Kinetics of the hydrogenation of a mixture of nitrobenzene and azoxybenzene on skeletal nickel in an aqueous solution of propan-2-ol

The sequence of the reduction of nitro and azoxy groups in the combined hydrogenation of nitrobenzene and azoxybenzene on skeletal nickel in an aqueous azeotropic solution of propan-2-ol is considered. The time dependences of the rates and concentrations of the initial compound and reaction product for the hydrogenation of individual compounds (nitrobenzene and azoxybenzene) in the solvent of the indicated composition are discussed for comparative analysis. In all cases, the reactions proceed selectively to aniline without accumulating side products. The reduction of the nitro and azoxy groups involves hydrogen bound by the active sites of the catalyst surface. The competitive character of adsorption between the initial compounds and formed aniline is observed. Nitrobenzene is characterized by the highest adsorbability, whereas azoxybenzene and aniline are less adsorbable.