- Dissociation Dynamics of Energy-Selected C5H10(1+) Ions
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The fragmentation reactions of six C5H10(1+) isomers loosing CH3 and C2H4 have been investigated by using the photoelectron photoion coincidence (PEPICO) technique.Except for the 2-methyl-2-butene ion dissociation all precursors exhibit a two-component decay indicating that dissociation occurs from at least two distinct forms of molecular ions.The observation is rationalized in terms of competition between dissociation from the original ion structure and isomerization to a lower energy isomer subsequently decomposing at a slower rate.The latter isomer is identified as the 2-methyl-2-butene molecular ion.The comparison of the measured absolute rates with those predicted by the statistical theory (RRKM/QET) suggests that the transition-state switching model is necessary for a quantitative agreement.
- Brand, Willi A.,Baer, Tomas
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Read Online
- Fabricating nickel phyllosilicate-like nanosheets to prepare a defect-rich catalyst for the one-pot conversion of lignin into hydrocarbons under mild conditions
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The one-pot conversion of lignin biomass into high-grade hydrocarbon biofuels via catalytic hydrodeoxygenation (HDO) holds significant promise for renewable energy. A great challenge for this route involves developing efficient non-noble metal catalysts to obtain a high yield of hydrocarbons under relatively mild conditions. Herein, a high-performance catalyst has been prepared via the in situ reduction of Ni phyllosilicate-like nanosheets (Ni-PS) synthesized by a reduction-oxidation strategy at room temperature. The Ni-PS precursors are partly converted into Ni0 nanoparticles by in situ reduction and the rest remain as supports. The Si-containing supports are found to have strong interactions with the nickel species, hindering the aggregation of Ni0 particles and minimizing the Ni0 particle size. The catalyst contains abundant surface defects, weak Lewis acid sites and highly dispersed Ni0 particles. The catalyst exhibits excellent catalytic activity towards the depolymerization and HDO of the lignin model compound, 2-phenylethyl phenyl ether (PPE), and the enzymatic hydrolysis of lignin under mild conditions, with 98.3% cycloalkane yield for the HDO of PPE under 3 MPa H2 pressure at 160 °C and 40.4% hydrocarbon yield for that of lignin under 3 MPa H2 pressure at 240 °C, and its catalytic activity can compete with reported noble metal catalysts.
- Cao, Meifang,Chen, Bo,He, Chengzhi,Ouyang, Xinping,Qian, Yong,Qiu, Xueqing
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supporting information
p. 846 - 857
(2022/02/09)
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- Improved Hydrodeoxygenation of Phenol to Cyclohexane on NiFe Alloy Catalysts Derived from Phyllosilicates
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A phyllosilicate-derived NiFe/SiO2 catalyst (NiFe/SiO2?AE) was successfully prepared by the ammonia evaporation method and applied in the hydrodeoxygenation of phenol to cyclohexane. Another two catalysts were also prepared for a comparison by impregnation (NiFe/SiO2?IM) and deposition-precipitation (NiFe/SiO2?DP) methods, respectively. It was found that Ni?Fe alloy, the active sites for the hydrogenolysis of C?O bond, can be obtained by the reduction of NiFe2O4 (IM) or phyllosilicate (DP and AE) by H2. The AE strategy can generate more phyllosilicate structure, which improves the dispersion of both Ni?Fe alloy and metallic Ni sites and allows the formation of more interface between these two kinds of sites as well. Therefore, the NiFe/SiO2?AE exhibits a significantly high catalytic performance in the HDO of phenol to cyclohexane. Moreover, the turnover frequency of Ni?Fe alloy sites over NiFe/SiO2?AE catalysts is much higher than those of other two catalysts. It is suggested that the enhanced synergy between the two kinds of active sites in the adsorption of C?O groups and hydrogen molecules ensures the superior intrinsic activity in HDO process.
- Han, Qiao,Wang, Hui,Rehman, Mooeez Ur,Shang, Xin,Chen, Haijun,Ji, Na,Tong, Xinli,Shi, Hui,Zhao, Yujun
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supporting information
p. 5069 - 5076
(2021/12/14)
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- Visible-Light-Enhanced Cobalt-Catalyzed Hydrogenation: Switchable Catalysis Enabled by Divergence between Thermal and Photochemical Pathways
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The catalytic hydrogenation activity of the readily prepared, coordinatively saturated cobalt(I) precatalyst, (R,R)-(iPrDuPhos)Co(CO)2H ((R,R)-iPrDuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene), is described. While efficient turnover was observed with a range of alkenes upon heating to 100 °C, the catalytic performance of the cobalt catalyst was markedly enhanced upon irradiation with blue light at 35 °C. This improved reactivity enabled hydrogenation of terminal, di-, and trisubstituted alkenes, alkynes, and carbonyl compounds. A combination of deuterium labeling studies, hydrogenation of alkenes containing radical clocks, and experiments probing relative rates supports a hydrogen atom transfer pathway under thermal conditions that is enabled by a relatively weak cobalt-hydrogen bond of 54 kcal/mol. In contrast, data for the photocatalytic reactions support light-induced dissociation of a carbonyl ligand followed by a coordination-insertion sequence where the product is released by combination of a cobalt alkyl intermediate with the starting hydride, (R,R)-(iPrDuPhos)Co(CO)2H. These results demonstrate the versatility of catalysis with Earth-abundant metals as pathways involving open-versus closed-shell intermediates can be switched by the energy source.
- Mendelsohn, Lauren N.,MacNeil, Connor S.,Tian, Lei,Park, Yoonsu,Scholes, Gregory D.,Chirik, Paul J.
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p. 1351 - 1360
(2021/02/01)
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- Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
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A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
- Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
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supporting information
p. 18591 - 18598
(2021/06/28)
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- Fe Exchanged Supported Phosphomolybdic Acid: Synthesis, Characterization and Low Temperature Water Mediated Hydrogenation of Cyclohexene
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In this article, first time we are reporting two steps synthesis of Fe exchanged phosphomolybdic acid supported on zirconia (Fe-PMA/ZrO2) by incipient wet impregnation and ion exchange method. The obtained material was well characterized by EDX mapping, ICP, FT-IR, Raman, 31P MAS NMR, ESR, XPS and powder XRD. The catalytic evaluation was explored for cyclohexene hydrogenation at low temperature using water as a solvent. The obtained results demonstrate remarkable efficiency of the synthesized material as a sustainable heterogeneous catalyst with very low amount of active species (Fe: 0.024?mol%), 90% conversion, high substrate/catalyst ratio (4157/1) as well as TON (3742) for 3 catalytic cycles. The present synthetic approach is highly green as it does not involve use of any noble metal, with no waste generation (E-factor = 0) as well as high reaction mass efficiency (92.20%). Graphical Abstract: [Figure not available: see fulltext.]
- Patel, Anjali,Patel, Jay
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- Mechanistic Study on Deoxydehydration and Hydrogenation of Methyl Glycosides to Dideoxy Sugars over a ReO x-Pd/CeO2Catalyst
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We found that nonprotected methyl glycosides with cis-vicinal OH groups could be converted to the corresponding methyl dideoxy glycosides by deoxydehydration and consecutive hydrogenation (DODH + HG) over a ReOx-Pd/CeO2 catalyst with gaseous H2. In the study, the reactivity of the methyl glycosides in DODH was clearly lower than that of simple cyclic vicinal diols, such as cis-1,2-cyclohexanediol and cis-1,2-cyclopentanediol, and the reactivity of the methyl glycosides was also different. Herein, we investigated the reactivity difference based on kinetic studies and density-functional theory (DFT) calculations. The kinetic studies suggest that the reactivity difference between the methyl glycosides and the simple diols is derived from the OH group of methyl glycosides except the cis-vicinal diols, and that the reactivity difference among the methyl glycosides will be associated with the configuration of the substituents adjacent to the cis-vicinal diols, while the reaction mechanism of DODH is suggested to be basically similar judging from almost the same reaction orders with respect to the substrate concentration and H2 pressure in all substrates. The adsorption and transition states of methyl α -l- rhamnopyranoside and methyl α-l-fucopyranoside, which have a large reactivity difference (methyl α-l-rhamnopyranoside? methyl α-l-fucopyranoside), were estimated by DFT calculations with ReOx/CeO2 as the active site of the ReOx-Pd/CeO2 catalyst, showing that the main difference is the activation energy in DODH of these substrates (65 kJ mol-1 for methyl α-l-rhamnopyranoside and 77 kJ mol-1 for methyl α-l-fucopyranoside), which was also supported by the results of Arrhenius plots (63 and 73 kJ mol-1 for methyl α-l-rhamnopyranoside and methyl α-l-fucopyranoside, respectively). The activation energy was influenced by the torsional angle of the substituents adjacent to the cis-vicinal OH groups, which is derived from the interaction of the OH group adjacent to the cis-vicinal OH groups and the surface hydroxy groups on CeO2.
- Cao, Ji,Hasegawa, Jun-Ya,Hosaka, Ryu,Nakagawa, Yoshinao,Nakayama, Akira,Tamura, Masazumi,Tomishige, Keiichi
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p. 12040 - 12051
(2020/11/27)
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- GROUP 1 METAL ION CONTENT OF MICROPOROUS MOLECULAR SIEVE CATALYSTS
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A catalyst comprising a microporous crystalline aluminosilicate having a Constraint Index less than or equal to 12, a Group 1 alkali metal or a compound thereof and/or a Group 2 alkaline earth metal or a compound thereof, a Group 10 metal or a compound thereof, and optionally a Group 11 metal or a compound thereof; wherein the total amount of Group 1 and/or Group 2 metal is present at a ratio that is optimized for the desirable chemical conversion process.
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Paragraph 0046-0047
(2020/05/28)
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- Preparation of Highly Active Monometallic Rhenium Catalysts for Selective Synthesis of 1,4-Butanediol from 1,4-Anhydroerythritol
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1,4-Butanediol can be produced from 1,4-anhydroerythritol through the co-catalysis of monometallic mixed catalysts (ReOx/CeO2+ReOx/C) in the one-pot reduction with H2. The highest yield of 1,4-butanediol was over 80 %, which is similar to the value obtained over ReOx–Au/CeO2+ReOx/C catalysts. Mixed catalysts of CeO2+ReOx/C showed almost the same performance, giving 89 % yield of 1,4-butanediol. The reactivity trends of possible intermediates suggest that the reaction mechanism over ReOx/CeO2+ReOx/C is similar to that over ReOx–Au/CeO2+ReOx/C: deoxydehydration (DODH) of 1,4-anhydroerythritol to 2,5-dihydrofuran over ReOx species on the CeO2 support with the promotion of H2 activation by ReOx/C, isomerization of 2,5-dihydrofuran to 2,3-dihydrofuran catalyzed by ReOx on the C support, hydration of 2,3-dihydrofuran catalyzed by C, and hydrogenation to 1,4-butanediol catalyzed by ReOx/C. The reaction order of conversion of 1,4-anhydroerythritol with respect to H2 pressure is almost zero and this indicates that the rate-determining step is the formation of 2,5-dihydrofuran from the coordinated substrate with reduced Re in the DODH step. The activity of ReOx/CeO2+ReOx/C is higher than that of ReOx–Au/CeO2+ReOx/C, which is probably related to the reducibility of ReOx/C and the mobility of the Re species between the supports. High-valent Re species such as Re7+ on the CeO2 and C supports are mobile in the solvent; however, low-valent Re species, including metallic Re species, have much lower mobility. Metallic Re and cationic low-valent Re species with high reducibility and low mobility can be present on the carbon support as a trigger for H2 activation and promoter of the reduction of Re species on CeO2. The presence of noble metals such as Au can enhance the reducibility through the activation of H2 molecules on the noble metal and the formation of spilt-over hydrogen over noble metal/CeO2, as indicated by H2 temperature-programmed reduction. The higher reducibility of ReOx–Au/CeO2 lowers the DODH activity of ReOx–Au/CeO2+ReOx/C in comparison with ReOx/CeO2+ReOx/C by restricting the movement of Re species from C to CeO2.
- Wang, Tianmiao,Tamura, Masazumi,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 3615 - 3626
(2019/07/15)
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- Mononuclear iron complex and organic synthesis reaction using same
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A mononuclear iron bivalent complex having iron-silicon bonds, which is represented by formula (1), can exhibit an excellent catalytic activity in at least one reaction selected from three reactions, i.e., a hydrosilylation reaction, a hydrogenation reaction and a reaction for reducing a carbonyl compound. (In the formula, R1 to R6 independently represent a hydrogen atom, an alkyl group which may be substituted by X, or the like; X represents a halogen atom, or the like; L1 represents at least one two-electron ligand selected from an isonitrile ligand, an amine ligand, an imine ligand, a nitrogenated heterocyclic ring, a phosphine ligand, a phosphite ligand and a sulfide ligand, wherein, when multiple L1's are present, two L1's may be bonded to each other; L2 represents a two-electron ligand that is different from a CO ligand or the above-mentioned L1, wherein, when multiple L2's are present, two L2's may be bonded to each other; and m1 represents an integer of 1 to 4 and m2 represents an integer of 0 to 3, wherein the sum total of m1 and m2 (i.e., m1+m2) satisfies 3 or 4.)
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Page/Page column 30; 31; 34
(2019/08/20)
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- Highly selective and recyclable hydrogenation of α-pinene catalyzed by ruthenium nanoparticles loaded on amphiphilic core–shell magnetic nanomaterials
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A multifunctional nanomaterial (Fe3O4@SiO2@CX@NH2) comprising a magnetic core, a silicon protective interlayer, and an amphiphilic silica shell is successfully prepared. Ru nanoparticles catalyst loaded on Fe3O4@SiO2@CX@NH2 is used in hydrogenation of α-pinene for the first time. The novel nanomaterial with amphipathy can be used as a solid foaming agent to increase gas–liquid–solid three-phase contact and accelerate the reaction. Under the mild conditions (40?°C, 1?MPa H2, 3?h), 99.9% α-pinene conversion and 98.9% cis-pinane selectivity are obtained, which is by far the best results reported. Furthermore, the magnetic nanocomposite catalyst can be easily separated by an external magnet and reused nine times with high selectivity maintaining.
- Wu, Fang-Zhu,Yu, Feng-Li,Yuan, Bing,Xie, Cong-Xia,Yu, Shi-Tao
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- Synthetic method for high-density liquid hydrocarbon fuel with density larger than 1 g/cm3
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The invention provides a synthetic method for a high-density liquid hydrocarbon fuel with a density larger than 1 g/cm3. The synthetic method comprises: a Diels-Alder addition reaction with a raw material of cyclopentadiene, a reaction temperature of 170 DEG C to 185 DEG C and reaction time of 6 to 24 hours; a catalytic hydrogenation reduction reaction with addition of a hydrogenation catalyst, ahydrogen pressure of 2 MPa to 5 MPa, a reaction temperature of 150 DEG C to 220 DEG C and reaction time of 8 to 24 hours; and a molecular structure isomerization reaction with addition of a solvent and an AlCl3 catalyst into a material obtained from the process of the catalytic hydrogenation reduction reaction, and with a reaction temperature of 25 DEG C to 70 DEG C and reaction time of 12 to 24 hours. According to the invention, no catalyst is needed to be used in the Diels-Alder addition reaction; meanwhile, through adjustment of the reaction time and the reaction temperature of Diels-Alder,the component constitution proportion of the high-density liquid hydrocarbon fuel can be adjusted. The synthetic method provided by the invention has the advantages of simple process route, low preparation cost, and facilitation of scale production.
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Paragraph 0012-0016
(2018/04/26)
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- Sodium borohydride-nickel chloride hexahydrate in EtOH/PEG-400 as an efficient and recyclable catalytic system for the reduction of alkenes
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An efficient, safe and one-pot convenient catalytic system has been developed for the reduction of alkenes using NaBH4-NiCl2·6H2O in EtOH/PEG-400 under mild conditions. In this catalytic system, a variety of alkenes (including trisubstituted alkene α-pinene) were well reduced and the Ni catalyst could be recycled.
- Li, Kaoxue,Liu, Chuanchao,Wang, Kang,Ren, Yang,Li, Fahui
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p. 7761 - 7764
(2018/03/01)
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- Vapor-Phase Hydrodeoxygenation of Guaiacol to Aromatics over Pt/HBeta: Identification of the Role of Acid Sites and Metal Sites on the Reaction Pathway
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A comparative study of the hydrodeoxygenation of guaiacol, a phenolic compound derived from the lignin fraction of biomass with both hydroxyl and methoxyl functional groups, was performed on HBeta, Pt/SiO2, and Pt/HBeta at 350 °C and atmospheric pressure. The reaction pathway and the roles of the acid and metal sites were studied. Acid sites catalyze transalkylation and dehydroxylation reactions to produce monohydroxyl phenolics (phenol, cresols, and xylenols) as the major final products. Pt sites catalyze demethylation to result in catechol as the primary product, which can either be deoxygenated to phenol followed by phenol to benzene, or decarbonylated to cyclopentanone and further to butane. The close proximity of Pt and acid sites in bifunctional Pt/HBeta improves transalkylation and deoxygenation (or dehydroxylation) reactions and inhibits demethylation and decarbonylation reactions significantly, which leads to aromatics as the major final products with a total yield >85 %. Both the activity and stability of bifunctional Pt/HBeta during the hydrodeoxygenation of guaiacol are improved compared to those of HBeta and Pt/SiO2. The addition of water to the feed further improves the activity and stability through the hydrolysis of the O?CH3 bond of guaiacol on acid sites and the removal of coke around Pt.
- Nie, Lei,Peng, Bo,Zhu, Xinli
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p. 1064 - 1074
(2018/02/09)
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- Divalent Silicon-Assisted Activation of Dihydrogen in a Bis(N-heterocyclic silylene)xanthene Nickel(0) Complex for Efficient Catalytic Hydrogenation of Olefins
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The first chelating bis(N-heterocyclic silylene)xanthene ligand [SiII(Xant)SiII] as well as its Ni complexes [SiII(Xant)SiII]Ni(η2-1,3-cod) and [SiII(Xant)SiII]Ni(PMe3)2 were synthesized and fully characterized. Exposing [SiII(Xant)SiII]Ni(η2-1,3-cod) to 1 bar H2 at room temperature quantitatively generated an unexpected dinuclear hydrido Ni complex with a four-membered planar Ni2Si2 core. Exchange of the 1,3-COD ligand by PMe3 led to [SiII(Xant)SiII]Ni(PMe3)2, which could activate H2 reversibly to afford the first SiII-stabilized mononuclear dihydrido Ni complex characterized by multinuclear NMR and single-crystal X-ray diffraction analysis. [SiII(Xant)SiII]Ni(η2-1,3-cod) is a strikingly efficient precatalyst for homogeneous hydrogenation of olefins with a wide substrate scope under 1 bar H2 pressure at room temperature. DFT calculations reveal a novel mode of H2 activation, in which the SiII atoms of the [SiII(Xant)SiII] ligand are involved in the key step of H2 cleavage and hydrogen transfer to the olefin.
- Wang, Yuwen,Kostenko, Arseni,Yao, Shenglai,Driess, Matthias
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supporting information
p. 13499 - 13506
(2017/10/05)
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- Hydrodeoxygenation of guaiacol on tungstated zirconia supported Ru catalysts
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Ru nanoparticles supported on tungstated zirconia (WZr) were prepared and used for the catalytic hydrodeoxygenation of guaiacol to deoxygenated hydrocarbon fuels. The tuning of tungsten, from 5 to 20?wt%, adjusted the number of acid sites on the tungstated zirconia and the size of the Ru nanoparticles. The optimum fraction of tungsten was determined for the optimum hydrodeoxygenation activity. The conversion of guaiacol reached a maximum of 96.8% for 10?wt% of tungsten. Increasing the tungsten fraction increased the number of acid sites and the dispersion of Ru, but the formation of tungsten oxide (WOx) particles with too large fraction of tungsten inhibited the formation of smaller Ru nanoparticles, thus reducing the catalytic activity.
- Dwiatmoko, Adid Adep,Kim, Inho,Zhou, Lipeng,Choi, Jae-Wook,Suh, Dong Jin,Jae, Jungho,Ha, Jeong-Myeong
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- Performance, Structure, and Mechanism of ReOx-Pd/CeO2 Catalyst for Simultaneous Removal of Vicinal OH Groups with H2
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The ceria-supported rhenium catalyst modified with palladium (ReOx-Pd/CeO2 (Re = 2 wt %, Pd/Re = 0.25)) is still the best catalyst for simultaneous hydrodeoxygenation. Higher Re loading amount decreased the activity. The simultaneous hydrodeoxygenation of cyclic vicinal diols occurs with high cis-stereoselectivity. ReOx-Pd/CeO2 catalysts were characterized by means of XRD, TEM, H2-TPR, XAFS, XPS, Raman, and DFT calculations. The Re species on ReOx-Pd/CeO2 (Re = 2 wt %, Pd/Re = 0.25) catalyst after reduction and after stoichiometric reaction of 1,2-hexanediol to 1-hexene were ReIV and ReVI, and the ReIV species were converted to ReVI through the stoichiometric reaction. The Re species on ReOx-Pd/CeO2 are proposed to be randomly located on the CeO2 surface, and probably only monomeric Re species have catalytic activity for simultaneous hydrodeoxygenation. This model can explain the higher activity of Re = 2 wt % catalyst than those of higher Re loading catalysts. The reaction is proposed to proceed by the tetra/hexavalent redox cycle of the Re center in the catalysis followed by hydrogenation.
- Ota, Nobuhiko,Tamura, Masazumi,Nakagawa, Yoshinao,Okumura, Kazu,Tomishige, Keiichi
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p. 3213 - 3226
(2016/07/06)
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- Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor
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There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C-C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric acid is the sole byproduct. Mechanistic experiments suggest that this reaction is made possible by a hydrogen atom transfer from water that generates a Pd-hydride intermediate. Importantly, complete deuterium incorporation from stoichiometric D2O has also been achieved.
- Cummings, Steven P.,Le, Thanh-Ngoc,Fernandez, Gilberto E.,Quiambao, Lorenzo G.,Stokes, Benjamin J.
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supporting information
p. 6107 - 6110
(2016/06/09)
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- Dehydrocyclization of C6 Hydrocarbon with and Without Oxygen Containing Substituent over Pt/(Na)-Al2O3 Catalyst
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The presence of hydroxyl or keto functional group affects both activity and selectivity for dehydrocyclization of C6 hydrocarbon over Pt/(Na)-Al2O3 catalyst. Under similar reaction conditions, n-hexane produces benzene as the primary product (>40 %), whereas dehydration is a major reaction pathway for 2-hexanol and yields mainly hexenes (>70 %). However, 2-hexanone was found to be involved in a variety of reactions over Pt/(Na)-Al2O3 catalyst and produces lower hydrocarbons (C2-C5), 5-dodecanone, 2- And 5-nonanones, and 2-acetyl-3-propyl-2-cyclohexen-1-one. The presence of hydroxyl (-OH) or keto group (=C=O) at the C-2 position alters the interaction of C6 hydrocarbon with the catalyst surface which eventually controls the overall product selectivity.
- Gnanamani, Muthu Kumaran,Shafer, Wilson D.,Keogh, Robert A.,Davis, Burtron H.
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p. 424 - 432
(2016/02/23)
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- Phosphidoboratabenzene-rhodium(i) complexes as precatalysts for the hydrogenation of alkenes at room temperature and atmospheric pressure
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The di-tert-butylphosphido-boratabenzene ligand (DTBB) reacts with [(C2H4)2RhCl]2 yielding the dimeric species [(C2H4)Rh(DTBB)]2 (1). This species was fully characterized by multinuclear NMR and X-ray crystallography. Complex 1 readily dissociates ethylene in solution and upon exposure to 1 atm of H2 is capable of carrying out the hydrogenation of ethylene. The characterization of two Rh-H species by multinuclear NMR spectroscopy is provided. The reactivity of 1 towards the catalytic hydrogenation of alkenes and alkynes at room temperature and 1 atm of H2 is reported and compared to the activity of Wilkinson's catalyst under the same reaction conditions.
- Perez, Viridiana,Audet, Pierre,Bi, Wenhua,Fontaine, Frédéric-Georges
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p. 2130 - 2137
(2016/02/09)
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- Reduced graphene oxide supported nickel-palladium alloy nanoparticles as a superior catalyst for the hydrogenation of alkenes and alkynes under ambient conditions
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Addressed herein is the superior catalytic performance of reduced graphene oxide supported Ni30Pd70 alloy nanoparticles (rGO-Ni30Pd70) for the direct hydrogenation of alkenes and alkynes to alkanes, which surpasses the commercial Pd/C catalyst both in activity and stability. A variety of cyclic or aromatic alkenes and alkynes (a total of 17 examples) were rapidly reduced to the corresponding alkanes with high yields (>99%) via the presented direct hydrogenation protocol under ambient conditions. Compared to the commercially available Pd/C (10 wt%) catalyst, the rGO-Ni30Pd70 catalyst provided higher yields in shorter reaction times under the optimized conditions. Moreover, the rGO-Ni30Pd70 catalysts were more stable and durable than the commercial Pd/C catalysts by preserving their initial activity after five consecutive runs in the hydrogenation reactions.
- ?etinkaya, Yasin,Metin, ?nder,Balci, Metin
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p. 28538 - 28542
(2016/04/08)
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- Alkene hydrogenation over palladium supported on a carbon–silica material
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Palladium catalysts supported on a carbon–silica material were synthesized. Hydrogenation by molecular hydrogen was studied in the presence of straight-chain and cyclic olefins. As distinct from what is observed for olefins having a phenyl substituent, for aliphatic alkenes the reaction rate decreases with an increasing conversion due to the accumulation of hydrogenation products. The synthesized palladium catalysts show a higher hydrogenation activity than Pd/C.
- Akchurin,Baibulatova,Grabovskii,Talipova,Galkin,Dokichev
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p. 586 - 591
(2016/10/18)
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- Evaluated kinetics of the reactions of H and CH3 with n-alkanes: Experiments with n-butane and a combustion model reaction network analysis
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Presented is a combined experimental and modeling study of the kinetics of the reactions of H and CH3 with n-butane, a representative aliphatic fuel. Abstraction of H from n-alkane fuels creates alkyl radicals that rapidly decompose at high temperatures to alkenes and daughter radicals. In combustion and pyrolysis, the branching ratio for attack on primary and secondary hydrogens is a key determinant of the initial olefin and radical pool, and results propagate through the chemistry of ignition, combustion, and byproduct formation. Experiments to determine relative and absolute rate constants for attack of H and CH3 have been carried out in a shock tube between 859 and 1136 K for methyl radicals and 890 to 1146 K for H atoms. Pressures ranged from 140 to 410 kPa. Appropriate precursors are used to thermally generate H and CH3 in separate experiments under dilute and well-defined conditions. A mathematical design algorithm has been applied to select the optimum experimental conditions. In conjunction with postshock product analyses, a network analysis based on the detailed chemical kinetic combustion model JetSurf 2 has been applied. Polynomial chaos expansion techniques and Monte Carlo methods are used to analyze the data and assess uncertainties. The present results provide the first experimental measurements of the branching ratios for attack of H and CH3 on primary and secondary hydrogens at temperatures near 1000 K. Results from the literature are reviewed and combined with the present data to generate evaluated rate expressions for attack on n-butane covering 300 to 2000 K for H atoms and 400 to 2000 K for methyl radicals. Values for generic n-alkanes and related hydrocarbons are also recommended. The present experiments and network analysis further demonstrate that the C-H bond scission channels in butyl radicals are an order of magnitude less important than currently indicated by JetSurf 2. Updated rate expressions for butyl radical fragmentation reactions are provided.
- Manion, Jeffrey A.,Sheen, David A.,Awan, Iftikhar A.
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p. 7637 - 7658
(2015/07/27)
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- Rational design of Ni-based catalysts derived from hydrotalcite for selective hydrogenation of 5-hydroxymethylfurfural
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Selective hydrogenation of 5-hydroxymethylfurfural (HMF) is of great importance for future energy and chemical supply. Herein, we propose for the first time that non-noble Ni-Al2O3 catalysts derived from hydrotalcite-like compounds can efficiently and selectively convert HMF into 2,5-dimethylfuran (DMF), 2,5-dimethyltetrahydrofuran (DMTHF) and 2,5-dihydroxymethyltetrahydrofuran (DHMTHF). Homogeneous elemental distributions of the hydrotalcite-like precursor facilitate good dispersion of Ni and Al2O3 species and strong interaction between them over the resulting catalysts. The catalysts therefore exhibited superior reactivity. Through fine modulation of surface metal-acid bifunctional sites and control of reaction conditions, high yields of DMF (91.5%), DMTHF (97.4%) and DHMTHF (96.2%) can be diversely achieved. The results demonstrate the feasibility of Ni catalysts for selective hydrogenation of C=O, C=C and C-O bonds, which have great potential for biomass utilization.
- Kong, Xiao,Zheng, Runxiao,Zhu, Yifeng,Ding, Guoqiang,Zhu, Yulei,Li, Yong-Wang
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p. 2504 - 2514
(2015/04/22)
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- Palladium nanoparticles encapsulated in a dendrimer networks as catalysts for the hydrogenation of unsaturated hydrocarbons
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A novel method has been proposed for encapsulating palladium nanoparticles up to 5 nm in the matrix of polymeric support networks based on polyamidoamine dendrimers. The shape of the particle size distribution and the catalytic activity of the materials obtained during the hydrogenation of unsaturated compounds depend strongly on the support structure. High activity (TOF up to 86,000 h-1) has been observed during the hydrogenation of styrene.
- Karakhanov, Edward A.,Maksimov, Anton L.,Zakharian, Elena M.,Kardasheva, Yulia S.,Savilov, Sergey V.,Truhmanova, Nadezhda I.,Ivanov, Andrey O.,Vinokurov, Vladimir A.
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-
- 1,2,3-Triazolylidene ruthenium(ii)-cyclometalated complexes and olefin selective hydrogenation catalysis
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Silver(i) 1,2,3-triazol-5-ylidenes [(RCH2C2N2(NMe)Ph)2Ag][AgCl2] (R = Ph 3a, C6H2iPr33b, C6H2Me33c) and [(PhCH2C2N2(NMe)R)2Ag][AgCl2] (R = C6H4Me 3d, C6H4CF33e) were synthesized and subsequently treated with RuHCl(PPh3)3 and RuHCl(H2)(PCy3)2. The reaction of 3a with RuHCl(PPh3)3 gave RuHCl(PPh3)2(PhCH2C2N2(NMe)Ph) (4a1) as the minor product and the cyclometalated complex RuCl(PPh3)2(PhCH2C2N2(NMe)C6H4) (4a2) as the major product. However, similar reaction with 3b selectively formed the cyclometalated complex RuCl(PPh3)2((C6H2iPr3)CH2C2N2(NMe)C6H4) (4b2). Similarly the silver(i) triazolylidenes 3a and 3b were reacted with RuHCl(H2)(PCy3)2; gave RuHCl(PCy3)2(PhCH2C2N2(NMe)Ph) (5a1), RuCl(PCy3)2(PhCH2C2N2(NMe)C6H4) (5a2) and RuCl(PCy3)2((C6H2iPr3)CH2C2N2(NMe)C6H4) (5b2), respectively. Species 3c, 3d and 3e resulted in the cyclometalated complexes (5c2, 5d2 and 5e2) as the major products as well as the ruthenium-hydride complexes (5c1, 5d1 and 5e1) as the minor products. The cyclometalated species are derived from the ruthenium-hydride complexes via C(sp2)-H activation. These Ru-complexes were shown to act as hydrogenation catalyst precursors for olefinic substrates including those containing a variety of functional groups. This journal is
- Bagh, Bidraha,McKinty, Adam M.,Lough, Alan J.,Stephan, Douglas W.
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p. 2712 - 2723
(2015/02/19)
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- MONONUCLEAR IRON COMPLEX AND ORGANIC SYNTHESIS REACTION USING SAME
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Provided is a mononuclear iron complex that comprises an iron-silicon bond that is represented by formula (1) and that exhibits excellent catalyst activity in each of a hydrosilylation reaction, a hydrogenation reaction, and reduction of a carbonyl compound. In formula (1), R 1 -R 6 either independently represent an alkyl group, an aryl group, an aralkyl group or the like that may be substituted with a hydrogen atom or X, or represent a crosslinking substituent in which at least one pair comprising one of R 1 -R 3 and one of R 4 -R 6 is combined. X represents a halogen atom, an organoxy group, or the like. L represents a two-electron ligand other than CO. When a plurality of L are present, the plurality of L may be the same as or different from each other. When two L are present, the two L may be bonded to each other. n and m independently represent an integer of 1 to 3 with the stipulation that n+m equals 3 or 4.
- -
-
Paragraph 0233-0235
(2016/12/01)
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- Highly dispersed Pd nanoparticles supported on nitrogen-doped graphene with enhanced hydrogenation activity
-
Pd nanoparticles supported on nitrogen-doped graphene (NG) were prepared as hydrogenation catalysts. Different nitrogen sources (ethylenediamine, ammonia, and urea) were employed to synthesize NG using hydrothermal treatment under mild conditions. The as-made samples were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, elemental analysis, nitrogen adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. Remarkably improved dispersion of Pd nanoparticles was observed when nitrogen was introduced into the graphene structure. These NG-supported Pd catalysts showed enhanced catalytic hydrogenation activities owing to the superior dispersion of Pd. In the hydrogenation of different olefins, perfect turnover frequencies were obtained over the NG-supported Pd catalyst with urea as the nitrogen source.
- Liu, Ping,Li, Gen,Chang, Wan-Ting,Wu, Meng-Yao,Li, Yong-Xin,Wang, Jun
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p. 72785 - 72792
(2015/09/15)
-
- MONONUCLEAR RUTHENIUM COMPLEX AND ORGANIC SYNTHESIS REACTION USING SAME
-
Provided is a mononuclear ruthenium complex that comprises a ruthenium-silicon bond that is represented by formula (1) and that exhibits excellent catalyst activity in each of a hydrosilylation reaction, a hydrogenation reaction, and reduction of a carbonyl compound. In formula (1), R 1 -R 6 either independently represent an alkyl group, an aryl group, an aralkyl group or the like that may be substituted with a hydrogen atom or X, or represent a crosslinking substituent in which at least one pair comprising one of R 1 -R 3 and one of R 4 -R 6 is combined. X represents a halogen atom, an organoxy group, or the like. L represents a two-electron ligand other than CO and phosphine. When a plurality of L are present, the plurality of L may be the same as or different from each other. When two L are present, the two L may be bonded to each other. n and m independently represent an integer of 1 to 3 with the stipulation that n+m equals 3 or 4.
- -
-
Paragraph 0206-0207; 0215
(2017/01/02)
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- Cyclooctane metathesis catalyzed by silica-supported tungsten pentamethyl [(ΞSiO)W(Me)5]: Distribution of macrocyclic alkanes
-
Metathesis of cyclic alkanes catalyzed by the new surface complex [(ΞSiO)W(Me)5] affords a wide distribution of cyclic and macrocyclic alkanes. The major products with the formula CnH2n are the result of either a ring contraction or ring expans
- Riache, Nassima,Callens, Emmanuel,Samantaray, Manoja K.,Kharbatia, Najeh M.,Atiqullah, Muhammad,Basset, Jean-Marie
-
supporting information
p. 15089 - 15094
(2015/02/19)
-
- A covalently anchored 2,4,6-triallyloxy-1,3,5-triazine Pd(ii) complex over a modified surface of SBA-15: Catalytic application in hydrogenation reaction
-
Highly efficient and reusable SBA-15-TAT-Pd(ii) has been synthesized by anchoring a 2,4,6-triallyloxy-1,3,5-triazine (TAT) complex over the organo-functionalized surface of SBA-15. The physiochemical properties of the organo-functionalized catalyst were analyzed by elemental analysis, ICP-OES, XRD, N2 sorption measurement isotherm, TGA & DTA, solid state 13C, 29Si NMR spectra, FT-IR, XPS, DRS UV-visible, SEM and TEM. XRD & N2 sorption were analyzed to find out the textural properties of the synthesized catalyst and confirm that an ordered mesoporous channel structure was retained even after the multistep synthetic procedures. The electronic environment and oxidation state of Pd in SBA-15-TAT-Pd(ii) were monitored by XPS and DRS UV-visible techniques. The catalytic activity of the synthesized catalyst SBA-15-TAT-Pd(ii) was screened for hydrogenation reactions and shows higher catalytic activity with good turnover numbers (TON) under optimized experimental conditions with maximum conversion (>99%) and selectivity (100%). The anchored solid catalyst can be recycled efficiently and reused upto five times without major loss in reactivity. This journal is
- Sharma, Priti,Singh
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p. 58467 - 58475
(2015/02/19)
-
- Half sandwich ruthenium(ii) hydrides: Hydrogenation of terminal, internal, cyclic and functionalized olefins
-
Bis(1,2,3-triazolylidene) silver(i) complex 1a was reacted with [RuCl2(p-cymene)]2 to give the ruthenium complex [PhCH2N2(NMe)C2(C6H4CF3)]RuCl2(p-cymene) (2a) as major product in addition to the minor C(sp2)-H activated product [PhCH2N2(NMe)C2(C6H3CF3)]RuCl(p-cymene) (2a′). Similar ruthenium complexes 2b, 2c, 2d and 2e with general formula RuCl2(p-cymene)(NHC) (NHC = MesCH2N2(NMe)C2Ph 2b, PhCH2N2(NMe)C2Ph 2c, TripCH2N2(NMe)C2Ph 2d, IMes 2e) were also synthesized. Subsequent reaction of Me3SiOSO2CF3 with 2a and 2b resulted in cationic ruthenium species [(PhCH2N2(NMe)C2(C6H4CF3))RuCl(p-cymene)][OSO2CF3] (3a) and [(MesCH2N2(NMe)C2Ph)RuCl(p-cymene)][OSO2CF3] (3b), respectively. Complexes 3a and 3b dissolved in CD3CN to give [(PhCH2N2(NMe)C2(C6H4CF3))RuCl(CD3CN)(p-cymene)][OSO2CF3] (4a) and [(MesCH2N2(NMe)C2Ph)RuCl(CD3CN)(p-cymene)][OSO2CF3] (4b), respectively. Cationic ruthenium species 4a and 4b failed to show catalytic activity towards hydrogenation of olefins. Ruthenium(ii) complexes 2b-e with the general formula RuCl2(p-cymene)(NHC) were reacted with Et3SiH to generate a series of ruthenium(ii) hydrides 5b-e. These compounds 5b-e are effective catalysts for the hydrogenation of terminal, internal and cyclic and functionalized olefins.
- Bagh, Bidraha,Stephan, Douglas W.
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p. 15638 - 15645
(2015/01/08)
-
- Reductive dimerization and oligomerization of alcohols, ketones, and aldehydes to hydrocarbons on a promoted, fused iron catalyst
-
A new reductive dimerization and oligomerization reaction of (C5 and C6) cycloalkanols and cycloalkanones, benzaldehyde, and benzyl alcohol to hydrocarbons containing as many, or more, carbon atoms as the reactant oxygenated compound on a promoted, fused iron catalyst proceeds at a temperature of 250-350°C, a hydrogen pressure of 0.1-1 MPa, a specific feed rate of oxygenated reagent of 80-320 g h-1kg-1Ct, and a hydrogen space velocity of 1 × 103 to 20 × 103 h-1. Possible reaction mechanisms have been considered.
- Glebov,Zaikin,Mikaya,Kliger
-
p. 296 - 308
(2014/08/05)
-
- Conversion of furfural into cyclopentanone over Ni-Cu bimetallic catalysts
-
The conversion of furfural into cyclopentanone over Ni-Cu bimetallic catalysts was studied under hydrogen atmosphere. Furfuryl alcohol, 4-hydroxy-2-cyclopentenone and 2-cyclopentenone were verified as three key intermediates. Rearrangement of the furan ring was independent of hydrogenation, starting from furfuryl alcohol rather than furfural. The opening and closure of the furan ring were closely related to the attack of a H2O molecule on the 5-position of furfuryl alcohol. Prior hydrogenation of the aldehyde group accounted for the different reactivity of furfural and furfuryl alcohol. The high selectivity of cyclopentanone was ascribed to the presence of 2-cyclopentenone.
- Yang, Yanliang,Du, Zhongtian,Huang, Yizheng,Lu, Fang,Wang, Feng,Gao, Jin,Xu, Jie
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p. 1932 - 1940
(2013/09/24)
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- The use of ultrasmall iron(0) nanoparticles as catalysts for the selective hydrogenation of unsaturated C-C bonds
-
The performance of well-defined ultrasmall iron(0) nanoparticles (NPs) as catalysts for the selective hydrogenation of unsaturated C-C and CX bonds is reported. Monodisperse iron nanoparticles of about 2 nm size are synthesized by the decomposition of {Fe(N[Si(CH3)3]2) 2}2 under dihydrogen. They are found to be active for the hydrogenation of various alkenes and alkynes under mild conditions and weakly active for CO bond hydrogenation.
- Kelsen, Vinciane,Wendt, Bianca,Werkmeister, Svenja,Junge, Kathrin,Beller, Matthias,Chaudret, Bruno
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p. 3416 - 3418
(2013/05/22)
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- Catalyst design for iron-promoted reductions: An iron disilyl-dicarbonyl complex bearing weakly coordinating η2-(H-Si) moieties
-
Iron disilyl dicarbonyl complex 1, in which two H-Si moieties of the 1,2-bis(dimethylsilyl)benzene ligand were coordinated to the iron center in an η2-(H-Si) fashion, was synthesized by the reaction of (η4-C6H8)Fe(CO)3 with 2 equiv. of 1,2-bis(dimethylsilyl)benzene under photo-irradiation. Complex 1 demonstrated high catalytic activity toward the hydrogenation of alkenes, the hydrosilylation of alkenes and the reduction of carbonyl compounds.
- Sunada, Yusuke,Tsutsumi, Hironori,Shigeta, Keisuke,Yoshida, Ryota,Hashimoto, Toru,Nagashima, Hideo
-
supporting information
p. 16687 - 16692
(2013/12/04)
-
- PROCESS FOR THE CONVERSION OF LIGNIN TO LIQUID HYDROCARBONS
-
Process for the conversion of lignin to liquid hydro-carbons comprising: subjecting the lignin to hydrogenolysis in the presence of at least one hydrogenolysis catalyst, at a temperature ranging from 250° C. to 350° C., preferably ranging from 290° C. to 320 ° C., so as to obtain depolymerized lignin; subjecting said depolymerized lignin to hydrotreating so as to obtain a mixture of liquid hydrocarbons. Said liquid hydrocarbons can be used as such (biofuels) for the production of reformulated gasolines, or they can be used for the production of gasolines or of gas oils through conventional refining processes.
- -
-
Paragraph 0153-0176
(2013/03/26)
-
- ZEOLITIC CATALYTIC CONVERSION OF ALCOHOLS TO HYDROCARBONS
-
A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100°C and up to 550°C, wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.
- -
-
Page/Page column 19
(2013/02/28)
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- Sorbitol transformation in aqueous medium: Influence of metal/acid balance on reaction selectivity
-
The effect of the metal/acid balance of Pt/SiO2-Al 2O3 catalysts on the catalytic transformation of sorbitol in aqueous medium was investigated, using four mechanical mixtures of Pt/SiO2-Al2O3 and SiO2-Al 2O3 (100:0; 50:50; 25:75; 0:100). The results show that the metal/acid balance has a strong impact on catalytic performances, tuning the yields in alkanes, alcohols, ketones and heterocycles. An optimum in the metal/acid balance is obtained with the 50:50 mechanical mixture: when the metallic function is introduced in higher quantity, the C-C cleavage pathway is favoured and leads to an important CO2 yield; on the contrary, a too low proportion of platinum atoms induces a lack of metallic sites for the hydrogenation reaction. Nevertheless many hydrocarbons containing 1-4 carbon atoms are still obtained with the best balanced catalyst, evidencing some C-C cleavage activity. Hydrocarbon selectivity could be improved by new more hydrogenating metallic phases and new supports with a stronger acidity in water.
- Vilcocq,Cabiac,Especel,Lacombe,Duprez
-
experimental part
p. 117 - 122
(2012/09/08)
-
- Acceptorless photocatalytic dehydrogenation for alcohol decarbonylation and imine synthesis
-
It has come to light: Renewed interest in conversions of highly oxygenated materials has motivated studies of the organometallic-catalyzed photocatalytic dehydrogenative decarbonylation of primary alcohols into alkanes, CO, and H2 (see scheme). Methanol, ethanol, benzyl alcohol, and cyclohexanemethanol are readily decarbonylated. The photocatalysts are also active for amine dehydrogenation to give N-alkyl aldimines and H2.
- Ho, Hung-An,Manna, Kuntal,Sadow, Aaron D.
-
supporting information; experimental part
p. 8607 - 8610
(2012/09/11)
-
- Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
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A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
- Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
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supporting information; experimental part
p. 6146 - 6159
(2012/05/07)
-
- Assembly and post-modification of a metal-organic nanotube for highly efficient catalysis
-
A metal-organic nanotube (MONT) was synthesized by linking up the bent organic ligands and the tetra-coordinated zinc cations under mild conditions. Structural analysis revealed that the MONT has a very large exterior wall diameter of 4.91 nm and an interior channel diameter of 3.32 nm. Interlocking of the nanotubes gives rise to a 3D chiral framework containing 1D helical cylindered channels with diameter of 2.0 nm. The MONT has very interesting property by synergizing the functionality of nanotubes, metal-organic frameworks (MOFs), and N-heterocyclic carbenes (NHCs). The dye adsorption experiments demonstrate that the channels of the MONTs are accessible to large reagents typically used for catalysis. The postmodification of the MONT can be easily operated by unmarking the imidazolium moieties in the channel walls, which was conducted as a highly active heterogeneous catalyst for Suzuki-Miyaura and Heck coupling reactions, hydrogenation of olefins and nitrobenzene, while the constituent elements are less efficient for these reactions under the same conditions.
- Kong, Guo-Qiang,Ou, Sha,Zou, Chao,Wu, Chuan-De
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p. 19851 - 19857
(2013/02/22)
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- Stoichiometric and catalytic reactions of thermally stable nickel(0) NHC complexes
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Although there are many organic reactions that are catalyzed by either Ni0 or Pd0 complexes, in comparison with the case for Pd0 there has been significantly less work studying coordinatively unsaturated Ni0 complexes. Here, we develop a simple synthetic route for preparing a number of thermally stable NHC-supported Ni0 hexadiene complexes in good yield. We examine the stoichiometric reactivity of one of these species and demonstrate that the coordinated hexadiene moiety is labile and can be replaced with a variety of different ligands, including CO, phosphines, isonitriles, and olefins. In addition, we show that the Ni 0 hexadiene complexes are relatively rare examples of homogeneous first-row transition-metal catalysts for the hydrogenation of olefins.
- Wu, Jianguo,Faller, John W.,Hazari, Nilay,Schmeier, Timothy J.
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scheme or table
p. 806 - 809
(2012/05/04)
-
- PEG-anchored rhodium polyether diphosphinite complex as an efficient homogeneous and recyclable catalyst for hydroaminomethylation of olefins
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A recyclable rhodium polyether diphosphinite complex anchored in polyethylene glycol [RhPEGD] was studied for hydroaminomethylation of various olefins with primary and secondary amines. The protocol was optimized with respect to various reaction parameters and the general applicability of catalyst for hydroaminomethylation of different functionalized olefins with corresponding amines was investigated. During the course of reaction, catalyst was soluble with reactants/products while could be quantitatively separated from reaction media in biphasic form by addition of anti-solvent on completion of reaction. The catalyst exhibited remarkable activity and was subsequently recycled up to five consecutive cycles.
- Khan, Shoeb R.,Khedkar, Mayur V.,Qureshi, Ziyauddin S.,Bagal, Dattatraya B.,Bhanage, Bhalchandra M.
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experimental part
p. 141 - 145
(2012/01/15)
-
- Iron nanoparticles supported on chemically-derived graphene: Catalytic hydrogenation with magnetic catalyst separation
-
Iron nanoparticles (Fe-NP) supported on chemically-derived graphene (CDG) were prepared and identified as an effective catalyst for the hydrogenation of alkenes and alkynes. The catalyst canh easily be separated by magnetic decantation.
- Stein, Mario,Wieland, Joerg,Steurer, Peter,Toelle, Folke,Muelhaupt, Rolf,Breit, Bernhard
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supporting information; experimental part
p. 523 - 527
(2011/04/22)
-
- Hydrodefluorination and other hydrodehalogenation of aliphatic carbon-halogen bonds using silylium catalysis
-
Trialkylsilylium cation equivalents partnered with halogenated carborane anions (such as Et3Si[HCB11H5Cl6]) function as efficient and long-lived catalysts for hydrodehalogenation of C-F, C-Cl, and C-Br bonds with trialkylsilanes as stoichiometric reagents. Only C(sp3)-halogen bonds undergo this reaction. The range of C-F bond-containing substrates that participate in this reaction is quite broad and includes simple alkyl fluorides, benzotrifluorides, and compounds with perfluoroalkyl groups attached to an aliphatic chain. However, CF4 has proven immune to this reaction. Hydrodechlorination was carried out with a series of alkyl chlorides and benzotrichlorides, and hydrodebromination was studied only with primary alkyl bromide substrates. Competitive experiments established a pronounced kinetic preference of the catalytic system for activation of a carbon-halogen bond of a lighter halide in primary alkyl halides. On the contrary, hydrodechlorination of C6F 5CCl3 proceeded much faster than hydrodefluorination of C6F5CF3 in one-pot experiments. A solid-state structure of Et3Si[HCB11H5Cl6] was determined by X-ray diffraction methods.
- Douvris, Christos,Nagaraja,Chen, Chun-Hsing,Foxman, Bruce M.,Ozerov, Oleg V.
-
supporting information; experimental part
p. 4946 - 4953
(2010/06/17)
-
- Carbon-carbon coupling of C(sp3)-F bonds using alumenium catalysis
-
Dialkylalumenium cation equivalents coupled with the hexabromocarborane anion function as efficient and long-lived catalysts for alkylation of aliphatic C-F bonds (alkylative defluorination or AlkDF) by alkylaluminum compounds. Only C(sp3)-F bo
- Gu, Weixing,Haneline, Mason R.,Douvris, Christos,Ozerov, Oleg V.
-
experimental part
p. 11203 - 11212
(2009/12/05)
-
- Palladium catalyzed hydrogenation of bio-oils and organic compounds
-
The invention provides palladium-catalyzed hydrogenations of bio-oils and certain organic compounds. Experimental results have shown unexpected and superior results for palladium-catalyzed hydrogenations of organic compounds typically found in bio-oils.
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Page/Page column 8-9
(2008/12/08)
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- Hydrogenation of aromatic compounds
-
A process for hydrogenating aromatic compounds to produce hydrogenated cyclic compound by contacting an aromatic compound with hydrogen under conditions of pressure and temperature to react the hydrogen and aromatic compound in the presence of a catalyst comprising from 4 to 14 wt. % Ni and 0.0 up to about 0.9 wt. % Cu deposited on a transition alumina support having BET surface area of from about 40 to 180 m2/g, and pore volume of from about 0.3 to about 0.8 cc/g, preferably in the presence of a solvent boiling at least 10° F. higher than the aromatic compound and the hydrogenated cyclic compound, such as the hydrogenation of benzene to produce cyclohexane.
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Page/Page column 2-3
(2008/06/13)
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- Moving bed process for producing propylene, recycling a fraction of used catalyst
-
The invention concerns a process for producing propylene from a steam cracking and/or catalytic cracking light olefinic cut, said process comprising a moving bed catalytic cracking step with a catalyst regeneration loop. The process recycles a portion of the used catalyst to the inlet of the moving bed reactor. The conversion is high using the process of the invention, with a good yield and good propylene selectivity.
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Page/Page column 5-6
(2008/06/13)
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