The interaction of hydrocarbons with copper$z.sbnd;nickel and nickel in the formation of carbon filaments

We have carried out a comprehensive investigation of the interaction of selected hydrocarbons with coppernickel and nickel catalysts. Detailed analysis of both the yield of gaseous products and the amount of solid carbon deposited on the catalyst surfaces has enabled us to account for the entire course of the reaction and postulate the structural arrangements of reactive intermediates formed in the various systems. The excessive amount of methane produced from the coppernickel/ethylene interaction cannot be accounted for purely on the basis of hydrogasification and is believed to result from the formation of an “ethylidyne” intermediate. In contrast, nickel forms a strong bond with both carbon atoms in the hydrocarbon and in this case only minor amounts of methane are produced. It was found that coppernickel reacted very readily with ethylene at 600°C, whereas under the same conditions the presence of hydrogen was required to moderate interaction between the hydrocarbon and nickel. Both catalysts underwent direct reaction with acetylene at 600°C, but showed no tendency to decompose methane at temperatures below 900°C.