Influence of organic-inorganic interactions on the preservation of sedimentary organic nitrogen: A preliminary experimental study

• Published in: GEOCHEMICAL JOURNAL Vol. 46; no. 4; pp. e33 - e37
• Main Authors: DING, KANGLE, LUO, YUE, SHAN, JINGFU, GUAN, FUJIA
• Format: Journal Article
• Language: English
• Published: GEOCHEMICAL SOCIETY OF JAPAN 2012
• Subjects: alteration; N-S atom exchange; organic-inorganic interaction; pyrrolic N compound
• ISSN: 0016-7002; 1880-5973
• DOI: 10.2343/geochemj.2.0217

Experiments simulating reactions between pyrrole, hydrogen sulfide (H2S), and aluminum oxide (Al2O3) using a dynamic thermochemical process simulator were conducted to investigate the effect of organic-inorganic interactions on pyrrolic N compounds. The results showed that N-S atomic exchange occurred at 350°C with thiophene as the main product. Thermodynamic studies indicated the reaction of pyrrole with H2S could proceed spontaneously in most geologic settings (0-200°C). Thermochemical conversion of pyrrole into thiophene was found to be catalyzed by Al2O3 but inhibited by an increased volume of water. These findings suggest that conventional models may not fully account for the geochemical processes that result in the abundance and distribution of pyrrolic N compounds in sediments and crude oils. The organic-inorganic interactions in sedimentary basins may also have direct effects on the fate and preservation of pyrrolic N compounds in subsurface reservoirs.