Kinetic study of the hydrogenation of p-nitrophenol to p-aminophenol over micro-aggregates of nano-Ni2B catalyst particles

The present work concerns a thorough investigation of the performance of a nano-nickel boride catalyst for the direct hydrogenation of p-nitrophenol (PNP) to p-aminophenol (PAP) in a batch slurry reactor using ethanol as solvent. The effect of pH during the synthesis procedure on the properties of the as-synthesized catalyst has been investigated using FTIR, XRD, ICP and FESEM analysis. The synthesized catalyst shows a better activity with respect to Raney nickel. The effect of catalyst preparatory method on its activity has been investigated. The effect of reaction temperature (40–80 °C), PNP initial concentration (0.07–0.28 g mL−1) and initial pressure (25–40 bar) on the reaction kinetics has been investigated. It has been shown that the kinetic behavior throughout the whole time domain could be reasonably predicted considering a single site mechanism with atomically adsorbed hydrogen and PNP adsorption as the controlling step.

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► A nano-particle Ni2B catalyst has been synthesized under various conditions.
► Its performance for a direct hydrogenation reaction has been investigated.
► The reaction is the transformation of p-nitrophenol to p-aminophenol by hydrogen.
► The catalyst shows a better activity with respect to Raney nickel.
► The reaction mechanism has been determined.