Yuan

Hydrodeoxygenation of Lignin-Derived Phenols into Alkanes by Using Nanoparticle Catalysts Combined with Brønsted Acidic Ionic Liquids**

The transformation of lignin-derived phenolic compds. to alkanes was achieved using catalysts based on Bronsted acidic ionic liqs. (ILs). The catalytic system is composed of metal nanoparticles (NPs) and a functionalized Bronsted acidic IL immobilized in a nonfunctionalized IL, allowing hydrogenation and dehydration reactions to occur in tandem. Compared to previous systems that are either performed with metal sulfite or with mineral acid/ supported metal catalysts in water, this system allows lignin derivs. to be upgraded in an efficient and less energy-demanding process.

Development of Palladium Surface-Enriched Heteronuclear Au-Pd Nanoparticle Dehalogenation Catalysts in an Ionic Liquid

Heteronuclear Au-Pd nanoparticles were prepared and immobilized in the functionalized ionic liquid [C(2)OHmim][NTf(2)]. The structural and electronic properties of the nanoparticles were characterized by a range of techniques and the surface of the nanoparticles was found to be enriched in Pd. Moreover, the extent of Pd enrichment is easily controlled by varying the ratio of Au and Pd salts used in the synthesis. The heteronuclear nanoparticles were found to be effective catalysts in dehalogenation reactions with no activity observed for the pure Au nanoparticles and only limited activity for the pure Pd nanoparticles. The activity of the heteronuclear nanoparticles may be attributed to charge transfer from Pd to Au and consequently to more efficient reductive elimination.

Rhodium nanoparticle catalysts stabilized with a polymer that enhances stability without compromising activity

Rh NPs coated with a PVP-derived polymer, that combines several distinct protective interactions, exhibit superior thermal and catalytic stability compared to analogue NPs coated with PVP.

Nanometallic chemistry: deciphering nanoparticle catalysis from the perspective of organometallic chemistry and homogeneous catalysis

Nanoparticle (NP) catalysis is traditionally viewed as a sub-section of heterogeneous catalysis. However, certain properties of NP catalysts, especially NPs dispersed in solvents, indicate that there could be benefits from viewing them from the perspective of homogeneous catalysis. By applying the fundamental approaches and concepts routinely used in homogeneous catalysis to NP catalysts it should be possible to rationally design new nanocatalysts with superior properties to those currently in use.

pH-Sensitive gold nanoparticle catalysts for the aerobic oxidation of alcohols.

Gold nanoparticles (NPs) stabilized by carboxylate modified polyvinylpyrrolidone have been prepared and fully characterized. The gold NPs efficiently catalyze the aerobic oxidation of benzyl alcohol in water at ambient temperature and are easily separated from the reaction mixture by lowering the pH of the solution, causing the NPs to precipitate. The mechanism of the precipitation process has been studied. Due to the efficiency of this process, the NPs may be reused as catalysts by readjusting their pH.

Ag–Pd and CuO–Pd nanoparticles in a hydroxyl-group functionalized ionic liquid: synthesis, characterization and catalytic performance

Heteronuclear Ag–Pd and CuO–Pd nanoparticles with a controllable Ag : Pd or Cu : Pd ratio were easily synthesized through thermal decomposition of their acetate salts in a functionalized ionic liquid, [C2OHmim][NTf2]. The structural and electronic properties of these particles were characterized by ICP-OES, TEM, XRD and XPS techniques. The Ag–Pd nanoparticles have a silver enriched core covered by a Pd enriched shell. The addition of Ag clearly enhanced the catalytic activity of Pd in the hydrogenation of –NO2 and –CC– functionalities. Interestingly, in the CuO–Pd nanoparticles, Pd tends to stay in the inner part of the particle, leaving the outer layer rich in CuO, which exhibits less activity than Pd NPs.

Rational Design of a Molecular Nanocatalyst‐Stabilizer that Enhances both Catalytic Activity and Nanoparticle Stability

Keywords: catalyst stability ; catalytic activity ; hydrogenation ; nanoparticles ; stabilizers Reference EPFL-ARTICLE-184053doi:10.1002/cctc.201200552View record in Web of Science Record created on 2013-02-27, modified on 2017-12-03

Rapid nanoparticle-catalyzed hydrogenations in triphasic millireactors with facile catalyst recovery

We report a triphasic segmented flow millireactor for rapid nanoparticle-catalyzed gas–liquid reactions with facile catalyst recovery. Process intensification using a pseudo-biphasic scheme of reactor operation allows order-of-magnitude reduction in reaction times for a variety of substrates and catalysts.

Triphasic Segmented Flow Millireactors for Rapid Nanoparticle-Catalyzed Gas–Liquid Reactions — Hydrodynamic Studies and Reactor Modeling

In this paper, we present detailed experimental and modeling studies of a recently developed triphasic segmented flow millireactors for rapid nanoparticle-catalyzed gas-liquid reactions. We first present detailed observations of the hydrodynamics and flow regimes in a pseudo-biphasic mode of operation, which enable the design and selection of optimal operating conditions for the triphasic millireactor. We particularly focus on and analyze the presence of wetting films of the organic phase on the reactor walls at high flow speeds, a consequence of the phenomenon of forced wetting, which is a key ingredient for optimal reactor performance. Next, we describe the development of a simple phenomenological model, incorporating the key mass transport steps that accurately captures the observed experimental trends for the rhodium nanoparticle (RhNP) catalyzed hydrogenation of a model substrate (1-hexene). We further discuss and analyze the consequences of this model.