A low temperature reaction sequence for methane conversion

Lower alkanes are prepn. from methane under atm. conditions in a 2-step route in which methane is thermally activated. At 500-800 K, methane is decompd. by a Group VIII metal catalyst into H and different carbide or graphite surface intermediates. Subsequently, a particular surface carbonaceous intermediate produces higher hydrocarbons upon hydrogenation at 300-400 K. The temp. difference between the 2 reaction steps is a thermodn. stipulation; for bulk Co carbide, the temp. gap between the 2 reaction steps is 282 K at std. pressures. The transition-metal catalysts were prepd. by incipient-wetness impregnation of silica, dried, and reduced in situ at 600-800 K in H