9 and 34 GHz EPR study of the free radicals in various asphaltenes: Statistical correlation of the g-values with heteroatom content |
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Authors: | VM Malhotra HA Buckmaster |
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Institution: | Department of Physics, The University of Calgary, Calgary, Alberta, Canada T2N 1N4 |
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Abstract: | The 9 and 34 GHz EPR spectra of eight asphaltenes from different locations have been studied at 294 K in an attempt to correlate the observed g-values with the heteroatom content. It is found that the EPR linewidths are larger and the g-values are smaller at 34 GHz than at 9 GHz. Quantitative statistical analysis of the g-values observed in those asphaltenes derived from tar sand bitumens and crude oils shows that they are uncorrelated with the heteroatom content, unlike those from coal. It is concluded that g-values may not be a good analytical tool for elucidating the structure of those asphaltenes not derived from coal. |
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Keywords: | EPR free radicals asphaltenes heteroatoms correlation |
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