103272-52-2Relevant articles and documents
Hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and their hydrogenated intermediates over Ni-MoS2/γ-Al2O3
Wang, Huamin,Prins, Roel
, p. 31 - 43 (2009)
The rate constants of all reaction steps in the hydrodesulfurization (HDS) of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), and their tetra- and hexahydro intermediates TH(DM)DBT and HH(DM)DBT over Ni-MoS2/γ-Al2O
Regioselective addition of atomic hydrogen to olefins. Reversible 1-methyl-5-hexenyl radical cyclization in the solution-phase hydrogenation
Tanner, Dennis D.,Zhang, Liying
, p. 6683 - 6689 (1994)
The solution-phase reactions of microwave-generated hydrogen atoms with terminal olefins is regioselective. Since addition is to the terminal end of the olefin, the reaction yields a secondary radical which undergoes either reaction with molecular or atomic hydrogen, disproportionation, combination, or addition to another olefin, and in the case of hydrogen atom addition to 1,6-heptadiene, cyclization. The cyclized radicals are formed reversibly, and the final product mixture contains only minor amounts of cis-1,2-dimethylcyclopentane (the product of kinetic control) while the major cyclized product is methylcyclohexane. Although an equilibrium mixture could not be obtained, the dimethylcyclopentyl and 3-methylcyclohexyl radicals were shown to be formed reversibly.
Hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene over sulfided NiMo/γ-Al2O3, CoMo/γ-Al 2O3, and Mo/γ-Al2O3 catalysts
Egorova, Marina,Prins, Roel
, p. 417 - 427 (2004)
The hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was studied over sulfided NiMo/γ-Al2O3, CoMo/γ-Al2O 3, and Mo/γ-Al2O3 catalysts. The Ni and Co promoters strongly enhanced the activity of the Mo catalyst in the direct desulfurization pathway of the HDS of DBT and 4,6-DMDBT and in the final sulfur-removal step in the hydrogenation pathway, while the hydrogenation was moderately promoted. H2S had a negative effect on the HDS of DBT and 4,6-DMDBT, which was strongest for the NiMo catalyst and stronger for the direct desulfurization pathway than for the hydrogenation pathway. Because the direct desulfurization pathway is less important for the HDS of 4,6-DMDBT than the hydrogenation pathway, the conversion of 4,6-DMDBT was less affected by H 2S than the conversion of DBT. The sulfur removal via the direct desulfurization pathway and the ultimate sulfur removal in the hydrogenation pathway were affected by H2S to the same extent over all the catalysts. This suggests that the removal of sulfur from tetrahydrodibenzothiophenes takes place by hydrogenolysis, like the direct desulfurization of DBT to biphenyl. The CoMo catalyst performed better than the NiMo catalyst in the final desulfurization via the hydrogenation pathway in the HDS of 4,6-DMDBT at all partial pressures of H2S.
Palladium islands on iron oxide nanoparticles for hydrodesulfurization catalysis
Mansouri, Ali,Semagina, Natalia
, p. 2323 - 2332 (2018)
A four-fold increase in palladium (Pd) mass-based hydrodesulfurization (HDS) activity was achieved by depositing Pd species as nanosized islands on 12 nm colloidal iron oxide (FeOx) nanoparticles via the galvanic exchange reaction. The highest palladium dispersion was obtained at an optimal Pd/Fe molar ratio of 0.2, which decreased when the ratio increased. The improved dispersion was responsible for the enhanced catalytic activity per the total Pd amount in the HDS of 4,6-dimethyldibenzothiophene at 623 K and 3 MPa as compared to the iron-free Pd/Al2O3 catalyst. The lattice strain and modified electronic properties of the Pd islands suppressed deep hydrogenation to dimethylbicyclohexyl and changed the hydrocracking product distribution. Pd nanoparticles deposited on commercial Fe2O3 did not provide such an activity enhancement and catalyzed significant cracking. This study demonstrates that FeOx@Pd structures are a possible alternative to monometallic Pd catalysts with enhanced noble metal atom efficiency for ultra-deep HDS catalysis and points to their great potential to reduce the catalyst cost and move towards more earth-abundant catalytic materials.
Effect of citric acid addition on the morphology and activity of Ni2P supported on mesoporous zeolite ZSM-5 for the hydrogenation of 4,6-DMDBT and phenanthrene
Zhang, Lei,Fu, Wenqian,Yu, Quanyong,Tang, Tiandi,Zhao, Yicheng,Li, Yongdan
, p. 295 - 307 (2017)
Preparing small, highly dispersed Ni2P particles is important for improving the hydrogenation ability of Ni2P. Here, Ni2P nanoparticles (approximately 4.3 nm) on mesoporous zeolite ZSM-5 (Ni2P/MZSM-5-CA) were prepared using citric acid (CA) as an assistant agent. The formation mechanism of small Ni2P particles when CA was added was investigated by combining UV–vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and temperature-programmed reduction with a transmission electron microscope and CO chemisorption. The results indicated that the formed CA–Ni complex with high viscosity favors the Ni precursor dispersed on the dried catalyst. After calcination, the released Ni species strongly interacted with surface acidic hydroxyl groups on MZSM-5, leading to the formation of Ni2P particles with small sizes and good dispersion under a reducing atmosphere. The reaction rate constants and TOFs over Ni2P/MZSM-5-CA (16.2 × 10?2μmol g?1s?1and 9.7 × 10?4s?1) are much higher than over Ni2P/MZSM-5 (8.2 × 10?2μmol g?1s?1and 8.3 × 10?4s?1) in 4,6-dimethyldibenzothiophene hydrodesulfurization. In addition, Ni2P/MZSM-5-CA catalyst shows higher activity than Ni2P catalyst without CA in phenanthrene hydrogenation.
Synthesis of highly ordered TiO2-Al2O3 and catalytic performance of its supported NiMo for HDS of 4, 6-dimethyldibenzothiophene
Liu, Xiaodong,Long, Yuchi,Mu, Fujun,Shan, Yacheng,Wei, Qiang,You, Qingxiang,Zhang, Pengfei,Zhou, Wuwen,Zhou, Yasong
, (2020)
The highly ordered mesoporous TiO2-Al2O3 composite oxides were prepared via a facile evaporation-induced self-assembly (EISA) method. All of those synthesized materials were characterized by means of XRD, XRF, N2 adsorption, FTIR, Py-FTIR and TEM. The results show that the hexagonally ordered mesoporous TiO2-Al2O3 oxides with high specific surface area, high thermal stability and narrow pore size distributions were successfully synthesized by EISA. The corresponding NiMo catalysts supported on TiO2-Al2O3 oxides were further characterized by H2-TPR, HRTEM and XPS. Their hydrodesulfurization catalytic performances were tested in a fixed-bed reactor, using 4,6-dimethyldibenzothiophene as the probe. The analyzing results exhibit that the incorporation of TiO2 could effective weaken the support-metal interactions, thus enhancing the reduction degree of active metals and forming more “Type II” Ni-Mo-S active phases that would be beneficial for the HDS of highly refractory organosulfur compound. The catalytic results reveal that the 4,6-DMDBT conversion over NiMo/TA-n catalysts gradually increased as the Ti/Al molar ratio increases, and reaches a maximum values at NiMo/TA-0.4. The NiMo/TA-0.4 exhibited the highest hydrodesulfurization catalytic performance of 4,6-DMDBT due to the synergistic effect of suitable textural properties, high thermal stability and moderate metal-support interactions.
Hydrodesulfurization enhancement of heavy and light S-hydrocarbons on NiMo/HMS catalysts modified with Al and P
Zepeda,Infantes-Molina,Díaz De León,Fuentes,Alonso-Nú?ez,Torres-Ota?ez,Pawelec
, p. 108 - 121 (2014)
Deep hydrodesulfurization (HDS) of oil fractions is a key process in petroleum refineries due to the increasing demand for S-free diesel and gasoline fractions. In this work, a series of NiMo catalysts supported on Al- and P-modified HMS mesoporous substrate were tested in the HDS of thiophene and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to evaluate the effect of Al and P additives on the catalyst response in HDS reactions (thiophene at 1 bar and 4,6-DMDBT at 5.5 MPa). The catalysts were characterized by a variety of techniques (XRD, N2 adsorption-desorption, TPR, TPS, FT-IR of adsorbed pyridine, UV-vis and H2 chemisorption). NiMo/Al-HMS-P catalyst containing 1.0 wt.% of P exhibited the best performance in both HDS reactions as a consequence of the proper balance between the active phase dispersion and the largest hydrogenation ability among the studied catalysts. The 4,6-DMDBT HDS reaction proceeded toward direct desulfurization (DDS) and hydrogenation (HYD) reaction routes. Concerning the HDS of thiophene, the increase of the catalyst acidity led to the formation of butadiene and diminished the hydrogenation of olefins (formation of butane). At the reaction temperature of 320 °C, the NiMo/Al-HMS-P1.0 catalyst exhibited the highest activity and the lowest butane formation among the catalysts studied. The isomerization of olefins in the thiophene HDS reaction did not occur, in line with the observed absence of isomerization in the 4,6-DMDBT HDS reaction.
Self-Assembly of Hierarchically Porous ZSM-5/SBA-16 with Different Morphologies and Its High Isomerization Performance for Hydrodesulfurization of Dibenzothiophene and 4,6-Dimethyldibenzothiophene
Wang, Xilong,Mei, Jinlin,Zhao, Zhen,Zheng, Peng,Chen, Zhentao,Gao, Daowei,Fu, Jianye,Fan, Jiyuan,Duan, Aijun,Xu, Chunming
, p. 1891 - 1902 (2018)
ZSM-5/SBA-16 (ZS) composite materials with different morphologies were synthesized successfully. The series supports were utilized to prepare NiMo/ZS for dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) reactions. Series ZS supports and NiMo/ZS were well characterized to investigate their structure-property relationship. The NiMo/ZS catalyst (NiMo/ZS-3) with uniform morphology and well-ordered pore channels showed the maximum kHDS and TOF values of DBT and 4,6-DMDBT HDS. The kHDS value (13.9 × 10-4 mol g-1 h-1) of DBT over NiMo/ZS-3 was more than 2 times greater than that over the reference NiMo/ZS-M catalyst (5.5 × 10-4 mol g-1 h-1), 3 times greater than that over the NiMo/SBA-16 catalyst (4.4 × 10-4 mol g-1 h-1), and almost 4 times greater than that over the NiMo/ZSM-5 catalyst (3.5 × 10-4 mol g-1 h-1). Furthermore, the kHDS value (8.4 × 10-4 mol g-1 h-1) of 4,6-DMDBT over NiMo/ZS-3 was more than 3 times greater than that over the reference NiMo/ZS-M catalyst (2.8 × 10-4 mol g-1 h-1), more than 4 times greater than that over the NiMo/SBA-16 catalyst (1.7 × 10-4 mol g-1 h-1), and almost 5 times greater than that over the NiMo/ZSM-5 catalyst (1.6 × 10-4 mol g-1 h-1). The superior DBT and 4,6-DMDBT HDS performances were assigned to the uniform morphology, well-ordered pore channels, and high B/L ratio of the NiMo/ZS-3 catalyst and the suitable dispersion of the MoS2 active phases. HYD was the preferential route for DBT HDS, while ISO was the preferential route for 4,6-DMDBT HDS because of the high B/L ratio of NiMo/ZS-3. Moreover, the DBT and 4,6-DMDBT HDS reaction networks of the series NiMo/ZS are presented.
Effect of the amount of citric acid used in the preparation of NiMo/SBA-15 catalysts on their performance in HDS of dibenzothiophene-type compounds
Calderón-Magdaleno, Miguel ángel,Mendoza-Nieto, Juan Arturo,Klimova, Tatiana E.
, p. 78 - 88 (2014)
In the present work, NiMo catalysts supported on SBA-15 were prepared with the addition of different amounts of citric acid (CA) in the impregnation solutions. The aim of this study was to inquire into the effect of the amount of citric acid on the activity and selectivity of the NiMo/SBA-15 catalysts in deep hydrodesulfurization (HDS). Catalysts were prepared by coimpregnation of Ni and Mo species from acidic aqueous solutions containing citric acid without further adjusting the solution's pH. The amount of citric acid used in the catalyst preparation was varied from CA:Mo molar ratio 0.5 to 2.0. In addition, a reference NiMo/SBA-15 catalyst was prepared without citric acid. After the impregnation, catalysts were dried (100 C, 6 h) and calcined (500 C, 4 h). The prepared catalysts were characterized by nitrogen physisorption, small-angle and powder X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), temperature-programmed reduction (TPR), high resolution transmission electron microscopy (HRTEM) and tested in simultaneous HDS of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in a batch reactor at 300 C for 8 h. XRD, DRS and TPR characterizations showed that Ni and Mo oxide species were well dispersed in all catalysts prepared with CA. In contrast, a NiMoO4 crystalline phase was detected by XRD in the reference NiMo/SBA-15 catalyst prepared without citric acid. Addition of citric acid to the impregnation solutions used for the catalyst preparation also resulted in an increase in the degree of sulfidation and in the dispersion of catalytically active MoS 2 phase (elemental analysis, HRTEM). In accordance with this, HDS activity of the NiMo catalysts prepared with the addition of citric acid resulted to be significantly higher than that of the reference NiMo/SBA-15 sample for both sulfur-containing compounds tested (DBT and 4,6-DMDBT). It was found that the optimum amount of citric acid, which allows achieving the highest catalytic activity, corresponds to CA:Mo molar ratio equal to 1. Further increase in the amount of citric acid resulted in a slight decrease in the HDS activity. Regarding selectivity, addition of small amounts of CA, in general, resulted in an increase of the hydrogenation ability of the NiMo/SBA-15 catalysts. However, some differences in the selectivity of the catalysts were observed with different amounts of citric acid used.
Kinetics of the HDS of 4,6-dimethyldibenzothiophene and its hydrogenated intermediates over sulfided Mo and NiMo on γ-Al2O3
Li, Xiang,Wang, Anjie,Egorova, Marina,Prins, Roel
, p. 283 - 293 (2007)
To study the hydrodesulfurization (HDS) reaction network of 4,6-dimethyldibenzothiophene (DMDBT), three hydrogenated intermediates-tetrahydro-, hexahydro-, and dodecahydro-DMDBT-were synthesized, and their HDS was investigated over sulfided Mo and NiMo on γ-Al2O3 catalysts at 300 °C and 5 MPa. Tetrahydro-DMDBT reacted by hydrogenation to hexahydro-DMDBT, which in turn reacted to dodecahydro-DMDBT by hydrogenation and to 3,3′-dimethylcyclohexylbenzene by desulfurization. All four diastereoisomers of hexahydro-DMDBT were observed, all of which interconverted rapidly during HDS. Dodecahydro-DMDBT reacted by desulfurization to 3,3′-dimethylbicyclohexyl. The rate constants of all steps in the kinetic network of the HDS of DMDBT could be measured over Mo/γ-Al2O3, and those of some steps could be measured over NiMo/γ-Al2O3. The first step-hydrogenation of DMDBT to tetrahydro-DMDBT-is the slowest, rate-determining step, but the hydrogenation of and the sulfur removal from hexahydro-DMDBT are also slow. Opening of the sulfur-containing ring in DMDBT and its hydrogenated intermediates occurs by C{single bond}S hydrogenolysis rather than by elimination.
Ultradeep hydrodesulfurization of fuel over superior NiMoS phases constructed by a novel Ni(MoS4)2(C13H30N)2precursor
Fan, Yu,He, Shuisen,Wen, Chenglong,Xu, Jundong
, p. 6065 - 6075 (2020)
This article presents novel decyltrimethylammonium bromide-dispersed Ni-Mo sulfide (DTMA-NiMo) as a precursor for preparing an efficient NiMoS/γ-Al2O3hydrodesulfurization (HDS) catalyst. The as-synthesized DTMA-NiMo is a sulfide containing both long-chain quaternary ammonium and Ni-Mo-S elements. The proposed method not only significantly improves the dispersion of Mo species but also greatly promotes the incorporation of Ni into MoS2slabs, leading to an increase in the number of NiMoS phases. As a result, the DTMA-NiMo-based NiMoS/γ-Al2O3catalyst exhibits much higher activity for the HDS of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and fluid catalytic cracking (FCC) diesel than NiMoS/γ-Al2O3catalysts prepared by the co-impregnation and tetrapropylammonium bromide (TPAB)-assisted methods. This novel strategy sheds a light on the facile and low-cost preparation of superior NiMoS phases without sulfidation treatment.
A new type of nonsulfide hydrotreating catalyst: Nickel phosphide on carbon
Shu, Yuying,Oyama, S. Ted
, p. 1143 - 1145 (2005)
Nickel phosphide on carbon is successfully synthesized by temperature-programmed reduction as verified with X-ray diffraction and extended X-ray absorption fine structure measurements; it shows superior activity, selectivity, and stability for sulfur removal from the refractory compound 4,6-dimethyldibenzothiophene with a steady-state conversion of 99%, which is much higher than that of a commercial NiMoS/γ-Al2O3 catalyst of 68%. The Royal Society of Chemistry 2005.
