Vanadium carbide, synthesis

Janes, A. Synthesis and characterization of nanoporous carbide-derived carbon by chlorination of vanadium carbide. Carbon 45, 2007 2717-2722. 

F. Meunier, P. Delporte, B. Heinrich, C. Bounchy, C. Crouzet, C. Pham-Huu, P. Panis-sod, J. Lerou, P. Mills and M. Ledoux, Synthesis and characterization of high specific surface area vanadium carbide application to catalytic oxidation, J. Catal., 169, 33—44 (1997). 

The carbides and nitrides were also found to be active in ammonia decomposition. The activities of vanadium carbides were 1-2 orders of magnitude lesser than that of Mo nitride catalyst, but 1-2 orders of magnitude higher than that of a Pt/C catalyst (138). Vanadium carbides were 1 order of magnitude more active than vanadium nitrides. Both the synthesis and decomposition of NH3 were found to be structure-sensitive reactions over carbide and nitride catalysts with activities depending strongly on the particle sizes of the catalysts. 

Carbides of metals and other elements have been produced by this approach, including carbides of boron, silicon, titanium, zirconium, hafnium, vanadium, niobium, molybdenum, tungsten, tantalnm, and thorium (Funke, Klementiev, Kosukhin, 1969 Sheppard Wilson, 1972 MacKinnon Wickens, 1973 Chase, 1974 Steiger Wilson, 1974 Swaney, 1974 MacKinnon Renben, 1975). The produced caibide particles are very small their diameter is usually about 20-200 mu. Halides are mixed with hydrocarbons, usually in a ratio H2 Me = 2-30. The gas mixture is heated up in plasma to temperatures of 1300-4000 K time of synthesis exceeds 50 ms. As an example, production of submicron boron carbide powder from gaseous boron trichloride and methane occurs in the strongly endothermic process ... 

Recently, the Yankee Atomic Electric Company, Environmental Laboratory, has determined the tritium levels in water samples from the environs of several nuclear generating facilities in the New England area by liquid scintillation analysis of high purity tritiated benzene prepared from the water samples to be quantified. A commercially available unit was utilized to facilitate the synthesis of benzene by reacting the water sample with calcium carbide to form tritiated acetylene which is subsequently trimerized on a vanadium catalyst to high purity tritiated benzene. 

This chapter presents a review of the synthesis of vanadium, niobium, and molybdenum carbides and nitrides by the TPR method. Factors responsible for development of surface area during transformation are discussed. 

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