Kinetics of the Hydrogenation of Aniline in the Vapor Phase on a Cobalt-Alumina Catalyst

Abstract

Abstract The kinetics of the catalytic hydrogenation of aniline with a cobalt-alumina catalyst in the temperature range from 160° to 210°C was studied by a differential flow reactor with a fixed bed. (1) The rate of reaction reaches a maximum in the 180–190°C range for the hydrogenation of aniline. From the thermodynamic calculations and the experimental results for a fluidized-bed reactor, the reverse reaction was found to be almost negligible below 200°C under the conditions of the reaction. This phenomenon was explained by the proposed kinetics of the reaction. (2) The initial rate of reaction without cyclohexylamine, and the rate when some cyclohexylamine was added to the reactants, were measured at atmospheric pressure over the following range of conditions of partial pressures; hydrogen 0.3–0.92 atm., aniline 0.05–0.2 atm., cyclohexylamine 0–0.24 atm. It was concluded that a plausible rate-controlling step was the surface reaction, i. e., the reaction between the adsorbed aniline and hydrogen on the surface of the catalyst. The equation for the vapor phase hydrogenation of aniline on a cobalt-alumina catalyst in the temperature range from 150°C to 210°C was determined to be: r=k\fracKH3KAPH3PA(1+KHPH+KAPA+KCPC)4