Catalytic hydrogenation of 4-(hydroxyamino)-2-nitrotoluene and 2,4-nitroaminotoluene isomers: Kinetics and reactivity

The kinetics of the liquid-phase hydrogenation of 4-(hydroxyamino)-2-nitrotoluene, 4-amino-2-nitrotoluene, and 2-amino-4-nitrotoluene were studied in ethanol over a 5% Pd/C catalyst, in the temperature range between 283 and 323 K and at a pressure of 0.1. MPa. The reaction rates have been described by a Langmuir-Hinshelwood type model with adsorption of the organic species and hydrogen on a different type of active site. The rate constant, the adsorption constants, and the activation energy for each reaction have been determined by a nonlinear regression analysis. The effect of molecular structure on the reactivity of mono- and dinitro derivatives has been also investigated.