TY - JOUR
T1 - Influence of nitrogen compounds on deep hydrodesulfurization of 4,6-dimethyldibenzothiophene over Al2O3- and MCM-41-supported Co-Mo sulfide catalysts
AU - Turaga, Uday T.
AU - Ma, Xiaoliang
AU - Song, Chunshan
N1 - Funding Information:
This work was supported in part by the US Department of Energy and the US Air Force Office of Scientific Research. The authors are grateful to Mr. Gang Wang and Professor Harold H. Schobert for useful discussions. The authors also wish to thank the two anonymous reviewers for providing helpful comments.
PY - 2003/11/1
Y1 - 2003/11/1
N2 - The present work focuses on the effect of nitrogen compounds on the activity of MCM-41- and γ-Al2O3-supported Co-Mo catalysts for the deep hydrodesulfurization of 4,6-dimethyldibenzothiophene (4,6-DMDBT) in a fixed-bed flow reactor. Sulfur removal to the depths required by new specifications will require knowledge of the influence of non-sulfur diesel fuel components on deep hydrodesulfurization. The main objective of this paper is to examine the activity of hydrodesulfurization catalysts during and, most importantly, after exposure to basic and non-basic nitrogen. Quinoline (basic nitrogen) inhibits catalytic activity of both γ-Al 2O3- and MCM-41-supported catalysts. It strongly inhibits hydrogenation and hydrogenolysis activity as evidenced by decreased selectivity for cyclohexylbenzene and biphenyl derivatives, respectively. To a certain extent, the long-term effects of quinoline are reversible. Carbazole (non-basic nitrogen) has little effect on the γ-Al2O 3-supported Co-Mo catalyst but significantly inhibits the activity of the MCM-41-supported Co-Mo catalyst. The inhibition of the MCM-41-supported catalyst is reversible following removal of carbazole from the feedstock. Molecular modeling was also conducted to derive the bond order and electron charges of the nitrogen and sulfur compounds, which are helpful to understanding the experimental results.
AB - The present work focuses on the effect of nitrogen compounds on the activity of MCM-41- and γ-Al2O3-supported Co-Mo catalysts for the deep hydrodesulfurization of 4,6-dimethyldibenzothiophene (4,6-DMDBT) in a fixed-bed flow reactor. Sulfur removal to the depths required by new specifications will require knowledge of the influence of non-sulfur diesel fuel components on deep hydrodesulfurization. The main objective of this paper is to examine the activity of hydrodesulfurization catalysts during and, most importantly, after exposure to basic and non-basic nitrogen. Quinoline (basic nitrogen) inhibits catalytic activity of both γ-Al 2O3- and MCM-41-supported catalysts. It strongly inhibits hydrogenation and hydrogenolysis activity as evidenced by decreased selectivity for cyclohexylbenzene and biphenyl derivatives, respectively. To a certain extent, the long-term effects of quinoline are reversible. Carbazole (non-basic nitrogen) has little effect on the γ-Al2O 3-supported Co-Mo catalyst but significantly inhibits the activity of the MCM-41-supported Co-Mo catalyst. The inhibition of the MCM-41-supported catalyst is reversible following removal of carbazole from the feedstock. Molecular modeling was also conducted to derive the bond order and electron charges of the nitrogen and sulfur compounds, which are helpful to understanding the experimental results.
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U2 - 10.1016/S0920-5861(03)00464-4
DO - 10.1016/S0920-5861(03)00464-4
M3 - Article
AN - SCOPUS:0141929338
SN - 0920-5861
VL - 86
SP - 265
EP - 275
JO - Catalysis Today
JF - Catalysis Today
IS - 1-4
ER -