Control of the chemical structure of perhydrous coals; FTIR and Py-GC/MS investigation
Control of the chemical structure of perhydrous coals; FTIR and Py-GC/MS investigation
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DOI：
10.1016/s0165-2370(00)00209-6
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发表时间：
2002-01-01
影响因子：
6
通讯作者：
Suárez-Ruiz, I
中科院分区：
文献类型：
--
作者：
Iglesias, MJ;del Río, JC;Suárez-Ruiz, I
为了从分子水平上确定氢含量与煤结构修饰之间的相互关系，本文对一组过水煤（主要由腐殖岩/镜质组显微组分组成）进行了分析。该研究包括对煤的直接固态表征，并结合对通过闪蒸热解获得的煤网的代表性碎片的分析。煤的过水特性既没有反映在脂肪氢浓度（从红外光谱数据）上，也没有反映在热解产物中直链脂肪基团的存在上。结构研究表明，过水煤主要含有1-2环的芳香结构，大尺寸芳香环的浓度非常小。与此一致的是，苯酚和烷基酚是最主要的降解产物，而芳香化合物（主要是苯和萘衍生物）是次要的，可能是蒸发性的化合物。所研究样品中的主要结构元素是简单的酚类，具有取代对烷基的优势。结果表明，氢富集过程影响了芳烃化反应和缩合反应。在过水煤的自然演化过程中，木质素前体中氧合官能团的转化似乎没有发生木质素框架的平行结构重组，而木质素框架负责形成多环芳烃体系。结果表明，煤中过水镜质组的化学结构与“正常”煤中的化学结构相比发生了很大的变化。结果还表明，氢含量的来源及其在煤的后续演化过程中的作用影响了过水镜质组的化学结构，从而影响了其性质和行为。(C) 2002 Elsevier Science B.V.版权所有
This work analyses a set of perhydrous coals (mainly composed of huminite/vitrinite maceral group) in order to determine the inter-relations between the hydrogen content and the modifications in the coal structure at a molecular level. The study involves the direct solid state characterisation of the coal combined with the analysis of representative fragments of the coal network obtained through flash-pyrolysis. The perhydrous character of the coals is not reflected either in the aliphatic hydrogen concentration (from FTIR data) or by the presence of straight-chain aliphatic moieties in the pyrolysates. This structural study shows that perhydrous coals contain mainly aromatic structures with 1-2 rings and a very small concentration of aromatic rings of large size. In agreement with this, phenol and alkyl phenols are the most prominent degradation products whereas bother aromatic compounds (mainly benzene and naphthalene derivatives) are minor and probably evaporative compounds. The major structural elements in the samples studied are simple,phenols with a preponderance of substituted para alkyl. The results obtained show that the processes of hydrogen enrichment affect the reactions of aromatisation and condensation. During the natural evolution of the perhydrous coals the transformations of the oxygenated functionalities in the lignin precursor seem to have taken place without the parallel structural reorganisation of the lignin framework responsible for the formation of polycyclic aromatic systems. As a result, the chemical structure of perhydrous vitrinites in coals is substantially modified with respect to that described in 'normal' coals, The results obtained also indicate that the source of hydrogen content and the effect that it has during the subsequent evolution process of the coals, affects the chemical structure of the perhydrous vitrinite and hence its properties and behaviour. (C) 2002 Elsevier Science B.V. All rights reserved.