以巴基斯坦俾路支褐煤(BL)为研究对象,由元素分析得出BL化学式为C167H130O53N2S。经X射线光电子能谱(XPS)分析BL有机结构中氧、氮和硫元素存在形式。利用傅里叶变换红外光谱(FT-IR)研究BL有机结构中主要官能团特征,—CH和—CH2为BL脂肪族结构中主要官能团。BL中苯环主要取代形式为三取代和四取代。运用核磁共振光谱(13C-NMR)探究BL有机结构碳骨架结构。BL分子结构中,芳香桥碳与周碳之比XBP为0.21,碳主要由芳香碳和脂肪碳2部分构成,其中脂肪碳质量分数53.23%,芳香碳占比41.93%。芳香结构以苯环和萘环为主,氧主要以羧基、羰基、醚氧和酚羟基形式存在,而氮主要以吡咯氮形式存在,硫主要为噻吩。建立BL二维分子结构模型,通过MaterialsStudio对其进行加氢饱和,构建BL分子模型三维立体结构,进一步优化所得分子模型,空间效果显著,得到能量最低的BL三维结构模型,发现范德华能是BL分子结构稳定的关键因素。通过计算得到的BL模型结构13CNMR谱图与试验所测谱图基本一致,验证了所构建BL结构模型的合理性。

Taking Balochistan lignite (BL) in Pakistan as the research object, the chemical formula of BL is C167H130O53N2S according toelement analysis. The existing forms of oxygen, nitrogen and sulfur in BL organic structure were analyzed by X-ray photoelectron spectroscopy (XPS). The characteristics of the main functional groups in the organic structure of BL were studied by Fourier transform infraredspectroscopy (FT-IR). The main functional groups in the aliphatic structure of BL are —CH and —CH2. The main substituted forms ofbenzene ring in BL are trisubstituted and tetra substituted. The carbon skeleton structure of BL organic structure was explored by13C-NMR. In the molecular structure of BL, the ratio of aromatic bridge carbon to pericarbon XBP is 0.21, and the carbon is mainly composed of aromatic carbon and fatty carbon, of which the mass fraction of fatty carbon is 53.23%, and the proportion of aromatic carbon is41.93%. The aromatic structure is mainly benzene ring and naphthalene ring, oxygen is mainly in the form of carboxyl, carbonyl, etheroxygen and phenolic hydroxyl, while nitrogen is mainly in the form of pyrrole nitrogen, and sulfur is mainly thiophene. A two-dimensional molecular structure model of BL was established. The three-dimensional structure of BL molecular model was constructed by hydrogenation saturation through materials studio, and the molecular model was further optimized. The space effect is significant, and the BL three-dimensional structure model with the lowest energy is obtained. It is found that van der Waals energy is the key factor for the stability ofBL molecular structure. The calculated 13C—NMR spectra of BL model structure are basically consistent with the experimental spectra,which verifies the rationality of the BL structure model.

0 引言

1 试验

   1.1 煤有机结构

   1.2 傅里叶红外光谱分析

   1.3 13C固体核磁共振波谱分析

   1.4 X射线光电子能谱分析

   1.5 分子模型构建步骤

2 结果与讨论

   2.1 主要化学官能团

   2.2 碳骨架结构分析

   2.3 氧、氮和硫的赋存形态

   2.4 分子模型的构建及优化

3 结论