Development of a Macromolecular Model for Yangdong Coal Via NMR, FTIR, and XPS Spectroscopy

Gang Zhang

doi:10.54691/9pdcjt06

Authors

Gang Zhang

DOI:

https://doi.org/10.54691/9pdcjt06

Keywords:

Molecular Structure Model, 13C NMR, XPS, FTIR.

Abstract

The molecular structure of coal is a critical factor determining its physicochemical properties and serves as a key bridge connecting macroscopic coal characteristics with microscopic molecular evolution. In this study, Yangdong coal (YD) was analyzed using a combination of techniques including proximate and ultimate analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and solid-state nuclear magnetic resonance (13C NMR) spectroscopy to systematically determine its elemental composition, surface functional groups, aromatic structure configuration, and aliphatic structure distribution of the coal sample. The results indicated that the YD coal had a bridge/peripheral carbon ratio of 0.20 and an aromaticity of 77.98%. The aromatic structures were predominantly composed of benzene, naphthalene, and phenanthrene, while the aliphatic carbon structures were mainly in cyclic form. Based on the analytical data, the molecular formula of the coal was determined as C₂₀₀H₁₄₇O₂₂N₃, with a molecular weight of 2944.38. The constructed macromolecular model showed that the aromatic structural units consisted of six benzene rings, five naphthalene rings, two phenanthrene (or anthracene) rings, and one pyrene ring. Nitrogen atoms were present in the forms of pyridine and pyrrole. Using these findings, a molecular structure model was constructed and optimized through simulation, providing key insights into the molecular structure of coal and offering important guidance for its efficient utilization.

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