141-78-6Relevant articles and documents
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Lane et al.
, p. 6492 (1968)
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ESI-MS Insights into Acceptorless Dehydrogenative Coupling of Alcohols
Vicent, Cristian,Gusev, Dmitry G.
, p. 3301 - 3309 (2016)
Acceptorless dehydrogenative coupling (ADC) reactions catalyzed by a series of Ru and Os complexes were studied by ESI-MS. Important ethoxo, 1-ethoxyethanolate, and hydride intermediates were intercepted in the ADC of ethanol to ethyl acetate. Collision-induced dissociation (CID) experiments were applied as a structure elucidation tool and as a probe of the propensity of the reaction intermediates to evolve acetaldehyde, ethyl acetate, and H2, relevant to the catalytic cycle. The key mechanistic step producing ethyl acetate from the 1-ethoxyethanolate intermediates was documented. Energy-dependent CID experiments demonstrated the importance of a vacant coordination site for efficient production of ethyl acetate. The versatility and potential broad applicability of ESI-MS and its tandem version with CID was further illustrated for the ADC reaction of alcohols with amines, affording amides. A mechanism related to that found for the ester synthesis is plausible, with the key step involving formation of a hemiaminaloxide intermediate.
Total oxidation of ethanol over Au/Ce0.5Zr0.5O2 cordierite monolithic catalysts
Topka, Pavel,Klementová, Mariana
, p. 130 - 137 (2016)
The aim of this work was to propose the methods for gold introduction during the preparation of monolithic catalysts and to investigate their effect on catalyst properties. Two types of catalysts were prepared: (i) monoliths washcoated with gold/ceria-zirconia powder, and (ii) gold deposited on the monoliths washcoated with ceria-zirconia powder. An important part of the work was the characterization of the catalysts, in particular Au particle size and redox properties. Catalytic performance and selectivity were evaluated using ethanol gas-phase oxidation. It was shown that the enhanced reducibility of the catalysts with higher Au dispersion leads to improved catalytic performance.
A dinuclear strontium(II) complex as substrate-selective catalyst of ester cleavage
Cacciapaglia,Di Stefano,Mandolini
, p. 5926 - 5928 (2001)
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Iodide-induced differential control of metal ion reduction rates: synthesis of terraced palladium-copper nanoparticles with dilute bimetallic surfaces
King, Melissa E.,Personick, Michelle L.
, p. 22179 - 22188 (2018)
Metal nanoparticles possessing a high density of atomic steps and edge sites provide an increased population of undercoordinated surface atoms, which can enhance the catalytic activity of these materials compared to low-index faceted or bulk materials. Simply increasing reactivity, however, can lead to a concurrent increase in undesirable, non-selective side products. The incorporation of a second metal at these reactive stepped features provides an ideal avenue for finely attenuating reactivity to increase selectivity. A major challenge in synthesizing bimetallic nanomaterials with tunable surface features that are desirable for fundamental catalytic studies is a need to bridge differences in precursor reduction potentials and metal lattice parameters in structures containing both a noble metal and a non-noble metal. We report the use of low micromolar concentrations of iodide ions as a means of differentially controlling the relative reduction rates of a noble metal (palladium) and a non-noble metal (copper). The iodide in this system increases the rate of reduction of palladium ions while concurrently slowing the rate of copper ion reduction, thus providing a degree of control that is not achievable using most other reported means of tuning metal ion reduction rate. This differential control of metal ion reduction afforded by iodide ions enables access to nanoparticle growth conditions in which control of palladium nanoparticle growth by copper underpotential deposition becomes possible, leading to the generation of unique terraced bimetallic particles. Because of their bimetallic surface composition, these terraced nanoparticles exhibit increased selectivity to acetaldehyde in gas phase ethanol oxidation.
Radical-Induced Reductive Deamination of Amino Acid Esters
Barton, Derek H. R.,Bringmann, Gerhard,Motherwell, Wiliam B.
, p. 68 - 70 (1980)
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Acetic acid hydrogenation to ethanol over supported Pt-Sn catalyst: Effect of Bronsted acidity on product selectivity
Rakshit, Pranab Kumar,Voolapalli, Ravi Kumar,Upadhyayula, Sreedevi
, p. 78 - 90 (2018)
Gas phase hydrogenation of acetic acid was investigated over a series of SiO2-Al2O3 supported platinum-tin (Pt-Sn) catalysts. The active metals were impregnated over the support using incipient wetness technique and the resulting catalyst samples were characterized by Transmission electron microscopy, Hydrogen pulse chemisorption, BET surface area analyzer, Powder X-Ray diffraction, NH3-Temperature programmed desorption and H2-Temperature programmed reduction methods. Acetic acid hydrogenation reaction was carried out in an isothermal fixed bed catalyst testing unit. The results revealed that bimetallic Pt-Sn catalyst forms Pt-Sn alloy upon reduction which favors acetic acid hydrogenation to ethanol compared to competing side product CH4. The magnitude of Pt-Sn alloy formed per unit mass of catalyst depends upon the Pt/ Sn molar ratio in the calcined catalyst sample. 3 wt% Pt- 3 wt% Sn on SiO2-Al2O3 was found to be the optimum catalyst loading, resulting in 81% acetic acid conversion with 95% ethanol selectivity at 2 MPa and 270 °C. Further increase in ethanol selectivity would require prevention of esterification of acetic acid with ethanol, which leads to formation of ethyl acetate as by-product. The effect of catalyst acidity on acetic acid conversion and ethanol selectivity was studied and it was observed that proton donating capability of the support leads to the formation of ethyl acetate as by-product which, in turn, reduces ethanol selectivity. The ethanol synthesis reaction and esterification reaction over Bronsted acid sites takes place in series. The rate of esterification reaction was found to be highly dependent on the Bronsted acid density of the catalysts. Other catalyst parameters have little role on ethyl acetate yield.
A green approach to ethyl acetate: Quantitative conversion of ethanol through direct dehydrogenation in a Pd-Ag membrane reactor
Zeng, Gaofeng,Chen, Tao,He, Lipeng,Pinnau, Ingo,Lai, Zhiping,Huang, Kuo-Wei
, p. 15940 - 15943 (2012)
Pincers do the trick: The conversion of ethanol to ethyl acetate and hydrogen was achieved using a pincer-Ru catalyst in a Pd-Ag membrane reactor. Near quantitative conversions and yields could be achieved without the need for acid or base promoters or hydrogen acceptors (see scheme).
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Connor,Adkins
, p. 3420,3421, 3422 (1932)
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Catalytic Conversion of Ethanol to n-Butanol Using Ruthenium P-N Ligand Complexes
Wingad, Richard L.,Gates, Paul J.,Street, Steven T. G.,Wass, Duncan F.
, p. 5822 - 5826 (2015)
We report several ruthenium catalysts incorporating mixed donor phosphine-amine ligands for the upgrade of ethanol to the advanced biofuel n-butanol, which show high selectivity (≥90%) at good (up to 31%) conversion. In situ formation of catalysts from mixtures of [RuCl2(η6-p-cymene)]2 and 2-(diphenylphosphino)ethylamine (1) shows enhanced activity at initial water concentrations higher than those of our previously reported diphosphine systems. Preliminary mechanistic studies (electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy) suggest the possibility of ligand-assisted proton transfer in some derivatives.
Catalytic Transformation of Ethanol over Microporous Vanadium Silicate Molecular Sieves with MEL Structure (VS-2)
Kannan,Sen,Sivasanker
, p. 304 - 310 (1997)
The transformation of ethanol was carried out over vanadium silicate molecular sieves with MEL topology (VS-2) with different Si/V atomic ratios in the temperature range 523-623 K. The reaction was performed in a fixed-bed down-flow reactor at atmospheric pressure. Acetaldehyde, diethyl ether, and ethylene were the major products along with small amounts of acetone, acetic acid, ethyl acetate, and carbon oxides. The conversion increased while the selectivity toward acetaldehyde decreased with increase in reaction temperature. The kinetics of the reaction (at 5% conversion) indicated a nearly first-order dependence of the rate of formation of the major products on ethanol. The formation of acetaldehyde is suggested to be mainly through the involvement of the vanadyl species (V=O) while diethyl ether production is controlled by the simultaneous involvement of V=O and V-O-Si associated with vanadium in the lattice. The intrinsic activity of vanadium incorporated into the zeolite framework is nearly 10 times that of the vanadium present in the impregnated sample. The nature of the sites involved in the formation of the different products, as elucidated from spectroscopic techniques (NMR and ESR), and the possible reaction mechanisms are proposed.
Production of Pure Aqueous13C-Hyperpolarized Acetate by Heterogeneous Parahydrogen-Induced Polarization
Kovtunov, Kirill V.,Barskiy, Danila A.,Shchepin, Roman V.,Salnikov, Oleg G.,Prosvirin, Igor P.,Bukhtiyarov, Andrey V.,Kovtunova, Larisa M.,Bukhtiyarov, Valerii I.,Koptyug, Igor V.,Chekmenev, Eduard Y.
, p. 16446 - 16449 (2016)
A supported metal catalyst was designed, characterized, and tested for aqueous phase heterogeneous hydrogenation of vinyl acetate with parahydrogen to produce13C-hyperpolarized ethyl acetate for potential biomedical applications. The Rh/TiO2catalyst with a metal loading of 23.2 wt % produced strongly hyperpolarized13C-enriched ethyl acetate-1-13C detected at 9.4 T. An approximately 14-fold13C signal enhancement was detected using circa 50 % parahydrogen gas without taking into account relaxation losses before and after polarization transfer by magnetic field cycling from nascent parahydrogen-derived protons to13C nuclei. This first observation of13C PHIP-hyperpolarized products over a supported metal catalyst in an aqueous medium opens up new possibilities for production of catalyst-free aqueous solutions of nontoxic hyperpolarized contrast agents for a wide range of biomolecules amenable to the parahydrogen induced polarization by side arm hydrogenation (PHIP-SAH) approach.
High-purity alkoxychlorosilanes as new precursors for precipitation of silica
Mirskov,Rakhlin,Adamovich,Voronkov
, p. 194 - 196 (2008)
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Synthesis of acetic acid from ethanol-water mixture over Cu/ZnO-ZrO 2-Al2O3 catalyst
Brei, Volodymyr V.,Sharanda, Mykhailo E.,Prudius, Svitlana V.,Bondarenko, Eugenia A.
, p. 196 - 200 (2013)
It was shown that acetic acid can be obtained from aqueous ethanol (6-40 mol%) solutions over Cu/ZnO-ZrO2-Al2O3 catalyst at 250-320 C and atmospheric pressure. Selectivity of 80-90% and space-time yield of acetic acid up to 9 mmol gcat-1 h-1 at 60-80% ethanol conversion were obtained while processing 14-37 mol% aqueous ethanol solutions. Hydrogen was generated in an amount ~2 moles per 1 mole of acetic acid as a co-product.
Revised Mechanisms for Aldehyde Disproportionation and the Related Reactions of the Shvo Catalyst
Gusev, Dmitry G.,Spasyuk, Denis M.
, p. 6851 - 6861 (2018)
It is widely believed that the Shvo catalyst (1) dissociates to form two active species in solution: the 18-electron hydride RuH(CO)2[η5-C5(OH)Ph4] (2) and the naked 16-electron complex Ru(CO)2[η4-C5(=O)Ph4] (3). This combined experimental/computational study demonstrates that a sustained presence of 3 is not viable in the reactions of alcohols and organic carbonyls; thus, 3 is better treated as nonexistent under the typical catalytic conditions. We propose a modified view where the key catalytic species are the hydride 2 and the 18-electron metal alkoxide intermediate Ru(OR)(CO)2[η5-C5(OH)Ph4] existing in equilibrium with the corresponding alcohol complex. An X-ray crystallographic study of 2 revealed an interesting dihydrogen-bonded dimer structure in the solid state. The mechanistic ideas of this paper explain the highly efficient Tishchenko-like aldehyde disproportionation reaction with the Shvo catalyst. Additionally, our observations explain why 1 is inefficient for hydrogenation of ethyl acetate and for the acceptorless dehydrogenative coupling of ethanol. Our findings provide practical guidance for future catalyst design on the basis of the Shvo ruthenium dimer prototype.
Deeper Mechanistic Insight into Ru Pincer-Mediated Acceptorless Dehydrogenative Coupling of Alcohols: Exchanges, Intermediates, and Deactivation Species
Nguyen, Duc Hanh,Trivelli, Xavier,Capet, Frédéric,Swesi, Youssef,Favre-Réguillon, Alain,Vanoye, Laurent,Dumeignil, Franck,Gauvin, Régis M.
, p. 4719 - 4734 (2018)
The mechanism of acceptorless dehydrogenative coupling reaction (ADC) of alcohols to esters catalyzed by aliphatic pincer PHNP ruthenium complexes was experimentally studied. Relevant intermediate species involved in the catalytic cycle were isolated and structurally characterized by single-crystal X-ray diffraction studies, and their reactivity (including toward substrates related to the catalytic process) was probed. VT NMR studies unveiled several chemical exchanges connecting the Ru amido hydride, the Ru alkoxide, and the alcohol substrate. Under catalytic conditions, in situ IR spectroscopy monitoring demonstrated the production of ester via aldehyde as intermediate. A Tishchenko-like pathway is proposed as the main path for the production of ester from aldehyde, involving alkoxide and hemiacetaloxide Ru species (the latter being identified in the reaction mixture by NMR). Catalytic system deactivation under base-free conditions was found to be related to water traces in the reaction medium (either as impurity or derived from aldol reactions) that lead to the formation of catalytically inactive acetato Ru complexes. These react with alkali metal alkoxides to afford catalytically active Ru species. In line with this observation, running the ADC reaction in the presence of water scavengers or alkoxides allows maintaining sustained catalytic activity.
Impact of the Oxygen Vacancies on Copper Electronic State and Activity of Cu-Based Catalysts in the Hydrogenation of Methyl Acetate to Ethanol
Xi, Yushan,Wang, Yue,Yao, Dawei,Li, Antai,Zhang, Jingyu,Zhao, Yujun,Lv, Jing,Ma, Xinbin
, (2019)
Reducible oxides supported copper-based catalysts have been widely used in ester hydrogenations due to their excellent catalytic performance. However, the role of surface oxygen vacancies is still unclear. Here, we fabricated four copper-based catalysts u
RADICAL TELOMERIZATION OF 3,3,3-TRIFLUOROPROPENE WITH 2-METHYL-1,3-DIOXOLANE
Terent'ev, A.B.,Pastushenko, E.V.,Kruglov, D.E.,Ryabinina, T.A.
, p. 2197 - 2200 (1992)
The telomerization of 3,3,3-trifluoropropene with 2-methyl-1,3-dioxolane gives predominantly cyclic telomers as shown by 13C NMR and gas chromatography-mass spectrometry.This reaction is accompanied by the rearrangement of transient free radical intermediates via 1,5-H-migration. Keywords: radicals, addition, dioxolane, telomers, telomerization, kinetics.
Effect of Support in Ethanol Oxidation on Molybdenum Oxide
Zhang, Weimin,Desikan Anantha,Oyama, S. Ted
, p. 14468 - 14476 (1995)
The oxidation of ethanol on MoO3 supported on SiO2, Al2O3, and TiO2 was studied in a flow reactor at atmospheric pressure.The reactivity sequence followed the order MoO3/TiO2 > MoO3/Al2O3 > MoO3/SiO2 and correlated with the reducibility of the surface molybdenum species.Ethanol oxidation produces mainly acetaldehyde, diethyl ehter, and ethylene through ethoxide type intermediates adsorbed on different sites (M=O, Mo-O-Mo, or Mo-O-M).Two types of ethoxide species were identified using laser Raman spectroscopy under in situ conditions and could be associated with the Mo=O and Mo-O-Mo sites.Although rates were strongly affected by the support, suggesting that activity was controlled by a term in the preexponential factor.The link to reducibility and the existence of a common ethoxide intermediate indicated that the controlling factor was likely to be the electronic partition function associated with the density of electron-accepting levels in the molybdate-support complex.
Facile synthesis of homogeneous CsxWO3 nanorods with excellent low-emissivity and NIR shielding property by a water controlled-release process
Guo, Chongshen,Yin, Shu,Yan, Mei,Sato, Tsugio
, p. 5099 - 5105 (2011)
A systematic investigation of the synthesis of homogenous Cs xWO3 nanorods by a designed water-controlled release process was carried out. The results revealed that the uniform rod-like Cs xWO3 nanoparticles with a Cs/W atomic ratio of ca. 0.33 can be obtained by using 20 vol% CH3COOH-80 vol% CH 3CH2OH mixed solution as a reaction solvent at 240°C for 20 h. The morphology of products were changed depending on the speed of water-releasing process, meanwhile, the Cs/W atomic ratio could be controlled by both the amount of released water and the reaction temperature. Cs xWO3 nanorods showed a high transmittance in the visible light region and excellent shielding ability of near infrared (NIR) lights, indicating that CsxWO3 nanorods have a suitable characteristic as solar filter applications. The Royal Society of Chemistry 2011.
Highly selective 1-butanol obtained from ethanol catalyzed by mixed metal oxides: Reaction optimization and catalyst structure behavior
Rechi Siqueira, Marcos,Micali Perrone,Metzker, Gustavo,de Oliveira Lisboa, Daniela Correa,Thoméo, Jo?o Cláudio,Boscolo, Maurício
, (2019)
Synthesis and characterization of a copper mixed metal oxide obtained from hydrotalcite precursor as well as catalytic runs for ethanol conversion to 1-butanol are described. Applying the surface response model, the reaction was optimized reaching an ethanol conversion of 79.6% into gaseous phase (69% of yield) and condensed phase (31% of yield) products using a batch reactor at 350 °C for 5 h. The main product of the condensed phase was 1-butanol with 25.4% yield and 32% selectivity, these results being among the higher ones reported for this reaction in the literature. Recycling catalyst experiments demonstrated that, for at least four cycles, the ethanol conversion remains almost constant but the 1-butanol yield and selectivity both decreased. XRD, EPR, surface area measurements and acidity/basicity experiments carried out after the first and fourth catalyst recycling cycles show major modifications in the initial mixed metal oxide structure and copper oxidation state indicating that the active catalytic species increases during the first catalytic run.
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Ruggli et al.
, p. 411,413 (1939)
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Thermal decomposition of acetyl propionyl peroxide in acetone-d6
Skakovskii,Stankevich,Tychinskaya,Shirokii,Choban,Murashko,Rykov
, p. 1719 - 1725 (2004)
The kinetics of thermolysis of acetyl propinyl peroxide in acetone-d 6 in the temperature range 323-373 K was studied using NMR spectroscopy and the effect of chemically induced nuclear polarization. The peroxide decomposes in acetone at rates comparable with the rates of thermolysis in alcohols, yielding numerous products. In the examined temperature range, the solvent molecules act as efficient donors of deuterium atoms, forming acetylmethyl-d5 radicals which recombine to a significant extent with the peroxide radicals. A scheme of the processes involved in decomposition of the peroxide was suggested. The parameters of the Arrhenius equation for the peroxide decomposition were determined. 2004 MAIK "Nauka/ Interperiodica".
The Reaction of with Triethoxysilane in the Presence of PPh3: a New Method for Synthesis of
Marciniec, Bogdan,Maciejewski, Hieronim,Gulinski, Jacek
, p. 717 - 718 (1995)
The reaction of with triethoxysilane in the presence of PPh3 is examined under oxygen-free conditions, permitting isolation of 1 formed by elimination of one acac ligand (as protonated and hydrosilylated product) from the nickel complex with its simultaneous silylation which is followed by C-O bond cleavage in triethoxysilyl ligand via a mechanism involving transfer of an ethyl group to Ni with elimination of pentaethoxyhydrodisiloxane in the excess of triethoxysilane.
DEUTERIUM ISOTOPE EFFECTS IN THE THERMAL DECOMPOSITION OF β-HYDROXY KETONES AND β-HYDROXY ESTERS
Quijano, J.,Rodriguez, M. M.,Yepes, M. del S.,Gallego, L.H.
, p. 3555 - 3558 (1987)
Small primary and cumulative secondary isotope effects are determined experimentally by thermolysis of various β-hydroxy ketones and β-hydroxy esters.
Dehydrogenative ester synthesis from enol ethers and water with a ruthenium complex catalyzing two reactions in synergy
Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Luo, Jie,Milstein, David,Rauch, Michael
supporting information, p. 1481 - 1487 (2022/03/07)
We report the dehydrogenative synthesis of esters from enol ethers using water as the formal oxidant, catalyzed by a newly developed ruthenium acridine-based PNP(Ph)-type complex. Mechanistic experiments and density functional theory (DFT) studies suggest that an inner-sphere stepwise coupled reaction pathway is operational instead of a more intuitive outer-sphere tandem hydration-dehydrogenation pathway.
Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
, p. 11572 - 11581 (2021/10/12)
A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.