Nanocatalysts based on Ni nanoparticles in functionalized ionic liquids for chemoselective hydrogenation and transfer hydrogenation of α,β‐unsaturated carbonyl compounds

For the development of catalytically active and selective Ni nanoparticle (NP) catalysts both the choice of the synthesis method and the selection of stabilizer are key parameters. A series of Ni NPs were synthesized in various ionic liquids (Ni/ILs) and applied as catalysts for the chemoselective reduction of 2‐cyclohexen‐1‐one (1), as a representative of the group of α,β‐unsaturated carbonyl compounds with industrial relevance. The Ni/ILs systems were found to be efficient catalysts for the selective hydrogenation of 1 to cyclohexanone (2) under quite mild reaction conditions (130‐170°C, 10 bar H2, 1/Ni molar ratio of 100/1), achieving high conversions in a short reaction time (1 h). The oxidized counterparts (Ni‐NiO/ILs) showed to be active for the selective catalytic transfer hydrogenation (CTH) of 1 to 2‐cyclohexen‐1‐ol (3) with 2‐propanol, also under mild reaction conditions (150 °C, 48 h, 1/Ni ratio of 50/1).