抚顺烟煤的固体核磁共振 X射线衍射和电子能谱的研究

STUDY ON FUSHUN BITUMINOUS COAL BY CP/MAS NMR X-RAY DIFFRACTION AND ESCA

用高分辨固体核磁共振,X射线衍射和光电子能谱等近代物理方法,研究了抚顺西露天矿长焰煤的镜煤质,以及该镜煤质的吡啶不溶物,吡啶可溶苯不溶物和超临界抽提后的残煤的大分子结构。获得了上述样品的芳香度参数(fa)、碳原子分布、微晶参数(dr,dm,da,dc)及碳、氧、氮元素的结合形态。并对抚顺西露天长焰煤的大分子结构提出了一些初步的看法。

It is well known that pyridine can extract light hydrogen-rich molecules trapped in hydrogen-poor macromolecular network with high yield of extract without destroying the basic skeleton of the coal structure.The molecular structure of pyridine extract is quile similar to the subunit structure of the macromolecular phase of the original coal. Therefore, it is reasonable to study the structural composition of the coal by studying its pyridine extract.The pyridine extract and the insoluble residue of the vitrinite of Fushun bituminous coal were characterized by different instruments.A schemalic macromolecular structure model is deduced that coal skeleton consists of an insoluble three dimensional network of large molecules-condensed aromalic sheets which are postulated to be stucked up one on top of another or to be cross-linked with each other parallelly, and with aliphatic chains or naphthenic rings protruding from the edges.The structural paramiters of the network,such as the average interlayer spacing (d_m), the average interchain spacing (d_r),the average stack height of aromatic clusters perpendicular to the plance of the sheets (L_c), the average effective number of aromatic sheets associated in a slack cluster (M), and the average layer diameter of the sheets (L_a), were obtained by x-ray diffraction analysis.The structural parameters of an aromatic sheet, i. e. the numbers of aromatic carbons, aliphatic carbons and carbonyl carbons were obtained by high field solid state ^(13)C-NMR analysis.X-ray photo-electron spectromelry studies revealed that organic oxygen is present in the coal in the form of carbonyl, hydroxyl, carboxyl and methoxy groups, of which, phenolic groups is the main form, while most of the nitrogen in the coal is incorporated in heterocyclic rings (such as pyridine and pyrroles) and amine groups.