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 [Ru 3 (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 mol p ‐CNB  g Ru −1  h −1 , which is one order of magnitude higher than a commercial Ru/Al 2 O 3 catalyst. Selectivities between 92 and 94 % are systematically obtained, the major byproduct being aniline.