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.
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.
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.
