Oxidation, of cyclohexanone

The product (6 hexanohde) is a cyclic ester or lactone (Section 19 15) Like the Baeyer-Vilhger oxidation an oxygen atom is inserted between the carbonyl group and a carbon attached to it But peroxy acids are not involved m any way the oxidation of cyclohexanone is catalyzed by an enzyme called cyclohexanone monooxygenase with the aid of certain coenzymes... 

Selenium dioxide may be used for the oxidation of reactive methylene groups to carbonyl groups. An example is the oxidation of cyclohexanone to cyclohexane-1,2-dione (27). In the procedure, the reaction is carried out on camphor to give camphor... 

Littler has studied the oxidation of cyclohexanone with lead(IV), thallium(III), and mercury(II) salts (84), and found that, with all three reagents the rates of oxidation are independent of the concentration of oxidant. Oxidation by thallium(III) and mercury(II) in 35% aqueous perchloric acid showed first-order dependence on [H" ], and Littler suggested that the results were best interpreted in terms of the reaction sequence shown in Scheme 27. The major product of thallium(III) oxidation of... 

FIGURE 1 Continuous process for the manufacture of e-caprolactone by oxidation of cyclohexanone with peracetic acid. 

The chromic acid oxidation of cyclohexanone to adipic acid via 2-hydroxy-cyclohexanone and cyclohexane-l,2-dione is third order , viz. 

A few kinetic measurements on the acid permanganate oxidation of cyclohexanone have been reported by Littler . The reaction is first order in ketone but the order in oxidant was not clearly established. 

Kemp and Waters also found the oxidations of cyclohexanone and of mandelic, malonic and a-hydroxyisobutyric acids by Cr(VI) to be Mn(II)-catalysed. In these cases, as with oxalic acid, the [Cr(VI)] versus time plots are almost linear and the reaction becomes first order in substrate (or involves Michaelis-Menten kinetics), and, except at lowest catalyst concentrations, approximately first order in [Mn(II)]. Detailed examination of the initial rate of oxidation of a-hydroxyrobutyric acid as a function of oxidant concentration revealed, however, that the dependence is... 

Oxidation of cyclohexanone by thallic perchlorate has similar kinetics but includes an acidity dependence of the form (at 25°C, n = 1.3 M)... 

Preliminary results on the anaerobic oxidation of cyclohexanone by IrCle suggest that, although enolisation is rate-determining at pH 3 (when the oxidation rate is equivalent to the enolisation rate and the reaction is zero-order in oxidant but first order in acidity), the subsequent reaction of the radical is one of ligand-capture , viz. 

The coupling product is considered to involve a radical intermediate formed by one-electron oxidation, probably effected by Cr(IV). Similarly, the oxidation of cyclohexanone involves 2-hydroxycylohexanone and 1,2-cyclohexanedione as intermediates.208... 

FIGURE 14.1 Oxidation of cyclohexanone kinetic curves of 1-naphtol decay (curves without primes) and hydroperoxide formation (curves with primes) at T — 413K(1, l ),403K(2, 2 ), and 393 K (3, 3 ). 

An a-cleavage with subsequent [1,21-hydrogen shifts was observed in the electrochemical oxidation of cyclohexanone (Eq. 7) [84]. 

Industry, in fact, has a major interest in these diesters as building blocks for nylon 6,6 and nylon 7,7 in the production of polyesters and polyamides. However, their present synthesis raises an environmental concern. For instance, the oxidation of cyclohexanone by nitric acid (for the preparation of adipic acid), accounts for more than 10% of the total yearly release of N2O, which is among the main gases responsible for the greenhouse effect. The reaction of Scheme 4.14 represents an eco-friendly alternative synthesis of a,(i)-diesters which uses green reagents and, relevantly, has a 100% atom economy. The overall process is mechanistically described as a retro-Claisen condensation. 

Cyclohexanedione has been prepared by hydrolysis and decarboxylation of 2,5-dicarbethoxy-l,4-cyclohexanedione by using concentrated sulfuric acid, aqueous alcoholic phosphoric acid, or water at 195-200°, and by peroxyvanadic acid oxidation of cyclohexanone. 

The oxidation of cyclohexanone involves 2-hydroxycyclohexanone and 1,2-cyclo-hexanedione as intermediates.171... 

The process starts from tricyclohexylidene triperoxide which is obtained by oxidation of cyclohexanone with hydrogen peroxide. Pyrolysis leads to a mixture of 1,16-hexadecanolide and cyclopentadecane. The latter is oxidized by oxygen under boric acid catalysis to cyclopentadecanol which is subsequently oxidized to cyclopentadecanone [124,124a]. 

The Baeyer-Villiger oxidation of cyclohexanone to form e-caprolactone (78) using peroxybenzoic acid, as indicated in equation (40), may be considered as a further type of intramolecular displacement reaction of value in seven-membered ring synthesis (49JA2571). 

Metal oxides have often been used as catalysts for the autoxidation of hydrocarbons.1 In many cases the metal probably dissolves in the reaction medium and catalysis involves homogeneous metal complexes. However, according to a recent report56 cerium oxide catalyzes the liquid phase oxidation of cyclohexanone in acetic acid (5-15 bar and 98-118°C) without dissolving in the reaction medium. 

Our data on the catalyzed oxidation of cyclohexanone are shown in Tables I, II, and III. The solvent effects on adipic acid yield require comment. Although solvent effects often are considered to be small in free-radical chemistry, we find that our data is consistent with the published solvent effects on the decomposition rate of benzoyl... 

Table I. Solvent Effects in the Oxidation of Cyclohexanone to Adipic Acid (Reaction Conditions Cyclohexanone, 5 mL ...

Rh6(CO)16, the product mixture contains -caprolactone. Analysis of the oxidation products for the uncatalyzed and Rh6(CO)16-catalyzed oxidation of cyclohexanone shows the respective rations of -caprolactone to be 0.43 and 1.00 when measured against an added aliquot of dodecane. Thus there is a decrease in -caprolactone formation in the presence of Rh6(CO)16. This observation is consistent with the premise that the metal carbonyl accelerates the decomposition of peroxides. In the presence of Rh6(CO)16, the increased decomposition rate of peracid leading to a lower steady-state concentration of this species, and hence to its reduced transformation to -caprolactone is expected. These data support a reaction pathway proceeding via hydroperoxide and its sub-... 

A mixed Ni(n) and Fe(n) form of Dowex 50W catalyzes the oxidation of cyclohexanone with molecular oxygen in the presence of benzaldehyde to e-caprolactone <2000JCM196>. Chiral nickel and copper complexes are shown to oxidize 2-arylcyclohexanones (Ar = Ph, 4-ClC6H4,4-MeOC6H4) in rather high yield with ee up to 69%, pivalaldehyde... 

Baeyer-Villiger oxidation of cyclohexanone is used for the preparation of e-... 

The Baeyer-Villiger oxidation of cyclohexanone to the seven-membered lactone used aqueous formic acid (5% water) as medium, and a 60% conversion at 88% selectivity was found [313]. 

Illustration of the simultaneous determination of intermolecular and intramolecular 13C and 2H KIEs at natural abundance are studies of the Baeyer-Villiger (B-V) oxidation of cyclohexanone to s-caprolactone.48... 

---