This paper deals with the three-phase catalytic hydrogenation kinetics of adiponitrile on Raney nickel. It has been stated that the surface reaction is the limiting step, and that hydrogen is being dissociated at the catalyst surface. The Langmuir-Hinshelwood kinetic formalism seems to be the most appropriate model to fit the experimental data. The major difficulty relative to model discrimination based on the Langmuir-Hinshelwood hypothesis concerns the types of catalytic sites involved : a single site according to competitive adsorption or two catalytic sites corresponding respectively to hydrogen and nitrile. Compared to initial kinetics, complete kinetics provide much more information and this is the main reason why they generate more accurate laws. This accuracy permits significant discrimination between the two models for the catalytic sites, a distinction not achieved by any other means. A complementary analysis of parameter estimation and significance reveals an incomplete determination of the adsorption constants, which can only be optimized through their ratios. Also discussed are other significant effects on the hydrogenation kinetics, such as the role of the solvent and evidence of interactions between species, with a view to future possible Langmuir-Hinshelwood modeling in the liquid phase.