Investigation of Sapropelite Coals by Means of NMR Spectroscopy
N. I. FEDOROVA1, S. YU. LYRSHCHIKOV1, V. YU. MALYSHEVA1, Z. R. ISMAGILOV1,2
1Federal Research Centre of Coal and Coal Chemistry, Siberian Branch of the Russian Academy of Sciences, Kemerovo, Russia
2Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: sapropelite coals, kerogen, elemental composition, NMR spectroscopy, degree of aromaticity
Pages: 604-610
Abstract
Seven samples of sapropelite coals from the deposits differing from each other in the catagenetic maturity of the organic matter were studied by means of solid-state 13C NMR spectroscopy. Analysis of the obtained analytical data showed that carbon in the organic mass of the samples is largely concentrated in aliphatic structures since the most intense signals in the 13C NMR spectrum fall on the region of 0-50 ppm, corresponding to the absorption of carbon of methyl and methylene groups, as well as tertiary and quaternary carbon atoms. The largest amount of aliphatic carbon was found in the sample, which is characterized by the highest values of the yield of volatiles and the H/C atomic ratio. It was found that with a decrease in the H/C atomic ratio in the samples, their degree of aromaticity increases against the background of a decrease in the proportion of aliphatic structures and carbon bonded to oxygen by a single bond.
DOI: 10.15372/CSD2021339
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