In Situ Generated Iron Oxide Nanocrystals as Efficient and Selective Catalysts for the Reduction of Nitroarenes using a Continuous Flow Method

Abstract

The best of both worlds: The benefits of homogeneous and heterogeneous nanocatalysis are combined, whereby highly reactive colloidal Fe3O4 nanocrystals are generated in situ that remain in solution long enough to allow the efficient and selective reduction of nitroarenes to anilines in continuous‐flow mode (see scheme). After completion of the reaction, the nanoparticles aggregate and can be recovered by a magnet.

Chemical reaction engineering, process design and scale-up issues at the frontier of synthesis: Flow chemistry

“…Different reducing agents, besides H2 were also 7 proposed, among which hydrazine showed promising due to the formation of N2 as byproduct. Hydrazine was combined with in-situ generated Fe3O4 nanocrystals in flow conditions [46].…”

Noncovalently functionalized carbon nanotubes immobilized Fe–Bi bimetallic oxides as a heterogeneous nanocatalyst for reduction of nitroaromatics

“…It is believed that the gross market value of anilines will sharply increase to £10.17 billion by 2020 [6]. Traditional non-catalytic methods that use Fe/HCl system or metal sulfides which inevitably produced large amounts of environment-hazardous wastes and need great energy consumption [7]. In the past decades, many works have been devoted to develop more efficient and sustainable catalysts to promote the conversion of nitroarenes into anilines [8] with different hydrogen sources, such as sodium borohydride [9], silanes [10], boranes [11], formic acid [12], hydrogen [13] and hydrazine [14].…”

Chemo‐selective reduction of nitro and nitrile compounds using Ni nanoparticles immobilized on hyperbranched polymer‐functionalized magnetic nanoparticles

“…Ni, Co, Fe and Cu metals or oxides). [47][48][49][50][51][52] To take advantage of these characteristics and also as a part of our ongoing research programme on the design of new catalysts for the development of useful and green synthetic methodologies, [15,16,[53][54][55][56][57][58][59] herein, we report a dendritic magnetic catalyst based on Ni(0) nanoparticles, an inexpensive non-noble metal, for selective hydrogenation of nitro and nitrile compounds in the presence of various reducible substituents such as carboxylic acid, ketone, aldehyde and halogen to the respective amines using NaBH 4 as the reducing agent in the aqueous phase. …”