Nickel sulfide nanoparticles on alumina and unsupported for p-chloroaniline production

Due to the need for producing intermediate chemicals such as p-chloroaniline (p-CA) using more environmentally friendly and efficient processes, nanostructured nickel and nickel sulfide-based catalysts were synthesized and studied. The selective p-chloronitrobenzene (p-CNB) gas-phase hydrogenation to produce p-CA was tested. The catalysts were characterized by N₂ physisorption (S_BET), temperature-programmed reduction (TPR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalytic activity was evaluated in terms of conversion and selectivity towards p-CNB and p-CA, respectively. Based on the experimental results, the addition of sulfur promoted the selectivity towards p-CA in a range of temperature from 120 to 220 ºC. The selectivity towards p-CA was close to 100 %, avoiding the formation of undesirable side products. Therefore, it is suggested that sulfured-Ni based catalysts increase the surface acidity, which allowed improved hydrogenolysis of the N-O bond.