EXTRACTION OF ARGONNE PREMIUM COAL SAMPLES WITH CS2-N-METHYL-2-PYRROLIDINONE MIXED-SOLVENT AT ROOM-TEMPERATURE AND ESR PARAMETERS OF THEIR EXTRACTS AND RESIDUES

The eight Argonne Premium Coal Samples were extracted at room temperature with CS2-N-methyl-2-pyrrolidinone (NMP) mixed solvent. Upper Freeport, Pittsburgh No. 8, Blind Canyon, Illinois No. 6, and Lewiston-Stockton coals gave high yields, i.e., 59.4, 39.0, 33.6, 33.1, and 27.1 wt % (daf), respectively. On the other hand, Pocahontas No. 3, Wyodak-Anderson, and Beulah-Zap coals gave only low yields, i.e., 2.8, 9.9, and 2.3 wt % (daf), rsepectively. The extracts obtained were fractionated with acetone and pyridine, respectively. For the extract from the Upper Freeport coal, a considerable amount of pyridine-insoluble fraction, i.e., a heavier extract fraction than preasphaltene, was obtained. ESR parameters of spin concentration, line width, and g value for the raw coals and their extracts and residues were determined. The spin concentration was the order of extract fractions < raw coal < residue for all coals used. The extract fractions also had larger line widths than those of the residues. © 1990, American Chemical Society. All rights reserved.