Synthesis gas formation by direct

Synthesis Gas Formation by Direct Oxidation of Methane over Monoliths... 

D A. Hickman and L.D. Schmidt, Synthesis gas formation by direct oxidation of methane over monoliths. Symposium on Catalytic Selective Oxidation, Washington, DC, pp. 1263-1267 (1992). 

From the data shown in Fi re 1, two key points are evident (1) increasing the adiabatic reaction temperature increases the selectivity of synthesis gas formation, especially Sh2 and (2) Rh is a better catalyst than Pt for producing H2 by direct oxidation of CH4. 

The combination of reactions (2) and (5) may be considered as a scheme for direct methane oxidation to synthesis gas (CO -f H2). Similar reactions may determine the high efficiency of mixed catalysts containing Ni and rare-earth oxides for the partial oxidation of methane to synthesis gas [9]. This mechanism does not require a preliminary total oxidation of methane followed by its reforming with CO2 and/or water which was considered as the main route for synthesis gas formation [10,11]... 

Chem Systems Inc. proposed a process in which ben2yl alcohol obtained by an undisclosed direct oxidation of toluene is homologated with synthesis gas to yield 2-phen5iethyl alcohol, which is then readily dehydrated to styrene (57). This process eliminates the intermediate formation of methanol from synthesis gas but does require the independent production of ben2yl alcohol. 

We next consider the synthesis and chemical reactions of the oxides of chlorine. Because the compounds are strongly endothermic and have large positive free energies of formation it is not possible to prepare them by direct reaction of CI2 and O2. Dichlorine monoxide, CI2O, is best obtained by treating freshly prepared yellow HgO and CI2 gas (diluted with dry air or by dissolution in CCI4) ... 

Perhaps the most effective synthesis, albeit an expensive one, involves the direct methylation of alkylimidazoles using trimethyloxonium tetrafluoroborate with concomitant formation of the tetrafluoroborate anion as shown in Scheme 4.3 [12]. This is a single step reaction in which no chloride is present at any stage of the synthesis. The only by-product from this reaction is dimethyl ether which is a volatile and inert gas and it is easily removed. 

Much recent research (7-5) has been devoted to converting methane to products that are more easily transported and more valuable. Such more valuable products include higher hydrocarbons and the partial oxidation products of methane which are formed by either direct routes such as oxidative coupling reactions or indirect methods via synthesis gas as an intermediate. The topic of syngas formation by oxidation of CH4 has been considered primarily from an engineering perspective (7-5). Most fundamental studies of the direct oxidation of CH4 have dealt with the CH4 + O2 reaction system in excess O2 and at lower temperatures (6-10). 

Shultz, Seligman, Shaw, and Anderson (5) attempted to prepare nitrides by treating raw (oxide) iron catalysts directly with ammonia. An analogous reaction, the formation of iron carbides by treatment of raw precipitated catalysts with carbon monoxide or synthesis gas, can be carried out at temperatures between 200° and 325°C. However, ammonia treatment of a precipitated catalyst (Fe203-Cu0-K2C03, Bureau of Mines number P3003.24) at 300°, 350°, and 400°C. resulted... 

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