MOLECULAR CHEMISTRY OF ALKANE ACTIVATION

摘要

Organic iodo compounds are suitable to produce hydrocarbon fragments (CH_2, CH_3, C_2H_5 etc.) on metals surfaces of known composition. The formation and reactions of C_xH_y surface intermediates can be easily followed by spectroscopic methods of surface science. Depending on the nature of the metals, C_xH_y species react in different pathways. Whereas on platinum metals, CH_2 and CH_3 species are mainly selfhydrogenated into methane, on Cu and Ag surfaces their coupling is the dominant reaction. C_2H_5 undergoes dehydrogenation into ethylene on one hand, and hydrogenation into ethane on other hand. Recombination of C_2H_5 occurred only in the presence of Zn adatoms. Hydrocarbon fragments are combined with the adsorbed oxygen atoms even below 250-300 K to give different oxygenated compounds.