Gold nanoparticles supported on P25 titania (Au/TiO2) exhibit photocatalytic activity for UV and visible light (532 nm laser or polychromatic λ > 400 nm) water splitting. The efficiency operating mechanism are different depending whether excitation occurs the semiconductor (gold acting as electron buffer site gas generation) surface plasmon band of gold (photoinjection electrons from onto conduction less oxidizing hole potential about −1.14 V). For novel photoactivity Au/TiO2, it has been...

By a combination of kinetic and theoretical studies it is concluded that gold intrinsically active to perform the Sonogashira coupling reaction between phenylacetylene iodobenzene. The presence Pd impurities not mandatory for catalyst activity.

In contrast to gamma-Al(2)O(3), TiO(2), ZrO(2), MgO and Y(2)O(3), CeO(2) is a reusable catalyst for the reaction of CO(2) with omega-aminoalcohols form cyclic carbamates; highest yield (68%) was obtained preparation N-alkyl 1,3-oxazolidin-2-ones from ethanolamines.

Inelastic neutron scattering of gold nanoparticles (3–4 nm, 0.48 wt%) supported on nanoparticulate ceria (5 nm) (Au/CeO2) shows that hydrogen treatment Au/CeO2 gives rise to the appearance a new band (400–600 cm−1) corresponding bridging hydroxyl groups. This disappears (without observing any band) when sample is exposed CO2 or O2. FT-IR spectroscopy same samples formation Au–H after chemisorption. The also subsequently treated with In last case hydroperoxide observed. assignments were by...

A series of metal oxide nanoparticles with acid or basic properties exhibit low to moderate activity towards the transalkylation propylene carbonate methanol; deposition gold on nanoparticulated ceria significantly increases this transalkylation.

The nature of the active sites involved in gold catalyzed Sonogashira cross-coupling reaction between iodobenzene and phenylacetylene, competitive homocoupling reactions, has been investigated by means DFT calculations, kinetic measurements, synthesis catalysts with different surface species. Several catalyst models have theoretically to simulate nanoparticles size either isolated, supported on inert materials, or CeO2. mechanistic studies show that IB dissociation occurs low coordinated Au0...

Golden catalyst: In a two-step one-pot catalytic process gold nanoparticles supported on CeO2 are able to convert nitroaromatics into aromatic carbamates, thereby providing an alternative phosgene-free route towards polyurethanes (see figure). Detailed facts of importance specialist readers published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by the authors. Please note: The publisher is responsible for content...

H-Au-np/CeO2 species, that are important intermediates in the alcohol oxidation by gold nanoparticles, show a photoinduced reactivity. UV-visible photoexcitation deaerated conditions causes hydride transfer from to spin trap DMPO. The photoassisted breaking of Au–H bond restores catalyst its active form. As consequence, photochemical excitation has positive effect on catalytic 2-pentanol under anaerobic conditions, demonstrating light can be used place oxygen. This new photocatalytic...

Four nitrogen-containing organic compounds [1,5,7-triazabicyclo(4,4,0)dec-5-ene, 4-(N,N-dimethylamino)pyridine, N-methylimidazole, and l-proline] have been tested as organocatalysts for the reaction of dimethyl carbonate with an aromatic diamine, 2,4-diaminotoluene (DAT). Although, generally, N-methylation was predominant process, variable proportions N-carbamoylation were also observed. Reaction kinetics indicates that are independent parallel processes. DAT conversion increases temperature...

Gold statt Phosgen: Ein zweistufiger Eintopfprozess an Goldnanopartikeln auf CeO2 als Katalysator wandelt Nitroarene in aromatische Carbamate um. Das Verfahren stellt eine phosgenfreie Alternative für die Synthese aromatischer Polyurethane dar. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by the authors. Please note: The publisher is responsible for...

When exposed to high surface temperatures, engine lubricating oils degrade and may form solid deposits, which cause operational issues increase shutdown time maintenance costs. Despite its being a common issue in operation, the information available on mechanics of this phenomenon is still lacking, experimental data conditions must be updated match improvements both lubricant stability efficiency. To end, an apparatus has been developed study mechanisms that lead degradation deposit...

Abstract Operational, efficiency, safety, and economic issues may arise from the formation accumulation of sludge, varnish, coke deposits that result degradation engine lubricants through oxidation or thermal breakdown processes. Having a good understanding limits lubricant performance be useful in determining best way to protect engines. To this end, experiments were conducted using Mobil DTE 732, turbine lubricant, is aerated coarse gas dispersion tube. The oil then flows heated test...

Aliphatic amines react sluggishly with dimethyl carbonate (DMC) to give a mixture of N-methylation and carbamoylation. Nanoparticulated ceria as catalyst increases, in general, conversion selectivity toward This increase catalytic activity carbamoylation is even increased by deposition Au nanoparticles on ceria. However, contrast aromatic for which complete using ceria-supported can be achieved, the aliphatic occurs only moderate selectivity.

Abstract When exposed to excessively high temperatures, the lubricating oils in turbines undergo extreme oxidation and thermal degradation processes that eventually result formation of solid deposits can, turn, cause operational problems. This work describes testing characterization process a newly constructed test rig studies propensity lubricants form such deposits. In rig, lubricant flows through heated tube, thermally degrades or oxidizes, forms adhere surface. An oil flow rate...

Over the last several decades, turbine efficiency has improved significantly, resulting in higher operating temperatures that negatively affect lubricating oil circulating through system. Exposure to high results degradation and eventual formation of solid deposits which greatly limit oil’s ability reduce wear cool components. An experimental apparatus was designed built allow for studying better understanding this phenomenon. The consists a flow loop with heated test section is pumped....

Abstract When exposed to extremely high temperatures, oils in turbomachinery applications can degrade until they form solid, carbonaceous coke deposits that cause serious operational issues. Three of the main factors affect formation process are temperature, residence time, and oil composition (basestock additives). This study explored effect surface temperature on coking induction time four turbine oils. The is defined as amount required for start forming accumulating under specific test...

Turbine oils often encounter high surface temperatures during operation that cause their breakdown and the formation of solid, carbonaceous coke deposits. These deposits may serious operational problems, delays, loss revenue. Recognizing changes in a lubricant’s composition as it undergoes high-temperature break down reactions allow better lubrication maintenance practices to be implemented. Fourier Transform Infrared (FTIR) spectroscopy is listed way detect oil composition. This study...

Abstract Lubricants experience harsh conditions which result in degradation of the oil. To imitate similar conditions, Mobil DTE 732, a common gas turbine lubricating oil, was subjected to high temperatures for an extended period time, until thermal occurred, indicated through creation coke. Samples were taken throughout this process, with sample that tested having been exposed 78 h. Utilizing endwall injector system, samples ignited behind reflected shock waves high-pressure tube (HPST) at...