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Electron and proton magnetic resonance spectroscopic investigation of anthracene oxidation

The work reports a method for monitoring anthracene radical-mediated oxidation reactions using electron paramagnetic resonance (EPR) spectroscopy. The formation of anthracene dimer product was well-defined using (1)H-NMR and (1)H–(1)H correlation spectroscopy (COSY). Unrestricted 3-21G/B3LYP DFT was...

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Detalles Bibliográficos
Autores principales: Morsy, Mohamed A., Kawde, Abdel-Nasser M., Kamran, Muhammad, Garrison, Thomas F., Iali, Wissam, Alharthi, Salman S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8639432/
https://www.ncbi.nlm.nih.gov/pubmed/34901508
http://dx.doi.org/10.1016/j.heliyon.2021.e08474
Descripción
Sumario:The work reports a method for monitoring anthracene radical-mediated oxidation reactions using electron paramagnetic resonance (EPR) spectroscopy. The formation of anthracene dimer product was well-defined using (1)H-NMR and (1)H–(1)H correlation spectroscopy (COSY). Unrestricted 3-21G/B3LYP DFT was used to estimate radical hyperfine spacing (hfs), then to identify the characteristic EPR-spin transitions of anthracene radical intermediate. A detailed investigation of an anthracene oxidation reaction and its possible reaction mechanism in concentrated sulphuric acid is conducted as a model system for polyaromatic hydrocarbons. Peak-to-peak (p2p) intensities of selected EPR-spectral lines were used to evaluate anthracene's oxidation kinetic model. The findings showed that radical intermediate formation is a unimolecular autocatalytic process, dimerization is a pseudo-zero-order reaction, and the latter is the rate-determining step with a half-life of 48 ± 2 min at 25.0 °C.