ABSTRACT

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.