Selective Hydrogenation of m-Dinitrobenzene to m-Nitroaniline over Ru-SnOx/Al2O3 Catalyst

Abstract

Series catalysts of Ru-SnO x /Al 2 O 3 with varying SnO x loading of 0-3 wt% were prepared, and their catalytic activity and selectivity have been discussed and compared for the selective hydrogenation of m-dinitrobenzene (m-DNB) to m-nitroaniline (m-NAN). The Ru-SnO x /Al 2 O 3 catalysts were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and hydrogen temperature-programmed reduction (H 2 -TPR) and desorption (H 2 -TPD). Under the modification of SnO x , the reaction activity increased obviously, and the best selectivity to m-NAN reached above 97% at the complete conversion of m-DNB. With the increasing of the SnO x loading, the amount of active hydrogen adsorption on the surface of the catalyst increased according to the H 2 -TPD analysis, and the electron transferred from Ru to SnO x species, as determined by XPS, inducing an electron-deficient Ru, which is a benefit for the absorption of the nitro group. Therefore, the reaction rate and product selectivity were greatly enhanced. Moreover, the Ru-SnO x /Al 2 O 3 catalyst presented high stability: it could be recycled four times without any loss in activity and selectivity.

Synthesis of flow‐compatible Ru-Me/Al2O3 catalysts and their application in hydrogenation of 1-iodo-4-nitrobenzene

“…The maximum temperature of the reduction peak was slightly lower than that of Scheme 1 Simplified reaction scheme for hydrogenation of 1-iodo-4nitrobenzene to 4-iodoaniline using molecular hydrogen including side products formed by hydro-deiodination (for detailed reaction mechanism see e.g. ref [38]) bulk RuO 2 [42] and was similar to that obtained for Ru/Al 2 O [43]. This broad peak is mainly attributed to the reduction of oxidized Ru species which are formed on alumina surface during catalyst storage under ambient conditions.…”

“…The amount of hydrogen consumed in the 2nd reduction was generally higher than in the 1st reduction (Table 1 indicates that the interaction between Ru and the promoter in these samples should be stronger compared to the other ones. Moreover, the amount of consumed hydrogen for these catalysts was significantly higher than the theoretical value necessary to reduce RuO 2 to metallic Ru revealing that partially Cu, Sn, or Fe oxide species [43] were also reduced by hydrogen. Reduction of bulk SnO 2 and of SnO 2 particles deposited on alumina occurred at temperatures higher than 600°C [42,45] and reduction of alumina supported Fe 2 O 3 starts at temperatures higher than 400°C [46].…”

Ruthenium on Alkali‐Exfoliated Ti3(Al0.8Sn0.2)C2 MAX Phase Catalyses Reduction of 4‐Nitroaniline with Ammonia Borane

“…However, these signals can be extracted using a similar approach as with Ru 3d and C 1s. Ru 3p are much broader than Ti 2p and there are no Ru signals below 461 eV [88–91] . This means that the Ti 2p signals up to 459 eV can be quantitatively assigned.…”

Continuous-Flow Hydrogenation of D-Xylose with Bimetallic Ruthenium Catalysts on Micrometric Alumina

“…Cheng et al [31] doped a ruthenium catalyst with SnOx and reported an electronic interaction between Ru-SnOx due to an electron transfer from the Ru nanoparticles to SnOx, inducing an electron deficit state of ruthenium nanoparticles, which was favorable for the adsorption of the electropositive N-atom belonging to the reactant nitro group. The electron deficient state of ruthenium can also be favorable for the hydrogen adsorption, resulting in the production of more active hydrogen species.…”