Subfractionation and Characterization of Mayan Asphaltene
| Autor: | Jeffrey T. Miller, Jerry E. Hunt, and R. E. Winans, Pappannan Thiyagarajan, R. B. Fisher |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Energy & Fuels. 12:1290-1298 |
| ISSN: | 1520-5029 0887-0624 |
| DOI: | 10.1021/ef9800664 |
| Popis: | Mayan crude, residuum, and hydrocracked asphaltenes have been separated into two fractions by extended Soxhlet extraction in n-heptane. Although the solubility, composition, and molecular structures differ slightly, the greatest difference between the two asphaltene fractions is the degree to which they associate in solution. The vapor-phase osmometry molecular weight, molecular size by size-exclusion chromatography, and small-angle neutron scattering indicate that approximately 25% of Mayan asphaltene is not highly associated in aromatic solvents and, thus, is noncolloidal. By contrast, the remaining asphaltene forms large, rodlike colloidal particles in solution and has a higher apparent molecular weight. Although laser desorption mass spectrometry indicates that the molecular weight of the individual molecules in maltenes and asphaltenes is not very different, high-resolution mass spectrometry indicates that the size of the aromatic core of asphaltenes is significantly larger than those in maltenes. Fu... |
| Databáze: | OpenAIRE |
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