Catalytic oxidation of cyclohexene

Oxalate 111 is formed when the reaction is carried out in the presence of air. In that case, catalytic oxidation of cyclohexene to cyclohexen-3-ol takes place. The alcohol reacts with... 

Effect of Platinum Oxidation State in the Catalytic Oxidation of Cyclohexene... 

The prevalence for epoxidation seems to be independent of the electronic structure of the porphyrin or the type of oxidant. For example, the catalytic oxidation of cyclohexene la with molecular oxygen and isobutyraldehyde in the presence of Fe3+(TPP)C1 (TPP = tetraphenylporphyrin) in 1,2-dichloroethane yielded exclusively the epoxide 4a and only trace amounts of the allylic alcohol 2a or ketone 3a, as demonstrated by Nam et al. [111]. 

Aqua(phosphine)ruthenium(II) complexes [121] are useful for activation of molecular oxygen, and catalytic oxidation of cyclohexene can be carried out with 1 atm of O2 [121a,bj. The ruthenium catalyst bearing perfluorinated 1,3-diketone ligands catalyzes the aerobic epoxidation of alkenes in a perfluorinated solvent in the presence of i-PrCHO [122]. Asymmetric epoxidations of styrene and stilbene proceed with 56-80% e.e. with ruthenium complexes 38-40 (Figure 3.2) and oxidants such as PhI(OAc)2, PhIO, 2,6-dichloropyridine N-oxide, and molecular oxygen [123-125]. 

M. Guo, Catalytic oxidation of cyclohexene to adipic acid with a reaction-controlled phase transfer catalyst. Chin. J. Catal. 24 (2003) 483. 

Our results with the CoNaY catalysts is quite comparable to the results of Lunsford and Dai [4]. They have reported the catalytic oxidation of cyclohexene with Co2,5NaY as catalyst and t-BuOOH as initator. They found a conversion of cyclohexene of 49.7 9 with a product distribution of 1-3 of 53.0, 39.4 and 6.0, respectively. 

Catalytic Activity and Product Distribution of the Catalytic Oxidation of Cyclohexene by... 

In order to unveil some of the details concerning the mechanism of the catalytic-oxidation of cyclohexene with CrY and NMP, some further experiments were performed. 

Influence of Different Parameters on the Catalytic Activity and Product Distribution of the Catalytic Oxidation of Cyclohexene by Metal-Exchanged Zeolite Y and l-Methyl-2-... 

Catalytic oxidation of cyclohexene and styrene were carried out with the following complexes... 

Catalytic oxidation of cyclohexene with cumene hydroperoxide gave 2 cyclohexen-l-ol and 2-cyclohexenone. Cydohexene oxide was not formed under the reaction conditions. The effect of various solvents on the oxidation reactions was smdied. The reaction was performed in polar, nonpolar, protic and aprotic solvents. Si ificant variation in product yield was observed. Table-1 shows the distribution of product yield with different solvents. Maximum conversion was observed in chloroform. The eflSciency of the catalyst for 2-cyclohexen-l-ol formation in chloroform is of the order, catalyst (2) > (3) > (1). When methanol was used as solvent the selectivity fijr epoxide was highest with catalyst (3), In this complex the selectivity fiar the formation of the allylic oxidation products are comparatively low. With catalyst (l),m methanol as solvent, 2-cyclohexen-l-ol was obtained in higher yield than eporade. With catalyst (1) the yield of the product was maximum when benzene was used as the solvent. Percentage conversion was the highest (39%). 

Catalytic oxidation of cyclohexene with NMO gave mainly 2-cyclohexenone.With complexes (2) and (3) minor amounts of 2-cyclohexen-l-ol was also formed. Table-3 shows the product yield with NMO as the oxidising agent. 

Catalytic oxidation of cyclohexene with CHP gave 2-cyclohexen-l-ol and 2-cyclohexenone respectively. In polar protic solvents epoxidation was significant. Oxidation of cyclohexene with NMO gave low conversion. The major product is 2-cyclohexenone. Styrene does not react with NMO under the reaction conditions. Oxidation of styrene with CHP gave benzaldehyde as the predominant product. 

However, catalytic oxidations of cyclohexene or ethylbenzene in the presence of RhCl(PPh3)3 give the products characteristic of free-radical reactions 36 thus cyclohexene gives cyclohexenone, cyclohexenol, cyclohexyl hydroperoxide and unidentified products. 

The first inverse of the ship-in-bottle synthesis, in which the zeolite cage is constructed around a porphyrin template, was reported by Li and Zhan. " The Fe(II) and Mn(II) derivatives of tetra(Af,A, Af-trimethylanilinium)porphyrin and H2(TMPyP) were used as cationic templates in zeolite hydrothermal synthesis. Attempts to incorporate an anionic porphyrin species, metallo-tetra(4-sulfunatophenyl)por-phyrin, were unsuccessful and trials with neutral TPP species resulted in trace encapsulation. High activity for the catalytic oxidation of cyclohexene by terf-butyl hydroperoxide was reported. 

Table 11.7. Catalytic oxidation of cyclohexene with hydrogen peroxide ...

Figure 12 Phase transfer catalytic oxidation of cyclohexene to adipic acid in an aque-0US/SCCO2 medium. (From Ref. 24.)...

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