acetic acid. If any unreacted cyclohexanol is present in this mixture, it is removed in the subsequent chromatographic purification sequence using alumina. Gas chromatographic analysis may be used to determine the purity of the cyclohexanone product. 

Use a Pasteur filter pipet to separate the ether layer containing the cyclohexanone product from the aqueous phase and transfer it to a microscale drying and chromatography column. Assemble the column using a Pasteur filter pipet packed first with about 50 mg of sand, then with 300 mg of alumina (Activity I, see Glossary), followed by 200 mg of anhydrous magnesium sulfate (- ). Wet the column with diethyl ether before the transfer. 

The purity of the cyclohexanone product may be determined using gas chromatographic analysis (see Prior Reading and Pxperiment [5A] to review this technique and the experimental conditions for its use). Determine the boiling point and density of your product compare your results to those given in the literature. 

In the isolation of the cyclohexanone product, 50 mg of sodium chloride is added to the water-cyclohexanone-... 

In 1967, the ammonium sulfate plant had been converted to production of caprolactam, a product used to make nylon. A second plant on the site was completed in 1972, increasing the original 20,000 tons/year capacity to 70,000 tons/year, crowding an already congested plant. The plant control room was located near the cyclohexanone production facilities. Caprolactam is based on the oxidation of cyclohexane to cyclohexanone, a highly exothermic reaction at 8.8 kg/cm (126 psig) and 155°C (311°F). 

Multifunctional bicyclic cyclohexenone and cyclohexanone products were obtained in good yields with good tolerance of various functional groups and different tethers. Interestingly, for 1-yne-VCPs having an internal alkyne, a competing formal [5+l]/[2+2+l] process arose tmder some conditions (Scheme 10b)... 

Originally, all cyclohexanone production through the selective oxidation of cyclohexane was carried out via catalysed processes. In most cases, such as the processes of BASF, DSM and Zaklady Azotowe Tamow (Cyclopol process), sol-... 

The selectivity observed in the intramolecular aldol reaction of hexane-2,5-dione is due to the fact that all steps in the mechanism are readily reversible, so an equilibrium is reached. Thus, the relatively strain-free cyclopentenone product is considerably more stable than the highly strained cyclopropene alternative. For similar reasons, intramolecular aldol reactions of 1,5-diketones lead only to cyclohexanone products rather than to acyl cyclohutenes. 

Harrity exploited the carbocation stabilizing ability of cobalt-alkyne complexes to promote a novel O C rearrangement reaction. Exposure of cyclic enol ether 23 to diethylaluminum chloride promotes ionization of the C-O bond to yield the stabilized carbocation and an enolate. Bond rotation followed by C-C bond formation provides cyclohexanone product 24. ... 

---