Selective Reduction of Nitroarenes Catalyzed by In-Situ Generated Nanoscale Hematite

It is interesting and important to develop cost-effective and highly efficient method for the selective reduction of nitroarenes to produce the widely applied anilines. The catalytic reaction directly driven by metal salts during which the real active species would formed is a convenient way, but the detailed mechanism need further investigation. In this work, the performance of different metal salts were studied, and it showed that iron salts were much more promising to serve as catalyst precursor. Moreover, the reaction was remarkably affected by the type of anion. The addition of other salts to the iron salts mediated system had negative effect on the reaction. In-depth study suggested that the in-situ generated hematite (alpha-Fe2O3) nanoparticles were the real active species. Small and uniform alpha-Fe2O3 nanoparticles could be formed when the reaction was carried out at relatively low temperature, while the generated nanoparticles were much larger when performed at higher temperature. Under otherwise identical conditions, the in-situ formed alpha-Fe2O3 also outperformed many other commercial benchmark catalysts. [GRAPHICS] .

Automated summary

This study developed a cost-effective and efficient method for the selective reduction of nitroarenes and investigated the influence of metal salts on the reaction. It was found that iron salts showed more promising performance as catalyst precursors. Additionally, in-situ generated α-Fe2O3 nanoparticles were identified as the real active species.