Nitrobenzene Hydrogenation over Catalysts Cu based Supported on Activated Charcoal

Hydrogenation of nitrobenzene to amino aromatics was performed using catalysts Cu based supported on charcoal. Experiments were performed in a continuous sistem and fixed bed reactor at a pressure of 10-40 bar, and a temperature of 45-75 degrees C, with a weight hourly space velocities of nitrobenzene of 0.2 - 0.6 h(-1) and a molar ratio hydrogen/nitrobenzene of 10; nitrobenzene was diluted in n-heptane. Acid strength distribution of the two catalysts (1.5% Ru-5% Cu activated carbon and 5% Cu/activated carbon) where determined by termodesorption of diethyl amine. The major compounds identified in the hydrogenation of nitrobenzene were aniline, diphenylamine, diphenylhydrazine, azobenzene and nitrocyclohexane. It was observed that the conversion of nitrobenzene and aniline yield shows a parabolic variation with increasing of pressure, probably due to sintering of the catalyst at higher pressure, which is favored by high exothermicity of the hydrogenation process of nitrobenzene correlated with the increase of the proportion of nitrobenzene in liquid phase.