A COMPUTER-AIDED MOLECULAR-MODEL FOR HIGH VOLATILE BITUMINOUS COAL

This study defines a three dimensional chemical representation of a coal macromolecule based on data from physiochemical analyses. Both atomic and molecular information is introduced in the computerized model (SIGNATURE Program). The atomic information includes elemental analysis and C-13 NMR data. The molecular information involves analyses of the pyrolysis products of the macromolecule. The components analyzed are molecular fragments of the coal and their structures are determined by gas chromatography/mass spectrometry. The main task of the program is to assemble these fragments to obtain a molecule which is consistent with the atomic information. The computerized method, based on a combinatorial program is able to compute one, several or all non-isomorphic models which can be built. An example of such an approach is presented for vitrinite from high volatile bituminous coal. The SIGNATURE program was used to construct one of the many possible structural isomers in three dimensions. An energy minimization program was subsequently applied to identify the structure as it might exist in it lowest energy conformation. The resulting model forms a reasonable representation in terms of energy, density, and number of cross-links.