Selective hydrogenation of aromatic compounds using modified iridium nanoparticles

Abstract

Till now, Ionic liquid-stabilized metal nanoparticles were investigated as catalytic materials, mostly in the hydrogenation of simple substrates like olefins or arenes. The adjustable hydrogenation products of aromatic compounds, including quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes, are always of special interest, since they provide more choices for additional derivatization. Iridium nanoparticles (Ir NPs) were synthesized by the H 2 reduction in imidazolium ionic liquid. TEM indicated that the Ir NPs is worm-like shape with the diameter around 12.2 nm and IR confirmed the modification of phosphine-functionalized ionic liquids (PFILs) to the Ir NPs. With the variation of the modifier, solvent and reaction temperature, substrate like quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes could be hydrogenated by Ir NPs with interesting adjustable catalytic activity and chemoselectivity.Ir NPs modified by PFILs are simple and efficient catalysts in challenging chemoselective hydrogenation of quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes. The activity and chemoselectivity of the Ir NPs could be obviously impacted or adjusted by altering the modifier, solvent and reaction temperature.

Visible‐Light Driven Ni‐Incorporated CdS Photocatalytic Activities for Azo‐Bond Cleavages with Hydrogenation Reaction

“…The first step is to nitrate benzene with concentrated nitric acid and sulfuric acid to produce nitrobenzene (NB) at ∼60 °C, followed by a hydrogenation reaction at ∼300 °C [9] . Other synthesis procedures of aniline from NB can also be done at 90–125 °C under high pressure of hydrogen [10] or H 2 pressure at 3 MPa in ionic liquid [11] or at room temperature with electrocatalysis [12] . On the other way, NB also can be chemically converted to aniline over Bi 2 MoO 6 with ammonium oxalate as a reducing agent or over g‐C 3 N 4 with hydrazine in 80 °C water [11,13] .…”

“…Other synthesis procedures of aniline from NB can also be done at 90–125 °C under high pressure of hydrogen [10] or H 2 pressure at 3 MPa in ionic liquid [11] or at room temperature with electrocatalysis [12] . On the other way, NB also can be chemically converted to aniline over Bi 2 MoO 6 with ammonium oxalate as a reducing agent or over g‐C 3 N 4 with hydrazine in 80 °C water [11,13] . Furthermore, the 4‐NP‐to‐4‐AP conversion in a mild condition also needs a strong reducing agent to provide hydrogen ions.…”

“…[12] On the other way, NB also can be chemically converted to aniline over Bi 2 MoO 6 with ammonium oxalate as a reducing agent or over g-C 3 N 4 with hydrazine in 80°C water. [11,13] Furthermore, the 4-NP-to-4-AP conversion in a mild condition also needs a strong reducing agent to provide hydrogen ions.…”

Sustainable and recyclable palladium nanoparticles–catalyzed reduction of nitroaromatics in water/glycerol at room temperature

“…From the viewpoint of reaction post-processing, the direct hydrogenation of nitroarenes using H 2 is be more favorable, because it makes the reaction cleaner, and makes purification of the products and recovery of the catalysts easier. [19][20][21][22] H 2 has gained wide application in the hydrogenation of nitroaromatics but it usually needs high temperatures and high pressure equipment, and also poses safety issues. Hence, it is a great challenge to develop valuable catalysts with high catalytic Sustainable and recyclable palladium nanoparticles-catalyzed reduction of nitroaromatics in water/glycerol at room temperature efficiency, excellent chemoselectivity and reusability for the hydrogenative reduction of nitro groups, and realizing the conversion of nitro-to-amine in the presence of H 2 at ambient temperature and pressure.…”

Enantioselective hydrogenation of α‐ketoesters catalyzed by cinchona alkaloid stabilized Rh nanoparticles in ionic liquid

“…So far, ionic liquid‐stabilized metal nanoparticles have been used as catalysts mainly in the hydrogenation of alkenes or arenes . We previously reported the use of ionic liquid‐stabilized ruthenium nanoparticles to catalyze the tunable chemoselective hydrogenation of aromatic ketones and quinolines . However, the research on the use of Rh nanoparticles for enantioselective hydrogenation in ionic liquids was quite limited by now .…”