Abstract:

Dagang vacuum residue (VR) and its supercritical fluid extraction and fractionation (SFEF) tailing were separated into four group compositions (SARA) by chromatographyThe molecular structural features of the asphaltenes from VR and SFEF tailing were investigated with ruthenium ion catalyzed oxidation (RICO)By means of GCMS and GC analysis, the homologous series of n-alkanoic acids (C₄—C₃₃) and α,ω-di-n-alkanoic acids (C₄—C_24) were detected and measured quantitativelyThe distribution of these carboxylic acids obtained from the oxidation reaction was useful in determining the distribution of polymethylene bridge bonds and alkyl side chainsThe results indicated that the molar concentrations of n-alkyl side chains and polymethylene bridges decreased with the increase of chain length, and were characterized by eventoodd carbon number preferenceSFEF tailing asphaltene had less C₂₅₊ but more C₁₇—C₂₅ n-alkyl side chain than VR asphalteneFurthermore, the polymethylene bridge concentration of VR asphaltene was about 25 folds of SFEF tailing asphalteneThe above information demonstrated that cracking reaction might occur in the SFEF process.

Key words: 减压渣油, 超临界萃取残渣, 钌离子催化氧化, 烷基侧链, 聚亚甲基桥接链

摘要：

利用钌离子催化氧化（RICO）方法研究了大港减渣庚烷沥青质和大港减渣超临界萃取（SFEF）残渣庚烷沥青质的化学组成和结构特征。结果表明，两种庚烷沥青质的芳香结构上都存在一定量的烷基侧链和桥接不同芳碳的聚亚甲基桥接链，烷基侧链碳数最大约为33，聚亚甲基桥最大碳数约为24，含量均随碳数的增加呈递减趋势，并存在不同程度的偶碳优势。SFEF残渣沥青质C_25＋烷基侧链比减渣沥青质少，但C₁₆～C₂₅的烷基侧链比减渣沥青质多，SFEF残渣沥青质的聚亚甲基桥接链含量比减渣沥青质少约25倍，这说明减渣沥青质中部分长链结构在SFEF过程中可能发生了热裂化反应。

关键词: 减压渣油, 超临界萃取残渣, 钌离子催化氧化, 烷基侧链, 聚亚甲基桥接链