Aromatic and aliphatic carbon contents of coals and oil shales by /sup 13/C NMR

Conference · Sun Jan 01 04:00:00 EST 1978 · Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States)

OSTI ID:6831431

Maciel, G E ^[1]; Bartuska, V J; Miknis, F P

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1. Colorado State Univ., Fort Collins

From /sup 13/C nmr spectra quantitative determinations of aromatic/olefinic and aliphatic carbon contents can be made. However, many questions must be raised to determine the reliability of this approach for quantitative analytical purposes. These questions revolve largely about the dynamics of the experiment, i.e., the characteristic relaxation times of the pertinent processes. The essential question is: can experimental conditions and corrections be found so that all organic carbon types are ''counted'' equally in the /sup 13/C experiment. Many experiments have been carried out to characterize the conditions for typical coals and oil shales, so that optimized experiments could be designed. Comparisons with experiments carried out with high-power /sup 1/H decoupling, but without /sup 13/C-/sup 1/H cross polarization, are essential for assessing the efficiency and deviations from uniformity of the cross polarization process. One key feature of calibrating the /sup 13/C approach so that absolute aromatic/olefinic or aliphatic carbon contents can be determined is an external /sup 13/C standard. The requirements for an external standard involve both the chemical shift (to avoid critical peak overlaps) and relaxation times (to avoid intensity distortions). With a method capable of determining aromatic/olefinic and aliphatic carbon contents, various comparisons and correlations are possible. These include comparisons among related samples (e.g., oil shale and shale oil; coal and solvent-refined coal or hydrogenated coal), and correlations with pertinent fuel parameters, e.g., gal/ton obtained from oil shale or Btu/ton for coal or oil shale.

• OSTI ID: 6831431
• Report Number(s): CONF-780902-P2
• Conference Information: Journal Name: Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States) Journal Volume: 23:4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
04 OIL SHALES AND TAR SANDS
040500 -- Oil Shales & Tar Sands-- Properties & Composition
AROMATICS
BITUMINOUS MATERIALS
CARBON 13
CARBON ISOTOPES
CARBONACEOUS MATERIALS
CHEMICAL COMPOSITION
COAL
ENERGY SOURCES
EVEN-ODD NUCLEI
FOSSIL FUELS
FUELS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
OIL SHALES
ORGANIC COMPOUNDS
RESONANCE
STABLE ISOTOPES