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Isobutanol and methanol synthesis on copper catalysts supported on modified magnesium oxide
Alcohols are selectively produced from CO/H2 on K-CuMgCeOx catalysts, but synthesis rates are strongly inhibited by CO2 formed during reaction. Reaction pathways involve methanol synthesis on Cu, chain growth to C2+ alcohols, and metal-base bifunctional coupling of alcohols to form isobutanol. Ethanol reactions on K-Cu0.5Mg5CeOx show that Cu catalyzes both alcohol dehydrogenation and aldol condensation reactions. CeO2 increases Cu dispersion and MgO surface area and K decreases Cu dispersion, but increases the density of basic sites. Reactions of acetaldehyde and 13C-labeled methanol lead to 1-13C-propionaldehyde, a precursor to isobutanol. The density and strength of basic sites were measured using a 12CO2/13CO2 isotopic jump method that probes the number and chemical properties of basic sites available at typical isobutanol synthesis temperatures. K or CeO2 addition to CuMgOx increases the density and strength of basic sites and the rates of base-catalyzed ethanol condensation reactions leading to acetone and n-butyraldehyde. The presence of CO in the He carrier during temperature-programmed surface reactions of ethanol preadsorbed on Cu0.5Mg5CeOx decreases the rate of base-catalyzed condensation reactions of preadsorbed ethanol, possibly due to the poisoning of basic and Cu sites by the CO2 formed from CO via water-gas shift reactions.
Xu, Mingting,Gines, Marcelo J. L.,Hilmen, Anne-Mette,Stephens, Brandy L.,Iglesia, Enrique
p. 130 - 147
(1997)
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An In-Situ Self-regeneration Catalyst for the Production of Renewable Penta-1,3-diene
Catalyst deactivation is a problem of great concern for many heterogeneous reactions. Here, an urchin-like LaPO4 catalyst was easily developed for pentane-2,3-diol dehydration; it has an impressive ability to restore the activity in situ by itself during the reaction, accounting for its high stability. This facilitates the efficient production of renewable penta-1,3-diene from pentane-2,3-dione via a novel approach, where penta-2,3-diol was obtained as an intermediate in 95 % yield under mild conditions.
Feng, Ruilin,Qi, Yanlong,Liu, Shijun,Cui, Long,Dai, Quanquan,Bai, Chenxi
p. 9495 - 9498
(2021)
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Van Volkenburgh et al.
p. 3595
(1949)
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Bailey et al.
p. 2997
(1972)
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SOME THERMAL TRANSFORMATION CHARACTERISTICS OF DIHYDROSYLVAN
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Karakhanov, E. A.,Karzhavina, N. P.,Brezhnev, L. Yu.
p. 191 - 192
(1982)
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Oxidation by a "H2O2-vanadium complex-pyrazine-2-carboxylic acid" reagent 5. Oxidation of lower alkanes with the formation of carbonyl compounds
Lower alkanes (ethane, propane, n-butane, n-pentane) are readily oxidized in acetonitrile solvent by H2O2 with vanadate anion - pyrazine-2-carboxylic acid (PCA), as the catalyst at 75 deg C and pressure of ca. 3 atm to produce predominantly or exclusively ketones (aldehydes).Isobutane is transformed selectively into tert-butyl alcohol.The oxidation of cyclohexane at 26 deg C in acetone or acetic acid is less efficient than in acetonitrile.The reaction does not occur in tert-butyl alcohol.
Shul'pin, G. B.,Drago, R. S.,Gonzalez, M.
p. 2386 - 2388
(1996)
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Catalytic aerobic oxidation of alcohols by Fe(NO3)3-FeBr3
Selective aerobic oxidation of secondary and benzylic alcohols was efficiently accomplished by the binary catalyst system Fe(NO3)3-FeBr3 under air at room temperature. The oxidation developed in mild conditions and showed
Martín, Sandra E,Suárez, Darío F
p. 4475 - 4479
(2002)
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A structure/catalytic activity study of gold(i)-NHC complexes, as well as their recyclability and reusability, in the hydration of alkynes in aqueous medium
We conducted a structure/catalytic activity study of water-soluble gold(i) complexes-supporting sulfonated NHC ligands-in the hydration of alkynes in pure water or water nsp;:nsp;methanol (1nsp;:nsp;1), as well as their recyclability. Comparative studies were carried out with the addition of different silver salts. Our results indicate that the bulkier complex is the most effective and that the addition of methanol as co-solvent not only shortens reaction times but also stabilizes the less bulky complexes.
Fernández, Gabriela A.,Chopa, Alicia B.,Silbestri, Gustavo F.
p. 1921 - 1929
(2016)
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Relative and absolute kinetic studies of 2-butanol and related alcohols with tropospheric Cl atoms
A newly constructed chamber/Fourier transform infrared system was used to determine the relative rate coefficient, ki, for the gas-phase reaction of Cl atoms with 2-butanol (k1), 2-methyl-2-butanol (k 2), 3-methyl-2-butanol (k3), 2,3-dimethyl-2-butanol (k4) and 2-pentanol (k5). Experiments were performed at (298 ± 2) K, in 740 Torr total pressure of synthetic air, and the measured rate coefficients were, in cm3 molecule-1 s -1 units (±2σ): k1 = (1.32 ± 0.14) × 10-10, k2 = (7.0 ± 2.2) × 10 -11, k3 = (1.17 ± 0.14) × 10-10, k4 = (1.03 ± 0.17) × 10-10 and k5 = (2.18 ± 0.36) × 10-10, respectively. Also, all the above rate coefficients (except for 2-pentanol) were investigated as a function of temperature (267-384 K) by pulsed laser photolysis-resonance fluorescence (PLP-RF). The obtained kinetic data were used to derive the Arrhenius expressions: k1(T) = (6.16 ± 0.58) × 10 -11exp[(174 ± 58)/T], k2(T) = (2.48 ± 0.17) × 10-11exp[(328 ± 42)/T], k3(T) = (6.29 ± 0.57) × 10-11exp[(192 ± 56)/T], and k 4(T) = (4.80 ± 0.43) × 10-11exp[(221 ± 56)/T] (in units of cm3 molecule-1 s-1 and ±σ). Results and mechanism are discussed and compared with the reported reactivity with OH radicals. Some atmospheric implications derived from this study are also reported. This journal is the Owner Societies.
Ballesteros, Bernabe,Garzon, Andres,Jimenez, Elena,Notario, Alberto,Albaladejo, Jose
p. 1210 - 1218
(2007)
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A thermodynamic study of the ketoreductase-catalyzed reduction of 2-alkanones in non-aqueous solvents
Equilibrium constants K have been measured for the reactions (2-alkanone + 2-propanol = 2-alkanol + acetone), where 2-alkanone = 2-butanone, 2-pentanone, 2-hexanone, 2-heptanone, and 2-octanone and 2-alkanol = 2-butanol, 2-pentanol, 2-hexanol, 2-heptanol, and 2-octanol. The solvents used were n-hexane, toluene, methyl tert-butyl ether (MTBE), and supercritical carbon dioxide SCCO 2 (pressure P - 10.0 MPa). The temperature range was T - (288.15 to 308.27) K. Chiral analysis of the reaction products showed that the enzyme used in this study was stereoselective for the 2-octanone reaction system, i.e. only (S)-(+)-2-octanol was formed. For the reactions involving butanone, pentanone, and hexanone, the products were racemic mixtures of the respective (S)-(+)-2-alkanol and the (R)-(-)-2-alkanol. Chiral analysis showed that for the 2-heptanone reaction system, the 2-alkanol product was a mixture of (S)-(+)-2-heptanol and (R)-(-)-2-heptanol, at the respective mole fractions of 0.95 and 0.05. The equilibrium constant for the reaction system involving 2-butanone carried out in n-hexane was measured at several temperatures. For this reaction, the values for the thermodynamic reaction quantities at T= 298. 15 K are: K= 0.838±0.013; the standard molar Gibbs free energy change ΔrgHm° = (0.44±0.040) kJ · mol-1; the standard molar enthalpy change ΔrgHm° = -(1.2±1.7) kJ mol-1, and the standard molar entropy change ΔrgHm° = -(5.5±5.7) J K-1 mol-1. Interestingly, inspection of the values of the equilibrium constants for these reactions carried out in n-hexane, toluene, MTBE, and SCCO2 shows that these values are comparable and have little dependence on the solvent used to carry out the reaction. The values of the equilibrium constants decrease monotonically with increasing value of the number of carbons Nc and trend towards a limiting value of ≈0.30 for Nc > 8. Published by Elsevier Ltd.
Tewari, Yadu B.,Schantz, Michele M.,Phinney, Karen W.,Rozzell, J. David
p. 89 - 96
(2005)
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Developing an efficient catalyst for controlled oxidation of small alkanes under ambient conditions
The tricopper complex [CuICuICuI(7-N- Etppz)]1+, where 7-N-Etppz denotes the ligand 3,3′-(1,4- diazepane-1,4-diyl)bis[1-(4-ethyl piperazine-1-yl)propan-2-ol], is capable of mediating facile conversion of methane into methanol upon activation of the tricopper cluster by dioxygen and/or HO at room temperature. This is the first molecular catalyst that can catalyze selective oxidation of methane to methanol without over-oxidation under ambient conditions. When this CuICu ICuI tricopper complex is activated by dioxygen or H 2O2, the tricopper cluster harnesses a "singlet oxene", the strongest oxidant that could be used to accomplish facile O-atom insertion across a C-H bond. To elucidate the properties of this novel catalytic system, we examine here methane oxidation over a wider range of conditions and extend the study to other small alkanes, including components of natural gas. We illustrate how substrate solubility, substrate recognition and the amount of H2O2 used to drive the catalytic oxidation can affect the outcome of the turnover, including regiospecificity, product distributions and yields of substrate oxidation. These results will help in designing another generation of the catalyst to alleviate the limitations of the present system. This journal is the Partner Organisations 2014.
Nagababu, Penumaka,Yu, Steve S.-F.,Maji, Suman,Ramu, Ravirala,Chan, Sunney I.
p. 930 - 935
(2014)
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Product distributions from the OH radical-induced oxidation of n-Pentane and isopentane (2-Methylbutane) in Air
Hydroxyl radicals, generated by photolysis of H2O2. were reacted with n-pentane and isopentane in air in the absence of nitrogen oxides. The observed product distributions were compared with similar data derived by computer simulations, based on the known reaction mechanisms, to determine relative probabilities for hydrogen abstraction at different sites of the parent compounds and to estimate branching ratios and relative rate coefficients for cross-combination reactions between different peroxy radicals. For n-pentane. the distribution of the pentanols indicates probabilities for hydrogen abstraction, in percent, of q1= 9.1 ± 0.7. q 2 = 56.1 ± 1.8, and q3 = 34.8 ± 1.3. which agree with predictions based on the algorithm proposed by Atkinson. Branching ratios needed to harmonize calculated and observed product distributions are somewhat larger than, although still within the error ranges of. the values found by us previously Comparison between experimental and calculated data confirms the isomerization and decomposition constants recently established for the three pentoxyl radical isomers. The product distribution for isopentane. which is dominated by acetone, acetaldehyde. 2-methyl-butan-2-ol. and 2-methyl-butan-2-hydroperoxide, is in harmony with the predicted oxidation mechanism. Probabilities for hydrogen abstraction from isopentane were estimated to occur to 12% at the primary. 28% at the secondary, and 60% at the tertiary sites, again in agreement with predictions based on the algorithm of Atkinson.
Heimann, Gerald,Warneck, Peter
p. 677 - 688
(2006)
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Grove,J.F.
p. 2261 - 2263
(1971)
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Reactions in the Photocatalytic Conversion of Tertiary Alcohols on Rutile TiO2(110)
According to textbooks, tertiary alcohols are inert towards oxidation. The photocatalysis of tertiary alcohols under highly defined vacuum conditions on a titania single crystal reveals unexpected and new reactions, which can be described as disproportionation into an alkane and the respective ketone. In contrast to primary and secondary alcohols, in tertiary alcohols the absence of an α-H leads to a C?C-bond cleavage instead of the common abstraction of hydrogen. Surprisingly, bonds to methyl groups are not cleaved when the alcohol exhibits longer alkyl chains in the α-position to the hydroxyl group. The presence of platinum loadings not only increases the reaction rate but also opens up a new reaction channel: the formation of molecular hydrogen and a long-chain alkane resulting from recombination of two alkyl moieties. This work demonstrates that new synthetic routes may become possible by introducing photocatalytic reaction steps in which the co-catalysts may also play a decisive role.
Courtois, Carla,Eder, Moritz,Schnabl, Kordula,Walenta, Constantin A.,Tschurl, Martin,Heiz, Ulrich
p. 14255 - 14259
(2019)
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Enantioselective oxidation of secondary alcohols by the flavoprotein alcohol oxidase from Phanerochaete chrysosporium
The enantioselective oxidation of secondary alcohols represents a valuable approach for the synthesis of optically pure compounds. Flavoprotein oxidases can catalyse such selective transformations by merely using oxygen as electron acceptor. While many flavoprotein oxidases preferably act on primary alcohols, the FAD-containing alcohol oxidase from Phanerochaete chrysosporium was found to be able to perform kinetic resolutions of several secondary alcohols. By selective oxidation of the (S)-alcohols, the (R)-alcohols were obtained in high enantiopurity. In silico docking studies were carried out in order to substantiate the observed (S)-selectivity. Several hydrophobic and aromatic residues in the substrate binding site create a cavity in which the substrates can comfortably undergo van der Waals and pi-stacking interactions. Consequently, oxidation of the secondary alcohols is restricted to one of the two enantiomers. This study has uncovered the ability of an FAD-containing alcohol oxidase, that is known for oxidizing small primary alcohols, to perform enantioselective oxidations of various secondary alcohols.
Tjallinks, Gwen,Martin, Caterina,Fraaije, Marco W.
(2021)
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Rhodium(I)-Catalyzed Biphasic Isomerization of Allylic Alcohols
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Alper, Howard,Hachem, Khaled
p. 2269 - 2270
(1980)
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Wet carbon-based solid acid/potassium bromate as an efficient heterogeneous reagent for oxidation of alcohols under mild conditions
Wet carbon-based solid acid and potassium bromate were used as new reagent for oxidation of alcohols to their corresponding aldehyde or ketone derivatives in dichloromethane with good yields. Copyright Taylor & Francis Group, LLC.
Zali, Abbas,Shokrolahi, Arash
p. 1064 - 1069
(2008)
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Stereochemistry of the Hydrogenolysis of Oxacycloalkanes on Metal Catalysts
On the basis of reaction kinetics, H-D exchange, and i.r. studies of the hydrogenolysis of oxirans and oxolans, the opposite regio- and stereo-selectivities of Pt and Ni are interpreted, a new reaction mechanism is proposed, and it is shown experimentally that the reaction mechanism depends inter alia on the steric structure of the molecule.
Bartok, Mihaly,Notheisz, Ferenc
p. 667 - 668
(1980)
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Bifunctional condensation reactions of alcohols on basic oxides modified by copper and potassium
Alcohol dehydrogenation and condensation reactions are involved in chain growth pathways on Cu/MgCeOx promoted with potassium. These pathways lead to the formation of isobutanol with high selectivity via reactions of higher alcohols with methanol-derived C1 species in reaction steps also relevant to higher alcohol synthesis from CO/H2 mixtures at higher pressures on K-Cu/MgCeOx catalysts. Ethanol reactions on K-CUyMg5CeOx show that both Cu and basic sites participate in alcohol dehydrogenation and aldol condensation steps leading to n-butyraldehyde and acetone. Chain growth occurs by condensation reactions involving a metal-base bifunctional aldol-type coupling of alcohols. Reactions of 12C2H5OH-13C2H 4O mixtures show that direct condensation reactions of ethanol can occur without requiring the intermediate formation of gas phase acetaldehyde. Reactions of C2H5OH/D2 mixtures show that Cu sites increase the rate of aldol condensation by introducing recombinative desorption sites that remove hydrogen atoms formed in C-H activation steps leading to the unsaturated aldol-type species required for chain growth. Reactions of acetaldehyde and 13C-labeled methanol lead predominantly to 1-13C-propionaldehyde and 2-13C-isobutyraldehyde, both of which lead to isobutanol during CO/H2 reactions. Mixtures of propionaldehyde and 13C-labeled methanol lead to singly-labeled isobutyraldehyde. Chain growth to C2+ alcohols occurs via addition of a methanol-derived C1 species to adsorbed oxygen-containing intermediates. The gradual appearance of 13C in the unlabeled reactant within these mixtures shows that aldol coupling reactions are reversible. Reverse aldol condensation reactions after intramolecular hydride transfer lead to the formation of acetone from ethanol. Isobutyraldehyde is a preferred end-product of aldol-type chain growth reactions of alcohols because it lacks the two α-hydrogens required for subsequent chain growth. 998 Academic Press.
Gines, Marcelo J. L.,Iglesia, Enrique
p. 155 - 172
(1998)
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A versatile bi-metallic copper-cobalt catalyst for liquid phase hydrogenation of furfural to 2-methylfuran
Liquid phase hydrogenation of furfural (FFR) to 2-methyl furan (2-MF) was examined using noble metal free, Cr-free, bi-metallic Cu-Co catalysts. Three supported bi-metallic catalysts (Cu-Co/SiO2, Cu-Co/H-ZSM-5, and Cu-Co/γ-Al2O3) with various Cu/Co molar ratios (x/y = 1, 2, and 4) with fixed Cu loading (x = 10 wt%) were prepared by the impregnation method. The physico-chemical properties of various catalysts were studied by using XRD, N2-sorption, SEM, TEM, TPR, TPD, XANES/EXAFS and CHNS methods. The results confirmed the formation of spinel CuCo2O4 oxides, and much higher dispersion of Cu on acidic supports such as H-ZSM-5 and γ-Al2O3. However, the absence of a spinel CuCo2O4 oxide was observed in Cu-Co/SiO2via XANES/EXAFS results. XRD and TEM results revealed the formation of bigger Cu particles in Cu-Co/SiO2. In the catalytic activity studies, Cu-Co/γ-Al2O3 catalyzed the hydrogenation of furfural with 98.8% conversion, resulting in maximal selectivity of 2-MF due to the presence of maximal Cu-CoOx sites. The H-ZSM-5 supported catalyst had marginally less 2-MF selectivity, whereas the silica supported catalyst exhibited maximum selectivity towards furfuryl alcohol (FOL) because of the large copper particles. H2-TPR and EXAFS results revealed that the incorporation of cobalt metal improves the reducibility of Cu-catalysts, thus improving the catalytic activity. Bi-metallic Cu-Co/γ-Al2O3 catalysts displayed higher activity as compared to their monometallic counterpart, and Cu-Co/γ-Al2O3 (x/y = 1) exhibited the best catalytic performance with 78% selectivity to 2-MF at 220°C and 4 MPa.
Srivastava, Sanjay,Jadeja,Parikh, Jigisha
p. 1649 - 1658
(2016)
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Oxidation of Alcohols with H2O2 Catalyzed by Titanium Silicalite-1
Primary and secondary alcohols are oxidised by H2O2 in the presence of titanium silicalite-1 to carbonylic compounds.Reaction rates follow the general trend secondary primary methanol.Rates are sensitive to position effects of the OH group, to chain branching effects, and to molecular size of the alcohol.Kinetic orders with respect to H2O2 are generally close to zero, while those with respect to the alcohol are strongly affected by the solvent used.The kinetic pattern is interpreted in terms of an interaction of the lattice titanium atom of titanium silicalite-1 with H2O2.The kinetic order with respect to the alcohol can be interpreted either in terms of titanium-alcohol adducts or with a selective alcohol sorption in the catalyst pores.The reaction pattern is consistent with a process taking place essentially inside the zeolite channels, with a transition-state-restricted shape-selectivity.The nature of the titanium hydroperoxide involved in the intermediate complex is discussed.
Maspero, Federico,Romano, Ugo
p. 476 - 482
(1994)
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[α-PW12O40]3- immobilized on ionic liquid-modified polymer as a heterogeneous catalyst for alcohol oxidation with hydrogen peroxide
Ionic liquid-modified polystyrene resin beads were demonstrated to be an appropriate support for polyoxometalate. In this heterogeneous catalytic system, alcohols can be efficiently oxidized to corresponding carbonyl groups with H2O2 in CH3CN. The catalyst can be easily recovered by filtration and recycled without apparent loss of catalytic performance. Copyright Taylor & Francis Group, LLC.
Lang, Xianjun,Li, Zhen,Xia, Chungu
p. 1610 - 1616
(2008)
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New efficient aerobic oxidation of some alcohols with dioxygen catalysed by N-hydroxyphtalimide with vanadium co-catalysts
New efficient vanadium co-catalysts have been developed for the oxidation of some alcohols with O2 catalysed by N-hydroxyphthalimide (NHPI). Various alcohols (primary and secondary) were selectively oxidized by O 2 under mild conditions in the presence of a catalytic amount of NHPI as a radical-producing agent combined with small amounts of vanadium complexes with or without the addition of a simple salt (e.g. LiCl) or base (e.g. pyridine).
Figiel, Pawel J.,Sobczak, Jaroslaw M.,Ziolkowski, Jozef J.
p. 244 - 245
(2004)
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Highly selective C=C bond hydrogenation in α,β-unsaturated ketones catalyzed by hectorite-supported ruthenium nanoparticles
Metallic ruthenium nanoparticles intercalated in hectorite (particle size ～7 nm) were found to catalyze the specific hydrogenation (conversion 100%, selectivity > 99.9%) of the carbon-carbon double bond in α,β- unsaturated ketones such as 3-buten-2-one, 3-penten-2-one, 4-methyl-3-penten-2- one. The catalytic turnovers range from 765 to 91,800, the reaction conditions being very mild (temperature 35 °C and constant hydrogen pressure 1-10 bar). After a catalytic run, the catalyst can be recycled and reused without loss of activity and selectivity
Khan, Farooq-Ahmad,Vallat, Armelle,Süss-Fink, Georg
p. 168 - 173
(2012)
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Photodecomposition of iodopentanes in air: Product distributions from the self-reactions of n-pentyl peroxyl radicals
Product distributions from the 254-nm photooxidation of the three iodopentane isomers were explored as a technique for studying the self-reactions of individual pentyl peroxyl radicals (in air at ambient temperature and pressure). Pentanols and the associated carbonyl compounds (pentanal or pentanones) were major products as expected. Other major products resulted from the isomerization of pentan-1-oxyl and pentan-2-oxyl radicals, but their nature could not be identified. Minor products were alcohols and carbonyl compounds arising from the decomposition of pentoxyl radicals. Diols and mixed hydroxycarbonyl compounds from cross-combination reactions were essentially absent, in contrast to expectation. The observed product distributions were evaluated to derive branching ratios for the radical-preserving pathways of the self-reactions, 0.42 ± 0.17, 0.46 ± 0.10, 0.39 ± 0.08, for pentan-1-yl peroxyl, pentan-2-yl peroxyl, and pentan-3-yl peroxyl, respectively. Rate coefficients derived for the decomposition of the corresponding pentoxyl radicals, relative to their reaction with oxygen, are (5.1 ± 0.5) × 1018, (1.0 ± 0.2) × 1018, and (3.2 ± 0.3) × 1018 molecule cm-3, respectively. Rate constants for the isomerization of pentan-1-oxyl and pentan-2-oxyl were estimated from the contributions of isomerization products to the total amounts of products as (4.0 ± 1.1) × 105 s-1 and (1.0 ± 2.0) × 105 s-1, respectively.
Heimann, Gerald,Benkelberg, Heinz-Jrgen,Bge, Olaf,Warneck, Peter
p. 126 - 138
(2002)
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Bioorganometallic chemistry: Co-factor regeneration, enzyme recognition of biomimetic 1,4-NADH analogs, and organic synthesis; tandem catalyzed regioselective formation of N-substituted-1,4-dihydronicotinamide derivatives with [Cp*Rh(bpy)H]+, coupled to chiral S-alcohol formation with HLADH, and engineered cytochrome P450s, for selective C-H oxidation reactions
Two novel tandem catalysis approaches for the chiral synthesis of S-alcohols from reduction of their prochiral ketones with Horse Liver Alcohol Dehydrogenase (HLADH), and selective C-H oxidation reactions with protein engineered Cytochrome P450s, are presented. We utilized a co-factor regeneration procedure with three biomimetic NAD+ models that do not contain the pyrophosphate, nor the adenosine group, and either/or a ribose, N-1-benzylnicotinamide triflate, 1, N-4-methoxybenzylnicotinamide triflate, 2, and β-nicotinamide-5′-ribose methyl phosphate, 3, in conjunction with in situ formed [Cp*Rh(bpy)H]+ from [Cp*Rh(bpy)(H2O)]2+ (Cp*?=?η5-C5Me5, bpy?=?2,2'-bipyridyl) and the hydride source, sodium formate, to regioselectively provide their 1,4-NADH analogs, N-benzyl-1,4-dihydronicotinamide, 4, N-4-methoxybenzyl-1,4-dihydronicotinamide, 5, and 1,4-dihydronicotinamide-5′-ribose methylphosphate, 6. Surprisingly, the 1,4-NADH biomimics, 4 and 6, were recognized, in the second tandem catalysis approach, by the natural 1,4-NADH dependent enzyme, HLADH, for catalyzed, highly enantioselective conversions of prochiral ketones to chiral S-alcohols. For example, with phenethylmethyl ketone and benzylmethyl ketone, the corresponding chiral alcohols were formed in >93% ee (S-enantiomer). Thus, 1,4-NADH biomimetic model recognition by HLADH does not significantly depend on the presence of the ribose, pyrophosphate, or adenosine groups to provide chiral products. We will also propose a plausible active site (HLADH)Zn-H intermediate, generated via a hydride transfer from bound 4/6 to Zn, for the enzymatic reduction of prochiral aryl/alkyl ketones to their chiral aryl/alkyl S-alcohols. Furthermore, the use of protein engineered cytochrome P450 enzymes provided improved molecular recognition of the above mentioned 1,4-NADH biomimetic co-factors, 4 and 5, for selective C-H oxidation reactions. For example, 1,4-NADH dependent mutants of natural 1,4-NAD(P)H dependent P450 BM-3 and 1,4-NADH dependent P450 CAM, with biomimetic co-factors 4 and 5, provided selective oxidation of p-nitrophenoxydecanoic acid to ω-oxydecanocarboxylic acid and p-nitrophenol, via C-H hydroxylation and β-hydrogen elimination, while oxidation of camphor provided hydroxycamphor, respectively. We will discuss the various parameters that effect molecular recognition of the biomimics, including protein engineering of both P450 BM-3 and P450 CAM enzymes, while determining the effect of the co-factor regeneration procedure on HLADH and P450 enzyme activity. These important observations have created new paradigms for the synthesis of organic compounds of interest, with the economically more favorable biomimics of NAD+, 1,4-NADH, and 1,4-NAD(P)H as co-factors, in tandem with the use of [Cp*Rh(bpy)(H)]+ as a regioselective catalytic reagent for co-factor regeneration.
Lo, H. Christine,Ryan, Jessica D.,Kerr, John B.,Clark, Douglas S.,Fish, Richard H.
p. 38 - 52
(2017)
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A novel method for the synthesis of aldehydes and ketones
A new method for the preparation of aldehydes and ketones from alkylnitrites and BF2.Et2O or anhydrous ZnCl2 is described. Twelve different nitrites were tested obtaining yields over 90%. When these Lewis acids were substituted by anhydrous AlCl3, the yield decreased to a value below 20%.
Pérez G.,Pérez G.,Zavala S.,Pérez G.,Guadarrama M.
p. 3011 - 3014
(1998)
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Cr-free Cu-catalysts for the selective hydrogenation of biomass-derived furfural to 2-methylfuran: The synergistic effect of metal and acid sites
Our work focuses on exploring Cr-free Cu-catalysts for the highly efficient conversion of biomass-derived furfural to value-added bio-fuel 2-methylfuran. Three supported Cu-catalysts (Cu/SiO2, Cu/Al2O3, and Cu/ZnO) were prepared by the typical precipitation method, and Cu/SiO2 catalyst exhibited the best catalytic performance with an 89.5% yield to 2-MF. A series of characteristic results indicated that the high yield of 2-methylfuran on Cu/SiO2 catalyst was assigned to synergistic effect of metal and the weak acid sites. Among them, Cu/ZnO catalyst exhibited maximum furfuryl alcohol selectivity because of the large Cu particles, while Cu/Al2O3 catalyst had low 2-methylfuran selectivity due to the insufficient weak acid sites. For Cu/SiO2 catalyst, the highly dispersed Cu particles and the strong metal-support interaction are propitious to its superior catalytic activity. Therefore, copper species are composed on different supports as a result of the different interaction of metal-support to affect their catalytic activity, while products selectivity is related to the acidic property of catalyst. In addition, temperature programmed desorption of furfural indicated that the adsorption-desorption properties of catalyst surface species would influence the rate of furfural hydrogenation.
Dong, Fang,Zhu, Yulei,Zheng, Hongyan,Zhu, Yifeng,Li, Xianqing,Li, Yongwang
p. 140 - 148
(2015)
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A series second-first-order mechanism for the oxidation of primary and secondary alcohols by Cr(VI) reagents
Based on the experimental data, a definite mechanism for the oxidation of primary and secondary alcohols with PCC and two newly synthesized Cr(VI) reagents has been proposed. The reaction has been shown to be a series reaction rather than a simple one step reaction as reported in the literature. The mechanism proposed has been exemplified by taking 2-pentanol as an example. The kinetic isotope studies have also been performed.
Agarwal, Seema,Tiwari,Sharma
p. 1963 - 1974
(1990)
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REGIOSELECTIVE PREPARATION OF KINETIC TRIMETHYLSILYL ENOL ETHERS FROM β-KETO SILANES
Kinetic trimethylsilyl enol ethers were prepared regioselectively by the two-step method, i.e., trimethylsilyl triflate catalyzed rearrangement of β-keto silanes which were prepared from trimethylsilylmethylcopper and acid chlorides.
Yamamoto, Yohsuke,Ohdoi, Keisuke,Nakatani, Masayuki,Akiba, Kin-ya
p. 1967 - 1968
(1984)
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Green synthesis of low-carbon chain nitroalkanes via a novel tandem reaction of ketones catalyzed by TS-1
A green and efficient one-pot method has been developed for the synthesis of low-carbon chain nitroalkanes via a novel TS-1 catalyzed tandem oxidation of ketones with H2O2 and NH3. The tandem reaction including ammoxidation, oximation and oxidation of oximes, afforded up to 88% yield and 98% chemo-selectivity requiring only 90 min, at 70 °C and atmospheric pressure. Moreover, this method was even amenable to 100-fold scale-up without loss of chemical efficiency with 87% yield, represents a significant advance towards industrial production of nitroalkanes. Furthermore, the plausible mechanism of TS-1 catalyzed tandem oxidation of ketones to prepare nitroalkanes was proposed.
Chu, Qingyan,He, Guangke,Xi, Yang,Wang, Ping,Yu, Haoxuan,Liu, Rui,Zhu, Hongjun
p. 46 - 50
(2018)
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TRANSFORMATION OF ORGANIC COMPOUNDS IN THE PRESENCE OF METAL COMPLEXES I. TRANSFORMATION OF UNSATURATED ALCOHOLS WITH METAL COMPLEX CATALYSTS
The transformations of unsaturated alcohols (2-hexen-3-ol, 1-penten-4-ol, 1-penten-4-ol and 2-methylenecyclohexanol) were studied under identical experimental conditions in the presence of various Rh and Ru complexes (RhCl(PPh3)3, RhH(PPh3)4, RhCl3*3H2O, RhCl3*3H2O + PPh3, Rh(COD)Cl2, Rh(COD)Cl2 + PPh3, RhCl2(PPh3)3 and RuH2(PPh3)4).Several aspects of both the unsaturated alcohol and the complex exertconsiderable effects on the extent of the main reactions; isomerization to ketone and double-bond migration.
Felfoeldi, K.,Bartok, M.
p. C37 - C40
(1985)
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In operando XAS investigation of reduction and oxidation processes in cobalt and iron mixed spinels during the chemical loop reforming of ethanol
FeCo2O4 and CoFe2O4 nanoparticles have been studied as oxygen carriers for the Chemical Loop Reforming (CLR) of ethanol. By using in operando X-ray absorption spectroscopy we have followed in real time the chemical and structural changes that take place on the materials as a function of temperature and reactive atmosphere (i.e. ethanol/water streams). During the first step of CLR for both oxides the most active chemical species are the cations in the tetrahedral sites, irrespective of their chemical nature. Quite rapidly the spinel structure is transformed into a mix of wüstite-type oxide and metal alloys, but the formation of a metal phase is easier in the case of cobalt, while iron shows a marked preference to form wüstite type oxide. Despite the good reducibility of FeCo2O4 imparted by the high amount of cobalt, its performance in the production of hydrogen is quite poor due to an inefficient oxidation by water steam, which is able to oxidize only the outer shell of the nanoparticles. In contrast, CoFe2O4 due to the residual presence of a reducible wüstite phase shows a higher hydrogen yield. Moreover, by combining the structural information provided by X-ray absorption spectroscopy with the analysis of the byproducts of ethanol decomposition we could infer that FeCo2O4 is more selective than CoFe2O4 for the selective dehydrogenation of ethanol to acetaldehyde because of the higher amount of Fe(iii) ions in tetrahedral sites.
Carraro,Vozniuk,Calvillo,Nodari,La Fontaine,Cavani,Agnoli
p. 20808 - 20817
(2017)
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Reaction of metal alkoxides with 3-alkyl-substituted acetylacetone derivatives - Coordination vs. hydrodeacylation
Reaction of Ti(OiPr)4 or Zr(OPr)4 with 1 or 2 molar equiv of the 3-alkyl-substituted acetylacetone derivatives 3-acetyl-6-trimethoxysilylhexane-2-one or 3-acetylpentane-2-one not only gives the corresponding β-diketonate complexes but also results in about 15% hydrodeacylation of the β-diketone. With the stronger Lewis acid Al(O sBu)3 hydrodeacylation prevails. Hydrodeacylation is suppressed when a 1:5 ratio of metal alkoxide and β-diketone is reacted.
Puchberger, Michael,Rupp, Wolfgang,Bauer, Ulrike,Schubert, Ulrich
p. 1289 - 1294
(2004)
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Mn-trimethyltriazacyclononane/ascorbic acid: A remarkably efficient catalyst for the epoxidation of olefins and the oxidation of alcohols with hydrogen peroxide
The system comprised of manganese(II) acetate or sulfate, 1,4,7-trimethyl-1,4,7-triazacyclononane (TMTACN) and ascorbic acid efficiently catalyzes the epoxidation of olefins and the oxidation of alcohols with hydrogen peroxide. For example, in the presence of as little as 0.03 mol% of Mn2+, methyl acrylate is converted to its epoxide in 97% yield. Under the same conditions, 2-pentanol yielded 2-pentanone in almost quantitative yield. With E- and Z-1-deuterio-1-octene as substrates, the epoxidation was shown to proceed with almost exclusive (94±2%) retention of configuration.
Berkessel, Albrecht,Sklorz, Christoph A.
p. 7965 - 7968
(1999)
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Zeolite supported permanganate: An efficient catalyst for selective oxidation of enamines, alkylarenes and unsaturated alcohols
Potassium permanganate supported on zeolite can be used for the selective oxidation of various enamines, alkylarenes and unsaturated alcohols to the corresponding ketones, in good yield. Arenes were selectively oxidized at the benzylic position. If the benzylic carbon is secondary, ketones are obtained, and alcohols are produced if the benzylic position is tertiary. In contrast unsaturated secondary alcohols selectively undergo oxidation to the corresponding olefinic ketones without affecting the carbon-carbon double bonds.
Sreekumar,Padmakumar, Raghavakaimal
p. 5143 - 5146
(1997)
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Bassette,Day
p. 482
(1960)
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Meerwein
p. 249
(1913)
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A new strategy for the efficient synthesis of 2-methylfuran and γ-butyrolactone
A novel process involving the coupling of the hydrogenation of furfural and the dehydrogenation of 1,4-butanediol has been studied in the vapor phase for the synthesis of 2-methylfuran (2-MF) and γ-butyrolactone γ-BL) over the same Cu-based catalyst. It was found that hydrogen and heat energy are utilized with high efficiency in this process.
Zhu, Yu-Lei,Xiang, Hong-Wei,Li, Yong-Wang,Jiao, Haijun,Wu, Gui-Sheng,Zhong, Bing,Guo, Guang-Qing
p. 208 - 210
(2003)
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Controlled Monooxygenation of n- and Isoalkanes with Molecular Oxygen Catalyzed in Nonheme Iron Complex/Hydroquinone Systems
Linear and branched alkanes are monooxygenated with O2 in nonheme iron complex/hydroquinone systems.Selectivity to form either alcohols or carbonyl compounds was controlled by the pyridine concentration.Reactivity of dfferent types of C-H bonds was affected by the substituents of hydroquinones, suggesting that hydroquinones are located in the vicinity of an active center in the product formation step.
Funabiki, Takuzo,Kashiba, Koji,Toyoda, Takehiro,Yoshida, Satohiro
p. 2303 - 2306
(1992)
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Fry et al.
p. 1252
(1960)
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Djerassi et al.
(1960)
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Royals
p. 1508
(1945)
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A direct imaging of amphiphilic catalysts assembled at the interface of emulsion droplets using fluorescence microscopy
An amphiphilic fluorescent catalyst Q9[EuW10O 36] (Q = [(C18H37)2N +(CH3)2]), assembled in the interface of emulsion systems, was directly imaged by fluores
Gao, Jinbo,Zhang, Yongna,Jia, Guoqing,Jiang, Zongxuan,Wang, Shouguo,Lu, Hongying,Song, Bo,Li, Can
p. 332 - 334
(2008)
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Thermochemical Studies of Carbonyl Reactions. 2. Steric Effects in Acetal and Ketal Hydrolysis
A calorimetric determination of the enthalpies of hydrolysis of a series of alkyl-substituted dimethyl acetals is reported.These data are critically compared with the enthalpies of hydrolysis from an analogous set of aliphatic dimethyl ketals derived from 2-alkanones.The acetals exhibit a significantly attenuated range in their enthalpies of hydrolysis relative to that for ketal hydrolysis.The free energies of acetal formation in solution were modeled by measurements of the corresponding free energies of hemiacetal formation from the aldehydes in neutral methanol.The observed free-energy differences are satisfactorily correlated with the Taft Es steric substituent constant scale, but the corresponding acetal enthalpy data vary in a complex manner.The role of entropy in determining kinetic and equilibrium steric effects in a variety of other systems is discussed.Preliminary molecular mechanics calculations on these systems indicate the importance of bond angle bending in evaluating the torsional potential at a carbonyl group.Many of the compounds were found to possess several conformations having comparable energies.
Wiberg, Kenneth B.,Squires, Robert R.
p. 4473 - 4478
(1981)
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Decarboxylation and simultaneous reduction of silver(I) β-ketocarboxylates with three types of coordinations
A series of silver(I) β-ketocarboxylates were prepared by reaction of β-ketocarboxylic acids with silver nitrate in the presence of diethanolamine. The silver(I) β-ketocarboxylates decomposed over a narrow temperature range to form metallic silver, CO2, and the corresponding ketones. In addition, products derived from radical intermediates were detected by mass spectroscopic analysis for some silver(I) β-ketocarboxylates. Infrared and solid state 13C-NMR spectra of silver(I) β-ketocarboxylates suggested the presence of two types of structures involving a carbonyl group in addition to the dimeric eight-membered ring structure as in the structure of silver(I) stearate. The silver(I) β-ketocarboxylate model compound used was HCOCH2COOAg and its structures were determined using density functional theory (DFT) and atoms-in-molecules (AIM) methods. Three types of coordinations around the Ag ion differing significantly in Ag-O bond strengths were found. Based on the calculated structures and experimental results, the relationships between the structures and decomposition temperatures are discussed in terms of the thermal decomposition process.
Hatamura, Mariko,Yamaguchi, Shunro,Takane, Shin-Ya,Chen, Yu,Suganuma, Katuaki
p. 8993 - 9003
(2015)
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Kinetics and mechanism of the oxidation of alcohols by tetrapropylammonium perruthenate
2-Propanol is oxidized by tetrapropylammonium perruthenate (TPAP) in a reaction that is second order in TPAP and first order in 2-propanol. One of the products, believed to be ruthenium dioxide, is an effective catalyst for the reaction, making it an autocatalytic process. The rate of oxidation is relatively insensitive to the presence of substituents. Primary kinetic deuterium isotope effects are observed when either the hydroxyl or the α hydrogen is replaced by deuterium. The only product obtained from the oxidation of cyclobutanol is cyclobutanone, indicating that the reaction is a two-electron process. Tetrahydrofuran is oxidized at a rate that is several orders of magnitude slower than that observed for 2-propanol, suggesting that the reaction of TPAP with alcohols may be initiated by formation of perruthenate esters. A tentative mechanism consistent with these observations is proposed.
Chandler, W. David,Wang, Zhao,Lee, Donald G.
p. 1212 - 1221
(2005)
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PALLADIUM AND PHASE TRANSFER CATALYZED OXIDATION OF OLEFINS TO KETONES. SENSITIVITY OF THE REACTION TO THE NATURE OF THE PHASE TRANSFER AGENT.
Terminal olefins can be converted to ketones in good yields, and under mild conditions, using phase transfer catalysis; the quaternary ammonium salt governs the course of the react ion.
Januszkiewicz, Krzysztof,Alper, Howard
p. 5159 - 5162
(1983)
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Lochow,Miller
p. 3020
(1976)
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Production of renewable 1,3-pentadiene over LaPO4 via dehydration of 2,3-pentanediol derived from 2,3-pentanedione
1,3-Pentadiene plays an extremely important role in the production of polymers and fine chemicals. Herein, the LaPO4 catalyst exhibits excellent catalytic performance for the dehydration production of 1,3-pentadiene with 2,3-pentanediol, a C5 diol platform compound that can be easily obtained by hydrogenation of bio-based 2,3-pentanedione. The relationships of catalyst structure-acid/base properties-catalytic performance was established, and an acid-base synergy effect was disclosed for the on-purpose synthesis of 1,3-pentadiene. Thus, a balance between acid and base sites was required, and an optimized LaPO4 with acid/base ratio of 2.63 afforded a yield of 1,3-pentadiene as high as 61.5% at atmospheric pressure. Notably, the Br?nsted acid sites with weak or medium in LaPO4 catalyst can inhibit the occurrence of pinacol rearrangement, resulting in higher 1,3-pentadiene production. In addition, the investigation on reaction pathways demonstrated that the E2 mechanism was dominant in this dehydration reaction, accompanied by the assistance of E1 and E1cb.
Bai, Chenxi,Cui, Long,Dai, Quanquan,Feng, Ruilin,Liu, Shijun,Qi, Yanlong
(2022/02/07)

Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate-based Cobalt Catalyst
Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH4)3[CoMo6O18(OH)6], which is supported by a central cobalt (III) mononucleus and a ring-shaped pure inorganic ligand composed of six MoVIO6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non-toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.
Xie, Ya,Wang, Jingjing,Wang, Yunyun,Han, Sheng,Yu, Han
p. 4985 - 4989
(2021/10/12)

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.
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(2021/03/19)

Chemoselective and Site-Selective Reductions Catalyzed by a Supramolecular Host and a Pyridine-Borane Cofactor
Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.
Morimoto, Mariko,Cao, Wendy,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
supporting information
p. 2108 - 2114
(2021/02/06)

Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
Fossey-Jouenne, Aurélie,Jongkind, Ewald P. J.,Mayol, Ombeline,Paul, Caroline E.,Vergne-Vaxelaire, Carine,Zaparucha, Anne
(2021/12/23)

A Synergistic Magnetically Retrievable Inorganic-Organic Hybrid Metal Oxide Catalyst for Scalable Selective Oxidation of Alcohols to Aldehydes and Ketones
Herein, we report a synergistic silica coated magnetic Fe3O4 catalyst functionalized with nitrogen rich organic moieties and immobilized with cobalt metal ion (FNP-5) for selective oxidation of alcohols to aldehydes and ketones using tert-butyl hydroperoxide (TBHP) as oxidant. The catalyst was rigorously characterized via several techniques which delineate its core-shell structure, magnetic behavior, phase and crystal structure. The Co(III) acts as the active catalytic center for selective oxidation reaction. The control reactions revealed radical mechanistic pathway assisted by the synergism induced by the inorganic-organic hybrid nature of FNP-5. The other features of current protocol involve neat reaction conditions, high TOF values, scalability of product and low E-factor value (1.92). Moreover, FNP-5 could be effortlessly separated via an external magnet, displays recyclability over eight catalytic cycles and exhibits structural integrity even after rigorous use. Overall, these results manifest the understanding of synergistic architectures as sustainable surrogates for selective oxidation reactions.
Mittal, Rupali,Awasthi, Satish Kumar
p. 4799 - 4813
(2021/09/30)

Simultaneous Preparation of (S)-2-Aminobutane and d -Alanine or d -Homoalanine via Biocatalytic Transamination at High Substrate Concentration
(S)-2-Aminobutane, d-alanine, and d-homoalanine are important intermediates for the production of various active pharmaceutical ingredients and food additives. The preparation of these small chiral amine or amino acids with high water solubility still demands searching for efficient methods. In this work, we identified an ω-transaminase (ω-TA) from Sinirhodobacter hungdaonensis (ShdTA) that catalyzed the kinetic resolution of racemic 2-aminobutane at a concentration of 800 mM using pyruvate as the amino acceptor, leading to the simultaneous isolation of enantiopure (S)-2-aminobutane and d-alanine in 46% and 90% yield, respectively. In addition, (S)-2-aminobutane (98% ee) and d-homoalanine (99% ee) were isolated in 45% and 93% yield, respectively, in the kinetic resolution of racemic 2-aminobutane at a concentration of 400 mM coupled with deamination of l-threonine by threonine deaminase. We thus developed a biocatalytic process for the practical synthesis of these valuable small chiral amine and d-amino acids.
Li, Jianjiong,Wang, Yingang,Wu, Qiaqing,Yao, Peiyuan,Yu, Shanshan,Zhu, Dunming
supporting information

(2022/03/01)

Heterogeneous photocatalytic anaerobic oxidation of alcohols to ketones by Pt-mediated hole oxidation
We report a platinum nanocluster/graphitic carbon nitride (Pt/g-C3N4) composite solid catalyst with a photocatalytic anaerobic oxidation function for highly active and selective transformation of alcohols to ketones. The desirable products were successfully obtained in good to excellent yields from various functionalized alcohols at room temperature, including unactivated alcohols. Mechanistic studies indicated that the reaction could proceed through a Pt-mediated hole oxidation initiating an α-alcohol radical intermediate followed by a two-electron oxidation pathway. The merit of this strategy offers a general approach towards green and sustainable organic synthetic chemistry.
Sun, Danhui,Li, Peihe,Wang, Xia,Wang, Yingying,Wang, Jinghui,Wang, Yin,Lu, Ye,Duan, Limei,Sarina, Sarina,Zhu, Huaiyong,Liu, Jinghai
supporting information
p. 11847 - 11850
(2020/10/13)

Photochemical oxidation of benzylic primary and secondary alcohols utilizing air as the oxidant
A mild and green photochemical protocol for the oxidation of alcohols to aldehydes and ketones was developed. Utilizing thioxanthenone as the photocatalyst, molecular oxygen from air as the oxidant and cheap household lamps or sunlight as the light source, a variety of primary and secondary alcohols were converted into the corresponding aldehydes or ketones in low to excellent yields. The reaction mechanism was extensively studied.
Nikitas, Nikolaos F.,Tzaras, Dimitrios Ioannis,Triandafillidi, Ierasia,Kokotos, Christoforos G.
supporting information
p. 471 - 477
(2020/02/13)

Direct Catalytic Conversion of Ethanol to C5+ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability
Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd-promoted ZnO-ZrO2 catalyst. The sequence of reaction steps involved in the C5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross-aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. A yield of >70 percent to C5+ ketones was achieved over a 0.1 percent Pd-ZnO-ZrO2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.
Bathena, Tanmayi,Goulas, Konstantinos A.,Gray, Michel,Guo, Mond F.,Kovarik, Libor,Martinez, Abraham,Ramasamy, Karthikeyan K.,Subramaniam, Senthil,Zhang, Xiao
p. 14550 - 14557
(2020/07/08)

Efficient one-pot conversion of furfural into 2-methyltetrahydrofuran using non-precious metal catalysts
2-methyltetrahydrofuran, a biomass-derived chemical, is an important solvent with broad applications in organic chemistry. In this study, one-pot conversion of furfural into 2-methyltetrahydrofuran over non-precious metal catalysts was achieved by two-stage packing in a single reactor. The first stage converted furfural into 2-methylfuran over Co-based catalysts, and the second stage converted 2-methylfuran into 2-methyltetrahydrofuran over Ni-based catalysts. In order to reveal the reaction pathway and mechanism of this process, the hydrogenation reactions of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol were also carefully investigated. It is discovered that the conversion of furfural into 2-methylfuran could be catalyzed by Lewis acid sites, which was confirmed by a correlation between 2-methylfuran production rate and Lewis acid site density. Also, a mechanism on the direct conversion of furfural into 2-methylfuran without forming furfuryl alcohol as the intermediate is proposed. The experimental results of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol hydrogenation/hydrodeoxygenation over various catalysts provided valuable information on the future design of 2-methyltetrahydrofuran catalyst.
Jia, Xinxin,Li, Cuiqing,Liu, Ping,Song, Yongji,Sun, Luyang,Wang, Hong,Zhang, Chen,Zhang, Wei
(2020/04/29)

Donor-Flexible Bis(pyridylidene amide) Ligands for Highly Efficient Ruthenium-Catalyzed Olefin Oxidation
An exceptionally efficient ruthenium-based catalyst for olefin oxidation has been designed by exploiting N,N′-bis(pyridylidene)oxalamide (bisPYA) as a donor-flexible ligand. The dynamic donor ability of the bisPYA ligand, imparted by variable zwitterionic and neutral resonance structure contributions, paired with the redox activity of ruthenium provided catalytic activity for Lemieux–Johnson-type oxidative cleavage of olefins to efficiently prepare ketones and aldehydes. The ruthenium bisPYA complex significantly outperforms state-of-the-art systems and displays extraordinary catalytic activity in this oxidation, reaching turnover frequencies of 650 000 h?1 and turnover numbers of several millions.
Albrecht, Martin,Salzmann, Kevin,Segarra, Candela
supporting information
p. 8932 - 8936
(2020/04/22)

Synthesis method of primary amine hydrochloride
The invention discloses a synthesis method of primary amine hydrochloride. According to the synthesis method, in the presence of a gold complex, water and alkyne carry out catalytic hydrolysis to generate ketones, and then ketones and ammonium formate are catalyzed by a rhodium complex to generate primary amine. Compared with a conventional primary amine synthesis method, the synthesis method hasthe advantages that no alkali is added during the reaction process, no side product is generated, the atomic economy is good, the reaction conditions are mild, and the synthesis method has a wide prospect.
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(2019/03/09)

β-Amino Phosphine Mn Catalysts for 1,4-Transfer Hydrogenation of Chalcones and Allylic Alcohol Isomerization
Mn complexes with amino acid derived PN ligands were used in the catalytic transfer hydrogenation (TH) of ketone and chalcone substrates in 2-propanol with mild heating. Moreover, chalcones are reduced selectively to the saturated ketone at short times and can be fully converted to the alcohol when reactions are prolonged. The mechanism of chalcone reduction was briefly considered. Allylic alcohols are not reactive in 2-propanol, but quantitative isomerization occurs in toluene. Thus, we suspect that the allylic alcohols are dehydrogenated and the resulting ketone is formed through a direct 1,4-hydrogenation of the chalcone. Finally, several other related ligands that have been used in Mn-based TH reactions were explored to test the viability of ligand design in favoring chemoselectivity. The β-amino phosphine ligands proved most effective in this regard.
Vigneswaran, Vipulan,MacMillan, Samantha N.,Lacy, David C.
supporting information
p. 4387 - 4391
(2019/11/14)

Efficient synthesis of enantiopure amines from alcohols using resting: E. coli cells and ammonia
α-Chiral amines are pivotal building blocks for chemical manufacturing. Stereoselective amination of alcohols is receiving increased interest due to its higher atom-efficiency and overall improved environmental footprint compared with other chemocatalytic and biocatalytic methods. We previously developed a hydrogen-borrowing amination by combining an alcohol dehydrogenase (ADH) with an amine dehydrogenase (AmDH) in vitro. Herein, we implemented the ADH-AmDH bioamination in resting Escherichia coli cells for the first time. Different genetic constructs were created and tested in order to obtain balanced expression levels of the dehydrogenase enzymes in E. coli. Using the optimized constructs, the influence of several parameters towards the productivity of the system were investigated such as the intracellular NAD+/NADH redox balance, the cell loading, the survival rate of recombinant E. coli cells, the possible toxicity of the components of the reaction at different concentrations and the influence of different substrates and cosolvents. In particular, the cofactor redox-balance for the bioamination was maintained by the addition of moderate and precise amounts of glucose. Higher concentrations of certain amine products resulted in toxicity and cell death, which could be alleviated by the addition of a co-solvent. Notably, amine formation was consistent using several independently grown E. coli batches. The optimized E. coli/ADH-AmDH strains produced enantiopure amines from the alcohols with up to 80% conversion and a molar productivity up to 15 mM. Practical applicability was demonstrated in a gram-scale biotransformation. In summary, the present E. coli-ADH-AmDH system represents an important advancement towards the development of 'green', efficient and selective biocatalytic processes for the amination of alcohols.
Houwman, Joseline A.,Knaus, Tanja,Costa, Magda,Mutti, Francesco G.
supporting information
p. 3846 - 3857
(2019/07/31)

Methanol as hydrogen source: Chemoselective transfer hydrogenation of α,β-unsaturated ketones with a rhodacycle
Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes highly chemoselective hydrogenation of α,β-unsaturated ketones with methanol as the hydrogen source. A wide variety of chalcones, styryl methyl ketones and vinyl methyl ketones, including sterically demanding ones, were reduced to the saturated ketones in refluxing methanol in a short reaction time, with no need for inter gas protection, and no reduction of the carbonyl moieties was observed. The catalysis described provides a practically easy and operationally safe method for the reduction of olefinic bonds in α,β-unsaturated ketone compounds.
Aboo, Ahmed H.,Begum, Robina,Zhao, Liangliang,Farooqi, Zahoor H.,Xiao, Jianliang
p. 1795 - 1799
(2019/11/11)

Efficient Palladium(0) supported on reduced graphene oxide for selective oxidation of olefins using graphene oxide as a ‘solid weak acid’
Selective oxidation of olefin derivatives to ketones has made innovative development over palladium(0) supported on reduced graphene oxide. Compared to traditional Wacker oxidation, the novel method offers an economical and environment-friendly option by using graphene oxide (GO) as a ‘solid weak acid’ instead of classical homogeneous catalysts like H2SO4 and CF3COOH. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy images of Pd0/RGO showed that the nanoscaled Pd particles generated at the flake structure of reduced graphene oxide. Under optimized condition, up to 44 kinds of ketones with different structures can be prepared with excellent yields.
Gao, Xi,Zhou, Jianhao,Peng, Xinhua
p. 73 - 78
(2019/02/06)

Half-sandwich ruthenium-based versatile catalyst for both alcohol oxidation and catalytic hydrogenation of carbonyl compounds in aqueous media
A series of half-sandwich ruthenium-based catalysts for both alcohol oxidation and carbonyl compounds hydrogenation have been synthesized through metal-induced C–H bond activation based on benzothiazole ligands. The neutral ruthenium complexes 1–4 were fully characterized by UV–vis, NMR, IR, and elemental analysis. Molecular structures of complexes 1 and 3 were further confirmed by X-ray diffraction analysis. All complexes exhibited high activity for the catalytic oxidation of a variety of alcohols with tBuOOH as oxidants to give carbonyl compounds with high yields in water. Moreover, these half-sandwich complexes also showed high efficiency for the catalytic hydrogenation of carbonyl compounds in a methanol–water mixture. The catalyst could be reused for at least five cycles without any loss of activity. The catalytic system also worked well for various kinds of substrates with either electron-donating or electron-withdrawing groups.
Qiao, Xin-Chao,Qiu, Dan-Chen,Lin, Nan,Zhu, Jing-Wei,Deng, Wei,Yao, Zi-Jian
(2019/03/17)

Synergistic hydrogen atom transfer with the active role of solvent: Preferred one-step aerobic oxidation of cyclohexane to adipic acid by N-hydroxyphthalimide
In this work, we developed an one-step aerobic oxidation of cyclohexane to prepare adipic acid, catalyzed by N-hydroxyphthalimide (NHPI) under promoter- and metal-free conditions. A significant beneficial solvent effect for synergistic reaction is observed with varying polarity and hydrogen-bonding strength: detailed study reveals that the solvent environments manipulate catalytic activity and adipic acid selectivity. Cyclic voltammetry measurements and UV–visible spectra of the NHPI catalyst are examined in various solvent environments to understand the active role of solvent in influencing the catalytic-site structure (>NOH) of the molecule. Analysis of the UV–visible spectra reveals that these differences can be rationalized by considering hydrogen-bonding with solvent molecules, which modifies the catalytic-site structure. This observation is in agreement with cyclic voltammetry results: the different reversibility of the catalytic-site (>NOH/>NO[rad]) wave shows that the catalytic activity of NHPI is related to the formation of hydrogen bonds with the active participation of solvents. Computational studies presented herein have furnished mechanistic insights into the effect of solvent environments. Specifically, we present the structures, dissociation energies, and reaction barriers from DFT studies of the reactants and reaction intermediates involved in the two types of H-abstraction on >NO[rad] catalytic-sites for the rate-determining step. The results of modeling the solvent effects using the PCM continuum solvent method predict that the resulting reaction barrier of the rate-controlling H-abstraction for cyclohexane and cyclohexanone is modified significantly: the transition state barrier of H-abstraction for cyclohexane decreases from 22.36 (in benzene) to 20.78 kcal?mol?1 (in acetonitrile); the α-H-abstraction barrier for cyclohexanone decreases from 21.45 to 20.53 kcal?mol?1. The active participation of solvent molecule results in a strong interaction between pre-reaction complex (PINO???H???C NO[rad] catalytic-sites at the transition state. The lower calculated barriers of H-abstraction for cyclohexanone oxidation approximate more closely the experimental results of the higher adipic acid selectivity. Our work provides a dimension of sustainable chemistry for the metal-free preparation of adipic acid: a conversion of 27% with 79% adipic acid selectivity is achieved over use of NHPI catalysts in CH3CN solvent.
Liang, Futong,Zhong, Wenzhou,Xiang, Liping,Mao, Liqiu,Xu, Qiong,Kirk, Steven Robert,Yin, Dulin
p. 256 - 269
(2019/09/30)

Enantiocomplementary decarboxylative hydroxylation combining photocatalysis and whole-cell biocatalysis in a one-pot cascade process
Designing a green, highly efficient and stereoselective catalytic system to generate valuable enantioenriched products is a long-standing goal in green chemistry. Here, we report a one-pot cascade combining photocatalysts with (R)- or (S)-selective ketoreductases for the decarboxylative carbonylation of carboxylic acids and the subsequent bioreduction to generate valuable chiral alcohols. Using this approach, various chiral alcohols with complementary (R)- or (S)-configurations were prepared with good yields (up to 93%) and excellent stereoselectivity (up to 99% ee). Such a photochemo-enzymatic one-pot whole-cell process combines the advantages of both photocatalysts and enzyme catalysts and provides a mild, green, metal-free and highly stereoselective alternative in asymmetric decarboxylative hydroxylation reactions.
Xu, Jian,Arkin, Mamatjan,Peng, Yongzhen,Xu, Weihua,Yu, Huilei,Lin, Xianfu,Wu, Qi
supporting information
p. 1907 - 1911
(2019/04/27)

Deracemization of Racemic Amines to Enantiopure (R)- and (S)-amines by Biocatalytic Cascade Employing ω-Transaminase and Amine Dehydrogenase
A one-pot deracemization strategy for α-chiral amines is reported involving an enantioselective deamination to the corresponding ketone followed by a stereoselective amination by enantiocomplementary biocatalysts. Notably, this cascade employing a ω-transaminase and amine dehydrogenase enabled the access to both (R)-and (S)-amine products, just by controlling the directions of the reactions catalyzed by them. A wide range of (R)-and (S)-amines was obtained with excellent conversions (>80 %) and enantiomeric excess (>99 % ee). Finally, preparative scale syntheses led to obtain enantiopure (R)- and (S)-13 with the isolated yields of 53 and 75 %, respectively.
Yoon, Sanghan,Patil, Mahesh D.,Sarak, Sharad,Jeon, Hyunwoo,Kim, Geon-Hee,Khobragade, Taresh P.,Sung, Sihyong,Yun, Hyungdon
p. 1898 - 1902
(2019/02/27)

Rational Design of a Metallocatalytic Cavitand for Regioselective Hydration of Specific Alkynes
The synthesis of a functionalized supramolecular cavitand with inwardly oriented AuI and P=O moieties was explored, including its catalytic proclivity in the selective hydration of internal alkynes. The cavitand works as a supramolecular flask device: AuI coordinates to the triple bond, the P=O moiety connects with a H2O molecule, and the cavity favors folding of a single alkynyl side chain. Several tests of different substrate patterns indicated that the cavity was substrate specific, similar to enzymatic catalysis.
Endo, Naoki,Inoue, Mami,Iwasawa, Tetsuo
supporting information
p. 1136 - 1140
(2018/03/13)

Promotional synergistic effect of Sn doping into a novel bimetallic Sn-W oxides/graphene catalyst for selective oxidation of alcohols using aqueous H2O2 without additives
A series of novel catalysts with bimetallic Sn-W oxides uniformly dispersed on reduced graphene oxide (denoted as Sn-W/RGO) were successfully prepared via a conventional one-pot hydrothermal method. Interestingly, it was found that the introduction of Sn could significantly improve the catalytic activities compared with single WO3/graphene catalyst for selective oxidation of alcohols using H2O2 without organic solvents and additives. Subsequently, the catalysts were characterized by FT-IR, XRD, Raman, FESEM, EDS, HRTEM, XPS and N2 adsorption-desorption to investigate the promotional synergistic effect of Sn among catalyst structure, surface properties and catalytic performance. The results revealed that the incorporation of Sn had induced the formation of hexagonal WO3 with dominant exposed (001) and (200) planes, meanwhile, doping Sn could dramatically increase the specific surface area, change the structural properties and enhance the interactions between Sn-W oxides and graphene, which were beneficial to the improvement of catalytic performance. Additionally, reaction parameters (temperature, time, oxidant dosage and catalyst amount) were also explored. Both aryl and alkyl alcohols exhibited high conversion and selectivity to corresponding target products over the catalyst. And delightedly, the robust catalyst could be reused for five times without significant loss in catalytic efficiency. This work demonstrates the promotional synergistic effect of Sn in a novel Sn-doped WO3/RGO catalyst and makes it a promising candidate in green oxidation of alcohols under mild reaction conditions.
Xu, Cai,Zhang, Lingling,An, Yu,Wang, Xiaozhong,Xu, Gang,Chen, Yingqi,Dai, Liyan
p. 26 - 33
(2018/11/23)

Iron(III) Complexes with Cross-Bridged Cyclams: Synthesis and Use in Alcohol and Water Oxidation Catalysis
A class of iron(III) complexes containing diversely substituted cross-bridged cyclams (1-R,R′: 1-Me,Me, 1-Me,Et, 1-Et,Et, 1-Me,Bn, 1-Bn,Bn) has been prepared and characterized. (1-R,R′) complexes catalyze the oxidation of alcohols to ketones in green cond
Annunziata, Alfonso,Esposito, Roberto,Gatto, Giordano,Cucciolito, Maria Elena,Tuzi, Angela,Macchioni, Alceo,Ruffo, Francesco
p. 3304 - 3311
(2018/07/31)

Biocatalytic Racemization Employing TeSADH: Substrate Scope and Organic Solvent Compatibility for Dynamic Kinetic Resolution
Racemization in combination with a kinetic resolution is the base for a dynamic kinetic resolution (DKR). Biocatalytic racemization was successfully performed for a broad scope of sec-alcohols by employing a single alcohol dehydrogenase (ADH) variant from Thermoanaerobacter pseudoethanolicus (formerly T. ethanolicus; TeSADH W110A I86A C295A). The catalyst employed as a lyophilized whole cell preparation or cell free extract, which tolerated various non-water miscible organic solvents under micro-aqueous or two-phase conditions, whereby cyclohexane and n-hexane suited best. Various concepts for combining the enzymatic racemization with an enzymatic kinetic resolution to achieve overall a bis-enzymatic DKR were evaluated. A proof of concept showed a successful DKR with racemization in aqueous phase combined with acylation in the organic phase.
Pop?oński, Jaros?aw,Reiter, Tamara,Kroutil, Wolfgang
p. 763 - 768
(2018/02/27)

Design and Assembly of a Chiral Metallosalen-Based Octahedral Coordination Cage for Supramolecular Asymmetric Catalysis
Supramolecular containers featuring both high catalytic activity and high enantioselectivity represent a design challenge of practical importance. Herein, it is demonstrated that a chiral octahedral coordination cage can be constructed by using twelve enantiopure Mn(salen)-derived dicarboxylic acids as linear linkers and six Zn4-p-tert-butylsulfonylcalix[4]arene clusters as tetravalent four-connected vertices. The porous cage features a large hydrophobic cavity (≈3944 ?3) decorated with catalytically active metallosalen species and is shown to be an efficient and recyclable asymmetric catalyst for the oxidative kinetic resolution of racemic secondary alcohols and the epoxidation of olefins with up to >99 % enantiomeric excess. The cage architecture not only prevents intermolecular deactivation and stabilizes the Mn(salen) catalysts but also encapsulates substrates and concentrates reactants in the cavity, resulting in enhanced reactivity and enantioselectivity relative to the free metallosalen catalyst.
Tan, Chunxia,Jiao, Jingjing,Li, Zijian,Liu, Yan,Han, Xing,Cui, Yong
supporting information
p. 2085 - 2090
(2018/02/06)

Hydrogenation of Ketones and Esters Catalyzed by Pd/C?SiO2
Hydrogenation of unsaturated ketones and esters with molecular hydrogen on the 5%Pd/C?SiO2 heterogeneous catalyst has been studied. The reaction direction and yield are determined by the starting compounds structure. Hydrogenation of unsaturated ketones containing phenyl group at the double carbon–carbon atom is accompanied by the reduction of the ketone group into the alcohol one. Hydrogenation of unsaturated esters is accompanied by transesterification.
Akchurin,Baibulatov,Dokichev
p. 195 - 198
(2018/03/26)

Reductive Amination by Photoredox Catalysis and Polarity-Matched Hydrogen Atom Transfer
The excitation of a RuII photosensitizer in the presence of ascorbic acid leads to the reduction of iminium ions to electron-rich α-aminoalkyl radical intermediates, which are rapidly converted into reductive amination products by thiol-mediated hydrogen atom transfer (HAT). As a result, the reductive amination of carbonyl compounds with amines by photoredox catalysis proceeds in good to excellent yields and with broad substrate scope and good functional group tolerance. The three key features of this work are 1) the rapid interception of electron-rich α-aminoalkyl radical intermediates by polarity-matched HAT in a photoredox reaction, 2) the method of reductive amination by photoredox catalysis itself, and 3) the application of this new method for temporally and spatially controlled reactions on a solid support, as demonstrated by the attachment of a fluorescent dye on an activated cellulose support by photoredox-catalyzed reductive amination.
Guo, Xingwei,Wenger, Oliver S.
supporting information
p. 2469 - 2473
(2018/01/27)

Synthesis and characterization of some new half-sandwich ruthenium(II) complexes with bidentate N,N′-ligands and their application in alcohol oxidation
A series of eight new (η6-arene)ruthenium(II) complexes were prepared by the reaction of pyridyl-imine ligands and the ruthenium(II) precursors of the general formula [(η6-arene)Ru(μ-Cl)Cl]2, where arene = p-cymene (1) and C6H6(2), to form the complexes [(η6-arene)RuCl(C5H4N-2-CH[dbnd]N-Ar)]PF6(where Ar = 2,4,6-trimethylphenyl (a), 2,4-dimethylphenyl (b), 2-methoxyphenyl (c), 2,6-diisopropylphenyl (d)).These complexes were characterized using 1H NMR, 13C NMR, 31P NMR, IR, UV–Vis, HRMS, and TGA. The molecular structures for the complexes 1a,1d, 2a and 2d were determined by single crystal crystallography, revealing a pseudo-octahedral piano stool geometry. In this arrangement, the ruthenium metal is coordinated to the arene ligand at the apex of the stool with one chloride and the N,N-ligand as the base. These complexes were applied as catalysts in the oxidation of cyclic, aliphatic and aromatic alcohols with NaIO4as oxidant and the complexes showed good conversions and yields to the corresponding carbonyl products.
Gichumbi, Joel M.,Friedrich, Holger B.,Omondi, Bernard
p. 55 - 63
(2016/12/09)

A TEMPO-like nitroxide combined with an alkyl-substituted pyridine: An efficient catalytic system for the selective oxidation of alcohols with iodine
An efficient method for the oxidation of alcohols to aldehydes or ketones in a two-phase CH2Cl2/NaHCO3 (aq.) system, using iodine and catalytic amounts of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl and 2,4,6-trimethylpyridine, was developed. The performance of the method was demonstrated by the selective oxidation of 37 variously substituted alcohols in ≥90% yield, including the gram-scale synthesis of the important chemical 2,5-diformylfuran from biomass-derived 5-hydroxylmethylfurfural.
Kashparova, Vera P.,Klushin, Victor A.,Zhukova, Irina Yu.,Kashparov, Igor S.,Chernysheva, Daria V.,Il'chibaeva, Irina B.,Smirnova, Nina V.,Kagan, Efim Sh.,Chernyshev, Victor M.
supporting information
p. 3517 - 3521
(2017/10/05)

Synthesis of an oligomer ruthenium complex and its catalysis in the oxidation of alcohols
A ligand with both a terpyridine and a pyridine-2,6-dicarboxylate group (abbreviated as terpy-pydic) was designed and synthesized. This ligand reacted with [Ru(p-cymene)Cl2]2 to afford a novel oligomer ruthenium complex named as oligomer-Ru(terpy)(pydic) which was characterized thoroughly. Under the catalysis of this oligomer ruthenium complex, different sorts of secondary alcohols were oxidized to the corresponding kenones by the oxidant tert-butyl hydroperoxide. Besides, this catalyst can be readily recovered and recycled several times without a large loss of its efficiency.
Zhang, Yuecheng,Huo, Wenge,Zhang, Hong-Yu,Zhao, Jiquan
p. 47261 - 47270
(2017/10/19)

Complexes of (η5-Cp*)Ir(iii) with 1-benzyl-3-phenylthio/selenomethyl-1,3-dihydrobenzoimidazole-2-thione/selenone: catalyst for oxidation and 1,2-substituted benzimidazole synthesis
The treatment of 1-benzyl-3-phenylthio/selenomethyl-1,3-dihydrobenzoimidazole-2-thione/selenone [L1-L4] with [(η5-Cp*)IrCl(μ-Cl)]2 at 25 °C followed by NH4PF6 results in [(η5-Cp*)Ir(L)Cl][PF6/su
Sharma, Alpesh K.,Joshi, Hemant,Bhaskar, Renu,Singh, Ajai K.
p. 2228 - 2237
(2017/02/23)

Method for preparing aldehyde ketone by efficiently catalyzing molecular oxygen to oxidize alcohol by taking hydrotalcite-like material as catalyst
The invention belongs to the technical field of liquid-phase catalytic oxidation and provides a method for preparing aldehyde ketone by efficiently catalyzing molecular oxygen to oxidize alcohol by taking a hydrotalcite-like material as a catalyst. The catalyst can be expressed as A-NixM-LDHs (A=OH, CO3, CH3COO and PO4; M is Ga or In; the ratio of Ni to M is (2-4) to 1). The method is characterized by preparing aldoketones compounds by carrying out aerobic oxidation reaction on alcohol under mild condition without adding additives in the presence of the catalyst. The hydrotalcite-like material can be synthesized in quantity and can be recycled; the method has the advantages of high selectivity and yield of aldehyde ketone, mild reaction condition, low cost and easiness in realizing industrialization.
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Paragraph 0036; 0037; 0038; 0039; 0042

(2017/09/29)

Method of preparing 2-pentanone from ethanol
The invention relates to a method of preparing 2-pentanone from ethanol. According to the method, CeO2 is taken as the catalyst, in a fixed bed reactor, in an inert gas atmosphere, ethanol is taken as the raw material, reactions are carried out at a temperature of 200 to 600 DEG C under a normal pressure; the liquid hourly space velocity (LHSV) of the reactions is 0.1-6.0 gh, and the gas space velocity of the reactions is 2000 to 8000 mL.gh. The method can efficiently convert cheap ethanol into 2-pentanone in one step. The ethanol conversion rate can reach 92.8%. The selectivity of 2-pentanone is 36.8%. Moreover, the used catalyst raw materials are cheap and easily-available, the preparation method is simple, a normal pressure reaction technology is adopted, the operation is easy, and the method can be applied to the industrial application.
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Paragraph 0031; 0033; 0047

(2017/04/27)

A ethanol for one-step synthesis of 2 - pentanone (by machine translation)
The invention relates to a one-step synthesis of ethanol for 2 - pentanone, the method specific process is in ethanol as the raw material, in the reactor, metal-doped cerium oxide catalyst, the inert gas as a carrier gas, the reaction temperature is 250 - 550 °C, obtained by the reaction of 2 - pentanone. The reaction liquid hourly space velocity is 0.1 - 5.0h-1 , Reaction gas hourly space velocity is 1500 - 6000 ml ·gCat -1 h-1 . The process can be a rich source of ethanol is the high-efficient transformation step 2 - pentanone, ethanol conversion rate can be up to 94.8%, the selectivity of 2 - pentanone to 41.8%, and the process atmosphere reaction process and easy operation, the catalyst preparation method is simple and convenient, and good catalytic effect, and stability in the long run, with potential industrial application prospect. (by machine translation)
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Paragraph 0028; 0029; 0030; 0031; 0032; 0033; 0034; 0035-004

(2017/08/27)

Mononuclear Ruthenium and Osmium Complexes with a Bicyclic Guanidinate Ligand: Synthesis and Catalytic Behavior in Olefin Isomerization Processes
The preparation of the first mononuclear RuII, RuIV, and OsII complexes containing the anion of the bicyclic guanidine 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (Hhpp) as a chelating ligand, namely [RuX{κ2-(N,N′)-hpp}(η6-arene)] [arene = p-cymene, X = Cl (2a), Br (2b), I (2c); arene = C6Me6, X = Cl (7)], [RuCl{κ2-(N,N′)-hpp}(η3:η3-C10H16)] (9; C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl), and [OsCl{κ2-(N,N′)-hpp}(η6-p-cymene)] (11), is described. Compounds 2a–c, 7, 9, and 11 have been fully characterized by elemental analysis, HRMS, IR and NMR spectroscopy. In addition, the structure of 2a has been unequivocally confirmed by single-crystal X-ray diffraction methods. The catalytic behavior of these metal guanidinate complexes in the base-free redox isomerization of allylic alcohols is explored, with the ruthenium(IV) derivative 9 showing the best performance (TOF up to 5940 h–1). All of the synthesized complexes have also proven to be active in the isomerization of the allylbenzene estragole into the industrially relevant 1-propenylbenzene anethole, with a trans selectivity of up to 95 %.
Gámez-Rivera, Sebastián A.,Francos, Javier,Borge, Javier,Cadierno, Victorio
p. 4138 - 4146
(2017/09/28)

Selective Photooxidation Reactions using Water-Soluble Anthraquinone Photocatalysts
The aerobic organocatalytic oxidation of alcohols was achieved by using water-soluble sodium anthraquinone sulfonate. Under visible-light activation, this catalyst mediated the aerobic oxidation of alcohols to aldehydes and ketones. The photo-oxyfunctionalization of alkanes was also possible under these conditions.
Zhang, Wuyuan,Gacs, Jen?,Arends, Isabel W. C. E.,Hollmann, Frank
p. 3821 - 3826
(2017/09/13)

Two-Enzyme Hydrogen-Borrowing Amination of Alcohols Enabled by a Cofactor-Switched Alcohol Dehydrogenase
The NADPH-dependent secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (TeSADH), displaying broad substrate specificity and low enantioselectivity, was engineered to accept NADH as a cofactor. The engineered TeSADH showed a >10 000-fold switch from NADPH towards NADH compared to the wildtype enzyme. This TeSADH variant was applied to a biocatalytic hydrogen-borrowing system that employed catalytic amounts of NAD+, ammonia, and an amine dehydrogenase, which thereby enabled the conversion a range of alcohols into chiral amines.
Thompson, Matthew P.,Turner, Nicholas J.
p. 3833 - 3836
(2017/09/25)

Methods to produce fuels
The present disclosure generally relates to the catalytic conversion of alcohols into hydrocarbon ketones suitable for use as fuels. More specifically, the present disclosure relates to the catalytic conversion of a mixture of isopropanol-butanol-ethanol (IBE) or acetone-butanol-ethanol (ABE), into ketones suitable for use as fuels. The ABE or IBE mixtures may be obtained from the fermentation of biomass or sugars.
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Page/Page column 54; 55; 56

(2018/02/28)

Comparison of phosphide catalysts prepared by temperature-programmed reduction and liquid-phase methods in the hydrodeoxygenation of 2-methylfuran
Two types of Ni2P/SiO2 were prepared by different methods, a conventional method involving temperature-programmed reduction (TPR) and a liquid-phase synthesis (LP). Both methods resulted in phase-pure materials with the Ni2P hexagonal phase, but the sample prepared by TPR had lower particle size (7 nm) than the sample prepared by LP synthesis (25 nm). The samples were tested in the gas-phase hydrodeoxygenation of 2-methylfuran (2-MF) in H2 at 0.5 MPa and 250–450 °C, and it was found that the Ni2P/SiO2-TPR gave higher conversions and turnover frequencies than the Ni2P/SiO2-LP. It was conjectured that the difference in activity was due to the higher phosphorus content of the sample prepared by TPR, and this was confirmed by measurements of the P/Ni ratio by x-ray photoelectron spectroscopy. The main products formed by the two catalysts were 2-pentanone and n-pentane and small amounts of 1-pentanol and 2-pentanol. Contact time measurements on the Ni2P/SiO2-TPR sample indicated that 2-pentanone was a primary product, the pentanols were intermediary compounds, and the n-pentane was a final product. Kinetic measurements on the Ni2P/SiO2-LP revealed orders of 0.6 for the 2-MF and 0.5 for H2, consistent with adsorption of both reactants on the catalyst and a surface reaction between the adsorbed species. TPR was also employed to prepare a Cu3P/SiO2 sample. Although a phase-pure material was formed, the substance showed very low activity for the HDO of 2-MF.
Zhang, Jianwen,Matsubara, Kazuki,Yun, Gwang-Nam,Zheng, Huidong,Takagaki, Atsushi,Kikuchi, Ryuji,Oyama, S. Ted
p. 39 - 46
(2017/10/05)

In vitro biocatalytic pathway design: Orthogonal network for the quantitative and stereospecific amination of alcohols
The direct and efficient conversion of alcohols into amines is a pivotal transformation in chemistry. Here, we present an artificial, oxidation-reduction, biocatalytic network that employs five enzymes (alcohol dehydrogenase, NADP-oxidase, catalase, amine dehydrogenase and formate dehydrogenase) in two concurrent and orthogonal cycles. The NADP-dependent oxidative cycle converts a diverse range of aromatic and aliphatic alcohol substrates to the carbonyl compound intermediates, whereas the NAD-dependent reductive aminating cycle generates the related amine products with >99% enantiomeric excess (R) and up to >99% conversion. The elevated conversions stem from the favorable thermodynamic equilibrium (K′eq = 1.88 × 1042 and 1.48 × 1041 for the amination of primary and secondary alcohols, respectively). This biocatalytic network possesses elevated atom efficiency, since the reaction buffer (ammonium formate) is both the aminating agent and the source of reducing equivalents. Additionally, only dioxygen is needed, whereas water and carbonate are the by-products. For the oxidative step, we have employed three variants of the NADP-dependent alcohol dehydrogenase from Thermoanaerobacter ethanolicus and we have elucidated the origin of the stereoselective properties of these variants with the aid of in silico computational models.
Knaus, Tanja,Cariati, Luca,Masman, Marcelo F,Mutti, Francesco G.
p. 8313 - 8325
(2017/10/19)

Selective Hydrogenation of 2-Methylfuran and 2,5-Dimethylfuran over Atomic Layer Deposited Platinum Catalysts on Multiwalled Carbon Nanotube and Alumina Supports
2-Methylfuran (2MF) and 2,5-dimethylfuran (DMF) were hydrogenated in the vapor phase to the corresponding tetrahydrofurans, linear 2-ketones, and alcohols over Pt nanoparticles supported on multiwalled carbon nanotubes (MWCNTs) and alumina by atomic layer deposition. The hydrogenation behavior of sub-nanometer Pt deposited on alumina was influenced by the acidity of the support. Relative to a commercial Pt/C catalyst, the Pt/MWCNT catalyst was found to contain similarly sized Pt nanoparticles that display a broader size distribution and significantly more n-alkanes than oxygenates during hydrogenation of these alkyl-substituted furans.
Kang, Jungshik,Liang, Xinhua,Guliants, Vadim V.
p. 282 - 286
(2017/02/05)

ABE Condensation over Monometallic Catalysts: Catalyst Characterization and Kinetics
Herein, we present work on the catalyst development and the kinetics of acetone-butanol-ethanol (ABE) condensation. After examining multiple combinations of metal and basic catalysts reported in the literature, Cu supported on calcined hydrotalcites (HT) was found to be the optimal catalyst for the ABE condensation. This catalyst gave a six-fold increase in reaction rates over previously reported catalysts. Kinetic analysis of the reaction over CuHT and HT revealed that the rate-determining step is the C?H bond activation of alkoxides that are formed from alcohols on the Cu surface. This step is followed by the addition of the resulting aldehydes to an acetone enolate formed by deprotonation of the acetone over basic sites on the HT surface. The presence of alcohols reduces aldol condensation rates, as a result of the coverage of catalytic sites by alkoxides.
Goulas, Konstantinos A.,Gunbas, Gorkem,Dietrich, Paul J.,Sreekumar, Sanil,Grippo, Adam,Chen, Justin P.,Gokhale, Amit A.,Toste, F. Dean
p. 677 - 684
(2017/02/26)

Direct Au-Ni/Al2O3 catalysed cross-condensation of ethanol with isopropanol into pentanol-2
Ethanol and isopropanol cross-condensation 0.2Au-0.06Ni/γ-Al2O3 catalyst have been developed based on the synergetic effect of gold and nickel in many reactions. A cross-condensation reaction results in the formation of pentanol-2 and pentanon-2 in high yields in the absence of any alkali or sacrificial agents (e.g., hydrogen acceptors or hydrogen donors). In this study, heterogeneous Au-Ni/Al2O3 catalysts were used in this type of reaction for the first time. The catalyst developed in this study is also effective for the self-condensation of ethanol, providing 85% selectivity of linear α-alcohols at 63.5% ethanol conversion. Structural investigations show that the morphological peculiarities and charge state of gold may produce the different activities of mono- and bimetallic Au- and Ni-containing catalysts.
Chistyakov,Zharova,Nikolaev,Tsodikov
(2016/11/11)