Hydrogenation of Acetophenone in the Presence of Ru Catalysts Supported on Amine Groups Functionalized Polymer

Abstract

Liquid phase hydrogenation of acetophenone (ACT) is studied over ruthenium catalysts (1-4 wt% Ru) supported on gel-type methacrylate-styrene resin (FCN) functionalized with C=O, -NH, and -NH 2 groups. Microscopic studies (SEM, STEM) show that the nature of Ru particles depends on the level of Ru doping. At low Ru content (1-2 wt%) ruthenium nano-clusters are formed, while at 4 wt% Ru, metal crystallites of few nanometers in size are observed. Catalytic reactions are performed at mild conditions (atmospheric pressure of hydrogen, 40°C) in biphasic isooctane-water (IO/H 2 O) solvent system, and, for comparison, in a single component solvent (isooctane or ethanol). The use of biphasic IO/H 2 O solvent system results in a dramatic improvement of selectivity. The hydrogenation of C=O in acetophenone dominates over the hydrogenation of aromatic ring, yielding 1-phenylethanol with ca. 80% selectivity. Ru/FCN catalysts exhibit higher selectivity than the reference Ru/Al 2 O 3 . This is tentatively assigned to the steric effects induced by the polymer network on migrating reactant molecules. Advantageous influence of biphasic IO/H 2 O solvent system has been attributed to the solvation of phenyl ring of acetophenone by non-polar isooctane, which facilitates the interaction with the catalyst surface via carbonyl group and leads to the preferential reduction to 1-phnenylethanol.

Porous hierarchical nickel nanostructures and their application as a magnetically separable catalyst

“…6), indicating the much better anti-oxidation capability than the commonly used RANEYÒ Ni catalyst, which was prepared by a complicated and non-green process. 39 The catalytic performance was better than those of supported Ni, Ni-Pt catalysts (with similar conditions), 29 as well as supported Ru, Pd, Pt noble catalysts (with mild conditions), [24][25][26][27] and was comparable to that of RANEYÒ Ni, 28 which may be associated with its unique nanostructure and relatively large specific surface area of 24.5 m 2 g À1 . The large specific surface area provides more active sites, while the porous hierarchical nanostructures favour mass transfer and reduce transport limitations.…”

“…Although conventional inorganic hydrides could exclusively give a PE product, the toxic residues and the difficulties faced in product separation and catalyst recovery call for heterogeneous catalysts. 24 Great effort has been devoted to exploring recyclable heterocatalysts such as Ru, Pt and Pd, [24][25][26][27] as well as Ni. 28,29 These catalysts are quite efficient, but with high cost or poor anti-oxidation capability.…”

Realizing Catalytic Acetophenone Hydrodeoxygenation with Palladium-Equipped Porous Organic Polymers

“…3 AP hydrogenation is a complex multistep reaction with the competitive hydrogenation of the carbonyl group and aromatic ring and the concurrent hydrogenolysis of PhE, 4 and hence, all of these possible alternatives make it very challenging to selectively synthesize PhE/EB from AP. So far, several catalytic systems based on Pt, 5 Pd, 6 Ru, 7 and Cu 8 have been reported for this selective reaction. However, these catalytic systems present issues associated with harsh reaction conditions like high hydrogen pressures and high temperatures, as well as metal leaching, which are big hurdles for practical applications.…”

NHC-stabilized ruthenium nanoparticles as new catalysts for the hydrogenation of aromatics

“…The chemoselective reduction of aromatic ketones to benzylalcohols can be carried out effectively by direct hydrogenation and hydrogen transfer reactions, both employing homogeneous catalysts, 36 but the selective hydrogenation of the aromatic ring is more complicated. This reaction has been studied in detail, 28,[32][33][34][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] usually producing a mixture of the three products when heterogeneous catalysts are used and the reaction is not complete. The effect of several parameters on acetophenone hydrogenation activity and selectivity was studied.…”