Direct methane conversion routes to chemicals and fuels

Recent Advances in Catalytic/Biocatalytic Conversion of Greenhouse Methane and Carbon Dioxide to Methanol and Other Oxygenates

“…The gas-phase non-catalytic reactions usually occur via a free radical mechanism at high temperatures which are unfavourable with respect to the control of selectivity of the desired oxygenates (Navarro et al, 2006;Alvarez-Galvan et al, 2011). Thermodynamic and kinetic analyses have shown that the rate-limiting step of the partial oxidation of methane is the first H-abstraction from the C-H bond to form methyl radicals (Navarro et al, 2006;AlvarezGalvan et al, 2011).…”

“…Thermodynamic and kinetic analyses have shown that the rate-limiting step of the partial oxidation of methane is the first H-abstraction from the C-H bond to form methyl radicals (Navarro et al, 2006;AlvarezGalvan et al, 2011). Thus, initiators and sensitizers have been incorporated into the reaction mixture for the purpose of lowering the energy barrier of this H-abstraction (Navarro et al, 2006;Alvarez-Galvan et al, 2011). In particular, nitrogen oxides have been used to promote gas-phase reactions with methane (Otsuka et al, 1999;Tabata et al, 2000;Babero et al, 2002;Tabata et al, 2002).…”

“…This direct conversion route involves partial oxidation at 300-500 °C under fuel-rich mixtures to minimize the extent of the more thermodynamically favourable combustion reaction which produces unwanted CO and CO 2 (Zhang et al, 2003;Navarro et al, 2006;Alvarez-Galvan et al, 2011). Several reviews which provided valuable discussions of various aspects of, and the progress already made in, the direct partial oxidation of methane to methanol and other oxygenates have been published (Foster, 1985;Gesser et al, 1985;Edwards & Foster, 1986;Pitchai & Klier, 1986;Fujimoto, 1994;Yang et al, 1997;Adebajo, 1999;Lunsford, 2000;Tabata et al, 2002;Zhang et al, 2003;Taniewski, 2004;de Vekki & Marakaev, 2009;Holmen, 2009;Alvarez-Galvan et al, 2011). The selective partial oxidation of methane has been carried out in four ways, namely high temperature non-catalytic gas-phase homogeneous oxidation, heterogeneous catalytic oxidation, low temperature homogeneous catalysis in solution and enzymatic or biological catalytic oxidation (Zhang et al, 2003;Holmen, 2009).…”

Reaction of nitrous oxide with methane to synthesis gas: A thermodynamic and catalytic study

“…A number of research groups are focussing their research on the development of catalysts for direct (bypassing synthesis gas production) conversion of CH 4 to fuels and chemicals [14]. On the other hand, there are various approaches to indirect A C C E P T E D M A N U S C R I P T 4 conversion methods, in which CH 4 is first converted in to synthesis gas which is then transformed into various useful chemicals [15].…”

Engineering evaluation of direct methane to methanol conversion

“…There is a considerable body of literature on the process chemistry of direct methane to methanol conversion [4]. It is one of a class of processes that involves the reaction of methane with an oxidant and direct oxidative methane conversion is often discussed collectively [5,6,7,8]. Studies that consider the engineering aspects of processes for direct oxidative methane conversion are less abundant [9,10].…”