F:Flammable;
110-82-7Relevant articles and documents
Structural characterization and catalytic activity of the rhodium-carbene complex Rh(PPh3)2(IMes)Cl (IMes = bis(1,3-(2,4,6-trimethylphenyl)imidazol-2-ylidene)
Grasa, Gabriela A.,Moore, Zakhia,Martin, Kenneth L.,Stevens, Edwin D.,Nolan, Steven P.,Paquet, Valérie,Lebel, Hélène
, p. 126 - 131 (2002)
The rhodium-carbene complex Rh(PPh3)2(IMes)Cl (2) is an active catalyst for the hydroboration of simple olefins at room temperature. The reactivity of 2 was also tested in the methylenation of aldehydes. The crystal structure of 2 is
Subtle factors are important: Radical formation and transmetallation in reactions of butyl cuprates with cyclohexyl iodide
Bertz, Steven H.,Human, Jason,Ogle, Craig A.,Seagle, Paul
, p. 392 - 394 (2005)
The reactions of Bu2CuLi·LiI and Bu2CuLi LiCN with cyclohexyl iodide are critically dependent upon subtle factors such as the surface properties of the reaction vessel, nature of the solvent still and lot of 'ultrapure' copper salt i
Effect of hydrohalogenation of metal/zeolite catalysts for cyclohexene hydroconversion -Part 3- Pd/H-ZSM-5 catalysts
Aboul-Gheit, Noha A. K.
, p. 1211 - 1222 (2007)
Cyclohexene (CHE) hydroconversion was performed in a flow reactor at atmospheric pressure and temperatures of 50-400 °C using: Pd/H-ZSM-5, Pd/H-ZSM-5(HCl), and Pd/H-ZSM-5(HF) catalysts. These catalysts were characterized for acid site strength distribution via NH3 TPD, Pd dispersion via H2 chemisorption, TPR via reduction of the metal oxide in the catalysts and XRD for tracing crystallinity. The hydroconversion steps proceeded as follows: CHE → Cyclohexane (CHA); CHE → Methylcyclopentenes (MCPEs) → Methylcyclopentane (MCPA); CHE → Cyclohexadienes (CHDEs) → Benzene → Alkylbenzenes; CHE and others → Hydrocracked products. The overall hydroconversion of CHE was achieved in the catalyst order: Pd/H-ZSM-5 > Pd/H-ZSM-5(HF) > Pd/H-ZSM-5(HCl). CHE hydrogenation step was the major reaction at low temperatures which significantly inhibited via HCl treatment, but slightly enhanced via HF treatment. At medium temperatures, on all catalysts, isomerisation to MCPEs and MCPA increase to a maximum then a decline with a further increase of temperature. The overall isomerisation of CHE was highest on the untreated catalyst. During the higher temperature range, dehydrogenation, alkylation and hydrocracking were increased with temperature. Dehydrogenation of CHE always yielded larger amounts of 1,3-CHDE than 1,4-CHDE. These cyclohexadienes were produced in the catalyst order: Pd/H-ZSM-5(HF) > Pd/H-ZSM-5(HCl) > Pd/H-ZSM-5. In general, benzene alkylation to toluene exceeded that of xylenes, indicating that the second methylation is more difficult than the first. However, the catalytic activities for benzene and toluene production were in the order: Pd/H-ZSM-5 ? Pd/H-ZSM-5(HCl) > Pd/H-ZSM-5(HF), whereas for xylenes production, Pd/H-ZSM-5 ? Pd/H-ZSM-5(HF) > Pd/H-ZSM-5(HCl). Intrapore diffusion plays an important role during the dehydrogenation reactions as well as during the interconversion of individual aromatic hydrocarbons.
Doping effects of B in ZrO2 on structural and catalytic properties of Ru/B-ZrO2 catalysts for benzene partial hydrogenation
Zhou, Gongbing,Pei, Yan,Jiang, Zheng,Fan, Kangnian,Qiao, Minghua,Sun, Bin,Zong, Baoning
, p. 393 - 403 (2014)
The B-doped ZrO2 (B-ZrO2) samples with different B/Zr ratios were synthesized using zirconium oxychloride and boric acid as the precursors. Their crystallographic phase retained as tetragonal ZrO2 after the doping of B; however, the amount of the Lewis acid sites increased from 46.1 μmolNH3 g-1 on ZrO2 to 100.6 μmolNH3 g-1 on B-ZrO2(1/10) with the nominal B/Zr molar ratio of 1/10. The Ru/B-ZrO2 catalysts were then prepared by chemical reduction, and their electronic and structural properties were systematically characterized by spectroscopic techniques. It is identified that the Ru nanoparticles (NPs) supported on these B-ZrO2 samples exhibited similar size, chemical state, and microstructure. In the partial hydrogenation of benzene, the turnover frequency of benzene was linearly proportional to the amount of the acid sites on the supports, whereas the selectivity toward cyclohexene displayed a volcanic evolution passing through a maximum of 88% on the Ru/B-ZrO2(1/15) catalyst. Kinetic analysis indicated that the acid sites improved the rate constants of the benzene to cyclohexene step (k1) and the cyclohexene to cyclohexane step (k 2) to different degrees. The resulting k1/k2 ratio increased from 3.7 × 10-2 l mol-1 (Ru/ZrO 2) to 4.8 × 10-2 l mol-1 (Ru/B-ZrO 2(1/15)), and then declined to 4.1 × 10-2 l mol -1 (Ru/B-ZrO2(1/10)), which explained the volcanic evolution of the selectivity toward cyclohexene with respect to the acid amount.
Surface engineering on a nanocatalyst: basic zinc salt nanoclusters improve catalytic performances of Ru nanoparticles
Peng, Zhikun,Liu, Xu,Lin, Huinan,Wang, Zhuo,Li, Zhongjun,Li, Baojun,Liu, Zhongyi,Liu, Shouchang
, p. 17694 - 17703 (2016)
Herein, we report novel surface-modified Ru-based catalysts by the chemisorption of basic zinc sulfate salts (3Zn(OH)2·ZnSO4·xH2O, BZSSs) and demonstrate their enhanced selectivity toward cyclohexene (CHE) in benzene-selective hydrogenation. BZSS nanoclusters are confirmed to regulate the surface and electronic properties of Ru nanoparticles. The surface active sites on Ru nanoparticles are reconstructed because the strong active sites are selectively occupied and blocked by BZSS nanoclusters. Lewis acid active sites, which are introduced by the BZSS and modified by the interaction between Ru(0) and the BZSS, can retain the activity of the Ru catalyst and greatly improve the selectivity toward CHE. Benefiting from the BZSS nanoclusters located on the Ru nanoparticles, the surface-modified catalysts present excellent selectivity with high activity for the hydrogenation reaction. This is particularly clear in that the catalyst operated stably for more than 600 h on an industrial production line; the benzene conversion was maintained at 40%, and the selectivity toward CHE was maintained over 80%.
Effect of the thermal treatment temperature of RuNi bimetallic nanocatalysts on their catalytic performance for benzene hydrogenation
Zhu, Lihua,Zheng, Jinbao,Yu, Changlin,Zhang, Nuowei,Shu, Qing,Zhou, Hua,Li, Yunhua,Chen, Bing H.
, p. 13110 - 13119 (2016)
The thermal treatment temperature of bimetallic nanocatalysts plays an important role in determining their catalytic performance. In this study, the synthesis of RuNi bimetallic nanoparticles (BNPs) supported on carbon black catalysts (denoted as RuNi BNS
Disproportionation of cyclohexadienes and cyclohexene under the action of catalysts based on supported tetranuclear potassium carbonylruthenate K2[Ru4(CO)13]
Yunusov,Rummel,Kalyuzhnaya,Shur
, p. 843 - 847 (2014)
The deposition of tetranuclear potassium carbonylruthenate K2[Ru4(CO)13] onto carbon Sibunit, SiO2, γ-Al2O3, and MgO followed by the thermal decomposition of the supported anionic cluster at 300°C in an H2 or Ar flow leads to systems capable of catalyzing the disproportionation of cyclohexa-1,3-diene and cyclohexa-1,4-diene. The reactions proceed at room temperature to form mixtures of benzene and cyclohexene, benzene, cyclohexene, and cyclohexane, or benzene and cyclohexane. The catalytic systems developed are also active in cyclohexene disproportionation to benzene and cyclohexane at 100-130 °C.
Bimolecular Hydrogen Transfer over Zeolites and SAPOs having the Faujasite Structure
Dwyer, John,Karim, Khalid,Ojo, Adeola F.
, p. 783 - 786 (1991)
Silica-rich Y zeolites prepared by primary or secondary synthesis and samples of SAPO-37 have been synthesized and characterized.These materials are then evaluated as catalysts for the transformation of cyclohexene.From product distribution at low conversion the relative rates of isomerization and bimolecular hydrogen tranfer are measured and discussed in terms of active site density.
HYDROGENATION OF CYCLOHEXENE ON DIFFERENT TYPES OF CATALYSTS
Kharlamov, V. V.,Garanin, V. I.,Karakhotin, S. N.,Minachev, Kh. M.
, p. 612 - 618 (1992)
Hydrogenation of cyclohexene has been studied under pressure in a flow reactor on the following catalysts: Na- and H-forms of Y-type zeolites, erionite, magnesium and lanthanum oxides, palladium on silica and aluminum oxide.This reaction is accompanied by skeletal isomerization to give methylcyclopentane and methylcyclopentenes.The differences in activation energies for isomerization and hydrogenation reactions were estimated as 83-96 kJ/mole for NaY and Na,K-erionite, 33-50 kJ/mole for the H-forms of the zeolites, 33-37 kJ/mole on the Pd catalysts, and 25-33 kJ/mole on magnesium and lanthanum oxides.It is suggested that the cyclohexyl complex, formed as an intermediate during hydrogenation of cyclohexene on Na-forms of the zeolites, is neither a carbocation nor a radical. Keywords: cyclohexene, zeolites, hydrogenation.
Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts
Wang, Hongliang,Wang, Huamin,Kuhn, Eric,Tucker, Melvin P.,Yang, Bin
, p. 285 - 291 (2018)
Super Lewis acids containing the triflate anion [e.g., Hf(OTf)4, Ln(OTf)3, In(OTf)3, Al(OTf)3] and noble metal catalysts (e.g., Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote deoxygenation reactions catalyzed by super Lewis acids.
