Hydrogenation of p-Chloronitrobenzene over Nanostructured-Carbon-Supported Ruthenium Catalysts

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) have been used for the first time to support ruthenium nanoparticles for the hydrogenation of p‐chloronitrobenzene (p‐CNB) to produce selectively p‐chloroaniline. The preparation of well‐dispersed ruthenium catalysts from the [Ru3(CO)12] precursor required activation of the purified supports by nitric acid oxidation. The supports, purified and functionalized, and the supported catalysts have been characterized by a range of techniques. The catalytic activity of these materials for the hydrogenation of p‐CNB at 35 bar and 60 °C is shown to reach as high as 18 molp‐CNB gRu−1 h−1, which is one order of magnitude higher than a commercial Ru/Al2O3 catalyst. Selectivities between 92 and 94 % are systematically obtained, the major byproduct being aniline. Carbon nanotubes and carbon nanofibers act as supports for ruthenium nanoparticles in the hydrogenation of p‐chloronitrobenzene to selectively produce p‐chloroaniline. The preparation of well‐dispersed ruthenium catalysts from a [Ru3(CO)12] precursor requires activation of the purified supports by nitric acid oxidation. The catalytic activity is one order of magnitude higher than that of a commercial Ru/Al2O3 catalyst.