Catalytic hydrogenation of dimethyl-nitrobenzene to Dimethyl-aniline over Ni catalysts

The catalytic transfer hydrogenation of dimethyl-nitrobenzene (DN) to Dimethyl-aniline (DA) was studied in the temperature range 343–403 K  , pressure range of 4–10 bar H2 and ethanol as solvent using Ni on alumina-silicate 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 dimethyl nitrobenzene. Dimethyl-aniline was the only reaction product, generated through the hydrogenation of the Nitro group of dimethyl-nitrobenzene. The effects of hydrogen partial pressure, catalyst loading, dimethyl-nitrobenzene concentration and temperature on the reaction conversion have been reported. Near first-order dependence on dimethyl-nitrobenzene concentration and hydrogen pressure were observed for the initial rate of dimethyl-nitrobenzene hydrogenation over the Ni 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 catalyst, Ni showed activation energies of 808 J/mol.

Keywords:

Liquid-phase hydrogenation , Ni catalysts , dimethyl-nitrobenzene , dimethyl-aniline , operation condition