Spectroscopic Characterization of Wilkinson's Catalyst Using X-ray Photoelectron Spectroscopy (ESCA)

1982 ◽  
Vol 36 (3) ◽  
pp. 290-296 ◽  
Author(s):  
Manuel Carvalho ◽  
Larry F. Wieserman ◽  
David M. Hercules
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Analytical Techniques ◽  
Spectroscopic Characterization ◽  
Homogeneous Hydrogenation ◽  
X Ray ◽  
Wilkinson’S Catalyst ◽  
Ft Ir ◽  
Wilkinson's Catalyst

Wilkinson's catalyst, RhCl(PPh3)3 is a well known and widely used homogeneous hydrogenation catalyst. This catalyst was analyzed by ESCA which revealed that two rhodium species [Rh(I) and Rh(III)] were present, both for commercial preparations and for catalysts prepared in this laboratory. The ratio of Rh(I) to Rh(III) was 3:2 regardless of the source. A different method of synthesizing RhCl(PPh3)3 was used and produced a compound having only Rh(I) species. Additional analytical techniques such as elemental analysis, FT-IR, liquid chromatography, and 31P NMR were used to determine the origin of the higher binding energy peaks when Wilkinson's procedure was used to prepare RhCl(PPh3)3. Hydrogenation of cyclohexene was also performed to determine the effect of the higher binding energy species on catalytic activity.

scholarly journals Hydrogenative Cyclization of Levulinic Acid to γ-Valerolactone with Methanol and Ni-Fe Bimetallic Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1096
Author(s):  
Ligang Luo ◽  
Xiao Han ◽  
Qin Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Levulinic Acid ◽  
Hydrogen Donor ◽  
Effect Of Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
Temperature Programmed

A series of Ni-Fe/SBA-15 catalysts was prepared and tested for the catalytic hydrogenation of levulinic acid to γ-valerolactone, adopting methanol as the only hydrogen donor, and investigating the synergism between Fe and Ni, both supported on SBA-15, towards this reaction. The characterization of the synthesized catalysts was carried out by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), H2-TPD (hydrogen temperature-programmed desorption), XPS (X-ray photoelectron spectroscopy), and in situ FT-IR (Fourier transform–infrared spectroscopy) techniques. H2-TPD and XPS results have shown that electron transfer occurs from Fe to Ni, which is helpful both for the activation of the C=O bond and for the dissociative activation of H2 molecules, also in agreement with the results of the in situ FT-IR spectroscopy. The effect of temperature and reaction time on γ-valerolactone production was also investigated, identifying the best reaction conditions at 200 °C and 180 min, allowing for the complete conversion of levulinic acid and the complete selectivity to γ-valerolactone. Moreover, methanol was identified as an efficient hydrogen donor, if used in combination with the Ni-Fe/SBA-15 catalyst. The obtained results are promising, especially if compared with those obtained with the traditional and more expensive molecular hydrogen and noble-based catalysts.

scholarly journals Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

Magnetic Nanoparticle Supported Ionic Liquid Phase Catalyst for Oxidation of Alcohols

2020 ◽  
Vol 73 (11) ◽  
pp. 1088
Author(s):  
Altafhusen Naikwade ◽  
Megha Jagadale ◽  
Dolly Kale ◽  
Gajanan Rashinkar
Keyword(s):  
Ionic Liquid ◽  
Liquid Phase ◽  
Photoelectron Spectroscopy ◽  
Magnetic Nanoparticle ◽  
Analytical Techniques ◽  
X Ray ◽  
Supported Ionic Liquid ◽  
Transmission Electron ◽  
Oxidation Of Alcohols ◽  
Ft Ir

A new magnetic nanoparticle supported ionic liquid phase (SILP) catalyst containing perruthenate anions was prepared by a multistep procedure. The various analytical techniques such as FT-IR spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, thermogravimetric analysis, energy dispersive X-ray analysis, and vibrating sample magnetometer analysis ascertained the successful formation of catalyst. The performance of a magnetically retrievable SILP catalyst was evaluated in the selective oxidation of alcohols. The split test and leaching studies of the SILP catalyst confirmed its heterogeneous nature. In addition, the reusability potential of SILP catalyst was also investigated which revealed its robust activity up to six consecutive cycles.

Preparation and Characterization of TiO2 Nanoparticle with SiO2 Shell

2011 ◽  
Vol 233-235 ◽  
pp. 1188-1191
Author(s):  
Hong Cai ◽  
Yan Chen ◽  
Yun Ying Wu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Chemical Components ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Bonding Phase ◽  
Hydrolysis Of

Nano-TiO2 particles were prepared by sol-gel method, of which the surfaces were coated by SiO2. The coating was achieved by the hydrolysis of sodium silicate (Na2SiO3) in ammonium chloride (NH4Cl). The surface bonding, phase constitution and chemical components of the samples were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy (XPS). The mechanism of the SiO2 coating process onto TiO2 surface was analyzed. Results show that SiO2 particles were immobilized on the TiO2 surface via Ti—O—Si bondings, which formed at the interface. The SiO2 layer on TiO2 surface was amorphous, the photocatalytic performance was decreased of the TiO2 while its stability was enhanced after surface modification.

Synthesis and Characterization of Polyacrylate Latex Containing Fluorine and Silicon

2012 ◽  
Vol 151 ◽  
pp. 392-395 ◽  
Author(s):  
Xiao Hui Gao ◽  
Yu Feng Li ◽  
Hong Chao Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
X Ray ◽  
Air Interface ◽  
Transmission Electron ◽  
Ft Ir ◽  
Core Shell Structure ◽  
Thermal Stability Of ◽  
Seed Emulsion Polymerization

Polyacrylate latex containing fluorine and silicon was successfully synthesized by semi-continuous seed emulsion polymerization, using organic silicon(OSi) monomer, fluorocarbon(FC), methacrylic acid(MAA), and butyl acrylate(BA) as raw materials. Transmission electron microscope(TEM) characterization indicated that the latex particles were form uniform analogous core-shell structure. Dynamic light scattering(DLS) show a narrow size distribution. The results of X-ray photoelectron spectroscopy(XPS) revealed the fluorine and silicon transfer to the film-air interface. The reaction was evaluated using fourier transform infrared(FT-IR) spectrum. The thermal stability of the latex films which analysed by thermogravimetric(TG) was improved due to the join of OSi and FC.

In situ X-ray photoelectron and Auger electron spectroscopic characterization of reaction mechanisms during Li-ion cycling

2016 ◽  
Vol 52 (90) ◽  
pp. 13257-13260 ◽  
Author(s):  
Ching-Yen Tang ◽  
Richard T. Haasch ◽  
Shen J. Dillon
Keyword(s):  
Photoelectron Spectroscopy ◽  
Reaction Mechanisms ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Spectroscopic Characterization ◽  
X Ray ◽  
Li Ion ◽  
Novel Design

We demonstrate a novel design for in situ X-ray photoelectron spectroscopy and in situ Auger electron spectroscopy, and we applied this technique to characterize the evolution of bonding and chemistry during cycling of nanoparticle electrodes.

scholarly journals XPS and FT-IR Characterization of Selected Synthetic Corrosion Products of Zinc Expected in Neutral Environment Containing Chloride Ions

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Juliusz Winiarski ◽  
Włodzimierz Tylus ◽  
Katarzyna Winiarska ◽  
Irena Szczygieł ◽  
Bogdan Szczygieł
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Chloride Ions ◽  
Corrosion Products ◽  
Zinc Alloy ◽  
Solid State Method ◽  
X Ray ◽  
Ft Ir ◽  
Atr Spectroscopy

ZnO, Zn(OH)2, Zn5(OH)8Cl2·H2O, ZnCO3, and Zn5(CO3)2(OH)6 synthetic powders were prepared by chemical or solid-state method. Their crystalline phase structure, thermal behavior, and morphology were examined. Characteristic infrared absorbance bands were estimated by means of FT-IR ATR spectroscopy. X-ray photoelectron spectroscopy (XPS) allowed to calculate the modified Auger parameters (α ′) thereof to 2010.2, 2009.3, 2009.4, 2009.7, and 2009.8 eV, respectively for ZnO, Zn(OH)2, Zn5(OH)8Cl2·H2O, ZnCO3, and Zn5(CO3)2(OH)6. Finally, comparison of surface composition may be crucial to evaluation of the unknown experimental spectra of corrosion products formed on the surface of zinc alloy coatings exposed in NaCl solution.

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