SIMULTANEOUS HYDRODESULFURIZATION AND HYDRODENITROGENATION OF MODEL COMPOUNDS OVER NI-MO GAMMA-AL2O3 CATALYSTS/

In spite of the recognized importance of their industrial application, the questions regarding catalytic phenomena involved in hydrodenitrog enation (HDN) reactions still remain unanswered. In this study, gamma- Al2O3-supported Ni, Mo, and bimetallic Ni-Mo catalysts were used for i nvestigating the pyridine HDN and the,simultaneous pyridine HDN/thioph ene HDS reactions. The purpose of this study was to investigate the ro le of Ni as a promoter in the Ni-Mo catalyst system and to examine the effect of the presence of sulfur-containing compounds in the gas phas e on HDN reaction. The results showed the C-5 yield to be a strong fun ction of the Mo loading regardless of whether Ni was added to Mo or no t, whereas the piperidine yield showed no dependence on Mo loading. Th e findings of this study, when combined with the catalyst characteriza tion results, lead us to suggest that Mo active species promote hydrog enolysis of piperidine while Ni-Mo species enhance the hydrogenation o f pyridine. The experimental results also show the enhancement effect of the presence of sulfur-containing compounds on HDN, especially when Ni is combined with Mo.