Gas-chromatographic studies of hydrocarbon hydrogenolysis on a Ni/SiO2 catalyst

Abstract

The hydrogenolysis of hydrocarbons on a Ni/SiO₂ catalyst has been studied using a wide variety of unconventional gas-chromatographic techniques, especially those involving the gas-chromatographic properties of the catalyst itself. Under 1 atm of hydrogen, reaction takes place via terminal cleavage with an unusually high apparent activation energy, which suggests a mechanism involving the breaking of many C—H bonds before the C—C bond. This is supported by the lowering of this activation energy at lower hydrogen pressures (0.01 atm) when the rate-determining step becomes defined as the generation of methane from the surface. At very low hydrogen pressures (nitrogen carrier gas) various surface rearrangement reactions have been observed giving chiefly C₅ and C₆ rings in addition to methane.