scholarly journals Water-Soluble Pd Nanoparticles Synthesized from ω-Carboxyl-S-Alkanethiosulfate Ligand Precursors as Unimolecular Micelle Catalysts

2013 ◽  
Vol 5 (23) ◽  
pp. 12432-12440 ◽  
Author(s):  
Diego J. Gavia ◽  
May S. Maung ◽  
Young-Seok Shon
Keyword(s):  
Pd Nanoparticles ◽  
Water Soluble ◽  
Ligand Precursors

The Rational Design and Synthesis of Water-Soluble Thiourea Ligands for Recoverable Pd-Catalyzed Aerobic Aqueous Suzuki–Miyaura Reactions at Room Temperature

Synthesis ◽  
2018 ◽  
Vol 50 (07) ◽  
pp. 1499-1510 ◽  
Author(s):  
Wei Chen ◽  
Xiao-Yan Lu ◽  
Bei-Hua Xu ◽  
Wei-guo Yu ◽  
Zi-niu Zhou ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rational Design ◽  
Pd Nanoparticles ◽  
Water Soluble ◽  
Tem Analysis ◽  
Arylboronic Acids ◽  
Design And Synthesis ◽  
Black Precipitate ◽  
Aryl Bromides ◽  
Carboxylic Groups

Eight precatalysts containing carboxylic-functionalized thiourea ligands are prepared and their activities and recyclability are evaluated in aerobic aqueous Suzuki–Miyaura reactions. A bulky monothiourea–Pd complex, functionalized with four carboxylic groups, shows the best activity and recyclability in the coupling of aryl bromides with arylboronic acids. The catalyst can be reused at least five times without any significant reduction in its catalytic activity. TEM analysis and the confirmed catalytic activity of the observed black precipitate reveal that Pd nanoparticles are formed during the reactions and are stabilized by the carboxylic-functionalized thiourea ligands.

scholarly journals Kinetic Analysis of 4-Nitrophenol Reduction by “Water-Soluble” Palladium Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1169 ◽  
Author(s):  
Anas Iben Ayad ◽  
Denis Luart ◽  
Aissa Ould Dris ◽  
Erwann Guénin
Keyword(s):  
Thermodynamic Parameters ◽  
Sodium Borohydride ◽  
Catalytic Reduction ◽  
Pd Nanoparticles ◽  
Water Soluble ◽  
Reactant Ratio ◽  
First Order ◽  
Vis Spectroscopy ◽  
Pseudo First Order ◽  
Kinetics Of

The most important model catalytic reaction to test the catalytic activity of metal nanoparticles is the reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride as it can be precisely monitored by UV–vis spectroscopy with high accuracy. This work presents the catalytic reduction of 4-nitrophenol (4-Nip) to 4-aminophenol (4-Amp) in the presence of Pd nanoparticles and sodium borohydride as reductants in water. We first evaluate the kinetics using classical pseudo first-order kinetics. We report the effects of different initial 4-Nip and NaBH4 concentrations, reaction temperatures, and mass of Pd nanoparticles used for catalytic reduction. The thermodynamic parameters (activation energy, enthalpy, and entropy) were also determined. Results show that the kinetics are highly dependent on the reactant ratio and that pseudo first-order simplification is not always fit to describe the kinetics of the reaction. Assuming that all steps of this reaction proceed only on the surface of Pd nanoparticles, we applied a Langmuir−Hinshelwood model to describe the kinetics of the reaction. Experimental data of the decay rate of 4-nitrophenol were successfully fitted to the theoretical values obtained from the Langmuir–Hinshelwood model and all thermodynamic parameters, the true rate constant k, as well as the adsorption constants of 4-Nip, and BH4− (K4-Nip and KBH4−) were determined for each temperature.

Enhancing the biofuel upgrade performance for Pd nanoparticles via increasing the support hydrophilicity of metal–organic frameworks

2017 ◽  
Vol 201 ◽  
pp. 317-326 ◽  
Author(s):  
Qi Sun ◽  
Meng Chen ◽  
Briana Aguila ◽  
Nicholas Nguyen ◽  
Shengqian Ma
Keyword(s):  
Metal Organic Framework ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
Water Soluble ◽  
Pyrolysis Oil ◽  
Lignin Fraction ◽  
Catalytically Active ◽  
Metal Organic ◽  
Hydrophobic Nature ◽  
Supported Pd

In this work, the influence of the hydrophilic/hydrophobic nature of metal–organic framework (MOF) materials on the catalytic performance of supported Pd nanoparticles for biofuel upgrade was studied. We show that the introduction of hydrophilic groups on a MOF can greatly enhance the performance of the resultant catalyst. Specifically, Pd nanoparticles supported on MIL-101–SO3Na with superhydrophilicity (Pd/MIL-101–SO3Na) far outperforms pristine MIL-101 and the benchmark catalyst Pd/C in the hydrodeoxygenation reaction of vanillin, a model component of pyrolysis oil derived from the lignin fraction. This is attributed to a favorable mode of adsorption of the highly water soluble reactants on the more hydrophilic support in the vicinity of the catalytically active Pd nanoparticles, thereby promoting their transformation.

Aqueous-phase selective hydrogenation of phenol to cyclohexanone over soluble Pd nanoparticles

2014 ◽  
Vol 16 (5) ◽  
pp. 2664-2669 ◽  
Author(s):  
Jing-Fang Zhu ◽  
Guo-Hong Tao ◽  
Hang-Yu Liu ◽  
Ling He ◽  
Qian-Hui Sun ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Selective Hydrogenation ◽  
Pd Nanoparticles ◽  
Water Soluble ◽  
Mild Conditions ◽  
Highly Efficient

The water-soluble Pd nanoparticles are highly-efficient catalysts for the selective hydrogenation of phenol to cyclohexanone in water under mild conditions.

A Resorcinol-Formaldehyde Resin as an Embedding Material for Electron Microscopy of Membranes

1969 ◽  
Vol 27 ◽  
pp. 328-329 ◽  
Author(s):  
J. G. Robertson ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Osmium Tetroxide ◽  
Neutral Lipids ◽  
Lipid Extraction ◽  
Water Soluble ◽  
Formaldehyde Resin ◽  
Electron Microscope Autoradiography ◽  
Resorcinol Formaldehyde ◽  
Major Disadvantage ◽  
Cell Organization

The extraction of lipids from tissues during fixation and embedding for electron microscopy is widely recognized as a source of possible artifact, especially at the membrane level of cell organization. Lipid extraction is also a major disadvantage in electron microscope autoradiography of radioactive lipids, as in studies of the uptake of radioactive fatty acids by intestinal slices. Retention of lipids by fixation with osmium tetroxide is generally limited to glycolipids, phospholipids and highly unsaturated neutral lipids. Saturated neutral lipids and sterols tend to be easily extracted by organic dehydrating reagents prior to embedding. Retention of the more saturated lipids in embedded tissue might be achieved by developing new cross-linking reagents, by the use of highly water soluble embedding materials or by working at very low temperatures.

Ferritin Labeled Antibody Staining of Thin Sections

1969 ◽  
Vol 27 ◽  
pp. 420-421
Author(s):  
J. D. McLean ◽  
S. J. Singer
Keyword(s):  
Biological Material ◽  
Water Soluble ◽  
Thin Sections ◽  
Antibody Staining ◽  
Thin Sectioning ◽  
Ultrathin Sections

The successful application of ferritin labeled antibodies (F-A) to ultrathin sections of biological material has been hampered by two main difficulties. Firstly the normally used procedures for the preparation of material for thin sectioning often result in a loss of antigenicity. Secondly the polymers employed for embedding may non-specifically absorb the F-A. Our earlier use of cross-linked polyampholytes as embedding media partially overcame these problems. However the water-soluble monomers used for this method still extract many lipids from the material.

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