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Chemistry of lignite liquefaction. Quarterly report, October--December 1977. [Model compounds]

Technical Report ·
DOI:https://doi.org/10.2172/6609718· OSTI ID:6609718

Solvent refined lignite (SRL), obtained by treating lignite with carbon monoxide-hydrogen-water at 1,500 to 2,500 psi at ca. 400/sup 0/C, has an average molecular weight of ca. 460 with about 89 percent carbon, 6 percent hydrogen, 3 percent oxygen, 1 percent nitrogen and 1 percent sulfur with no inorganic material. Based on nuclear magnetic resonance studies, SRL is highly aromatic and one acid group and 0.1 base groups per average molecule. SRL is similar to solvent refined coal (SRC's) from bituminous and subbituminous coals in C, H, and S elemental analysis, acid content, nmr and uv spectra, but lower in nitrogen and base content. Gel permeation chromatographic separations, using pyridine as the eluant, show the range of molecular weights of SRL to be 4000 to 160 gm/mole. As determined by X-ray diffraction studies, SRL and SRC have crystallites present in the solid phase with about 15A diameter with the SRL having an average stack of four aromatic planes separated by 3.7A. Low angle X-ray scattering studies on the SRL sample in pyridine solution showed the molecules to have an 18A average radius of gyration. Solvent refined lignite can be 90 percent converted by catalytic hydrogenation into ca. 20 percent light liquids, 15 percent light oil, 20 percent heavy oil and gases. Phenol, ethylbenzene, diphenylether, diphenylmethane, dibenzothiophene and carbazole are difficult to reduce under carbon monoxide-water conditions at 425/sup 0/C in batch autoclaves. For all but the quinoline reaction, where hydrogen was superior, a blend of carbon monoxide-water and hydrogen was the optimum set of reducing gases. Carbon monoxide and water outperformed hydrogen for the benzophenone and benzhydrol reductions. A host of metal oxides (possible in situ catalysts in coal) has been tested by electron spin resonance for activity in electron transfer processes.

Research Organization:
North Dakota Univ., Grand Forks (USA)
OSTI ID:
6609718
Report Number(s):
FE-2211-8
Country of Publication:
United States
Language:
English