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 coals model. Along the same lines the authors 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. The authors have concentrated on a theoretical treatment of pairs of tightly coupled spin {1/2} nuclei under magic angle spinning conditions. The average Hamiltonian theory developed here is required for a quantitative understanding of two dimensional NMR experiments of such spin pairs in solids. These experiments in turn provide a means of determining connectivities between resonances in solid state NMR spectra. Development of these techniques will allow us to establish connectivities between functional components in coals. The complete description of these spin dynamics has turned out to be complex, and is necessary to provide a foundation upon which such experiments may be quantitatively interpreted in complex mixtures such as coals. 25 refs., 4 figs., 3 tabs.
- 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:
- 5925739
- Report Number(s):
- DOE/PC/79910-10; ON: DE91011284
- 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
NUCLEAR MAGNETIC RESONANCE
PERFORMANCE TESTING
CARBON 13
CHEMICAL SHIFT
CROSS-LINKING
HAMILTONIAN FUNCTION
MOLECULAR STRUCTURE
NMR SPECTRA
POLARIZATION
PROGRESS REPORT
RELAXATION
SPIN
ANGULAR MOMENTUM
CARBON ISOTOPES
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
DOCUMENT TYPES
ENERGY SOURCES
EVEN-ODD NUCLEI
FOSSIL FUELS
FUELS
FUNCTIONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
NUCLEI
PARTICLE PROPERTIES
POLYMERIZATION
RESONANCE
SPECTRA
STABLE ISOTOPES
TESTING
010600* - Coal
Lignite
& Peat- Properties & Composition