Abstract:

Hongshiwan (HSW) coal from Ningdong China was characterized to determine key microstructural parameters of materials, such as elements, valence and chemical bonding, with proximate and ultimate analyses, solid state ¹³C nuclear magnetic resonance (¹³C NMR), X ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The results revealed that main structure of HSW coal was 75.96%(mass) aromatic skeleton and 0.315 ratio of aromatic bridge carbon to aromatic peripheral carbon, indicating more naphthalene than benzene and anthracene in coal. Oxygen predominantly presented in the form of ether (C-O), carbonyl (C=O) and carboxyl (-COO), which C-O was accounted for 53.57%. Nitrogen presented in the form of pyridine and pyrrole. Tri-and tetra-substituents were mainly located on benzene ring at 47.77% and 32.97%, respectively. Methyl (-CH₃) group was predominant in cyclic and aliphatic hydrocarbons. Thus, coal molecular formula was defined as C₂₂₁H₁₄₈O₂₈N₂ with molecular weight of 3142.32. Based on these results, macromolecular 2D and 3D model of HSW coal was built with computer-aided modelling. The model was optimized and further verified by FT-IR and ¹³C NMR spectra simulation by quantum chemical calculations. Therefore, molecular microstructures of HSW coal have been depicted from both experimental and quantum chemical approaches.

Key words: coal, model, computational chemistry, structural optimization, molecular simulation, spectral simulation

摘要：

使用工业分析、元素分析、固体核磁（¹³C NMR）、X射线光电子能谱（XPS）、傅里叶变换红外光谱（FT-IR）对宁东红石湾（HSW）煤样进行表征，获得煤样中元素赋存的种类、价态、化学键环境等物质微观结构的关键参数。结果表明HSW煤结构以芳香族为主，占75.96%，桥接芳碳与周碳比为0.315，可知其结构中以萘为主，苯和蒽为辅。氧原子主要以醚氧基（C—O）、羰基（C=O）和羧基（—COO）的形式存在，其中C—O占53.57%。氮原子以吡啶和吡咯的形式存在。苯环的连接方式以三、四取代为主，分别占47.77%、32.97%，脂肪族中环烷烃或脂肪烃—CH₃占优势。确定HSW煤的分子式为C₂₂₁H₁₄₈O₂₈N₂，分子量为3142.32。在此基础上结合计算机辅助实现了二维和三维大分子模型构筑。应用量子化学计算对HSW煤大分子模型进行了优化及核磁共振、红外光谱模拟，验证了所建模型的合理性。最终实现了HSW煤的微观分子结构的实验与量子化学描述。

关键词: 煤, 模型, 计算化学, 结构优化, 分子模拟, 光谱模拟