Study of the oxidized and non- oxidized bitumen modified with additive «Adgezolin» by using electron paramagnetic resonance

Mukhamatdinov, Irek I.; Gafurov, Marat; Кемалов, А. Ф.; Родионов, А. А.; Mamin, G. V.; Fakhretdinov, P. S.

doi:10.1088/1755-1315/155/1/012004

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…The EPR line shape of the free radical at the X-band could be described satisfactorily as a sum or a convolution of Gaussian and Lorentzian, with Γ G ≈ Γ L = 0.815 mT, the ratio G:L = 19:81 (for the linear combination), and an isotropic g -factor of 2.0042 ± 0.0002. The diversity of g -values in oil disperse systems is, among other reasons, attributed to the spin–orbit coupling of unpaired electrons and the existing heteroatoms.…”

Section: Resultsmentioning

confidence: 95%

“…Indeed, another main reason to choose the particular crude oil sample used in this work is to exclude a possible influence of other paramagnetic species on proton relaxation 24 or electronic relaxation times (saturation of EPR transitions). 41 The EPR line shape of the free radical at the X-band could be described satisfactorily as a sum or a convolution of Gaussian and Lorentzian, 42 with Γ G ≈ Γ L = 0.815 mT, the components of the oil under study. Furthermore, the presence of phenoxy radicals partially localized in aromatic systems due to the oxygen might be the reason for the observed high value of the g-factor.…”

Section: Resultsmentioning

confidence: 99%

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Proton–Radical Interaction in Crude Oil—A Combined NMR and EPR Study

et al. 2018

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We present a detailed study of electron/nuclear interaction in a specific crude oil by continuous-wave and pulsed EPR, electron–nuclear double resonance (ENDOR) at W-band (94 GHz), and fast field-cycling dynamic nuclear polarization (FFC-DNP) at X-band. A perceptible non-Overhauser (solid) effect is found at room temperature as a result of the polarization transfer from the intrinsic oil “free” radicals to the 1H nuclei with different dynamics. On the basis of the analysis of the longitudinal nuclear relaxation times, three dynamical components described by different electron–proton coupling parameters were found, which in combination with ENDOR provides information about the distribution of the radicals in the high-molecular oil components.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Proton–Radical Interaction in Crude Oil—A Combined NMR and EPR Study

et al. 2018

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Application of pulsed and high-frequency electron paramagnetic resonance techniques to study petroleum disperse systems

et al. 2020

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The spectral and relaxation characteristics of “free” organic radicals (FR) and vanadyl-porphyrin (VP) complexes in various petroleum disperse systems (PDS) like bitumen, petroleum, their high-molecular components and solutions were studied using stationary (conventional) and pulsed electron paramagnetic resonance (EPR) techniques in two frequency ranges (X- and W-bands, with the microwave radiation frequencies of about 9 GHz and 95 GHz, respectively). The features of the pulsed approaches (electron spin echo, modulation of the electron spin echo signal decay, electronic relaxation times) and high-frequency EPR for PDS investigations were examined. W-band EPR allows to resolve spectrally the lines from the different paramagnetic centers and more accurately determine their spectral characteristics. It is shown that the electron spin echo can be observed at room temperatures even at high magnetic fields of 3.4 T demonstrating the potential of application of pulsed EPR techniques for the low-cost oilfield measurements. Analysis of the VP transverse magnetization decay curve permits to identify electron-nuclear interactions with the 14N and 1H nuclei in situ while in the EPR spectra these hyperfine interactions usually cannot be detected. It is found from the W-band EPR measurements that FR lineshape cannot be fitted with isotropic parameters in contrast to the established X-band results. The observed effect of increasing the rates of electronic transverse relaxation in asphaltenes is described in the framework of a model of spectral diffusion between the fast- and slow-relaxing paramagnetic centers in supramolecular complexes of asphaltenes.

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Study of the oxidized and non- oxidized bitumen modified with additive «Adgezolin» by using electron paramagnetic resonance

Cited by 2 publications

References 9 publications

Proton–Radical Interaction in Crude Oil—A Combined NMR and EPR Study

Proton–Radical Interaction in Crude Oil—A Combined NMR and EPR Study

Application of pulsed and high-frequency electron paramagnetic resonance techniques to study petroleum disperse systems

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