Structural aspects of sub-bituminous coal deduced from solvation studies. 2. Hydrophenanthrene solvents
✍ Scribed by Raffaele G. Ruberto; Donald C. Cronauer; Douglas M. Jewell; Kalkunte S. Seshadri
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- English
- Weight
- 893 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0016-2361
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✦ Synopsis
In order better to delineate the contribution of coal molecules to liquefaction products, donor solvents of discrete structure and narrow molecular-weight range have been satisfactorily employed. Partially hydrogenated phenanthrenes are ideally suited for these studies. This ring system is (a) prevalent in all coals, (b) thermally stable, and (c) capable of functioning ideally in a redox environment. Coal depolymerization can take place in the absence of a catalyst and hydrogen, provided that the level of hydroaromatics, especially octahydrophenanthrene, is sufficiently high to ensure that the coal free-radicals can be quenched before they recombine. Solvation (liquefaction) levels reach a maximum (>98%) with octahydrophenanthrene, making the indirect study of coal possible with a minimum of solvent 'background'. The role of catalyst, if used during solvation, appears to be that of maintaining the proper level of hydroaromatics and of upgrading the liquids produced. Sub-bituminous coal appears primarily to consist of two-and three-condensedring structures linked by heteroatoms, mainly oxygen.