晋城无烟煤的分子结构特征分析

Molecular structure analysis of Jincheng anthracite coal

利用工业分析、元素分析、核磁共振碳谱(^(13)C-NMR)、高分辨率的透射电镜(HRTEM)、红外光谱(FTIR)和X射线光电子能谱(XPS)对晋城无烟煤进行了分析,对其化学结构获得了较为全面的认识。采用变接触时间和偶极去相方法相结合的^(13)C-NMR技术以及HRTEM检测对其微晶条纹芳核结构进行了统计分类。结果表明:此类煤结构中桥碳比为0.46,平均结构单元分子质量为398,煤中的芳核结构缩合程度较高,芳香层片以苯并蒽,苯并芘以及尺寸更大的芳香环为主。对FTIR与XPS检测结果进行分峰拟合结果表明:芳香环取代度较高。煤中氮含量较少,以有机氮和无机氮的形式存在。煤样中硫主要以有机硫的形式存在,无机硫含量较少。煤中氧含量很少,且主要分布于脂肪烃结构中。煤样脂肪结构中侧链短,且分支度小。利用上述信息,初步构建了晋城无烟煤平均结构单元分子模型,其平均结构单元分子式为C_(30)H_(22)O_(0.5)N_(0.5),为煤的大尺度分子聚集体结构模型构建提供基础。

To have a more comprehensive understanding on the chemical structure,Jincheng anthracite are analyzed by using industrial analysis,elemental analysis,^（13）C nuclear magnetic resonance（^（13）C-NMR）,high resolution transmission electron microscopy（ HRTEM）,Fourier transform infrared spectroscopy（ FTIR） and X-ray photoelectron spectroscopy（ XPS）. The results show that the coal structure bridge carbon ratio is 0. 46,the average structural unit molecular mass is 398. In addition,the condensation degree of aromatic nuclei in coal structure is high because most of aromatic layers are in the forms of benzo anthracene,benzo pyrene as well as larger aromatic ring. High degree of aromatic ring substitution was found from FTIR and XPS analysis. A small amount of nitrogen,in the forms of organic and inorganic nitrogen,is present in coal. Sulfur mainly exists in the form of organic sulfur and inorganic sulfur. However,the content of inorganic sulfur in coal sample is much less than organic sulfur. The content of oxygen element is low in coal and most of oxygen species are attributed to the pedant groups in aliphatic side chain which is short with a low branching degree. Based on the above information,an average structural unit molecular model of Jincheng anthracite was prelimina-rily constructed,and its average structural unit molecular formula is C（30）H（15. 5）O（0. 5）N（0. 5）,which will provide a fundamental building block for the large scale molecular assembly model.