AbstractIn the development of a pilot unit for studying reactions involving heterogeneous catalysis a nickel catalyst was selected for the initial study, and the hydrogenation of benzene in a fluidized reactor using nickel and nickel oxide supported on silica gel was investigated for the reaction C6H6+ 3 H2→ C6H12at temperatures of 150—220° for the nickel oxide study and 220–275° for nickel, pressures being 25–100 p.s.i.g. and molal ratios of hydrogen to benzene ranging from 0·5 to 3·9. The data were correlated with an equation of the form\documentclass{article}\pagestyle{empty}\begin{document}$ \[r = \frac{{k_e K_{H_2 }^3 K_B p_{H_2 }^3 p_B }}{{\left({1 + K_{H_2 } p_{H_2 } + K_B p_B } \right)^4 }} \] $\end{document}By observing how the history of the catalyst affects its activity some of the known erratic behaviour of nickel catalysts is now better understood. The reported rate equation and constants for various activity levels for nickel catalyst enable a more intelligent design of chemical reactors employing th