Spin-mapping of coal structures with ESE and ENDOR (Electron-Nuclear Double Resonance)
Our Laboratory is presently engaged in developing a method to model sulfur-containing compounds in whole coal. It has been established that most of the organic sulfur in coal exists in the form of aromatic groups known as thiophenes. Sulfur-containing aromatic compounds such as thiophene, tetraphenylthiophene and thianthrene were adsorbed onto silica-alumina catalyst surfaces were used as models to emulate coal's anisotropic nature and abundance of unpaired electron spin density. The spectroscopic techniques used were Electron Paramagnetic Resonance (EPR), Electron-Nuclear Double Resonance (ENDOR). EPR spectroscopy is a well established method to characterize g-matrix anisotropy in transition metal compounds. With increased resolution, EPR has become very useful for characterizing the small but still detectable g-matrix anisotropy in organic systems such as coal and the model systems for coal. ENDOR spectroscopy involves the inducement of NMR transitions of the nearby protons while detecting them with an EPR detection scheme which is several orders of magnitude more sensitive than using a NMR detection scheme. Analysis of the ENDOR spectra produced hyperfine information which is characteristic of these sulfur-containing systems. This information will be needed to resolve anisotropic hyperfine spectral features attributable to sulfur content in the analysis of coal macerals. 2 refs., 3 figs.
- Research Organization:
- Illinois Univ., Urbana, IL (USA)
- Sponsoring Organization:
- DOE/FE
- DOE Contract Number:
- FG22-88PC88921
- OSTI ID:
- 6501445
- Report Number(s):
- DOE/PC/88921-2; ON: DE91004346
- Country of Publication:
- United States
- Language:
- English
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Spin-mapping of coal structures with ESE and ENDOR
Spin-mapping of coal structures with ESE (Electron Spin Echo) and ENDOR (Electron-Nuclear Double Resonance)
Related Subjects
010600* -- Coal
Lignite
& Peat-- Properties & Composition
656002 -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANGULAR MOMENTUM
ANISOTROPY
AROMATICS
CARBONACEOUS MATERIALS
COAL
DOCUMENT TYPES
ENDOR
ENERGY SOURCES
FOSSIL FUELS
FUELS
HETEROCYCLIC COMPOUNDS
MACERALS
MAGNETIC RESONANCE
MATERIALS
MOLECULAR STRUCTURE
ORBITAL ANGULAR MOMENTUM
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PARTICLE PROPERTIES
PROGRESS REPORT
RESONANCE
SPECTRA
SPECTROSCOPY
SPIN
VITRINITE