吡啶抽提前后柳林3~#煤的FTIR结构特征分析

FTIR Structure Characterization Analysis of Liulin 3~# Coal Before and After Pyridine Extraction

为了解处于第二次煤化跃变过程中的柳林3~#煤的大分子结构特征,采用溶剂吡啶对柳林3~#原煤进行索氏抽提,借助FTIR分析测试手段并通过分段分峰拟合对柳林3~#原煤、抽提后残煤及抽提物的结构组成及其变化进行了研究。结果表明:抽提过程中,在吡啶溶剂的作用下,部分抽提物从煤大分子结构中脱离出来,这些抽提物包括短链脂肪结构和芳香醚、酚、酯等含氧官能团结构。抽提前后煤大分子骨架保持相对稳定,与原煤和抽提后残煤相比,抽提物的苯环四取代明显增加,二取代明显减少,说明残煤的脂肪链长、支链少,抽提物的脂肪链短、支链多。抽提后残煤、抽提物与原煤显示出不同的芳香度,其由大到小依次为抽提后残煤的芳香度、原煤的芳香度、抽提物的芳香度;柳林3~#原煤、抽提后残煤及抽提物中主要羟基类型是自缔合羟基,说明煤中羟基类型以缔合结构为主。

In order to understand the macromolecular structure characteristics of Liulin3~#coal during the second coalification jump process,Liulin 3~#raw coal was extracted by pyridine.By means of FTIR,the raw coal,residues and extracts were studied with curve-fitting analysis to obtain the strcture and its change information.The results show that under the action of pyridine solvent,some extracts are separated from the macromolecular structures.These extracts include short chain aliphatic structure,aromatic ether,phenol and other oxygen-containing functional groups.The skeleton of coal macromolecule remains relatively stable before and after extraction.Compared with the raw coal and the residual coal,the benzene ring tetrasubstitution of the extract increases obviously,while the disubstitution decreases obviously.The results show that the residuals have a longer aliphatic chain and fewer branched chains,and the extracts have short fat chains and many branched chains.Different aromaticity is shown in residues,extracts and raw coal,and the aromaticity order is residues,raw coal,extracts from large to small.The main hydroxyl groups in Liulin 3~#coal,residues and extracts are self-associating hydroxyl groups,which indicates that the main hydroxyl groups in coal are associative structures.