Abstract: Five different oil shale kerogens were analyzed with advanced testing techniques (XRD, ¹³C NMR and FT-IR) to obtain important structural information. The long-range disordered state of aggregation was also confirmed by XRD. Using ¹³C NMR spectroscopy, 18 characteristic parameters of carbon skeleton structure were obtained. Detailed information about the chemical structure of kerogen was obtained through verifying the results of ¹³C NMR experiments with the qualitative analysis of kerogen groups made by FT-IR technique. The aliphatic structure of oil shale kerogen was up to 60%—90%, with the methylene carbon occupying the dominant position of 77%—90%, and most of the aliphatic structure were straight-chain while less alicyclic or branched chain. In addition to Huadian oil shale with a monocyclic aromatic carbon structure, the other four oil shale kerogens were co-existing monocyclic and polycyclic rings, with the latter mainly peri-condensed. The oxygen structure was C-O (alcohol, phenol, ether) and C=O, and carboxyl class was more than carbonyl class C=O. More C=O in kerogen was due to a low degree of metamorphism, while a high degree of metamorphism resulted in more C-O.

Key words: oil shale kerogen, solid state ¹³C NMR, FT-IR spectroscopy, chemical structure

摘要： 利用先进的测试技术对5种不同地区的油页岩干酪根分别进行XRD、¹³C NMR与FT-IR分析,获得重要结构信息。通过XRD检测分析,确定5种干酪根以长程无序的聚合状态存在。采用¹³C NMR技术表征出干酪根的碳原子化学结构,并获得碳骨架结构的18个重要参数。最后利用FT-IR技术对干酪根官能团进行定性分析,与 ¹³C NMR实验结果互相验证,得到干酪根化学结构的详细信息。结果表明:油页岩干酪根脂碳结构最多,高达60%～90%。其中又以亚甲基碳为主,有77%～90%,且多数为直链结构,脂环或支链结构较少。芳碳结构除桦甸以单环为主外,其余均为单环和多环结构并存,其中多环结构以迫位缩合为主。氧结构总体以碳氧单键(醇、酚或醚基)和C=O两种形式存在,其中羧基类C=O多于羰基类C=O。变质程度低的干酪根中存在较多C=O,而高变质程度的干酪根则以碳氧单键C-O为主。

关键词: 干酪根, 固体核磁, 红外光谱, 化学结构