Abstract: A series of titania-supported nickel catalysts with different Ni loadings (10%～40%) were prepared by the incipient impregnation method and applied in the hydrogenation of o-chloronitrobenzene to o-chloroaniline. The effects of nickel loading on the physico-chemical properties of the Ni/TiO2 catalysts were studied by nitrogen adsorption-desorption, X-ray diffraction, temperature-programmed reduction, transmission electron microscopy, and H2 chemisorption. The catalyst performance for the hydrogenation was evaluated in an autoclave reactor. The results showed that the o-chloronitrobenzene conversion increased with increasing Ni loading of the Ni/TiO2 catalysts. When the Ni loading was higher than 30%, no remarkable difference in catalyst performance was observed. For the catalysts with Ni loadings higher than 20% under the reaction conditions of temperature 343 K, hydrogen pressure 1.0 MPa, and catalyst to o-chloronitrobenzene mass ratio of 1/10, both the o-chloronitrobenzene conversion and the selectivity for o-chloroaniline exceeded 99% within 210 min. Hence, Ni/TiO2 is a promising catalyst for the synthesis of o-chloroaniline. The characterization results suggested that Ni surface area and the strong metal-support interaction were important factors affecting the catalyst performance, whereas there was no distinct relation between the specific surface area and catalytic performance of the catalyst.

Key words: nickel, titania, supported catalyst, o-chloronitrobenzene, catalytic hydrogenation, o-chloroaniline