Hydrodenitrogenation of Quinoline Catalyzed by MCM-41-Supported Nickel Phosphides

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• 作者：Mohong Lu ; Anjie Wang ; Xiang Li ; Xinping Duan ; Yang Teng ; Yao Wang ; Chunshan Song ; Yongkang Hu
• 刊名：Energy & Fuels
• 出版年：2007
• 出版时间：March 2007
• 年：2007
• 卷：21
• 期：2
• 页码：554 - 560
• 全文大小：337K
• 年卷期：v.21,no.2(March 2007)
• ISSN：1520-5029

文摘

A series of MCM-41-supported nickel phosphides with an initial Ni/P atomic ratio of 0.5-2 in the oxidicprecursors were prepared by an in situ reduction method and characterized by X-ray diffraction (XRD), COchemisorption, N₂ adsorption, and transmission electron microscopy. Their catalytic performances were evaluatedin the hydrodenitrogenation (HDN) of quinoline and compared with MCM-41-supported Ni-Mo sulfide. Thesupported nickel phosphides with initial Ni/P ratios of 1 or 1.25 exhibited much higher HDN activity than thesupported Ni-Mo sulfide. XRD patterns of both high-performance phosphide catalysts revealed that the activephase was Ni₂P. It is indicated that the HDN of quinoline on the MCM-41-supported nickel phosphidesexclusively proceeds via a pathway, which involves fully saturated intermediates. The cleavage of the C-Nbond in the decahydroquinoline is the rate-determining step in the HDN of quinoline on the supported nickelphosphides. In addition, the effects of H₂S (CS₂ as the precursor) on HDN and the performances of the preparednickel phosphide catalysts in the simultaneous HDN of quinoline and hydrodesulfurization (HDS) ofdibenzothiophene (DBT) were investigated. The presence of H₂S dramatically reduced the hydrogenation of1,2,3,4-tetrahydroquinoline to decahydroquinoline, altering unfavorably the reaction pathways involved in theHDN of quinoline. The simultaneous HDN and HDS indicated that the HDN activity of Ni-Mo sulfide washardly affected in the presence of DBT. Whereas, the supported nickel phosphide was sensitive to the presenceof DBT at low temperatures. It is favorable to perform HDN at high temperatures because the inhibitingeffects of H₂S and DBT on HDN were dramatically reduced at elevated temperatures.