The investigation of chemical structure of coal macerals via transmitted-light FT-IR microspectroscopy.
The investigation of chemical structure of coal macerals via transmitted-light FT-IR microspectroscopy.
复制标题
DOI：
10.1016/j.saa.2005.01.020
复制
发表时间：
2005-11
期刊：
影响因子：
--
通讯作者：
S. Xuguang
中科院分区：
文献类型：
--
作者：
S. Xuguang
中国南方晚二叠世煤以其特有的显微组分“树皮体”和元素氢含量高为特征，焦油产率高，具有显著的产油潜力。“树皮体”一直被认为是木栓质体，但现在许多中国工作者认为“树皮体”不是木栓质体，而是一种独特的显微组分。“树皮石”一词曾于1991年、1995年和1999年被中国国家技术监督局正式认证和命名，但尚未被国际煤炭地质学家和ICCP认可为科学术语。利用透射显微红外光谱和曲线拟合分析研究了“树皮体”的化学结构，同时对镜质体、丝质体和孢子体进行了平行研究。与其他类型的显微组分相比，“barkinite”的显微FT-IR光谱的特征在于在3000- 2800 cm − 1处的脂肪族CHx伸缩振动和1460- 1450 cm −1处的变形非常强，在1610- 1600 cm − 1处的芳香族CC环伸缩振动和900- 700 cm −1处的芳香族CH面外变形的强度较低。“树皮石”分子结构中的脂肪族侧链较长且分支较少。此外，在1100- 1000 cm −1处还出现了强烈的脂肪醚COC和醇CO伸缩振动，在3050- 3030 cm −1处出现了显著的芳香CH伸缩振动，在3600- 3200 cm − 1范围内出现了弱的水OH伸缩振动，在1740- 1700 cm −1处出现了稀酸CO基团吸收。红外光谱特征表明，“树皮体”由大量的长链烷烃、少量的芳烃和少量的芳烃组成。“树皮体”的化学结构表明，中国南方晚二叠世煤的高焦油产率和较高的产油潜力是由于乐平煤中“树皮体”含量高和显微组分中含有大量的长链脂肪族物质所致。
The Late Permian coals from South China are characterized by high content of the unique maceral “barkinite” and elemental hydrogen, typically produce high yields of tar, and exhibit significant oil-producing potential. “Barkinite” has been identified as suberinite for a long time, but now many Chinese workers have concluded that “barkinite” is not suberinite, rather it is a distinct maceral. The term “barkinite” was formally certified and named by the State Bureau of Technical Supervision of PR China in 1991, 1995, and 1999, however, it has not been recognized as a scientific term by international coal geologists and the ICCP. Transmitted-light FT-IR microspectroscopy and curve-fitting analysis were used to investigate the chemical structure of “barkinite”; at the same time, parallel studies were also carried out on vitrinite, fusinite, and sporinite. In comparison with other maceral types, the micro-FT-IR spectra of “barkinite” are characterized by very strong intensities of aliphatic CHxstretching vibrations at 3000–2800cm−1and deformations at 1460–1450cm−1, less intense bands from aromatic CC ring stretching at 1610–1600cm−1and aromatic CH out-of-plane deformations at 900–700cm−1. The aliphatic side-chains in the molecular structure of “barkinite” are longer and less branched. In addition, there also appear intense aliphatic ether COC and alcohol CO stretching bands at 1100–1000cm−1, notable aromatic CH stretching vibrations at 3050–3030cm−1, weak OH stretching bands of water in the 3600–3200cm−1range, and rare acid CO group absorption at 1740–1700cm−1. Collectively the IR spectral characteristics indicate that “barkinite” is composed of great numbers of long chain aliphatics, a fewer of aromatics and rare of oxygenate components. The chemical structure of “barkinite” show that the high tar yields and the relatively high oil-producing potential of the Late Permian coals from South China are attributable to the high “barkinite” content in the Leping coals and the great numbers of long chain aliphatic substances contained in this maceral.