γ-Radiolysis of Room-Temperature Ionic Liquids: An EPR Spin-Trapping Study
| Autor: | Alexandra Lisovskaya, David M. Bartels, Peter Tarábek |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Materials science Radical Photochemistry Surfaces Coatings and Films law.invention Ion chemistry.chemical_compound chemistry law Ionic liquid Radiolysis Materials Chemistry Phosphonium Irradiation Physical and Theoretical Chemistry Electron paramagnetic resonance Alkyl |
| Zdroj: | The Journal of Physical Chemistry B. 123:10837-10849 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/acs.jpcb.9b09155 |
| Popis: | The radiolytic stability of a series of room-temperature ionic liquids (ILs) composed of bis(trifluoromethylsulfonyl)imide anion (Tf2N-) and triethylammonium, 1-butyl-1-methylpyrrolidinium, trihexyl(tetradecyl)phosphonium, 1-hexyl-3-methylpyridinium, and 1-hexyl-3-methylimidazolium (hmim) cations was studied using spin-trap electron paramagnetic resonance (EPR) spectroscopy with a spin-trap α-(4-pyridyl N-oxide)-N-tert-butylnitrone (POBN). The trapped radical yields were measured as a function of POBN concentration and as a function of radiation dose by double integration of the broad unresolved lines. Well-resolved motionally narrowed EPR spectra for the trapped radicals were obtained by dilution of the ILs with CH2Cl2 after irradiation. The trapped radicals were identified as mainly carbon-centered alkyl and •CF3, and their ratio varies greatly across the series of ILs. Expected nitrogen-centered radicals derived from Tf2N- were not observed. The hmim liquid proved most interesting because a large part of the trapped radical yield (entirely carbon-centered) grew in over several hours after irradiation. We also discovered a complicated narrow-line stable radical signal in this neat IL with no spin trap added, which grows in over several hours after irradiation and decays over several weeks. |
| Databáze: | OpenAIRE |
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