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Chemistry and structure of coal-derived asphaltenes, Phase III. Quarterly progress report, July--September 1978

Technical Report ·
DOI:https://doi.org/10.2172/6090235· OSTI ID:6090235
Preparative scale GPC separation of Synthoil asphaltene was carried out on styrene-divinyl benzene packing (Bio-Beads S-X8). The elution took place in the order of high to low molecular weight. Analyses indicate that aromatic ring systems with large saturated substituents elute first followed by more aromatic molecules with less saturated substituents. Infrared measurements on coal-derived asphaltenes were carried out with a large path cell (1 cm) in order to measure absorbance as a function of concentration in dilute solution down to 0.3 g/l where association between asphaltenes is not significant. VPO molecular weight studies indicate that coal-derived oils and resins undergo very little association in the solvent THF in the range 4 to 30 g/l in contrast to coal-derived asphaltenes and benzene insolubles. Thermal treatment of a Synthoil Coal liquid solvent fraction (oil + resin), in tetralin (1:2 wt. ratio) at 232/sup 0/C for 20 h resulted in the transformation of 3 to 10% of the oil + resin into asphaltene. These results support the proposed reversibility of coal liquefaction steps. Pryolysis of coal-derived asphaltenes has been shown to produce residues that are characteristic of coalesced mesophase. Asphaltenes from three liquefaction processes, Catalytic Incorporatd SRC, Synthoil, and FMC-COED, were pyrolyzed under a nitrogen atmosphere at 20/sup 0/C/h to 360/sup 0/C and at 5/sup 0/C/h to 420/sup 0/C. Crossed polarized light reflection micrographs showed a coarse deformed structure for Synthoil asphaltene, a course, but not deformed structure for Catalytic Inc. asphaltne, and a fine isotropic structure for FMC-COED asphaltene.
Research Organization:
University of Southern California, Los Angeles (USA)
Sponsoring Organization:
USDOE
OSTI ID:
6090235
Report Number(s):
FE-2031-13
Country of Publication:
United States
Language:
English