High-resolution {sup 1}H NMR studies of Argonne Premium coals

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:441416

Jurkiewicz, A; Bronnimann, C E; Maciel, G E ^[1]

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1. Colorado Stae Univ., Fort Collins, CO (United States)

Proton combined rotation and multiple-pulse spectroscopy (CRAMPS) studies were performed on untreated and pyridine-treated samples of seven Argonne Premium coals. The proton CRAMPS spectrum of an untreated sample usually consists of two substantially overlapping peaks, an aliphatic peak and an aromatic peak. In the spectrum of a sample saturated with erdeuteropyridine, the aliphatic and aromatic peaks are better resolved, and more spectral and structural details can be elucidated. The addition of pyridine can dramatically change the structural or dynamic characteristics of a coal. In a proton CRAMPS dipolar-dephasing experiment on an untreated coal, the protons of aliphatic moieties relax faster than those attached to aromatic rings. In pyridine-treated samples, the dynamics are far more complicated and vary within each sample. The spectral resolution increases with increasing dephasing interval. Peaks due to protons belonging to heterocyclic nitrogen and sulfur compounds were identified. A correlation between the chemical shift of the aliphatic peak and the hydrogen/carbon ratio was found for 19 coal samples. 19 refs., 8 figs., 2 tabs

• DOE Contract Number: AC22-88PC88813
• OSTI ID: 441416
• Report Number(s): CONF-891206--; CNN: Grant CHE-8616437
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
40 CHEMISTRY
CARBON
CHEMICAL COMPOSITION
CHEMICAL SHIFT
COAL
CONCENTRATION RATIO
HYDROGEN
LINE BROADENING
NITROGEN
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
PEAKS
PULSE TECHNIQUES
PYRIDINE
RESOLUTION
SATURATION
SPECTROSCOPY
SPIN-SPIN RELAXATION
SULFUR COMPOUNDS