Two dimensional NMR and NMR relaxation studies of coal structure
This report covers the progress made on the title project and summarizes the accomplishments for the project period. Four major areas of inquiry have been pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups in coals that determine the reactivity of coals. Other methods are being developed which will also determine how these functional groups are linked together. A third area of investigation concerns how molecular mobility in coals impacts NMR relaxation times, which is important for interpretation of such data in terms of the mobile phase in coal models. Along the same lines the author are also using these studies to establish protocols for obtaining the best quantitative response from coals in solid state C-13 NMR spectra. The effects of very high MAS rates (>10 kHz) on cross polarization dynamics are also being investigated for similar reasons. During the last quarter the authors has concentrated on improvements in cross polarization (CP) sequences with a goal of making the CP process insensitive to experimental conditions such as the Hartmann-Hahn mismatch. It has been found that the usual theories of CP are incorrect, and that the CP process is very heterogeneous in nature. This has significant implications on methods typically used in quantifying {sup 13}C CPMAS spectra of coals. 19 refs., 11 figs.
- Research Organization:
- Yale Univ., New Haven, CT (USA). Dept. of Chemistry
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- FG22-87PC79910
- OSTI ID:
- 5901966
- Report Number(s):
- DOE/PC/79910-8; ON: DE91011282
- Country of Publication:
- United States
- Language:
- English
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Two dimensional NMR and NMR relaxation studies of coal structure
Two dimensional NMR and NMR relaxation studies of coal structure
Related Subjects
COAL
STRUCTURAL CHEMICAL ANALYSIS
ACTIVATION ENERGY
AROMATICS
CARBON
CARBON 13
DISTRIBUTION
MEASURING METHODS
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
PROGRESS REPORT
RELAXATION TIME
SPIN-SPIN RELAXATION
CARBON ISOTOPES
CARBONACEOUS MATERIALS
DOCUMENT TYPES
ELEMENTS
ENERGY
ENERGY SOURCES
EVEN-ODD NUCLEI
FOSSIL FUELS
FUELS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
NONMETALS
NUCLEI
ORGANIC COMPOUNDS
RELAXATION
RESONANCE
STABLE ISOTOPES
010600* - Coal
Lignite
& Peat- Properties & Composition