eesti teaduste
akadeemia kirjastus
SINCE 1984
Oil Shale cover
Oil Shale
ISSN 1736-7492 (Electronic)
ISSN 0208-189X (Print)
Impact Factor (2020): 0.934

Structural characterization of Huadian oil shale kerogen by using 13C DP/MAS NMR; pp. 181–198

Full article in PDF format | 10.3176/oil.2021.3.01

Xiaoye Wang, Yulong You, Mao Mu, Xiangxin Han, Jie Shu, Xiumin Jiang


Quantitative 13C direct polarization/magic angle spinning (DP/MAS) solid-state nuclear magnetic resonance (SSNMR) was used to characterize type I kerogen isolated from Huadian oil shale. The DP/MAS results showed that this kerogen was highly aliphatic and its aromaticity (fa) was as low as 20.23%. The average aliphatic carbon chain length (Cn), average aromatic cluster size (C) and substitute degree of aromatic rings (σ) were calculated. The NMR-derived H/C and O/C atomic ratios (RH/C and RO/C) obtained by DP were in agreement with the corresponding results of ultimate analysis, indicating the accuracy of DP for quantification. Besides, using varying contact times cross polarization (CP) spectra were obtained at the same MAS frequency as the DP spectrum. Regardless of contact time, the aromaticities derived from CP were much lower than that from DP. Consequently, the RH/C value from CP was significantly higher than that of ultimate analysis. The contribution of spinning sidebands could be ignored with the MAS frequency up to 10 kHz. It is concluded that DP with a high MAS frequency is necessary for gaining quantitative structural information about kerogen, especially for its molecular modeling.


1. Tissot, B. P., Welte, D. H. Petroleum Formation and Occurrence. Springer-Verlag, New York, 1984.

2. Han, X. X., Kulaots, I., Jiang, X. M., Suuberg, E. M. Review of oil shale semicoke and its combustion utilization. Fuel, 2014, 126, 143‒161.

3. Oh, M. S., Taylor, R. W., Coburn, T. T., Crawford, R. W. Ammonia evolution during oil shale pyrolysis. Energy Fuels, 1988, 2(1), 100‒105.

4. Behar, F., Vandenbroucke, M. Chemical modelling of kerogens. Org. Geochem., 1987, 11(1), 15‒24.

5. Trewhella, M. J., Poplett, I.J. F., Grint, A. Structure of Green River oil shale kerogen: Determination using solid state 13C n.m.r. spectroscopy. Fuel, 1986, 65(4), 541‒546.

6. Kister, J., Guiliano, M., Largeau, C., Derenne, S., Casadevall, E. Characterization of chemical structure, degree of maturation and oil potential of Torbanites (type I kerogens) by quantitative FT-i.r. spectroscopy. Fuel, 1990, 69(11), 1356‒1361.

7. Kelemen, S. R., Freund, H., Gorbaty, M. L., Kwiatek, P. J. Thermal chemistry of nitrogen in kerogen and low-rank coal. Energy Fuels, 1999, 13(2), 529‒538.

8. Kelemen, S. R., Afeworki, M., Gorbaty, M. L., Sansone, M., Kwiatek, P. J., Walters, C. C., Freund, H., Siskin, M., Bence, A. E., Curry, D. J., Solum, M., Pugmire, R. J., Vandenbroucke, M., Leblond, M., Behar, F. Direct characterization of kerogen by X-ray and solid-state 13C nuclear magnetic resonance methods. Energy Fuels, 2007, 21(3), 1548‒1561.

9. Fletcher, T. H., Gillis, R., Adams, J., Hall, T., Mayne, C. L., Solum, M. S., Pugmire, R. J. Characterization of macromolecular structure elements from a Green River oil shale, II. Characterization of pyrolysis products by 13C NMR, GC/MS, and FTIR. Energy Fuels, 2014, 28(5), 2959‒2970.

10. Wang, Q., Hou, Y. C., Wu, W. Z., Yu, Z., Ren, S. H., Liu, Q. Y., Liu, Z. Y. A study on the structure of Yilan oil shale kerogen based on its alkali-oxygen oxidation yields of benzene carboxylic acids, 13C NMR and XPS. Fuel Process. Technol., 2017, 166, 30‒40.

11. Chu, W. Y., Cao, X. Y., Schmidt-Rohr, K., Birdwell, J. E., Mao, J. D. Investigation into the effect of heteroatom content on kerogen structure using advanced 13C solid-state nuclear magnetic resonance spectroscopy. Energy Fuels, 2019, 33(2), 645‒653.

12. Cao, X. Y., Yang, J., Mao, J. D. Characterization of kerogen using solid-state nuclear magnetic resonance spectroscopy: A review. Int. J. Coal Geol., 2013, 108, 83‒90.

13. Pines, A., Gibby, M. G., Waugh, J. S. Proton-enhanced NMR of dilute spins in solids. J. Chem. Phys., 1973, 59(2), 569‒590.

14. Mann, A. I., Patience, R. I., Poplett, I. J. F. Determination of molecular structure of kerogens using 13C NMR spectroscopy: I. The effects of variation in kerogen type. Geochim. Cosmochim. Acta, 1991, 55(8), 2259‒2268.

15. Lille, Ü., Heinmaa, I., Müürisepp, A. M., Pehk, T. Investigation of kukersite structure using NMR and oxidative cleavage: On the nature of phenolic precursors in the kerogen of Estonian kukersite. Oil Shale, 2002, 19(2), 101‒116.

16. Tong, J. H., Han, X. X., Wang, S., Jiang, X. M. Evaluation of structural characteristics of Huadian oil shale kerogen using direct techniques (solid-state 13C NMR, XPS, FT-IR, and XRD). Energy Fuels, 2011, 25(9), 4006‒4013.

17. Orendt, A. M., Pimienta, I. S. O., Badu, S. R., Solum, M. S., Pugmire, R. J., Facelli, J. C., Locke, D. R., Chapman, K. W., Chupas, P. J., Winans, R. E. Three-dimensional structure of the Siskin Green River oil shale kerogen model: A comparison between calculated and observed properties. Energy Fuels, 2013, 27(2), 702‒710.

18. Ungerer, P., Collell, J., Yiannourakou, M. Molecular modeling of the volumetric and thermodynamic properties of kerogen: Influence of organic type and maturity. Energy Fuels, 2015, 29(1), 91‒105.

19. Guan, X. H., Liu, Y., Wang, D., Wang, Q., Chi, M. S., Liu, S., Liu, C. G. Three-dimensional structure of a Huadian oil shale kerogen model: An experimental and theoretical study. Energy Fuels, 2015, 29(7), 4122-4136.

20. Tong, J. H., Jiang, X. M., Han, X. X., Wang, X. Y. Evaluation of the macromolecular structure of Huadian oil shale kerogen using molecular modeling. Fuel,2016, 181, 330‒339.

21. Katti, D. R., Thapa, K. B., Katti, K. S. Modeling molecular interactions of sodium montmorillonite clay with 3D kerogen models. Fuel, 2017, 199, 641‒652.

22. Rogel, E. Simulation of interactions in asphaltene aggregates. Energy Fuels, 2000, 14(3), 566‒574.

23. Wind, R. A., Maciel, G. E., Botto, R. E. Quantitation in 13C NMR spectroscopy of carbonaceous solids. In: Magnetic Resonance of Carbonaceous Solids(Botto, R. E., Sanada, Y., eds.), Advances in Chemistry, 229. American Chemical Society, Washington, DC, 1992, 3‒26.

24. Miknis, F. P. Applications of solid-state NMR in oil shale research. In: Annual Reports on NMR Spectroscopy33. Academic Press, 1996, 207‒246.

25. Smernik, R. J., Oades, J. M. The use of spin counting for determining quantitation in solid state 13C NMR spectra of natural organic matter 1. Model systems and the effects of paramagnetic impurities. Geoderma, 2000, 96(1‒2), 101‒129.

26. Snape, C. E., Axelson, D. E., Botto, R. E., Delpuech, J. J., Tekely, P., Gerstein, B. C., Pruski, M., Maciel, G. E., Wilson, M. A. Quantitative reliability of aromaticity and related measurements on coals by 13C n.m.r. A debate. Fuel, 1989, 68(5), 547‒548.

27. Smernik, R. J., Schwark, L., Schmidt, M. W. I. Assessing the quantitative reliability of solid-state 13C NMR spectra of kerogens across a gradient of thermal maturity. Solid State Nucl. Magn. Reson., 2006, 29(4), 312‒321.

28. Mao, J. D., Cao, X. Y., Olk, D. C., Chu, W. Y., Schmidt-Rohr, K. Advanced solid-state NMR spectroscopy of natural organic matter. Prog. Nucl. Magn. Reson. Spectrosc., 2017, 100, 17‒51.

29. Botto, R. E., Wilson, R., Winans, R. E. Evaluation of the reliability of solid 13C-NMR spectroscopy for the quantitative analysis of coals: Study of whole coals and maceral concentrates. Energy Fuels, 1987, 1(2), 173‒181.

30. Fang, X. W., Chua, T., Schmidt-Rohr, K., Thompson, M. L. Quantitative 13C NMR of whole and fractionated Iowa Mollisols for assessment of organic matter composition. Geochim. Cosmochim. Acta, 2010, 74(2), 584‒598.

31. Mao, J. D., Fang, X. W., Lan, Y. Q., Schimmelmann, A., Mastalerz, M., Xu, L.,  Schmidt-Rohr, K. Chemical and nanometer-scale structure of kerogen and its change during thermal maturation investigated by advanced solid-state 13C NMR spectroscopy. Geochim. Cosmochim. Acta, 2010, 74(7), 2110‒2127.

32. Gao, Y., Zou, Y. R., Liang, T., Peng, P. A. Jump in the structure of Type I kerogen revealed from pyrolysis and 13C DP MAS NMR. Org. Geochem., 2017, 112, 105‒118.

33. Maroto-Valer, M. M., Taulbee, D. N., Andrésen, J. M., Hower, J. C., Snape, C. E. Quantitative 13C NMR study of structural variations within the vitrinite and inertinite maceral groups for a semifusinite-rich bituminous coal. Fuel, 1998, 77(8), 805‒813.

34. Mao, J. D., Hu, W. G., Schmidt-Rohr, K., Davies, G., Ghabbour, E. A., Xing, B. Quantitative characterization of humic substances by solid-state carbon-13 nuclear magnetic resonance. Soil Sci. Soc. Am. J., 2000, 64(3), 873‒884.

35. Durand, B., Nicaise, G. Procedures for kerogen isolation. In: Kerogen-Insoluble Organic Matter from Sedimentary Rocks (Durand, B., ed.). Editions Technip, Paris, 1980, 35–53.

36. Massiot, D., Fayon, F., Capron, M., King, I., Le Calvé, S., Alonso, B., Durand, J.-O., Bujoli, B., Gan, Z., Hoatson, G. Modelling one- and two-dimensional solid-state NMR spectra. Magn. Reson. Chem., 2002, 40(1), 70‒76.

37. You, Y. L., Han, X. X., Liu, J. G., Jiang, X. M. Structural characteristics and pyrolysis behaviors of Huadian oil shale kerogens using solid-state 13C NMR, Py-GCMS and TG. J. Therm. Anal. Calorim., 2018, 131(2), 1845‒1855.

38. Ru, X., Cheng, Z., Song, L., Wang, H., Li, J. Experimental and computational studies on the average molecular structure of Chinese Huadian oil shale kerogen. J. Mol. Struct., 2012, 1030, 10‒18.

39. Siskin, M., Scouten, C. G., Rose, K. D., Aczel, T., Colgrove, S. G., Pabst Jr., R. E. Detailed structural characterization of the organic material in Rundle Ramsay Crossing and Green River oil shales. In: Composition, Geochemistry and Conversion of Oil Shales (Snape, C., ed.), NATO ASI Series, 455, Springer Netherlands, 1995, 143‒158.

40. Huang, Y. R., Han, X. X., Jiang, X. M. Characterization of Dachengzi oil shale fast pyrolysis by Curie-point pyrolysis-GC-MS. Oil Shale, 2015, 32(2), 134‒150.

41. Solum, M. S., Pugmire, R. J., Grant, D. M. Carbon-13 solid-state NMR of Argonne-premium coals. Energy Fuels, 1989, 3(2), 187‒193.

42. Huang, Y. R., Han, X. X., Jiang, X. M. Comparison of fast pyrolysis characteristics of Huadian oil shales from different mines using Curie-point pyrolysis-GC/MS. Fuel Process. Technol., 2014, 128, 456‒460.

43. Razvigorova, M., Budinova, T., Tsyntsarski, B., Petrova, B., Ekinci, E., Atakul, H. The composition of acids in bitumen and in products from saponification of kerogen: Investigation of their role as connecting kerogen and mineral matrix. Int. J. Coal Geol., 2008, 76(3), 243‒249.

44. Wind, R. A., Duijvestijn, M. J., van der Lugt, C., Smidt, J., Vriend, H. An investigation of coal by means of e.s.r., 1H n.m.r., 13C n.m.r. and dynamic nuclear polarization. Fuel, 1987, 66(7), 876‒885.

45. Cao, X. Y., Birdwell, J. E., Chappell, M. A., Li, Y., Pignatello, J. J., Mao, J. D. Characterization of oil shale, isolated kerogen, and post-pyrolysis residues using advanced 13C solid-state nuclear magnetic resonance spectroscopy. AAPG Bull., 2013, 97(3), 421‒436.

46. Veeman, W. S. Carbon-13 chemical shift anisotropy. Prog. Nucl. Magn. Reson. Spectrosc., 1984, 16, 193‒235.

47. Snape, C. E., McGhee, B. J., Martin, S. C., Andresen, J. M. Structural characterisation of catalytic coke by solid-state 13C-NMR spectroscopy. Catal. Today,1997, 37(3), 285‒293.

Back to Issue