Hydrodenitrogenation of Carbazole on Nitrided Molybdena-alumina Catalyst.

Abstract

The hydrodenitrogenation (HDN) of carbazole on the nitrided 12.5% MoO3/Al2O3 catalysts over a temperature range of 280-360℃ and at a total pressure range of 5-15MPa was studied. The 12.5% MoO3/Al2O3 was nitrided at various nitriding temperatures (500, 700 and 900℃), NH3 pressures (0.1 and 0.5MPa), and NH3 flow rates (4 and 15l h-1), following after the temperature-programmed reaction with NH3. After nitriding, the nitrided catalysts were cooled to room temperature in flowing NH3 and passivated with 1% O2/He for 12h. It was difficult to remove nitrogen from the catalysts nitrided at 700 and 900℃, even though the catalysts were evacuated at 700℃. The catalyst nitrided at 900℃ showed the highest activity among all catalysts in the HDN of carbazole, and that nitrided at 700℃ displayed the second highest activity. The activities of the catalysts nitrided and reduced at 500℃ showed similar values. Nitriding the MoO3/Al2O3 catalyst enhanced the C-N hydrogenolysis selectivity more than reducing the catalyst. The external mass transfer was negligible in the reaction. The formation of the denitrogenated compounds was on the order of 0.9 and 0.7 with respect to hydrogen in the range of 3-9MPa pressure and initial carbazole concentration of 0.023 to 0.35%, respectively. The sulfur compound inhibited the HDN of carbazole depending on its proton affinity. The XPS study showed that the molybdenum species between Mo4+ to Mo6+ ion were widely distributed and many nitrogen species, such as nitride-nitrogen, adsorbed NH3, and NHx, were present on the surface.

Exploring Complex Mixtures by Cyclic Ion Mobility High-Resolution Mass Spectrometry: Application Toward Petroleum

“…In this study, we explore the capabilities of cyclic IMS high-resolution mass spectrometry for the description of petrochemical sample materials with high isobaric and isomeric complexity. For this purpose, fossil vacuum gas oils (VGOs), a heavy residue of petroleum refining, were chosen. ,, Different types of experimental designs are presented. This manuscript is organized along the questions resulting from the isobaric and isomeric continuum: How far can we increase the isomeric separation capability for the direct infusion of petroleum?…”

“…For this purpose, fossil vacuum gas oils (VGOs), a heavy residue of petroleum refining, were chosen. 11,42,43 Different types of experimental designs are presented. This manuscript is organized along the questions resulting from the isobaric and isomeric continuum: How far can we increase the isomeric separation capability for the direct infusion of petroleum?…”

Kinetics toward mechanism and real operation for ultra‐deep hydrodesulfurization and hydrodenitrogenation of diesel

“…As a new emphasis, the research on the HDN and its competition with HDS is lacking, especially for carbazoles 13‐15 . While the reaction network for the HDN of carbazoles has long been established by Nagai et al 16 in 1980, by now a corresponding kinetic model has not been reported, which is not commensurate with the predominance of carbazoles in refractory diesel. Similarly, though the organonitrogen inhibition has been well‐studied, most of them were conducted in steady‐state and with little removal of organonitrogen species 17,18 .…”

Surface Properties and Active Sites of Nitrided Mo/Al2O3 Catalysts for the Hydrodenitrogenation of Carbazole

“…The HDN reaction on molybdenum sulfides has been extensively studied in terms of further development of NiMo and CoMo sulfides with additives containing phosphorus and fluorine, competitive reaction with HDS and the effect of the generated H 2 S, and the active surface sites [1][2][3][4][5][6][7][8][9][10]. In recent years, new types of catalyst, such as transition metal nitrides and oxynitrides [11][12][13][14] have been studied for hydrotreatment [15][16][17], HDS [18][19][20][21][22][23] and HDN [24][25][26][27][28][29][30][31][32][33][34]. Molybdenum nitrides with a high surface area have been extensively developed by the temperature-programmed nitridation of MoO 3 with ammonia [35][36][37][38][39] or N 2 ?…”

“…Additionally, phosphorus-doped tungsten oxynitride has been prepared from heteropolyanion precursors [48]. Attention has been directed to a number of different areas, including (1) the preparation of bimetallic nitride catalysts, such as Co, Ce, Ti, and Zr-doped Mo nitrides with higher HDN activities than the pure c-Mo 2 N catalyst [42,[49][50][51][52]; (2) the specific reactivity of nitrogen compounds, such as indole [26,31], pyridine [30,[32][33][34], quinoline [24] and carbazole [25,28,29], on Mo 2 N and promoted Mo 2 N/Al 2 O 3 catalysts for C-N hydrogenolysis; (3) the activities of bulk molybdenum nitride and nitrided Mo/Al 2 O 3 in comparison to sulfided catalysts for HDN [28,53] (in the latter case, nitrides are more active), although molybdenum sulfide and sulfided NiMo/c-Al 2 O 3 catalysts were more active than the corresponding nitride for the HDN and HDS of coal-derived naphtha [17] and the light gas and heavy gas oils [54], respectively, at higher temperatures ([598 K)); (4) the kinetics of the Mo 2 N/Al 2 O 3 catalyst for HDN [22,55,56] including the competitive reaction with HDS and the effects of additives and catalyst deactivation [22,54,57]; and (5) the active surface sites on Mo 2 N/Al 2 O 3 catalysts which have been studied using XPS [55,[58][59][60], NMR [61,62], the temperature-programmed desorption(TPD)/temperature-programmed surface reaction with hydrogen (TPSR) [58,[63][64][65]…”