Macromolecular structural model of the pyridine extracted residue of vitrain from No.3 coalbed, Liulin and molecular simulation
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摘要: 对柳林3#镜煤吡啶抽提残煤(LLR)进行了13C CP/MAS NMR和XPS分析,结合元素分析和工业分析,构建了其大分子模型。LLR结构中芳香部分以蒽为主,脂肪结构主要以脂肪侧链的形式存在,氧原子分别以醚键、羟基和羰基形式存在,氮原子以吡咯和吡啶的形式存在。运用13C NMR预测软件ACD/CNMR predictor计算了大分子结构模型的13C化学位移。与实验13C NMR谱图相比较,对LLR的大分子结构模型进行了修正,获得了13C NMR计算谱能和实验谱图吻合较好的大分子结构模型。采用分子模拟对LLR化学结构模型进行能量优化,结果表明,大分子结构的能量按其大小排序主要为范德华能、键扭转能、键角能与键伸缩能。芳环之间的平行排列在该结构模型中占有很小的比例。最后通过添加周期性边界条件得到该煤的密度为1.22 g/cm3。量子化学半经验方法(PM 3)模拟结构表明,脂肪侧链中的C-C键较长,因而活性较高;边缘碳原子带有较多的负电荷,易于发生氧化反应;芳香碳原子所带电荷较少,稳定性很高。Abstract: The pyridine extraction residue from LL 3#vitrain (LLR) was studied by 13C CP/MAS NMR and XPS analysis. 13C NMR tests show the structure characteristics of carbon atom and 12 structure parameters. Aromatic structure units are dominated by anthracene; aliphatic C atoms exist in the side-chain; O atoms exist in the form of -O-, C=O and -OH; N atoms exist in pyridine and pyrrole. Macromolecular structure model of LLR is constructed based on the results of proximate and ultimate analysis. 13C chemical shift of LLR macromolecular structure is calculated by ACD/CNMR predictor, then the structure is corrected according to the calculation results. And finally the macromolecular structure which is consistent with the experimental results is obtained. Molecular mechanics (MM) and molecular dynamics (MD) were adopted to simulate the energy-minimum conformation of LLR model. The results show that the order of main energy for LLR model is van der waals>torsion>angle>bond. The simulation results indicate that the parallel aromatic layer structure occupies a small proportion. Finally, LLR density is 1.22 g/cm3 by enclosing coal model into the periodical boundary condition. Semi-empirical quantum chemistry methods (PM3) simulation indicates that the C-C bonds adjacent to aliphatic side chain C atoms exhibit higher activity. The terminal C atoms are more negatively charged, and therefore prone to undergo oxidation reactions. The aromatic C atoms are characterized by fewer charges and very high stability.
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虞继舜. 煤化学 [M]. 北京: 冶金工业出版社, 2000. (YU Ji-shun. Coal chemistry [M]. Beijing: Metallurgical Industry Press, 2000.) GREEN T, KOVAC J, BRENNER D, LARSEN W. Coal structure[M]. New York: Academic Press, 1982. IINO M. Network structure of coals and association behavior of coal-derived materials[J]. Fuel Process Technol, 2000, 62(2/3): 89-101. 谢克昌. 煤的结构与反应性[M]. 北京: 科学出版社, 2002. (XIE Ke-chang. Coal structure and its reactivity[M]. Beijing: Science Press, 2002.) MATHEWS J P, HATCHER P G, SCARONI A W. Proposed model structure for Upper Freeport and Lewison-Stockon vitrinites[J]. Energy Fuels, 2001, 15(4): 863-873. MEYERS R A. Coal structure[M]. New York: Academic Press, 1982. TAKANOHASHI T, KAWASHMA H. Construction of a model structure for Upper Freeport coal using 13C NMR chemical shift calculations[J]. Energy Fuels, 2002, 16(2): 379-387. OHKAWA T, SASAI T, KOMODA N, MURATA S, NOMURA M. Computer-aided construction of coal molecular structure using construction know ledge and partial structure evaluation[J]. Energy Fuels, 1997, 11(5): 937-944. 王三跃, 曾凡桂, 田承圣, 张通. 分子模拟在煤大分子结构演化研究中的应用及进展[J]. 太原理工大学学报, 2004, 35(5): 541-544. (WANG San-yue, ZENG Fan-gui, TIAN Cheng-sheng. Application of advance of molecular simulation in the study of evolution of coal macromolecular structure[J]. Journal of Taiyuan University of Technology, 2004, 35(5): 541-544.) GIVEN P H, MARZEC A, BARTON W A. The concept of a mobile or molecular phase within the macromolecular network of coals: A debate [J]. Fuel, 1986, 65(2): 155-163. 徐秀峰, 张蓬洲. 高分辨固体13C-NMR和XPS技术表征碳的骨架结构[J]. 煤炭转化, 1995, 18(4): 57-62. (XU Xiu-feng, ZHANG Peng-zhou. The study of carbon structure by solid13C-NMR and XPS[J]. Coal Conversion, 1995, 18(4): 57-62.) 叶超辉, 李新安. 煤的固体高分辨13C-NMR谱[J]. 科学通报, 1985, 30(20): 1545-1547. (YE Chao-hui, LI Xin-an. High resolution of solid state 13C-NMR spectrum in coal[J]. Chinese Sci Bull, 1985, 30(20): 1545-1547.) 谷小会, 周铭, 史士东. 神华煤直接液化残渣中重质油组分的分子结构[J]. 煤炭学报, 2006, 31(2): 76-80. (GU Xiao-hui, ZHOU Ming, SHI Shi-dong. The molecular structure of heavy oil fraction from the Shenhua coal direct liquefaction residue [J]. Journal of China Coal Society, 2006, 31(2): 76-80.) 姚明宇, 刘艳华, 车得福. 宜宾煤中氮的形态及其变迁规律研究[J]. 西安交通大学学报, 2003, 37(7): 759-763. (YAO Ming-yu, LIU Yan-hua, CHE De-fu. Investigation of nitrogen functionality in Yibin coal and its char[J]. Journal of Xian Jiaotong University, 2003, 37(7): 759-763.) 常海洲, 王传格, 曾凡桂, 李军, 李文英, 谢克昌. 不同还原程度煤显微组分组表面结构XPS对比分析[J]. 燃料化学学报, 2006, 34(4): 389-394. (CHANG Hai-zhou, WANG Chuan-ge, ZENG Fan-gui, LI Jun, LI Wen-ying, XIE Ke-chang. XPS comparative analysis of coal macerals with different reducibility [J]. Journal of Fuel Chemistry and Technology, 2006, 34(4): 389-394.) 王丽, 张蓬洲, 郑敏. 用固体核磁共振和电子能谱研究我国高硫煤的结构 [J]. 燃料化学学报, 1996, 24(6): 539-543. (WANG Li, ZHANG Peng-zhou, ZHENG Min. Study on structural characterization of three Chinese coals of high organic sulphur content using XPS and solid-state NMR spectroscopy [J]. Journal of Fuel Chemistry and Technology, 1996, 24(6): 539-543.) 傅家漠, 刘德汉, 盛国英. 煤成烃地球化学[M]. 北京: 科学出版社, 1990. (FU Jia-mo, LIU De-hua, SHENG Guo-ying. Geochemistry of coal-formed hydrocarbon[M]. Beijing: Science Press, 1990.) 贾建波. 神东煤镜质组结构模型的构建及其热解甲烷生成机理的分子模拟. 太原: 太原理工大学, 2010. (JIA Jian-bo. Construction of structural model and molecular simulation of methane formation mechanism during coal pyrolysis for shendong vitrinite. Taiyuan: Taiyuan University of Technology, 2010.) 李军, 冯杰, 李文英, 常海洲, 谢克昌. 强弱还原煤聚集态对其可溶性影响的分子力学和分子动力学分析[J]. 物理化学学报, 2008, 24(12): 2297-2303. (LI Jun, FENG Jie, LI Wen-ying, CHANG Hai-zhou, XIE Ke-chang. Determining influence of the aggregative state of deoxidized coal on its extraction by molecular mechanics and molecular dynamics analysis[J]. Acta Phys. Chim. Sin., 2008, 24(12): 2297-2303.) TAKANOHASHI T, NAKAMURA K, IINO M. Computer smulation of methanol swelling of coal molecules[J]. Energy Fuels, 1999, 13(4): 922-926. TAKANOHASHI T, NAKAMURA K, IINO M. Computer simulation of solvent swelling of coal molecules: Effect of different solvents[J]. Energy Fuels, 2000, 14(2): 393-399. Li Z, WARD C R, GURBA LW. Occurrence of non-mineral inorganic elements in macerals of low-rank coals[J]. In t J Coal Geology, 2010, 81(4): 242-250. 曾凡桂,张通,王三跃,谢克昌. 煤的超分子结构的概念及其研究途径与方法[J]. 煤炭学报, 2005, 30(1): 85-89. (ZENG Fan-gui, ZHANG Tong, WANG San-yue, XIE Ke-chang. Concept of supramolecular structure of coal and its research approach, methodology[J]. Journal of China Coal Society, 2005, 30(1): 85-89.)
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