Carbon oxidation butane effect

In what concerns to products distribution, the effect of temperature is similar with both catalysts and corresponds to an increase in butane conversion the butenes selectivity decreases as the butadiene selectivity increases and the carbon oxides formation also increases, specially CO. These effects are more pronounced with the Cs doped sample. Butane partial pressure does not affect the products distribution with NiMo04 but increases the C4 s selectivity (specially butenes) decreasing mainly the CO2 formation with the 3% Cs doped catalyst. The effects of increasing P02 are the same for both catalysts. A decrease of C4 S selectivities and an increase of COx formation at low pressures is mainly observed. It is noteworthy that the main effects of Cs doping in the selectivities are increase in I-butene selectivity and decrease in CO formation. 

In a related publication, treatments with fumaric acid in a butan-2-ol/ethanol mixture and TCICA in butan-2-ol were compared [44]. In general, the TCICA was more effective at enhancing the peel strength achieved with a solvent-based PU adhesive. Infrared analysis indicated the treatments were probably effective by removing zinc stearate (reduction in peak at 1540 cm ) and the introduction of carbon-oxide functionalities (1704 cm and 1670 cm for the TCICA and fumaric acid, respectively). With TCICA, C-Cl bonds were also observed. 

Yang, B.L. Rung, H.H. (1982) Oxygen on iron oxide. Effect on the selective oxidation of butane. J. Catalysis 77 410-420 Yapp, C.J. Poths, H. (1986) Carbon in natural goethites. Geodiim. Cosmodiim. Acta 50 1213-1220... 

Direct evidence about the first step of activation of butane was obtained on a V-P oxide catalyst in the butane oxidation to maleic anhydride based on deuterium kinetic isotope effect (34). It was found that when a butane molecule was labeled with deuterium at the second and third carbon, a deuterium kinetic isotope effect of 2 was observed. No kinetic isotope effect was observed, however, if the deuterium label was at the first or fourth carbon. By comparing the observed and theoretical kinetic isotope effects, it was concluded that the first step of butane activation on this catalyst was the cleavage of a secondary C—H bond, and this step was the rate-limiting step. 

On an industrial scale, the traditional method for cleavage of carbon-carbon double bonds is ozonolysis, used for the manufacture of azelaic acid and nonanoic acids from oleic acid, and of butane tetracarboxylic acid from tetrahydrophthalic anhydride. The process is effectively a quantitative and mild process.178 However, it is capital and energy intensive. The intermediate ozonide is worked up either reductively or oxidatively to produce the aldehyde, ketone or carboxylic acid. Hydrogen peroxide is the common oxidizing agent used in the second step.179-181 Oxygen can also be used either alone182 or in combination with zeolites.183 Reviews on ozonolysis are available and the reader is directed to reference 184 for further information. 

Butane oxidation grew rapidly as the preferred process and is now dominant for maleic anhydride production for three reasons i) benzene is a valued petrochemical feedstocks whereas the cost of -butane is effectively that of a fuel a) the recognition of benzene as a carcinogen now requires the adoption of measures against its release in the workplace and in the environment and in) two of its carbon atoms are lost as carbon dioxide. 

Ge S, Liu C, Zhang S, Li Z (2003) Effect of carbon dioxide on the reaction performance of oxidative dehydrogenation of -butane over V-Mg-O catalyst. Chem Eng J 94 121-126... 

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