Construction of macromolecular structural model of anthracite from Chengzhuang coal mine and its molecular simulation

The macromolecular structure model of Chengzhuang coal was constructed based on the results of proximate and ultimate analysis, ¹³C-NMR spectrum and XPS spectrum. In the model the numbers of rings in polycyclic aromatic hydrocarbon were distributed between 1 and 5. The aliphatic C atoms existed in the forms of -CH₃,-CH₂- and cycloalkanes. 9 atoms of O were in the form of C=O, while one in the form of -OH and another one in the form of -O-. 2 atoms of N were in pyrrole, while S atom did not appear in the model because its concentration was lower than 1%. Molecular mechanics (MM) and molecular dynamics (MD) was adopted to simulate the energy-minimum conformation of the model and the results showed that the aromatic layers tended to be parallel by intramolecular or intermolecular π-π interaction and the latter should be one of the main contributors for the short-range ordering of high-rank coal structure. The van der waals energy and hydrogen bond energy contributed to the energy-minimum conformation.