Kinetics of selective partial oxidation of C-3-C-6 alpha-olefins over an iron antimony oxide catalyst

Various models have been tested to describe the influence of carbon number on the kinetics of the selective partial oxidation of alpha-olefins over iron antimony oxide. Modeling the rate of C-3-C-6 olefin consumption according to the Mars-van Krevelen redox mechanism showed that the rate constant for the reoxidation was dependent on the carbon number of the used olefin. This and the observed shifts in selectivities cannot be explained in terms of the simplified redox model. The rate of formation of the various product groups was modeled using a power law rate model and mechanistic models on the basis of the single-site Langmuir-Hinshelwood mechanism and on an oxidation mechanism. Using either of the two mechanistic models, one can conclude that the partial oxidation/dehydrogenation products are formed on similar sites, whereas the double-bond isomerization seems to occur on a different site. The kinetic parameters were evaluated as a function of the chain length of the feed molecule.