67-64-1

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• Atomically precise silver clusters for efficient chlorocarbon degradation
• We describe the degradation of chlorocarbons (CCl4, C 6H5CH2Cl and CHCl3) in solution at room temperature (27 ± 4 °C) by the monolayer-protected silver quantum cluster, Ag9MSA7 (MSA: mercaptosuccinic acid) in the presence of isopropyl alcohol (IPA). The main degradation products were silver chloride and amorphous carbon. Benzyl chloride was less reactive towards clusters than CCl4 and CHCl3. Materials used in the reactions and the reaction products were characterized using several spectroscopic and microscopic tools such as ultraviolet-visible (UV/Vis) absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive analysis of X-rays (EDAX) and scanning electron microscopy (SEM). We have shown that clusters are more efficient for the degradation of halocarbons than the corresponding monolayer-protected nanoparticles (Ag@MSA, particle diameter 15 ± 5 nm) at a given time and temperature. The higher reactivity of clusters is attributed to their small size and large surface area. Clusters and nanoparticles were used for reactions in supported (on neutral alumina) and unsupported forms. A possible mechanism for the reaction has been postulated on the basis of experimental results.
• Bootharaju,Deepesh,Udayabhaskararao,Pradeep

• p. 611 - 620

  (2013)
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• EVIDENCE SUPPORTING A SINGLE ELECTRON TRANSFER PATHWAY IN THE REDUCTION OF AROMATIC KETONES BY METAL ALKOXIDES. LITHIUM ISOPROPOXIDE, AN EXCELLENT REDUCING AGENT FOR AROMATIC KETONES.
• Reactions of various metal alkoxides with aromatic ketones have been shown to produce radical intermediates.Lithium isopropoxide has been found to be an excellent reducing agent for aromatic ketones and reduces benzophenone at a faster rate than does aluminum isopropoxide.
• Ashby, E. C.,Goel, Anil B.,Argyropoulos, John N.

• p. 2273 - 2276

  (1982)
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• Transfer hydrogenation with abnormal dicarbene rhodium(iii) complexes containing ancillary and modular poly-pyridine ligands
• Treatment of an abnormal dicarbene ligated rhodium(iii) dimer with 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2′:6′,2′′-terpyridine (terpy) results in coordination of the N-donor ligands and concomitant cleavage of the dimeric structure. Depending on the denticity of the pyridyl ligand, this situation retains one (L = terpy) or two (L = bipy, phen) flexible sites for substrate coordination. In the case of the bipy complexes, modification of the electron density at Rh, without directly affecting the steric environment about the metal centre, was achieved by the incorporation of electron-donating or electron-withdrawing substituents on the bipy backbone. The dicarbene pyridyl complexes were active in transfer hydrogenation catalysis of benzophenone at 0.15 mol% catalyst loading in a iPrOH/KOH mixture. The catalysts displayed a strong characteristic colour change (yellow to purple) after activation which allowed for visual monitoring of the status of the reaction. The colour probe and the robustness of the active catalysts proved useful for catalyst recycling. The catalytic activity sustained over five consecutive substrate batch additions and gave a maximum overall turnover number of 3100.
• Farrell, Kevin,Melle, Philipp,Gossage, Robert A.,Müller-Bunz, Helge,Albrecht, Martin

• p. 4570 - 4579

  (2016)
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• Energy-storing Photocatalysis of Transition Metal Complexes with High Quantum Efficiency
• A tin(II)-co-ordinated iridium complex catalyst exhibited the highest photoreactivity ever reported for the energy-storing reaction of propan-2-ol dehydrogenation, with quantum efficiency and even 'photo-thermal energy conversion efficiency' exceeding unity.
• Yamakawa, Tetsu,Miyake, Hiroto,Moriyama, Hiroshi,Shinoda, Sumio,Saito, Yasukazu

• p. 326 - 327

  (1986)
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• Conversion of ethanol over supported cobalt oxide catalysts
• Conversion of ethanol was investigated on supported (ceria, zirconia and ceria-zirconia) cobalt oxide catalysts. The catalysts were prepared by support impregnation with cobalt nitrate-citric acid solution and they were explored by comparing results from different characterization techniques: X-ray fluorescence, X-ray diffraction, Raman spectroscopy and nitrogen adsorption techniques. Their catalytic properties at 693 K were characterized in a fixed-bed reactor. The CoOx/CeO2 catalyst displayed the highest catalytic activity. The conversion of ethanol decreased with the increase of the ZrO2/CeO2 ratio in the support of catalyst. All catalysts exhibited high selectivity of ethanol conversion to hydrogen and acetone. The coking of catalysts under reaction conditions was also characterized by gravimetric method. The results indicated that the increase of the ZrO2/CeO2 ratio in the support exerts significant influence on the coke formation. The amount of carbon deposited on CoO x/ZrO2 at 693 K was higher than on any other catalyst. Raman studies of used catalysts proved that their surface was almost completely covered with carbonaceous deposit, which was probably the main reason of deactivation of catalysts under reaction conditions.
• Rybak,Tomaszewska,MacHocki,Grzegorczyk,Denis

• p. 14 - 20

  (2011)
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• Catalytic effect of cuprous ions on the thermal decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane in methanol solution
• Thermal decomposition of 3,3,6,6-tetramethyl-1,2,4,5-tetraoxane was examined in methanol solution (1.69×10-2 M) containing cuprous ions (5.05×10-7 M) in the temperature range from 130 to 166°C using UV spectroscopy as analytical method. The ion-catalyzed reaction follows first-order kinetics with respect to the peroxide and added cuprous ions. The temperature effect on the rate of thermal decomposition of the title compound was described by the corresponding Arrhenius equations, and its stability in solution was estimated on a quantitative level. The activation parameters of the initial step of decomposition of 3,3,6,6-tetramethyl-1,2,4,5- tetraoxane were determined (ΔH≠ = 14.7±0.8 kcal mol-1; ΔS≠ = -38.9±1.4 cal mol -1 K-1; ΔG ≠ = 31.0±0.8 kcal mol-1). Electron-transfer mechanism was proposed for the reaction under study.
• Gimenez,Romero,Bustillo,Jorge,Gomez Vara,Castro

• p. 1273 - 1276

  (2008)
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• Rate constant for the reaction of CH3C(O)CH2 radical with HBr and its thermochemical implication
• The fast flow method with laser induced fluorescence detection of CH 3C(O)CH2 was employed to obtain the rate constant of k1 (298 K) = (1.83 ± 0.12 (1σ)) × 1010 cm3 mol-1 s-1 for the reaction CH 3C(O)CH2 + HBr ? CH3C(O)CH3 + Br (1, -1). The observed reduced reactivity compared with n-alkyl or alkoxyl radicals can be attributed to the partial resonance stabilization of the acetonyl radical. An application of k1 in a third law estimation provides Δf H298O (CH 3C(O)CH2) values of -24 kJ mol-1 and -28 kJ mol-1 depending on the rate constants available for reaction (- 1) from the literature.
• Farkas, Edit,Kovacs, Gergely,Szilagyi, Istvan,Dobe, Sandor,Berces, Tibor,Marta, Ferenc

• p. 32 - 37

  (2006)
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• Comparison N-CU–codoped nanotitania and n-doped nanotitania in photocatalytic reduction of CO2under UV light
• Nitrogen-copper–codoped nanotitania and nitrogen-doped nanotitania for CO2 photoreduction by water in liquid phase were prepared by sol-gel method. The catalysts were characterized by XRD, HRTEM, DRS, FTIR, and XPS. N-doped TiO2 have remarkably better photocatalytic activity than N- and Cu-codoped TiO2 for the CO2 photoreduction to acetone under ultraviolet illumination. The acetone yield of N3/TiO2 could reach 52.6 μmol/g h and the acetone yield of Cu0.6N4/TiO2 could reach 33.2 μmol/g h under UV conditions. The mechanism of CO2photoreduction on N-doped nanotitania and N-Cu–codoped TiO2was proposed.
• Liu, Cuiping,Yua, Tao,Tan, Xin,Huang, Xiang

• p. 9 - 14

  (2017)
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• CHANGE IN THE RATE OF DECOMPOSITION OF DIOXETANES IN SULFOLANE SOLUTIONS IN THE TRANSITION FROM THE LIQUID TO THE SOLID PHASE
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• Sharipov, G. L.,Ostakhov, S. S.,Voloshin, A. I.,Lotnik, S. V.,Kazakov, V. P.,Tolstikov, G. A.

• p. 2012 - 2016

  (1988)
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• A Thermokinetic Foundation for Oscillatory Phenomena in Gaseous Organic Oxidations under Well Stirred Flowing Conditions
• An experimental and theoretical attack on the fundamentals of thermokinetic phenomena associated with the gaseous, non-isothermal oxidation of hydrocarbons and other organic substrates is described.Quantitative comparisons are made between numerical modelling and experimental measurements under well stirred flowing conditions.Two chemical systems are considered, involving reactions of methyl radicals.These are: (i) di-t-butyl peroxide decomposition in nitrogen and (ii) di-t-butyl peroxide decomposition in an excess of oxygen.Simplified kinetic mechanisms for each of these systems are described and numerical computations for non-isothermal reactions are discussed.Stationary states and two different types of oscillatory modes are predicted to exist within limited ranges of p, Ta and composition, and these match experimental measurements quite satisfactorily.The integral role played by self heating in termokinetic oscillations is demonstrated and relationships to cool-flame phenomena are outlined.
• Griffiths, John F.,Hasko, Stephen M.,Shaw, Nigel K.,Torrez-Mujica, Tomas

• p. 343 - 354

  (1985)
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• Cooley

• (1938)
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• Kinetics of the Oxidation of 2-Hydroxy-2-methylpropanoic Acid by Silver(II) Ions Complexed with 2,2'-Bipyridine in Aqueous Nitrate Media
• Stopped-flow traces show that the oxidation of 2-hydroxy-2-methylpropionic acid (hmpa) by 2+ proceeds in two consecutive reactions.Both are found to be first order in II> and first order in .The first rapid reaction is ascribed to complex formation between AgII and hmpa and the second to a slower redox step.A mechanism is proposed to account for the observed orders in II>, and +> for each reaction and values for the enthalpies and entropies of activation are determined.To investigate the effect on the redox kinetics of oxidatively inert species close to the cation, these are compared with the transition-state parameters for the oxidation of hmpa by aqua-metal cations and for the oxidation of other substrates by metal cations complexed with 2,2'-bipyridine.
• Heyward, Malcolm P.,Wells, Cecil F.

• p. 1057 - 1070

  (1985)
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• Ketonization of Acetophenone Enol in Aqueous Buffer Solutions. Rate-Equilibrium Relations and Mechanism of the "Uncatalyzed" Reaction
• Rates of ketonization of acetophenone enol, generated by photohydration of phenylacetylene and Norrish type II photoelimination of γ-hydroxybutyrophenone, were measured at 25 deg C in aqueous buffer solutions of six carboxylic acids, six phosphonic acid monoanions, phosphoric acid, and dihydrogen phosphate.Analysis of the carboxylic acid data produced catalytic coefficients from which linear Broensted correlations were constructed, with α = 0.50 for ketonization of the enol and α = 0.32 for the more rapid ketonization of the enolate ion.A more extended, curved Broensted correlation for ketonization of the enolate ion was constructed by combining the carboxylic acid results with catalytic coefficients for the phosphonic acid monoanions, and analysis of this by Marcus theory gave the intrinsic barrier ΔG0+ = 12 kcal mol-1 and the work terms wτ = 2 kcal mol-1 and wp = 4 kcal mol-1.These results differ from the much smaller intrinsic barrier and strongly disparate work terms obtained previously in a similar study of isobutyrophenone enol, and an explanation of the difference in terms of a looser transition state (Kreevoy τ = 0.30) for the isobutyrophenone system is offered.Evidence is also supplied which indicates that the so-called "uncatalyzed" ketonization reaction occurs by a stepwise route rather than by a cyclic single-step mechanism.
• Chiang, Y.,Kresge, A. J.,Santaballa, J. A.,Wirz, J.

• p. 5506 - 5510

  (1988)
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• A Composite Ru-Pt Catalyst for 2-Propanol Dehydrogenation Adoptable to the Chemical Heat Pump System
• Synergetic promotion was observed for 2-propanol dehydrogenation with a composite Ru-Pt/carbon catalyst prepared by NaBH4 reduction of mixed metal chlorides adsorbed on active carbon in an aqueous solution.Metal crystallites were less than 2 nm in size.The pronounced rate is promising as the catalyst for the heat pump system.
• Ito, Eri,Yamashita, Masaru,Hagiwara, Shigeji,Saito, Yasukazu

• p. 351 - 354

  (1991)
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• Gas-Phase Chemiluminescence Study of Chemically Activated Tetramethyl-1,2-dioxetane Formed from the Reaction of O2(1Δg) with 2,3-Dimethyl-2-butene
• Chemically activated tetramethyl-1,2-dioxetane has been prepared by the reaction of O2(1Δg) with 2,3-dimethyl-2-butene at temperatures of 450 to 775 K and a pressure of 0.25 Torr.The observed product of the reaction was excited 1n?*(S1) acetone, which was identified by chemiluminescence spectra of the acetone (S1 -> S0) transition.Neither acetone (Ti) nor any other excited states were observed under the above conditions.The temperature dependence of the chemiluminescence gave an activation energy for the cycloaddition reaction of 8610 +/- 200 (1?) cal/mol.The quantum yield for acetone (S1) was 4 * 10-3 per reactive collision; its (1?) error is estimated as +/- a factor of 3.Chemiluminescence spectra taken at O2(3Σ1g) partial pressures greater than 2 Torr showed formaldehyde (S1 -> S0) bands.This is attributed to the well-known hydrocarbon "cool flame" mechanism, due to the presence of methyl radical formed by the thermal decomposition, in two steps, of 2,3-dimethyl-3-hydroperoxy-1-butene, another product path for the title reaction.This is the first report on the chemically activated decomposition of tetramethyl-1,2-dioxetane.
• Bogan, Denis J.,Lee, Dong-Heon

• p. 9304 - 9310

  (1992)
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• ZEOLITE-SUPPORTED TETRAMETHYL-1,2-DIOXETANE: NEW PATHWAYS TO CHEMILUMINESCENCE
• The thermal decomposition of tetramethyl-1,2-dioxetane (TMD) sorbed into zeolite Y containing Eu(3+) ions and 2,2'-bipyridine (samples abbreviated as ZYEBT) has been investigated.Decomposition of TMD yields, by energy transfer processes, chemiluminescence (CL) characteristic of the Eu(3+) ion.At loading levels corresponding to an upper-limit average of 0.5, 1.0, and 2.0 TMD molecules per unit cell, the CL decay curves are nonexponential at short times; at longer times, roughly exponential curves are characterized by a unimolecular rate constant k.Analyses of the long-time decays based on an Arrhenius expression for the rate constant provide evidence for a kinetic compensation effect: plots of log k vs. the activation energy Ea as a function of TMD loading level are linear.Solution data (benzene, benzonitrile) fall on the same line, suggesting that TMD decomposes by a common rate-limiting mechanism in these various environments.The Arrhenius parameters (Ea and the pre-exponential factor A) are smaller than the solution values and increase with TMD loading.When TMD is sorbed to the extent of an upper-limit average of ca. 7 molecules per unit cell, CL decay curves are initially nearly flat and then show an increase in decomposition rate with time.Mechanistic implications of these results are discussed.
• Benedict, Bryan L.,Ellis, Arthur B.

• p. 1625 - 1634

  (1987)
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• Heterogeneous hydrogenation catalyses over recyclable Pd(0) nanoparticle catalysts stabilized by PAMAM-SBA-15 organic-inorganic hybrid composites
• Pd(0) nanoparticle catalysts stabilized by Gn-PAMAM-SBA-15 (n = 1-4) organic-inorganic hybrid composites were successfully prepared. Heterogeneous hydrogenation reaction of allyl alcohol over the Pd(0)-Gn-PAMAM-SBA-15 catalysts showed their high activities with TOFs of 2185, 2266, 711, and 739 and selectivities of 79.0, 82.0, 93.4, and 91.4%, respectively. The activity over the Pd(0)-G4-PAMAM-SBA-15 catalyst was 1.5 times that over the fourth generation PAMAM encapsulated Pd(0) homogeneous catalyst. These catalysts can be easily recovered, reused multiple times, and preserved for one month in the air, maintaining high catalytic efficiencies. Copyright
• Jiang, Yijun,Gao, Qiuming

• p. 716 - 717

  (2006)
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• Reaction of Arylmethanes and Heteroarylmethanes with the tert-Butoxy Radical
• The relative rates of hydrogen atom abstraction from a series of 13 homoaryl- and heteroarylmethanes by the tert-butoxy radical were determined at 70 deg C.The attacking radical was photochemically generated from di-tert-butyl peroxide.A relatively small range of relative rates (factor of 7) has been found among the compounds studied; however, significant position variation among isomers is noted.The relative reactivities of the homoaryl- and heteroarylmethanes can be correlated with various calculated energy differences obtained from both HMO and standard semiempirical SCF-MO methods.Fairly good correlations were obtained by use of a carbocation model for the transition state (correlation coefficient 0.92).Much poorer correlations were obtained when a radical model was used for the transition state with either the HMO or SCF-MO approach (maximum correlation coefficient 0.49).This suggests that considerable charge development must be associated with the transition state of this reaction.
• Mahiou, Belaid,Gleicher, Gerald Jay

• p. 1555 - 1559

  (1987)
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• Cleavage of the carbon-carbon bond in α-glycols under the action of bismuth(v) derivatives
• Di(tert-butylperoxy)triphenylbismuth and the triphenylbismuth - tert-butyl hydroperoxide system react with 2,3-dimethylbutane-2,3-diol, benzopinacol, butane-2,3-diol, and ethane-1,2-diol with the cleavage of the C - C bond of α-glycol to form carbonyl compounds. Both heterolytic (through formation of cyclic triphenylbismuth glycolate) and homolytic cleavage occur.
• Dolganova,Dodonov,Zinov'eva,Prezhbog

• p. 1164 - 1166

  (1997)
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• Kinetics of the reaction between dimethyldioxirane and 2-methylbutane
• The kinetics of the reaction between dimethyldioxirane and 2-methylbutane in acetone solutions were studied spectrophotometrically at 25°C. The radical-chain induced decomposition of dioxirane proceeding with the participation of the carbon-centered radicals follows the first-order kinetic law. The reaction is inhibited by dioxygen. In the presence of O2, the dimethyldioxirane consumption is due to the homolysis of the O-O bond (at a rate constant of 6.3·10-4 s-1) followed by attack of the C-H bond of 2-methylbutane by the biradical formed. The rate constant of the reaction between the alkyl radical and dimethyldioxirane was estimated.
• Kazakov,Khusnullina,Kabal'nova,Khursan,Shereshovets

• p. 1690 - 1693

  (1997)
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• Aerobic oxidation of pinacol by vanadium(V) dipicolinate complexes: Evidence for reduction to vanadium(III)
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• Hanson, Susan K.,Tom Baker, R.,Gordon, John C.,Sutton, Andrew D.,Thorn, David L.,Scott, Brian L.

• p. 428 - 429

  (2009)
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• Binuclear iron complexes with acyclic Schiff bases based on 4-tert-butyl-2,6-diformylphenol: Synthesis, properties, and use in catalytic partial oxidation of isobutane
• New binuclear iron complexes with acyclic Schiff bases based on 4-tert-butyl-2,6-diformylphenol and amino acids methionine and histidine were synthesized. The composition and inferred structure of the complexes were studied by elemental analysis, IR spectroscopy, Moessbauer spectroscopy, and electrochemical methods. The synthesized complexes were studied in catalytic reactions of partial oxidation of isobutane to tert-butyl alcohol and decomposition of tert-butyl hydroperoxide. The activity and selectivity of the complex depend on the nature of the bridging group between two iron ions and are independent of the amino acid environment.
• Rodionova,Borisova,Smirnov,Ordomsky,Moiseeva,Pankratov

• p. 1201 - 1209

  (2013)
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• Acetic Acid Ketonization over Fe3O4/SiO2 for Pyrolysis Bio-Oil Upgrading
• A family of silica-supported, magnetite nanoparticle catalysts was synthesised and investigated for continuous-flow acetic acid ketonisation as a model pyrolysis bio-oil upgrading reaction. The physico-chemical properties of Fe3O4/SiO2 catalysts were characterised by using high-resolution transmission electron microscopy, X-ray absorption spectroscopy, X-ray photo-electron spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis and porosimetry. The acid site densities were inversely proportional to the Fe3O4 particle size, although the acid strength and Lewis character were size-invariant, and correlated with the specific activity for the vapour-phase acetic ketonisation to acetone. A constant activation energy (～110 kJ mol?1), turnover frequency (～13 h?1) and selectivity to acetone of 60 % were observed for ketonisation across the catalyst series, which implies that Fe3O4 is the principal active component of Red Mud waste.
• Bennett, James A.,Parlett, Christopher M. A.,Isaacs, Mark A.,Durndell, Lee J.,Olivi, Luca,Lee, Adam F.,Wilson, Karen

• p. 1648 - 1654

  (2017)
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• Kinetics and mechanism of the thermal decomposition reaction of acetone cyclic diperoxide in methyl tert-butyl ether solution
• The thermal decomposition reaction of acetone cyclic diperoxide (3,3,6,6-tetramethyl-1,2,4,5-tetroxane, ACDP), in the temperature range of 130.0-166.0°C and initial concentrations of range 0.4-3.1 × 10-2 mol kg-1 has been studied in methyl t-butyl ether solution. The thermolysis follows first-order kinetic laws up to at least ca 60% ACDP conversion. Under the experimental conditions, the activation parameters of the initial step of the reaction (ΔH# = 33.6 ± 1.1 kcal mol-1; ΔS# = -4.1 ± 0.7 cal mol-1 K-1; ΔG# = 35.0 ± 1.1. kcal mol-1) and acetone, as the only organic product, support a stepwise reaction mechanism with the homolytic rupture of one of its peroxidic bond. Also, participation of solvent molecules in the reaction is postulated given an intermediate diradical, which further decomposes by C-O bond ruptures, yielding a stoichiometric amount of acetone (2 mol per mole of ACDP decomposed). The results are compared with those obtained for the above diperoxide thermolysis in other solvents.
• Leiva, Laura C.,Jorge, Nelly L.,Romero, Jorge M.,Cafferata, Lazaro F.R.,Gomez Vara, Manuel E.

• p. 302 - 307

  (2004)
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• Kinetics and mechanism of the sonolytic destruction of methyl tert- butyl ether by ultrasonic irradiation in the presence of ozone
• The kinetics and mechanism of the sonolytic degradation of methyl tert- butyl ether (MTBE) have been investigated at an ultrasonic frequency of 205 kHz and power of 200 W L-1. The observed first-order degradation rate constant for the loss of MTBE increased from 4.1 x 10-4 s-1 to 8.5 x 10- 4 s-1 as the concentration of MTBE decreased from 1.0 to 0.01 mM. In the presence of O3, the sonolytic rate of destruction of MTBE was accelerated substantially. The rate of MTBE sonolysis with ozone was enhanced by a factor of 1.5-3.9 depending on the initial concentration of MTBE. tert-Butyl formate, tert-butyl alcohol, methyl acetate, and acetone were found to be the primary intermediates and byproducts of the degradation reaction with yields of 8, 5, 3, and 12%, respectively. A reaction mechanism involving three parallel pathways that include the direct pyrolytic decomposition of MTBE, the direct reaction of MTBE with ozone, and the reaction of MTBE with hydroxyl radical is proposed. The kinetics and mechanism of the sonolytic degradation of methyl tert-butyl ether (MTBE) have been investigated at an ultrasonic frequency of 205 kHz and power of 200 W L-1. The observed first-order degradation rate constant for the loss of MTBE increased from 4.1 × 10-4 s-1 to 8.5 × 10-4 s-1 as the concentration of MTBE decreased from 1.0 to 0.01 mM. In the presence of O3, the sonolytic rate of destruction of MTBE was accelerated substantially. The rate of MTBE sonolysis with ozone was enhanced by a factor of 1.5-3.9 depending on the initial concentration of MTBE. tert-Butyl formate, tert-butyl alcohol, methyl acetate, and acetone were found to be the primary intermediates and byproducts of the degradation reaction with yields of 8, 5, 3, and 12%, respectively. A reaction mechanism involving three parallel pathways that include the direct pyrolytic decomposition of MTBE, the direct reaction of MTBE with ozone, and the reaction of MTBE with hydroxyl radical is proposed.
• Kang, Joon-Wun,Hoffmann, Michael R.

• p. 3194 - 3199

  (1998)
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• The Selective Oxidation of Primary Alcohols to Aldehydes by O2 Employing a Trinuclear Ruthenium Carboxylate Catalyst
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• Bilgrien, Carl,Davis, Shannon,Drago, Russell S

• p. 3786 - 3787

  (1987)
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• Zirconia catalysed acetic acid ketonisation for pre-treatment of biomass fast pyrolysis vapours
• Crude pyrolysis bio-oil contains significant quantities of carboxylic acids which limit its utility as a biofuel. Vapour phase ketonisation of organic acids contained within biomass fast-pyrolysis vapours offers a potential pre-treatment to improve the stability and energy content of resulting bio-oils formed upon condensation. Zirconia is a promising catalyst for such reactions, however little is known regarding the impact of thermal processing on the physicochemical properties of zirconia in the context of it's corresponding reactivity for the vapour phase ketonisation of acetic acid. Here we show that calcination progressively transforms amorphous Zr(OH)4 into small tetragonal ZrO2 crystallites at 400 °C, and subsequently larger monoclinic crystallites >600 °C. These phase transitions are accompanied by an increase in the density of Lewis acid sites, and concomitant decrease in their acid strength, attributed to surface dehydroxylation and anion vacancy formation. Weak Lewis acid sites (and/or resulting acid-base pairs) are identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C, with stronger Lewis acid sites favouring competing unselective reactions and carbon laydown. Acetone selectivity is independent of acid strength.
• Jahangiri, Hessam,Osatiashtiani, Amin,Bennett, James A.,Isaacs, Mark A.,Gu, Sai,Lee, Adam F.,Wilson, Karen

• p. 1134 - 1141

  (2018)
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• Thermal decomposition of tert-butyl peroxide in a gas chromatographic reactor: A comparison of kinetic approaches
• The thermal decomposition of tert-butyl peroxide is investigated utilizing both the column and the injection port of a commercial gas chromatograph (GC) as chemical reactors. Using the injector liner as the reactor, the chromatographic peak areas of the reactant, measured at various injector temperatures, are used in the determination of the activation energy of the decomposition (Ea). With the column serving as the reactor, both the reactant peak areas and the product peak shapes are similarly utilized for this purpose. Values of Ea obtained using different mathematical treatments for each of the three approaches are found to range from 115 to 164 kJ/mol. Of these methods, the column reactor approach utilizing peak area measurements (referred to as PACR, for "peak area, column reactor") is found to be far superior in terms of its speed, robustness, and its accuracy in determining Ea. The PACR method's effectiveness can be largely attributed to the mathematical treatment that is described in the approach.
• Skrdla, Peter J.

• p. 386 - 393

  (2004)
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• Aldol condensation of acetic acid and formaldehyde to acrylic acid over a hydrothermally treated silica gel-supported B-P-V-W oxide
• Supported on silica B-P-V-W-Ox catalysts of the aldol condensation process, subjected to hydrothermal treatment (HTT), were synthesized and characterized. It was found that HTT of silica has a significant effect on catalyst texture, namely specific surface area, pore size. These properties affect the distribution of the active phase on the support surface. It was suggested that this is the reason of change in acid-base characteristics of the catalysts. It was observed that HTT at 100?150 °C leads to increase in surface, available for the reagents, ability to sorb acetic acid, decrease of acidity, improving catalytic activity and selectivity. It had been demonstrated that HTT allows to increase acrylic acid yield up to 67.6 % which is 10 % higher compared to that for catalyst supported on initial silica. The HTT of silica support before the active phase deposition is suggested as a cheap and efficient way to improve catalytic performance of B-P-V-W-Ox/SiO2 catalysts.
• Khalameida, S.,Khyzhun, O.,Kubitska, I.,Nebesnyi, R.,Pavliuk, A.,Pikh, Z.,Sydorchuk, V.,Voronchak, T.

• (2020)
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• Unpromoted and K2O-Promoted Cobalt Molybdate as Catalysts for the Decomposition of Acetic Acid
• Unpromoted cobalt molybdate was prepared from Co(NO3) 2 · 6H2O and (NH4)6Mo 7O24 · 4H2O, then calcined between 350 and 600°C for 5 h. K2O (10 w%), as a promoter, was added to the calcined sample at 350°C from two different sources (i.e. KOH and KNO 3) and was subjected to further calcination at 350°C for 5 h. The catalytic activity of unpromoted catalysts towards the vapour phase decomposition of CH3COOH was greatly influenced by the increase in the calcination temperature. This is attributed to the diminution of both S BET and their dual acidic-basic characters. The promoted sample from the KOH source was found to be the most active of the catalysts studied. This is due to its high population of both acidic-basic surface sites and the formation of two new phases. XRD and FTIR analyses of the used catalysts, after the decomposition reaction of acetic acid, showed a remarkable change in its structure compared with the parent samples.
• Halawy, Samih A.

• p. 371 - 380

  (2003)
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• Reaction Mechanism of 2-Propanol Dehydrogenation with a Carbon-Supported Ru-Pt Composite Catalyst in the Liquid Phase
• The reaction mechanism of dehydrogenation of 2-propanol substrates with and without deuterium-substitution with the Ru-Pt/carbon catalyst was studied to obtain strategies for catalyst designing suitable to direct 2-propanol fuel cells (D2PFC) and the catalyst-assisted chemical heat pump system. The Ru-Pt/carbon composite catalyst gave kinetic isotope effects of 1.54 and 1.96 for dehydrogenation at 82.4°C from (CH3)2CHOD and (CH3)2CDOH, respectively, which were contrasted to the corresponding magnitudes of 1.69 and 1.57 with a Ru/carbon catalyst and those of 1.13 and 1.81 with a Pt/carbon catalyst. The rate constants of dehydrogenation as a function of the H/D ratio in molecular hydrogen suggested that the step to form molecular hydrogen from surface hydrogen species was slow on the Ru catalyst, whereas the step to split the methine C-H bond was rather difficult for the Pt and Ru-Pt catalysts. Reflecting the facile dissociation at the hydroxy group on the catalyst surface, deuterium transfer from the hydroxy to the methyl groups of both acetone and 2-propanol proceeded tremendously for (CH3)2CHOD.
• Ando, Yuji,Yamashita, Masaru,Saito, Yasukazu

• p. 2045 - 2049

  (2003)
• Read Online

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• Japp,Streatfeild

• p. 270

  (1882)
• Read Online

• Products of the Gas-Phase OH Radical-Initiated Reactions of 4-Methyl-2-Pentanone and 2,6-Dimethyl-4-Heptanone
• The gas-phase reactions of OH radical with 4-methyl-2-pentanone and 2,6-dimethyl-4-heptanone have been investigated in the presence of NOx.Acetone and 2-methylpropanal were identified and quantified as products of both reactions.The acetone yield from 2,6-dimethyl-4-heptanone increased after addition of NO to reacted mixtures, indicating that acetone is formed through the intermediary of an acyl radical.The acetone and 2-methylpropanal formation yields were determined to be 0.78 +/- 0.06 and 0.071 +/- 0.011, respectively, from 4-methyl-2-pentanone and 0,68 +/- 0.11 and 0.385 +/- 0.034, respectively, from 2,6-dimethyl-4-heptanone.The possible reaction mechanisms are discussed and compared with these product data, and it is concluded that the experimental data provide direct evidence for isomerization of the (CH3)2CHCH2C(O)CH2C(O.)(CH3)2 alkoxy radical formed from 2,6-dimethyl-4-heptanone.However, the isomerization rates of the alkoxy radicals formed from the ketones depend on whether the H-atom abstracted is on a carbon atom α or β to the >C=O group, with H-atom abstraction from C-H bonds on the β carbon atoms being significantly faster than from C-H bonds on the α carbon atoms.
• Atkinson, Roger,Aschmann, Sara M.

• p. 261 - 276

  (1995)
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• Reactions Involving Electron Transfer at Semiconductor Surfaces. Part 12.- Nature and Origins of Photoactivity on Oxides of 3d Transition Metals for Elimination Reactions of Secondary Alcohols
• Activity for conversions of the vapours of propan-2-ol and butan-2-ol into products corresponding formally to elimination of H2,H2O or a (Cα-Cβ) bond from the parent alcohol were compared for oxides of the 3d transition metals under thermal- and photo-activation.Use of a gas-chromatographic, continuous reactant-flow technique with f.i.d. detection favoured the detection of products corresponding to a large turnover per surface site (t.a.p.s.).Under these conditions photoenhancement of the (-H2) and (Cα-Cβ) products at significant levels was detected only over ZnO and TiO2 and in the presence of gaseous oxygen.Such photocatalytic activity, and the contrasting absence of photoactivity continuing to high turnover over oxides featuring cations with partially filled 3d levels, is attributed to predominance and persistence of an O(1-)-type character and reactivity only for holes photogenerated in the diamagnetic ZnO and TiO2 samples.Photoassisted reaction of alcohol with several oxides at t.a.p.s. ca. 1, i.e. with the first monolayer of those oxides, could be observed using a more sensitive mass-spectrometric technique.This also revealed incorporation of oxygen-18 into acetone produced from propan-2-ol under these conditions, and the origins of this exchange at low t.a.p.s. are considered.Poisoning experiments employing a gas-chromatographic pulsed reactant technique at low t.a.p.s. provide evidence that photoassisted activity on ZnO involves photoinitiated one-electron transfer processes.
• Cunningham, Joseph,Hodnett, Benjamin K.,Ilyas, Mohammad,Leahy, Edward M.,Tobin, John P.

• p. 3297 - 3306

  (1982)
• Read Online

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• Williams et al.

• p. 1190

  (1956)
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• Uncatalyzed and amine catalyzed decarboxylation of acetoacetic acid: An examination in terms of No Barrier Theory
• Rate constants for decarboxylation of acetoacetic acid, its anion, and its imine with aminoacetonitrile have been calculated from equilibrium constants and distortion energies using No Barrier Theory. The mechanisms of decarboxylation of both acetoacetic acid and its imine involve preequilibrium formation of the zwitterion.
• Guthrie, J. Peter

• p. 32 - 52

  (2002)
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• Kinetics of one-stage Wacker-type oxidation of C2-C4 olefins catalysed by an aqueous PdCl2-heteropoly-anion system
• The steady-state kinetics of the one-stage Wacker oxidation of gaseous olefins, e.g., ethylene, propylene, and 1-butene by oxygen catalyzed by the Pd(II)/heteropoly anions-3 redox system to form, respectively, acetaldehyde, acetone, and methyl ethyl ketone in aqueous solution was studied. The catalytic system involved an aqueous solution of Pd(II) chloride (0.05-2 mM Pd(II), [Pd(II)]/[Cl-] = l: 50) and Keggin-type heteropoly anions [PMo9V3O40]6-(50 mM), at 20°-50°C. The reactivity of olefins increases in the following order: ethylene ≤ 1-butene propylene; but the total range was only a factor of 3. The oxidation of ethylene and propylene occurred without any complication. The oxidation of 1-butene was accompanied by double-bond migration to form 2-butene, apparently proceeding through relatively stable π-allyl Pd(II) complexes. Use of a flow reactor with continuous removal of the products from the catalyst solution could reduce their overoxidation.
• Kozhevnikov,Lambert,Derouane

• p. 445 - 450

  (2002)
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• The direct formation of ketones by reaction of methyl- and aryl-(carbonyl)(iodo)pentamethylcyclopentadienylrhodium complexes with organic iodides
• reacts with methyl iodide to give and arylCOMe; similar reactions occur between and RI to give the ketones RCOMe (R = Ph, Me, Et, or Pr).
• Fanizzi, Francesco P.,Sunley, Glenn J.,Maitlis, Peter M.

• p. C31 - C32

  (1987)
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• EFFECT OF PRESSURE ON THE DECOMPOSITION OF 2-TERT-BUTYL PEROXIDE IN SOLUTION
• A study was carried out on the effect of pressure up to 1400 MPa on the homolytic decomposition of di-tert-butyl peroxide (DTBP) at 403 K in 2-methoxy- (I) and 2-ethoxytetrahydropyran (II) as well as in a mixture of 30 mole percent (I) and 70 mole percent benzene.Spline approximation of the experimental pressure dependence of the logarithm of the decomposition rate constant (kd) gave the continuous dependence of the volumetric activation effect (ΔV excit.) on pressure.The value of ΔV excit. at atmospheric pressure (ΔV excit.0) and the nature of the change of ΔV excit. with increasing pressure were found to depend on the nature of the solvent.This dependence is difficult to explain in the framework of the accepted transition state theory.
• Zhulin, V. M.,Khueidzha, I.,Kabotyanskaya, E. B.,Koreshkov, Yu. D.

• p. 1739 - 1742

  (1990)
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• Physical and catalytic properties of MgO prepared using citric acid
• The physical properties, particularly the pore structure and specific surface area, of MgO prepared using citric acid was investigated. Both the specific surface area and the pore volume increased steeply with the weight loss at around 600 K at which citric acid was decomposed. The pore size distribution of the sample was controlled by the ratio of citric acid and the temperature of heat treatment. In a catalytic decomposition of 4-hydroxy-4-methyl-2-pentanone into acetone, the reaction rate was proportional to the specific surface area of the sample, and the catalysts prepared by this technique had high reaction rates because of their high specific surface areas.
• Nakayama, Tomohiro,Sato, Satoshi,Nozaki, Fumio

• p. 2107 - 2110

  (1996)
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• Propane selective oxidation on alkaline earth exchanged zeolite Y: Room temperature in situ IR study
• The effect of zeolite Y ion-exchanged with a series of alkaline-earth cations on selective propane oxidation at room temperature was studied with in situ IR spectroscopy. Isopropylhydroperoxide was a reaction intermediate and could be decomposed into acetone and water. BaY was active at room temperature. The reaction rate increased in the order BaY MgY SrY CaY based on the rate of formation of adsorbed acetone. The acetone/water ratio increased with cation size, while no other products could be detected. The acetone/isopropylhydroperoxide ratio decreased with decreasing number of Bronsted acid sites. A two-step mechanism with two different active sites was proposed. Propane conversion into isopropylhydroperoxide took place on cations, while acetone decomposition occurred by Bronsted acid sites.
• Xu, Jiang,Mojet, Barbara L.,Van Ommen, Jan G.,Lefferts, Leon

• p. 4407 - 4413

  (2003)
• Read Online

• Experimental and theoretical studies of the elimination kinetics of 3-hydroxy-3-methyl-2-butanone in the gas phase
• The kinetics of the gas-phase elimination of 3-hydroxy-3-methyl-2-butanone was investigated in a static system, seasoned with allyl bromide, and in the presence of the free chain radical inhibitor toluene. The working temperature and pressure range were 439.6-4-89.3°C and 81-201.5 Torr (1 Torr = 133.3 Pa), respectively. The reaction was found to be homogeneous, unimolecular and to follow a first-order rate law. The products of elimination are acetone and acetaldehyde. The temperature dependence of the rate coefficients is expressed by the following equation: log[k1(s-1)] = (13.05 ± 0.53) - (229.7 ±5.3) kJ mol-1 (2.303RT)-1. Theoretical estimations of the mechanism of this elimination suggest a molecular mechanism of a concerted non-synchronous four-membered cyclic transition-state process. An analysis of bond order and natural bond orbital charges suggests that the bond polarization of C(OH) - C(=O) -, in the sense of C(OH) δ+...C(=O)δ-, is rate limiting in the elimination reaction. The rate coefficients obtained experimentally are in reasonably good agreement with the theoretical calculations. The mechanism of 3-hydroxy-3-methyl-2-butanone elimination is described. Copyright
• Graterol, Mariana,Rotinov, Alexandra,Cordova, Tania,Chuchani, Gabriel

• p. 595 - 601

  (2005)
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• Electron-Transfer Conversion of Isopropylideneadamantane to its Dioxetane
• Adamantylideneadamantane (1) yields its dioxetane 2 by reaction with 3O2 and catalytic tris(o,p-dibromophenyl)aminium hexachloroantiminate (4) at -78 deg C in CH2Cl2 with a chain length of over 800.Isopropylideneadamantane (5) produces its dioxetane 6 under the same conditions with a chain length of greater than 60.
• Nelsen, Stephen F.,Kapp, Daniel L.,Teasley, Mark F.

• p. 579 - 580

  (1984)
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• Mechanism of the Wacker Oxidation of Alkenes over Cu-Pd-Exchanged Y Zeolites
• The catalytic potential of CuPd zeolites with faujasite topology in the Wacker oxidation of 1-alkenes with dioxygen is reported and compared with that of a homogeneous PdCl2-CuCl2 salt solution.The influence of water, oxygen, and alkene partial pressure on the rate of oxidation and the use of different alkenes and perdeuterated ethene as substrate allowed to establish similarities between the heterogeneous and homogenous system as well as specific zeolite effects.In situ IR and ESR spectroscopy of a working catalyst allowed to propose an active site consisting of a trinuclear Cu-O-Pd-O-Cu cationic complex and a catalytic cycle for the Wacker oxidation in which the reoxidation of Cu+ by dioxygen or of Pd0 by zeolite Cu2+ is rate determining.Diagnostic probing of the phenomena with CO in IR and ESR confirmed this picture.
• Espeel, P. H.,Peuter, G. De,Tielen, M. C.,Jacobs, P. A.

• p. 11588 - 11596

  (1994)
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• A common feature of H2-assisted HC-SCR over Ag/Al 2O3
• CH4, C2H2, C2H4, C3H6, and C3H8 were selected as reductants for selective catalytic reduction (SCR) of NOx over Ag/Al2O3. Activity measurement showed that NOx reduction by hydrocarbons containing two- or three-carbon atoms was clearly promoted by H2 over Ag/Al2O3 at low temperatures, while such enhancement did not occur in the case of CH 4-SCR. Gas chromatography and gas chromatography coupled to a mass spectrometer analysis showed that the partial oxidation of hydrocarbons with more than one carbon atom was triggered at low temperatures by H2 addition over Ag/Al2O3. On the surface of Ag/Al 2O3, in situ diffuse reflectance infrared Fourier transform spectra indicated that this enhancement mainly originated from the formation of reactive enolic species, which is a common feature of H 2-assisted HC-SCR. the Partner Organisations 2014.
• Yu, Yunbo,He, Hong,Zhang, Xiuli,Deng, Hua

• p. 1239 - 1245

  (2014)
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• Effect of Axial Azide on the Selective, Low Temperature Metalloporphyrin-catalysed Reactions of Isobutane with Molecular Oxygen
• Azido(tetraphenylporphyrinato) complexes of Cr(III), Mn(III), and Fe(III) catalyse selective, low temperature hydroxylation of isobutane with molecular oxygen and provide many turnovers in the absence of added co-reductants.
• Ellis, Paul E.,Lyons, James E.

• p. 1187 - 1188

  (1989)
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• Effect of Pressure on the Thermolysis of Nitroalkanes in Solution
• The effect of pressure up to 1.1 GPa on the rates of decomposition of two acidic nitroalkanes, nitromethane and 2-nitropropane, was measured. The mechanisms of thermolysis are inferred from kinetic studies and product analysis. The rate-controlling step for nitromethane decomposition in toluene at 230°C at low pressures is homolysis of the C-N bond. Beyond 20% conversion, the decomposition is autocatalytic. At high pressure, nitromethane has another reaction path which supplants homolysis. It is proposed that nitromethane forms an intermediate by cyclization of its aci-form. The high-pressure process is characterized by a first-order rate law without primary kinetic isotope effect, a low activation energy (28.5 kcal/mol), a negative activation volume (-5.5 mL/mol), and formation of products which cannot be attributed to radical intermediates. At high conversion, the reaction becomes autocatalytic as a result of accumulation of water leading to formation of products explainable by the Nef reaction. 2-Nitropropane is less stable than nitromethane. Pressure powerfully accelerates its decomposition owing to its activation volume averaging -11.2 mL/mol from 0.1 to 1.1 GPa. It is believed to cyclize via the aci-form like nitromethane. 2,2-Dinitropropane does not have a hydrogen and cannot tautomerize. In earlier work it was found to have a homolytic mechanism at high pressure. Therefore, the decomposition pathways of nitroalkanes in aprotic solvents are determined not only by the conditions but also by the availability of a hydrogen.
• Wang, Jiang,Brower, Kay R.,Naud, Darren L.

• p. 9048 - 9054

  (1997)
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• COMPARATIVE HAMETT STUDIES OF IMIDOYL, BENZYLIC, ALDEHYDIC HYDROGENS TRANSFER AND RELATED REACTION BY t-BUTOXYL RADICAL.
• The polar transition states involved in the hydrogen transfer reactions of N-benzylideneanilines, toluenes, benzaldehydes, and anisoles by t-butoxyl radical in benzene at 130 deg C have been comparatively discussed in terms of the values of the ? and the koa/kd.
• Kim, Sung Soo,Koo, Haeng Mo,Choi, Seung Yong

• p. 891 - 894

  (1985)
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• Products and mechanism of the reaction of OH radicals with 2,2,4-trimethylpentane in the presence of NO
• Alkanes are important constituents of gasoline fuel and vehicle exhaust, with branched alkanes comprising a significant fraction of the total alkanes observed in urban areas. The products and mechanism of the OH radical-initiated reaction products and mec
• Arey,Atkinson,Atkinson,Aschmann

• p. 625 - 632

  (2002)
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• Insights into the improvement effect of Fe doping into the CeO2 catalyst for vapor phase ketonization of carboxylic acids
• The conversion of carboxylic acid through ketonization process reduces O-atoms and increases C[sbnd]C bonds, which can provide attractive routes for upgrading biomass feedstocks into biofuels. The key factors influencing the surface ketonization activity over CeO2-based oxides catalysts remain matters of active discourse. Here, a series of Ce1-xFexO2-δ catalysts were investigated for vapor-phase ketonization of acetic and propionic acid. The catalysts were characterized in detail using various physico-chemical techniques both before and after reaction to gain understanding of the ketonization process. The turnover frequency (TOF) based on the basic sites changed with the Fe content. The Ce0.8Fe0.2O2-δ sample showed the prominent ketonization activity with the highest TOF value. On one hand, for samples with a lower Fe addition (x 2-like solid solution with numerous Ce-O-Fe species showed a dramatic increase in surface oxygen vacancies. These oxygen vacancies were beneficial to catalytic performance. Moreover, the superior redox properties with weaken M[sbnd]O bonds of Ce-O-Fe species thereby promote the ketonization activity. On the other hand, the higher Fe addition (x > 0.3) caused the damage of the Ce-O-Fe structure, thus reducing ketonization activity. Notably, the investigation of the reaction temperature regime of Ce0.8Fe0.2O2-δ sample directly proved the existence of surface redox cycle during the ketonization process.
• Lu, Feipeng,Jiang, BinBo,Wang, Jingdai,Huang, Zhengliang,Liao, Zuwei,Yang, Yongrong

• p. 22 - 33

  (2018)
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• Carbonylative Polymerization of Epoxides Mediated by Tri-metallic Complexes: A Dual Catalysis Strategy for Synthesis of Biodegradable Polyhydroxyalkanoates
• Polyhydroxyalkanoates (PHAs) are a unique class of commercially manufactured biodegradable polyesters with properties suitable for partially substituting petroleum-based plastics. However, high costs and low volumes of production have restricted their application as commodity materials. In this study, tri-metallic complexes were developed for carbonylative polymerization via a dual catalysis strategy, and 17 products of novel PHAs with up to 38.2 kg mol?1 Mn values were discovered. The polymerization proceeds in a sequential fashion, which entails the carbonylative ring expansion of epoxide to β-lactone and its subsequent ring-opening polymerization that occurs selectively at the O-alkyl bond via carboxylate species. The wide availability and structural diversity of epoxide monomers provide PHAs with various structures, excellent functionalities, and tunable properties. This study represents a rare example of the preparation of PHAs using epoxides and carbon monoxide as raw materials.
• Li, Wen-Bing,Liu, Ye,Lu, Xiao-Bing,Yang, Jin-Chuang,Yang, Jun
• supporting information

  (2022/01/20)
• 

• Ethanol Steam Reforming by Ni Catalysts for H2 Production: Evaluation of Gd Effect in CeO2 Support
• Abstract: Ni-based catalysts supported on CeO2 doped with Gd were prepared in this work to investigate the role of gadolinium on ethanol conversion, H2 selectivity, and carbon formation on ethanol steam reforming reaction. For this, catalysts containing 5 wt% of Ni impregnated on supports of ceria modified with different amounts of Gd (1, 5, and 10 wt%) were used. Ex-situ studies of XRPD suggest an increase of the lattice parameters, indicating a solid solution formation between Gd and Ce. Results of TPR showed an increase in metal-support interactions as the content of Gd increased. In situ XRPD studies indicated the formation of a GdNiO ternary phase for the catalysts containing Gd, which is in agreement with the results obtained by XANES. The catalysts were tested at three temperatures: 400?°C, 500?°C, and 600?°C. The conversion and productivity showed dependence with the Gd content and also with the temperature of the reaction. After the catalytic tests, catalysts containing Gd presented filamentous carbon possible due to a change in the reaction pathway. The highest ethanol conversion and H2 productivity were obtained at 600?°C for all catalysts and the best catalyst at this temperature was 5Ni_5GdCeO2. The promising performance of this catalyst may be associate with the lowest formation of GdNiO ternary phase, among the catalysts containing Gd, which means more Ni0 active species available to convert ethanol. Graphical Abstract: [Figure not available: see fulltext.]
• Assaf, Elisabete M.,Ferreira, Gabriella R.,Lucrédio, Alessandra F.,Nogueira, Francisco G. E.

• (2022/01/19)
• 

• Tris(pentafluorophenyl)borane-Catalyzed Formal Cyanoalkylation of Indoles with Cyanohydrins
• Despite the significant achievements related to the C3 functionalization of indoles, cyanoalkylation reactions continue to remain rather limited. We herein report on the formal C3 cyanoalkylation of indoles with cyanohydrins in the presence of a tris(pentafluorophenyl)borane (B(C6F5)3) catalyst. It is noteworthy that cyanohydrins are used as a cyanoalkylating reagent in the present reaction, even though they are usually used as only a HCN source. Mechanistic investigations revealed the unique reactivity of the B(C6F5)3 catalyst in promoting the decomposition of a cyanohydrin by a Lewis acidic activation through the coordination of the cyano group to the boron center. In addition, a catalytic three-component reaction using indoles, aldehydes as a carbon unit, and acetone cyanohydrin that avoids the discrete preparation of each aldehyde-derived cyanohydrin is also reported. The developed methods provide straightforward, highly efficient, and atom-economic access to various types of synthetically useful indole-3-acetonitrile derivatives containing α-tertiary or quaternary carbon centers.
• Kiyokawa, Kensuke,Minakata, Satoshi,Urashima, Naruyo

• p. 8389 - 8401

  (2021/06/28)
• 

• 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)
• 

• The mechanism of organic radical oxidation catalysed by gold nanoparticles
• Metal nanoparticles can catalyze reactions involving organic free radicals. From the first studies focused on the catalytic reduction of water by free radicals until today, the catalytic oxidation of organic radicals has not received attention. In this work, we present the results on the catalytic activity of gold nanoparticles in the oxidation of 2-propanol to acetone and acetanilide hydroxylation during water radiolysis. A detailed reaction mechanism of α-hydroxyisopropyl radical oxidation is discussed, explaining the increase in acetone formation by ca. 340% in the presence of gold nanoparticles. In the case of acetanilide hydroxylation in the presence of nanoparticles, a strong effect of oxygen in the reaction mechanism was observed: The increase in the oxygen concentration from 0 to 1.22 mM leads to a 40-fold decrease in hydroxylation product formation. This observation is unexpected since, in the absence of gold nanoparticles, oxygen stimulates hydroxylation reactions. We propose that in the presence of both oxygen and nanoparticles, oxygen attaches first to acetanilide OH-Adducts, and then nanoparticles catalyze the oxidation of peroxyl type radicals, which does not lead to the formation of hydroxylation products.
• Denisov, Sergey A.,Mostafavi, Mehran,Shcherbakov, Viacheslav

• p. 26494 - 26500

  (2021/12/13)
• 

• Hydroperoxide method for the synthesis of p-tert-butylphenol
• The results of studies related to the development of a highly selective three-stage method for the synthesis of p-tert-butylphenol along with acetone are presented. The alkylation of isopropylbenzene with tert-butyl alcohol in the presence of concentrated sulfuric acid makes it possible to obtain only the para-isomer of tert-butylcumene. For the liquid-phase aerobic oxidation of p-tert-butylcumene in the presence of the phthalimide catalysts, the hydrocarbon conversion reaches 45% with a selectivity of hydroperoxide formation of 90–95%. The process of acid decomposition of p-tert-butylcumene hydroperoxide to p-tert-butylphenol and acetone was studied. Conditions providing the production of p-tert-butylphenol in a yield of 90% were found.
• Frolov, A. S.,Korshunova, A. I.,Koshel’, G. N.,Kurganova, E. A.,Yarkina, E. M.

• p. 1951 - 1956

  (2021/11/05)
• 

• Selective Functionalization of Hydrocarbons Using a ppm Bioinspired Molecular Tweezer via Proton-Coupled Electron Transfer
• An expanded porphyrin-biscopper hexaphyrin was introduced as a bioinspired molecular tweezer to co-catalyze functionalization of C(sp3)-H bonds. Theoretical and experimental investigations suggested that the biscopper hexaphyrin served as a molecular tweezer to mimic the enzymatic orientation/proximity effect, efficiently activating the N-hydroxyphthalimide (NHPI) via light-free proton-coupled electron transfer (PCET), at an exceptionally low catalyst loading of 10 mol ppm. The resulting N-oxyl radical (PINO) was versatile for chemoselective C-H oxidation and amination of hydrocarbons.
• Chen, Hongyu,Wang, Lingling,Xu, Sheng,Liu, Xiaohui,He, Qian,Song, Lijuan,Ji, Hongbing

• p. 6810 - 6815

  (2021/06/28)
• 

• Liquid-Phase Cyclohexene Oxidation with O2 over Spray-Flame-Synthesized La1?xSrxCoO3 Perovskite Nanoparticles
• La1?xSrxCoO3 (x=0, 0.1, 0.2, 0.3, 0.4) nanoparticles were prepared by spray-flame synthesis and applied in the liquid-phase oxidation of cyclohexene with molecular O2 as oxidant under mild conditions. The catalysts were systematically characterized by state-of-the-art techniques. With increasing Sr content, the concentration of surface oxygen vacancy defects increases, which is beneficial for cyclohexene oxidation, but the surface concentration of less active Co2+ was also increased. However, Co2+ cations have a superior activity towards peroxide decomposition, which also plays an important role in cyclohexene oxidation. A Sr doping of 20 at. % was found to be the optimum in terms of activity and product selectivity. The catalyst also showed excellent reusability over three catalytic runs; this can be attributed to its highly stable particle size and morphology. Kinetic investigations revealed first-order reaction kinetics for temperatures between 60 and 100 °C and an apparent activation energy of 68 kJ mol?1 for cyclohexene oxidation. Moreover, the reaction was not affected by the applied O2 pressure in the range from 10 to 20 bar. In situ attenuated total reflection infrared spectroscopy was used to monitor the conversion of cyclohexene and the formation of reaction products including the key intermediate cyclohex-2-ene-1-hydroperoxide; spin trap electron paramagnetic resonance spectroscopy provided strong evidence for a radical reaction pathway by identifying the cyclohexenyl alkoxyl radical.
• Büker, Julia,Alkan, Baris,Chabbra, Sonia,Kochetov, Nikolai,Falk, Tobias,Schnegg, Alexander,Schulz, Christof,Wiggers, Hartmut,Muhler, Martin,Peng, Baoxiang
• supporting information

  p. 16912 - 16923

  (2021/10/19)
• 

• Synthesis, characterization and catalytic performance in enantioselective reactions by mesoporous silica materials functionalized with chiral thiourea-amine ligand
• Chiral heterogeneous catalysts have been synthesized by grafting of silyl derivatives of (1R, 2R)- or (1S, 2S)-1,2-diphenylethane-1,2-diamine on SBA-15 mesoporous support. The mesoporous material SBA-15 and so-prepared chiral heterogeneous catalysts were characterized by a combination of different techniques such as X-ray diffractometry (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) surface area. Results showed that (1R, 2R)- and (1S, 2S)-1,2-diphenylethane-1,2-diamine were successively immobilized on SBA-15 mesoporous support. Chiral heterogeneous catalysts and their homogenous counterparts were tested in enantioselective transfer hydrogenation of aromatic ketones and enantioselective Michael addition of acetylacetone to β-nitroolefin derivatives. The catalysts demonstrated notably high catalytic conversions (up to 99%) with moderate enantiomeric excess (up to 30% ee) for the heterogeneous enantioselective transfer hydrogenation. The catalytic performances for enantioselective Michael reaction showed excellent activities (up to 99%) with poor enantioselectivities. Particularly, the chiral heterogeneous catalysts could be readily recycled for Michael reaction and reused in three consecutive catalytic experiments with no loss of catalytic efficacies.
• G?k, Ya?ar,G?k, Halil Zeki

• p. 853 - 874

  (2020/11/10)
• 

• N-Heterocyclic Carbene Complexes of Nickel, Palladium, and Iridium Derived from Nitron: Synthesis, Structures, and Catalytic Properties
• The mesoionic compound (1,4-diphenyl-1,2,4-triazol-4-ium-3-yl)phenylazanide, commonly referred to as Nitron, has been employed as a "crypto-NHC"to afford 1,2,4-triazolylidene compounds of nickel, palladium, and iridium. Specifically, Nitron reacts with NiBr2, PdCl2, and [Ir(COD)Cl]2 to afford the N-heterocyclic carbene complexes (NitronNHC)2NiBr2, (NitronNHC)2PdCl2, and (NitronNHC)Ir(COD)Cl, respectively. The lattermost compound reacts with (i) CO to afford the dicarbonyl compound (NitronNHC)Ir(CO)2Cl and (ii) CO, in the presence of PPh3, to afford the monocarbonyl compound (NitronNHC)Ir(PPh3)(CO)Cl. Structural studies on (NitronNHC)Ir(COD)Cl and (NitronNHC)Ir(CO)2Cl indicate that NitronNHC has a stronger trans influence than does Cl; furthermore, IR spectroscopic studies on (NitronNHC)Ir(CO)2Cl indicate that NitronNHC is electronically similar to the structurally related Enders carbene but is less electron donating than imidazol-2-ylidenes with aryl substituents. Significantly, the NitronNHC ligand affords catalytic systems, as illustrated by the ability of (NitronNHC)Ir(CO)2Cl to effect (i) the dehydrogenation of formic acid, (ii) aldehyde hydrosilylation, (iii) dehydrocoupling of hydrosilanes and alcohols, and (iv) ketone reduction via transfer hydrogenation.
• Quinlivan, Patrick J.,Loo, Aaron,Shlian, Daniel G.,Martinez, Joan,Parkin, Gerard

• p. 166 - 183

  (2021/02/05)
• 

• Tailoring Lewis/Br?nsted acid properties of MOF nodesviahydrothermal and solvothermal synthesis: simple approach with exceptional catalytic implications
• The Lewis/Br?nsted catalytic properties of the Metal-Organic Framework (MOF) nodes can be tuned by simply controlling the solvent employed in the synthetic procedure. In this work, we demonstrate that Hf-MOF-808 can be prepared from a material with a higher amount of Br?nsted acid sites,viamodulated hydrothermal synthesis, to a material with a higher proportion of unsaturated Hf Lewis acid sites,viamodulated solvothermal synthesis. The Lewis/Br?nsted acid properties of the resultant metallic clusters have been studied by different characterization techniques, including XAS, FTIR and NMR spectroscopies, combined with a DFT study. The different nature of the Hf-MOF-808 materials allows their application as selective catalysts in different target reactions requiring Lewis, Br?nsted or Lewis-Br?nsted acid pairs.
• Bohigues, Benjamin,Boronat, Mercedes,Corma, Avelino,Lopes, Christian W.,Meira, Débora M.,Moliner, Manuel,Rojas-Buzo, Sergio

• p. 10106 - 10115

  (2021/08/04)
• 

• Process for the preparation of higher order alkanones, preferably 6 -undecanone and derivatives thereof
• The present invention relates to a method of producing higher alkanones, preferably 6 undecanone., from ethanol and/or acetate, the method comprising (a) contacting the ethanol and/or acetate with at least one microorganism capable of carrying out carbon chain elongation to produce hexanoic acid and/or an ester thereof from the ethanol and/or acetate; (b) extracting the hexanoic acid and/or ester thereof from (a) using at least one extractant in an aqueous medium, wherein the extractant comprises at least one alkyl-phosphine oxide and at least one alkane comprising at least 12 carbon atoms; or at least one trialkylamine and at least one alkane comprising at least 12 carbon atoms; and (c) contacting the extracted hexanoic acid and/or ester thereof from (b) with at least one ketonization catalyst and eventually a further alkanoic acid comprising 1 to 22 carbon atoms under suitable reaction conditions for chemical ketonization of hexanoic acid and eventually the further alkanoic acid to a higher alkanone, preferably 6-undecanone.
• -
• Paragraph 0176-0181

  (2021/08/05)
• 

• METHOD FOR PRODUCING HIGHER LINEAR FATTY ACIDS OR ESTERS
• The present invention relates to a method of producing linear fatty acids comprising 7 to 28 carbon atoms or esters thereof using a combined biotechnological and chemical method. In particular, the present invention relates to a method of producing dodecanoic acid (i.e. lauric acid), via higher alkanones, preferably 6-undecanone.
• -
• Page/Page column 33-33

  (2021/11/26)
• 

• Surfactant-Assisted Ozonolysis of Alkenes in Water: Mitigation of Frothing Using Coolade as a Low-Foaming Surfactant
• Aqueous-phase ozonolysis in the atmosphere is an important process during cloud and fog formation. Water in the atmosphere acts as both a reaction medium and a reductant during the ozonolysis. Inspired by the atmospheric aqueous-phase ozonolysis, we herein report the ozonolysis of alkenes in water assisted by surfactants. Several types of surfactants, including anionic, cationic, and nonionic surfactants, were investigated. Although most surfactants enhanced the solubility of alkenes in water, they also generated excessive foaming during the ozone bubbling, which led to the loss of products. Mitigation of the frothing was accomplished by using Coolade as a nonionic and low-foaming surfactant. Coolade-assisted ozonolysis of alkenes in water provided the desired carbonyl products in good yields and comparable to those achieved in organic solvents. During the ozonolysis reaction, water molecules trapped within the polyethylene glycol region of Coolade were proposed to intercept the Criegee intermediate to provide a hydroxy hydroperoxide intermediate. Decomposition of the hydroxy hydroperoxide led to formation of the carbonyl product without the need for a reductant typically required for the conventional ozonolysis using organic solvents. This study presents Coolade as an effective surfactant to improve the solubility of alkenes while mitigating frothing during the ozonolysis in water.
• Buntasana, Supanat,Hayashi, Jun,Klumphu, Piyatida,Padungros, Panuwat,Saetung, Prakorn,Vilaivan, Tirayut
• supporting information

  (2022/02/23)
• 

• Acid-sensitive PEGylated cabazitaxel prodrugs for antitumor therapy
• Although the antitumor drug cabazitaxel shows great therapeutic potential, its high toxicity and poor water solubility limit its utility. However, the use of stimuli-responsive prodrugs is a promising strategy for overcoming these limitations. Herein, we report the synthesis of two highly water soluble, acid-sensitive PEGylated acyclic-ketal-linked cabazitaxel prodrugs (PKCs) with improved antitumor efficacy. In an acidic tumor microenvironment, the PKCs hydrolyzed rapidly to release the native drug, whereas they were stable in the normal physiological environment. Compared with cabazitaxel injection, the PKCs had much higher maximum tolerated doses; and in an MDA-MB-231 subcutaneous xenograft nude mouse model, the PKCs showed better antitumor efficacy and safety than cabazitaxel injection. The prodrug strategy reported herein could be useful for the development of other water soluble, acid-sensitive prodrugs with improved efficacy.
• Liu, Tao,Zou, Hui,Mu, Jingqing,Yu, Na,Xu, Yang,Liu, Guohua,Liang, Xingjie,Guo, Shutao
• supporting information

  p. 1751 - 1754

  (2021/03/08)
• 

• Use of Isopropyl Alcohol as a Reductant for Catalytic Dehydoxylative Dimerization of Benzylic Alcohols Utilizing Ti?O Bond Photohomolysis
• Photohomolysis of Ti?O bonds is utilized in photocatalytic generation of titanium(III) species for dehydroxylative dimerization of benzylic alcohols under UV-light irradiation by using isopropyl alcohol (IPA) as a stoichiometric reductant. In this reaction, IPA works not as a single-electron donor as in the photo-redox catalyzed reactions but as an H-atom-donor. The reaction also proceeds under visible-light irradiation in the presence of thioglycolic acid as a ligand.
• Iwasawa, Nobuharu,Sumiyama, Keiichi,Toriumi, Naoyuki
• supporting information

  p. 2474 - 2478

  (2021/06/25)
• 

• Kinetic and Structural Analysis of Two Linkers in the Tautomerase Superfamily: Analysis and Implications
• The tautomerase superfamily (TSF) is a collection of enzymes and proteins that share a simple β-α-β structural scaffold. Most members are constructed from a single-core β-α-β motif or two consecutively fused β-α-β motifs in which the N-terminal proline (Pro-1) plays a key and unusual role as a catalytic residue. The cumulative evidence suggests that a gene fusion event took place in the evolution of the TSF followed by duplication (of the newly fused gene) to result in the diversification of activity that is seen today. Analysis of the sequence similarity network (SSN) for the TSF identified several linking proteins ("linkers") whose similarity links subgroups of these contemporary proteins that might hold clues about structure-function relationship changes accompanying the emergence of new activities. A previously uncharacterized pair of linkers (designated N1 and N2) was identified in the SSN that connected the 4-oxalocrotonate tautomerase (4-OT) and cis-3-chloroacrylic acid dehalogenase (cis-CaaD) subgroups. N1, in the cis-CaaD subgroup, has the full complement of active site residues for cis-CaaD activity, whereas N2, in the 4-OT subgroup, lacks a key arginine (Arg-39) for canonical 4-OT activity. Kinetic characterization and nuclear magnetic resonance analysis show that N1 has activities observed for other characterized members of the cis-CaaD subgroup with varying degrees of efficiencies. N2 is a modest 4-OT but shows enhanced hydratase activity using allene and acetylene compounds, which might be due to the presence of Arg-8 along with Arg-11. Crystallographic analysis provides a structural context for these observations.
• Baas, Bert-Jan,Babbitt, Patricia C.,De Ruijter, Marieke,Erwin, Kaci,Johnson, William H.,Kaoud, Tamer S.,Lancaster, Emily B.,Levieux, Jake A.,Medellin, Brenda P.,Moreno, R. Yvette,Whitman, Christian P.,Zhang, Yan Jessie

• p. 1776 - 1786

  (2021/06/21)
• 

• Linkage engineering mediated carriers transfer and surface reaction over carbon nitride for enhanced photocatalytic activity
• Rational tailoring of the atomic structure of photocatalysts with multiple functions to enhance the carrier transfer efficiency and surface activation of carbon nitride (C3N4) is promising and a challenge. Here, we make the first report of a facile strategy to construct amphiphilic carbon and C-O-C chain linked terminal melem units in functional carbon nitride (COCN)viacopolymerizing formaldehyde with melem. By integrating the amphiphilic carrier bridge of carbon and C-O-C chains into the framework, the photogenerated carrier mobility and activated species (superoxide radicals, singlet oxygen) as well as surface interaction are significantly improved. Consequently, the optimal tailoring of C3N4attains superior photocatalytic activity for hydrogen production (34.9 μmol h?1) and selective oxidation of sulfide to sulfoxide using air (nearly 100% conversion and selectivity after 3 h of illumination), which is about 7 times higher than that of pristine C3N4. This study provides deep insight into and strategies for the atomic tailoring of carrier transfer and surface reaction over organic-based photocatalysts.
• Chen, Peng,Li, Gen,Liu, Fei,Wang, Qian,Wang, Qiuchen,Yang, Shilian,Yin, Shuang-Feng,Zhao, Tianxiang

• p. 21732 - 21740

  (2021/10/14)
• 

• Enhanced CO2 Conversion into Ethanol by Permanently Polarized Hydroxyapatite through C?C Coupling
• Hydroxyapatite (HAp) is a naturally occurring mineral form of calcium apatite of biomedical importance due to its similarity with human hard tissues in morphology and composition. Upon polarization at high temperature, applying 3 kV/cm at 1000 °C, the resulting polarized HAp (p-HAp) exhibits enhanced catalytic behavior due charge accumulation at the interface. More specifically, p-HAp was found to catalyse the conversion of mixtures of CO2(g) and CH4(g) into low carbon organic molecules and into amino acids when N2(g) was added to the mixture. In this work, we report how p-HAp facilitates the conversion of CO2(g) mainly in ethanol by means of forming C?C coupled bonds on its activated surface. After evaluation of a wide range of experimental conditions, we evidence the production of formic acid, methanol and formaldehyde (C1 products); ethanol and acetic acid (C2 products); and acetone (C3 product) from CO2(g) using moderate reaction conditions. Moreover, optimization of the reaction parameters led to a significant increase towards ethanol.
• Sans, Jordi,Sanz, Vanesa,Turon, Pau,Alemán, Carlos

• p. 5025 - 5033

  (2021/10/29)
• 

• Low temperature steam reforming of ethanol over cobalt doped bismuth vanadate [Bi4(V0.90Co0.10)2O11-δ (BICOVOX)] catalysts for hydrogen production
• The atmospheric pressure low temperature steam reforming of ethanol over Bi4(V0.90Co0.10)2O11-δ (BICOVOX) catalysts, synthesize by a solution combustion synthesis method and calcined at 400, 600 and 800 °C, has been investigated at different reactor temperatures, H2O: EtOH molar ratios and feed flow rates. For fresh catalysts amount, crystallinity and particle size of pure γ-BICOVOX phase is observed to increase with increasing calcination temperature. Phase purity and crystallinity of the catalysts are almost retained till 30 h of activity study with some amount of carbon formation as derived from XRD, XPS, FESEM and simultaneous DTA-TGA study. Catalyst calcined at 600 °C (BICOVOX-600) exhibits the highest ethanol conversion (100%) with maximum H2 selectivity (80%) under reaction conditions of 400 °C, 23:1H2O: EtOH molar ratio and 0.35 cc min?1 feed flow rate. The maximum O2? vacancy present in lattice and lowest coke deposition could explain the best performance of BICOVOX-600 catalyst.
• Aich, Shampa,Roy, Banasri,Sharma, Shweta

• (2020/10/02)
• 

• Mechanistic Insights into Fe Catalyzed α-C?H Oxidations of Tertiary Amines
• We report detailed mechanistic investigations of an iron-based catalyst system, which allows the α-C?H oxidation of a wide variety of amines. In contrast to other catalysts that effect α-C?H oxidations of tertiary amines, the system under investigation exclusively employs peroxy esters as oxidants. More common oxidants (e. g. tBuOOH) previously reported to affect amine oxidations via free radical pathways do not provide amine α-C?H oxidation products in combination with the described catalyst system. The investigations described herein employ initial rate kinetics, kinetic profiling, DFT calculations as well as Eyring, kinetic isotope effect, Hammett, ligand coordination, and EPR studies to shed light on the Fe catalyst system. The obtained data suggest that the catalytic mechanism proceeds through C?H abstraction at a coordinated substrate molecule. This rate-determining step occurs either through an Fe(IV) oxo pathway or a 2-electron pathway at an Fe(II) intermediate with bound oxidant. DFT calculations indicate that the Fe(IV) oxo mechanism will be the preferred route of these two possibilities. We further show via kinetic profiling and EPR studies that catalyst activation follows a radical pathway, which is initiated by hydrolysis of PhCO3tBu to tBuOOH. Overall, the obtained mechanistic data support a non-classical, Fe catalyzed pathway that requires substrate binding, inducing selectivity for α-C?H functionalization.
• Legacy, Christopher J.,Hope, Taylor O.,Gagné, Yohann,Greenaway, Frederick T.,Frenette, Mathieu,Emmert, Marion H.

• p. 235 - 246

  (2020/10/19)
• 

• Operando Investigation of Ag-Decorated Cu2O Nanocube Catalysts with Enhanced CO2 Electroreduction toward Liquid Products
• Direct conversion of carbon dioxide into multicarbon liquid fuels by the CO2 electrochemical reduction reaction (CO2RR) can contribute to the decarbonization of the global economy. Here, well-defined Cu2O nanocubes (NCs, 35 nm) uniformly covered with Ag nanoparticles (5 nm) were synthesized. When compared to bare Cu2O NCs, the catalyst with 5 at % Ag on Cu2O NCs displayed a two-fold increase in the Faradaic efficiency for C2+ liquid products (30 % at ?1.0 VRHE), including ethanol, 1-propanol, and acetaldehyde, while formate and hydrogen were suppressed. Operando X-ray absorption spectroscopy revealed the partial reduction of Cu2O during CO2RR, accompanied by a reaction-driven redispersion of Ag on the CuOx NCs. Data from operando surface-enhanced Raman spectroscopy further uncovered significant variations in the CO binding to Cu, which were assigned to Ag?Cu sites formed during CO2RR that appear crucial for the C?C coupling and the enhanced yield of liquid products.
• Herzog, Antonia,Bergmann, Arno,Jeon, Hyo Sang,Timoshenko, Janis,Kühl, Stefanie,Rettenmaier, Clara,Lopez Luna, Mauricio,Haase, Felix T.,Roldan Cuenya, Beatriz
• supporting information

  p. 7426 - 7435

  (2021/02/26)
• 

• Ketoreductase/Transaminase, One-Pot, Multikilogram Biocatalytic Cascade Reaction
• A biocatalytic cascade to produce tert-butyl ((2R,4R)-2-methyltetrahydro-2H-pyran-4-yl)carbamate 6 has been demonstrated at the multikilogram scale. In this reaction, a racemic ketone is resolved by reducing the undesired ketone using a ketone reductase (KRED). The reduction is stereospecific for the 2-position of substrate (2S)-ketone leaving the (2R)-ketone unreacted. After the (2S)-ketone has been depleted, a transaminase is added to catalyze the enantioselective transamination of the ketone, resulting in formation of the (2R, 4R)-amine 6. The product is recovered from the aqueous reaction after Boc protection.
• Burns, Michael,Bi, Wenying,Kim, Hui,Lall, Manjinder S.,Li, Chao,O'Neill, Brian T.

• p. 941 - 946

  (2021/03/01)
• 

• Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
• Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
• Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín

• p. 2084 - 2092

  (2021/04/02)
• 

• 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)
• 

• Copper-Containing Catalysts Based on Cerium–Zirconium Oxide Supports in Ethanol Conversion Reaction According to In Situ IR Spectroscopic Data
• Abstract: Copper-containing catalysts based on CeO2–ZrO2 solid solutions were prepared by the Pecini method and studied using a set of physicochemical methods. It was found that the bond strength of oxygen on the catalyst surface, which depends on the properties of supported copper oxide clusters and a ratio between CeO2 and ZrO2 in the support, plays a main role in ethanol conversion. Ethoxy groups, acetate and formate complexes, and condensation products were detected as main surface intermediates formed in the course of ethanol conversion on the catalysts. The decomposition of the formate complexes was the key stage in the formation of hydrogen. Its appearance on the surface of the catalysts was due to the competition between the reactions of formate and acetate complex formation for oxygen with suitable properties.
• Ilichev, A. N.,Korchak, V. N.,Matyshak, V. A.,Sil’chenkova, O. N.

• p. 404 - 417

  (2021/06/14)
• 

• Facile Preparation of Methyl Phenols from Ethanol over Lamellar Ce(OH)SO4· xH2O
• Ethanol transformation with high product selectivity is a great challenge, especially for high weight molecules. Here, we show a combination study of kinetic, thermodynamic, and in situ spectroscopy measurements to probe the selective upgrading of ethanol over lamellar Ce(OH)SO4·xH2O catalysts, with 60-70% Ce3+ preserved during the catalysis. High methyl phenols (MPs) selectivity at ～80% within condensation products was achieved at ～50% condensation yield (3.0 kPa C2H5OH, 15 kPa H2, Ar balanced, 693 K, 1 atm, gas hourly space velocity (GHSV) ～5.4 min-1), with acetaldehyde, acetone, 4-heptanone, and 2-pentanone as the key reaction intermediates. Kinetic measurements with the assistance of isotope labeling proved that MPs generated from the kinetically relevant step (KRS) of C-C bond coupling of enolate nucleophilically attacks surface C2H4O following a Langmuir-Hinshelwood model. Low ethanol and water pressures and high acetaldehyde and hydrogen pressures were proved to be favored for MPs generation rather than dehydration, in which hydrogen could reduce the amount of lattice oxygen and facilitate the preparation of MPs while water and ethanol both compete with acetaldehyde for active sites during catalysis. On the basis of in situ X-ray diffraction (XRD), quasi-in situ X-ray photoelectron spectroscopy (XPS), and Raman characterizations, the Ce(OH)SO4 crystal structure was proved to be maintained along with ethanol activation, and the Ce3+-OH Lewis acid-base pair was proved to be the active species for the selective C-C bond coupling. The KRS assumption was also supported by the apparent activation energy assessment within the reaction network on dehydration, dehydrogenation, aldol condensation, and cyclization and a series of negligible kinetic isotope effects (KIEs). This system can be easily extended to some other systems related to C-C bond coupling and is attracting attention on converting oxygenate platform molecules over lanthanide species.
• Guo, Jinqiu,Feng, Zongjing,Xu, Jun,Zhu, Jie,Zhang, Guanghui,Du, Yaping,Zhang, Hongbo,Yan, Chunhua

• p. 6162 - 6174

  (2021/05/29)
• 

• Oxidation of Propane: Influence of the Nature of Catalyst, Cocatalyst, and Coreductant
• Abstract: Variation of the nature of the components of the catalytic systems comprisinga catalyst [Pd/C, Pd(α,α-bipy)Cl2,RhCl3] and a cocatalyst(FeSO4, CuSO4), as well as acoreductant (H2, CO), allows exerting some control overthe selectivity of the process of propane oxidation with oxygen. In particular,the yield of carbonyl compounds such as acetone and propanal in the presence ofthe Pd/C–FeSO4–H2catalytic systemreached 90%, and that of propyl esters in the presence ofRhCl3–CuSO4–CO catalyticsystem was 64.5%. These differences are supposedly attributable to the changesin the process mechanism depending on the composition of the catalyticsystems. [Figure not available: see fulltext.]
• Chepaikin, E. G.,Menchikova, G. N.,Pomogailo, S. I.

• p. 781 - 786

  (2021/08/03)
• 

• 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)
• 

• Synthesis of Pentacoordinated Spiro[44]phosphoranes by Reaction of Cyclic Phosphazenyl Anions with Epoxides: Study of their P-Remote Functionalization and Hydrolysis
• The synthesis of a new family of pentacoordinated spiro[4.4]phosphoranes stabilized by the ortho-benzamide bidentate ligand (oBA, -C6H4-2-C(O)NH-) through reaction of C,Cortho-dilithiated phosphazenes with oxiranes is reported. Mixtures of epimers that differ in configuration at the phosphorus atom were obtained with moderate to high yields and diastereoselectivities. C3-Disubstituted derivatives could be separated, which provided access to enantiopure products arising from the reaction with (R)-2-phenyloxirane. Stereomutation was observed by heating the spirophosphoranes at 100 C. Directed ortholithiation of spirophoshoranes followed by electrophilic quench reactions including carbon-based and heteroatom-based electrophiles afforded derivatives functionalized in a remote position with respect to the phosphorus atom. Benzoic acid catalyzed hydrolysis of spirophosphoranes furnished ortho-(γ-hydroxyalkylphosphoryl)benzamides by cleavage of the P O and P N bonds with retention of the phosphorus configuration. In contrast, alkaline hydrolysis led to the formation of γ- hydroxyphosphinic acids and benzamide.
• Sansores Peraza, Pablo M.,García López, Jesús,Navarro, Yolanda,Iglesias, María J.,López Ortiz, Fernando

• p. 600 - 616

  (2021/11/16)
• 

• Iridium Azocarboxamide Complexes: Variable Coordination Modes, C-H Activation, Transfer Hydrogenation Catalysis, and Mechanistic Insights
• Azocarboxamides, a special class of azo ligands, display intriguing electronic properties due to their versatile binding modes and coordination flexibility. These properties may have significant implications for their use in homogeneous catalysis. In the present report, half-sandwich Ir-Cp? complexes of two different azocarboxamide ligands are presented. Different coordination motifs of the ligand were realized using base and chloride abstracting ligand to give N∧N-, N∧O-, and N∧C-chelated monomeric iridium complexes. For the azocarboxamide ligand having methoxy substituted at the phenyl ring, a mixture of N∧C-chelated mononuclear (Ir-5) and N∧N,N∧C-chelated dinuclear complexes (Ir-4) were obtained by activating the C-H bond of the aryl ring. No such C-H activation was observed for the ligand without the methoxy substituent. The molecular identity of the complexes was confirmed by spectroscopic analyses, while X-ray diffraction analyses further confirmed three-legged piano-stool structure of the complexes along with the above binding modes. All complexes were found to exhibit remarkable activity as precatalysts for the transfer hydrogenation of carbonyl groups in the presence of a base, even at low catalyst loading. Optimization of reaction conditions divulged superior catalytic activity of Ir-3 and Ir-4 complexes in transfer hydrogenation over the other catalysts. Investigation of the influence of binding modes on the catalytic activity along with wide range substrates, tolerance to functional groups, and mechanistic insights into the reaction pathway are also presented. These are the first examples of C-H activation in azocarboxamide ligands.
• Albold, Uta,Chandra, Shubhadeep,Hazari, Arijit Singha,Kelm, Ola,Ko?mrlj, Janez,Sarkar, Biprajit,Urankar, Damijana
• supporting information

  p. 3907 - 3916

  (2021/12/03)
• 

• Transaminase Engineering and Process Development for a Whole-Cell Neat Organic Process to Produce (R)-α-Phenylethylamine
• The production of (R)-α-phenylethylamine ((R)-α-PEA) from acetophenone is a classic reaction for the characterization of transaminases. However, developing a commercially viable transaminase process to manufacture (R)-α-PEA usually suffers from two drawbacks. One is related to the biocatalyst itself, since transaminases are easily inhibited by (R)-α-PEA at low concentrations. The other drawback is a common low space-time yield of typical transaminase processes, because the reaction equilibrium greatly favors the formation of acetophenone(R)-α-PEA. In this study, an (R)-selective amine transaminase (TA) from Aspergillus fumigatus Af293 was engineered by a directed evolution for an efficient process to produce (R)-α-PEA. The evolved variant showed an3000-fold increase in activity and a tolerance with 2.0 M isopropylamine as well as the complete absence of inhibition by (R)-α-PEA. At the same time, using this evolved TA variant, a continuous neat organic process using whole-cells was developed where the biocatalyst and remaining acetophenone can be efficiently separated from (R)-α-PEA and reused repetitively. This not only decreases the overall cost and waste generation but also achieves a very high space-time yield of up to 168 g L-1 d-1 of (R)-α-PEA in an industrial pilot scale setup.
• Bocola, Marco,Bong, Yong Koy,Cai, Baoqin,Chen, Haibin,Daussmann, Thomas,He, Kuifang,Hong, Ruimei,Hu, Hu,Ji, Yaoyao,Liu, Sitong,Luo, Xiao,Peng, Qinli,Shang, Chuanyang,Sun, Lei,Wang, Jiyong,Wang, Juanjuan,Wang, Zikun,Yang, Zhuhong,Zhang, Chengxiao,Zhou, Ameng,Zhu, Ying

• (2022/01/04)
• 

• METHOD FOR PRODUCING OXIDATION REACTION PRODUCT OF HYDROCARBON OR DERIVATIVE THEREOF
• The present invention is intended to provide a method that can produce an oxidation reaction product of a hydrocarbon or a derivative thereof in an aqueous phase using a hydrocarbon or a derivative thereof as a raw material. In order to achieve the above object, the method for producing an oxidation reaction product of a hydrocarbon or a derivative thereof of the present invention includes the step of: irradiating a reaction system with light in a presence of a raw material and a halogen oxide radical to react, wherein the raw material is a hydrocarbon or a derivative thereof, the reaction system is a reaction system containing an aqueous phase, the aqueous phase contains the raw material and the halogen oxide radical, and in the reaction step, the raw material is oxidized to produce an oxidation reaction product of the raw material.
• -
• Paragraph 0099; 0103

  (2022/01/04)
• 

• 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.
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• Paragraph 0074

  (2022/01/04)
• 

• Metal-free Photocatalytic Aerobic Oxidative Cleavage of C?C Bonds in 1,2-Diols
• The preparation of carbonyl compounds by the aerobic oxidative cleavage of C?C bonds in 1,2-diols under mild reaction conditions is a very significant reaction and is widely employed in various scenarios. Avoiding the use of harmful stoichiometric oxidants and adopting a greener chemical process remain a challenge for this reaction to date. In this manuscript, a heterogeneous metal-free photocatalytic strategy without any additive was developed for aerobic oxidative cleavage of C?C bonds in 1,2-diols at ambient conditions with visible light. The reaction mechanism was further studied through a series of control experiments and density functional theory (DFT) calculations. In addition, the catalytic system showed a broad substrates scope, including aliphatic (linear or cyclic) 1,2-diols, benzylic, alkenyl 1,2-diols, and α-hydroxy acids (such as lactic acid). Thus, this strategy could serve as a method for the transformation of 1,2-diols to corresponding carbonyl compounds by the aerobic oxidative cleavage of C?C bonds.
• Zhu, Rui,Zhou, Gongyu,Teng, Jia-nan,Li, Xinglong,Fu, Yao

• p. 5248 - 5255

  (2020/08/21)
• 

• Formation of benzodiazepines and pyrazinylquinoxalines from aromatic and heteroaromatic ketones via deoximation
• The report stated that the treatment of o-phenylenediamine with acetone dicarboxylic acid, acetone and acetophenone afforded 2,4,4- trimethyl-3H-5-hydro-1,5-benzodiazepine. However, direct reactions of o-phenylenediamine with oximes (acetone oxime, acetophenone oxime, and benzophenone oxime) as ketone equivalents did not occur. In the course of present investigations, it is found that dichloroamineT can be an efficient reagent for the conversion of oximes into the corresponding carbonyl compounds. As a part of a research program related to the synthetic study of pharmacologically interesting benzodiazepine compounds, herein the synthesis of 1H-1,5-benzodiazepine derivatives from heteroaromatic ketones and acetone equivalents obtained using dichloroamine-T. On the other hand, when diamine (1,2- phenylene diamine or 1,2-naphthalene diamine) with heterocyclic ketone (acetyl pyridine or acetyl pyrazines) in the presenece of conc. HCl and SiO2was refluxed, quinoxaline derivatives as yellow crystalline solids were isolated in high yields.
• Song,Bae,Lee,Cho,Jung

• p. 1676 - 1680

  (2020/07/30)
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• Lewis Acid and Base Catalysis of YNbO4 Toward Aqueous-Phase Conversion of Hexose and Triose Sugars to Lactic Acid in Water
• Amphoteric YNbO4 was synthesized by the simple coprecipitation using (NH4)3[Nb(O2)4] and Y(NO3)3, and examined as a new solid acid-base bifunctional catalyst for various reactions including aqueous-phase conversion of glucose to lactic acid. After drying the white precipitate at 353 K for 3 h, the resultant oxide is an amorphous YNbO4 with high densities of Lewis acid sites (0.18 mmol g?1) and base sites (0.38 mmol g?1). Negatively-charged lattice oxygen of amorphous YNbO4 functioned as Lewis base sites that promote a Claisen-Schmidt-type condensation reaction with acetylacetone and benzaldehyde with comparable activity to reference catalysts. Amorphous YNbO4 can also be applicable to the production of lactic acid from glucose in water, which gives relatively high yields (19.6 %) compared with other reference catalysts. Mechanistic studies using glucose-1-d and 2H nuclear magnetic resonance spectroscopy (NMR) revealed that YNbO4 first converts glucose to two carbohydrates (glyceraldehyde and pyruvaldehyde) through dehydration via the formation of 3-deoxyglucosone and subsequent retro-aldolization, and these intermediates are then converted to lactic acid by both dehydration and isomerization through hydride transfer.
• Kim, Minjune,Ronchetti, Silvia,Onida, Barbara,Ichikuni, Nobuyuki,Fukuoka, Atsushi,Kato, Hideki,Nakajima, Kiyotaka

• p. 350 - 359

  (2019/11/14)
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• Comparison of the base catalytic activity of MgO prepared by thermal decomposition of hydroxide, basic carbonate, and oxalate under atmospheric conditions
• To obtain highly active solid base catalyst of magnesium oxide (MgO) under atmospheric conditions, hydroxide (Mg(OH)2), basic carbonate (Mg5(CO3)4(OH)2·4H2O), and oxalate (MgC2O4·2H2O) were examined as starting material for preparation, and the effect of heating temperature on base catalytic activity was studied. Diacetone alcohol decomposition, a retro-aldol reaction, was performed to compare the base catalytic activity of prepared MgO catalysts. The order of activity of MgO as starting material for the retro-aldol reaction was oxalate > basic carbonate > hydroxide. In a comparison of catalytic activity based on catalyst weight and surface area, MgO prepared from oxalate showed higher activity than did samples prepared from carbonate and hydroxide. Catalytic activity based on surface area was the highest in MgO prepared by thermal decomposition of oxalate at 1173?K. The starting material, which had higher decomposition temperature and formed a larger amount of evolving gas molecules accompanying decomposition, provided a solid base with higher activity under atmospheric conditions.
• Kitagawa, Michiko,Ishida, Nana,Yoshino, Erika,Matsuhashi, Hiromi

• p. 3703 - 3715

  (2020/05/11)
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• Transfer hydrogenation via generation of hydride intermediate and base-free alcohol oxidation activity studies on designed ruthenium complexes derived from NNN pincer type ligands
• Ruthenium complexes(1–3) have been synthesized using pincer-type ligands L1 = (E)-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)pyridine, L2 = (E)-2-(1-phenyl-2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)pyridine, L3 = (E)-2-(phenyl(2-phenyl-2-(pyridin-2-yl)hydrazono) methyl)pyridine. The molecular structures of all the complexes 1, 2 and 3 were determined by using single crystal X-ray diffraction. These complexes showed excellent catalytic activities such as transfer hydrogenation and alcohol oxidation. Theoretical calculations have been performed to understand the electronic properties of all the complexes using B3LYP as a function and LANL2DZ as a basis set.
• Singh, Prasoon Raj,Maji, Ankur,Singh, Ovender,Singh, Udai P.,Ghosh, Kaushik

• (2020/03/27)
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• Hydrothermal synthesis of boron-free Zr-MWW and Sn-MWW zeolites as robust Lewis acid catalysts
• An innovative strategy based on dual structure-directing agent-facilitated crystallization was proposed to hydrothermally synthesize boron-free Zr-MWW and Sn-MWW metallosilicates that bear great structural diversity for potential pore engineering. The metallosilicates show distinctive features in Lewis acid-catalyzed reactions as efficient heterogeneous solid catalysts.
• Guan, Yejun,Jiang, Jin-Gang,Lü, Hongying,Ma, Haikuo,Wu, Peng,Xu, Hao,Zhu, Zhiguo
• supporting information

  p. 4696 - 4699

  (2020/05/22)
• 

• gem-Diol-Type Intermediate in the Activation of a Ketone on Sn-β Zeolite as Studied by Solid-State NMR Spectroscopy
• Lewis acid zeolites have found increasing application in the field of biomass conversion, in which the selective transformation of carbonyl-containing molecules is of particular importance due to their relevance in organic synthesis. Mechanistic insight into the activation of carbonyl groups on Lewis acid sites is challenging and critical for the understanding of the catalytic process, which requires the identification of reaction intermediates. Here we report the observation of a stable surface gem-diol-type species in the activation of acetone on Sn-β zeolite. 13C, 119Sn, and 13C–119Sn double-resonance NMR spectroscopic studies demonstrate that only the open Sn site ((SiO)3Sn-OH) on Sn-β is responsible for the formation of the surface species. 13C MAS NMR experiments together with density functional theory calculations suggest that the gem-diol-type species exhibits high reactivity and can serve as an active intermediate in the Meerwein—Ponndorf–Verley–Oppenauer (MPVO) reaction of acetone with cyclohexanol. The gem-diol-type species offers an energy-preferable pathway for the direct carbon-to-carbon hydrogen transfer between ketone and alcohol. The results provide new insights into the transformation of carbonyl-containing molecules catalyzed by Lewis acid zeolites.
• Chu, Yueying,Deng, Feng,Lafon, Olivier,Li, Yi,Qi, Guodong,Trébosc, Julien,Wang, Qiang,Wang, Xingxing,Xu, Jun
• supporting information

  p. 19532 - 19538

  (2020/07/04)
• 

• Development of Plasmonic Photocatalyst by Site-selective Loading of Bimetallic Nanoparticles of Au and Ag on Titanium(IV) Oxide
• Morphology-controlled rutile titanium(IV) oxide (TiO2) and anatase TiO2 were prepared by a hydrothermal method and their surfaces were selectively loaded with Au, Ag and AuAg bimetallic nanoparticles (NPs) by photo-deposition in order to obtain visible-light responsive photocatalysts. With the help of local surface plasmon resonance (LSPR) of noble metal NPs, the photocatalytic activity of noble metal-loaded TiO2 under visible-light irradiation was improved compared to that of bare TiO2. The enhancement of LSPR on the photocatalytic activity of rutile TiO2 was larger than that of anatase TiO2 with optimum amount of Au or AuAg. In addition, the reusability (stability) of AuAg-loaded TiO2 was much better than that of Ag-loaded TiO2. Double-beam photoacoustic results confirmed different trap energy level distribution lead to different electron transfer ways, resulting in different oxidizing capabilities and they gave one of important strategies for designing visible-light responsive TiO2.
• Zheng, Zhi,Murakami, Naoya,Liu, Jingjing,Teng, Zhenyuan,Zhang, Qitao,Cao, Yu,Cheng, Honghui,Ohno, Teruhisa

• p. 3783 - 3792

  (2020/06/08)
• 

• Total Oxidation of Isopropanol in the Liquid Phase, under Atmospheric Pressure and Low Temperature, on Transition Metal Oxides Catalysts Cr2O3and Fe2O3
• Isopropanol oxidation in the liquid phase under atmospheric pressure and low temperature has been studied in the presence of transition metal oxides (Cr2O3 and Fe2O3) prepared by the precipitation method. These solids characterized by structural analyses (FTIR and XRD) and textural analysis (BET) have led to results in line with those reported in the literature. Chromium oxide has a much more developed texture, with a specific surface area and pore volume 5 times larger than iron oxide. Both of the solids show a good specific activity and led to acetone and carbon dioxide to be formed as the only oxidation products of isopropanol. However, chromium oxide is more active. The initial catalytic activity for the latter is varying between 4.87 ? 10-6 and 5.79 ? 10-6mol·g-1·s-1 with temperature range from 40 to 80°C. Kinetic study shows that the reaction follows a successive scheme: isopropanol → acetone → CO2 involving a redox mechanism. The low value of the activation apparent energy (Ea.(Cr2O3) = 2.87 kJ·mol-1 Ea. (Fe2O3) = 5.37 kJ·mol-1) justifies the relatively higher activity observed for chromium oxide.
• Abouarnadasse, Sadik,Dehmani, Younes

• (2020/09/09)
• 

• Facile synthesis of B/g-C3N4composite materials for the continuous-flow selective photo-production of acetone
• In this work versatile boron-carbon nitride composite materials were synthesized and utilized in a sustainable process using sunlight as the energy source for the continuous-flow selective photocatalytic production of acetone from 2-propanol. It is worth highlighting that the sample preparation was carried out by an environmentally friendly strategy, without a solvent or additional reagents. Samples containing boron in 1-10 wt% were subjected to physico-chemical characterization using XRD, porosimetry, UV-visible spectroscopy, TEM, energy-dispersive X-ray spectroscopy and XPS. The reaction output was analyzed on the basis of the reaction rate, selectivity and quantum efficiency of the process. A correlation analysis between catalytic properties with two observables, the boron phase distribution in the materials and charge handling efficiency (measured using photoluminescence), rationalizes photoactivity. Such an analysis indicates that the presence of an amorphous boron metallic phase and its contact with the carbon nitride component are key to setting up a renewable and easily scalable chemical process to obtain acetone.
• Caudillo-Flores, Uriel,Fernández-García, Marcos,Kubacka, Anna,Luque, Rafael,Mu?oz-Batista, Mario J.,Rodríguez-Padrón, Daily

• p. 4975 - 4984

  (2020/08/25)
• 

• Electrocatalytic performance of Pt-Ni nanoparticles supported on an activated graphite electrode for ethanol and 2-propanol oxidation
• Platinum (Pt) and platinum-nickel (Pt-Ni) electrocatalysts were prepared on activated graphite electrodes by an electrochemical deposition process. The electrocatalysts were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The electrocatalytic activity of the prepared electrocatalysts, their stability, and the effect of temperature toward ethanol and 2-propanol oxidation were evaluated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS). The results showed that the Pt-Ni/C exhibited higher catalytic activity, better stability and better tolerance to poisoning by ethanol and 2-propanol oxidation intermediate species compared to Pt/C, which was interpreted as synergistic and electronic effects between Pt and Ni. A study of the temperature dependence of ethanol and 2-propanol oxidation in the temperature range of 298-318 K, shows that the apparent activation energy for ethanol and 2-propanol oxidation on Pt-Ni/C was lower than on Pt/C. The results also revealed that the electro-oxidation of ethanol and 2-propanol on Pt/C were improved by raising the temperature and Ni modification.
• Chelaghmia,Nacef,Fisli,Affoune,Pontié,Makhlouf,Derabla,Khelifi,Aissat

• p. 36941 - 36948

  (2020/10/19)
• 

• Development of a method for the synthesis of basic catalysts with high number of active species
• Mesoporous silica MCF and metalosilicates Nb/MCF-14 and Ce/MCF-14 were modified with anchoring of melamine followed by (3-chloropropyl)trimethoxysilane functionalization. The texture/structure parameters, chemical composition and surface properties of synthesized samples were investigated by XRD, N2 adsorption/desorption, XPS, UV–vis, TG, elemental analysis and 2-propanol dehydration and dehydrogenation, whereas the activity of obtained catalysts was tested in the Knoevenagel condensation between benzaldehyde and malononitrile. The Knoevenagel reaction required the presence of basic active sites or a pair of acid-base active centers. The novelty of the presented work was the use of mesoporous cellular foam (MCF) also modified with niobium (Nb/MCF-14) or cerium species (Ce/MCF-14) as supports for melamine anchoring. The use of the mentioned supports allowed the investigation of the role of open structure of MCF and metal dopant on melamine loading, its stability and reactivity in the Knoevenagel condensation. The obtained results clearly demonstrate that cerium and niobium species loaded into MCF increase significantly the efficiency of melamine loading as well as its stability. The anchoring of melamine to silica and metalosilicates increase the activity of this modifier as a result of formation of secondary amine species. The presence of defected ceria in Mel/Ce/MCF-14 raises the basicity of anchored melamine due to the electron donating effect of ceria. Consequently, the amine species in melamine are more active in the Knoevenagel condensation than those in Mel/Nb/MCF-14 because niobium species do not change oxidation state as easily as defected ceria.
• Stawicka, Katarzyna

• p. 51 - 60

  (2019/09/30)
• 

• Catalytic conversion of propan-2-ol and butan-2-ol on carbon nanotubes with different carbon structures Evgeniya
• Cylindrical and conical carbon nanotubes were used as catalysts for the conversion of C3–C4 secondary aliphatic alcohols. The effect of the oxidative and reductive treatment of carbon nanotubes on the catalytic activity, selectivity and the conversion of propan-2-ol and butan-2-ol related to the structure of carbon matrix was revealed.
• Arkhipova, Ekaterina A.,Chernyak, Sergey A.,Ivanov, Anton S.,Lunin, Valery V.,Savilov, Sergey V.,Tveritinova, A.,Zhitnev, Yurii N.

• p. 355 - 358

  (2020/06/19)
• 

• Catalytic Conversion of Isopropanol on a Heteropoly Acid–η-Aluminum Oxide System
• Abstract: The results from catalytic conversion of isopropanol on a heteropoly acid–η-aluminum oxide system are discussed. It is established that modification increases its activity and selectivity toward oxygen-containing products. Based on a comparative analysis of reaction products, it is shown that the active sites of unmodified η-aluminum oxide consist only of strong Lewis acid sites (LASes) and strong Lewis basic sites (LBSes), represented predominantly by Br?nsted basic sites (BBSes) after modification with a heteropoly acid. The synthesized systems are characterized via X-ray diffraction, scanning electron microscopy, elemental analysis, and IR spectroscopy. The set of obtained results shows that the Keggin structure decomposes as it interacts with the basic oxide to form heteropoly anions. Due to their negative charge, these interact with the electron-accepting Lewis acid sites to form a surface–ligand complex. This then begins to act as a new Br?nsted base, due to its uncompensated negative charge.
• Guseinova,Adzhamov, K. Yu.,Yusubova

• p. 301 - 309

  (2020/04/10)
• 

• DECOMPOSITION OF ORGANIC PEROXIDES AND HYDROGEN PEROXIDE BY THE IRON THIOLATES AND RELATED COMPLEXES
• Disclosed herein is a method of reducing or disproportionating peroxide, comprising combining an organic chalcogenide, an iron salt, and the peroxide in the presence of an additional reductant, which can be the organic chalcogenide. The method can be used to, e.g., prepare alcohols from peroxides and to disproportionate hydrogen peroxide into water and oxygen.
• -
• Paragraph 0731; 0733; 0773-0775; 0781-0782

  (2020/07/04)
• 

• Imine containing C2-Symmetric chiral half sandwich η6-p-cymene-Ru(II)- phosphinite complexes: Investigation of their catalytic activity in the asymmetric transfer hydrogenation of ketones
• New chiral C2-symmetric bis(phosphinite) ligands containing imine group were synthesized from 1-({[(1R,2R)-2-{[(2-hydroxynaphthalen-1-yl)methylidene] amino}cyclohexyl]- imino}methyl)- naphthalen-2-ol and two equivalents of Ph2PCl, (i-Pr)2PCl or (Cy)2PCl, in high yields. Binuclear C2-symmetric half sandwich η6-p-cymene-Ru(II) complexes of the chiral phosphinite ligands were synthesized by treating of [Ru(η6-p-cymene)(μ-Cl)Cl]2 with the phosphinites in 1:1 M ratio in CH2Cl2. Their catalytic activities in asymmetric transfer hydrogenation (ATH) were investigated for the reaction of acetophenone derivatives with isopropyl alcohol. The corresponding optically active secondary alcohols were obtained in excellent levels of conversion (96–99%) and moderate enantioselectivity (up to 60% ee). Among three complexes investigated, complex 4 was the most efficient one.
• Saleh, Najmuldain Abdullah,Pa?a, Salih,Kayan, Cezmi,Meri?, Nermin,Sünkür, Murat,Aral, Tar?k,Aydemir, Murat,Baysal, Ak?n,Durap, Feyyaz

• (2019/10/08)
•