Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol: Effect of Gold Particle Size on Activity and Selectivity in Different Solvents

In the heterogeneous catalyst i-Pd(OAc)2(TPPTS)2, Pd(II) was reduced to Pd(0) by using different alcohol solvents, and the catalyst’s activity was studied in the aerobic oxidation of benzyl alcohol. We studied the effects of the impregnation time in ethanol as a solvent and the use of various alcoholic solvents on the size of palladium nanoparticles. We found that the reduction of palladium by the various alcohols yielded palladium nanoparticles that were active in the aerobic oxidation of benzyl alcohol. As determined by DLS, TEM, and zeta potential analyses, both the impregnation time in ethanol and the type of alcohol used were observed to affect nanoparticle formation, particle size distribution, and agglomeration, as well as the conversion rate. The palladium nanoparticles’ hydrodynamic diameter sizes obtained during the 24 h of impregnation time were in the range of 10–200 nm. However, following 24 h of impregnation in ethanol the nanoparticles tended to form aggregates. The conversion rates of all the primary alcohols were similar, while for secondary alcohol, in which the hydrogen of the hydroxyl is less acidic and there is steric hindrance, the conversion was the lowest. Performing the oxidation using the solvent 1-propanol yielded smaller nanoparticles with narrower distributions in comparison to the reaction that was observed when using the ethanol solvent. On the other hand, the relatively high particle size distribution in 1-hexanol yielded agglomerates.

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Influence of support surface basicity and gold particle size on catalytic activity of Au/γ-AlOOH and Au/γ-Al2O3 catalyst in aerobic oxidation of α,ω-diols to lactones

Applied Catalysis B Environmental ◽

10.1016/j.apcatb.2011.01.041 ◽

2011 ◽

Vol 103 (3-4) ◽

pp. 343-350 ◽

Cited By ~ 27

Author(s):

Jie Huang ◽

Ying Wang ◽

Jiaming Zheng ◽

Wei-Lin Dai ◽

Kangnian Fan

Keyword(s):

Particle Size ◽

Catalytic Activity ◽

Gold Particle ◽

Aerobic Oxidation ◽

Support Surface ◽

Gold Particle Size ◽

Surface Basicity ◽

Al2o3 Catalyst

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Laser Superficial Fusion of Gold Nanoparticles with PEEK Polymer for Cardiovascular Application

Materials ◽

10.3390/ma14040971 ◽

2021 ◽

Vol 14 (4) ◽

pp. 971

Author(s):

Oktawian Bialas ◽

Mateusz Lis ◽

Anna Woźniak ◽

Marcin Adamiak

Keyword(s):

Particle Size ◽

Laser Beam ◽

Gold Particle ◽

Laser Power ◽

Biomedical Application ◽

Parameters Optimization ◽

Size Reduction ◽

Particle Size Reduction ◽

Nano Gold ◽

Gold Particle Size

This paper analyses the possibility of obtaining surface-infused nano gold particles with the polyether ether ketone (PEEK) using picosecond laser treatment. To fuse particles into polymer, the raw surface of PEEK was sputtered with 99.99% Au and micromachined by an A-355 laser device for gold particle size reduction. Biomimetic pattern and parameters optimization were key properties of the design for biomedical application. The structures were investigated by employing surface topography in the presence of micron and sub-micron features. The energy of the laser beam stating the presence of polymer bond thermalisation with remelting due to high temperature was also taken into the account. The process was suited to avoid intensive surface modification that could compromise the mechanical properties of fragile cardiovascular devices. The initial material analysis was conducted by power–depth dependence using confocal microscopy. The evaluation of gold particle size reduction was performed with scanning electron microscopy (SEM), secondary electron (SE) and quadrant backscatter electron detector (QBSD) and energy dispersive spectroscopy (EDS) analysis. The visibility of the constituted coating was checked by a commercial grade X-ray that is commonly used in hospitals. Attempts to reduce deposited gold coating to the size of Au nanoparticles (Au NPs) and to fuse them into the groove using a laser beam have been successfully completed. The relationship between the laser power and the characteristics of the particles remaining in the laser irradiation area has been established. A significant increase in quantity was achieved using laser power with a minimum power of 15 mW. The obtained results allowed for the continuation of the pilot study for augmented research and material properties analysis.

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On the selective aerobic oxidation of benzyl alcohol with Pd/Au-nanoparticles in batch and flow

Nanotechnology Reviews ◽

10.1515/ntrev-2012-0085 ◽

2014 ◽

Vol 3 (1) ◽

pp. 99-110 ◽

Cited By ~ 2

Author(s):

Hannes Alex ◽

Norbert Steinfeldt ◽

Klaus Jähnisch ◽

Matthias Bauer ◽

Sandra Hübner

Keyword(s):

Catalytic Activity ◽

Benzyl Alcohol ◽

Aerobic Oxidation ◽

X Ray ◽

X Ray Scattering ◽

Oxidation Of Benzyl Alcohol ◽

Transmission Electron ◽

Vis Spectroscopy ◽

Selective Aerobic Oxidation

AbstractNanoparticles (NP) have specific catalytic properties, which are influenced by parameters like their size, shape, or composition. Bimetallic NPs, composed of two metal elements can show an improved catalytic activity compared to the monometallic NPs. We, herein, report on the selective aerobic oxidation of benzyl alcohol catalyzed by unsupported Pd/Au and Pd NPs at atmospheric pressure. NPs of varying compositions were synthesized and characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The NPs were tested in the model reaction regarding their catalytic activity, stability, and recyclability in batch and continuous procedure. Additionally, in situ extended X-ray absorption fine structure (EXAFS) measurements were performed in order to get insight in the process during NP catalysis.

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