Spin-mapping of coal structures with ESE and ENDOR. Eighth quarterly (second annual) report
A nondestructive method to determine the atomic and molecular structures present in the organic (maceral) components of whole coal and coal products has been sought for many years. This program of research is designed to address that analytical need by applying advanced electron magnetic resonance techniques to the determination of coal molecular structure. Structural information has be obtained by using the naturally occurring unpaired electrons in coal as ``observation posts`` from which to survey neighboring atoms through the electron-nuclear hyperfine interaction. Such an overall approach has been termed ELECTRON SPIN MAPPING of coal structure. New techniques like 2-dimensional ENDOR and ESE spectroscopies and multifrequency EPR, including the world`s first S-band ESE spectrometer and one of the first W-band instruments, which we have developed in our laboratory, were employed in the determination. The materials studied were well separated macerals obtained by density gradient centrifugation techniques from Illinois {number_sign}6 coals, a well as whole Illinois {number_sign}6, {number_sign}5, and Argonne Premium Sample Coals. model compounds, chosen to represent molecular structures typical of those believed to exist in coal also were studied by the various electron magnetic resonance (EMR) methods. Utilizing the various EMR methods available in our laboratory, we studied approaches to determine parameters that direcly reflect the atomic and molecular structure of coal. The naturally occurring unpaired electrons in coal were utilized as probes of their local environment, which they reflect through hyperfine interactions with neighboring 1 > 0 nuclei (eg, {sup 1}H, {sup 13}C).
- Research Organization:
- Univ. of Illinois at Urbana-Champaign, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-88PC88921
- OSTI ID:
- 10107849
- Report Number(s):
- DOE/PC/88921-8; ON: DE92004498
- Resource Relation:
- Other Information: PBD: 1 Sep 1990
- Country of Publication:
- United States
- Language:
- English
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Spin-mapping of coal structures with ESE and ENDOR (Electron-Nuclear Double Resonance)