Catalytic chemistry, hydrocarbon partial

Hydrocarbon Partial Oxidation Catalysts Prepared by the High-Temperature Aerosol Decomposition Process Crystal and Catalytic Chemistry... 

An alternative approach to partial oxidation of methane is oxyhydrohalogenation— usually oxyhydrochlorination.31 In this alternative chemistry modification, methane is converted first to methyl chloride in a reactor fed a mixture of HC1, steam, and methane. The intermediately formed methyl chloride then is converted in a second catalytic (zeolite) reactor to low-to-medium range hydrocarbons. The net reaction is ... 

Rare earth oxides are useful for partial oxidation of natural gas to ethane and ethylene. Samarium oxide doped with alkali metal halides is the most effective catalyst for producing predominantly ethylene. In syngas chemistry, addition of rare earths has proven to be useful to catalyst activity and selectivity. Formerly thorium oxide was used in the Fisher-Tropsch process. Recently ruthenium supported on rare earth oxides was found selective for lower olefin production. Also praseodymium-iron/alumina catalysts produce hydrocarbons in the middle distillate range. Further unusual catalytic properties have been found for lanthanide intermetallics like CeCo2, CeNi2, ThNis- Rare earth compounds (Ce, La) are effective promoters in alcohol synthesis, steam reforming of hydrocarbons, alcohol carbonylation and selective oxidation of olefins. 

As discussed above in the reforming of hydrocarbon fuels, H2 can be produced from alcohol fuels by at least three major catalytic processes, namely steam reforming, partial oxidation and ATR or oxidative steam reforming. The chemistry, thermodynamics, and recent developments in catalysis of methanol and ethanol reforming with steam for H2 production will be discussed in this section. 

The foregoing brief description of the catalytic properties, and physical, structural and surface chemistry of heteropoly oxometalates demonstrates the multifunctional capabilities of these solids in various processes. While in some respects similar in their properties and behaviour to zeolites some notable differences are evident. The properties of heteropoly oxometalates evidently depend predominantly but not entirely on the nature of the central and peripheral metal elements of the anion, but the contribution of the cation cannot be neglected. Nevertheless, there is convincing evidence that the terminal oxygen atoms of the anion play a central role in the mechanism of any catalytic process in which heteropoly oxometalates participate, and in particular in the conversion of methanol to hydrocarbons and the partial oxidation of methane. 

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