Gas Phase Hydrogenation of m-Dinitrobenzene over Alumina Supported Au and Au–Ni Alloy

Abstract

We report, for the first time, 100% selectivity in the continuous gas phase hydrogenation of m-dinitrobenzene to m-nitroaniline (m-NAN) over Au/Al 2 O 3 . The synthesis and application of an alumina supported Au-Ni alloy is also described where alloy formation is demonstrated by XRD, diffuse reflectance UV-Vis and HRTEM analyses. Under the same reaction conditions, Au/Al 2 O 3 delivered a higher (by close to an order of magnitude) hydrogenation rate compared with the alloy. Au-Ni/Al 2 O 3 promoted the formation of both m-NAN and m-phenylenediamine, i.e. partial and complete hydrogenation: the results are consistent with a stepwise reduction mechanism.

Influence of ni addition to a low-loaded palladium catalyst on the selective hydrogenation of 1-heptyne

“…600 K that can be attribu- ted to NiO species with a weak metal-support interaction. [35][36][37][38][39] It is well known that nickel monometallic catalysts prepared from nitrate salts are reduced at temperatures between 600 to 1000 K when the contact between NiO and alumina is intimate. 6,36,38,39 The patterns of reduction depend on the nature of the metal-support interactions, which can be modified by the calcination temperature employed during the preparation of the monometallic nickel catalysts.…”

Exclusive Production of Chloroaniline from Chloronitrobenzene over Au/TiO2 and Au/Al2O3

“…We recently reported an exclusive conversion of p-CNB to p-CAN for continuous gas-phase reaction over Au/Al 2 O 3 . [37] Given the cases cited above, which establish the role that the metal-support can play in Au catalysis, we have extended that work to consider Au/TiO 2 and report herein the results of a comparative study. Our results provide the basis for a sustainable high-throughput production of haloamines under mild conditions.…”

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

“…Over Pd/C and Pt/C catalysts, the reaction condition has significant effects on the product selectivity. Supported Au catalysts, such as Au/Al 2 O 3 , Au/Fe 2 O 3 and Au/TiO 2 , could deliver 100% selectivity to m-NAN at about a 10% conversion of m-DNB [7][8][9][10]; however, the highest selectivity to m-NAN could not achieve 90% after conversion reached above 70%, due to m-NAN being further hydrogenated to m-PDA [5,8,11]. Ru/C was found to be efficient in the selective partial hydrogenation of o-, m-and p-DNBs, and the selectivities to the corresponding NANs achieved over 95% [3].…”