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The effect of supported MoOX structures on the reaction pathways of propene formation in the metathesis of ethylene and 2-butene

2014, Hahn, T., Kondratenko, E.V., Linke, D.

The kind of surface MoOX structures on Al2O3–SiO2 was found to determine propene selectivity in the metathesis of ethylene and 2-butene. Compared to isolated tetrahedral MoOX species, their polymerized octahedral counterparts show significantly lower activity for isomerisation of 2- to 1-butene thus hindering non-selective metathesis of these butenes. In addition, they reveal higher ability to engage ethylene in propene formation.

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Accessing heavy allyl-analogous [(TerN)2E]− (E = Sb, Bi) ions and their reactivity towards ECl3

2015, Hinz, Alexander, Schulz, Axel, Villinger, Alexander

The attempted preparation of the biradicaloid [E(μ-NTer)]2 (E = Sb, Bi) yielded salts of the anion [(TerN)2E]−. These heteroatom allyl analogues could be further utilized in the reaction with pnictogen(III) chlorides to form the first 1,3-dichloro-1-bisma-3-stiba-2,4-diazane [ClSb(μ-NTer)2BiCl].

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Control of coordinatively unsaturated Zr sites in ZrO2 for efficient C–H bond activation

2018, Zhang, Yaoyuan, Zhao, Yun, Otroshchenko, Tatiana, Lund, Henrik, Pohl, Marga-Martina, Rodemerck, Uwe, Linke, David, Jiao, Haijun, Jiang, Guiyuan, Kondratenko, Evgenii V.

Due to the complexity of heterogeneous catalysts, identification of active sites and the ways for their experimental design are not inherently straightforward but important for tailored catalyst preparation. The present study reveals the active sites for efficient C–H bond activation in C1–C4 alkanes over ZrO2 free of any metals or metal oxides usually catalysing this reaction. Quantum chemical calculations suggest that two Zr cations located at an oxygen vacancy are responsible for the homolytic C–H bond dissociation. This pathway differs from that reported for other metal oxides used for alkane activation, where metal cation and neighbouring lattice oxygen form the active site. The concentration of anion vacancies in ZrO2 can be controlled through adjusting the crystallite size. Accordingly designed ZrO2 shows industrially relevant activity and durability in non-oxidative propane dehydrogenation and performs superior to state-of-the-art catalysts possessing Pt, CrOx, GaOx or VOx species.