A Rhodium Nanoparticle–Lewis Acidic Ionic Liquid Catalyst for the Chemoselective Reduction of Heteroarenes

Abstract

We describe a catalytic system composed of rhodium nanoparticles immobilized in a Lewis acidic ionic liquid. The combined system catalyzes the hydrogenation of quinolines, pyridines, benzofurans, and furan to access the corresponding heterocycles, important molecules present in fine chemicals, agrochemicals, and pharmaceuticals. The catalyst is highly selective, acting only on the heteroaromatic ring, and not interfering with other reducible functional groups.

Highly Networked Platinum–Tin Nanowires as Highly Active and Selective Catalysts towards the Semihydrogenation of Unsaturated Aldehydes

“…The selective hydrogenation of α,β‐unsaturated aldehydes has aroused great attention, because it involves significant steps to yield widely used unsaturated alcohols for the synthesis of various fine chemicals, particularly in the field of pharmaceuticals, flavorings, and perfumes . A typical example is the selective hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL), which is a critical process for desired industrial products.…”

Chemoselective reduction of heteroarenes with a reduced graphene oxide supported rhodium nanoparticle catalyst

“…under the same conditions it affords the 1,2,3,4-tetrahydroquinoline product in 74% yield, albeit with equally high selectivity. The yield and selectivity achieved with the Rh NP-rGO catalyst are comparable with those of Rh NPs in Lewis acidic ionic liquids that are sensitive to moisture 50 and N-graphene-modified cobalt nanoparticles (Co 3 O 4 -Co/NGr@α-Al 2 O 3 ) 22 which operate under harsher conditions.…”

Catalytic Ionic‐Liquid Membranes: The Convergence of Ionic‐Liquid Catalysis and Ionic‐Liquid Membrane Separation Technologies

“…The improved selectivity was attributed to differences in the solubility of acetylene, ethylene and ethane in the IL, that is, owing to the low solubility of ethylene in [BMIm][PF 6 ], it is rapidly eliminated from the surface of the catalyst and is not hydrogenated further . Similarly, [BMIm][BF 4 ]‐stabilised rhodium NPs containing a Lewis acidic anion selectively hydrogenated heteroarenes over other aromatics, aldehydes, esters and other functional groups . The heteroatom is believed to coordinate to the Lewis acid, which activates the heteroarene C=C double bonds.…”