MoVTeNb oxide

A possible economically attractive alternative would be the production of acrylic acid in a single step process starting from the cheaper base material propane. In the nineteen nineties the Mitsubishi Chemical cooperation published a MoVTeNb-oxide, which could directly oxidise propane to acrylic acid in one step [6], Own preparations of this material yielded a highly crystalline substance. Careful analysis of single crystal electron diffraction patterns revealed that the MoVTeNb-oxide consists of two crystalline phases- a hexagonal so called K-Phase and an orthorhombic I-phase, which is the actual active catalyst phase, as could be shown by preparing the pure phases and testing them separately. 

Sanfiz AC, et al. Dynamics of the MoVTeNb oxide Ml phase in propane oxidation. J Phys Chem C. 2010 114(4) 1912-21. 

Figure 4.2.6 Scanning electron micrograph of a spray-dried oxalate precursor of MoVTeNb oxide.

Figure 4.2.9 SEM image of polycrystalline MoVTeNb oxide composed of the crystalline phases Ml (red) and M2 (yellow). The crystals were colored artificially for better visualization.

Figure 4.2.13 Content (wt%) of the crystalline Ml phase obtained by activation of a single, amorphous MoVTeNb-oxide precursor in argon in a rotating oven at different temperatures and argon flow rates.

Popova GY, Andrushkevich TV, Aleshina GI, Plyasova LM, Khramov MI. Effect of oxalic acid content and medium of thermal treatment on physicochemical and catalytic properties of MoVTeNb oxide catalysts in propane ammoxidation. Applied Catalysis A General. 2007 328(2) 195-200. 

Maksimovskaya RI, Bondareva VM, Aleshina GI. NMR spectroscopic studies of interactions in solution during the synthesis of MoVTeNb oxide catalysts. European Journal of Inorganic Chemistry. 2008 2008(31) 4906-4914. 

Popova GY, Andrushkevich TV, Dovlitova LS, Aleshina GA, Chesalov YA, Ishenko AV, Ishenko EV, Plyasova LM, Malakhov W, Khramov MI. The investigation of chemical and phase composition of solid precursor of MoVTeNb oxide catalyst and its transformation during the thermal treatment. Applied Catalysis A General. 2009 353(2) 249-257. 

Girgsdies F, Schlogl R, Trunschke A. In-situ X-ray diffraction study of phase crystallization from an amorphous MoVTeNb oxide catalyst precursor. Catalysis Communications. 2012 18(0) 60-62. 

Celaya Sanfiz A, Hansen TW, Girgsdies F, Timpe O, Rodel E, Ressler T, Trunschke A, Schlogl R. Preparation of phase-pure Ml MoVTeNb oxide catalysts by hydrothermal synthesis-influence of reaction parameters on structure and morphology. Topics in Catalysis. 2008 50(l t) 19-32. 

Kolen ko YV, Zhang W, Naumann d Alnoncourt R, Girgsdies F, Hansen TW, Wolfram T, Schlogl R, Trunschke A. Synthesis of MoVTeNb oxide catalysts with tunable particle dimensions. ChemCatChem. 2011 3(10) 1597-1606. 

Sanfiz AC, Hansen TW, Teschner D, Schnihch P, Girgsdies F, Trunschke A, Schlogl R, Looi MH, Abd Hamid SB (2010) Dynamics of the MoVTeNb Oxide Ml Phase in Propane... 

Formation of active component of MoVTeNb oxide catalyst for selective oxidation and ammoxidation of propane and ethane... 

Formation of the active component of MoVTeNb oxide catalysts includes the following stages (i) formation of compounds with heteropolyanion (HPA) structure at the step of initial solutions mixture, (ii) drying of the wet precursor with the HPA structure being retained, (iii) decomposition of the dried precursor upon low-temperature treatmeut leading to amorphous product that contains nanosize particles with the structure and composition close to those of Ml and M2 phases, and (iv) ciystallization of Ml and M2 phases upon calcination in helium flow at 600°C. The slurry pH affects the nature and composition of the cmde and dry precursors as well as the chemical composition and M1/M2 ratio of the final catalyst. The most effective catalyst is prepared at pH=3.0 when a maximum content of Ml phase is formed. 

Ivars F, Solsona B, Hernandez S, Lopez Nieto JM. Influence of gel composition in the synthesis of MoVTeNb catalysts over their catalytic performance in partial propane and propylene oxidation. Catalysis Today. 2010 149(3 4) 260 266. 

Beato P, Blume A, Girgsdies F, Jentoft RE, Schlogl R, Timpe O, Trunschke A, Weinberg G, Basher Q, Hamid FA, Hamid SBA, Omar E, Mohd Salim L. Analysis of structural transformations during the synthesis of a MoVTeNb mixed oxide catalyst. Applied Catalysis, A General. 2006 307(1) 137-147. 

Table 6.5 XPS binding energies of the Ml phase MoVTeNb materials under reaction conditions (see Figure 6.12) in comparison with reference binary oxides measured under oxygen at elevated temperature (623-673 K). At these conditions charging was practically not observed. Experiments used low kinetic energy electrons, and hence were sensitive to the topmost layers.

Actually, the major success in propane ammoxidation into acrylonitrile has been to discover MoVTeNb mixed oxide materials presenting a crystalline phase with a so-called Ml structure, since the results obtained with this type of catalyst are remarkably better than those from the other catalytic systems reported for propane ammoxidation. In fact, the complex structure of the... 

Lopez Nieto, J., Botella, R, Vazquez, M., et al. (2002). The Selective Oxidative Dehydrogenation of Ethane over Hydrothermally Synthesized MoVTeNb Catalysts, Chem. Commun., 17, pp. 1906-1907. 

L6pez Nieto, J., Solsona, B., Concepcion, R, et al. (2010). Reaction Products and Pathways in the Selective Oxidation of C2-C4 Alkanes on MoVTeNb Mixed Oxide Catalysts, Catal. Today, 157, pp. 291-296. 

Keywords MoVTeNb mixed oxide Ml, M2 phase ethane propane (armn)oxidation... 

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