Hydrogen transfer hydrogenation of nitrobenzene to aniline with Ru(acac)3 as the catalyst

Abstract

Tris(acetylacetonato)ruthenium(III)(Ru(acac)3) was synthesized with RuCl3·nH2O and acetylacetone as raw materials. The structure of Ru(acac)3 was identified by FI-IR, 1H NMR, 13C NMR, and elemental analysis. It was used in the catalytic hydrogen transfer hydrogenation of nitrobenzene with sodium formate as hydrogen donor. The effects of reaction conditions on the process, such as temperature, time, dosage of catalyst, and kinds of hydrogen donor, were investigated. The optimal reaction parameters were determined as follows: 80 °C, 4.0 h, the substrate nitrobenzene 20 mL, sodium formate 27.20 g, Ru(acac)3 0.96 g, the conversion of nitrobenzene is 100.0 %, the yield of aniline and the selectivity to aniline are 96.65 %. The reaction mechanism is proposed and analyzed. It exhibited excellent catalytic properties in the hydrogen transfer hydrogenation of nitrobenzene to aniline.