Elucidation of hydrodesulfurization mechanism on molybdenum‐based catalysts using 35S radioisotope pulse tracer methods

Abstract

Elucidation of the hydrodesulfurization (HDS) mechanism on molybdenum‐based catalysts using radioisotope tracer methods and reaction kinetics is reviewed. Firstly, to investigate the sulfidation state in Mo/Al2O3 and Co–Mo/Al2O3 catalysts, presulfiding of these catalysts has been performed using a 35S pulse tracer method. Secondly, HDS of radioactive 35S‐labeled dibenzothiophene was carried out over a series of sulfided molybdena–alumina catalysts and cobalt‐promoted molybdena–alumina catalysts in a pressurized flow reactor to estimate the behavior of sulfur on the working catalysts. Finally, sulfur exchange of a 35S‐labeled catalyst with hydrogen sulfide was performed to estimate the relationship between the amount of labile sulfur and catalytically active sites.