Reaction pathways and kinetics of the gas-phase oxidation of cyclohexane on NiO/γ-Al2O3 catalyst

A NiO/γ-Al2O3 catalyst with a nearly monolayer dispersion of active nickel oxide species on the carrier was synthesized and investigated for the selective oxidehydrogenation of cyclohexane to cyclohexene. Integral measurements were performed to determine the reaction network and products distribution and differential measurements for kinetic investigations. The kinetic study showed a mechanism change in the temperature range of 573–603 K. From 513 to 573 K the oxidation took place via electrophilic oxygen species and from 603 to 723 K with nucleophilic oxygen species. The reaction order of cyclohexane is 1.0 in the lower temperature range and 0.5 in the higher one.