26 research outputs found
Bimetallic PdZn nanoparticles for the selective hydrogenation of acetylenic alcohols
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Bimetallic PdZn nanoparticles for the selective hydrogenation of acetylenic alcohols
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A kinetic study of the liquid-phase hydrogenation of citral on Au/TiO2 and Pt-Sn/TiO2 thin films in capillary microreactors
No full textThe kinetics of the liquid-phase hydrogenation of citral (3,7-dimethyl-2,6-octadienal) on Au/TiO2 and Pt–Sn/TiO2 thin films was studied in the temperature range 313–353 K and citral concentrations of 0.25–10.0 mol m-3. The thin films were deposited onto the inner walls of silica capillaries with internal diameter of 250 µm. First-order dependence on hydrogen pressure and near zero order dependence on citral concentration were observed for the initial rate of citral hydrogenation over the Pt–Sn/TiO2 and Au/TiO2 thin films. The Au/TiO2 catalyst prevents citronellal formation. The highest yield of unsaturated alcohols was obtained on the Pt–Sn/TiO2 film at a reaction temperature of 343 K, liquid residence time of 30 min and a citral conversion of 99%
Nanoparticulate copper - Routes towards oxidative stability
No full textA modified polyol-based reduction method in ethylene glycol that incorporates poly(N-vinylpyrrolidone) (PVP, Mav = 10000; 40000; 55000) as polymeric anti-agglomerant alongside a reducing additive (N2H4·H2O, NaBH4, NaH2PO2·H2O) has been employed to investigate the influence of synthetic parameters on the purity, morphology and stability of an array of polymer-coated copper nanoparticles. While data point to ethylene glycol being capable of acting as a reductant in this system, the use of NaH2PO2·H2O as co-reductant in tandem with the presence of PVP (Mav 40000) has rendered nanoparticles with a mean size distribution of 9.6 ± 1.0 nm that exhibit stability towards oxidation for several months. These data allow us to probe fundamentally how oxidatively stable nano-copper might be achieved
Thin catalytic coatings on microreactor walls A way to make industrial processes more efficient
No full textCurrent trends in the development of microstructured reactors with thin catalytic films (from 100 nm up to several microns) that have self-assembled nanostructures are discussed. A major technique that is used to prepare such films is sol-gel processing. This involves depositing a complex fluid on a microstructured substrate by dip, spin, or spray coating, followed by surfactant removal to form the porous nanostructures. A novel methodology has been developed by which a uniform coating containing controlled amounts of (poly)metallic nanoparticles can be obtained. This elegant strategy is based on the condensation of metal oxide species by self-assembly in the presence of metallic colloids. The potential microreactor applications brought forth by this innovative protocol are placed in perspective in the light of its versatility
Wall coated capillary microreactors with confined metallic nanoparticles for chemicals synthesis
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