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U.S. Department of Energy
Office of Scientific and Technical Information

Guest molecules in coal: Final technical report

Technical Report ·
OSTI ID:6888593

Potassium-crown ether was used to gently snip at the ether, alkyl and hydrogen bond crosslinks resulting in dismantling the coal macromolecular structure at room temperature and atmospheric pressure. This permitted easy extraction of low molecular weight compounds, the so-called guest molecules, which are only partially extractable by solvent extraction procedures and permit detailed characterization studies to be performed on them. This reaction also resulted in obtaining soluble chunks of coal oligomer fragments that would be more amenable to detailed chemical and spectroscopic analysis without recourse to any heat or pressure. After three and four consecutive K-CE treatments, 51 and 78% of the coal was solubilized into two different THF fractions and an alkali fraction. FT-IR studies suggests that the K-CE reaction is releasing the same type of coal fragments after each successive K-CE reaction---kind of peeling of successive macromolecular layers composed of the same or very similar structural units. Further, the K-CE reagent is reducing phenolics groups in coal to carbonyls and ethylene/methylene linkages are not deemed predominant in this coal. /sup 1/H, /sub 13/C NMR and tandem mass spectrometry (ms/ms) identified a homologous series of alkylnaphthalenes, alkyldihydronaphthalenes, and alkyltetralins with the polymethylene chain extending up to 14 carbons in the THF-1 fraction. It was established that the polymethylene chains are present as an integral part of the coal macromolecular matrix and as trapped molecules (guest molecules) in the coal. 21 refs., 35 figs., 13 tabs.

Research Organization:
Purdue Univ., Lafayette, IN (USA)
DOE Contract Number:
FG22-84PC70792
OSTI ID:
6888593
Report Number(s):
DOE/PC/70792-T7; ON: DE88005808
Country of Publication:
United States
Language:
English