NMR波谱解析渣油组分的化学结构

Analysis for Chemical Structures of Residue by NMR

采用1 H-NMR和13 C-NMR,研究了渣油组分中各种类型碳的分布,尤其是芳碳的分类。在1 H-NMR中,具有化学位移6.0～9.0区间的质子对应的芳碳为质子芳碳,化学位移2.0～4.0区间的质子对应的芳碳为取代芳碳。在13 C-NMR中,化学位移10～70为饱和碳,化学位移120～130为质子芳碳和芳香内碳,化学位移130～150为取代芳碳和芳香并碳。关联了1 H-NMR和13 C-NMR中部分芳碳的数值对应关系,计算了渣油组分中各种碳的分率。结果表明,从芳香分、胶质到沥青质,饱和碳分率降低,芳碳分率增加,尤其是沥青质含有较多芳香内碳,其缩合最紧密。渣油经过加氢处理后,大部分胶质和沥青质被脱除,剩余部分饱和碳分率降低,芳碳分率增加,特别是芳香内碳分率增加,表明其中芳香环系的缩合程度更高。

1H-NMR and 13C-NMR were used to research the carbon types,especially classification aromatic carbon,in fractions from residue.The protons with chemical shift of 6.0-9.0 in 1H-NMR were assigned to corresponding proton aromatic carbon,and the protons with chemical shift of 2.0-4.0 were assigned to corresponding substituted aromatic carbon.Based on 13C-NMR,the carbons with chemical shift of 10-70 were assigned to saturated carbons,the carbons with chemical shift of 120-130 were assigned to proton aromatic carbon and inner aromatic carbon,the carbons with chemical shift of 130-150 were assigned to substituted aromatic carbon and merged aromatic carbon.The fractions of various carbon types in residue fractions were calculated by according to their 1H-NMR and 13C-NMR.The result showed that the saturated carbon percent decreased and the aromatic carbon percent increased from aromatics to resin and to asphaltene,especially,in asphaltene there were more inner aromatic carbons with the most compact condensed structure.Because resin and asphaltene were mostly removed during residue hydrotreating,the remains had lower saturated carbon fraction and higher aromatic carbon fraction.That inner aromatic carbon fraction increased indicated that asphaltene had more compact condensed aromatic rings.