EVALUATION OF ASSOCIATION OF SOLVENT-SOLUBLE MOLECULES OF BITUMINOUS COAL BY COMPUTER-SIMULATION

Solvent-soluble constituents were obtained from the extraction with carbon disulfide-N-methyl-2-pyrrolidinone (CS2-NMP) mixed solvent at room temperature. The energy-minimum conformations of these extract constituents, which were obtained by computer-aided molecular design (CAMD) of the molecular mechanics and the molecular dynamics methods using the structural models constructed based on their structural parameters, showed that associated structures of coal molecules through noncovalent interactions are the most stable conformation. It also showed that the van der Waals and electrostatic interactions made a larger contribution to the stabilization of the associated structures than the hydrogen-bonding interaction, since the number of hydrogen bondings is few; compared to those for other nonbonded interactions.