- Dehydrogenative ester synthesis from enol ethers and water with a ruthenium complex catalyzing two reactions in synergy
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We report the dehydrogenative synthesis of esters from enol ethers using water as the formal oxidant, catalyzed by a newly developed ruthenium acridine-based PNP(Ph)-type complex. Mechanistic experiments and density functional theory (DFT) studies suggest that an inner-sphere stepwise coupled reaction pathway is operational instead of a more intuitive outer-sphere tandem hydration-dehydrogenation pathway.
- Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Luo, Jie,Milstein, David,Rauch, Michael
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supporting information
p. 1481 - 1487
(2022/03/07)
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- Aromatic compound hydrogenation and hydrodeoxygenation method and application thereof
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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.
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Paragraph 0094-0095; 0123-0126; 0128-0130
(2021/05/29)
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- Selective hydrogenation of lignin-derived compounds under mild conditions
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A key challenge in the production of lignin-derived chemicals is to reduce the energy intensive processes used in their production. Here, we show that well-defined Rh nanoparticles dispersed in sub-micrometer size carbon hollow spheres, are able to hydrogenate lignin derived products under mild conditions (30 °C, 5 bar H2), in water. The optimum catalyst exhibits excellent selectivity and activity in the conversion of phenol to cyclohexanol and other related substrates including aryl ethers.
- Chen, Lu,Van Muyden, Antoine P.,Cui, Xinjiang,Laurenczy, Gabor,Dyson, Paul J.
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p. 3069 - 3073
(2020/06/17)
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- Phosphine-free cobalt catalyst precursors for the selective hydrogenation of olefins
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Cobalt(ii) complexes bearing phosphine-free tridentate NNS ligands were prepared. Depending on the ligand, dimeric or monomeric complexes were isolated. Monomeric Co(NNMeS)Cl2 selectively catalysed the hydrogenation of olefins in the presence of reducible moieties such as ketones. Further investigation showed that this complex functions as a nanoparticle precursor under the reaction conditions.
- Puylaert, Pim,Dell'Acqua, Andrea,El Ouahabi, Fatima,Spannenberg, Anke,Roisnel, Thierry,Lefort, Laurent,Hinze, Sandra,Tin, Sergey,De Vries, Johannes Gerardus
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- Ruthenium Nanoparticles Stabilized in Cross-Linked Dendrimer Matrices: Hydrogenation of Phenols in Aqueous Media
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Novel catalysts consisting of ruthenium nanoparticles encapsulated in cross-linked matrices based on the poly(propylene imine) dendrimers of the 1st and 3rd generations have been synthesized with a narrow particle size distribution (3.8 and 1.0 nm, respectively). The resulting materials showed high activity for the hydrogenation of phenols in aqueous media (specific catalytic activity reached turnover frequencies of 2975h-1 with respect to hydrogen uptake). It has been shown that the use of water as a solvent leads to a 1.5 to 50-fold increase in the reaction rate depending upon the nature of the substrate. It has been established that unlike the traditional heterogeneous catalysts based on ruthenium, during the hydrogenation of dihydroxybenzenes, the hydrogenation rate decreases in the order: resorcinol>hydroquinoneacatechol. The maximum specific activity for resorcinol was a turnover frequency of 243150h-1 with respect to hydrogen uptake. The catalyst based on the dendrimer of the 3rd generation containing finer particles has significantly inferior activity to the catalyst based on the dendrimer of the 1st generation by virtue of steric factors, as well as the need for prereduction of the ruthenium oxide contained on the surface. These catalysts showed resistance to metal leaching and may be reused several times without loss of activity.
- Maximov, Anton,Zolotukhina, Anna,Murzin, Vadim,Karakhanov, Edward,Rosenberg, Edward
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p. 1197 - 1210
(2015/04/14)
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- Titanium nitride-nickel nanocomposite as heterogeneous catalyst for the hydrogenolysis of aryl ethers
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Lignin from biomass can become a sustainable source of aromatic compounds. Its depolymerization can be accomplished through hydrogenolysis, although the development of catalysts based on cheap and abundant metals is lacking. Herein, a sustainable composite based on titanium nitride and nickel is synthesized and employed as catalyst for the hydrogenolysis of aryl ethers as models for lignin. The catalytic activity of the new material during hydrogenation reactions is proven to be superior to that of either component alone. In particular, different aryl ethers could be efficiently converted under relatively mild conditions into aromatic compounds and cycloalkanes within minutes.
- Molinari, Valerio,Giordano, Cristina,Antonietti, Markus,Esposito, Davide
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supporting information
p. 1758 - 1761
(2014/03/21)
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- Hydrogenation of phenols in ionic liquids on rhodium nanoparticles
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A new catalyst system based on rhodium nanoparticles stabilized by polyacrylic acid have been suggested for the hydrogenation of phenols in ionic liquids. It has been shown that high near-quantitative yields of reaction products are achieved in ionic liquids containing a tetraalkylammonium cation. By the TEM and XPS techniques it has been revealed that the use of ionic liquids substantially decreases the particle size and reduces the aggregation of nanoparticles through the inclusion of the ionic liquid cations into the surface layer along with polyacrylic acid.
- Maksimov,Kuklin,Kardasheva,Karakhanov
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p. 157 - 163
(2013/07/27)
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- Reductive splitting of cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride
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The depolymerization of cellulose is carried out in the ionic liquid 1-butyl-3-methylimidazolium chloride in the presence of hydrogen gas. First, the ketal 1,1-diethoxycyclohexane and cel-lobiose were used as model substrates. For the depolymerization of cellulose itself, the combination of a heterogeneous metal catalyst and a homogeneous ruthenium catalyst proved effective. One of the possible roles of the ruthenium compound is to enhance the transfer of hydrogen to the metallic surface. The cellulose is fully converted under relatively mild conditions, with sorbitol as the dominant product in 51-74% yield.
- Ignatyev, Igor A.,Doorslaer, Charlie Van,Mertens, Pascal G. N.,Binnemans, Koen,De Vos, Dirk E.
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body text
p. 91 - 96
(2011/02/22)
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- Highly selective dehydrogenative silylation of alkenes catalyzed by rhenium complexes
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Rhenium(I) complexes of type [ReBr2(L)(NO)(PR3) 2] (L = H2 (1), CH3CN (2), and ethylene (3); R = iPr (a) and cyclohexyl (Cy; b)) catalyze dehydrogenative silylation of alkenes in a highly selective ma
- Jiang, Yanfeng,Blacque, Olivier,Fox, Thomas,Freeh, Christian M.,Berke, Heinz
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supporting information; experimental part
p. 2121 - 2128
(2009/09/30)
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- Syntheses and conformational analyses of mono- and trans-1,4-dialkoxy substituted cyclohexanes-the steric substituent/skeleton interactions
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Mono- and trans-1,4-dialkoxy substituted cyclohexanes (alkyl=Me, Et, i-Pr, t-Bu) were prepared using the solvomercuration-demercuration (SM-DM) procedure. The axial?axial and axial,axial?equatorial, equatorial conformational equilibria of the products wer
- Kleinpeter, Erich,Thielemann, J?rg
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p. 9071 - 9081
(2008/02/09)
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- γ-Ray-induced reduction of sterically hindered alkyl carboxylates with trichlorosilane in the presence of hydrogen chloride. Two-step mechanism for the formation of alkanes via the alkyl chloride
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γ-Irradiation of a mixture of 1-adamantyl acetate and trichlorosilane (TCS) in the presence of hydrogen chloride yields adamantane. The first step of this reaction entails cleavage of the alkyloxygen bond by the action of HCl and TCS to give the alkyl chloride. The chloride, in the second step, is dechlorinated by TCS by a known, free-radical mechanism. t-Amyl and benzyl acetates react analogously to 1-adamantyl acetate in this system to give isopentane and toluene, whereas other primary and secondary alkyl derivatives produce the corresponding dialkyl ethers by a known, free-radical mechanism.
- Oka, Kunio,Nakao, Ren
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- SELECTIVE DESULFURIZATION OF 1,3-DITHIANES, -OXATHIOLANES AND -THIAZOLIDINES BY TRIBUTYLTIN HYDRIDE
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Selective desulfurization of 2-alkyl-1,3-dithianes, -oxathiolanes, or -thiazolidines 1 with one equivalent of tri-n-butyltin hydride yields acyclic compounds R1R2CHX(CH2)nSSnBu3 (X=S,O,NH; n=2,3), (2) which can be destannylated to the corresponding mercaptans 3.
- Schmidt, K.,O'Neal, S.,Chan, T.C.,Alexis, C.P.,Uribe, J.M.,et al.
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p. 7301 - 7304
(2007/10/02)
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- Reduction of Thionoesters to Ethers by Triorganotin Hydrides
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Esters 1 are efficiently deoxygenated to the corresponding ethers 3 in two steps by first conversion to the thionoesters 2 and subsequent reduction of these by triorganotin hydrides.
- Smith, Colin,Tunstad, Linda M.,Gutierrez, Carlos G.
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p. 257 - 260
(2007/10/02)
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- General Ether Synthesis under Mild Acid-Free Conditions. Trimethylsilyl Iodide Catalyzed Reductive Coupling of Carbonyl Compounds with Trialkylsilanes to Symmetrical Ethers and Reductive Condensation with Alkoxysilanes to Unsymmetrical Ethers
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Facile synthesis of symmetrical ethers is achieved by either trimethylsilyl triflate or trimethylsilyl iodide catalyzed reductive coupling of carbonyl compounds (aldehydes and ketones) with trialkylsilanes.The method was also extended to the trimethylsilyl iodide catalyzed preparation of unsymmetrical ethers by reductive condensation (of carbonyl compounds) with alkoxysilanes.The scope and limitations of the reactions are discussed with emphasis on diastereoselectivity.
- Sassaman, Mark B.,Kotian, Kirtivan D.,Prakash, G. K. Surya,Olah, George A.
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p. 4314 - 4319
(2007/10/02)
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- Addition of Alcohol to Olefinic Bonds by Paired Electrosynthesis with Raney-Nickel Cathode
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A one-pot addition reaction of an alcohol to an olefinic double bond was successfully performed by use of paired electrosynthesis with a Raney-nickel cathode.
- Yamada, Tsukasa,Osa, Tetsuo,Matsue, Tomokazu
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p. 995 - 996
(2007/10/02)
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- Mechanism of Hydrogenolysis. Part 1. Catalytic Hydrogenation of Vinyl and Aryltrifluoromethanesulphonates
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A concerted cleavage of the C-O bond by the MH2 species is proposed for the first step of the catalytic hydrogenation of vinyl and aryl trifluoromethanesulphonates.The alkene thus generated in the case of vinyl trifluoromethanesulphonates, is subsequently, reduced to an alkane.The stereochemistry of the reduction of vinyl trifluoromethanesulphonates is therefore identical to that observed in the reduction of the corresponding alkenes.
- Martinez, Antonio Garcia,Alvarez, Roberto Martinez,Aguirre, Juan Arranz,Subramanian, R. L.
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p. 1595 - 1598
(2007/10/02)
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- Solvomercuration-Demercuration. 12. The Solvomercuration-Demercuration of Olefins in Alcohol Solvents with Mercuric Trifluoroacetate--An Ether Synthesis of Wide Generality
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Studies on the solvomercuration-demercuration (SM-DM) of olefins in methyl, ethyl, isopropyl, and tert-butyl alcohols with mercuric trifluoroacetate have been extended. 1-Dodecene undergoes the SM-DM sequence with typical results for a monosubstituted olefin.Cyclopentene similarly exhibited behavior characteristic of a 1,2-disubstituted olefin in methanol, ethanol, and 2-propanol, giving high yields, >90percent of the corresponding ethers.However, in tert-butyl alcohol, the yields of ether were lower than normal and decreased somewhat with time. 2-Methyl-1-butene gives >90percent yields of the Markovnikov methyl ether.On the other hand, the yields of ethyl, isopropyl, and tert-butyl ethers are lower and decrease with time.Major improvements in yields, however, are possible by lowering the reaction temperature from room temperature to 0 deg C.Cyclooctene, surprisingly, behaves more like a tri-, tetra-, or isosubstituted olefin than a 1,2-disubstituted olefin.The yields of cyclooctyl methyl ether are >90percent and do not decrease with time.However, yields of the ethyl, isopropyl, and tert-butyl ethers are lower and drop with time.Again, lowering the reaction temperature from room temperature to 0 deg C markedly improves the yields of the cyclooctyl ethers.These results, coupled with those of a previous study, clearly reveal the exceptional superiority of mercuric trifluoroacetate for the SM-DM of olefins in alcohol solvents.
- Brown, Herbert C.,Kurek, Joseph T.,Rei, Min-Hon,Thompson, Kerry L.
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p. 1171 - 1174
(2007/10/02)
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- ALUMINIUM CHLORIDE IN THE IONIC HYDROGENATION OF OXYGEN-CONTAINING COMPOUNDS OF VARIOUS CLASSES
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The ionic hydrogenation of alcohols, ketones, and ketals was realized with triethylsilane in the presence of aluminium chloride.Gaseous hydrogen chloride was used as proton donor during the hydrogenation of the alcohols and ketones.It was established that, depending on the relative amount of aluminium chloride, hydrogenation can be realized with retention of the selectivity exhibited with the triethylsilane-trifluoroacetic acid pair as hydrogenating agent, and the applicability limits of ionic hydrogenation can be extended.The ionic hydrogenation of derivatives of di- and tetrahydropyran was realized for the first time, and the effect of the substrate structure on the reaction was established.
- Kursanov, D. N.,Bolestova, G. I.,Ibatullin, U. G.,Kuramshina, E. A.,Parnes, Z. N.
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p. 2078 - 2085
(2007/10/02)
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- Solvomercuration-Demercuration. 11. Alkoxymercuration-Demercuration of Representative Alkenes in Alcohol Solvents with the Mercuric Salts Acetate, Trifluoroacetate, Nitrate, and Methanesulfonate
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The alkoxymercuration-demercuration of seven representative olefins with the mercuric salts acetate, trifluoroacetate, nitrate, and methanesulfonate, in methyl, ethyl, isopropyl, and tert-butyl alcohols was examined.Mercuric acetate was effective only in methanol and ethanol.On the other hand, mercuric trifluoroacetate was effective in all four solvents, giving in most cases high yields of the corresponding ethers.Both mercuric nitrate and mercuric methanesulfonate were effective in methanol, ethanol, and 2-propanol.However, in several cases poor selectivity for the ether was observed, as evidenced by the formation of significant amounts of side products.Both electronic and steric effects are important factors in the reaction.Moreover, the structure of the olefin has a pronounced effect, both on the types of oxymercurials formed and on their stability to the reaction conditions.
- Brown, Herbert C.,Kurek, Joseph T.,Rei, Min-Hon,Thompson, Kerry L.
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p. 2551 - 2557
(2007/10/02)
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- OXIDATION OF N-ALKYL-N'-TOSYLHYDRAZINES WITH Hg(OAc)2. A NEW SYNTHESIS OF ETHERS
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N-Alkyl-N'-tosylhydrazines with Hg(OAc)2 in the presence of alcohols or phenol give high yields of corresponding ethers.Reactions in the presence of acetic acid are also examined.
- Gasparrini, F.,Caglioti, L.,Misiti, D.,Palmieri, G.,Ballini,R.
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p. 3609 - 3613
(2007/10/02)
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