Energy & Fuels, Vol.12, No.4, 697-703, 1998
X-ray analysis of liquid-treated coals. 1. Effects of pyridine on the short-range structuring in Beulah Zap lignite
The X-ray scattering curves are statistically indistinguishable, except for a small difference at very low angle, for a sample of "as received" Beulah Zap lignite and for the Beulah Zap which has been dried at 107 degrees C in a convection oven. The addition of pyridine to Beulah Zap causes a significant change in the X-ray scattering curves obtained in the 1.0-2.5 Angstrom(-1) region of reciprocal space, and this difference is also found in the resulting structure curves which have been calculated in molecular (real) space. A model that suggests pyridine is hydrogen bonded to the oxygens contained in attachments which are covalently bonded to the "planar" C-9 units of Beulah Zap has been suggested, and both the specific and the average atom-pair distances calculated from this model are consistent with the structure function calculated from the X-ray scattering curve of the BZ-PYR sample.
Keywords:ARGONNE PREMIUM COALS;BITUMINOUS COAL;MACROMOLECULAR NETWORK;COMPUTER-SIMULATION;SOLUBILITY;STATE;NMR;SPECTROSCOPY;ASSOCIATION;EXTRACTS