Catalytic Hydrogenation of Dimethylnitrobenzene to Dimethylaniline Over Pd/C Catalysts

The catalytic transfer hydrogenation of dimethylnitrobenzene to dimethylaniline was studied in the temperature range 343–403, a pressure range of 4–10 bar H2 and ethanol as solvent using Pd/C as catalyst above agitation speed 800 rpm. The substrate feed concentration was varied in the range from 0.124 to 0.745 kmol/m3 while catalyst loading was in the range 4–12% (w/w) of dimethylnitrobenzene. Dimethylaniline was the only reaction product, generated through the hydrogenation of the Nitro group of dimethylnitrobenzene. The effects of hydrogen partial pressure, catalyst loading, dimethylnitrobenzene concentration and temperature on the reaction conversion have been reported. Near first-order dependence on dimethylnitrobenzene concentration and hydrogen pressure were observed for the initial rate of dimethyl-nitrobenzene hydrogenation over the 5% Pd/C catalyst. Furthermore, an increase in the catalytic activity as the reaction temperature, pressure and weight of catalysts was observed. Conventional Arrhenius behavior was exhibited by the catalyst, Pd/C showed activation energies of 614 J/mol.