Cyclic processes methane

Koppers Hasche A cyclic process for converting methane to syngas by partial oxidation over an alumina catalyst ... 

Fig. 4.9 A modification of the cyclic process in Fig. 4.5. Instead of transferring a hypothetical dimer, we first replace the two monomers s (here, methane molecules) by one ethane molecule, and then transfer the real ethane molecule into the liquid. 

Isomerization of nitroso compounds to the corresponding oxime is rapid at temperatures above the melting point of the dimer or in the presence of metallic or other reactive surfaces or in certain non-aqueous solvents . For the nitroso-methane-formaldoxime isomerization the activation energy was estimated as 30-40 kcal.mole . The thermal gas-phase isomerization of nitrosomethane, reaction (1), has been studied by a flow technique at low pressures, and found to be highly sensitive to reaction conditions, especially to the nature and extent of the surfaces. Under conditions favourable to the homogeneous gas phase process, 27.1 kcal.mole and log /l(sec ) = 8.9. The low pre-exponential factor was interpreted in terms of a cyclic transition state, viz. 

In the gas phase reaction of Rh with c-CaH, among other processes, elimination of C2H4 has been observed and the resulting metal ion was shown to have the structure of a methylidene-rhodium complex (238) instead of a hydrido-methylidene species (239) . RhCHa (238) reacts readily with H2 and CH4 and represents the first example of methane activation by a cationic mononuclear transition-metal complex in the gas phase. Reactions of both Rh = CH2 and its analogues Fe-CH2 and C0-CH2 with cyclic hydrocarbons were studied, and it is assumed that in the initial step metallacycloalkanes are generated (Scheme 35). 

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