Methane photochemistry ethane formation

The photochemistry of Titan s atmosphere can be summarized as follows the unsaturated compounds are formed from HCN and C2H2, which is derived from CH4. Methane decomposition leads to further ethane formation. 

Both neutral and charge-transfer photochemistry is involved in the photodissociation at 248 nm of methyl iodide as a monolayer (1 ML) or up to 10 ML on a silverfl 11) surface. Such reactivity involves the fission of the C—I bond and the formation of methyl radicals and iodide adsorbed at the surface12,13a. Dissociation also occurs during X-ray photoelectron spectroscopy136. Multilayers of methyl iodide on silverfl 11) surfaces undergo C—I bond fission on irradiation at 248 nm. Several products such as ethane, ethyl iodide and iodoform are formed but the principal reaction path, which is somewhat time-dependent, yields methane and methylene di-iodide14. 

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