Us. Ozkan et al., SIMULTANEOUS HYDRODESULFURIZATION AND HYDRODENITROGENATION OF MODEL COMPOUNDS OVER NI-MO GAMMA-AL2O3 CATALYSTS/, Energy & fuels, 8(1), 1994, pp. 249-257
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.