Chemoselective nitroarene hydrogenation over Ni-Pd alloy supported on TiO₂ prepared from ilmenite-type Pd_xNi_1−xTiO₃

Herein, we prepared TiO₂ (rutile)-supported monometallic Ni and bimetallic Pd-Ni catalysts by thermal reduction of Pd_xNi_{1− x}TiO₃ (x = 0 and 0.045) and evaluated their performance for the chemoselective hydrogenation of nitrobenzene under optimized conditions. In contrast to Ni/TiO₂, Pd-Ni/TiO₂ featured a negligible loss of both conversion and aniline yield over five consecutive catalytic cycles, and instrumental analysis and catalytic activity evaluation revealed that this enhanced stability is due to Pd-Ni-alloy formation. Furthermore, Pd-Ni/TiO₂ was used to prepare aromatic-amines used as building blocks for the production of important drugs precursors, achieving conversions of >98 % and a chemoselectivity of 99 % in the absence of undesired side-reactions.