Comparative characteristics of low-molecular nitrogen bases in sulfur rich natural asphaltite and the products of its conversion in supercritical water

• Main Authors: Antipenko, Vladimir R., Yanovskaya, Svetlana S., Fedyaeva, Oxana N., Vostrikov, Anatoly A.
• Format: Conference Proceeding
• Language: English
• Subjects: Additives; Aluminum; Aromatic compounds; Asphaltenes; Carbazoles; Conversion; Homology; Nitrogen; Nitrogen compounds; Polymers; Resins; Sulfur
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5083264

The paper deals with the results on the study of distribution and composition of nitrogen compounds, particularly low-molecular nitrogen bases in the components of sulfur rich natural asphaltite and the products of its conversion in supercritical water at 400°C, 30 MPa without any additives and in the presence of aluminum and zinc. Decrease in the content ratio of nitrogen in all variants of conversion is usually ranged as follows: insoluble conversion residue (ICR) > liquid product (LP) > volatile product (VP). About 50% of nitrogen compounds convert into ICR even at a sharp decrease in ICR yield in the presence of metal additives. The components isolated from conversion LP are usually characterized by higher nitrogen contents as compared with asphaltite components. In comparison with asphaltite, the pattern of nitrogen distribution over the components of LP changes significantly. A higher yield in extracts of nitrogen bases (NB) as compared with the initial asphaltite suggests a generation of additional portion of low-molecular NB due to the destruction of asphaltenes and resins contained in asphaltite during its conversion. The extracts contain much more aromatic compounds and their molecules have lower numbers of alkyl substituents. The contents of neutral NC (carbazoles and benzocarbazoles) and basic (benzoquinolines, dibenzoquinolines, azapyrenes, and benzoazapyrenes) are several-fold higher in the products obtained in the presence of aluminum additives. In addition, a sharp increase in unsubstituted structures among the above mentioned NC is observed in the same samples as compared with homologues. This is apparently due to the fact that the structural fragments in asphaltenes and resins are mainly linked by biphenyl bonds or via methylene or sulfide bridges.