Abstract:

The structural composition of different asphaltenes，which were separated by n⁃heptane fromVenezuelan atmospheric residue (WNAR), Liaohe vacuum residue (LHVR), Tahe atmospheric residue (THAR), Iranian vacuum residue (YLVR), and Chunliang vacuum residue (CLVR), was investigated by FT⁃IR and XPS. FT⁃IR results show that the substituents on benzene rings of asphaltenes are diverse, dominated by meta⁃disubstituted or trisubstituted benzene rings, while monosubstituted benzene rings are barely detected. Hydroxyl and sulfoxide groups existed in different asphaltenes. Oxygen⁃containing functional groups were dominated by aromatic ethers, and the aliphatic C-H structure was dominated by -CH₂ groups. XPS results indicate that surface carbon species of asphaltenes are primarily aromatic carbon with few carbon oxygen bonds, which are mostly C—O, whereas C=O and —COOH account for a very low proportion. Surface nitrogen species are mainly pyridinic nitrogen and pyrrolic nitrogen, with a small fraction of quaternary nitrogen. Surface sulfur species consist mainly of thiophenic sulfur and aliphatic sulfur. Good consistency is achieved between the two characterization results, which further verifies the accuracy of the understanding of asphaltene structural composition.

Key words: Asphaltene, Substituent, Functional groups, Heteroatom

摘要：

以委内瑞拉常压渣油、辽河减压渣油、塔河常压渣油、伊朗减压渣油和纯梁减压渣油为原料，利用FT⁃IR和XPS考察了几种渣油沥青质的结构组成。FT⁃IR结果表明，沥青质苯环上的取代基较为多样，且以间二取代苯环或三取代苯环为主，几乎不存在单取代苯环；不同渣油沥青质中均存在羟基和亚砜基，含氧官能团以芳香醚为主，脂肪族C-H结构以-CH2基团为主。XPS结果表明，沥青质表面碳元素以芳香碳为主，碳氧键较少且以C—O为主，而C=O和—COOH占比很少；表面氮元素以吡啶氮和吡咯氮为主，季氮占比较少；表面硫元素以噻吩硫和脂肪硫为主。两种分析结果具有较好的一致性，进一步验证了对沥青质结构组成认识的准确性。

关键词: 沥青质, 取代基, 官能团, 杂原子