40936-29-6Relevant academic research and scientific papers
Hydroxyl radical generation by dissociation of water molecules during 1.65?MHz frequency ultrasound irradiation under aerobic conditions
Miyaji, Akimitsu,Kohno, Masahiro,Inoue, Yoshihiro,Baba, Toshihide
, p. 178 - 182 (2017/02/05)
The dissociation of water molecules by ultrasound irradiation under aerobic conditions was demonstrated experimentally. To be able to detect the dissociation of water molecules, we performed the ultrasound irradiation of 17O-labelled water (H217O) under aerobic conditions. The hydroxyl and hydrogen radicals generated during the ultrasound irradiation process were trapped with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and electron spin resonance (ESR) spectroscopy was performed on the DMPO spin adducts. In the ESR spectrum, a 15-line signal attributable to the trapping of the hydroxyl radicals containing 17O (17OH radicals) by DMPO together with a 4-line signal attributable to the trapping of the hydroxyl radicals containing 16O (16OH radicals) by DMPO were observed. The generation of 17OH radicals indicated that H217O was dissociated by the sonolysis process under aerobic conditions. On the other hand, the ESR signal attributable to the trapping of hydrogen radicals by DMPO was not observed, suggesting that hydrogen radicals were not generated during the dissociation of water molecules.
ESR study of spin adducts of the direct electrocatalytic decomposition of light aliphatic alcohols in a polymer electrolyte fuel cell
Kadirov,Valitov,Nizameev,Kadirov,Mirkhanov
experimental part, p. 1543 - 1548 (2011/05/03)
Spin adducts of methanol and ethanol electrocatalytic oxidation were detected by the spin trap method using a tiny H2/O2 fuel cell (FC) designed for ESR in situ with a Nafion/Pt membrane electrode assembly. Spin adducts of intermediates of the direct electrooxidation of ethanol, which have not been observed earlier, were obtained by the variation of oxidation conditions, in particular, the FC potential. The work of the FC was controlled by monitoring the diagnostic curves potential3-current density, power density3-current density, and efficiency-power density.
Spin trapping of Au-H intermediate in the alcohol oxidation by supportedand unsupported gold catalysts
Conte, Marco,Miyamura, Hiroyuki,Kobayashi, Shu,Chechik, Victor
supporting information; experimental part, p. 7189 - 7196 (2009/09/30)
Electron paramagnetic resonance (EPR) spectroscopy and spin trapping were used to explore the mechanism of alcohol oxidation over gold catalysts. Reaction of secondary alcohols with supported and unsupported gold catalysts (e.g., Au/CeO2, polymer-Incarcerated Au nanoparticles,PPh 3-protected Au nanoparticles) In the presence of spin tr aps led to the formation of a hydrogen spin adduct. Using Isotope labeling, we confirmed that the hydrogen In the spin adduct originates from the cleavage of the C-H bond In the alcohol molecule. The formation of thehydrogen spin adduct most likely results from the abstraction of hydrog en from the Au surface by a spin trap. These results thus strongly suggest Intermediate formation of Au-H species during alcohol oxidation. The role of oxygen In this mechanism Is to restore the catalytic activity rather than oxidize alcohol. This was further confirmed by carrying out gold-catalyzed alcohol oxidation In the absence of oxygen, with nitroxidesas hydrogen abstractors. The support (e.g., metal oxides) can activate oxygen and act as an H abstractor from the gold surface and hence lead t o a faster recovery of the activity. Peroxyl radicals were also observedduring alcohol oxidation, consistent with a free-radical autoxidation m echanism. However, this mechanism Is likely to be a minor side reaction,which does not lead to the formation of an appreciable amount of oxidat ion products.
