The Catalytic Hydrogenation of Aniline

Abstract 1) The order of the activity of a metal catalyst for the hydrogenation of aniline is Co>Ni>Fe, Cu. The order of their selectivity is Co>Ni. 2) The activity of the mixed metals (Co-Ni, Co-Fe) is lower than that of a cobalt single catalyst. 3) The rate of hydrogenation increases with the temperature up to 180–200°C, and then decreases at higher temperatures. This phenomenon may be explained in terms of the kinetics of the reaction. 4) The catalyst which consists of a complex between the metal and its carrier-oxide is less active than the free metal catalyst for the hydrogenation reaction, and it almost completely loses its activity for the hydrogenolysis reaction. 5) The production of cyclohexylamine is affected by the property of the carrier oxide. 6) The main course of the production of dicyclohexylamine is considered to proceed through the condensation of two cyclohexylamine molecules and through N-cyclohexylidene-cyclohexylamine. Notation:r. p. c.=relative partial charge on the oxygen of oxide (reported by R. T. Sanderson) −ΔH0°=standard heat of formation of the higest oxide per metal g.-atm.