Arne Dinse

High performance (VOx)n–(TiOx)m/SBA-15 catalysts for the oxidative dehydrogenation of propane

Grafted VxOy catalysts for oxidative dehydrogenation of propane (ODP) have been studied due to their potential high performance and as model catalysts in the past. We report on a positive synergetic effect capable of considerably enhancing the propene productivities above reported performances. The most productive catalysts were found at metal loadings (V + Ti) close to the monolayer coverage. The 4V/13Ti/SBA-15 catalyst presented a considerably high productivity (6–9 kgpropene kgcat−1 h−1). Moreover, with this catalyst, propene productivity only slightly decreased as a function of propane conversion, indicating that propene combustion toward COx occurs more slowly in comparison to other catalysts exhibiting high propene productivities. A detailed kinetic analysis of the 4V/13Ti/SBA-15 catalyst revealed that high vanadia and titania dispersions are required for high propene productivity.

Characterization and Quantification of Reduced Sites on Supported Vanadium Oxide Catalysts by Using High‐Frequency Electron Paramagnetic Resonance

VOx (1.4–1.7 V nm−2) supported on SBA‐15, Al2O3, or TiO2 was studied before and after exposure to oxidative dehydrogenation of propane (ODP), and pure hydrogen or propane. After treatment, samples were quenched and frozen in quartz vials and characterized by using high‐frequency electron paramagnetic resonance (HF‐EPR). For SBA‐15‐ and Al2O3‐supported vanadia, V4+ sites were the most abundant paramagnetic species, whereas Ti3+ was dominant in TiO2‐supported V2O5. For the quantification of paramagnetic reduced sites, Mn2+ was used as reference. The maximum relative numbers of reduced V4+ or Ti3+ sites were found to increase in the sequence SBA‐15 (11 % V4+/V)

Chapter 16:Reaction Engineering of Oxidation Reactions

Going from analytical characterization of solid-state catalysts to their application in selected reactor systems on a laboratory or industrial scale, the chemist is confronted with several challenges that are related to the field of chemical engineering. The most important engineering aspects are summarized in the understanding of reaction kinetics, mass and heat transfer effects, residence time distribution, catalyst stability and reactor safety that shall therefore be addressed in this chapter. While the minimum requirements for the implementation of a chemical process are provided by the catalyst performance, the interplay of the mentioned parameters together with reactor design and operation mode state a powerful tool for further optimization of a chemical process. The field of reaction engineering mostly deals with questions regarding solely the reactor unit, while another important attribute of an industrial scale process is also the extensive product processing.