基于固体^(13)C核磁共振技术对油砂沥青质结构的研究

Study on structural features of oil sands with solid state ^(13)C NMR

采用固体13C核磁共振(13C NMR)技术对油砂沥青质的化学结构特征进行详细的研究。通过对油砂沥青质的核磁谱图分析,获得了表征油砂沥青质结构特征的12个碳结构骨架参数。根据研究分析结果,油砂沥青质中的脂碳含量达60%左右,表明其化学结构主要以脂碳结构为主。在脂碳中,亚甲基含量最多,主要出现在脂肪链中,且其脂肪链平均长度小于8个碳原子,可推断为中等长度脂链;芳香碳含量小于40%,其中质子化芳香碳含量多于非质子化芳香碳。在非质子化芳香碳中芳香桥碳含量最多,可推断芳香碳呈多环模式;羰基碳在油砂沥青质结构中所占比例极小。虽然基于获得的油砂沥青质的元素组成,可以将油砂沥青质归类到Ⅰ型干酪根,但是两者在成烃潜量和结构特征都存在较大差异,由此判断油砂沥青质并非干酪根的降解产物。

Chemical structure of bitumen from oil sand was studied with 13C NMR. Through the analysis of the NMR spectra, 12 carbon skeleton parameters characterizing oil sand bitumen structure were obtained. As the result of the analysis,content of lipid carbon in oil sand bitumen was around 60%,showing predominant lipid carbon structure. The major component of aliphatic carbon,methylene carbon was mostly in the aliphatic chain. The average length of aliphatic chains was less than 8 carbon atoms,which belonged to medium length. Aromatic carbon content was less than 40%,and protonated aromatic carbons were greater than non-protonated aromatic carbons. Bridghead aromatic carbon was the most in the non-protonated aromatic carbons,inferring aromatic carbon in the polycyclic mode. Carbonyl carbon in oil sand bitumen accounted for only an extremely small amount. Although according to elemental composition,oil sand bitumen could be classified as Type Ⅰ kerogen,but there was difference in hydrocarbon generation potential and structure characteristics. The oil sand bitumen was not the degradation product of kerogen.