Interaction of Freshly Exposed Low- and Medium-Grade Coal with the Air

The chemical composition of low- and medium grade Russian coal (ranks G, DZh, and Zh) on first exposure to the air is analyzed. The changes in the coal’s organic matter are recorded by means of diffuse-reflection infrared (IR) spectroscopy, electron paramagnetic resonance (EPR), and nuclear magnetic...

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Bibliographic Details
Published in:Coke and chemistry (New York, N.Y.) N.Y.), 2023-04, Vol.66 (4), p.187-195
Main Authors: Semenova, S. A., Patrakov, Yu. F., Lyrshchikov, S. Yu, Zakharov, N. S.
Format: Article
Language:English
Subjects:
Chemical composition
Chemistry
Chemistry and Materials Science
Coal
Electron paramagnetic resonance
Exposure
Functional groups
Industrial Chemistry/Chemical Engineering
Infrared reflection
Infrared spectroscopy
NMR spectroscopy
Organic matter
Surface layers
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Summary:The chemical composition of low- and medium grade Russian coal (ranks G, DZh, and Zh) on first exposure to the air is analyzed. The changes in the coal’s organic matter are recorded by means of diffuse-reflection infrared (IR) spectroscopy, electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR) spectroscopy. The variation in the number of paramagnetic centers and functional groups shows that the most significant changes in the structural fragments and surface layer of the coal occur within hours of exposure. Without further disturbance, residence in air for several days is accompanied by slow accumulation and loss of the radicals and the formation of functional O groups. For coal of low and moderate metamorphic development, • CH alkyl radicals and CO • phenyl and alkyl ester radicals react most with atmospheric oxygen.
ISSN:1068-364X
1934-8398
DOI:10.3103/S1068364X23700709