493-02-7Relevant articles and documents
Low temperature catalytic hydrogenation naphthalene to decalin over highly-loaded NiMo, NiW and NiMoW catalysts
Liu, Huan,Liu, Chenguang,Yin, Changlong,Liu, Bin,Li, Xuehui,Li, Yanpeng,Chai, Yongming,Liu, Yunqi
, p. 46 - 54 (2016)
Hydrogenation of naphthalene to decalin at low temperatures (140–240 °C) was studied over highly-loaded sulfided NiMo, NiW, and NiMoW catalysts with a supported NiMo/γ-Al2O3 catalyst as comparison. The NiMo, NiW, and NiMoW catalyst precursors were synthesized by hydrothermal reactions, and the corresponding highly-loaded catalysts were made by mixing the precursors with an alumina gel. The catalyst precursors, oxide and sulfided highly-loaded catalysts were characterized by XRD, N2 adsorption-desorption, SEM, and TPR techniques. A highly crystalline phase of ammonium nickel molybdate was detected on the NiMo precursor, and the NiW precursor exhibited sharp XRD peaks attributed to a phase of hydrated tungsten oxide. Typical Ni3S2 and MoS2/WS2 nanoparticles were observed over the sulfided highly-loaded catalysts, and a main reduction peak was detected due to nickel sulfide as revealed by TPR. Catalytic results showed that more than 99.0% of naphthalene was hydrogenated over the sulfided highly-loaded catalysts at 200 °C or higher temperatures, with a very high selectivity to decalin (more than 99.9%) during the same temperature regions over the NiMo and NiMoW catalysts. As a comparison, the reference NiMo/γ-Al2O3 catalyst showed a moderate hydrogenation activity with a naphthalene conversion of 49.6% and a decalin selectivity of 40.1% at 300 °C. The ratios of trans- to cis-decalin on the highly-loaded catalysts and on the NiMo/γ-Al2O3 catalysts varied.
Tuning of activity and selectivity of Ni/(Al)SBA-15 catalysts in naphthalene hydrogenation
Vargas-Villagrán,Ramírez-Suárez,Ramírez-Mu?oz,Calzada,González-García,Klimova
, p. 27 - 37 (2019/09/30)
The hydrogenation of naphthalene was performed with nickel catalysts (4 wt. % of Ni) supported on SBA-15 and Al-SBA-15 in order to evaluate the effect of the support's acidity on the activity and selectivity of the catalysts. The incorporation of aluminum into the SBA-15 support was performed during the hydrothermal synthesis of the material with the aim to reach the isomorphic substitution of Si4+ by Al3+ leading to the generation of Br?nsted acid sites. Two different precursors (nickel nitrate and a Ni:EDTA complex) were used for the preparation of the catalysts on each support. Catalysts were characterized by nitrogen physisorption, powder X-ray diffraction, temperature programmed reduction, temperature programmed desorption of ammonia, scanning and high-resolution transmission electron microscopy. The Al-SBA-15 support was characterized by solid state 27Al MAS-NMR. The results showed that the intrinsic activity of the catalysts (TOF) increased when the Al-SBA-15 support and the Ni:EDTA complex were used in the catalyst's preparation. The catalysts prepared using the Ni:EDTA complex showed high selectivity to decalins and higher proportion of trans-decalin in the products than the catalysts prepared with nickel nitrate, which was attributed to a higher dispersion of the metallic Ni species and the larger total amount of acid sites.
Aromatic compound hydrogenation and hydrodeoxygenation method and application thereof
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Paragraph 0094-0095; 0106-0113, (2021/05/29)
The invention belongs to the technical field of medicines, and discloses an aromatic compound hydrogenation and hydrodeoxygenation method under mild conditions and application of the method in hydrogenation and hydrodeoxygenation reactions of the aromatic compounds and related mixtures. Specifically, the method comprises the following steps: contacting the aromatic compound or a mixture containing the aromatic compound with a catalyst and hydrogen with proper pressure in a solvent under a proper temperature condition, and reacting the hydrogen, the solvent and the aromatic compound under the action of the catalyst to obtain a corresponding hydrogenation product or/and a hydrodeoxygenation product without an oxygen-containing substituent group. The invention also discloses specific implementation conditions of the method and an aromatic compound structure type applicable to the method. The hydrogenation and hydrodeoxygenation reaction method used in the invention has the advantages of mild reaction conditions, high hydrodeoxygenation efficiency, wide substrate applicability, convenient post-treatment, and good laboratory and industrial application prospects.
Discovery of a Neutral 40-PdII-Oxo Molecular Disk, [Pd40O24(OH)16{(CH3)2AsO2}16]: Synthesis, Structural Characterization, and Catalytic Studies
Bhattacharya, Saurav,Bons, Anton-Jan,Cadot, Emmanuel,Espenship, Michael Forrester,Haouas, Mohamed,Jaensch, Helge,Kortz, Ulrich,Laskin, Julia,Ma, Xiang,Mougharbel, Ali S.,Stuerzer, Tobias,Su, Pei,Taffa, Dereje H.,Wark, Michael
, p. 17339 - 17347 (2021/11/17)
We report on the synthesis and structural characterization of a giant, discrete, and neutral molecular disk, [Pd40O24(OH)16{(CH3)2AsO2}16] (Pd40), comprising a 40-palladium-oxo core that is capped by 16 dimethylarsinate moieties, resulting in a palladium-oxo cluster (POC) with a diameter of μ2 nm. Pd40, which is the largest known neutral Pd-based oxo cluster, can be isolated either as a discrete species or constituting a 3D H-bonded organic-inorganic framework (HOIF) with a 12-tungstate Keggin ion, [SiW12O40]4- or [GeW12O40]4-. 1H and 13C NMR as well as 1H-DOSY NMR studies indicate that Pd40 is stable in aqueous solution, which is also confirmed by ESI-MS studies. Pd40 was also immobilized on a mesoporous support (SBA15) followed by the generation of size-controlled Pd nanoparticles (diameter μ2-6 nm, as based on HR-TEM), leading to an effective heterogeneous hydrogenation catalyst for the transformation of various arenes to saturated carbocycles.
Uniformly sized Pt nanoparticles dispersed at high loading on Titania nanotubes
Chávez, C. Angeles,Cortés-Jácome, M. A.,Encarnación-Gómez, C.,García, J. R. Vargas,Hernández-Cortéz, J. G.,Hernández-Cruz, M. G.,López, I. Cuauhtémoc,Medina-Mendoza, A. K.,Salinas, E. López,Toledo-Antonio, J. A.
, (2020/06/01)
A range of Pt loadings (0.9–21.5 wt. %) on titania nanotubes (TNT) catalysts were prepared with a view to address metal-support interaction effects on Pt nanoparticles (size, dispersion, shape) and were prepared by a vapor-phase impregnation method using Pt(acac). The reduced catalysts were characterized by XRD, TEM, H2-TPD, CO adsorption FTIR and examined as catalysts in naphthalene hydrogenation. Pt nanoparticles have a very uniform size between 1.4–2.2 nm for Pt loadings 0.9–21.5 wt% as indicated by TEM, H2-TPD and CO-adsorption FTIR. A strong metal-support interaction between Pt and TNT support hinder Pt nanoparticles to agglomerate into larger particles, even at high Pt loadings. Both Pt edge sites and exposed surface total Pt sites are highest at 10.2 wt.% Pt loading and parallels naphthalene hydrogenation activity which peaks at this loading.
Facile in situ Encapsulation of Highly Dispersed Ni@MCM-41 for the Trans-Decalin Production from Hydrogenation of Naphthalene at Low Temperature
Song, Xiaoyun,Guan, Qingxin,Shu, Yu,Zhang, Xiaojing,Li, Wei
, p. 1286 - 1294 (2019/01/25)
Ni@MCM-41 catalyst that has uniformly distributed, highly dispersed Ni nanoparticles (about 2.3 nm) was designed and successfully synthesized by in situ encapsulation of Ni in the channels of MCM-41. This catalyst exhibits excellent thermal stability and hydrogenation activity. Water insoluble nickel acetylacetonate (Ni(acac)2) was first dissolved aqueous solution of cetyltrimethyl ammonium bromide (CTAB) and encapsulated in micelles of CTAB. Sodium silicate was used as a silicon source to rapidly hydrolyze and then wrap on the micelle surface to synthesize the MCM-41 zeolite. The MCM-41 zeolite encapsulating Ni(acac)2 was synthesized within a short time (4 h) at 120 °C. Compared with conventional supported catalysts, thus 3 wt.% Ni@MCM-41 has ultra-small uniformly distributed Ni nanoparticles and exhibits improved activity for the hydrogenation of naphthalene to decalin at very low reaction temperatures. The TOF and the apparent activation energy of Ni@MCM-41 and the conventional catalysts (Ni/MCM-41 and Pt/MCM-41) were evaluated and compared. And the catalysis mechanism was analyzed. Furthermore, this Ni@MCM-41 catalyst offers an additional advantage of selectivity in decalin isomerization; 92 % trans-decalin selectivity was achieved at a wide temperature range.
Synthesis of hierarchical zeolites by solid state crystallization of aluminosilicate nanogels
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Page/Page column 9; 10; 15, (2019/07/19)
Hierarchically porous ZSM-5 zeolites, having macropores, mesopores, and micropores are formed using a solid-state crystallization process. An aluminosilicate nanogel prepared with precursors, solvent, and a structure-directing agent is provided. The solvent is evaporated from the aluminosilicate nanogel at room temperature. The dried aluminosilicate nanogel is then heated to promote crystallization. The crystallized zeolites are calcined to remove the structure-directing agent.
Properties of Nanosized Cobalt-Molybdenum Sulfide Catalyst Formed In Situ from Sulfonium Thiosalt
Knyazeva,Panyukova,Maximov
, p. 504 - 510 (2019/06/19)
Abstract: A cobalt-molybdenum-containing sulfonium thiosalt is prepared; when decomposed in situ, it forms the catalyst active in hydrogenation and hydrodesulfurization. The possibility of catalyst isolation and reuse in several hydrogenation cycles is shown. It is found that a lower selectivity for naphthalene hydrogenation products in catalyst recycling is associated with decrease in the dispersity of molybdenum sulfide nanoparticles and reduction in the degree of their promotion by cobalt atoms.
Simultaneous Desulfurization and Hydrogenation of Model Diesel Fuel over Ni/ZnO–PdPt/USY Hybrid Catalyst
Lichun Huang,Du, Mingxian,Wang, Weixing,Tang, Mingxing,Ge, Hui
, p. 2148 - 2153 (2018/10/24)
Abstract: The clean production requires deep desulfurization to meet stringent environmental specification and aromatics hydrogenation to improve the quality of transport fuels. To achieve this objective, hybrid catalyst was prepared by mixing of PdPt/USY with Ni/ZnO powders. It was found that the hybrid showed higher activity and stability to hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrogenation of tetralin than Ni/ZnO or PtPd/USY counterparts. PdPt/USY containing catalysts exhibited high trans/cis ration of decalin, this can be attributed to the isomerization on the acid sites of USY and the reduced interaction between olefinic intermediates with PdPt bimetals. The hybrid catalyst also had high hydrogenation ability and stability to bulky aromatics of pyrene with the existence of DBT. The XRD, XPS, and BET characterizations revealed that PdPt/USY is responsible for DBT HDS, HYD and isomerization whereas Ni/ZnO play supporting role as sulfur adsorbent in hybrid catalyst. Hydrogen spillover between Ni/ZnO and PdPt/USY components facilitates the aromatic hydrogenation and DBT HDS. This study proposed that the PdPt/USY–Ni/ZnO hybrid catalyst may be an alternative in the hydrotreatment of diesel fuel.
Polysilane-Immobilized Rh-Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism
Miyamura, Hiroyuki,Suzuki, Aya,Yasukawa, Tomohiro,Kobayashi, Shu
supporting information, p. 11325 - 11334 (2018/09/06)
Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.
