Reactivity of hexanes (2MP, MCP and CH) on W, W2C and WC powders. Part II. Approach to the reaction mechanisms using concepts of organometallic chemistry

Article abstract of DOI:10.1016/S1381-1169(97)00069-1

The reactivity of 2-methylpentane (2MP), methyleyelopentante (MCP) and cyclohexane (CH) on reproducible and well-characterized surfaces of W, W₂C and WC has been studied. A great deal of effort was put on the characterizations by physisorption, chemisorption and photoemission spectroscopy. The results obtained with these reference materials can be used for comparison with those appearing in the literature and sometimes debated because of the inconstancy of the active states due to non-stoichiometric compositions (excess of carbon, decarburization, oxidation by oxygen impurities). In agreement with the work of Boudart et al. [F.H. Ribeiro, R.A. Dalla Betta, M. Boudart, J. Baumbgartner, E. Iglesia, J. Catal. 130 (1991) 86; F.H. Ribeiro, M. Boudart, R.A. Dalla Betta, E. Iglesia, J. Catal. 130 (1991) 498; E. Iglesia, J.E. Baumgartner, E.H. Ribeiro, M. Boudart, J. Catal. 131 (1991) 523; E. Iglesia, F.H. Ribeiro, M. Boudart, J.E. Baumgartner, Catal, Today 15 (1992) 307.] we confirmed that reforming reactions do not take place in the temperature range 80-400°C and four experimental conditions. They dehydrogenation of cyclohexane appeared only when a strong position by carbonaceous residues occurred. For 2-methylpentane and methylcyclopentane the extensive hydrogenolysis character of WC is higher than for W₂C and WC surfaces are interpreted by different possible reaction intermediates deduced from concepts of organometallic chemistry.