Kinetics of the Catalytic Vapor Phase Reduction of Nitrobenzene

Abstract

The kinetics of the catalytic vapor phase reduction of nitrobenzene to aniline over copper-magnesia catalyst in the temperature range from 175°C to 220°C was studied using a differential reactor. The rate of reaction was measured at atmospheric pressure with a high mole ratio of hydrogen to nitrobenzene. From the analysis of the experimental data, it was concluded that the rate-controlling step was the adsorption process of hydrogen on the copper-magnesia catalyst surface. According to the Langmuir-Hinshelwood mechanism, the final rate equation r for the vapor phase reduction of nitrobenzene on copper-magnesia catalyst in the temperature range from 175°C to 220°C was obtained as follows;r=kPH/1+KNPN+KAPA+KWPWwhere k; rate constantPH, PN, PA and PW; partial pressure of hydrogen, nitrobenzene, aniline and waterKN, KA and KW; adsorption equilibrium constant of nitrobenzene, aniline and waterThis equation will be useful if it can be used to predict the rate over a wide range of reactions and hence, be suitable for reactor design.