Mobile Phase in Coals: Its Nature and Modes of Release: A Study of the Molybdenum Catalyzed Hydrogenation of Coals in the Absence of Solvent: Final Report, Part 3

摘要

Several coals of different rank were hydrogenated using an impregnated molybdenum catalyst. It was found that the generation of chloroform-soluble extracts and gases from low-rank coals occurred much more readily than for higher rank coals. Reaction of a low-volatile bituminous coal produced only a low level of soluble products, even in the presence of an active hydrogenating catalyst. The reactivity of the coals attests to the known differences in coal structure. That is, coals of low rank consist of structural units which are less condensed and more aliphatic and are joined by a higher proportion of weak cross-links than coals of higher rank. As rank increases, the ring structures become more polycondensed and are joined by stronger cross-links. An examination of the yields of chloroform-soluble extracts, product distribution, and hydrogen utilization has implied that the generation of soluble materials can be characterized by two regimes of liquefaction. At low conversions, the products were of a high oil to asphaltene ratio which decreased and passed through a minimum upon extended reaction. Consideration of the hydrogen consumption in the region of minimum oil to asphaltene ratio has implied that the release of the mobile phase corresponded to a yield of about 15 to 20% for bituminous coals and 30 to 35% for subbituminous coals. The /sup 1/H NMR analysis of the chloroform-soluble extracts derived from the catalytic hydrogenation of a bituminous coal was found to change in a similar fashion as the product distribution. The soluble products at low and high conversion were more aliphatic in composition than the materials of intermediate conversion. 200 refs., 44 figs., 24 tabs. (ERA citation 14:005748)