Comparison of Coal-Derived and Petroleum Asphaltenesby 13 C Nuclear Magnetic Resonance, DEPT, and XRS (original) (raw)

Abstract

The molecular architecture of asphaltenes is still a matter of debate. Some literature reports provide evidence that the contrast of petroleum asphaltenes versus coal-derived asphaltenes is useful for understanding the governing principles of asphaltene identity. Coal-derived asphaltenes provide an excellent test for understanding the relationship of asphaltene molecular architecture with asphaltene properties. Diffusion measurements have shown that coal-derived asphaltenes are half the size of many crude oil asphaltenes, but there are relatively few studies comparing coal-derived and petroleum asphaltenes using liquid state 13 C NMR. 13 C NMR confirms that the molecular sizes of these coal-derived asphaltenes are smaller than virgin petroleum asphaltenes. DEPT-45 experiments were performed in order to determine the relative amount of nonprotonated and protonated carbon in the aromatic region of the spectrum. In contrast to previous NMR work on asphaltenes that ignored interior bridgehead carbon, we show this is an important component of asphaltenes and that correctly accounting for this carbon enables proper determination of the number of fused rings. XRS data supports interpreting the NMR data with a model that weighs circularly condensed structures more heavily than linearly condensed structures. Significantly more carbon exists in chains at least 9 carbons long in petroleum asphaltenes (g7%) compared to coal-derived asphaltenes (g1%). .

Figures (10)

Table 1. Elemental Composition and Yield for Coal-Derived Asphaltenes and Petroleum-Derived Asphaltenes

Table 1. Elemental Composition and Yield for Coal-Derived Asphaltenes and Petroleum-Derived Asphaltenes

Table 2. Chemical Shifts and Integration Limits for Evaluat- ing the Aromatic and Aliphatic Contributions

Table 2. Chemical Shifts and Integration Limits for Evaluat- ing the Aromatic and Aliphatic Contributions

Figure 1. Aliphatic portion of the **C NMR spectra for three CD- asphaltene samples (TH-A, WY-A, AD-A) and two P-asphaltenes (BGS, UGS8). Table 3 lists the aliphatic wt % obtained using chemical shifts specified in Table 2. The peaks labeled a, /, y, 0, and € arise from terminal carbons (, 14 ppm), and carbons that are 1 (3, 22.7 ppm), 2 (y,32 ppm), 3 (6, 29.7 ppm), and 4 (¢, 30.1 ppm) or more carbons away from the terminal carbon. The n-paraflin wt % is obtained by integrating these peaks.

Figure 1. Aliphatic portion of the **C NMR spectra for three CD- asphaltene samples (TH-A, WY-A, AD-A) and two P-asphaltenes (BGS, UGS8). Table 3 lists the aliphatic wt % obtained using chemical shifts specified in Table 2. The peaks labeled a, /, y, 0, and € arise from terminal carbons (, 14 ppm), and carbons that are 1 (3, 22.7 ppm), 2 (y,32 ppm), 3 (6, 29.7 ppm), and 4 (¢, 30.1 ppm) or more carbons away from the terminal carbon. The n-paraflin wt % is obtained by integrating these peaks.

Figure 2. Aromatic portion of the “C NMR spectra for three CD- asphaltene samples (TH-A, AD-A, WY-A) and two P-asphaltenes (BGS, UG8). Table 3 lists the aromatic wt % obtained by integration using the chemical shifts specified in Table 2. The P-asphaltenes have roughly 50% aromatic carbon whereas the CD-asphaltenes are close to 80% aromatic carbon.

Figure 2. Aromatic portion of the “C NMR spectra for three CD- asphaltene samples (TH-A, AD-A, WY-A) and two P-asphaltenes (BGS, UG8). Table 3 lists the aromatic wt % obtained by integration using the chemical shifts specified in Table 2. The P-asphaltenes have roughly 50% aromatic carbon whereas the CD-asphaltenes are close to 80% aromatic carbon.

Table 3. '*C NMR Results for Coal-Derived Asphaltenes: AD and TH are Indonesian Coals, WY is a U.S. Coal, and BGS and UG8 are Both Middle Eastern Petroleum Asphaltenes

Table 3. '*C NMR Results for Coal-Derived Asphaltenes: AD and TH are Indonesian Coals, WY is a U.S. Coal, and BGS and UG8 are Both Middle Eastern Petroleum Asphaltenes

Figure 5. Plot showing the mole fraction of bridgehead carbons vs the number of carbons per aromatic cluster. The dashed curves are the two limits of circular (upper) and linear (lower) concatenation. The solid line is a best fit of the dependence of y;, on C (for further explanation see ref 23; reproduced with permission of the publisher).

Figure 5. Plot showing the mole fraction of bridgehead carbons vs the number of carbons per aromatic cluster. The dashed curves are the two limits of circular (upper) and linear (lower) concatenation. The solid line is a best fit of the dependence of y;, on C (for further explanation see ref 23; reproduced with permission of the publisher).

Figure 6. Carbon K-edge XRS spectra of three model compounds and UG8 and TH-A asphaltenes. 1s-7* and 1s-o* transitions are observed as indicated.

Figure 6. Carbon K-edge XRS spectra of three model compounds and UG8 and TH-A asphaltenes. 1s-7* and 1s-o* transitions are observed as indicated.

Figure 3. Comparison of the normal quantitative '*C SPE and DEPT45 spectra for the P-asphaltene sample UG8. Quantitative SPE under- estimates the bridgehead carbon by S0O—90%. Figure 4. Comparison of the normal quantitative '*C SPE and DEPT45 spectra for the CD-asphaltene sample AD-A. Quantitative SPE under- estimates the bridgehead carbon by S0O—90%.

Figure 3. Comparison of the normal quantitative '*C SPE and DEPT45 spectra for the P-asphaltene sample UG8. Quantitative SPE under- estimates the bridgehead carbon by S0O—90%. Figure 4. Comparison of the normal quantitative '*C SPE and DEPT45 spectra for the CD-asphaltene sample AD-A. Quantitative SPE under- estimates the bridgehead carbon by S0O—90%.

Loading...

Loading Preview

Sorry, preview is currently unavailable. You can download the paper by clicking the button above.

References (72)

  1. Mullins, O. C., Sheu, E. Y., Hammami, A., Marshall, A. G., Eds.
  2. Asphaltenes, Heavy Oils and Petroleomics; Springer: New York, 2007.
  3. Groenzin, H.; Mullins, O. C. Molecular sizes of asphaltenes from different origin. Energy Fuels 2000, 14, 677.
  4. Buenrostro-Gonzalez, E.; Groenzin, H.; Lira-Galeana, C.; Mullins, O. C. The overriding chemical principles that define asphaltenes. Energy Fuels 2001, 15, 972.
  5. Badre, S; Goncalves, C. C.; Norinaga, K; Gustavson, G; Mullins, O. C. Molecular size and weight of asphaltene and asphaltene solubility fractions from coals, crude oils and bitumen. Fuel 2006, 85, 1.
  6. Wargadalam, V. J.; Norinaga, K.; Iino, M. Size and shape of a coal asphaltene studied by viscosity and diffusion coefficient measurements. Fuel 2002, 81, 1403.
  7. Freed, D. E. Lisitza, N. V. Sen, P. N. Song, Y.-Q. Asphaltene molecular composition and dynamics from NMR diffusion measure- ments. Ch. 11 in Asphaltenes, Heavy Oils and Petroleomics; Mullins, O. C., Sheu, E. Y., Hammami, A., Marshall, A. G., Eds.; Springer: New York, 2007.
  8. Andrews, A. B.; Guerra, R.; Sen, P. N.; Mullins, O. C. J. Phys. Chem. A 2006, 110, 8095.
  9. Schneider, M. H.; Andrews, A. B.; Mitra-Kirtley, S.; Mullins, O. C. Asphaltene Molecular Size by Fluorescence Correlation Spectros- copy. Energy Fuels 2007, 21 (5), 2875-2882.
  10. Guerra, R.; Andrews, A. B.; Mullins, O. C.; Sen, P. N. Compar- ison of asphaltene molecular diffusivity of various asphaltenes by fluorescence correlation spectroscopy. Fuel 2007, 86, 2016-2020.
  11. Boduszynski, M. M. Ch. 7 in Chemistry of Asphaltenes; Bunger, J. W., Li, N.C., Eds.; American Chemical Society: Washington, DC, 1981.
  12. Zhan, D.; Fenn, J. B. Electrospray mass spectrometry of fossil fuels. Int. J. Mass Spectrom. 2000, 194, 197-208.
  13. Rodgers, R. P.; Marshall, A. G. Petroleomics: Advanced Char- acterization of Petroleum Derived Materials by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS). Ch. 3 in Asphal- tenes, Heavy Oils and Petroleomics;
  14. Mullins, O. C., Sheu, E. Y., Hammami, A., Marshall, A. G., Eds.; Springer: New York, 2007
  15. Klein, G. C.; Kim, S.; Rodgers, R. P.; Marshall, A. G.; Yen, A.; Asomaning, S. Mass Spectral Analysis of Asphaltenes. I. Compositional Differences between Pressure-Drop and Solvent-Drop Asphaltenes Determined by Electrospray Ionization Fourier Transform Ion Cyclo- tron Resonance Mass Spectrometry. Energy Fuels 2006, 20, 1965-1972.
  16. Martinez-Haya, B.; Hortal, A. R.; Hurtado, P. M.; Mullins, O. C. Molecular weight distributions of coal and petroleum asphaltenes from laser desorption ionization experiments. Energy Fuels 2007, 21, 2863-2868.
  17. Pomerantz, A. E.; Hammond, M. R.; Morrow, A. L.; Mullins, O. C.; Zare, R. N. Two-Step Laser Mass Spectrometry of Asphaltenes. J. Am. Chem. Soc. 2008, 130, 7216-7217.
  18. Pomerantz, A. E.; Hammond, M. R.; Morrow, A. L.; Mullins, O. C.; Zare, R. N. Asphaltene Molecular Weight Distribution Deter- mined by Two-Step Laser Mass Spectrometry. Energy Fuels 2009, 23, 1162-1168.
  19. Sabbah, H; Morrow, A. L.; Pomerantz, A. E.; Zare, R. N. Evidence for island structures as the dominant architecture of asphal- tenes. Energy Fuels 2011, 25, 1597-1604.
  20. Rodgers, R. P.; Tan, X.; Ehrmann, B. M.; Juyal, P.; McKenna, A. M.; Purcell, J. M.; Schaub, T. M.; Gray, M. R.; Marshall, A. G. Asphaltene Structure Determined by Mass Spectrometry. 9th Interna- tional Conference on Petroleum Phase Behavior & Fouling, Victoria, B. C., Canada, 15À19 June, 2008; Abstract 102.
  21. Borton, D., II; Pinkston, D. S.; Hurt, M. R.; Tan, X.; Azyat, K.; Tykwinski, R.; Gray, M.; Qian, K.; Kentt€ amaa, H. I. Molecular Structures of Asphaltenes Based on the Dissociation Reactions of Their Ions in Mass Spectrometry. Energy Fuels 2010, 24, 5548-5559.
  22. Ruiz-Morales, Y.; Mullins, O. C. Polycyclic Aromatic Hydro- carbons of Asphaltenes Analyzed by Molecular orbital Calculations with Optical Spectroscopy. Energy Fuels 2007, 21, 256.
  23. Andrews, A. B.; McClelland, A.; Korkeila, O.; Demidov, A.; Krummel, A.; Mullins, O. C.; Chen, Z. Molecular Orientation of Asphaltenes and PAH Model Compounds in Langmuir-Blodgett Films Using Sum Frequency Generation Spectroscopy. Langmuir 2011, 27 (10), 6049-6058.
  24. Buch, L; Groenzin, H; Buenrostro-Gonzalez, E; Andersen, S. I.; Lira-Galeana, C; Mullins, O. C. Effect of hydrotreatment on asphaltene fractions. Fuel 2003, 82, 1075-84.
  25. Solum, M. S.; Pugmire, R. J.; Grant, D. M. 13 C Solid-State NMR of Argonne Premium Coals. Energy Fuels 1989, 3, 187-193.
  26. Solum, M. S.; Sarofim, A. F.; Pugmire, R. J.; Fletcher, T. H.; Zhang, H. 13 C NMR Analysis of Soot Produced from Model Com- pounds and a Coal. Energy Fuels 2001, 15, 961-971.
  27. Pugmire, R. J.; Solum, M. S.; Grant, D. M.; Critchfield, S.; Fletcher, T. H. Structural Evolution of Matched Tar-Char Pairs in Rapid Pyrolysis Experiments. Fuel 1991, 70, 414.
  28. Siskin, M.; Kelemen, S. R.; Eppig, C. P.; Brown, L. D.; Afeworki, M. Asphaltene Molecular Structure and Chemical Influences on the Morphology of Coke Produced in Delayed Coking. Energy Fuels 2006, 20, 1227-1234.
  29. 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;
  30. Vandenbroucke, R. J. M.; Leblond, M.; Behar, F. Direct Characterization of Kerogen by X-Ray and Solid-State 13 C Nuclear Magnetic Resonance Methods. Energy Fuels 2007, 21, 1548- 1561.
  31. Fletcher, T. H.; Kerstein, A. R.; Pugmire, R. J.; Solum, M. S.; Grant, D. M. Chemical Percolation Model for Devolatilization. 3. Direct Use of 13 C NMR Data to Predict Effects of Coal Type. Energy Fuels 1992, 6, 414-431.
  32. Sheremata, J. M.; Gray, M. R.; Dettman, H. D.; McCaffrey, W. C. Quantitative Molecular Representation and Sequential Optimiza- tion of Athabasca Asphaltenes. Energy Fuels 2004, 18, 1377-1384.
  33. Michon, L.; Martin, D.; Planche, J.-P.; Hanquet, B. Estimation of average molecule parameters of bitumens by 13 C nuclear magnetic resonance spectroscopy. Fuel 1997, 76, 9-15.
  34. Japanwala, S.; Chung, K. H.; Dettman, H. D.; Gray, M. R. Quality of Distillates from Repeated Recycle of Residue. Energy Fuels 2002, 16, 477-484.
  35. Christopher, J.; Sarpal, A. S.; Kapur, G. S.; Krishna, A.; Tyagi, B. R.; Jain, M. C.; Jain, S. K.; Bhatnagar, A. K. Chemical Structure of Bitumen-Derived Asphaltenes by Nuclear Magnetic Resonance Spec- troscopy and X-Ray Diffractometry. Fuel 1996, 75, 999-1008.
  36. Hirano, K. Outline of NEDOL coal liquefaction process devel- opment (pilot plant program). Fuel Process. Technol. 2000, 62 (2À3), 109-118.
  37. Ikeda, K.; Sakawaki, K.; Nogami, Y.; et al. Kinetic evaluation of progress in coal liquefaction in the 1 t/d PSU for the NEDOL process. Fuel 2000, 79 (3À4), 373-378.
  38. Boduszynski, M. M.; Altgelt, K. H. Composition and Analysis of Heavy Petroleum Fractions; Marcel Dekker: New York, 1994.
  39. Bartle, K. D.; Ladner, W. R.; Martin, T. G.; Snape, C. E.; Williams, D. F. Structural Analysis of supercritical gas extracts of coals. Fuel 1979, 58, 413-422.
  40. Maekawa, Y.; Yoshida, T.; Yoshida, Y. Quantitative 13 C NMR Spectroscopy of a coal derived oil and the assignment of chemical shifts. Fuel 1979, 58, 864-972.
  41. Abu-Dagga, F.; Ruegger, H. Evaluation of low boiling crude oil fractions by NMR spectroscopy. Average Structural Parameters and identification of aromatic components by 2D NMR Specroscopy. Fuel 1988, 67, 1255-1262.
  42. Friebolin, H. Basic One-and Two-Dimensional NMR Spectros- copy;
  43. Wiley-VCH, 1991; pp 192À197.
  44. Netzel, D. A. Quantification of carbon types using DEPT/ QUAT NMR pulse sequences: Application to fossil fuel derived oils. Anal. Chem. 1987, 59, 1775.
  45. Netzel, D. A.; Guffey, E. D. NMR and GC/MS Investigation of the Saturate Fraction from the Cerro Negro Heavy Petroleum Crude. Energy Fuels 1989, 3, 455-460.
  46. Behera, B.; Ray, S. S.; Singh, I. D. Structural Characterization of FCC Feeds from Indian Refineries by NMR Spectroscopy. Fuel 2008, 87, 2322-2333.
  47. Cookson, D. J.; Smith, B. E. Quantitative Estimation of CHn Group Abundances in Fossil Fuel Materials using 13 C NMR Methods. Fuel 1983, 62, 986-988.
  48. Dereppe, J. M.; Moreux, C. Measurement of CH n Group Abundances in Fossil Fuel Materials using DEPT 13 C NMR. Fuel 1985, 64, 1174-1176.
  49. Jiang, B.; Xiao, N.; Liu, H.; Zhou, Z.; Mao, X. A.; Liu, M. Optimized Quantitative DEPT and Quantitative POMMIE Experi- ments for 13 C NMR. Anal. Chem. 2008, 80, 8293-8298.
  50. Montanari, L.; Montani, E.; Corno, C.; Fattori, S. NMR Molecular Characterization of Lubricating Base Oils: Correlation with Their Performance. Appl. Magn. Reson. 1998, 14, 345-356.
  51. Diaz, C.; Blanco, C. G. NMR: A Powerful Tool in the Char- acterization of Coal tar Pitch. Energy Fuels 2003, 17, 907-913.
  52. Morgan, T. J.; George, A.; Davis, D. B.; Herod, A. A.; Kandiyoti, R. Optimization of 1 H and 13 C NMR Methods for Structural Char- acterization of Acetone and Pyridine Soluble Fractions of a Coal tar Pitch. Energy Fuels 2008, 22, 1824-1835.
  53. Masuda, K.; Okuma, O.; Nishizawa, T.; Kanaji, M.; Matsumura, T. High Temperature NMR Analysis of Aromatic Units in Asphaltenes and Preasphaltenes Derived from Victorian Brown Coal. Fuel 1996, 75, 295-299.
  54. Begon, V.; Suelves, I.; Islas, C. A.; Millan, M.; Dubau, C.; Lazaro, M.-J.; Law, R. V.; Herod, A. A.; Dugwell, D. R.; Kandiyoti, R. Comparison of Quaternary Aromatic Carbon Contents of a Coal, a Coal Extract, and its Hydrocracking Products by NMR Methods. Energy Fuels 2003, 17, 1616-1629.
  55. Bergmann, U.; Groenzin, H.; Mullins, O. C.; Glatzel, P.; Fetzer, J.; Cramer, S. P. Carbon K-edge X-ray Raman spectroscopy supports simple, yet powerful description of aromatic hydrocarbons and asphal- tenes. Chem. Phys. Lett. 2003, 369, 184-191.
  56. Bergmann, U.; Glatzel, P.; Cramer, S. P. Bulk-sensitive XAS characterization of light elements: from X-ray Raman scattering to X-ray Raman spectroscopy. Microchem. J. 2002, 71, 221-230.
  57. Waber, J. T.; Cromer, D. T. Orbital Radii of Atoms and Ions.
  58. J. Chem. Phys. 1965, 42, 4116-4123.
  59. St€ ohr, J. NEXAFS Spectroscopy; Springer: Berlin, 1992; p 403.
  60. Sharma, A.; Groenzin, H.; Mullins, O. C.; Tomita, A. Probing order in asphaltenes and aromatic ring systems by HRTEM. Energy Fuels 2002, 16 (2), 490.
  61. Bergmann, U.; Groenzin, H.; Mullins, O. C.; Glatzel, P.; Fetzer, J.; Cramer, S. P. X-Ray Raman Spectroscopy--A New Tool to Study Local Structure of Aromatic Hydrocarbons and Asphaltenes. Pet. Sci. Technol. 2004, 22, 863-875.
  62. Clar, E. The Aromatic Sextet; John Wiley & Sons: London, 1972; p 128.
  63. Gould, K. A.; Wiehe, I. A. Natural Hydrogen Donors in Petroleum Resids. Energy Fuels 2007, 21, 1199-1204.
  64. Artok, L.; Su, Y.; Hirose, Y.; Hosokawa, M.; Murata, S.; Nomura, M. Structure and Reactivity of Petroleum-Derived Asphaltenes. Energy Fuels 1999, 13, 287-296.
  65. Sharma, B. K.; Adhvaryu, A.; Perez, J. M.; Erhan, S. Z. Effects of hydro-processing on structure and properties of base oils using NMR. Fuel Proc. Technol. 2008, 89, 984.
  66. Mojelsky, T. W.; Ignasiak, T. M.; Frackman, Z.; McIntyre, D. D.; Lown, E. M.; Montgomery, D. S.; Strausz, O. P. Structural Features of Alberta Oil Sand Bitumen and Heavy Oil Asphaltenes. Energy Fuels 1992, 6, 83-96.
  67. Su, Y.; Artok, L.; Murata, S.; Nomura, M. Structual Analysis of the Asphaltene Fraction of an Arabian Mixture by a Ruthenium-Ion- Catalyzed Oxidation Reaction. Energy Fuels 1998, 12, 1265-1271.
  68. Strausz, O. P.; Mojelsky, T. W.; Faraji, F.; Lown, E. M.; Peng, P. a. Additional Structural Details on Athabasca Asphaltene and Their Ramifications. Energy Fuels 1999, 13, 207-227.
  69. Lehne, E.; Dieckmann, V. Improved understanding of mixed oil in Nigeria based on pyrolysis of asphaltenes. Org. Geochem. 2010, 41, 661-674.
  70. Cyr, N.; McIntyre, D. D.; Toth, G.; Strausz, O. P. Hydrocarbon structural group analysis of Athabsca asphaltene and its g.p.c. fractions by
  71. C NMR. Fuel 1987, 66, 1709-1714.
  72. Dittmar, T.; Koch, B. P. Thermogenic organic matter dissolved in the abyssal ocean. Mar. Chem. 2006, 102, 208-217.