Oxidative Dehydrogenation of Hydrocarbons

Abstract

The many-body problem of finding a correlation potential in an electron gas is solved as a two-electron problem. The resulting correlation potential for a constant density compares well with other local-density potentials for a wide range of different densities. The formalism is extended for non-constant electron densities and spin-polarisation. For nonlocal exchange we use a simple rescaling of the Kohn-Sham potential, in which non-locality up to a certain cut-off radius is included. It is argued that the obtained formalism is applicable for relatively high densities in which the exchange-correlation hole is small in comparison with the size of a lobe of an atomic wavefunction. Applications for V. Cu. Nb. Pd, Ni, Fe, and Ce usingself-consistent linear-muffin-tin-orbital (LMTO) band calculations give in general improved Fermi Surface (FS) properties in all metals. In Li, having low electronic density, the FS does not change significantly from the local-density result. The formalism, with its advantages and shortcomings compared to other methods and calculated results, is discussed. 0953-8984/89/458865 + 12 $02.50 0 1989 I O P Publishing Ltd

Microstraining in titania-, alumina- and silica-supported V2O5-catalysts

“…[1][2][3][4] The ODP reaction (oxidative dehydrogenation of propane) may be seen as one model reaction for olefin processing to produce propene at low temperatures. The reaction requires a contact of the gas molecule to solid-state catalyst which donates oxygen to react with two hydrogen species of the gas.…”

Oxidative Dehyrodimerization of Methane Using Manganese-based Catalysts Made by Self-propagating High-temperature Combustion Synthesis

“…Thermal oxidative pyrolysis of methane produces only acetylene and various products of deep oxidation [1], whereas catalytic pyrolysis involves condensation of two molecules to one of a higher molecular weight and, since this takes place at lower temperatures, the predominant product is ethylene [2]. The first reports of dehydrodimerization of methane to ethylene using solid catalysts appeared over a century ago and the presently accepted mechanism of conversion in the presence of oxygen involves the dehydrogenation of methane to methyl radicals followed by recombination to ethylene.…”

Carbon Dioxide as Hydrogen Acceptor in Dehydrogenation of Alkanes

“…This catalyst may be regenerated with air in a fixed bed or recirculating bed, but the necessary related equipment requires an undesirably large capital investment for a commercial plant. Oxidative dehydrogenation is an obvious possibility, but it is difficult to achieve high catalytic selectivity from paraffins to desired products when air or oxygen is used (Skarchenko, 1968). As an alternative to these processes, carbon dioxide was investigated as an oxidant to effect dehydrogenation and coke removal by the following reactions:…”