- Supported homogeneous catalyst makes its own liquid phase
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A catalyst designed for homogeneous catalysis is shown to generate its own liquid phase if deposited onto a support. In this way, a macroscopically heterogeneous catalyst generates a microscopically homogeneous catalytic environment by self-organization. 2,2′-((3,3′-di-tert-butyl-5,5′-dimethoxy-[1,1′-biphenyl]-2,2′-diyl)-bis(oxy))bis(4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane) modified rhodium complexes molecularly adsorbed onto porous silica powder show surprisingly high activity and regioselectivity in the gas-phase hydroformylation of propene to butanal, with no sign of deactivation. Operando IR investigations combined with density functional theory calculations confirm a side reaction: the aldol condensation of the butanal products. These heavier by-products accumulate inside the pores of the catalytic material. IR and gas chromatography show a direct relation between formation of enones, products of the aldol condensation, performance, and stability of the catalytic system. This demonstrates that the aldol condensation products generated in situ act as a solvent providing an ideal environment to the impregnated homogeneous catalyst.
- Kaftan, Andre,Sch?nweiz, Andreas,Nikiforidis, Ioannis,Hieringer, Wolfgang,Dyballa, Katrin M.,Franke, Robert,G?rling, Andreas,Libuda, J?rg,Wasserscheid, Peter,Laurin, Mathias,Haumann, Marco
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- Electrochemical Reduction of Carbon Dioxide to 1-Butanol on Oxide-Derived Copper
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The electroreduction of carbon dioxide using renewable electricity is an appealing strategy for the sustainable synthesis of chemicals and fuels. Extensive research has focused on the production of ethylene, ethanol and n-propanol, but more complex C4 molecules have been scarcely reported. Herein, we report the first direct electroreduction of CO2 to 1-butanol in alkaline electrolyte on Cu gas diffusion electrodes (Faradaic efficiency=0.056 %, j1-Butanol=?0.080 mA cm?2 at ?0.48 V vs. RHE) and elucidate its formation mechanism. Electrolysis of possible molecular intermediates, coupled with density functional theory, led us to propose that CO2 first electroreduces to acetaldehyde-a key C2 intermediate to 1-butanol. Acetaldehyde then undergoes a base-catalyzed aldol condensation to give crotonaldehyde via electrochemical promotion by the catalyst surface. Crotonaldehyde is subsequently electroreduced to butanal, and then to 1-butanol. In a broad context, our results point to the relevance of coupling chemical and electrochemical processes for the synthesis of higher molecular weight products from CO2.
- Chen, Stuart Tze-Jin,García-Muelas, Rodrigo,López, Núria,Martín, Antonio J.,Pérez-Ramírez, Javier,Pablo-García, Sergio,Peng, Yujie,Per, Edwin Yu Xuan,Ting, Louisa Rui Lin,Veenstra, Florentine L. P.,Yeo, Boon Siang
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- Effect of Sodium Cation Addition on the Hydroformylation of Propene over Silica-supported Group VIII Metal Catalysts
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Addition of a sodium cation to silica-supported Rh, Pd, Pt, and Ni catalysts markedly lowers the activation energy of the hydroformylation process without affecting the regioselectivity of the products and facilitates the CO insertion into propyl intermediates.
- Naito, Shuichi,Tanimoto, Mitsutoshi
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- Mechanistic study of ethanol dehydrogenation over silica-supported silver
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A silica-supported Ag catalyst has been shown to be an efficient heterogeneous catalyst for the oxidant-free dehydrogenation of ethanol into acetaldehyde. The reaction mechanism has been investigated by insitu FTIR spectroscopy. The kinetic isotope effects for proton and hydride abstraction have been studied by using CH3CD2OH and CH3CH2OD as labeled reactants. The results indicate that O-H bond activation and the formation of a hydrogen-bonded complex take place on the silica support and that the Ag particles are necessary for the activation of the C-H bond. The kinetic isotope effect (kH/kD) is 1.9 for CH3CD2OH and 1.8 for CH3CH2OD. The concerted mechanism of C-H cleavage on the Ag sites and proton abstraction on the silica sites is proposed to account for the results of the spectroscopic and kinetic experiments.
- Sushkevich, Vitaly L.,Ivanova, Irina I.,Taarning, Esben
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- Kinetics and Mechanism of the Oxidation of Butane-2,3-Diol by Alkaline Hexacyanoferrate (III), Catalyzed by Ruthenium Trichloride
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The kinetics of oxidation of butane-2,3-diol by alkaline hexacyanoferrate (III), catalyzed by ruthenium trichloride has been studied spectrophotometrically.The reaction rate shows a zero-order dependence on oxidant, a first-order dependence on T, a Michaelis-Menten dependence on , and a variation complicated on ->.A reaction mechanism involving the existence of two active especies of catalyst, Ru(OH)2+ and Ru(OH)3, is proposed.Each one of the active species of catalyst forms an intermediate complex with the substrate, which disproportionates in the rate determining step.The complex disproportionation involves a hydrogen atom transfer from the α-C-H of alcohol to the oxygen of hydroxo ligand of ruthenium, to give Ru(II) and an intermediate radical which is then further oxidized.
- Balado, A. Mucientes,Jimenez, F. Santiago,Martin, F. J. Poblete,Castellanos, R. Varon
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- An FT IR Study of the Isomerization and O2 Reaction of n-Butoxy Radicals
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Using the long path FT IR method, we made product studies of the photolysis of n-butyl nitrite (n-C4H9ONO) in ppm concentrations at 700 torr of air and 298 +/- 2 K.Unidentified HO-containing compounds as well as n-butyraldehyde (n-C3H7CHO) were detected.The results provide further evidence for the occurence of the following competitive uni- and bimolecular reaction paths for the ensuing n-butoxy radicals: intramolecular hydrogen-shift isomerization CH3CH2CH2CH2O. -> CH2CH2CH2CH2OH (1), and O2 reaction CH3CH2CH2CH2O. + O2 -> CH3CH2CH2CHO + HO2 (2).From the observed yield of n-C3H7CHO, the relative rate k2/k1 has been determined to be 0.23 +/- 0.03 (2?) at 700 torr of air.
- Niki, H.,Maker, P. D.,Savage, C. M.,Breitenbach, L. P.
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- Hydroformylation of propene heterogeneously catalyzed by HRh(CO)(PPh 3)3 encapsulated in to hexagonal mesoporous silica - Parametric variation and mass transfer study
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An in situ encapsulated HRh(CO)(PPh3)3 in to the pores of hexagonal mesoporous silica (HMS) acting as nanophase reactors, was investigated for the catalytic hydroformylation of propene. The encapsulated catalyst (Rh-HMS) was synthesized and characterized by PXRD, FT-IR, surface area measurements and TEM. The catalyst was effectively active with 99% conversion of propene and 100% selectivity to aldehydes. The effects of reaction parameters: temperature, partial pressure of CO and H2, amount of catalyst and HRh(CO)(PPh3)3 to TEOS ratio on conversion, selectivity and rates were investigated in detail. The rates determined in term of the formation of aldehydes were found to be first order with respect to hydrogen pressure. Catalyst showed first order dependence towards its lower amount. CO pressure variation showed positive order towards lower pressure and inhibition at higher pressures. The investigated mass transfer effects on the kinetics indicated that the reaction runs with negligible mass transfer limitations. The heterogenized Rh-HMS catalyst was effectively recycled for six times.
- Sudheesh,Parmar, Jaydeep N.,Shukla, Ram S.
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- Palladium-Catalyzed Oxidative N-Dealkylation/Carbonylation of Tertiary Amines with Alkynes to α,β-Alkynylamides
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The first highly effective Pd/C-catalyzed oxidative N-dealkylation/carbonylation of various aliphatic as well as cyclic tertiary amines with alkynes has been described. The selective sp3 C-N bond activation of tertiary amines at the less steric side using O2 as a sole oxidant and a plausible reaction pathway for the reaction are discussed. The general and operationally simple methodology provides an alternative for the synthesis of a wide range of alk-2-ynamide derivatives under mild conditions. The present protocol is ecofriendly and practical, and it shows significant recyclability.
- Mane, Rajendra S.,Bhanage, Bhalchandra M.
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- Two new fatty acid derivatives from the stem bark of alchornea laxiflora (euphorbiaceae)
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Euphorbiaceae is a family of plants used in traditional remedies in central Africa to treat selected diseases. Some of the phytochemical components in the stem bark of Alchornea laxiflora that have biochemical activity were identified. A number of novel compounds were isolated, including a new fatty acid ester, (1) a new ceramide, (2) some triterpenoids, (3-5), ellagic acid (6) and its derivatives (7, 8) were isolated. The structures of these compounds were determined on the basis of spectroscopic methods as well as HR-ESI-TOF-MS analysis, chemical transformation and by comparison of their physical and spectral data with those reported in the literature. The cytotoxicity of some isolated compounds was investigated against human promyelocytic leukaemia (HL60) cell line by using the MTT method. Compounds 1, 4 and 5 showed a cytotoxic activity with IC50 at 58.7, 6.6 and 6.8 μM, respectively.
- Sandjo, Louis Pergaud,Poumale, Hervé M. Poumale,Siwe, Xavier Noudou,Ntede, Hippolyte Nga,Shiono, Yoshihito,Ngadjui, Bonaventure Tchaleu,Krause, Rui M. W.,Ndinteh, Derek Tantoh,Mbafor, Joseph Tanyi
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- Copper(I) complexes with polymeric 2,2′-biquinoline-containing ligands as electrocatalysts for selective oxidation of the secondary hydroxy group in 3,24-dihydroxy-5β-cholane with oxygen
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Indirect electrocatalytic selective oxidation of the secondary hydroxy group in 3,24-dihydroxy-5β-cholane was performed using atmospheric oxygen in the presence of copper(I) complex with a polymeric 2,2′-biquinoline- containing ligand as catalyst. The reaction was characterized by a high yield (85%), 100% selectivity, and mild conditions, the CuII/CuI redox potential being -0.55 V relative to Ag/AgCl/KCl.
- Magdesieva,Dolganov,Latyshev,Yakimanskii,Goikhman,Podeshvo,Lukashev
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- Efficient strategy for interchangeable roles in a green and sustainable redox catalytic system: IL/PdII-decorated SBA-15 as a mesoporous nanocatalyst
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Time and again, SBA-15-based composites as mesoporous materials and the incorporation of transition metals in them have been attracting dramatic attention in the field of catalysis due to their remarkable features. In this paper, the activity of SBA-15 supported ionic liquid-Pd(ii) has been investigated in the catalytic transfer hydrogenation of nitroarenes with formic acid as a hydrogen donor at room temperature in water medium, and the oxidation of benzyl alcohols to benzaldehyde derivatives under atmospheric oxygen at high temperature. This novel nanocatalyst was characterized by FT-IR, SA-XRD, BET, BJH, TGA, FE-SEM, TEM, and ICP as the most commonplace techniques for analyzing its characteristics to be revealed as truth. Furthermore, the EDX analysis illustrates the grafting of the ionic liquid-Pd(ii) into SBA-15. The catalyst showed high stability under reaction conditions, and can be recovered and reused for at least 15 and 6 reaction runs in oxidation and reduction reactions, respectively.
- Sadeghi, Samira,Karimi, Meghdad,Radfar, Iman,Gavinehroudi, Reza Ghahremani,Saberi, Dariush,Heydari, Akbar
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- Synthesis and characterization of supported stabilized palladium nanoparticles for selective hydrogenation in water at low temperature
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Zirconia supported vacant phosphotungstate stabilized Pd nanoparticles (Pd-PW11/ZrO2) were prepared using a simple impregnation and post reduction method, characterized and their efficiency for selective C=C hydrogenation of unsaturated compounds explored. The establishment of a hydrogenation strategy at low temperature using water as solvent under mild conditions makes the present system environmentally benign and green. The catalyst shows outstanding activity (96% conversion) with just a small amount of Pd(0) (0.0034 mol%) with high substrate/catalyst ratio (29 177/1), TON (28 010) and TOF (14?005 h?1) for cyclohexene (as a model substrate) hydrogenation. The catalyst was recovered by simple centrifugation and reused for up to five catalytic cycles without alteration in its activity. The present catalyst was found to be viable towards different substrates with excellent activity and TON (18 000 to 28 800). A study on the effect of addenda atom shows that the efficiency of the catalyst can be enhanced greatly by increasing the number of counter protons. This challenging strategy would greatly benefit sustainable development in chemistry as it diminishes the use of organic solvents and offers economic and environmental benefits as water is cheap and non-toxic.
- Patel, Anish,Patel, Anjali
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- Photosensitized oxidative deprotection of oximes to their corresponding carbonyl compounds by platinum(II) terpyridyl acetylide complex
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Platinum(II) terpyridyl acetylide complex (1) photosensitizes the oxidation of aldoximes 2-4, aliphatic acyclic and cyclic ketoximes 5-7, and aromatic ketoximes 8-10 into their corresponding carbonyl compounds with good to excellent yields in acetonitrile solution. This deprotection of oximes proceeds via singlet oxygen (1O2) mechanism. The photosensitizer can be easily separated from the product and unreacted starting material by extraction with ethyl acetate and reused for photooxidation without loss of 1O2-generation capacity.
- Yang, Yue,Zhang, Dong,Wu, Li-Zhu,Chen, Bin,Zhang, Li-Ping,Tung, Chen-Ho
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- Compounds of chromium(VI): The pyridine-chromic anhydride complex, benzimidazolinium dichromate, and three 2-alkyl-1H-benzimidazolinium dichromates
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Pyridine, when allowed to react with chromic anhydride under strictly anhydrous conditions, gives the known, very air-sensitive, crystalline 2:1 Lewis acid-base complex 1. The crystal structure has now been successfully determined. When benzimidazole and three 2-alkyl-1H-benzimidazoles were treated with chromium trioxide in aqueous acetic acid, crystalline dichromate salts (2-5) were readily formed. These salts consist of dichromate anions linked to the cations by hydrogen bonds of the type N-H...O. The chromium atoms have distorted tetrahedral environments, with the Cr-O distances being typical for dichromate anions. In the cases of the 2-methyl and 2-ethyl salts, the anions are disordered about a centre of inversion. The hydrogen bonding arrangements are discussed and the structures are compared with other oxygenated chromium(VI) species. The dichromate salts are useful selective oxidants for a range of primary and secondary alcohols; examples of these reactions are reported.
- Cameron, T. Stanley,Clyburne, Jason A.C.,Dubey, Pramod K.,Grossert, J. Stuart,Ramaiah,Ramanatham,Sereda, Sergei V.
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- Selective oxidation of alcohols to aldehydes by hydrogen peroxide using hexamolybdochromate(III) as catalyst
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Anderson type hexamolybdochromate(III) was utilized as a catalyst for facile conversion of various aliphatic, benzylic and heterocyclic alcohols to corresponding aldehydes and ketones in good yields. The reaction was carried out in 50% aq. acetonitrile us
- Mardur,Gokavi
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- Sandwich type tri-palladium substituted phosphotungstate, [Pd3(PW9O34)2]11?: Synthesis, structural characterization and catalytic evaluation
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The present work showcases, first time, the synthesis of tri-palladium substituted sandwich type phosphotungstate, [Pd3(PW9O34)2]11?, from its individual salts in super acidic medium as well as the single crystal structure of the same. Further, various spectral analysis carried out to support the crystal data. A preliminary study for the hydrogenation of nitrobenzene has been carried out to evaluate the catalytic activity of the complex.
- Patel, Anish,Patel, Anjali,Sadasivan, Rajesh
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- Cyclometalation of 1-Aza 1,3-Dienes in reactions with Ru3(CO)12 with formation of four- and five-membered azaruthenacycles
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The dinuclear compounds Ru2(CO)6[R1CH2CC(H)NR2] (2a-e) and Ru2(CO)6[R1C=C(H)CH2NR2] (3a,b,d) are the first isolable products during thermal reactions of Ru3(CO)12 with 1-aza 1,3-dienes R1C(H)=C-(H)C(H)=NR2(R1,R2-MAD; R1, R2 = CH3, i-Pr (1a), CH3, c-Hex (1b), CH3, t-Bu (1c), C6H5, i-Pr (1d), C6H5, T-Bu (1e)). Both primary products 2 and 3 contain an isomerized MAD ligand that is part of a four-(2) or five-membered (3) azaruthenacycle. The molecular structure of 3a has been solved by X-ray crystallography: space group P1?, with a = 22.511 (4) ?, b = 13.740 (3) ?, c = 12.443 (2) ?, α = 103.21 (1)?, β = 113.00 (1)?, γ = 77.71 (1)?, V = 851.3 ?, Z = 2, and R = 0.027 (Rw = 0.042), for 2540 observed reflections. Compound 3a contains a formally 6-electron donating enyl-amido ligand and is μ-N,-σ-Cβη2-C=C-coordinated to a sawhorse Ru2(CO)6 core. In solution both 2 and 3 are stereochemically nonrigid, due to windshield wiper motions of the asymmetrically bridged amido ligands. This process is more facile for 2 (ΔG? ≈ 35 kJ mol-1) than for 3 (ΔG? 62 kJ mol-1), and the ΔG? value for 3 was shown to be independent of the R1 and R2 substituents. In refluxing heptane 2 and 3 are converted into the linear 66-electron cluster Ru4(CO)10[R1C=C(H)C(H)=NR2] 2 (5a-e), albeit conversion of 2 into 5 proceeded very slowly and incompletely. Conversion of 3 into 5 proceeds via the intermediacy of (μ-H)Ru2(CO)5[R1C= C(H)C(H)=NR2] (4), which air-sensitive compound could be observed and isolated for R1, R2 = C6H5, i-Pr (4d). Reaction of 3a,b with CH,R2-MAD or crotonaldehyde in heptane at 90°C results in the formation Of Ru2(CO)6[CH2CC(H)C(H)=NR2] (6a,b). During this conversion the coordinated ligand is dehydrogenated whereas the added substrate acts as a hydrogen acceptor. For crotonaldehyde it was shown that the olefin moiety was hydrogenated chemoselectively. The formation of 2 and 3 out of Ru3(CO)12 and R1,R2-MAD and their conversion into 4-6 are discussed.
- Mul, Wilhelmus P.,Elsevier, Cornelis J.,Polm, Louis H.,Vrieze, Kees,Zoutberg, Martin C.,Heijdenrijk, Dick,Stam, Casper H.
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- Preparation and Application of Palladium Nanoparticle Impregnated Chloromethylated Polysulfone Matrix as an Efficient Catalytic Membrane for Oxidation of Alcohols
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The use of palladium nanoparticles embedded in a chloromethylated Polysulfone (CMPSf) matrix was developed for highly efficient oxidation of primary and secondary alcohols to corresponding aldehyde and ketone in organic solvent free condition. Pd (Π)/bis (2, 4-dihydroxybenzaldehyde) chelate chemically incorporated onto CMPSf was used to prepare beneficial catalytic membranes. Chemical structure and thermal properties of resulting membranes were characterized via FTIR, 1HNMR, UV-vis, TGA and DSC techniques. Morphology and particle distribution throughout the catalytic membranes was elucidated using FE-SEM. An average particle size of Pd nanoparticles was estimated about 20 nm by XRD technique. ICP technique proved that no Pd particles were leached out of the membrane into the solutions; hence the as-prepared catalytic membranes could be used several times without significant loss in their activities. This is in good accordance with formation of chemical bond between Pd and polymer matrix.
- Mahdavi, Hossein,Fayyazi, Faeze
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- Selective Hydrogenation of Unsaturated Carbonyl Compounds over an Oxidized Gold-Zirconium Alloy
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An oxidized amorphous Au-Zr alloy showed high selectivities for partial hydrogenation of unsaturated carbonyl compounds to unsaturated alcohols, contrasting with their low catalytic activity in the hydrogenation of unsaturated to saturated alcohols; the active sites of this catalyst are modified gold rather than impurities since the amounts of impurities present were too small (80 p.p.m.) to show hydrogenation activity.
- Shibata, M.,Kawata, N.,Masumoto, T.,Kimura, H.
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- Solvent-free chemoselective oxidation of alcohols by hydrogen peroxide using a new synthesized copper complex as reusable heterogeneous nanocatalyst
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Single crystal of a new copper(II) Schiff base complex [Cu(HL)(H2O)NO3] (1) (H2L?=?{2-[(2-hydroxy-1,1-dimethyl-ethylimino)methyl]phenol}) and its nanostructure have been synthesized by slow evaporation of a methanol soluti
- Saeednia,Hatefi Ardakani,Pakdin-Parizi,Iranmanesh,Sinaei
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- A non-noble amorphous Co-Fe-B catalyst highly selective in liquid phase hydrogenation of crotonaldehyde to crotyl alcohol
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A nanosized amorphous Co-Fe-B catalyst exhibited higher selectivity and yield to crotyl alcohol than noble Pt-based catalysts in the hydrogenation of crotonaldehyde and could be prepared by a facile chemical reduction method. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
- Pei, Yan,Wang, Jianqiang,Fu, Qiang,Guo, Pingjun,Qiao, Minghua,Yan, Shirun,Fan, Kangnian
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- In situ synthesis of gold nanoparticles inside the pores of MCM-48 in supercritical carbon dioxide and its catalytic application
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Gold nanoparticles are deposited into the channels of MCM-48 through a simple H2-assisted reduction of HAuCl4 (aqueous solution) in supercritical carbon dioxide medium at 70 °C within 2-4 h. The nanoparticles were characterized by powder X-ray diffraction (PXRD), N 2 adsorption-desorption, transmission electron microscopy (TEM), and UV-Vis spectroscopy. The particle size of the synthesized material is tunable with the pressure (density) of the supercritical carbon dioxide medium. At the fixed temperature (70°C) and hydrogen pressure [P(H2) = 2 MPa], the Au particle size varies from ca. 25 nm to ca. 2 nm with the change in CO2 pressure from 7 MPa to 17 MPa. At the low solvent density conditions, larger particles of ~25 nm were obtained. On the contrary, a high solvent density of CO2 slows down particle aggregation, resulting in the small particle size within the range of 2-5 nm. This change in particle size with CO2 pressure and the interaction of the particles with the silica support were correlated well with long-range van der Waals interactions and consequently the Hamaker constant for the gold nanoparticle-CO2 (A131) and silica-gold core-CO 2 (A132), respectively. Supercritical carbon dioxide alone can provide a unique environment for stabilizing gold nanoparticles in the channels of the cubic mesoporous MCM-48 support and exquisite control of the particle size without perturbing the support structure. The synthesized material is highly stable, recyclable and no metal nanoparticle leaching was observed. The selective hydrogenation of crotonaldehyde with the synthesized material provides convincing evidence that the particles are inside the pores and available to the reactant molecules.
- Chatterjee,Ikushima,Hakuta,Kawanami
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- Peroxidative catalytic oxidation of alcohols catalyzed by heterobinuclear vanadium(V) complexes using H2O2 as terminal oxidizing agents
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Here we report the catalytic oxidation of benzylic alcohol, hetero-aryl alcohols and propargylic alcohols to their corresponding carbonyl compound using heterobimetallic sodium-dioxidovanadium(V) complexes. The present catalytic oxidation studies proceed at 70?°C using H2O2 as terminal oxidant. During the whole process, the complexes react with hydrogen peroxide to form peroxo-vanadium(V) species. The present study shows the heterogeneity of pre-catalyst which could be easily recovered and moreover isolation of product is very simple.
- Kurbah, Sunshine D.,Asthana,Syiemlieh, Ibanphylla,Lal, Ram A.
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- Kinetics and mechanism of catalytic oxidation of alcohols to carbonyl compounds with dioxygen in the Pd-containing aqua system
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The oxidation of lower aliphatic alcohols C1-C4 with dioxygen to form the corresponding carbonyl compounds in the presence of the PdII tetraaqua complexes and FeII-FeIII aqua ions in an aqueous medium was studie
- Potekhin
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- Understanding Anionic ligandless Palladium Species in the Mizoroki-Heck Reaction
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The anionic complex [NBu4][Pd(DMSO)Cl3], as a ligandless system, was shown to be an active catalyst in the Mizoroki-Heck coupling of aryl chlorides in the absence of strongly σ-donating ligands. To investigate the experimentally observed influence of halides and the amount of water on the catalytic activity, we employed a combination of experiments and theoretical calculations. The presence of water was shown to be critical for the formation of the active palladium(0) species by oxidation of in situ generated tributylamine. Oxidative addition to an anionic palladium(0) species was found to be the rate-determining step of the catalytic cycle. For the ensuing steps, both neutral and anionic pathways were considered. It was shown that, in the absence of strongly σ-donating neutral ligands, chloride ions stabilize the catalytic intermediates. Therefore, an anionic pathway is preferred, which explains the need for tetrabutylammonium chloride as an additive. The study of the influence of bromide ions on the catalytic activity revealed that the strongly exergonic displacement of the neutral substrates by bromide ions lowers the catalytic activity.
- Schroeter, Felix,Strassner, Thomas
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- Effect of reduction temperature on selective hydrogenation of crotonaldehyde over Ir/TiO2 catalysts
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Vapor-phase selective hydrogenation of crotonaldehyde was conducted over Ir/TiO2 catalysts to investigate the effect of reduction temperature on the catalytic behaviors. The catalyst reduced at 100 °C contained large amount of strong Lewis acid
- Chen, Ping,Lu, Ji-Qing,Xie, Guan-Qun,Hu, Geng-Shen,Zhu, Lin,Luo, Liang-Feng,Huang, Wei-Xin,Luo, Meng-Fei
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- Improved chemoselective hydrogenation of crotonaldehyde over bimetallic AuAg/SBA-15 catalyst
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Bimetallic AuAg/SBA-15 catalysts were disclosed to efficiently catalyze vapor-phase chemoselective hydrogenation of crotonaldehyde (CRAL) with improved hydrogenation rate and selectivity to crotonyl alcohol (CROL). The CRAL hydrogenation rate and product
- Lin, Haiqiang,Zheng, Jianwei,Zheng, Xinlei,Gu, Zhengqiang,Yuan, Youzhu,Yang, Yanhui
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- Rhodium Pyrrolylphosphine Complexes as Highly Active and Selective Catalysts for Propene Hydroformylation: The Effect of Water and Aldehyde on the Reaction Regioselectivity
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The hydroformylation of propene catalyzed by Rh(acac)(CO)2 (acac=acetylacetonate) with a 13-fold excess of N-pyrrolylphosphine ligands PPyr3, PPh2Pyr, or PPh(Pyr)2 (Pyr=NC4H4) was investigated under a pressure of 15 bar (propene/H2/CO=5:5:5) at 80 °C. The N-pyrrolylphosphine ligands facilitated an excellent regioselectivity towards n-butanal aldehyde, significantly better than PPh3 and PCy3 under the same conditions. In the presence of the strongest π-acceptor, PPyr3, the linear-to-branched aldehyde (l/b) ratio was 8.6, which increased to 27.1 if water was added to the system. The application of a pure aldehyde as a solvent instead of toluene caused a significant increase in the aldehyde yield but with a decreased l/b ratio (2.9–7.6). The regioselectivity parameter l/b increased to 19.3 after the introduction of water as a cosolvent.
- Mieczyńska, Ewa,Grzybek, Ryzard,Trzeciak, Anna M.
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- The kinetics of gas-phase propene hydroformylation over a supported ionic liquid-phase (SILP) rhodium catalyst
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An investigation of the kinetics of propene hydroformylation in the gas phase has been conducted over a silica-supported Rh-sulfoxantphos complex stabilized by the ionic liquid [bmim][OctSO4]. The reaction temperature was found to have a strong effect on the kinetics of n- and iso-butanal formation. For both products, it was observed that increasing the temperature decreased the apparent activation energy, altered the reaction orders with respect to reactants, and decreased the molar ratio of n- to iso-butanal. The observed changes in the kinetics are discussed in terms of the generally accepted mechanism for olefin hydroformylation and are attributed to a change in the rate-determining step (RDS). It is concluded that at low temperature, the RDS is alkene insertion into an Rh-H bond but becomes the oxidative addition of H2 at high temperature. The change in the RDS is rationalized in terms of a change in the elementary step with the largest Gibbs free energy of activation (ΔG?). A greater loss in entropy for the oxidative addition of H2 over alkene insertion causes the ΔG? of the oxidative addition to be greater than the ΔG? of alkene insertion at high temperature.
- Hanna, David G.,Shylesh, Sankaranarayanapilla,Werner, Sebastian,Bell, Alexis T.
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- Preparation of SiO2-encapsulated SnPt nanoparticle catalysts for selective hydrogenation of unsaturated aldehyde
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The SiO2-encapsulated SnPt catalysts having the core-shell structures were prepared by using the polyol process. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) results indicated the SnPt alloy nanoparticles were covered with a thin silica layer with the porous structures. The SiO2-encapsulated SnPt catalysts showed the higher selectivity of crotyl alcohol for selective hydrogenation of crotonaldehyde in comparison with the Sn-Pt/SiO2 catalysts prepared by a conventional co-impregnation. It was considered that the formation of uniform SnPt alloy phases and the pore structures in the silica layers with the steric hindrance would enhance the chemo-selective hydrogenation of crotonaldehyde.
- Taniya, Keita,Yu, Chih Hao,Tsang, Shik Chi,Ichihashi, Yuichi,Nishiyama, Satoru
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- 1-Hydroxy-1-methylethylphosphinates intermediates for the synthesis of functional phosphorus acids
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A base-labile protecting group for hydrogen connected to phosphorus has been found. This has led to the development of hypophosphorus acid synthons.
- Baylis, E. Keith
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- Dibal-H reduction of methyl butyrate into butyraldehyde using microreactors
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The reduction of methyl butyrate into butyraldehyde with Dibal-H in inicroreactors is described. Running the reaction continuously in a microreactor afforded results similar to those of batch experiments, but very low temperatures are not necessary and the reaction may be scaled-up without selectivity decrease. Different microreaetors were used, and their mixing performances were compared. Increasing the reaction concentration and thus the throughput showed that even when working with microreactors, heat management should not be underestimated. Multi-injection was tested as a way to better control the temperature at the mixing point(s).
- Ducry, Laurent,Roberge, Dominique M.
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- Influence of calcination temperatures on iridium dispersion and hydrogenation activity in silica-supported iridium catalysts
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The influence of calcination temperatures on the dispersion of Ir/SiO 2 catalysts has been studied. At lowcalcination temperatures, the chloride precursor was dispersed on the silica surface and formed highly dispersed Ir/SiO2 cataly
- Shibuya, Ryoji,Ohshima, Masa-Aki,Kurokawa, Hideki,Miura, Hiroshi
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- Identification of an unexpected peroxide formed by successive isomerization reactions of the n-butoxy radical in oxygen
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A previously unreported peroxide, C4H8O3 (5), has been identified and its mechanism of formation proposed. It is generated by two successive isomerization reactions of n-C4H9O radicals in O2. These radicals are produced by di-n-C4H9O-OC4H9 pyrolysis at 480 K in a wall-passivated quartz vessel. The peroxide is collected, among other end-products, on a liquid-nitrogen trap and recovered in liquid acetonitrile. Analysis was carried out by GC-MS, GC-MS-MS [electron impact (EI) and NH3 (or ND3)-chemical ionization (CI) conditions] and GC-FTIR. After micropreparative GC separation of the titled peroxide, 1H NMR and high-resolution EIMS were also obtained. The compound was identified as 3α-hydroxy-1,2-dioxane. The hydroperoxybutyraldehyde OHC-(CH2)2-CH2O2H is proposed to be initially formed in the gas phase and to be in equilibrium with its cyclic form (six-membered ring peroxide), by far predominant in the liquid phase at room temperature. The implications of this hydroperoxybutyraldehyde in atmospheric pollution (due to the peroxide producing capability of radicals) and in combustion are discussed.
- Jorand, Francois,Heiss, Adolphe,Sahetchian, Krikor,Kerhoas, Lucien,Einhorn, Jacques
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- Catalytic hydrogenation of crotonaldehyde and oxidation of benzene over active and recyclable palladium nanoparticles stabilized by polyethylene glycol
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Polyethylene glycol (PEG)-stabilized Palladium (Pd) nanoparticles have been successfully synthesized by a simple hydrothermal approach. The as-prepared catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption-desorption measurements. Pd nanoparticles show a high degree of dispersion in PEG with a small average particle size distribution in the range of 3-6 nm. The Pd/PEG catalyst exhibited a remarkable catalytic activity toward selective hydrogenation of crotonaldehyde and oxidation of benzene in liquid phase under mild conditions. The catalyst could be easily removed from the reaction mixture and its recyclability was possible for ten times for crotonaldehyde and two times for benzene. The catalytic performance was found to depend essentially on the catalyst and target concentrations and reaction time.
- Harraz,El-Hout,Killa,Ibrahim
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- Promoted chemoselective crotonaldehyde hydrogenation on zirconia-doped SiO2 supported Ag catalysts: Interfacial catalysis over ternary Ag–ZrO2–SiO2 interfaces
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In gas-phase chemoselective hydrogenation of crotonaldehyde on Ag-based catalysts, zirconia doping on silica supports was found to improve catalytic performance in terms of unsaturated alcohol selectivity, hydrogenation activity, and stability. The surface modification of silica by zirconia doping favors the fine dispersion of Ag species due to the enhanced quantity and strength of surface acid sites, which enable construction of abundant catalytic sites effective for C[dbnd]O bond hydrogenation. High crotyl alcohol selectivity, exceeding 80%, and significant inhibition of monohydrogenation on the C[dbnd]C bond were observed on the optimal Ag/Zr–SiO2 catalyst. Dynamic O2 chemisorption measurement revealed that the pure Ag powders did not chemisorb O2 irreversibly under 323 K, but SiO2 or Zr–SiO2 supported Ag catalysts did. The amounts of Ag active for O2 chemisorption, which are at least one order of magnitude lower than that of surface Ag derived from TEM and XRD characterizations, match well with the perimeter interface Ag of hemispherical particles. A strong correlation between hydrogenation activity and O2 uptake on those Ag/SiO2 and Ag/Zr–SiO2 catalysts with different Ag dispersions and deactivation degrees was observed, implying that the effective catalytic sites for crotonaldehyde chemoselective hydrogenation may originate from accessible interface sites with unique redox properties. Catalyst induction and deactivation were observed on both Ag/SiO2 and Ag/Zr–SiO2 catalysts in real catalytic operation. Changes in metal stable interface structure, rather than metal aggregation and coagulation, are assumed to be the main cause of irreversible catalyst deactivation, because the apparent Ag particle sizes changed slightly, but the oxygen chemisorption ability deteriorated considerably. Electropositive Ag sites interacting with neighboring oxygen from oxide supports at the ternary Ag–ZrO2–SiO2 interface are proposed to account for highly selective C[dbnd]O bond hydrogenation to produce the desired unsaturated alcohol.
- Lin, Haiqiang,Qu, Hongyan,Chen, Weikun,Xu, Kang,Zheng, Jianwei,Duan, Xinping,Zhai, Hesheng,Yuan, Youzhu
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- Solvent-free selective oxidation of alcohols with tert-butyl hydroperoxide catalyzed by palladium(II) isatin Schiff base complex supported into three-dimensional mesoporous silica KIT-6
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In this work, the catalytic activity of a palladium(II) isatin Schiff base complex immobilized into mesoporous silica KIT-6 (Pd-isatin Schiff base@KIT-6) was studied for the oxidation of different alcohols with tert-butyl hydroperoxide (TBHP, 70% aqueous solution) as an oxidant under solvent-free conditions. To find the suitable reaction conditions, the effect of essential factors including the solvent, temperature, catalyst amount and kind of oxidant on the oxidation of benzyl alcohol was explored. The results showed that in this catalytic system, the corresponding aldehydes and ketones were obtained with high to excellent yields at 50?°C without the formation of carboxylic acids as by-products. The catalyst was easily recovered by simple filtration and reused in five subsequent reaction cycles without any significant loss in the catalytic activity. Moreover, the comparison of the Fourier transform infrared (FT-IR) spectrum, X-ray diffraction (XRD) pattern, scanning and transmission electron microscopy (SEM and TEM) images of the used catalyst with a fresh one showed that the structure of the Pd-isatin Schiff base@KIT-6 catalyst remained intact after five times of reuse.
- Mousavi, Davoud,Ardakani, Mehdi Hatefi,Saeednia, Samira,Sabet, Mohammad
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- Highly efficient and chemoselective hydrogenation of α,β-unsaturated carbonyls over Pd/N-doped hierarchically porous carbon
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Palladium nanoparticles supported on N-doped hierarchically porous carbon, Pd/CNx, has been developed as a highly efficient, reusable and environmentally benign heterogeneous catalyst for the selective hydrogenation of various α,β-unsaturated carbonyls to their corresponding saturated carbonyls under mild conditions (303 K, 1 bar H2). Complete conversion of a series of α,β-unsaturated carbonyls was achieved with excellent selectivity (>99%) within 4 h. Moreover, the catalyst can be easily recovered by centrifugation and withstands recycling up to 8 times without apparent loss of activity and selectivity. The considerable catalytic performance is attributed to the hierarchically porous network and incorporation of nitrogen atoms. This catalytic system opens up an efficient, selective, recyclable and sustainable method for selective hydrogenation.
- Wei, Zhongzhe,Gong, Yutong,Xiong, Tianyi,Zhang, Pengfei,Li, Haoran,Wang, Yong
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- Influence of Zn on the characteristics and catalytic behavior of TiO 2-supported Pt catalysts
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Vapor-phase hydrogenation of toluene and selective hydrogenation of crotonaldehyde have been performed over Pt/TiO2 and PtZn/TiO 2 after low (473 K) and high (773 K) temperature reduction. The catalysts were characterized by H2
- Silvestre-Albero,Sepulveda-Escribano,Rodriguez-Reinoso,Anderson
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- Synthesis, characterization, electrochemical, catalytic and antimicrobial activity studies of hydrazone Schiff base ruthenium(II) complexes
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Four tridentate O, N, O donor Schiff base ligands were prepared by the reaction of substituted benzhydrazide and appropriate salicylaldehyde. Thecomplexesof these ligandswere synthesizedby refluxingtheligands with ruthenium(II) starting complexes of the formula [RuHCl(CO)(EPh3) 2B] in benzene, where E = P or As; B = PPh3 or AsPh 3 or pyridine. The newly synthesized complexes were characterized by elemental, spectral (FT-IR, UV and NMR) and electrochemical data. On the basis of the above studies, an octahedral structure has been proposed for all the complexes. The catalytic efficiency of the complexes in aryl-aryl couplings and oxidation of alcohols was examined and their inhibition activity against the growth of themicro-organisms was also examined. Copyright
- Thilagavathi,Manimaran,Priya, N. Padma,Sathya,Jayabalakrishnan
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- Anti-Markovnikov hydration of alkenes over platinum-loaded titanium oxide photocatalyst
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Hydration of various alkenes proceeded over a platinum-loaded titanium oxide photocatalyst. It is notable that, unlike conventional acid-catalysts, the photocatalyst preferentially promoted the hydration according to the anti-Markovnikov rule. The results of some reaction experiments and semiempirical molecular orbital calculations suggested the reaction path of this hydration as follows: an electrophilic surface oxygen radical species formed on the photoexcited titanium oxide attacks a carbon double bond of the alkene to produce an intermediate, followed by the addition of a hydrogen radical formed on the platinum sites to produce an alcohol. The anti-Markovnikov selectivity for each investigated alkene would be determined by the stability of the radical intermediate.
- Yuzawa, Hayato,Yoneyama, Shoko,Yamamoto, Akihito,Aoki, Masanori,Otake, Kazuko,Itoh, Hideaki,Yoshida, Hisao
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- Fluid phase equilibria of the reaction mixture during the selective hydrogenation of 2-butenal in dense carbon dioxide
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Knowledge of the phase behaviour and composition is of paramount importance for understanding multiphase reactions. We have investigated the effect of the phase behaviour in the palladium-catalysed selective hydrogenation of 2-butenal to saturated butanal in dense carbon dioxide. The reactions were performed using a 5 wt% Pd on activated carbon in custom-designed high pressure autoclaves at 323 K. The Cubic-Plus-Association (CPA) equation of state was employed to model the phase behaviour of the experimentally studied systems. CPA binary interaction parameters were estimated based on the experimental vapour-liquid or liquid-liquid equilibria data available in the literature. No experimental data for the CO2-2-butenal binary system were available in the literature; therefore, the bubble points of this mixture of varying composition at three different temperatures were measured in a high-pressure view cell. The results of the catalytic experiments showed that small amounts of carbon dioxide added to the system significantly decrease the conversion, whereas at higher loadings of CO2 the reaction rate gradually increases reaching a maximum. The CPA calculations revealed that this maximum is achieved in the so-called "expanded liquid" region, which is located near the critical point of the reacting mixture. It was also found that in this point the hydrogen concentration achieved its maximum in the CO2-expanded phase. Furthermore, the pressure - temperature regions where the multicomponent reaction system exists in one single phase and in multiphase were calculated.
- Musko, Nikolai E.,Jensen, Anker Degn,Baiker, Alfons,Kontogeorgis, Georgios M.,Grunwaldt, Jan-Dierk
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- High regioselectivity in propylene hydroformylation using rhodium-bisphosphite catalysts is due to properties of the SRS diastereomer
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The large cone angle and bite angle of the SRS ligand diastereomer in biphenol-based Rh-bisphosphite catalysts lead to high linear regioselectivity in the hydroformylation of propylene.
- Briggs,Whiteker
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- Ru-Ti intermetallic catalysts for the selective hydrogenation of crotonaldehyde
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Titanium-doped ruthenium catalysts were prepared, characterized, and studied in the vapor-phase selective hydrogenation of crotonaldehyde. The catalysts were prepared by co-impregnation and by the chemical vapor deposition (CVD) method. XPS results indicate that titanium was well dispersed on the support for the catalyst prepared by CVD. Ruthenium dispersion was diminished by titanium addition, and a strong interaction of ruthenium with titanium was deduced from CO adsorption microcalorimetry. Results obtained in the vapor-phase hydrogenation of crotonaldehyde showed that the monometallic Ru catalyst had no selectivity toward crotyl alcohol, whereas the RuTi catalyst prepared by the CVD method gave the highest selectivity.
- Ruiz-Martinez,Fukui,Komatsu,Sepulveda-Escribano
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- Aldehydes via Palladium Catalysed Reductive Carbonylation of Esters
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Aldehydes are obtained in high selectively via the low pressure, palladium catalysed reaction of esters and synthesis gas (CO-H2).
- Graff, James L.,Romanelli, Michael G.
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- ALDEHYDE GENERATION VIA ALKENE HYDROFORMYLATION
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Aldehyde generation includes providing a first input stream, a second input, and an alkene substrate to a reactor system. The first input stream includes a catalyst, a ligand, and an organic solvent. The second input stream includes a mixture of carbon monoxide (CO) and hydrogen gas (H2). The alkene substrate is in either gaseous form or liquid form, the liquid form of the alkene substrate being provided with the first input stream, the gaseous form of the alkene substrate being provided with the second input stream. The reactor system includes a first reactor and a second reactor, where the second reactor is gas permeable and positioned within the first reactor.
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Paragraph 0083; 0084
(2021/09/26)
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- Catalyst composition for hydroformylation and method of preparing aldehyde using the same
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The present invention relates to a catalyst composition for hydroformylation and a method of preparing an aldehyde using the same. More specifically, the present invention provides a catalyst composition for hydroformylation including a specific phosphite-based ligand and a transition metal compound in a specific amount range, thereby being capable of greatly lowering a use amount of an expensive transition metal compound and exhibiting excellent catalyst activity or stability. In addition, by using the catalyst composition in hydroformylation, excellent reaction efficiency may be provided and iso-aldehyde may be generated in high yield.
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Page/Page column 8-10
(2021/12/02)
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- Reactive Species and Reaction Pathways for the Oxidative Cleavage of 4-Octene and Oleic Acid with H2O2over Tungsten Oxide Catalysts
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Oxidative cleavage of carbon-carbon double bonds (C-C) in alkenes and fatty acids produces aldehydes and acids valued as chemical intermediates. Solid tungsten oxide catalysts are low cost, nontoxic, and selective for the oxidative cleavage of C-C bonds with hydrogen peroxide (H2O2) and are, therefore, a promising option for continuous processes. Despite the relevance of these materials, the elementary steps involved and their sensitivity to the form of W sites present on surfaces have not been described. Here, we combine in situ spectroscopy and rate measurements to identify significant steps in the reaction and the reactive species present on the catalysts and examine differences between the kinetics of this reaction on isolated W atoms grafted to alumina and on those exposed on crystalline WO3 nanoparticles. Raman spectroscopy shows that W-peroxo complexes (W-(η2-O2)) formed from H2O2 react with alkenes in a kinetically relevant step to produce epoxides, which undergo hydrolysis at protic surface sites. Subsequently, the CH3CN solvent deprotonates diols to form alpha-hydroxy ketones that react to form aldehydes and water following nucleophilic attack of H2O2. Turnover rates for oxidative cleavage, determined by in situ site titrations, on WOx-Al2O3 are 75% greater than those on WO3 at standard conditions. These differences reflect the activation enthalpies (ΔH?) for the oxidative cleavage of 4-octene that are much lower than those for the isolated WOx sites (36 ± 3 and 60 ± 6 kJ·mol-1 for WOx-Al2O3 and WO3, respectively) and correlate strongly with the difference between the enthalpies of adsorption for epoxyoctane (ΔHads,epox), which resembles the transition state for epoxidation. The WOx-Al2O3 catalysts mediate oxidative cleavage of oleic acid with H2O2 following a mechanism comparable to that for the oxidative cleavage of 4-octene. The WO3 materials, however, form only the epoxide and do not cleave the C-C bond or produce aldehydes and acids. These differences reflect the distinct site requirements for these reaction pathways and indicate that acid sites required for diol formation are strongly inhibited by oleic acids and epoxides on WO3 whereas the Al2O3 support provides sites competent for this reaction and increase the yield of the oxidative cleavage products.
- Yun, Danim,Ayla, E. Zeynep,Bregante, Daniel T.,Flaherty, David W.
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p. 3137 - 3152
(2021/04/06)
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- Synergistic Catalytic?Effect?of N-Hydroxyphthalimide/Cobalt Tetraamide Phthalocyanine and Its Application for Aerobic Oxidation of Hydrocarbons and Alcohols
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Abstract: The activation of oxygen?for?selective?oxidation?of?organic molecules, such as hydrocarbons and alcohols, remains a major catalytic?challenge. We have developed a catalytic system combining N-hydroxyphthalimide (NHPI) with cobalt tetraamide phthalocyanine [CoPc(CONH2)4] for the oxidation of hydrocarbons and alcohols at 75?°C under an oxygen atmosphere. CoPc(CONH2)4 was synthesized by trimellitic anhydride-urea method, and its structure was confirmed by FT-IR, UV–Vis and XRD. This catalyst, in synergy with NHPI/O2 system, exhibited excellent catalytic ability and high selectivity in the oxidation of hydrocarbons and alcohols. Based on the experimental results, a reasonable reaction mechanism was proposed for the oxidation of alkanes and alcohols, respectively. Graphic Abstract: Cobalt tetraamide phthalocyanine (CoPc(CONH2)4) was synthesized by a simple solid-thermal method, and the synergistic catalysis oxidation of NHPI and CoPc(CONH2)4 was studied. A synergistic catalysis system for the aerobic oxidation of hydrocarbons and alcohols by N-hydroxyphthalimide combined with cobalt tetraamide phthalocyanine has been developed.[Figure not available: see fulltext.]
- Li, Fei,Tang, Shuo,Tang, Zhilin,Ye, Lingjun,Li, Hehua,Niu, Fanfan,Sun, Xiaoling
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- Green, homogeneous oxidation of alcohols by dimeric copper(II) complexes
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Three pyrazole derivatives, 3,5-dimethyl-1H-pyrazole (DMPz) (I), 3-methyl-5-phenyl-1H-pyrazole (MPPz) (II), and 3,5-diphenyl-1H-pyrazole (DPPz) (III), were prepared via reacting semicarbazide hydrochloride with the acetylacetone, 1-phenylbutane-1,3-dione, and 1,3-diphenylpropane-1,3-dione, respectively. Complexes 1–3 were isolated by reacting CuCl2·2H2O with I–III, respectively, and characterized by CHNS elemental analyses, FT-IR, UV-Vis, 1H and 13C NMR, EPR spectra, and TGA/DTA. Molecular structures of the pyrazole derivatives I–III and copper(II) complexes 2 and 3 were studied through single-crystal XRD analysis to confirm their molecular structures. Overlapping of hyperfine splitting in the EPR spectra of the dimeric copper(II) complexes 1–3 indicates that both copper centers do not possess the same electronic environment in solution. The copper(II) complexes are dimeric in solid state as well as in solution and catalyze the oxidation of various primary and secondary alcohols selectively. Catalysts 1–3 show more than 92% product selectivity toward ketones during the oxidation of secondary alcohols. Surprisingly primary alcohols, which are relatively difficult to oxidize, produce carboxylic acid as a major product (48%–90% selectivity) irrespective of catalytic systems. The selectivity for carboxylic acid rises with decreasing the carbon chain length of the alcohols. An eco-friendly and affordable catalytic system for oxidation of alcohols is developed by the utilization of H2O2, a green oxidant, and water, a clean and greener solvent, which is a notable aspect of the study.
- Maurya, Abhishek,Haldar, Chanchal
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p. 885 - 904
(2020/12/18)
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- Dual utility of a single diphosphine-ruthenium complex: A precursor for new complexes and, a pre-catalyst for transfer-hydrogenation and Oppenauer oxidation
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The diphosphine-ruthenium complex, [Ru(dppbz)(CO)2Cl2] (dppbz = 1,2-bis(diphenylphosphino)benzene), where the two carbonyls are mutually cis and the two chlorides are trans, has been found to serve as an efficient precursor for the synthesis of new complexes. In [Ru(dppbz)(CO)2Cl2] one of the two carbonyls undergoes facile displacement by neutral monodentate ligands (L) to afford complexes of the type [Ru(dppbz)(CO)(L)Cl2] (L = acetonitrile, 4-picoline and dimethyl sulfoxide). Both the carbonyls in [Ru(dppbz)(CO)2Cl2] are displaced on reaction with another equivalent of dppbz to afford [Ru(dppbz)2Cl2]. The two carbonyls and the two chlorides in [Ru(dppbz)(CO)2Cl2] could be displaced together by chelating mono-anionic bidentate ligands, viz. anions derived from 8-hydroxyquinoline (Hq) and 2-picolinic acid (Hpic) via loss of a proton, to afford the mixed-tris complexes [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], respectively. The molecular structures of four selected complexes, viz. [Ru(dppbz)(CO)(dmso)Cl2], [Ru(dppbz)2Cl2], [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], have been determined by X-ray crystallography. In dichloromethane solution, all the complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the complexes shows redox responses within 0.71 to -1.24 V vs. SCE. [Ru(dppbz)(CO)2Cl2] has been found to serve as an excellent pre-catalyst for catalytic transfer-hydrogenation and Oppenauer oxidation.
- Mukherjee, Aparajita,Bhattacharya, Samaresh
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p. 15617 - 15631
(2021/05/19)
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- A TEMPO-Functionalized Ordered Mesoporous Polymer as a Highly Active and Reusable Organocatalyst
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The properties of high stability, periodic porosity, and tunable nature of ordered mesoporous polymers make these materials ideal catalytic nanoreactors. However, their application in organocatalysis has been rarely explored. We report herein for the first time the incorporation of a versatile organocatalyst, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), into the pores of an FDU-type mesoporous polymer via a pore surface engineering strategy. The resulting FDU-15-TEMPO possesses a highly ordered mesoporous organic framework and enhanced stability, and shows excellent catalytic activity in the selective oxidation of alcohols and aerobic oxidative synthesis of 2-substituted benzoxazoles, benzimidazoles and benzothiazoles. Moreover, the catalyst can be easily recovered and reused for up to 7 consecutive cycles.
- Guo, Ying,Wang, Wei David,Li, Shengyu,Zhu, Yin,Wang, Xiaoyu,Liu, Xiao,Zhang, Yuan
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supporting information
p. 3689 - 3694
(2021/09/29)
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- Catalytic study of the copper-based magnetic nanocatalyst on the aerobic oxidation of alcohols in water
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A copper-based magnetic nanocatalyst has been prepared by co-precipitation method and characterized by FESEM, EDS, TEM, XRD, XRF, ICP–OES, FTIR, and BET analysis. This new nanocatalyst displays a good activity toward the aerobic oxidation of a wide range of alcohols in water. Moreover, it is recyclable up to five following runs by simple filtration without any significant loss of its catalytic activity.
- Dehkordi, S. Saeid Saei,Albadi, Jalal,Jafari, Abbas Ali,Samimi, Heshmat Allah
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p. 2527 - 2538
(2021/03/24)
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- Dioxido-vanadium(V) complex catalyzed oxidation of alcohols and tandem synthesis of oximes: a simple catalytic protocol for C–N bond formation
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We report the synthesis of a vanadium(V) complex characterized by FT-IR and 1H NMR spectroscopy. The structure of the complex was established by single crystal X-ray crystallography. We also carried out the catalytic oxidation of benzyl alcohol, hetero-aryl alcohols and propargylic alcohols. Tandem synthesis of oximes from alcohols were also carried out using our vanadium(V) complex. The newly synthesized complex acts as a catalyst for oxidation reactions and tandem synthesis of oxime from alcohols.
- Kurbah, Sunshine Dominic
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p. 905 - 918
(2021/02/03)
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- Synthesis, characterization, reactivity, and catalytic studies of heterobimetallic vanadium(V) complexes containing hydrazone ligands
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Six heterobimetallic alkali metal dioxidovanadium(V) coordination polymer complexes {[M6{VO(μ-O)}2(μ-OH)4(μ4-slox/nph)].n DMF}∞ where M = Na, K, and Cs; n = 1 for (1), 0 for (2)-(6) of two dihydrazone ligands, disalicylaldehydeoxaloyldihydrazone (H4slox) and bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (H4nph) are reported. All the complexes have been characterized by various physicochemical techniques such as elemental analyses, molar conductance, IR, NMR, UV–vis, and cyclic voltammetry. The IR, 1HNMR, and 13CNMR spectral data suggest that the dihydrazones are coordinated through phenolate/naphtholate oxygen, enolate oxygen, and azine nitrogen atoms to the metal centres. The structure of complex {[Na6{VO(μ-O)}2(μ-OH)4(μ4-slox)].DMF}∞ (1) is also determined by single-crystal X-ray data, which revealed that the H4slox coordinated via all possible dative sites to metal centres as tetrabasic octadentate ligand. The vanadium metal centres adopted distorted square-pyramidal coordination geometries, and the sodium atoms are also in five coordination atmospheres. The electronic spectra of the complexes showed LMCT bands in addition to intra-ligand π → π* and n → π* transitions. As evident from the cyclic voltammetry, the complexes showed two metal-centred electron transfer reactions {[(VVVV(slox)2?/VVVIV(slox)3?] and [(VVVIV(slox)3?/VVVIV(slox)4?]}, in addition to the ligand centred electron transfer reactions. Further, bovine serum albumin (BSA interaction studies of the complexes {[Na6{VO(μ-O)}2(μ-OH)4(μ4-slox)].DMF}∞ (1) and [Na6{VO(μ-O)}2(μ-OH)4(μ4-nph)]∞ (4) revealed strong binding affinity. Moreover, the catalytic studies of the complexes (1) and (4) were found to be effective for the oxidation of alcohols into their corresponding aldehydes and ketones and bromination of some organic substrates in the presence of H2O2 as an oxidizing agent.
- Borthakur, Rosmita,Dhanpat, Shobha A.,Kumar, Arvind,Kurbah, Sunshine D.,Lal, Ram A.,Syiemlieh, Ibanphylla
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- Designing of Highly Active and Sustainable Encapsulated Stabilized Palladium Nanoclusters as well as Real Exploitation for Catalytic Hydrogenation in Water
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Abstract: Encapsulated nanoclusters based on palladium, 12-tunstophosphoric acid and silica was designed by simple wet impregnation methodology. The catalyst was found to be very efficient towards cyclohexene hydrogenation up to five catalytic runs with substrate/catalyst ratio of 4377/1 at 50?°C as well as for alkene, aldehyde, nitro and halogen compounds. Graphic Abstract: Silica encapsulated Pd nanoclusters stabilized by 12-tungstophosphoric acid is proved to be sustainable and excellent for water mediated hydrogenation reaction with very high catalyst to substrate ratio as well as TON.[Figure not available: see fulltext.]
- Patel, Anish,Patel, Anjali
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p. 803 - 820
(2020/08/12)
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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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- Probing the Interface between Encapsulated Nanoparticles and Metal-Organic Frameworks for Catalytic Selectivity Control
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Encapsulating metal nanoparticles (NPs) in metal-organic frameworks (MOFs) to control catalytic selectivity has recently attracted great attention; however, an understanding of the NP-MOF interface is lacking. In this work, we used spectroscopy to investi
- Lo, Wei-Shang,Chou, Lien-Yang,Young, Allison P.,Ren, Chenhao,Goh, Tian Wei,Williams, Benjamin P.,Li, Yang,Chen, Sheng-Yu,Ismail, Mariam N.,Huang, Wenyu,Tsung, Chia-Kuang
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- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
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As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
- Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
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supporting information
p. 8040 - 8046
(2021/11/01)
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- Solvent-free oxidation of straight-chain aliphatic primary alcohols by polymer-grafted vanadium complexes
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Oxidovanadium(IV) complexes [VO(tertacac)2] (1), [VO(dipd)2] (2), and [VO(phbd)2] (3) were synthesized by reacting [VO(acac)2] with 2,2,6,6-tetramethyl-3,5-hepatanedione, 1,3-diphenyl-1,3-propanedione, and 1-phenyl-1,3-butanedione, respectively. Imidazole-modified Merrifield resin was used for the heterogenization of complexes 1–3. During the process of heterogenization, the V4+ center in complex 2 converts into V5+, whereas the other two complexes 1 and 3 remain in the oxidovanadium(IV) state in the polymer matrix. Theoretically, calculated IPA values of 1–3 suggest that 2 is prone to oxidation compared with 1 and 3, which was also supported by the absence of EPR lines in 5. Polymer-supported complexes Ps-Im-[VIVO(tertacac)2] (4), Ps-Im-[VVO2(dipd)2] (5), and Ps-Im-[VIVO(phbd)2] (6) were applied for the solvent-free heterogenous oxidation of a series of straight-chain aliphatic alcohols in the presence of H2O2 at 60°C and showed excellent substrate conversion specially for the alcohols with fewer carbon atoms. Higher reaction temperature improves the substrate conversion significantly for the alcohols containing more carbon atoms such as 1-pentanol, 1-hexanol, and 1-heptanol while using optimized reaction conditions. However, alcohols with fewer carbon atoms seem less affected by reaction temperatures higher than the optimized temperature. A decreasing trend in the selectivity(%) of carboxylic acid was observed with increasing carbon atoms among the examined alcohols, whereas the selectivity towards aldehydes increased. The order of efficiency of the supported catalysts is 4 > 6 > 5 in terms of turnover frequency (TOF) values and substrate conversion, further supported by theoretical calculations.
- Chaudhary, Nikita,Haldar, Chanchal,Kachhap, Payal
-
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- Investigating hydrogenation and decarbonylation in vapor-phase furfural hydrotreating over Ni/SiO2 catalysts: Propylene production
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Furfural can be mass-produced from lignocellulose biomass and can be a platform chemical for producing valuable chemicals. In this study, we examine Ni/SiO2 catalysts for the conversion of furfural under a hydrogen atmosphere. The reactivity an
- Chen, Szu-Hua,Tseng, Ya-Chun,Yang, Sheng-Chiang,Lin, Shawn D.
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- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
-
Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
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-
- Synthesis of Butadiene from Formaldehyde and Propylene on Cesium Salts of Silicotungstic Heteropoly Acid
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Abstract: A one-stage gas-phase synthesis of butadiene from formaldehyde and propylene on silica-supported cesium salts of silicotungstic heteropoly acid was realized for the first time. The physicochemical properties of the catalysts were studied by X-ray fluorescence analysis, low-temperature nitrogen adsorption, XRD, SEM, Raman spectroscopy, and NH3–TPD. The coke deposits were studied by the TGA–DTA method. Analysis of the catalytic properties showed that an increase in the concentration of cesium atoms in CsxH4–xSiW12O40/SiO2 (x = 0–3) has a beneficial effect on the endurance of the catalyst but is accompanied by a decrease in activity and butadiene selectivity. In the case of CsH3SiW12O40/SiO2, the butadiene selectivity was 51 mol %. [Figure not available: see fulltext.]
- Dobryakova, I. V.,Ivanova, I. I.,Kasyanov, I. A.,Matveeva, О. D.,Nikiforov, A. I.,Ponomareva, О.А.,Shkuropatov, A. V.
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p. 916 - 924
(2021/08/16)
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- Selective dehydration of 1-butanol to butenes over silica supported heteropolyacid catalysts: Mechanistic aspect
-
Butenes are considered as important olefinic building block to produce fuels/fuel additives and commodity chemicals. In the present investigation, selective dehydration of 1-butanol to butenes was studied in a continuous-flow fixed-bed reactor using various silica-supported heteropolyacid (HPA) catalysts such as phosphotungstic acid (PTA), silicotungstic acid (STA), phosphomolybdic acid (PMA), and silicomolybdic acid (SMA) as the solid acid catalysts. The physicochemical properties of these HPA were determined by BET, powder XRD, FTIR, NH3-TPD, and Py-FTIR. The acid strength and Br?nsted/Lewis (B/L) acid ratio were increased with higher loading of HPA on silica. The nature of HPA (addenda and hetero atom) and loading of HPA are important factors for the dehydration of 1-butanol and selectivity towards butenes. PTA and STA showed superior catalytic activity than PMA and SMA. The reaction temperature and WHSV also strongly affected the butanol conversion and selectivity of butenes. The selectivity of di-n?butyl ether decreases with the rising temperature from 523 K to 623 K. The isomerization of 1-butene leading to the formation of other butene isomers depends on the HPA loading, temperature, and WHSV. The presence of molybdenum addendum atom in PMA and SMA promotes dehydrogenation and hydrogenation, leading to the formation of various light hydrocarbons. The 20PTA/SiO2 catalyst afforded 99.8% selectivity towards butenes at quantitative conversion of 1-butanol, whereas the 20STA/SiO2 catalyst gave nearly 97.0% conversion of 1-butanol and 99.9% butenes selectivity at 673 K, 37.4 h?1 of WHSV.
- Dutta, Saikat,Kella, Tatinaidu,Mal, Sib Sankar,Shee, Debaprasad,Vennathan, Anjana Anandan
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- METHOD FOR PRODUCING CARBONATE DERIVATIVE
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The objective of the present invention is to provide a method for producing a polycarbonate safely and efficiently even without using a base. The method for producing a carbonate derivative according to the present invention is characterized in comprising the step of irradiating a high energy light to a composition comprising the halogenated methane and the hydroxy group-containing compound in the presence of oxygen, wherein a molar ratio of a total usage amount of the hydroxy group-containing compound to 1 mole of the halogenated methane is 0.05 or more.
- -
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Paragraph 0122-0123
(2022/01/04)
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- Organic Ligand-Free Hydroformylation with Rh Particles as Catalyst?
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An efficient and organic ligand-free heterogeneous catalytic system for hydroformylation of olefins is highly desirable for both academy and industry. In this study, simple Rh black was employed as a heterogeneous catalyst for hydroformylation of olefins in the absence of organic ligand. The Rh black catalyst showed good catalytic activity for a broad substrate scope including the aliphatic and aromatic olefins, affording the desired aldehydes in good yields. Taking the hydroformylation of ethylene as an example, 86% yield of propanal and TOF of 200 h–1 were obtained, which was superior to the reported homogeneous catalytic systems. In addition, the catalyst could be reused five times without loss of activity under identical reaction conditions, and the Rh leaching was negligible after each cycle.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Wang, Xinzhi,Shi, Feng
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p. 139 - 143
(2020/01/03)
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- DIHYDROXYBIPHENYL COMPOUND, BISPHOSPHITE COMPOUND, CATALYST, PRODUCTION METHOD OF ALDEHYDES, AND PRODUCTION METHOD OF ALCOHOL
-
An object of the present invention is to provide a bisphosphite compound giving higher selectivity for the target product with maintaining a high reaction rate. The present invention relates to a dihydroxybiphenyl compound represented by the following formula (1) and a bisphosphite compound represented by the following formula (2): wherein in formulae (1) and (2), each of R1 to R4, R11 to R14, and Z1 to Z4 is the same as defined in the description.
- -
-
Paragraph 0170-0172
(2020/07/05)
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- Solvent-free, microwave assisted oxidation of alcohols with 4-hydroxypyridinium chlorochromate functionalized silica gel
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4-Hydroxypyridinium chlorochromate functionalized silica gel was found to be an efficient and reusable oxidant for the very fast oxidation of primary and secondary alcohols to the corresponding carbonyl compounds under solventfree conditions and microwave irradiation in excellent yields.
- AHMADI, Sayed Ali,GHALEHBANDI, Shermineh Sadat,GHAZANFARI, Dadkhoda,SHEIKHHOSSEINI, Enayatollah
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p. 283 - 289
(2020/10/06)
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- Triruthenium carbonyl complexes containing bidentate pyridine–alkoxide ligands for highly efficient oxidation of primary and secondary alcohols
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Reactions of substituted pyridylalkanol 6-CH3PyCH2CH(OH)R (R?=?Ph (L1H), R?=?4-CH3C6H4 (L2H), R?=?4-OCH3C6H4 (L3H), R?=?4-ClC6H4 (L4H), R?=?4-BrC6H4 (L5H), R?=?4-CF3C6H4 (L6H)) with Ru3(CO)12 in refluxing tetrahydrofuran afforded the corresponding ruthenium carbonyl complexes [6-CH3PyCH2CHRO]2Ru3(CO)8 (R?=?Ph (1a), R?=?4-CH3C6H4 (1b), R?=?4-OCH3C6H4 (1c), R?=?4-ClC6H4 (1d), R?=?4-BrC6H4 (1e), R?=?4-CF3C6H4 (1f)) in good yields. These ruthenium complexes were well characterized using elemental analysis and Fourier transform infrared and NMR spectroscopies. Furthermore, their crystal structures were determined using single-crystal X-ray diffraction analysis. Complexes 1a–1f were found to be highly active toward oxidation of a wide range of primary and secondary alcohols to corresponding aldehydes and ketones within 5?minutes in the presence of N-methylmorpholine-N-oxide as oxidant.
- Yue, Xiaohui,Yan, Xinlong,Huo, Shuaicong,Dong, Qing,Zhang, Junhua,Hao, Zhiqiang,Han, Zhangang,Lin, Jin
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- Design and synthesis of a versatile cooperative catalytic aerobic oxidation system with co-immobilization of palladium nanoparticles and laccase into the cavities of MCF
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We have designed a versatile reusable cooperative catalyst oxidation system, consisting of palladium nanoparticles and laccase with unprecedented reactivity. This biohybrid catalyst was synthesized by the stepwise immobilization of laccase as an enzyme and Pd as a nanometallic component into the same cavity of siliceous mesocellular foams (MCF). MCF and nanobiohybrid catalyst were characterized by BET, SAXS, SEM, EDX elemental mapping, ICP-OES, TEM, TGA, FT-IR, and XPS techniques and the stepwise immobilization of laccase enzyme and Pd onto MCF was evaluated through several compelling electrochemical studies. The present catalytic system exhibits high activity toward (i) aerobic oxidation of alcohols to the corresponding carbonyl compounds, (ii) aerobic oxidation of cyclohexanol and cyclohexanone to phenol and (iii) aerobic dehydrogenation of important N-heteocyclic compounds (tetrahydro quinazolines, quinazolonones, pyrazolines and 1,4-diydropyridines) in the presence of catalytic amount of hydroquinone (HQ) as mediator in phosphate buffer (0.1 M, pH 4.5, 4 mL)/THF (4%, 1 mL) as solvent under mild conditions. The immobilization of both oxygen-activating catalyst (laccase) and oxidizing catalyst (Pd) onto the same support makes the present catalyst system superior to other currently available heterogeneous palladium based catalytic aerobic oxidation systems.
- Moradi, Sirvan,Shokri, Zahra,Ghorashi, Nadya,Navaee, Aso,Rostami, Amin
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p. 305 - 319
(2020/01/21)
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- Gas phase transfer hydrogenation of α, β- unsaturated carbonyl compounds into saturated carbonyl compounds over supported Cu catalysts
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This work aims to produce hydrocinnamaldehyde via selective C[dbnd]C bond hydrogenation of cinnamaldehyde via transfer hydrogenation catalyzed by supported Cu catalysts. The catalytic activity and characterization results demonstrated that conversion of cinnamaldehyde and selectivity to hydrocinnamaldehyde is an integrated result of active Cu metal surface area and nature of support material. In the case of Cu/SiO2 catalysts, the rate of formation of hydrocinnamaldehyde was linearly dependent on the active Cu metal surface area. A maximum rate of formation of hydrocinnamaldehyde 167.82 μmol.g?1.s-1 was obtained at an active Cu metal surface area of 6.1 m2.gcat-1 over 20 wt. % Cu/SiO2 catalyst. While in the case of other supported Cu catalysts (Cu/MgO, Cu/ZrO2 and Cu/γ-Al2O3) along with the active Cu metal surface area, the surface acidity and basicity governed the selectivity of hydrocinnamaldehyde. The rate of formation of hydrocinnamaldehyde followed the trend Cu/SiO2 >Cu/Al2O3 >Cu/MgO > Cu/ZrO2. Unlike Cu/SiO2 catalyst, the competitive adsorption of C[dbnd]C and CO[dbnd] bonds over these (Al2O3, MgO and ZrO2) supported Cu catalysts altered the selectivity of hydrocinnamaldehyde. Cu/SiO2 catalyst was superior in selective C[dbnd]C hydrogenation of α, β-unsaturated carbonyl compounds via transfer hydrogenation. Cyclohexenone, isophorone and crotonaldehyde were selectively converted into their saturated carbonyl compounds.
- K, Saidulu Reddy,Enumula, Siva Sankar,Koppadi, Kumara Swamy,Rao Kamaraju, Seetha Rama,Burri, David Raju
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- Biosynthesis of Mycotoxin Fusaric Acid and Application of a PLP-Dependent Enzyme for Chemoenzymatic Synthesis of Substituted l -Pipecolic Acids
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Fusaric acid (FA) is a well-known mycotoxin that plays an important role in plant pathology. The biosynthetic gene cluster for FA has been identified, but the biosynthetic pathway remains unclarified. Here, we elucidated the biosynthesis of FA, which features a two-enzyme catalytic cascade, a pyridoxal 5′-phosphate (PLP)-dependent enzyme (Fub7), and a flavin mononucleotide (FMN)-dependent oxidase (Fub9) in synthesizing the picolinic acid scaffold. FA biosynthesis also involves an off-line collaboration between a highly reducing polyketide synthase (HRPKS, Fub1) and a nonribosomal peptide synthetase (NRPS)-like carboxylic acid reductase (Fub8) in making an aliphatic α,β-unsaturated aldehyde. By harnessing the stereoselective C-C bond-forming activity of Fub7, we established a chemoenzymatic route for stereoconvergent synthesis of a series of 5-alkyl-, 5,5-dialkyl-, and 5,5,6-trialkyl-l-pipecolic acids of high diastereomeric ratio.
- Hai, Yang,Chen, Mengbin,Huang, Arthur,Tang, Yi
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supporting information
p. 19668 - 19677
(2020/12/01)
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- Method for preparing aldehyde by olefin hydroformylation
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The invention relates to a method for preparing aldehyde through olefin hydroformylation. The method comprises the steps: enabling alpha-olefin and synthesis gas to enter a hydroformylation reactor; carrying out a contact reaction on alpha-olefin and synthesis gas with a catalyst to generate an aldehyde-containing product, wherein the catalyst comprises a main catalyst and a co-catalyst, the maincatalyst is a complex catalyst and comprises a rhodium complex and a phosphine ligand, the phosphine ligand is tris[2,4-di-tert-butylphenyl]phosphite, and the co-catalyst is a nickel-palladium bimetallic phosphinate. The method has the advantages of high normal-to-abnormal ratio in the product, good selectivity and yield, mild reaction conditions and the like.
- -
-
Paragraph 0032-0034; 0035-0039
(2020/07/15)
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- Unsaturated Alcohols as Chain-Transfer Agents in Olefin Polymerization: Synthesis of Aldehyde End-Capped Oligomers and Polymers
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Palladium diimine-catalyzed polymerization of olefins using unsaturated alcohols as chain-transfer agents has been demonstrated. The reaction affords aldehyde end-capped polymers whose molecular weight can be tuned by varying the ratio of olefin/chain-transfer agent. Notably, >95% efficient end capping with aldehyde can be achieved under optimized conditions. This end-capping procedure is a rare example of introducing a highly reactive and versatile terminal functionality in polyolefin chains using a functional group-tolerant late metal catalyst. The reactivity of these end-capped polymers is illustrated here via functionalization with dyes to yield colored, hydrocarbon-soluble polyolefin derivatives.
- Han, Xing-Wang,Daugulis, Olafs,Brookhart, Maurice
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p. 15431 - 15437
(2020/10/02)
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- SATURATED HOMOETHER MANUFACTURING METHOD FROM UNSATURATED CARBONYL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for manufacturing saturated homoether from an unsaturated carboxyl compound at good efficiency. SOLUTION: There is provided a manufacturing method of saturated homoether using an unsaturated carboxyl compound and hydrogen as raw materials, and a catalyst in which a metal is carried on an acidic catalyst carrier. The metal of the catalyst is for example palladium, and the carrier of the catalyst is alumina, silica, silica-alumina, or the like. The unsaturated carbonyl compound as the raw material is 2-butenal, 2-ethyl-2-hexenal, 2-ethyl-2-butenal, 2-hexenal, and manufactured saturated homoether is dibuthylether, bis(2-ethylhexyl)ether, bis(2-ethylbuty)ether, dihexylether, or the like. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPO&INPIT
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Paragraph 0045-0046
(2020/05/14)
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- Single-reactor conversion of ethanol to 1-/2-butenes
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A simplified processes for producing desired chemicals such as butenes from feedstock mixtures containing ethanol. In one set of embodiments this is performed in a single step, wherein a feed containing ethanol in a gas phase is passed over an acidic metal oxide catalyst having a transition metal dispersion of at least 5% on a metal oxide support. The ethanol content of the feedstock mixture may vary from 10 to 100 percent of the feed and in those non-eat applications the ethanol feed may contain water.
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Page/Page column 5
(2020/06/03)
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- Upgrading 1-butanol to unsaturated, carbonyl and aromatic compounds: A new synthesis approach to produce important organic building blocks
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Unsaturated, carbonyl and aromatic products were obtained by reacting 1-butanol or a 1-butanol:methanol mixture with a copper mixed metal oxide catalyst in a fixed bed reactor. The selectivities observed, mostly for the unsaturated and carbonyl products, can represent a new alternative and greener pathway for the production of fine-chemicals and organic building blocks.
- Boscolo, Mauricio,Metzker, Gustavo,Mora Vargas, Jorge,Orduna Ortega, Julieth,Tofaneli Morelato, Luiz Henrique
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supporting information
p. 2365 - 2369
(2020/05/13)
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- Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound i Type Oxidants
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The reductive activation of molecular oxygen catalyzed by iron-based enzymes toward its use as an oxygen donor is paradigmatic for oxygen transfer reactions in nature. Mechanistic studies on these enzymes and related biomimetic coordination compounds designed to form reactive intermediates, almost invariably using various "shunt" pathways, have shown that high-valent Fe(V)=O and the formally isoelectronic Fe(IV) =O porphyrin cation radical intermediates are often thought to be the active species in alkane and arene hydroxylation and alkene epoxidation reactions. Although this four decade long research effort has yielded a massive amount of spectroscopic data, reactivity studies, and a detailed, but still incomplete, mechanistic understanding, the actual reductive activation of molecular oxygen coupled with efficient catalytic transformations has rarely been experimentally studied. Recently, we found that a completely inorganic iron-tungsten oxide capsule with a keplerate structure, noted as {Fe30W72}, is an effective electrocatalyst for the cathodic activation of molecular oxygen in water leading to the oxidation of light alkanes and alkenes. The present report deals with extensive reactivity studies of these {Fe30W72} electrocatalytic reactions showing (1) arene hydroxylation including kinetic isotope effects and migration of the ipso substituent to the adjacent carbon atom ("NIH shift"); (2) a high kinetic isotope effect for alkyl C - H bond activation; (3) dealkylation of alkylamines and alkylsulfides; (4) desaturation reactions; (5) retention of stereochemistry in cis-alkene epoxidation; and (6) unusual regioselectivity in the oxidation of cyclic and acyclic ketones, alcohols, and carboxylic acids where reactivity is not correlated to the bond disassociation energy; the regioselectivity obtained is attributable to polar effects and/or entropic contributions. Collectively these results also support the conclusion that the active intermediate species formed in the catalytic cycle is consistent with a compound I type oxidant. The activity of {Fe30W72} in cathodic aerobic oxidation reactions shows it to be an inorganic functional analogue of iron-based monooxygenases.
- Bugnola, Marco,Shen, Kaiji,Haviv, Eynat,Neumann, Ronny
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p. 4227 - 4237
(2020/05/05)
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- Synthesis of α,β- and β-Unsaturated Acids and Hydroxy Acids by Tandem Oxidation, Epoxidation, and Hydrolysis/Hydrogenation of Bioethanol Derivatives
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We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C4 aldehydes via base-catalyzed aldol-condensation. Then, the resulting C4 adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield). Using a sequential epoxidation and hydrogenation of crotonic acid leads to 29 % yield of β-hydroxy acid (3-hydroxybutanoic acid). By controlling the pH of the reaction media, it is possible to hydrolyze the oxirane moiety leading to 21 % yield of α,β-dihydroxy acid (2,3-dihydroxybutanoic acid). Crotonic acid, 3-hydroxybutanoic acid, and 2,3-dihydroxybutanoic acid are archetypal specialty chemicals used in the synthesis of polyvinyl-co-unsaturated acids resins, pharmaceutics, and bio-degradable/ -compatible polymers, respectively.
- Faria, Jimmy,Komarneni, Mallik R.,Li, Gengnan,Pham, Tu,Resasco, Daniel E.,Ruiz, Maria P.,Santhanaraj, Daniel
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supporting information
p. 7456 - 7460
(2020/03/23)
-
- Selective oxidation of: N -buthanol to butyraldehyde over MnCo2O4spinel oxides
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Partial oxidation of n-butanol to butyraldehyde, propionaldehyde and acetaldehyde over MnCo2O4 spinel oxides has been investigated. Physicochemical characteristics of samples, prepared by co-precipitation with different amounts of precipitating agent, were studied by XRD, N2 adsorption-desorption isotherms, FT-IR, SEM and XPS. The ratio between the precipitating agent and the precursors has a considerable influence both on the structure, which is evidenced by XRD, due to switching from a crystalline structure to an amorphous one and on the surface (XPS) by an obvious change in the ratio Co3+/Co2+ and Mn4+/Mn3+ and in the content of oxygen vacancies. The reaction rate is not influenced by the oxygen pressure, emphasizing that n-butanol oxidation occurs through the Mars van Krevelen mechanism. The conversion of n-butanol and yield of butyraldehyde are directly proportional to the cobalt content on the surface, while the propionaldehyde yield is proportional to the Mn4+/Mn3+ ratio.
- Chen, Shaojiang,Mitran, Gheorghita,Seo, Dong-Kyun
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p. 25125 - 25135
(2020/07/14)
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- Highly active and durable WO3/Al2O3catalysts for gas-phase dehydration of polyols
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Gas-phase glycerol dehydration over WO3/Al2O3catalysts was investigated. WO3loading on γ-Al2O3significantly affected the yield of acrolein and the catalyst with 20 wt% WO3loading showed the highest activity. The WO3/Al2O3catalyst with 20 wt% WO3loading showed higher activity and durability than the other supported WO3catalysts and zeolites. The number of Br?nsted acid sites and mesopores of the WO3/Al2O3catalyst did not decrease after the reaction, suggesting that glycerol has continuous access to Br?nsted acid sites inside the mesopores of WO3/Al2O3, thereby sustaining a high rate of formation of acrolein. Dehydration under O2flow further increased the durability of the WO3/Al2O3catalyst, enabling the sustainable formation of acrolein. In addition, the WO3/Al2O3catalyst with 20 wt% WO3loading showed high activity for the dehydration of various polyols to afford the corresponding products in high yield.
- Aihara, Takeshi,Asazuma, Katsuya,Miura, Hiroki,Shishido, Tetsuya
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p. 37538 - 37544
(2020/10/19)
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- High iso Aldehyde Selectivity in the Hydroformylation of Short-Chain Alkenes
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The hydroformylation of propene to give predominantly iso-butanal has been achieved; class-leading selectivity is possible even at higher temperatures that deliver fast conversion. Racemic rhodium complexes of bidentate phospholane phosphites derived from tropos-biphenols and unusual solvent systems are the key to the selectivity observed.
- Iu, Leo,Fuentes, José A.,Janka, Mesfin E.,Fontenot, Kevin J.,Clarke, Matthew L.
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supporting information
p. 2120 - 2124
(2019/01/25)
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- A METHOD FOR THE ALDEHYDE BY HYDROFORMYLATION REACTION
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The present invention relates to a method for producing aldehydes by hydroformylation. More specifically, the present invention relates to a method for producing aldehydes which can secure economic efficiency of the process such as reduction of raw material cost and enhancement of productivity by reducing heavy by-products by suppressing aldol reaction of the hydroformylation products when post-treating using a simple, quick, and cheap method and increasing the production amount of aldehydes.(AA) Synthetic gas + olefin(BB) Water(i) Reactor(ii) Distillation apparatus(iii) Fractionation tankCOPYRIGHT KIPO 2019
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Paragraph 0073; 0076-0085; 0090-0103
(2019/04/09)
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- Highly isoselective catalyst for alkene hydroformylation
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Ligands for use with catalyst compositions used in hydroformylation reactions are described herein. The ligands are used with various ester solvents and achieve an increase in isoselectivity with an increase in temperature, an increase in TON with an increase in temperature, and/or will show isoselectivity that is surprisingly high in comparison to the hydroformylation reactions using common solvents.
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Page/Page column 10; 11; 12; 13
(2019/02/07)
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- Method for preparing ketone or carboxylic acid through catalytic oxidation of secondary alcohol or primary alcohol
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The invention relates to a method for preparing ketone or carboxylic acid through catalytic oxidation of alcohol. The method specifically comprises the following steps: adding secondary alcohol or primary alcohol into a certain amount of organic solvent to serve as a raw material, forming an N-hydroxyphthalimide (NHPI)-phthalocyanine catalytic system and taking oxygen as an oxidant, and reacting for 9-36 hours at the reaction temperature of 60-120 DEG C under the condition of normal pressure to obtain the ketone or carboxylic acid with higher yield. Compared with the prior art, the method hasthe advantages of green and environment-friendly oxidant, cheap and easily-prepared catalyst, easiness in separation from the product, mild reaction conditions and the like, and is a green alcohol oxidation method.
- -
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Paragraph 0054-0057
(2019/12/02)
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- Catalytic synthesis of distillate-range ethers and olefins from ethanol through Guerbet coupling and etherification
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Synthesis of distillate-range fuels from biomass-derived alcohols has recently received considerable attention due to projected increases in the demands of these fuels and the extensive commercialization of alcohol production. Here we present a two-stage process by which an alcohol such as ethanol or 1-butanol can be converted with high yields into distillate-range ethers and olefins by combining Guerbet coupling and intermolecular dehydration. The ethers can be used as cetane-improvers in diesel fuel, while the olefins can be hydrogenated and blended with gasoline or oligomerized and hydrogenated to jet-range paraffins. The first stage was executed using calcium hydroxyapatite to produce higher linear and branched alcohols at above 80% selectivity at up to 40% conversion with high stability for over 400 h time-on-stream operation. Increasing conversion decreases selectivity, producing predominantly mono-ene and diene byproducts. Etherification was performed using the acidic resin Amberlyst 70 at around 65% conversion. Linear alcohols were converted at above 90% selectivity while branched alcohols were far more selective to olefins (65-75%). Etherification occurs via two mechanisms: a direct mechanism involving the reaction of two alcohols and an indirect mechanism between an alcohol and equilibrated pool of olefins. Cross-etherification was observed between linear and branched alcohols, improving the selectivity to ethers in conversion of the latter. A mixture of C4+ alcohols produced from ethanol condensation at 40% conversion was effectively utilized in etherification at selectivities comparable to the model mixtures. An overall process is presented for the conversion of ethanol to diesel-range ethers and olefins with yields of approximately 80%.
- Eagan, Nathaniel M.,Moore, Benjamin M.,McCelland, Daniel J.,Wittrig, Ashley M.,Canales, Emmanuel,Lanci, Michael P.,Huber, George W.
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p. 3300 - 3318
(2019/06/24)
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- Highly efficient and practical aerobic oxidation of alcohols by inorganic-ligand supported copper catalysis
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The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations.
- Wei, Zheyu,Ru, Shi,Zhao, Qixin,Yu, Han,Zhang, Gang,Wei, Yongge
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supporting information
p. 4069 - 4075
(2019/08/07)
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- An Efficient Eco-friendly Modified Palladium, Immobilized on Imidazolium Supported Bi-functionalized Ionic Liquid for Selective Oxidation of Alcohols
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An efficient method for the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, with hydrogen peroxide under ambient temperature has been achieved. By applying catalytic amount of palladium-bifunctional ionic liquid in the presence of solvent-free condition, a variety of substrates were selectively oxidized without the formation of ester by-products. The material also exhibited reusability as well as reaction time stability properties desired for industrial applications.
- Ashok, R. Francis Nicholas,Balan, A. Maria Kulandai Raja,Vasanthi, M.
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- Half-sandwich ruthenium-based versatile catalyst for both alcohol oxidation and catalytic hydrogenation of carbonyl compounds in aqueous media
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A series of half-sandwich ruthenium-based catalysts for both alcohol oxidation and carbonyl compounds hydrogenation have been synthesized through metal-induced C–H bond activation based on benzothiazole ligands. The neutral ruthenium complexes 1–4 were fully characterized by UV–vis, NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 3 were further confirmed by X-ray diffraction analysis. All complexes exhibited high activity for the catalytic oxidation of a variety of alcohols with tBuOOH as oxidants to give carbonyl compounds with high yields in water. Moreover, these half-sandwich complexes also showed high efficiency for the catalytic hydrogenation of carbonyl compounds in a methanol–water mixture. The catalyst could be reused for at least five cycles without any loss of activity. The catalytic system also worked well for various kinds of substrates with either electron-donating or electron-withdrawing groups.
- Qiao, Xin-Chao,Qiu, Dan-Chen,Lin, Nan,Zhu, Jing-Wei,Deng, Wei,Yao, Zi-Jian
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