- HOMOGENEOUS HYDROGENATION OF KETONES TO ALCOHOLS WITH RUTHENIUM COMPLEX CATALYSTS
-
A number of ruthenium triphenylphosphine complexes catalyse the reduction of ketones to their corresponding alcohols in the presence of water.The most convenient catalyst precursors are carbonyl containing complexes which do not promote decarbonylation of the substrate.The hydrogenation of acetone with hydridochlorocarbonyltris(triphenylphosphine)ruthenium is first order with respect to the substrate concentration, the catalyst concentration, the hydrogen pressure and the water concentration.Turnover numbers up to 15,000 have been achieved with this catalyst.Other ketones are also reduced by RuHCl(CO)(PPh3)3 and the rate of the reaction is dependent on the nature of the substrate.
- Sanchez-Delgado, R.A.,Ochoa, O.L. De
-
-
Read Online
- Improved (photo)catalytic propene hydration in a gas/solid system by using heteropolyacid/oxide composites: Electron paramagnetic resonance, acidity, and role of water
-
Binary materials composed of the oxides SiO2, TiO2 and N-doped TiO2 and the Keggin heteropolyacid (PW12) were prepared and physicochemically characterized. They were used as catalysts and photocatalysts for the hydration of propene to 2-propanol. The characterization of the samples, particularly the electron paramagnetic resonance (EPR) spectroscopy results and the acidity properties, were useful to explain the key role played by the PW12 in the composite materials in the thermal and photoassisted catalytic processes. The simultaneous pres-ence of heat and UV light improved the activity of PW12 in the thermal process, and the binary materials showed better (photo)catalytic activities than that of the bare PW12 in almost all cases. For the first time, this work evidenced through EPR spectroscopy that the increase of reactivity under irradiation could be attributed to the ability of photoexcited PW12 to trap electrons, particularly if the PW12 is supported. Moreover, the effect of water on the reactivity was also studied.
- García-López, Elisa I.,Marcì, Giuseppe,Pomilla, Francesca R.,Liotta, Leonarda F.,Megna, Bartolomeo,Paganini, Maria C.,Gionco, Chiara,Giamello, Elio,Palmisano, Leonardo
-
-
Read Online
- Rh-CeO2 Interaction induced by High-temperature Reduction. Characterization and Catalytic Behaviour in Transient and Continuous Conditions
-
The effects of the high-temperature reduction of Rh/CeO2 catalyst on the hydrogenation of CO, CO2, acetone and ethene, and on the hydrogenolysis of ethane, in transient and continuous conditions, have been investigated.The high-temperature reduction (HTR) at 773 K induced a transient Rh-CeO2 interaction in the catalyst which enhances the rate of CO, CO2 and acetone hydrogenation.Temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) show the reduction of Ce4+ to Ce3+ after HTR in the near surface layers.We suggest that the oxygen vacancies on the support (i.e. presence of Ce3+) can interact with the CO moiety promoting its activation.
- Trovarelli, Alessandro,Dolcetti, Giuliano,Leitenburg, Carla de,Kaspar, Jan,Finetti, Paola,Santoni, Antonino
-
-
Read Online
- Kinetics of an Associative Ligand-Exchange Process: Alcohol Exchange with Arsenate(V) Triesters
-
The rate of alcohol exchange with trialkyl arsenates has been studied by three techniques.Exchange of the straight-chain alcohols (ethyl, n-propyl, n-butyl, and n-pentyl) was studied in acetonitrile solution by using proton NMR line broadening.Activation enthalpies and entropies were found in the ranges 1 to 6kJ mol-1 and -204 and -226 J mol-1 K-1, respectively.The reactions are subject to acid catalysis for which slightly higher ΔH and less negative ΔS values were found.Methyl exchange, studied by the same technique, is about one powere of ten faster.Isopropyl exchange, about three powers of ten slower, was studied in acetonitrile and dichloromethane solutions by deuterium labeling, using proton NMR.The interchange reaction of benzyl alcohol with triisopropyl arsenate in acetonitrile or dichloromethane was followed by spectrophotometry.Hydrogen bonding between alcohol and ester (which complicates order determination) was observed when reactants were at concentrations greater than about 10-2 M.The strongly associative mechanism is discussed.
- Baer, Carl D.,Edwards, John O.,Kaus, Malcolm J.,Richmond, Thomas G.,Rieger, Philip H.
-
-
Read Online
- The heme monooxygenase cytochrome P450cam can be engineered to oxidize ethane to ethanol
-
(Graph Presented) A NADH turnover rate of 741 min-1 in the oxidition of ethane to ethanol is observed with an engineered form of the heme monooxygenase cytochrome P450cam - the first example of such activity for a P450 enzyme (CC analysis shown). Ethanol is formed at 78 min-1 (10.5 % coupling). The mutant is ≈45 % high-spin in the absence of substrate, making it a useful platform for P450 structure-function studies.
- Xu, Feng,Bell, Stephen G.,Lednik, Jaka,Insley, Andrew,Rao, Zihe,Wong, Luet-Lok
-
-
Read Online
- Hydrodeoxygenation of glycerol into propanols over a Ni/WO3–TiO2 catalyst
-
Hydrodeoxygenation of glycerol in a flow reactor over a bifunctional Ni/WO3–TiO2 catalyst at 240–255 °C and hydrogen pressure of 3 MPa affords propan-1-ol and propan-2-ol in total yield of 94%.
- Greish, Alexander A.,Finashina, Elena D.,Tkachenko, Olga P.,Nikul'shin, Pavel A.,Ershov, Mikhail A.,Kustov, Leonid M.
-
-
Read Online
- TiO2/polymeric supported silver nanoparticles applied as superior nanocatalyst in reduction reactions
-
A novel polymeric nanocomposites (TiO2/poly(acrylamide-co-methylenbisacrylamide)) decorated with silver nanoparticles (Ag NPs) denoted as (Ag–TiO2/poly(AM-co-MBAM)) was prepared and fully characterized. Initially, the surface of TiO
- Sedghi, Roya,Asadi, Shima,Heidari, Bahareh,Heravi, Majid M.
-
-
Read Online
- Electrode Potential of a Dispersed Raney Nickel Electrode during Acetone Hydrogenation: Influence of the Solution and Reaction Kinetics
-
The hydrogenation of acetone was investigated in basic aquueous solutions with undoped and chromium-doped catalysts.The reaction was carried out under pressure in an autoclave equipped with a reference electrode.The consumption of hydrogen and the electrode potential were measured during the course of the reaction.A mathematical model was applied which fits the experimental kinetic data well.It allows the computation of the rate constant and the absorption equilibrium constants.The kinetics obey a Langmuir-Hinshelwood mechanism with competitive adsorption.The metallic catalyst particles behave like a dispersed electrode and an electrochemical double layers is formed at their surface.In the presence of hydrogen alone, the metal potential obeys the Nernst law for the hydrogen electrode.During acetone hydrogenation, the double layer is modified and the measured potential goes to the positive region for several tens of millivolts, depending on whether the catalyst is doped or not.In all cases an experimental correlation was found between this experimental potential rise and the reaction rate.
- Pardillos-Guindet, J.,Vidal, S.,Court, J.,Fouilloux, P.
-
-
Read Online
- CATALYTIC AND STOICHIOMETRIC REDUCTION OF KETONES AND ALDEHYDES BY THE HYDRIDOTETRACARBONYL FERRATE ANION
-
Acetone is catalytically reduced to isopropyl alcohol by carbon monoxide and water in the presence of iron carbonyls and triethylamine at 100 deg C and 100 bar.Use of NaOH in place of triethylamine gives a much less efficient catalyst system.The Et3NH*HFe(CO)4 system also catalyses the reduction of n-butyraldehyde to n-butyl alcohol at room temperature in a fast stoichiometric reaction, whereas NaHFe(CO)4 is inactive under the same conditions.The Et3NH+ cation is necessary for the transfer of a proton to the carbonyl group, while the HFe(CO)4- anion carries out nucleophilic attack on carbonyl group and supplies the hydride ion.
- Marko, Laszlo,Radhi, Mazin A.,Otvos, Irma
-
-
Read Online
- Synthesis, Characterization, Stability and Cytotoxic Evaluation of Novel Titanium(IV) Complexes of 8-Hydroxyquinoline and 2-Hydroxy-N-phenylbenzylamine Derivatives
-
A new class of moisture stable heteroleptic titanium(IV) complexes, synthesized from 8-hydroxyquinoline of the type [(Q)2Ti(2-O-5-XC6H3CH2NC6H4R] (3a-j), was prepared by reacting the antecedent molecule [(Q2)Ti(OiPr)2] (2) with various 2-hydroxy-N-phenyl-benzylamine analogues in 1:1 molar ratios in dry toluene (where, HQ = 8-hydroxyquinoline; iPr = isopropyl; R = H, 4-CH3, 4-OCH3, 2-Cl, 4-Cl, 2-Br, 4-Br; X= H, Br). Moisture sensitive study disclosed that these new metal complexes were unreacted for 72 h. Mass spectral data were employed for proving the mono-nuclearity of the new derivatives. Thermal decomposition pattern of the new derivatives was explained by thermogravimetric analyses. Elemental analyses data are in concordance with their expected values. The hexa-coordinated way of titanium-ligand linkage is further proved through NMR, FTIR, and UV-visible spectral studies. The cytotoxic efficiency of new complexes was tested against MDA-MB-231 human breast carcinoma cell line. Complex 3a exhibited the highest cytotoxic potential of 0.039 μM in comparison to all its analogues of this series by employing cisplatin as the standard.
- Samuel, Blassan,Pathak, Madhvesh
-
-
Read Online
- Catalytic reduction of acetophenone with transition metal systems containing chiral bis(oxazolines)
-
The catalytic behaviour of several Ru, Rh and Ir systems containing bis(oxazoline) ligands (1-6) has been tested in the asymmetric reduction of acetophenone (7) to give 1-phenylethanol (8) by hydrogenation (Ir systems), transfer hydrogenation (Ir and Ru s
- Gómez, Montserrat,Jansat, Susanna,Muller, Guillermo,Bonnet, Michel C,Breuzard, Jérémy A.J,Lemaire, Marc
-
-
Read Online
- Supramolecular nickel complex based on thiosemicarbazone. Synthesis, transfer hydrogenation and unexpected thermal behavior
-
The cationic thiosemicarbazone complex of nickel containing triphenylphosphine as coligand was synthesized through the isopropanol-assisted hydrogen transfer reaction. The thiosemicarbazone ligand (LH2) and its cationic nickel complex, [Ni(LH)(PPh3)]+Cl-·(CH3)2CHOH, were characterized by elemental analysis, IR, 1H NMR and UV-Vis spectroscopies. The molecular structure of the complex was also determined by single crystal X-ray diffraction technique. In addition computational studies at B3LYP/6-311G(d,p) (main group) and LANL2DZ (Ni) level were carried out for theoretical characterization of the ligand and complex. Structural analysis of the complex indicated the presence of square-planar coordination geometry (ONNP) about nickel in which the thiosemicarbazone ligand coordinated as mononegative tridentate. Isopropyl alcohol catalyzed efficiently the transfer hydrogenation and the cationic complex formed through inter conversion azinyl-azinylidene. All spectral data support the formation of the ligand and its nickel complex and the results calculated using theoretical methods coincide well with the experimental findings. The thermal degradation of the complex was investigated using thermogravimetric and differential thermal analyses techniques in nitrogen and oxygen atmosphere. The oxidative-thermal decomposition of the compound showed volatilization of nickel as unexpected behavior unlike nitrogen atmosphere.
- Güveli, ?ükriye,Bal-Demirci, Tülay,ülküseven, Bahri,?zdemir, NamIk
-
-
Read Online
- Engineered alkane-hydroxylating cytochrome P450BM3 exhibiting nativelike catalytic properties
-
(Figure Presented) Divide, evolve, and conquer: A domain-based strategy (see scheme) was used to engineer high catalytic and coupling efficiency for propane hydroxylation in a multidomain cytochrome P450 enzyme. The engineered enzymes exhibit high total activities in whole-cell bioconversions of propane to propanol under mild conditions, using air as oxidant.
- Fasan, Rudi,Chen, Mike M.,Crook, Nathan C.,Arnold, Frances H.
-
-
Read Online
- Hydration of Propene over Proton- and Metal Ion-Exchanged Zeolite Catalysts at Atmospheric Pressure
-
The gas-phase hydration of propene over proton-exchanged or metal ion-exchanged zeolites with various Si/Al ratios and structures (such as ZSM-5, mordenite, ferrierite, and Y-type) has been studied.It was found that the catalytic activity of proton-exchanged zeolites for the conversion of propene to 2-propanol did not depend on their framework structure, but showed a volcano-shaped dependence on the Al content, as was observed in the hydration of ethene.On the basis of temperature-programmed desorption experiments of NH3 adsorbed on the zeolites, it was confirmed that the activity is controlled by the acidity of the catalysts.The catalytic activity of metal ion-exchanged Y zeolites increased with an increase in the electronegativity of the metal ion.
- Mori, Hiroshi,Mizuno, Noritaka,Shirouzu, Toshihiro,Kagawa, Shuichi,Iwamoto, Masakazu
-
-
Read Online
- Synthesis of uniform titanium and 1:1 strontium-titanium carboxyhydrosols by controlled hydrolysis of alkoxymetal carboxylate precursors
-
Uniform inorganic carboxhydrosols containing titanium or strontium and titanium cations were precipitated from isopropyl alcohol solutions by the controlled hydrolysis of metal alkoxycarboxylate precursors. The hydrolysis of various triisopropoxytitanium carboxylate compounds yielded the capability to control particle size. Spherical particles of carboxyhydrosols were prepared in mean sizes from 0.4 to 2.9 μm. Controlled hydrolysis of quintaisopropoxystrontium titanium octanoate resulted in slightly agglomerated, uniform 1-μm spheres in a solvent medium in which controlled precipitation of uniform powders was not previously possible. Conversion of the hydrous oxide carboxylate precipitate to the oxide via calcination or hydrothermal treatment was possible.
- Riman,Landham,Bowen
-
-
Read Online
- An adsorption calorimetry study of the adsorption of acetone on raney nickel under conditions of liquid-phase hydrogenation
-
Adsorption calorimetry was used to study the characteristics of the adsorption of acetone on Raney nickel from 2-propanol-water solutions under conditions of liquid-phase hydrogenation. The isotherms of adsorption of acetone on Raney nickel and the dependences of integral and differential heats of adsorption on the adsorption value were obtained. It was established that the adsorption of acetone on Raney nickel occurs by the mechanism of volume filling of micropores in the pore space of the catalyst with adsorbate solution, which consists of partially or completely desolvated acetone molecules irrespective of the concentration of 2-propanol in the solvent. Nauka/Interperiodica 2006.
- Sharonov,Ulitin,Lukin
-
-
Read Online
- Propane reacts with O2 and H2 on gold supported TS-1 to form oxygenates with high selectivity
-
Gold nanoparticles supported on a microporous titanosilicate (TS-1) were found to be highly selective (95%) towards the formation of acetone and isopropanol from propane, O2, and H2 at moderate temperatures (443 K). The Royal Society of Chemistry.
- Bravo-Suarez,Bando,Akita,Fujitani,Fuhrer,Oyama
-
-
Read Online
- Hydrogenation of acetone on technetium catalysts
-
The catalytic properties of supported mono-and bimetallic catalysts of the Tc/support, M/support, and M-Tc/support types (M = Pt, Pd, Rh, Ru, Ni, Re, Co; supports are γ-Al2O3, MgO, SiO2) were investigated in the acetone hydrogenation. The main products of this reaction are isopropyl alcohol and propane. The catalytic activity in the acetone hydrogenation of the metals studied decreases in the consequence Pt > Tc ≈ Rh > Pd > Ru > Ni ≈ Re > Co (with γ-Al2O3 as the support). The influence of support nature on the catalytic activity was investigated for the Rh-Tc system as an example. A nonadditive increase in the catalytic activity of Rh-Tc/γ-Al203 in comparison with monometallic catalysts was found. The state of the surface of the catalysts was characterized by the UV-VIS diffuse reflectance spectra.
- Rimar,Pirogova
-
-
Read Online
- Effect of polyamide on selectivity of its supported Raney Ni catalyst
-
A newly-developed polyamide supported Raney Ni catalyst, which is suitable for use in fix-bed reactions with high selectivity, was studied in this paper. Selective hydrogenation of acetone to isopropanol was chosen as a probe reaction. It has been found that clean preparation of isopropanol could be achieved, that is to say, the two main byproducts (isopropyl ether and methyl- iso-butyl carbinol) could be eliminated with the newly-developed polyamide supported Raney Ni catalyst. The elimination of these side reactions was attributed to the adsorption effect of polyamide support and a model was proposed. The proposed model was further proved by hydroamination reaction of acetone. According to this model, catalyst support can play an important role in chemical reactions. Different products could be produced when different catalyst support is used, the main reaction and side reactions can even be reversed sometimes when the chemicals, active component of catalyst and reaction condition are the same. This model could help to improve catalytic selectivity of many Raney metal catalysts used routinely in chemical and oil refining industry, and is also useful for hydrogenation reactions in pharmaceutical and food industry.
- Jiang, Haibin,Lu, Shuliang,Zhang, Xiaohong,Tian, Baoliang,Peng, Hui,Dai, Wei,Qiao, Jinliang
-
-
Read Online
- EFFECT OF ISOTOPE SUBSTITUTION ON THE MAGNITUDE OF NONEQUILIBRIUM NUCLEAR POLARIZATION IN PHOTOLYSIS OF ACETONE IN METHANOL
-
Polarization of nuclei in both the products of the reactions and in the CHD2OD proton without polarization in the CH3OH protons is observed in irradiation of a solution of acetone in CD3OD in the presence of CHD2OD and CH3OH.Polarization of the protons of the products is strongly dependent on the temperature of the solution and arises in radical pairs; polarization of the proton of partially deuterated methyl alcohol is due to a mechanism of optical nuclear polarization.It was hypothesized that the isotope effect is due to a difference in proton and electron relaxation and to a difference in the rates of cross-relaxation transitions.
- Skakovskii, E. D.,Tychinskaya, L. Yu.,Rykov, S. V.,Yankelevich, A. Z.
-
-
Read Online
- Effect of Fluorination of the meso-Phenyl Groups on Selective Tetraphenylporphyrinatoiron(III)-catalysed Reactions of Propane with Molecular Oxygen
-
A series of tetrakis(pentafluorophenyl)iron(III) complexes are active catalysts for the selective air oxidation of propane to isopropyl alcohol and acetone under mild conditions, and provide hundreds of catalytic turnovers in the absence of any added co-reductants.
- Ellis, P. E. Jr.,Lyons, J. E.
-
-
Read Online
- Ruthenium carbonyl carboxylate complexes with nitrogen-containing ligands III. Catalytic activity in hydrogenation
-
Several mononuclear and dinuclear ruthenium carbonyl acetate complexes containing bipyridine or phenanthroline have been tested as catalysts in the hydrogenation of alkenes, alkynes and ketones.They are active in polar solvents and in water and the nitrogen-containing ligands are unaltered at the end of the hydrogenation.Keywords: Ruthenium; Carbonyl complexes; N-donors; Hydrogenation; Catalysis; Homogeneous
- Frediani, Piero,Bianchi, Mario,Salvini, Antonella,Guarducci, Roberto,Carluccio, Luciano C.,Piacenti, Franco
-
-
Read Online
- Mechanistic study of propane selective oxidation with H2 and O2 on Au/TS-1
-
The selective oxidation of propane to acetone and 2-propanol with H2 and O2 was studied on Au/TS-1 by kinetic and spectroscopic analysis. A kinetic study using a factorial design at conditions where the catalyst was stable and gave propane conversions of 90%, resulted in a power-rate law expression of the form roxyg. = koxyg.(H2)0.74(O2)0.36(C3H8)0.29. In situ Au L3-edge X-ray absorption near-edge spectroscopy (XANES) measurements showed activation of O2 on Au, whereas in situ ultraviolet-visible (UV-vis) spectroscopy evidenced the presence of Ti-hydroperoxo species. The role of the Ti-hydroperoxo species was probed by a transient technique in which changes in Ti K-edge XANES spectra were used to determine the evolution of coverage with time (d θ / d t). It was shown that the rate of reaction by XANES (6.7 × 10-4 s-1) was close to the turnover rate measured in a catalytic flow reactor (5.6 × 10-4 s-1), indicating that the hydroperoxo species were true intermediates in the reaction. A proposed reaction sequence in which H2O2 forms on Au sites and propane is partially oxidized on Ti centers accounts for the spectroscopic results and the reaction orders obtained experimentally for the power-rate law expression.
- Bravo-Suarez, Juan J.,Bando, Kyoko K.,Fujitani, Tadahiro,Oyama, S. Ted
-
-
Read Online
- The role played by acid and basic centers in the activity of biomimetic catalysts of the catalase, peroxidase, and monooxidase reactions
-
The acid-basic centers of heterogeneous carriers of catalase, peroxidase, and monooxigenase biomimetics, in particular, iron protoporphyrin deposited on active or neutral aluminum magnesium silicate, were studied. The catalytic activity of biomimetics was stabilized, which allowed us not only to synthesize fairly effective biomimetics but also to clarify certain details of the mechanism of their action and perform a comparative analysis of the functioning of biomimetics and the corresponding enzymes.
- Magerramov,Nagieva
-
-
Read Online
- Hydrogenolysis of 1,2-propanediol for the production of biopropanols from glycerol
-
Production of propanols from glycerol, which are known as biopropanols, requires catalysts for the hydrogenolysis of 1,2-propanediol, which has been easily derived from glycerol. It is found that the Rh/SiO2 catalysts modified with ReOx/s
- Amada, Yasushi,Koso, Shuichi,Nakagawa, Yoshinao,Tomishige, Keiichi
-
-
Read Online
- A Cross-Correlation Mechanism for the Formation of Spin Polarization
-
Photolysis of acetone in the presence of various hydrogen donors and of 3-hydroxy-3-methyl-2-butanone involves the formation of propan-2-olyl radicals which show both electron and nuclear spin polarization.The electron polarization of the radicals leads to additional nuclear polarization of the reaction products.Transfer of electron to nuclear polarization can occur by cross-relaxation and cross-correlation.The latter is descibed in detail.Experimentally, the mechanisms leads to a formation of net nuclear polarization for symmetrical radical pairs as well as an unusual kinetic behavior of multiplet effects.
- Tsentalovich, Yu. P.,Frantsev, A. A.,Doktorov, A. B.,Yurkovskaya, A. V.,Sagdeev, R. Z.
-
-
Read Online
- Gas-phase oxidation of propylene into acetone on a V2O5/TiO2 catalyst: Effect of pressure and role of water
-
The effect of pressure and role of water on gas-phase oxidation of propylene into acetone on a V2O5/TiO2 catalyst were investigated. A positive effect of increasing the pressure and water content in the reaction mixture in the oxidative conversion of propylene into acetone on a V2O5/TiO2 catalyst was observed. The results showed that the reaction occurred via intermediate formation of isopropanol, which was produced in situ as a result of the acid-catalyzed hydration of propylene and, under certain conditions, may be the main product.
- Chernov,Sobolev,Koltunov, K. Yu.
-
-
Read Online
- FORMULATION AND METHOD FOR SPRAY-DRYING D-TAGATOSE
-
A D-tagatose spray-drying feed formulation is a mixture of D-tagatose and a functional excipient co-dissolved in a solvent to produce a excipient/D-tagatose composite having a glass transition temperature of greater than 30° C. A method of spray-drying D-tagatose includes the steps of (a) preparing the D-tagatose spray-drying formulation, (b) atomizing the D-tagatose spray-drying formulation in a drying chamber containing a hot inert processing gas and evaporating droplets to produce solid particles of excipient/D-tagatose composite and (c) separating and collecting the solid particles of excipient/D-tagatose composite from the processing gas.
- -
-
-
- Time-Dependent Self-Assembly of Copper(II) Coordination Polymers and Tetranuclear Rings: Catalysts for Oxidative Functionalization of Saturated Hydrocarbons
-
This study describes a time-dependent self-assembly generation of new copper(II) coordination compounds from an aqueous-medium reaction mixture composed of copper(II) nitrate, H3bes biobuffer (N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid), ammonium hydroxide, and benzenecarboxylic acid, namely, 4-methoxybenzoic (Hfmba) or 4-chlorobenzoic (Hfcba) acid. Two products were isolated from each reaction, namely, 1D coordination polymers [Cu3(μ3-OH)2(μ-fmba)2(fmba)2(H2O)2]n (1) or [Cu2(μ-OH)2(μ-fcba)2]n (2) and discrete tetracopper(II) rings [Cu4(μ-Hbes)3(μ-H2bes)(μ-fmba)]·2H2O (3) or [Cu4(μ-Hbes)3(μ-H2bes)(μ-fcba)]·4H2O (4), respectively. These four compounds were obtained as microcrystalline air-stable solids and characterized by standard methods, including the single-crystal X-ray diffraction. The structures of 1 and 2 feature distinct types of metal-organic chains driven by the μ3- or μ-OH- ligands along with the μ-benzenecarboxylate linkers. The structures of 3 and 4 disclose the chairlike Cu4 rings assembled from four μ-bridging and chelating aminoalcoholate ligands along with μ-benzenecarboxylate moieties playing a core-stabilizing role. Catalytic activity of 1-4 was investigated in two model reactions, namely, (a) the mild oxidation of saturated hydrocarbons with hydrogen peroxide to form alcohols and ketones and (b) the mild carboxylation of alkanes with carbon monoxide, water, and peroxodisulfate to generate carboxylic acids. Cyclohexane and propane were used as model cyclic and gaseous alkanes, while the substrate scope also included cyclopentane, cycloheptane, and cyclooctane. Different reaction parameters were investigated, including an effect of the acid cocatalyst and various selectivity parameters. The obtained total product yields (up to 34% based on C3H8 or up to 47% based on C6H12) in the carboxylation of propane and cyclohexane are remarkable taking into account an inertness of these saturated hydrocarbons and low reaction temperatures (50-60 °C). Apart from notable catalytic activity, this study showcases a novel time-dependent synthetic strategy for the self-assembly of two different Cu(II) compounds from the same reaction mixture.
- Costa, Ines F. M.,Kirillova, Marina V.,André, Vania,Fernandes, Tiago A.,Kirillov, Alexander M.
-
supporting information
p. 14491 - 14503
(2021/07/19)
-
- A 3D MOF based on Adamantoid Tetracopper(II) and Aminophosphine Oxide Cages: Structural Features and Magnetic and Catalytic Properties
-
This work describes an unexpected generation of a new 3D metal-organic framework (MOF), [Cu4(μ-Cl)6(μ4-O)Cu(OH)2(μ-PTAO)4]n·2nCl-EtOH·2.5nH2O, from copper(II) chloride and 1,3,5-triaza-7-phosphaadamantane 7-oxide (PTAO). The obtained product is composed of diamandoid tetracopper(II) [Cu4(μ-Cl)6(μ4-O)] cages and monocopper(II) [Cu(OH)2] units that are assembled, via the diamandoid μ-PTAO linkers, into an intricate 3D net with an nbo topology. Magnetic susceptibility measurements on this MOF in the temperature range of 1.8-300 K reveal a ferromagnetic interaction (J = +20 cm-1) between the neighboring copper(II) ions. Single-point DFT calculations disclose a strong delocalization of the spin density over the tetranuclear unit. The magnitude of exchange coupling, predicted from the broken-symmetry DFT studies, is in good agreement with the experimental data. This copper(II) compound also acts as an active catalyst for the mild oxidation and carboxylation of alkanes. The present study provides a unique example of an MOF that is assembled from two different types of adamantoid Cu4 and PTAO cages, thus contributing to widening a diversity of functional metal-organic frameworks.
- ?liwa, Ewelina I.,Nesterov, Dmytro S.,Kirillova, Marina V.,K?ak, Julia,Kirillov, Alexander M.,Smoleński, Piotr
-
supporting information
p. 9631 - 9644
(2021/06/30)
-
- Chemoselective and Site-Selective Reductions Catalyzed by a Supramolecular Host and a Pyridine-Borane Cofactor
-
Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.
- Morimoto, Mariko,Cao, Wendy,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
-
supporting information
p. 2108 - 2114
(2021/02/06)
-
- Hydrogen-Catalyzed Acid Transformation for the Hydration of Alkenes and Epoxy Alkanes over Co-N Frustrated Lewis Pair Surfaces
-
Hydrogen (H2) is widely used as a reductant for many hydrogenation reactions; however, it has not been recognized as a catalyst for the acid transformation of active sites on solid surface. Here, we report the H2-promoted hydration of alkenes (such as styrenes and cyclic alkenes) and epoxy alkanes over single-atom Co-dispersed nitrogen-doped carbon (Co-NC) via a transformation mechanism of acid-base sites. Specifically, the specific catalytic activity and selectivity of Co-NC are superior to those of classical solid acids (acidic zeolites and resins) per micromole of acid, whereas the hydration catalysis does not take place under a nitrogen atmosphere. Detailed investigations indicate that H2 can be heterolyzed on the Co-N bond to form Hδ-Co-N-Hδ+ and then be converted into OHδ-Co-N-Hδ+ accompanied by H2 generation via a H2O-mediated path, which significantly reduces the activation energy for hydration reactions. This work not only provides a novel catalytic method for hydration reactions but also removes the conceptual barriers between hydrogenation and acid catalysis.
- Deng, Qiang,Deng, Shuguang,Gao, Ruijie,Li, Xiang,Tsang, Shik Chi Edman,Wang, Jun,Zeng, Zheling,Zou, Ji-Jun
-
p. 21294 - 21301
(2021/12/17)
-
- Hydrogenolysis of glycerol in an aqueous medium over Pt/WO3/zirconium phosphate catalysts studied by1H NMR spectroscopy
-
Bifunctional Pt/WO3/zirconium phosphate catalyzes the liquid-phase hydrogenolysis of glycerol in an aqueous medium.1H NMR spectroscopy (solvent suppression pulse program) is employed to monitor this reaction. Propanediols (1,3 + 1,2-PDO) formed as the major product along with propanols (1- and 2-POs) as the minor product. A synergistic enhancement in glycerol conversion and selectivity to 1,3-PDO was observed when both Pt and WO3were present in the catalyst. Avolcano-shapevariation of catalytic activity with W content was observed. A catalyst with 8 wt% W and 1 wt% Pt exhibited the highest selective hydrogenolysis performance (glycerol conversion = 92.3% and total PDOs selectivity = 45.9% and 1,3-PDO selectivity = 20.8% at 200 °C). Dispersed Pt in contact with polytungstate-type WO3species was found to be the active catalytic site.1H NMR spectroscopy is demonstrated as an attractive technique toquantifythe products of a glycerol hydrogenolysis reaction.
- Bhowmik, Susmita,Enjamuri, Nagasuresh,Darbha, Srinivas
-
p. 5013 - 5022
(2021/03/26)
-
- Hydrodeoxygenation of C4-C6 sugar alcohols to diols or mono-alcohols with the retention of the carbon chain over a silica-supported tungsten oxide-modified platinum catalyst
-
The hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over a Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of the C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in the hydrodeoxygenation of other polyols to some extent but much less active in that of mono-alcohols, at higher temperature (453 K), mono-alcohols can be produced from sugar alcohols. A good total yield (59%) of pentanols can be obtained from xylitol, which is mainly converted to C2 + C3 products in the literature hydrogenolysis systems. It can be applied to the hydrodeoxygenation of other sugar alcohols to mono-alcohols with high yields as well, such as erythritol to butanols (74%) and sorbitol to hexanols (59%) with very small amounts of C-C bond cleavage products. The active site is suggested to be the Pt-WOx interfacial site, which is supported by the reaction and characterization results (TEM and XAFS). WOx/SiO2 selectively catalyzed the dehydration of xylitol to 1,4-anhydroxylitol, whereas Pt-WOx/SiO2 promoted the transformation of xylitol to pentanols with 1,3,5-pentanetriol as the main intermediate. Pre-calcination of the reused catalyst at 573 K is important to prevent coke formation and to improve the reusability.
- Betchaku, Mii,Cao, Ji,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
-
p. 5665 - 5679
(2021/08/16)
-
- Facilitating Pt?WOx Species Interaction for Efficient Glycerol Hydrogenolysis to 1,3-Propanediol
-
Designing efficient catalysts for glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO), which involves the selective cleavage of the secondary C?O bond, is a challenging task. Current Pt?WOx-based catalysts often provide low atom efficiency of W and Pt toward 1,3-PDO production due to undesired catalyst structures. Herein, we fabricate the highly-dispersed substantially uniform WOx species on inert α-Al2O3 support by simple high-temperature heat-treatment, and the amount of Pt?WOx interface active sites could be adjusted by Pt loading, showing an excellent catalytic performance in glycerol hydrogenolysis at high concentration of glycerol, especially the unprecedented W efficiency (76 g1,3-PDOgW?1 h?1) toward 1,3-PDO. The high catalytic efficiency is attributed to the strong interaction between the isolated WO4 species and platinum, which could in-situ generate the Br?nsted acid sites during the reaction as evidenced by IR analysis with NH3 adsorption.
- Zhao, Binbin,Liang, Yu,Liu, Lei,He, Qian,Dong, Jin-Xiang
-
p. 3695 - 3705
(2021/07/02)
-
- Role of Ga3+promoter in the direct synthesis of iso-butanolviasyngas over a K-ZnO/ZnCr2O4catalyst
-
The direct synthesis of iso-butanol is an important reaction in syngas (composed of CO and H2) conversion. K-ZnO/ZnCr2O4(K-ZnCr) is a commonly used catalyst. Here, Ga3+is used as an effective promoter to boost the efficiency of the catalyst and retard the production of CO2. X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflection spectroscopy and electron microscopy were used to characterize the structural variations with different amounts of Ga3+, the results showed that the particle size of the catalyst decreases with the addition of Ga3+. The temperature-programmed desorption of NH3and CO2, and diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTs) analysis of the CO adsorption revealed that the acidity and basicity were altered owing to the different forms of Ga3+adoption. X-ray photoelectron spectroscopy and density functional theory (DFT) calculations revealed that the formation of Ga clusters that are coordinated on the exposed surfaces of ZnCr2O4, and undergo a tetra-coordinated Ga3+exchange with one of the Zn in ZnCr2O4(ZG) and ZnGa2O4, probably depends on the amount of Ga added. The structural evolution of the Ga3+promoted K-ZnO/ZnCr2O4catalysts can be described as follows: (i) the main forms are ZG and Ga coordinated ZnCr2O4, in which the amount of Ga3+is below 1.10 wt%; and (ii) the Ga3+containing compound is gradually changed from ZG to ZnGa2O4and the amount of gallium clusters increased when the amount of Ga3+was higher than 1.10 wt%. The catalytic performance evaluation results show that K-Ga1.10ZnCr exhibits the highest space time yield and selectivity of alcohols, in which the three compounds play different roles in syngas conversion: ZG is the main active site that boosts the efficiency of the catalysts, owing to the intensified CO adsorption and decreased activation energy of CHO formation through CO hydrogenation; ZnGa2O4only modifies the surface basicity and acidity on the catalyst, thereby impacting the carbon chain growth after the CO is adsorbed. The effects of Ga coordinated with ZnCr2O4shows little impact on the CO adsorption owing to the weak electron donating effects of Ga.
- Zhang, Tao,Zeng, Chunyang,Wu, Yingquan,Gong, Nana,Yang, Jiaqian,Yang, Guohui,Tsubaki, Noritatsu,Tan, Yisheng
-
p. 1077 - 1088
(2021/02/26)
-
- Chromium-Catalyzed Production of Diols From Olefins
-
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
- -
-
Paragraph 0111
(2021/03/19)
-
- Selectivity controlled transformation of carbon dioxide into a versatile bi-functional multi-carbon oxygenate using a physically mixed ruthenium-iridium catalyst
-
To mitigate environmental concern and energy issues, the conversion of carbon dioxide (CO2) to valuable and useful carbon chemicals offers a promising strategy for the development of a carbon neutral economy. The utilization of inert CO2as a building block in the synthesis of multi-carbon (>2) oxygenated compounds, specifically propylene glycol methyl ether (PGME; C4H10O2), produced annually at a multi-million-ton scale from petroleum-based propylene oxide is of particular interest because of its multifaceted industrial and commercial applications. Herein, we present a simple and straightforward system that uses CO2in compressed form as the C1 feedstock for the synthesis of PGME by direct hydrogenation and subsequent C-C coupling without any other sacrificial reagents. In addition, we combine experimental results with DFT calculations to elucidate the synergistic contributions of two catalytic metals (Ru and Ir) to activation of CO2for hydrogenation and consequent mediation of the C-C bond formation leading to the generation of PGME. Taken together, our findings suggest that the strategy presented herewith may serve as a starting point for the development of a sustainable chemical synthesis platform for multi-carbon oxygenates by utilizing CO2as the starting material.
- Chatterjee, Abhijit,Chatterjee, Maya,Kawanami, Hajime,Kitta, Mitsunori
-
p. 4719 - 4731
(2021/07/26)
-
- Efficient Conversion of Biomass Derived Levulinic Acid to γ-Valerolactone Using Hydrosilylation
-
Converting biomass into value-added chemicals is of significant interest and we report an efficient hydrosilylation to convert levulinic acid to γ-valerolactone using cost-effective silanes such as PMHS and TMDS with B(C6F5)3 as catalyst. This metal free methodology works at room temperature reaching TONs and TOFs up to 16000 and 2000 h?1. Insights into the reaction mechanism are reported.
- Garg, Nitish K.,Schmalz, Veronika,Johnson, Magnus T.,Wendt, Ola F.
-
supporting information
p. 5243 - 5247
(2021/10/19)
-
- Ultrastable Cu Catalyst for CO2 Electroreduction to Multicarbon Liquid Fuels by Tuning C–C Coupling with CuTi Subsurface
-
Production of multicarbon (C2+) liquid fuels is a challenging task for electrocatalytic CO2 reduction, mainly limited by the stabilization of reaction intermediates and their subsequent C?C couplings. In this work, we report a unique catalyst, the coordinatively unsaturated Cu sites on amorphous CuTi alloy (a-CuTi@Cu) toward electrocatalytic CO2 reduction to multicarbon (C2-4) liquid fuels. Remarkably, the electrocatalyst yields ethanol, acetone, and n-butanol as major products with a total C2-4 faradaic efficiency of about 49 % at ?0.8 V vs. reversible hydrogen electrode (RHE), which can be maintained for at least 3 months. Theoretical simulations and in situ characterization reveals that subsurface Ti atoms can increase the electron density of surface Cu sites and enhance the adsorption of *CO intermediate, which in turn reduces the energy barriers required for *CO dimerization and trimerization.
- Duan, Chongxiong,Duan, Delong,Hu, Fei,Jiang, Jun,Jiang, Yawen,Kong, Tingting,Liu, Qi,Long, Ran,Lv, Xuefeng,Wang, Xiaonong,Xiong, Yujie,Yang, Li,Zeng, Longjiao
-
supporting information
p. 26122 - 26127
(2021/11/12)
-
- AEROBIC ELECTROCATALYTIC OXIDATION OF HYDROCARBONS
-
This invention is directed to a method of oxygenating hydrocarbons with molecular oxygen, O2, as oxidant under electrochemical reducing conditions, using polyoxometalate compounds containing copper such as Q10 [Gu4(H2O)2(B-α-PW9O)2] or Q12{ [Cu(H2O)]3[(A-α- PW9O34)2(NO3)-] } or solvates thereof as catalysts, wherein Q are each independently selected from alkali metal cations, alkaline earth metal cations, transition metal cations, NH4+,H+ or any combination thereof.
- -
-
Paragraph 0074
(2022/01/04)
-
- Reviving electrocatalytic reductive amination: A sustainable route from biogenic levulinic acid to 1,5-dimethyl-2-pyrrolidone
-
The electrocatalytic reductive amination offers a green pathway to N-containing platform and fine chemicals by using water as a hydrogen source and benign reaction conditions. However, systematic studies about suitable reaction conditions and application to biogenic substrates are rare. Here, we present the electrochemical transformation of levulinic acid to 1,5-dimethyl-2-pyrrolidone. Data from Smirnov et al. for the amination of conventional ketones were validated and extended by systematically investigating the impact of electrode material, substrate concentration, current density, solvent, electrolyte, and pH value. High substrate concentrations in an aqueous electrolyte with a high pH value enable imine formation and copper is identified as the most selective cathode material at current densities lower than 40 mA cm-2. The application of optimized reaction conditions to levulinic acid, followed by a short heating procedure for dehydrative ring closure, led to 1,5-dimethyl-2-pyrrolidone in 78% yield. The systematic approach of this work presents the first example of an electrochemical levulinic acid amination and provides a methodology for the benign synthesis of other N-containing species. This journal is
- Holzh?user, F. Joschka,Kurig, Nils,Mürtz, Sonja D.,Palkovits, Regina
-
supporting information
p. 8428 - 8433
(2021/11/17)
-
- Green method for preparing isopropanol by catalytic distillation (by machine translation)
-
The invention relates to a method, for preparing isopropanol by catalytic distillation . in particular to a method for preparing isopropyl alcohol, by carrying out catalytic reaction, after mixing and preheating, raw materials into a fluidized bed reactor, continuously and stirring, to obtain a mesoporous framework metal hybrid catalyst, The method comprises the following steps: firstly, mixing and preheating the reactor, with acetone and hydrogen into a fluidized bed reactor to prepare a mesoporous framework metal hybrid catalyst, and drying, to obtain a high-purity isopropanol, product purity, obtained by further rectification in a fluidized bed reactor after being subjected to mixing and preheating, to, obtain a mesoporous framework metal hybrid ≥ 96.5%. catalyst . ≥ 99.2%. (by machine translation)
- -
-
Paragraph 0025-0070
(2020/04/29)
-
- Understanding the deactivation behavior of Pt/WO3/Al2O3 catalyst in the glycerol hydrogenolysis reaction
-
The selective hydrogenolysis of glycerol to 1,3-propanediol is a highly important reaction for both improving the profitability of biodiesel and valorization of biomass. While intensive research efforts have been devoted to enhancing the catalytic activity and selectivity, little is focused on the stability although the latter is of paramount importance to practical applications. In this work, we investigated the stability of Pt/WO3/Al2O3 and observed a continuous deactivation trend during a 700 h time-on-stream run. Neither the leaching of active W nor the coking was responsible for the deactivation. Instead, XRD, HAADF-STEM and CO chemisorption results clearly showed the occurrence of significant aggregation of Pt particles, which caused a remarkable decrease of Pt-WOx interfacial sites. As a consequence, strong Br?nsted acid sites which were in situ formed by H2 dissociation at the Pt-WOx interfacial sites were reduced, leading to the deactivation of the catalyst.
- Lei, Nian,Liu, Fei,Miao, Zhili,Pan, Xiaoli,Wang, Aiqin,Wang, Hua,Zhang, Tao
-
p. 1261 - 1267
(2020/03/13)
-
- One-pot synthesis of 1,3-butanediol by 1,4-anhydroerythritol hydrogenolysis over a tungsten-modified platinum on silica catalyst
-
Chemical production of 1,3-butanediol from biomass-derived compounds was first reported by 1,4-anhydroerythritol hydrogenolysis over a Pt-WOx/SiO2 catalyst. The reaction proceeded by ring opening hydrogenolysis of 1,4-anhydroerythritol followed by selective removal of secondary OH groups in 1,2,3-butanetriol, and an overall 1,3-butanediol yield up to 54% was then obtained. The performance of the Pt-WOx/SiO2 catalyst for 1,4-anhydroerythritol hydrogenolysis was closely correlated with that for glycerol hydrogenolysis to 1,3-propanediol. The optimized Pt-WOx/SiO2 (Pt: 4 wt% and W: 0.94 wt%) catalyst showed 57% yield of 1,3-propanediol.
- Asano, Takehiro,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
-
supporting information
p. 2375 - 2380
(2020/05/14)
-
- Discovering positively charged Pt for enhanced hydrogenolysis of glycerol to 1,3-propanediol
-
Atomically-dispersed Pt supported on WOx-modified tantalum oxide was developed as a highly active catalyst for selective hydrogenolysis of glycerol, with the productivity of 30.80 g gPt-1 h-1 toward 1,3-propanediol. The WOx species pre-deposited on T-Ta2O5 were found to assist the atomic dispersion of platinum. The WOx-stabilized Ptδ+ species adsorb hydrogen easily and facilitate the hydrogen heterolytic dissociation, which significantly enhances the capability of in situ generated Br?nsted acid sites and the hydrogenation activity. This provides a new strategy for developing bi-functional catalysts for a broad range of hydrogen and acid-involved reaction.
- Zhao, Binbin,Liang, Yu,Liu, Lei,He, Qian,Dong, Jinxiang
-
supporting information
p. 8254 - 8259
(2020/12/31)
-
- Direct Transformation of Glycerol to Propanal using Zirconium Phosphate-Supported Bimetallic Catalysts
-
Selective transformation of glycerol to propanal (PA) provides a feasible route towards the sustainable synthesis of high value-added chemicals. In this work, zirconium phosphate (ZrP) was studied as support and Ru and Co as metal sites for glycerol hydrogenolysis in a continuous-flow reactor. It was found that ZrP-supported Co?O species had a moderate selectivity to PA (49.5 %) in glycerol hydrogenolysis. Notably, once Ru species were doped into CoO/ZrP, the resulting catalyst exhibited not only an outstanding catalytic performance for glycerol hydrogenolysis to PA (a selectivity of 80.2 % at full conversion), but also a high stability at least a 50 h long-term performance. The spent catalyst could be regenerated by calcining in air to remove carbonaceous deposits. Characterization indicated that the acid sites on ZrP played a very critical role in the dehydration of glycerol into acrolein (AE), that the distribution of Co was uniform, basically consistent with that of Zr, P and Ru, and that an especially close contact between Co?O and Ru species was formed on Ru/CoO/ZrP catalyst. The further activity tests and characterizations confirmed that there was a strong interaction between the dispersed Co?O species and Ru0 nanoparticles, which endowed Ru sites with high electronic density. This effect could play a role in facilitating the dissociation of H2, and thus in promoting the hydrogenation reaction. Besides, DFT calculations suggested that the Co?O species can adsorb more strongly the C=C bond of the intermediate AE on a highly coordinatively unsaturated Co (Cocus) site and thus lead to preferential hydrogenation at the C=C bond of AE to PA.
- Gong, Honghui,Zhou, Chuan,Cui, Yan,Dai, Sheng,Zhao, Xiuge,Luo, Ruihan,An, Pengfei,Li, Huan,Wang, Haifeng,Hou, Zhenshan
-
p. 4954 - 4966
(2020/08/21)
-
- Solvent free three-component synthesis of 2,4,5-trisubstituted-1H-pyrrol-3-ol-type Compounds from L-tryptophan: DFT-B3LYP calculations for the reaction mechanism and 3H-pyrrol-3-one?1H-pyrrol-3-ol tautomeric equilibrium
-
In this paper, we describe the solvent-free three-component synthesis of 2,4,5-trisubstituted-1H-pyrrol-3-ol-type compounds from L-tryptophan. The first step of the synthetic methodology involved the esterification of L-tryptophan in excellent yields (93–98%). Equimolar mixtures of alkyl 2-aminoesters, 1,3-dicarbonyl compounds, and potassium hydroxide (0.1 eq.) were heated under solvent-free conditions. The title compounds were obtained in moderate to good yields (45%–81%). Density functional theory using “Becke, 3-parameter, Lee–Yang–Parr” correlational functional (DFT-B3LYP) calculations were performed to understand the molecular stability of the synthesized compounds and the tautomeric equilibrium from 3H-pyrrol-3-one type intermediates to 1H-pyrrol-3-ol type aromatized rings.
- Becerra, Lili Dahiana,Coy-Barrera, Ericsson,Quiroga, Diego
-
-
- Carbon‐supported Raney nickel catalyst for acetone hydrogenation with high selectivity
-
Catalysts with high selectivity play key roles in green chemistry. In this work, a granular Raney Ni catalyst using carbon as support (Raney Ni/C) was developed by mixing phenolic resin with Ni-Al alloy, conducting carbonization at high temperature, and leaching with alkaline liquor. The as-prepared Raney Ni/C catalyst is suitable for use in fix-bed reactors. Moreover, it shows high activity and selectivity for catalytic acetone hydrogenation. For instance, at the reaction temperature of 120°C, the conversion of acetone can reach up to 99.9% and the main byproduct methyl isobutylcarbinol (MIBC) content can be diminished to 0.02 wt%. The Raney Ni/C may represent a new type of shaped Raney metal catalysts, which are important fix-bed catalysts in chemical industry.
- Lu, Shuliang,Wu, Jiajia,Peng, Hui,Chen, Yong
-
supporting information
(2020/02/25)
-
- Insight into the nature of Br?nsted acidity of Pt-(WOx)n-H model catalysts in glycerol hydrogenolysis
-
In glycerol hydrogenolysis, the conventional preparation methods for Pt-WOx catalysts on active supports usually result in the coexistence of various active sites, causing complex reaction network and declining the atom efficiency of W toward 1
- Huang, Shouying,Li, Wei,Li, Ying,Ma, Xinbin,Wang, Shengping,Wang, Xiaofei,Wang, Yue,Yao, Dawei,Zhao, Yujun,Zhou, Wei
-
p. 154 - 163
(2020/06/01)
-
- The role of MPV reaction in the synthesis of propene from ethanol through the acetone route
-
Physical mixtures of AgCeO2 and ZrO2/SiO2 were employed in the ethanol conversion to propene in the presence of water through the acetone route. The oxides were characterized by XRD, N2 physical adsorption, isop
- Aguiar, E. Falabella S.,Matheus, C. R. V.
-
-
- Direct Catalytic Conversion of Ethanol to C5+ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability
-
Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd-promoted ZnO-ZrO2 catalyst. The sequence of reaction steps involved in the C5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross-aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. A yield of >70 percent to C5+ ketones was achieved over a 0.1 percent Pd-ZnO-ZrO2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.
- Bathena, Tanmayi,Goulas, Konstantinos A.,Gray, Michel,Guo, Mond F.,Kovarik, Libor,Martinez, Abraham,Ramasamy, Karthikeyan K.,Subramaniam, Senthil,Zhang, Xiao
-
p. 14550 - 14557
(2020/07/08)
-
- Olefin reaction in the catalyst and the olefin production
-
PROBLEM TO BE SOLVED: To provide a catalyst for obtaining an olefin in high selectivity with a vicinal diol as a raw material.SOLUTION: A catalyst for olefination reaction for use in a reaction to produce an olefin by a reaction of a polyol, having two adjacent carbon atoms each having a hydroxy group, with hydrogen comprises: a carrier; at least one oxide selected from the group consisting of oxides of the group 6 elements and oxides of the group 7 elements supported on the carrier; and at least one metal selected from the group consisting of silver, iridium, and gold supported on the carrier.SELECTED DRAWING: None
- -
-
Paragraph 0141-0143; 0145; 0149-0150
(2020/10/31)
-
- An active and stable multifunctional catalyst with defective UiO-66 as a support for Pd over the continuous catalytic conversion of acetone and hydrogen
-
The one-pot synthesis of methyl isobutyl ketone (MIBK) and methyl isobutyl methanol (MIBC) from acetone and hydrogen is a typical cascade reaction comprised of aldol condensation-dehydration-hydrogenation. Pd loss and aggregation during long term operation are typical problems in industrial application. In this paper, an active and stable catalyst was achieved with defective UiO-66 as a support for Pd, which was synthesized with the ratio 15?:?1 of ZrOCl2·8H2O to ZrCl4as Zr-precursors. The resultant Pd catalyst remained active for at least 1000 h with a MIBK + MIBC selectivity of 84.87-93.09% and acetone conversion of 45.26-53.22% in a continuous trickle-bed reactor. Besides the increased Br?nsted acid amount generated by the defect sites was favorable for the activity, the cavity confinement in the UiO-66 (R= 15?:?1) structure also efficiently prevented Pd loss and aggregation during the long term run. The contrast of the characterization of the fresh and used Pd/UiO-66 (R= 15?:?1) indicated that the deactivation of the catalyst was attributed to carbonaceous accumulation on the catalyst surface, which could be easily regenerated by calcination. This work supplied a new alternative for the design and utilization of industrial catalysts for MIBK and MIBC synthesis.
- Hu, Yingjie,Mei, Yuxin,Lin, Baining,Du, Xuhong,Xu, Fan,Xie, Huasheng,Wang, Kang,Zhou, Yonghua
-
-
- Covalently anchored chlorosulfonyl-calix[4]arene onto silica gel as an efficient and reusable heterogeneous system for reduction of ketones using NaBH4
-
The catalytic activities of chlorosulfonyl-calix[4]arene-bonded silica gel (CSC[4]A-SG) as a novel heterogeneous catalyst was illustrated by efficient reduction of various ketones to their corresponding alcohols. To illustrate the promoting effect of the
- Chenari, Ashkan Bagheri,Saber-Tehrani, Mandana,Mamaghani, Manouchehr,Nikpassand, Mohammad
-
-
- PROCESS FOR MAKING FORMIC ACID UTILIZING LOWER-BOILING FORMATE ESTERS
-
Disclosed is a process for recovering formic acid from a formate ester of a C3 to C4 alcohol. Disclosed is also a process for producing formic acid by carbonylating a C3 to C4 alcohol, hydrolyzing the formate ester of the alcohol, and recovering a formic acid product. The alcohol may be dried and returned to the reactor. The process enables a more energy efficient production of formic acid than the carbonylation of methanol to produce methyl formate.
- -
-
Paragraph 00182
(2019/02/15)
-
- Rapid transfer hydrogenation of acetophenone using ruthenium catalysts bearing commercially available and readily accessible nitrogen and phosphorous donor ligands
-
The screening, synthesis and testing of Ru complexes generated from commercially available ligands or ligands that can be synthesised in one step, is described. The catalysts were tested for activity in the transfer hydrogenation of acetophenone by isopropanol, a probe reaction for hydrogen transfer processes between oxygenated species, often found in applications such as biomass upgrading and fine and specialty chemical synthesis. Ligand screening was conducted by in situ catalyst generation and examined NPN and NNN pincer type ligands bearing N–H or C[dbnd]N functional groups. The most active transfer hydrogenation catalysts were found to be those bearing N–H functionality, either as amino groups or as benzimidazole groups. Well-defined catalyst precursors were subsequently synthesised, including the novel complex [Ru(1)PPh3(Cl)2] (where (1) = bis(3-aminopropyl)phenylphosphine), the first reported Ru complex for this NPN ligand. Established (PN)2 and PP/NN ketone hydrogenation catalysts were also screened for transfer hydrogen capability, of which [Ru(PhPN)2Cl2] (where PhPN = 2-(diphenylphosphino)ethylamine) was the most active. Subsequently, [Ru(1)PPh3(Cl)2], [Ru(PhPN)2Cl2] and [Ru(4)(PPh3)2Cl][Cl] (where (4) = 2,6-bis(2-benzimidazolyl)pyridine) were investigated more closely to compare rate constants (determined by reaction profile regression analysis) as a more accurate measure of catalyst activity over commonly reported turn over frequencies (TOF). The effect of the reaction products on the catalyst activity was evaluated using feed spiking experiments. Catalyst deactivation was shown to be prevalent and subsequently incorporated into a simple kinetic model which enabled more accurate reaction profile fitting and provided rate constants for both the transfer hydrogenation step and deactivation reaction.
- Braden, Drew J.,Cariou, Renan,Shabaker, John W.,Taylor, Russell A.
-
p. 367 - 375
(2018/12/13)
-
- Effective Hydrogenolysis of Glycerol to 1,3-Propanediol over Metal-Acid Concerted Pt/WOx/Al2O3 Catalysts
-
Selective cleavage of secondary C?O bond is an important yet challenging strategy in glycerol valorization, and the product 1,3-propanediol (1,3-PDO) is of great value in polyester industry. Herein, we report a series of Pt/WOx/Al2O3 catalysts for selective hydrogenolysis of glycerol in a fixed-bed reactor and obtain the highest space-time yield of 1,3-PDO (191.7*10?3 g1,3-PDO h?1 g?1 cat.) to date. Both Pt and W have substantial effects on the 1,3-PDO yield with the optimum Pt/W atomic ratio of 1/2～1/4. Spectroscopy characterizations as well as chemisorption experiments reveal that at the medium domain size of WOx, hydrogen spillover can take place to the greatest extent due to the improved dispersion of Pt and the suitable reducibility of WOx. Dehydration/dehydrogenation tests of 2-butanol suggest that strong Br?nsted acid sites are created via hydrogen dissociation at the Pt?WOx interface and spillover to the neighboring oxygen atom. Such in situ formed protons are critical to the selective cleavage of secondary C?O bonds of polyols.
- Lei, Nian,Zhao, Xiaochen,Hou, Baolin,Yang, Man,Zhou, Maoxiang,Liu, Fei,Wang, Aiqin,Zhang, Tao
-
supporting information
p. 3903 - 3912
(2019/07/18)
-
- Selective Hydrogenolysis of Glycerol to 1,3-Propanediol over Rhenium-Oxide-Modified Iridium Nanoparticles Coating Rutile Titania Support
-
The effect of support in Ir-ReOx catalysts for glycerol hydrogenolysis to 1,3-propanediol was investigated. Rutile TiO2 support showed high activity, even higher than previously reported SiO2 support. Anatase TiO2, C, ZrO2, CeO2, Al2O3, and MgO supports showed very low activity of supported Ir-ReOx pairs. Higher Ir-based 1,3-propanediol productivity of Ir-ReOx/rutile catalyst was obtained at the initial stage even with lower Re/Ir ratio (typical Ir loading amount, 4 wt %, nominal ratio of 0.25; actual ratio of 0.24) without addition of H2SO4 than that of Ir-ReOx/SiO2. The 1,3-propanediol productivity over Ir-ReOx catalysts showed dependency on catalyst compositions (metal loading amount), and the relationship between catalyst structure and activity was further established over Ir-ReOx/rutile. Relatively high Ir loading amount in comparison with small surface area (6 wt %, on 6 m2 g-1 rutile TiO2) showed the highest activity (Ir-based activity). From combined characterization results altogether (TPR, TEM, XPS, XAS, CO adsorption, CO FT-IR) with a kinetics study, the Ir metal particles interacted with the partially oxidized ReOx cluster (average valence of Re: +3) almost totally covering the surface of rutile TiO2 particles, and the active site was the Ir-ReOx interface. Small amounts of Ir species were incompletely reduced; however, such IrOx species as well as rutile TiO2 support were not directly involved in glycerol hydrogenolysis. The role of rutile support was regarded as providing a unique environment for stabilization of uniform and small Ir-ReOx particles with very high surface density on rutile TiO2, which increased the number of active sites per Re amount.
- Liu, Lujie,Asano, Takehiro,Nakagawa, Yoshinao,Tamura, Masazumi,Okumura, Kazu,Tomishige, Keiichi
-
p. 10913 - 10930
(2019/11/19)
-
- Interface synergy between IrOx and H-ZSM-5 in selective C–O hydrogenolysis of glycerol toward 1,3-propanediol
-
Site-selective deoxygenation of hydroxyl groups represents essential processes to access valuable functionalized bio-based compounds with industrial potential. One of the challenging tasks in this context is to convert biodiesel-derived glycerol in the presence of abundant water directly to 1,3-propanediol (1,3-PDO), a key component of the emerging polymer industry. Herein, a monometallic iridium supported on H-ZSM-5 in the absence of Re oxophilic metal oxides was prepared via grinding-assisted impregnation procedures and attempted as an effective and recyclable catalyst for the aqueous-phase selective hydrogenolysis of glycerol toward 1,3-PDO in the absence of acid additives. The results revealed the necessity to control the Ir domain dispersions, Ir0/Ir3+ ratio and the amounts of overall acid/Br?nsted acid sites. Activity depended linearly on the amount of overall and Br?nsted acid sites, and 1,3-PDO selectivity increased in the presence of Ir-induced Br?nsted acid sites, denoted as Ir-O(H)-H-ZSM-5. We speculate that Ir-O(H)-H-ZSM-5 are generated by the interfacial synergistic interaction between IrOx and H-ZSM-5 through hydrogen spillover and reverse hydrogen spillover according to the reported literatures. The reaction mechanism to elucidate the role of Ir-O(H)-H-ZSM-5 sites in glycerol hydrogenolysis was also postulated based on extensive characterization and catalytic reaction results.
- Wan, Xiaoyue,Zhang, Qi,Zhu, Mingming,Zhao, Yi,Liu, Yongmei,Zhou, Chunmei,Yang, Yanhui,Cao, Yong
-
p. 339 - 350
(2019/07/03)
-
- Direct Catalytic Methanol-to-Ethanol Photo-conversion via Methyl Carbene
-
A photo-driven direct methanol-to-ethanol conversion is reported with a robust gallium nitride catalyst under ambient conditions. This conversion is achieved with no solvent, ligand, additive, heating, atmosphere, or pressurization—just with light irradiation. A methyl carbene reaction intermediate is observed during the conversion, and the method enables access to the more useful (as both fuel and starting material) renewable resource ethanol. As an important effort to secure the sustainable “fossil alternative,” the direct conversion of the more readily available methanol to the more user-friendly, less toxic, and broadly applicable ethanol poses exciting potential as well as a tremendous scientific challenge. Herein, we report the first photo-driven one-step conversion of methanol to ethanol at ambient temperature, catalyzed by an ultra-stable gallium nitride semiconductor. Mechanistic studies revealed that methyl carbene (methylene), one of the most fascinating C1 building blocks in synthetic chemistry, was generated as a reaction intermediate, which potentially enables a green and novel method for generating carbene. We also found that methanol can be converted to n-propyl alcohol with the same catalyst through a simple change in reaction temperature, giving a unique selectivity and a high-value-added product. Methanol is an easily accessible fossil fuel alternative, but it is classified as hazardous and is also generally less valuable than other sources of carbon. A direct conversion of methanol to ethanol would provide facile access to a renewable starting material for applications as a safer fuel or an intermediate for the synthesis of the most demanded plastic, polyethylene (PE). This article reports the chemical transformation of methanol to ethanol and other higher alcohols, enabled by sp3-C–H methylation. In addition, the underlying chemistry can also be of importance for biochemistry and pharmaceutical chemistry, where methylation plays a pivotal role. The methanol-to-ethanol conversion is achieved in the presence of a robust catalyst and in only one step. No additive, solvent, or hazardous material is required.
- Liu, Mingxin,Wang, Yichen,Kong, Xianghua,Rashid, Roksana T.,Chu, Sheng,Li, Chen-Chen,Hearne, Zo?,Guo, Hong,Mi, Zetian,Li, Chao-Jun
-
supporting information
p. 858 - 867
(2019/04/10)
-
- Production of propylene glycol (1,2-propanediol) by the hydrogenolysis of glycerol in a fixed-bed downflow tubular reactor over a highly effective Cu-Zn bifunctional catalyst: Effect of an acidic/basic support
-
In this study, different acidic (V2O5, ZrO2, and TiO2) and basic (CaO and MgO) oxide-supported copper-zinc bimetallic catalysts were prepared by a deposition-precipitation method, and they were evaluated for the vapor-phase hydrogenolysis of glycerol to propylene glycol at 0.1 MPa and at 220 °C. The catalysts were thoroughly characterized by different techniques such as BET, XRD, H2-TPR, NH3 and CO2 TPD, N2O adsorptive decomposition, TEM, XPS, FE-SEM and TGA. Among all the supported catalysts, the Cu-Zn/MgO catalyst was found to be the most selective to propylene glycol. High copper-metal dispersion (～5%), surface area (～23 m2 g-1), the highest basicity (0.25 mmol CO2 g cat-1) and the availability of partially reduced copper species (Cu2O, CuO and Cu0) were the primary reasons for the higher propylene glycol selectivity. At optimum reaction conditions, i.e., at 220 °C, 0.72 MPa and a weight hourly space velocity (WHSV) of 0.073 h-1, ～98.5% conversion of glycerol with ～89% selectivity to propylene glycol was obtained over the Cu-Zn/MgO catalyst. This catalyst was also found to be stable for a long period of time (84 h) without much deactivation and without decrease in the selectivity to propylene glycol.
- Pandey, Dinesh Kumar,Biswas, Prakash
-
p. 10073 - 10086
(2019/07/03)
-
- Degradation of tri(2-chloroisopropyl) phosphate by the UV/H2O2 system: Kinetics, mechanisms and toxicity evaluation
-
A photodegradation technology based on the combination of ultraviolet radiation with H2O2 (UV/H2O2) for degrading tri(chloroisopropyl) phosphate (TCPP) was developed. In ultrapure water, a pseudo-first order reaction was observed, and the degradation rate constant reached 0.0035 min?1 (R2 = 0.9871) for 5 mg L?1 TCPP using 250 W UV light irradiation with 50 mg L?1 H2O2. In detail, the yield rates of Cl? and PO43? reached 0.19 mg L?1 and 0.58 mg L?1, respectively. The total organic carbon (TOC) removal rate was 43.02%. The pH value of the TCPP solution after the reaction was 3.46. The mass spectrometric detection data showed a partial transformation of TCPP into a series of hydroxylated and dechlorinated products. Based on the luminescent bacteria experimental data, the toxicity of TCPP products increased obviously as the reaction proceeded. In conclusion, degradation of high concentration TCPP in UV/H2O2 systems may result in more toxic substances, but its potential application for real wastewater is promising in the future after appropriate optimization, domestication and evaluation.
- He, Huan,Ji, Qiuyi,Gao, Zhanqi,Yang, Shaogui,Sun, Cheng,Li, Shiyin,Zhang, Limin
-
-
- Selective CO2 Electroreduction to Ethylene and Multicarbon Alcohols via Electrolyte-Driven Nanostructuring
-
Production of multicarbon products (C2+) from CO2 electroreduction reaction (CO2RR) is highly desirable for storing renewable energy and reducing carbon emission. The electrochemical synthesis of CO2RR catalysts that are highly selective for C2+ products via electrolyte-driven nanostructuring is presented. Nanostructured Cu catalysts synthesized in the presence of specific anions selectively convert CO2 into ethylene and multicarbon alcohols in aqueous 0.1 m KHCO3 solution, with the iodine-modified catalyst displaying the highest Faradaic efficiency of 80 % and a partial geometric current density of ca. 31.2 mA cm?2 for C2+ products at ?0.9 V vs. RHE. Operando X-ray absorption spectroscopy and quasi in situ X-ray photoelectron spectroscopy measurements revealed that the high C2+ selectivity of these nanostructured Cu catalysts can be attributed to the highly roughened surface morphology induced by the synthesis, presence of subsurface oxygen and Cu+ species, and the adsorbed halides.
- Gao, Dunfeng,Sinev, Ilya,Scholten, Fabian,Arán-Ais, Rosa M.,Divins, Nuria J.,Kvashnina, Kristina,Timoshenko, Janis,Roldan Cuenya, Beatriz
-
supporting information
p. 17047 - 17053
(2019/11/13)
-
- Reconstitution of full-length P450BM3 with an artificial metal complex by utilising the transpeptidase Sortase A
-
Haem substitution is an effective approach to tweak the function of haemoproteins. Herein, we report a facile haem substitution method for self-sufficient cytochrome P450BM3 (CYP102A1) from Bacillus megaterium utilising the transpeptidase Sortase A from Staphylococcus aureus. We successfully constructed Mn-substituted BM3 and investigated its catalytic activity.
- Omura, Keita,Aiba, Yuichiro,Onoda, Hiroki,Stanfield, Joshua Kyle,Ariyasu, Shinya,Sugimoto, Hiroshi,Shiro, Yoshitsugu,Shoji, Osami,Watanabe, Yoshihito
-
p. 7892 - 7895
(2018/07/25)
-
- PROCESS FOR PRODUCING DIISOPROPYL ETHER FROM HIGH PURITY PROPYLENE
-
A process for the production of diisopropyl ether from high purity propylene without the need of a propane-propylene fractionation column has been developed. The process involves (1) reacting a high purity propylene feedstock and water to produce isopropyl alcohol in a reactor and reacting the isopropyl alcohol with propylene to produce diisopropyl ether in the presence of an acidic ion exchange resin catalyst and a C4 diluent to generate a reactor effluent stream containing at least water, isopropyl alcohol, diisopropyl ether, propylene, and acid, (2) passing the reactor effluent to an acid removal zone to produce an acid-depleted stream, (3) dividing the acid-depleted stream into two portions, (4) recycling a portion to the reactor (5) purging a portion to prevent propane build-up and (6) recovering product diisopropyl alcohol.
- -
-
Paragraph 0025; 0028
(2018/07/15)
-
- Insights into the role of nanoalloy surface compositions toward catalytic acetone hydrogenation
-
A significant composition-dependent catalysis behavior was observed in catalytic acetone hydrogenation. Carbon supported PtRu alloy nanoparticles (NPs) with optimal surface composition achieved ultra-efficient and highly selective production of isopropyl alcohol.
- Yang, Zhao,Zhu, Huaze,Zhu, Huijuan,Wang, Yanbing,Che, Liming,Yang, Zhiqing,Fang, Jun,Wu, Qi-Hui,Chen, Bing Hui
-
supporting information
p. 8351 - 8354
(2018/08/04)
-
- Comparative study of WCX-based catalysts for aqueous phase hydrogenolysis of glycerol into bioadditives
-
Hydrogenolysis of glycerol has been a subject of intensive research in recent decades. Great efforts have been made investigating the mechanism of bond cleavage using metal or metallic oxide catalysts. In this work, effects of a series of WCx-based catalysts, including WCx, Cu/WCx, Pt/WCx, Ru/WCx, CuRu/WCx and CuPt/WCx, were studied on hydrogenolysis of glycerol to investigate the role of each active phase. WO3-Based catalysts were employed as a comparison with the WCx-based catalysts. Hydrogenolysis of model compounds (1,2-PDO and EG) of glycerol was also studied using these catalysts, in attempts to determine the mechanism of the whole reaction. The presence of metal elements on WCx or WO3 can significantly improve the conversion of reactant. In addition, the ability of WCx to promote cleavage of C-C was verified. Ru is more beneficial for formation of EG than Pt, whereas Pt is favorable for formation of 1,2-PDO. It had been supposed that hydrogenolysis of glycerol by WCx-based catalysts occurred via two different but overlapping routes: WCx-related reactions caused by C-C cleavage and metal-related reactions caused by C-O cleavage, which happen simultaneously in the reaction. The current study not only demonstrates that the catalytic performance of WCx can be manipulated by varying metal loading, but also offers a possible mechanism for C-C and C-O cleavage in hydrogenolysis of glycerol, which could be beneficial when focusing on the target product.
- Wei, Lingfei,Bibi, Rehana,Tian, Wei,Chen, Lingyu,Zheng, Yu,Li, Naixu,Zhou, Jiancheng
-
p. 3633 - 3641
(2018/03/06)
-
- Glycerol hydrogenolysis to n-propanol over Zr-Al composite oxide-supported Pt catalysts
-
Zr-Al mixed oxide supported Pt catalysts with different Zr/Al mole ratios (2.5%Pt/ZrxAl1–xOy) were synthesized by an impregnation method and used for the selective hydrogenolysis of glycerol to n-propanol in an autoclave reactor. The catalysts were fully characterized by X-ray powder diffraction, Brunauer-Emmett-Teller surface area analysis, CO chemisorption, H2 temperature- programmed reduction, pyridine-infrared spectroscopy, and NH3-temperature-programmed desorption. The results revealed that the Zr/Al ratio on the support significantly affected the size of the platinum particles and the properties of the acid sites on the catalysts. The catalytic performance was well correlated with the acidic properties of the catalyst; specifically, more acid sites contributed to the conversion and strong acid sites with a specific intensity contributed to the deep dehydration of glycerol to form n-propanol. Among the tested catalysts, 2.5 wt% Pt/Zr0.7Al0.3Oy exhibited excellent selectivity for n-propanol with 81.2% glycerol conversion at 240 °C and 6.0 MPa H2 pressure when 10% aqueous glycerol solution was used as the substrate. In addition, the effect of various reaction parameters, such as H2 content, reaction temperature, reaction time, and number of experimental cycles were studied to determine the optimized reaction conditions and to evaluate the stability of the catalyst.
- Li, Chuang,He, Bo,Ling, Yu,Tsang, Chi-Wing,Liang, Changhai
-
p. 1121 - 1128
(2018/05/29)
-
- Understanding the promotional effect of Au on Pt/WO3 in hydrogenolysis of glycerol to 1,3-propanediol
-
Pt/Au/WO3 bimetallic catalysts were prepared by impregnation of Pt onto preformed Au/WO3, obtained by a hexadecyl trmethyl ammonium bromide (CTAB)-assisted one-pot synthesis method. The resulting Pt/Au/WO3 catalysts exhibited remarkable synergistic effects for selective hydrogenolysis of glycerol to 1,3-propanediol. The characterization results showed that doping of Au promoted the reduction of both Pt and W at low temperatures and uniform dispersion of Pt on the WO3 support. Furthermore, more low-valence Pt species were produced on the WO3 surface after introduction of Au. These changes in electronic properties resulted in enhancement of both glycerol conversion and selectivity for 1,3-propanediol.
- Yang, Chaojun,Zhang, Fan,Lei, Nian,Yang, Man,Liu, Fei,Miao, Zhili,Sun, Yongnan,Zhao, Xiaochen,Wang, Aiqin
-
p. 1366 - 1372
(2018/07/13)
-
- Exploring the Reaction Pathways of Bioglycerol Hydrodeoxygenation to Propene over Molybdena-Based Catalysts
-
The one-step reaction of glycerol with hydrogen to form propene selectively is a particularly challenging catalytic pathway that has not yet been explored thoroughly. Molybdena-based catalysts are active and selective to C?O bond scission; propene is the only product in the gas phase under the standard reaction conditions, and further hydrogenation to propane is impeded. Within this context, this work focuses on the exploration of the reaction pathways and the investigation of various parameters that affect the catalytic performance, such as the role of hydrogen on the product distribution and the effect of the catalyst pretreatment step. Under a hydrogen atmosphere, propene is produced primarily via 2-propenol, whereas under an inert atmosphere propanal and glycerol dissociation products are formed mainly. The reaction most likely proceeds through a reverse Mars–van Krevelen mechanism as partially reduced Mo species drive the reaction to the formation of the desired product.
- Zacharopoulou, Vasiliki,Vasiliadou, Efterpi S.,Lemonidou, Angeliki A.
-
p. 264 - 275
(2017/12/15)
-
- Copper promoter effect on acid-base and redox sites of Fe/Al2O3 catalysts and their role in ethanol-acetone mixture conversion
-
Active species of copper and iron oxide (Cu-Fe) catalysts supported on alumina were prepared by combining Pechini and wet impregnation methods. The effect of combined acid-base and redox sites of Cu and Fe species on gas-phase ethanol-acetone mixture conversion was investigated. The catalysts were characterized by chemical analyses, XRD, H2-TPR, M?ssbauer spectroscopy, N2 physisorption, CO2-TPD, SEM-EDS, TG/DTA and pyridine adsorption isotherms. N2 adsorption/desorption isotherms and SEM-EDS analysis showed that the addition of copper caused an increase of BET surface area and Cu and Fe oxide dispersion. H2-TPR characterization showed that interactions between Cu and Fe oxides shift the reducibility of Fe3+ species to lower temperature improving the redox properties of the catalyst. The partial reduction of the Cu and Fe oxide species was found to be efficient in inhibiting the side decomposition reactions, improving the catalytic efficiency towards dehydrogenation and hydrogen transfer processes. It was found that acid-base pairs play an important role in the formation of dehydrogenation, dehydration and condensation products from ethanol, while redox sites are decisive for hydrogen transfer reactions with reduction of acetone to isopropanol. H2-TPR and M?ssbauer spectroscopy results for the spent catalysts revealed that the highest catalytic performance of the Cu-FeAl catalysts may be attributed to the good dispersion of the Cu oxide and the site generated by the partial reduction which produces Cu+/Cu0 and Fe2+ active species. A reaction pathway with the participation of the acid-base and redox sites in the formation of products by consecutive dehydrogenation-condensation or dehydrogenation-hydrogenation reactions has been proposed.
- Pinheiro, Antonio Narcisio,Dos Santos, Regina Claudia Rodrigues,Ferreira Dos Santos, Sarah Brenda,Da Silva Júnior, Moacir José,Pinheiro Braga, Tiago,Freire, Valder Nogueira,Valentini, Antoninho
-
p. 443 - 458
(2018/02/07)
-
- Carbon nanotube-supported copper-cobalt catalyst for the production of higher carbon number alcohols through carbon monoxide hydrogenation
-
A series of carbon nanotube (CNTs)-supported copper-cobalt catalysts were prepared and investigated in a slurry reactor for their ability to selectively convert syngas into higher carbon number alcohols. The 7.5Cu7.5Co/CNTs catalyst achieved superior selectivity towards the formation of ethanol (30.1percent) and C2+ alcohols (57.7percent), while the 10Co5Cu/CNTs catalyst exhibited the largest alcohol space-time yield (372.9 mg gcat-1 h-1). However, the pure Cu (15Cu/CNTs) catalyst displayed negligible activity. Cobalt reduction was enhanced in the presence of copper. In addition to the Cu0-Co0 center, Co0-Co2+ also presented dual active sites for higher alcohols synthesis, the Co2+ site could terminate carbon chain growth to produce alcohols. The ratio of Cu/Co considerably influences the metal particle properties-synergistically effecting the active species.
- Wang, Peng,Du, Xihua,Zhuang, Wenchang,Cai, Keying,Li, Jing,Xu, Yan,Zhou, Yingmei,Sun, Kai,Chen, Shuyao,Li, Xiaoli,Tan, Yisheng
-
p. 1373 - 1381
(2018/06/12)
-
- Revised Mechanisms for Aldehyde Disproportionation and the Related Reactions of the Shvo Catalyst
-
It is widely believed that the Shvo catalyst (1) dissociates to form two active species in solution: the 18-electron hydride RuH(CO)2[η5-C5(OH)Ph4] (2) and the naked 16-electron complex Ru(CO)2[η4-C5(=O)Ph4] (3). This combined experimental/computational study demonstrates that a sustained presence of 3 is not viable in the reactions of alcohols and organic carbonyls; thus, 3 is better treated as nonexistent under the typical catalytic conditions. We propose a modified view where the key catalytic species are the hydride 2 and the 18-electron metal alkoxide intermediate Ru(OR)(CO)2[η5-C5(OH)Ph4] existing in equilibrium with the corresponding alcohol complex. An X-ray crystallographic study of 2 revealed an interesting dihydrogen-bonded dimer structure in the solid state. The mechanistic ideas of this paper explain the highly efficient Tishchenko-like aldehyde disproportionation reaction with the Shvo catalyst. Additionally, our observations explain why 1 is inefficient for hydrogenation of ethyl acetate and for the acceptorless dehydrogenative coupling of ethanol. Our findings provide practical guidance for future catalyst design on the basis of the Shvo ruthenium dimer prototype.
- Gusev, Dmitry G.,Spasyuk, Denis M.
-
p. 6851 - 6861
(2018/06/25)
-
