Selective oxidation of cyclohexane

The selective oxidation of cyclohexane to cyclohexanol and cyclohexanone has been studied by Suo and co-workers [395,396]. This reaction is a key process in the chemical industry, for the oxidation products of cyclohexane, via cyclohexanol and cyclohexanone, are important intermediates in the manufacture of nylon-6 and nylon-66 polymers and are also used as solvents for lacquers, shellacs and varnishes as well as stabilisers and homogenisers for soaps and S3mthetic detergent emulsions. 

TABLE 1. Selective oxidation of cyclohexane with molecular oxygen over MnAPO-5 in different solvents. ... 

Selective Oxidation of Cyclohexane over Rare Earth Exchanged Zeolite Y... 

Although La-ZSM-5 has been reported as a selective catalyst in the oxidation of phenol with N20 to give / -hydroquinone with a selectivity of 82.1% (Deng et al. 1997), Ce-containing microporous materials have been the most studied catalysts in redox processes. Thus, Ce-Y zeolite has been used in the complete oxidation of methylene chloride in air (Chatteijee and Greene 1991). However, Ce-modified zeolites can also be used in selective oxidation reactions. This is the case for the selective oxidation of /7-xylene at 130°C on Ce-containing Mordenite (Hasimoto et al. 1997) or the selective oxidation of cyclohexane on Ce-exchange Y (Pires et al. 1997). Recently, it has been... 

Pires, E.L., M. Wallau and U. Schuchardt, 1997, Selective oxidation of cyclohexane over rare earth exchanged zeolite Y, in 3rd World Congr. on Oxidation Catalysis, eds R.K. Grasselli, S.T. Oyama, A.M. Gaflhey and J.E. Lyons, Vol. 110 of Studies in Surface Science and Catalysis (Elsevier, Amsterdam) pp. 1025-1027. 

Initially, all commercial processes for selective oxidation of cyclohexane were performed in the liquid phase with an oxygen-containing gas, in general air, and were catalyzed by transition metals. Both the formation ofthe intermediate CHHP and the decomposition of this intermediate are catalyzed by transition metals. 

Selective oxidation of cyclohexane to cyclohexanol and cyclohexanon is a very important reaction for the industrial production of adipic acid and caprolactam, which are the main raw materials for the manufacture of nylon. The conventional process is based on a homogeneous catalytic oxidation with cobaltdil) acetate as a catalyst. During this process, many unwanted coproducts are formed such as allqrl acetates other ketenes, or alkyl chlorides. Moreover, most industrial processes of the adipic acid production involve the nitric acid oxidation of cyclohexanol. Taking into account that the worldwide adipic acid production is more than 2 million metric tons per year (359), it has been evident that despite the... 

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-... 

Zhang, R., Qin, Z., Dong, M., et al. (2005). Selective oxidation of cyclohexane in supercritical carbon dioxide over CoAPO-5 molecular sieves, Catal. Today, 110, pp. 351-356. 

Hessel et al. described a full process design vision for the manufacturing of adipic acid on an industrial scale [66,67]. Currently, commercial production of adipic acid comprises two reaction steps. The first step involves the selective oxidation of cyclohexane to KA oil, a mixture of cyclohexanone and cyclohexanol. The second step consists of oxidation of the KA oil to adipic acid with an excess of nitric acid in the presence of copper or vanadium catalysts. In contrast, Hessel et al. suggest that a new and direct route toward adipic add based on the direct oxidation of cyclohexene with hydrogen peroxide would be much more cost effective. This process is based on the protocol described by Noyori and coworkers and utilizes a... 

A new approach for the dispersion of VOPO4.2H2O through exfoliation and its catalytic activity for the selective oxidation of cyclohexane... 

It is evident that the VOPO4.2H2O phase can be exfoliated in 2-propanol and dispersed on alumina with retention of the original stractuie. The ciystallinity, crystallite size, and morphology, are dependent upon the VPO alumina ratio and the activity of the different phases for the selective oxidation of cyclohexane varies accordingly. The present work therefore provides a novel approach for preparing dispersed VPO phases whose stractural characteristics and consequently their catalytic activity can be controlled through the VPO alumina ratio. 

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