Concurrent Hydrogenation of Aromatic and Nitro Groups over Carbon-Supported Ruthenium Catalysts

Abstract

The concurrent hydrogenation of aromatic and nitro groups poses particular challenges due to the highly differing adsorption strengths of the two chemical moieties on the surfaces of metal catalysts. In a study of the hydrogenation of nitrobenzene as a model reaction, catalysts of ruthenium supported on carbon nanotubes (Ru/CNT) provided an ideal compromise, allowing for hydrogenation of both the aromatic ring and the nitro group. The use of methyl-labeled substrates enabled tracking the pathway of specific substrates and obtaining insight into the relative rates for the hydrogenation of nitrobenzene and intermediates. Together with findings on the coadsorption of nitrobenzene and aniline on the Ru/CNT catalyst, an advanced mechanistic model for the hydrogenation of nitrobenzene emerges.