Chemical structure of bitumen-derived asphaltenes by nuclear magnetic resonance spectroscopy and X-ray diffractometry

✍ Scribed by Jayaraj Christopher; Amarjeet S. Sarpal; Gurpreet S. Kapur; Agadi Krishna; Babu R. Tyagi; Mukesh C. Jain; Surendra K. Jain; Akhilesh K. Bhatnagar

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 939 KB
• Volume: 75
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(96)00023-3

✦ Synopsis

Asphaltene samples obtained from bitumen processed at three Indian refineries were characterized for chemical composition and structure by nuclear magnetic resonance (n.m.r.) spectroscopy and X-ray diffractometry (XRD). The average structural parameters were obtained by combined 1H, 13C and DEPT spectral editing techniques. New equations were used for the estimation of n.m.r, average structure parameters. The macrostructure and crystalline parameters of these samples were obtained by XRD. A combined n.m.r, and XRD procedure was used to estimate the size of the average aromatic structural unit. Asphaltenes from one of the bitumens (ASP-D) was found to have different structural parameters from those of the asphaltenes from the other two bitumens. The number of aromatic rings per unit sheet in ASP-D was eight, compared with 13 for both ASP-M and ASP-H. XRD data indicated that the aromatic sheets are randomly oriented in ASP-D. The structural parameters allowed a model structure of the asphaltenes to be constructed.