Computer-Aided Molecular Design Study of Coal Model Molecules. 3. Density Simulation for Model Structures of Bituminous Akabira Coal

The physical density of a macromolecular model (C₃₉₀H₃₆₂N₆O₃₈) for Japanese bituminous Akabira coal, which was previously constructed on the basis of the combined data of its Curie-point pyrolysis and CP/MAS ¹³C NMR, and of four kinds of the systematically modified models in the linkage fashion was estimated by the method using computer-aided molecular design (CAMD) software which we have previously proposed. The results suggest that (a) molecules consisting of a linear structure with branches are more suitable as the models, compared with those involving some cyclized parts due to the cross-linked bonds, and (b) medium-sized molecules yielded by fragmentation of the macromolecular model to some extent may be considered as the representatives for the solvent extractable parts in the coal.