Energy & Fuels 1988,2, 170-175
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pyridine. Unless such extracts are well protected from air oxidation and clarified by membrane filtration or ultracentrifugation, the extracts contain colloidal material. With attention to anaerobic conditions and solvent purity, extraction can reliably produce extracts characteristic of the original coal. Extract yield and molecular size of the extracts increase with the swelling ability of the solvent for the coal in question. For Illinois coals, air oxidation at room temperature decreases total extract yield and the average molecular size of most of the extracts. The reactive material in extracts of fresh coal is not present in extracts of oxidized coals. Pyridine and DMF are tightly bound to coals, extracts, and residues but can be removed by
washing with 80% (v/v) methanol/water, a solvent mixture with both a large heat of immersion and a high wetting rate for coal surfaces.
Acknowledgment. We thank the Illinois Coal Development Board for financial support provided through the Center for Research on Sulfur in Coal, Dr. Carl W. Kruse, Illinois State Geological Survey, and Dr. Karl Vorres, Argonne National Laboratory, for coal samples; Dr. R. Malhotra, SRI International, for FIMS spectra; and a reviewer for helpful comments. Registry No. THF, 109-99-9;DMF,68-12-2; C6H,CH3,10888-3; pyridine, 110-86-1.
Hydrocarbon Characterization of Resinitef R. J. Hwang* and S . C. Teerman Chevron Oil Field Research Company, P.O. Box 446, La Habra, California 90633-0446 Received August 24, 1987. Revised Manuscript Received October 16, 1987
Resinites were pyrolyzed by using both closed- and open-flow-systempyrolysis techniques to evaluate their generative potential. The composition of generated products and the temperature of thermal breakdown of the resinite are dependent on the pyrolysis process. Differences between closed- and open-system pyrolysis are explained by detailed pyrolyzate anlaysis and chemical processes involved in the different pyrolysis techniques. Hydrous pyrolysis most closely simulates the natural process of hydrocarbon generation, including the temperature of generation and the composition of generated products. Open-system pyrolysis data can lead to the erroneous conclusion that resinite generates significant quantities of hydrocarbons at low temperatures. Hydrous pyrolysis experiments on pure resinites indicate that generation of liquid hydrocarbons occurs at similar or slightly higher levels of thermal maturity than for most other kinds of oil-prone kerogen. Characterization of hydrous pyrolysis residues with fluorescence microscopy, infrared spectroscopy, and elemental analyses also indicates that resinite does not generate liquid hydrocarbons at thermally immature levels. Oil pyrolyzates, generated at various temperatures, are light and nonpardfinic, consisting predominantly of cyclic isoprenoids and their aromatic derivatives. Minor amounts of naphthenic components also are present. The composition of generated products differs with resinite precursor. The resinite pyrolyzates are chemically distinct from most naturally occurring oils. The dissimilarity of these pyrolyzates to natural oils suggests that resinite is not an important source of petroleum.
Introduction
As a maceral, resinite usually originates from terrestrial plant and tree resins and occurs in coals and other sedimentary rocks, usually as a minor component (
