This chapter summarizes the data and current understanding regarding the oxidative dehydrogenation reaction of alkanes. The reaction mechanism, the nature of the catalysts, and factors that determine selectivity for dehydrogenation versus formation of oxygen-containing products are discussed in the chapter. From the pattern of product distribution in the oxidation of C2 to C6 alkanes obtained with supported vanadium oxide, orthovanadates of cations of different reduction potentials, and vanadates of different bonding units of VOx in the active sites, it is shown that the selectivities can be explained by the probability of the surface alkyl species (or the surface alkene formed from the alkyl) to react with a reactive surface lattice oxygen. Catalysts for which this occurs with a high probability would show low selectivities. This probability increases for vanadates that have low heats of removal of lattice oxygen, which are those that contain easily reducible cations in the active sites and for vanadates whose active sites can bind the surface alkyl species (or alkene) in a way that bring the surface intermediate close to the reactive lattice oxygen. The dependence of selectivity for dehydrogenation on the conversion of alkane shows that for the more selective catalysts known, the reaction proceeds with a sequential mechanism.
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