 |
Aromatization pathways for compounds of tropanes (Mackienze et al., 1982) and tropanes (Greiner et al., 1976, 1977; Spyckerelle et al., 1977)
Aromatization is an important process of diagenesis of organic compounds, forming naphthenic, phenanthrene and other cyclic aromatic compounds. The diagenetic aromatization products are often used as biomarker compounds for studying the thermal maturity of samples (Mackineze et al., 1981, 1982), among which the common aromatic hydrocarbons are monoarylethene and triarylphosphonium up to phenanthrene. Aromatized steranes are not common, and their aromatization studies are relatively rare.
Recently, Lu Hong and Liao Jing of the Guangzhou Institute of Geochemistry of the Chinese Academy of Sciences have discovered a large number of aromatized steranes in the kukersite oil shale in Estonia, including mono-, di-, tri-, and tetraaryl decane. The monomeric carbon isotopes of these aromatized nonanes and unaromatized nonanes were studied and compared, and the monomeric carbon isotopes of aromatized nonane and nonaromaticized terpenoids in the samples were also compared. The study explored the carbon isotope fractionation in the aromatization process.
The results show that the monomer carbon isotope becomes heavier in the process of aromatization of decane, but the monomer carbon isotope does not change during the aromatization of decane. This phenomenon can be reasonably explained from the basic chemical structure: Although the decane and decane in the aromatization process follow the six-membered ring cyclization and the five-membered ring does not cyclize, but in the monoaryl decane Only methylation at the C-19 position occurs during the formation process. Even if the triaryl decane loses only one carbon, the carbon isotope fractionation is not obvious; the decane aromatization process continuously loses C-28, C- 27. A total of 5 carbons on C-26, C-25, and C-24 or C-23, so it is normal and reasonable that the carbon isotope is weighed 2-4 。.
This aromatization in low-maturity Estonian oil shale obviously has nothing to do with the thermal maturation effect in diagenetic evolution and should be closely related to microbial activity. In combination with maternal input bioanalysis of the characteristic Gloeocapsomorpha Prisca (G. Prisca) in this oil shale, this microbial aromatization may be related to prokaryotic cyanobacteria. Therefore, the discovery of a large amount of aromatized decane is likely to indicate the presence of source input of prokaryotic cyanobacteria.
The research results were published in ENERGY & FUELS (Liao, Jing; Lu, Hong; Sheng, Guoying; Peng, Ping'an; Hsu, Chang Samuel. Monoaromatic, Diaromatic, Triaromatic, and Tetraaromatic Hopanes in Kukersite Shale and Their Stable Carbon Isotopic Composition. ENERGY & FUELS, 2015, 29(6): 3573-3583. DOI: 10.1021/acs.energyfuels.5b00106).
Best Fishing Pliers,Fishing Forceps,Fishing Tool With Diamond File,Classical Fishing Multitool
Easy-Go Outdoor Co.,Ltd. , https://www.yjeasy-go.com