Oxidation of ethane and cyclohexane over vanadia-niobia-silica catalysts

• Published in: Applied catalysis. A, General Vol. 251; no. 1; pp. 29 - 38
• Main Authors: Resini, Carlo, Panizza, Marta, Raccoli, Fabio, Fadda, Michela, Carnasciali, Maria M., Busca, Guido, Lopez, Enrique Fernandez, Escribano, Vicente Sanchez
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25-09-2003; Elsevier
• Subjects: Catalysis; Catalysts characterization; Catalytic reactions; Chemistry; Cyclohexane oxidation; Ethane oxidation; Exact sciences and technology; General and physical chemistry; Niobium oxide; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Vanadium oxide; Vanadium oxide; Ethane oxidation; Niobium oxide; Cyclohexane oxidation; Catalysts characterization; Mixed catalyst; Hydrocarbon; Ethylene; Cycloalkane; Supported catalyst; Ethane; Heterogeneous catalysis; Transition metal compounds; Benzene; Alkane; Cyclohexane; Silicon Oxides; Oxidation
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/S0926-860X(03)00296-5

The conversion of ethane and cyclohexane in the presence of oxygen has been investigated on vanadia-silica (VS), niobia-silica (NS) and 1:1 vanadia-niobia-silica (VNS) catalysts. Vanadia-silica is an active catalyst for the production of ethylene from ethane and of benzene from cyclohexane. Selectivity to ethylene near 60% is obtained at near 10% ethane conversion near 820
K. Selectivity to benzene declines from above 70 to 40% when conversion of cyclohexane grows up to 40%. Cyclohexene is produced only after total oxygen conversion. Niobia-silica is much less active than vanadia-silica, and the selectivities to ethylene and to benzene grow by increasing conversion up to approach those obtained in the empty reactor at very high temperatures (above 900–1000
K). The vanadia-niobia-silica catalyst behaves quite like the vanadia-silica catalyst.
Raman, UV-Vis and XRD characterization experiments show that V
2O
5 particles are present both in vanadia-silica and in niobia-vanadia-silica. On the contrary niobium oxide is present as amorphous phase and traces of V-Nb mixed oxide are found in the V-Nb-silica catalyst.