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Cas Database

141-78-6

141-78-6

Identification

  • Product Name:Ethyl acetate

  • CAS Number: 141-78-6

  • EINECS:205-500-4

  • Molecular Weight:88.1063

  • Molecular Formula: C4H8O2

  • HS Code:2915.39

  • Mol File:141-78-6.mol

Synonyms:Ethyl ethanoate;Ethyl ester;Acetic ester;Ester of ethanol;AI3-00404;Acetate d'ethyle;Acetic acid, ethyl ester;Acetidin;Acetoxyethane;Aethylacetat;

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Safety information and MSDS view more

  • Pictogram(s):FlammableF,IrritantXi

  • Hazard Codes:F,Xi,Xn,T

  • Signal Word:Danger

  • Hazard Statement:H225 Highly flammable liquid and vapourH319 Causes serious eye irritation H336 May cause drowsiness or dizziness

  • First-aid measures: General adviceConsult a physician. Show this safety data sheet to the doctor in attendance.If inhaled Fresh air, rest. Refer for medical attention. In case of skin contact Rinse contaminated clothes (fire hazard) with plenty of water. Remove contaminated clothes. Rinse skin with plenty of water or shower. In case of eye contact Rinse with plenty of water for several minutes (remove contact lenses if easily possible). If swallowed Rinse mouth. Seek medical attention if you feel unwell. Headache, irritation of respiratory passages and eyes, dizziness and nausea, weakness, loss of consciousness. (USCG, 1999) Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Esters and related compounds/

  • Fire-fighting measures: Suitable extinguishing media Cool exposed containers with water. Excerpt from ERG Guide 129 [Flammable Liquids (Water-Miscible / Noxious)]: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. (ERG, 2016) Wear self-contained breathing apparatus for firefighting if necessary.

  • Accidental release measures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. For personal protection see section 8. Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Do NOT wash away into sewer. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations. ACCIDENTAL RELEASE MEASURES. Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapours accumulating to form explosive concentrations. Vapours can accumulate in low areas.; Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains.; Methods and materials for containment and cleaning up: Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing and place in container for disposal according to local regulations.

  • Handling and storage: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Avoid exposure - obtain special instructions before use.Provide appropriate exhaust ventilation at places where dust is formed. For precautions see section 2.2. Fireproof. Separated from strong oxidants, strong bases and strong acids.Keep tightly closed in cool place.

  • Exposure controls/personal protection:Occupational Exposure limit valuesRecommended Exposure Limit: 10 Hour Time-Weighted Average: 400 ppm (1400 mg/cu m).Biological limit values Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday. Eye/face protection Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU). Skin protection Wear impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace. Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique(without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands. The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it. Respiratory protection Wear dust mask when handling large quantities. Thermal hazards

Supplier and reference price

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  • Manufacture/Brand:TRC
  • Product Description:Ethyl acetate
  • Packaging:1000ml
  • Price:$ 185
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  • Manufacture/Brand:TCI Chemical
  • Product Description:Ethyl Acetate [for Spectrophotometry] >99.5%(GC)
  • Packaging:250mL
  • Price:$ 36
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  • Manufacture/Brand:TCI Chemical
  • Product Description:Ethyl Acetate [Sequencing Solvent]
  • Packaging:500ML
  • Price:$ 34
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl acetate biotech. grade, ≥99.8%
  • Packaging:2l
  • Price:$ 143
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl acetate for gas chromatography MS SupraSolv . CAS 141-78-6, EC Number 205-500-4, chemical formula CH COOC H ., for gas chromatography MS SupraSolv
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  • Price:$ 143
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl acetate for gas chromatography ECD and FID SupraSolv . CAS 141-78-6, EC Number 205-500-4, chemical formula CH COOC H ., for gas chromatography ECD and FID SupraSolv
  • Packaging:1109722500
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl acetate
  • Packaging:1
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl acetate solution
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl acetate OmniSolv?
  • Packaging:4 L
  • Price:$ 188.7
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  • Manufacture/Brand:Sigma-Aldrich
  • Product Description:Ethyl Acetate Pharmaceutical Secondary Standard; Certified Reference Material
  • Packaging:20ml
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Relevant articles and documentsAll total 518 Articles be found

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Lane et al.

, p. 6492 (1968)

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Activated carbon aerogel supported copper catalysts for the hydrogenation of methyl acetate to ethanol: Effect of KOH activation

Hou, Xiaoxiong,Zhao, Jinxian,Liu, Junjie,Han, Yahong,Pei, Yongli,Ren, Jun

, p. 9430 - 9438 (2019)

Methyl acetate (MA) hydrogenation is crucial for indirect ethanol synthesis through syngas (CO + H2). In our work, activated carbon aerogel supported copper (Cu-ACA) catalysts have been prepared by a conventional impregnation method. The surface area and functional groups of the ACA soared after KOH activation. The highest surface area achieved for the ACA was 2562 m2 g-1. The anchoring effect of micropores and external oxygen-containing groups (OCGs) significantly enhanced the metal-support interaction in catalysts, facilitating the high dispersion of Cu and an enhancement in surface Cu+ species, both of which improved the catalytic activity of catalysts. Cu-ACA-A4 showed the most outstanding catalytic performance, with a MA conversion of 95.2% and an ethanol selectivity of 62.2%, close to the carbon equilibrium selectivity of 66.7%.

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.

THERMAL DECOMPOSITION OF PEROXIDE DERIVATIVES OF POLYFLUORINATED β-KETOESTERS

Rakhimov, A. I.,Chapurkin, V. V.,Val'dman, A. I.,Val'dman, D. I.,Saloutin, V. I.,et al.

, (1990)

The thermal flow microcalorimetric method was used to determine the kinetic parameters for the thermal decomposition of peroxide derivatives of polyfluorinated β-ketoesters and the decomposition products were established.

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.

SPLITTING OF C-C BONDS IN β-DICARBONYL COMPOUNDS CATALYZED BY TRANSITION METAL COMPLEXES

Akhrem, I. S.,Vartanyan, R. S.,Afanas'eva, L. V.,Vol'pin, M. E.

, p. 1217 - 1220 (1983)

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A dinuclear strontium(II) complex as substrate-selective catalyst of ester cleavage

Cacciapaglia,Di Stefano,Mandolini

, p. 5926 - 5928 (2001)

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RADICAL REACTION OF ETHYL ORTHOACETATE WITH 3,3,3-TRIFLUOROPROPENE

Khatuntsev, I. I.,Pastushenko, E. V.,Terent'ev, A. B.

, p. 1435 - 1438 (1986)

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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.

Kinetics of ethanol dehydrogenation into ethyl acetate

Men'Shchikov,Gol'Dshtein,Semenov

, p. 12 - 17 (2014)

The kinetics of gas-phase dehydrogenation of ethanol into ethyl acetate over a copper-zinc-chromium catalyst has been investigated in a flow reactor at pressures of 10-20 atm and temperatures of 230-290 C. For the process occurring under kinetic control, the rate constants of two reactions and the adsorption constants of five components have been determined using the Langmuir-Hinshelwood model. A kinetic model has been developed for the process. This model provides means to design a reactor for dehydrogenation of ethanol into ethyl acetate in different regimes.

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 over supported platinum catalysts

Rachmady,Vannice

, p. 322 - 334 (2000)

The kinetic behavior of acetic acid hydrogenation over platinum supported on TiO2, SiO2, η-Al2O3, and Fe2O3 was studied in a differential, fixed-bed reactor at 423-573 K, 100-700 torr hydrogen, and 7-50 torr acetic acid. The interaction of acetic acid with the oxide support played a major role in determining the kinetics of the reaction, and platinum served as a source of mobile, activated hydrogen atoms. During hydrogenation at low conversions, carbon-containing products consisted of about 50% CO and 50% CH4 over Pt/SiO2; 50% ethanol, 30% ethyl acetate, and 20% ethane over Pt/TiO2 reduced at 473 or 773 K; 40% CH4, 10% ethane, 8% ethanol, 4% ethyl acetate, 33% CO, and 5% CO2 over Pt/η-Al2O3; and 80% acetaldehyde and 20% ethanol over Pt/Fe2O3. Pt/TiO2 catalysts were the most active, with activities and turnover frequencies being ≤ 2 orders of magnitude larger than those for the other catalysts. The apparent reaction order with respect to H2 varied between 0.4 and 0.6, while that with respect to acetic acid was 0.2-0.4. This study provided evidence that acetic acid hydrogenation over supported Pt catalysts can be described by a Langmuir-Hinshelwood-type mechanism invoking two sites, one on the metal to activate H2 and one on the oxide to molecularly adsorb acetic acid. The kinetic rate expression derived from this reaction model fitted the data well with thermodynamically consistent parameters.

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.

Role of the Cu-ZrO2 Interfacial Sites for Conversion of Ethanol to Ethyl Acetate and Synthesis of Methanol from CO2 and H2

Ro, Insoo,Liu, Yifei,Ball, Madelyn R.,Jackson, David H. K.,Chada, Joseph Paul,Sener, Canan,Kuech, Thomas F.,Madon, Rostam J.,Huber, George W.,Dumesic, James A.

, p. 7040 - 7050 (2016)

Well-defined Cu catalysts containing different amounts of zirconia were synthesized by controlled surface reactions (CSRs) and atomic layer deposition methods and studied for the selective conversion of ethanol to ethyl acetate and for methanol synthesis. Selective deposition of ZrO2 on undercoordinated Cu sites or near Cu nanoparticles via the CSR method was evidenced by UV-vis absorption spectroscopy, scanning transmission electron microscopy, and inductively coupled plasma absorption emission spectroscopy. The concentrations of Cu and Cu-ZrO2 interfacial sites were quantified using a combination of subambient CO Fourier transform infrared spectroscopy and reactive N2O chemisorption measurements. The oxidation states of the Cu and ZrO2 species for these catalysts were determined using X-ray absorption near edge structure measurements, showing that these species were present primarily as Cu0 and Zr4+, respectively. It was found that the formation of Cu-ZrO2 interfacial sites increased the turnover frequency by an order of magnitude in both the conversion of ethanol to ethyl acetate and the synthesis of methanol from CO2 and H2.

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).

-

Hawes,Kabel

, p. 606,609 (1968)

-

-

Connor,Adkins

, p. 3420,3421, 3422 (1932)

-

-

Church,Joshi

, p. 1804 (1951)

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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.

Selective oxidation of ethanol over Ag, Cu and Au nanoparticles supported on Li2O/Γ-Al2O3

Silbaugh, Trent L.,Devlaminck, Pierre,Sofranko, John A.,Barteau, Mark A.

, p. 40 - 47 (2018)

In an effort to verify a previous striking report that ethanol could be oxidized selectively to ethylene oxide, ethanol oxidation on Ag, Cu, or Au nanoparticles supported on Li2O/γ-Al2O3 or γ-Al2O3 was examined between 100 and 400 °C. Ag and Cu catalysts were found to be highly selective to acetaldehyde (>95% on Ag below 325 °C and on Cu below 250 °C). On Au, selectivities to acetaldehyde were lower, with higher selectivity to ethyl acetate and acetic acid. No ethylene oxide was observed under any conditions. Our results, including selectivity variations among these metals, are consistent with previous studies of ethanol oxidation over coinage metals supported on γ-Al2O3, with no changes in primary product identity and minor changes in selectivity upon addition of Li2O. Unfortunately, these results are in direct contradiction to previous work reporting the desirable direct conversion of ethanol to ethylene oxide on Ag, Cu, and Au on Li2O/γ-Al2O3.

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.

Structural requirements and reaction pathways in condensation reactions of alcohols on MgyAlOx catalysts

Di Cosimo,Apesteguia,Gines,Iglesia

, p. 261 - 275 (2000)

A study of the effect of composition and of surface characteristics on alcohol-coupling reactions on MgyAlOx catalysts using C2H5OH or 13CH3OH/1-12C3H7OH mixtures as reactants showed that the biomolecular and consecutive character of the condensation reactions were affected by the catalyst acid-base properties and by the chemical nature of the alcohols and steric factors. The rates and product selectivity for C2H5OH or CH3OH/C3H7OH reactions strongly depended on the chemical composition of Mgy/AlOx samples. The chemical composition affected the acid-base properties of MgyAlOx samples. The rate of alcohol dehydration to ethers and olefins increased with increases in Al content. Al-rich MgyAlOx samples contained a high density of Al3+-O2- site pairs and of moderate strength basic sites, the combination of which promoted ethylene or propylene formation from primary alcohols via E2 elimination pathways. The competitive dehydration to form ethers involved the adsorption of two alcohol molecules on neighboring acid sites offering various acid-base properties. On MgyAlOx samples, the active acid sites for ether formation were possibly the Al3+ cations and the basic sites were the neighboring O2- ions. The dehydrogenation of alcohols to aldehydes involved the initial alkoxy intermediate formation on weak Lewis acid-strong Broensted base site pairs. The synthesis of C2H4O or C3H6O was favored on Mg-rich MgyAlOx samples, which contained a larger number of property positioned Al3+ Lewis acid sites and Mg2+-O2- basic pairs required for hydrogen abstraction steps leading to alkoxy intermediates. Pure MgO showed lower dehydrogenation rates than Mg-rich MgyAlOx samples. Aldol condensation reactions on MgyAlOx samples also involved the formation of a carbanion intermediate on Lewis acid-strong Broensted base pair sites and produced products with a novel C-C bond, e.g., n-C4H8O and iso-C4H8O. Reactions leading to condensation products were also favored on Mg-rich samples.

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.

Synthesis of methyl propanoate by Baeyer-Villiger monooxygenases

Van Beek, Hugo L.,Winter, Remko T.,Eastham, Graham R.,Fraaije, Marco W.

, p. 13034 - 13036 (2014)

Methyl propanoate is an important precursor for polymethyl methacrylates. The use of a Baeyer-Villiger monooxygenase (BVMO) to produce this compound was investigated. Several BVMOs were identified that produce the chemically non-preferred product methyl propanoate in addition to the normal product ethyl acetate. This journal is

High-purity alkoxychlorosilanes as new precursors for precipitation of silica

Mirskov,Rakhlin,Adamovich,Voronkov

, p. 194 - 196 (2008)

-

Low-Flammable Parahydrogen-Polarized MRI Contrast Agents

Ariyasingha, Nuwandi M.,Chekmenev, Eduard Y.,Chukanov, Nikita V.,Gelovani, Juri G.,Joalland, Baptiste,Koptyug, Igor V.,Kovtunov, Kirill V.,Nantogma, Shiraz,Salnikov, Oleg G.,Younes, Hassan R.

, p. 2774 - 2781 (2021)

Many MRI contrast agents formed with the parahydrogen-induced polarization (PHIP) technique exhibit biocompatible profiles. In the context of respiratory imaging with inhalable molecular contrast agents, the development of nonflammable contrast agents would nonetheless be highly beneficial for the biomedical translation of this sensitive, high-throughput and affordable hyperpolarization technique. To this end, we assess the hydrogenation kinetics, the polarization levels and the lifetimes of PHIP hyperpolarized products (acids, ethers and esters) at various degrees of fluorine substitution. The results highlight important trends as a function of molecular structure that are instrumental for the design of new, safe contrast agents for in vivo imaging applications of the PHIP technique, with an emphasis on the highly volatile group of ethers used as inhalable anesthetics.

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.

Direct synthesis of ethyl acetate from ethanol carried out under pressure

Inui, Kanichiro,Kurabayashi, Toru,Sato, Satoshi

, p. 207 - 215 (2002)

Direct synthesis of ethyl acetate from ethanol over a Cu-Zn-Zr-AI-O catalyst was studied under pressured conditions between 473 and 533 K. The selectivity to ethyl acetate and the space-time yield of ethyl acetate increased with increasing reaction pressure, whereas ethanol conversion decreased. The highest spacetime yield of ethyl acetate was achieved at a reaction pressure of about 0.8 MPa with maximum selectivity of 93 wt %. The products observed in the effluent include ethyl acetate, acetaldehyde, butanone, 1-butanol, and propanone. In the reaction of acetaldehyde in a flow of N2 hardly any converted to ethyl acetate and a small amount of acetaldol derivatives, e.g., 2-butenal and butanal, were observed. In contrast, the reaction of acetaldehyde in an H2 flow was accompanied by the formation of ethyl acetate as a major product and hydrogenated products, e.g., ethanol and 1-butanol. In the reaction of an equimolar mixture of acetaldehyde and ethanol in an N2 flow, the product distribution was also similar to that observed in the reaction of ethanol. Butanone was the major product of the 1,3-butanediol reaction.

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.

Gas-Phase Acylation Reactions. Substrate and Positional Selectivity of Free Acetylium Ions toward Methylbenzenes

Speranza, Maurizio,Sparapani, Cinzia

, p. 3120 - 3124 (1980)

Free acetylium ions, obtained in the diluted gas state from the γ radiolysis of CH3F-CO mixtures, have been allowed to react with methylbenzenes, in the pressure range 380-760 Torr, and in the presence of a gaseous base (NH3).The gaseous cation has been confirmed to be unreactive toward benzene and toluene, whereas it acetylates the xylenes and the other selected polymethylated benzenes.The relative rates of acetylation have been determined in competition experiments, using mesitylene as the reference substrate.The mechanism of acetylation and subsequent isomerization is discussed, and the substrate and positional selectivity of the free CH3CO+ ion are evaluated, together with its intrinsic steric requirements.Comparison of the gas-phase results with those of related condensed-phase reactions, involving CH3CH+ salts as one of the reactive species, reveals no basic mechanistic differences.Some observed reactivity and selectivity discrepancies, in particular those concerning acetylation of toluene, o- and m-xylene, and hemimellitene, are outlined and their possible causes considered.

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.

Copper-mediated decarboxylative coupling of benzamides with potassium malonate monoesters via directed CH cleavage

Takamatsu, Kazutaka,Hirano, Koji,Miura, Masahiro

, p. 450 - 453 (2018)

A copper-mediated decarboxylative coupling of benzamides with potassium malonate monoesters via 8-aminoquinoline-directed CH cleavage has been developed. This reaction proceeds only by a copper salt to produce the corresponding alkylation products in good

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

ALKANEPERSULFONIC ACIDS AS NEW OXIDIZING AGENTS IN THE BAYER-VILLIGER REACTION

Safiullin, R. L.,Volgarev, A. N.,Komissarov, V. D.,Tolstikov, G. A.

, p. 1998 (1990)

-

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.

FeSBA-15-supported ruthenium catalyst for the selective hydrogenolysis of carboxylic acids to alcoholic chemicals

Li, Wenjing,Ye, Linmin,Chen, Jin,Duan, Xinping,Lin, Haiqiang,Yuan, Youzhu

, p. 53 - 59 (2015)

Ordered mesoporous FeSBA-15-supported Ru catalysts are characterized by N2 adsorption-desorption isotherm, H2-temperature-programmed reduction, X-ray fluorescence, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analyses. Results suggest the co-existence of Fe oxide species highly dispersed in the frameworks of SBA-15 and Ru-Fe bimetallic nanoparticles. The concentration of Fe species is low and in the form of Ru-Fe alloys located on the catalyst surfaces following reduction pretreatment in 5% H2-95% N2 flow at 623 K for 4 h. The as-reduced Ru/FeSBA-15 catalysts efficiently and selectively hydrogenolyze short-chain carboxylic acids (e.g., acetic acid, propionic acid, butyric acid, levulinic acid, and lactic acid) to their corresponding alcoholic chemicals. Results indicate that 2% Ru/FeSBA-15 catalyst with 1.07% Fe content yields the highest performance and excellent stability, yielding 92.5% conversion of acetic acid and 85.2% selectivity to ethanol under optimized conditions. The improved catalytic performance of the FeSBA-15-supported Ru catalyst is mainly attributed to the coherent interactions between Fe and Ru species, as well as to the high dispersion of Fe oxides in the SBA-15 framework.

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.

Bifunctional mesoporous organic-inorganic hybrid silica for combined one-step hydrogenation/esterification

Tang, Yang,Miao, Shaojun,Shanks, Brent H.,Zheng, Xiaoming

, p. 310 - 317 (2010)

Bifunctional mesoporous organic-inorganic hybrid silicas with platinum and propylsulfonic acid group (Pt/SBA15-PrSO3H) were synthesized and tested for the combined one-step hydrogenation/esterification (OHE) reaction, which was employed as a model reaction for catalytic upgrading of biomass-derived bio-oil. The model reagents used were acetic acid and acetaldehyde. Different catalyst synthesis procedures were investigated and compared by varying the functional group incorporation method, platinum loading, reducing agent, etc. The textural and chemical properties of the catalysts made by the different synthesis procedures were characterized and compared with reactivity results. The need to create the organic acid sites prior to platinum incorporation was demonstrated. The efficacy of the bifunctional catalyst system for combined hydrogenation/esterification was demonstrated. Interestingly, the bifunctional Pt/SBA15-PrSO3H catalyst exhibited superior esterification activity with about twice the acetic acid turnover number relative to that with the monofunctional SBA15-PrSO3H catalyst. By combining metallic Pt nanoparticles with strong acid sites, this bifunctional mesoporous hybrid catalyst improved OHE activity and, therefore, has potential for application in the catalytic upgrading of bio-oil.

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.

Esterase activities of Brevibacterium sp. R312 and Brevibacterium linens 62

Lambrechts,Galzy

, p. 1464 - 1471 (1995)

-

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.

Structural investigation of solid-acid-promoted Pd/SDB catalysts for ethyl acetate production from ethanol

Lee,Zheng,Chang

, p. 3400 - 3404 (2001)

Catalyzed by styrene-divinylbenzene copolymer (SDB)-supported Pd (Pd/SDB) catalysts, ethyl acetate can be formed from water-containing ethanol via concomitant partial oxidation and esterification reaction. The partial oxidation reaction is carried out ove

-

Ruggli et al.

, p. 411,413 (1939)

-

-

Kagan,Ssobolew,Ljubarski

, p. 1142 (1935)

-

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".

Facile Preparation of Methyl Phenols from Ethanol over Lamellar Ce(OH)SO4· xH2O

Guo, Jinqiu,Feng, Zongjing,Xu, Jun,Zhu, Jie,Zhang, Guanghui,Du, Yaping,Zhang, Hongbo,Yan, Chunhua

, p. 6162 - 6174 (2021)

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

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.

Removal of the copper catalyst from atom transfer radical polymerization mixtures by chemical reduction with zinc powder

Canturk, Fatma,Karagoz, Bunyamin,Bicak, Niyazi

, p. 3536 - 3542 (2011)

Simple mixing of an atom transfer radical polymerization (ATRP) mixture with zinc powder was demonstrated to result in rapid decolorizing of the solution and precipitation of elemental copper, using small amounts of silica gel as seeding material. The experiments revealed that the chemical reduction of copper by wetted zinc powder (i.e., 0.325 g/mmol copper) is fast and completed within less than 5 min. UV spectra of the filtered polymer solution showed no any trace of copper. Terminal bromoalkyl groups of the polymers in the ATRP solution were determined to be unchanged by short-term contact with zinc powder at room temperature and a nearly complete reductive dehalogenation takes place only after 24 h of interaction, as evidenced by reaction of elemental zinc with a model compound, ethyl bromoacetate. Indeed, poly(methyl methacrylate) (PMMA) sample (Mn: 7900, polydispersity index: 1.09) isolated from ATRP mixture after the copper removal a by short contact with zinc powder (i.e., 15 min) was determined "still living" as confirmed by chain extension with styrene, ethyl acrylate, and t-butyl acrylate monomers to give block copolymers. The presence of acetic acid was demonstrated to accelerate reductive dehalogenation of PMMA end-groups by zinc and yields nonliving polymer within 2 h.

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.

Insight into the balancing effect of active Cu species for hydrogenation of carbon-oxygen bonds

Wang, Yue,Shen, Yongli,Zhao, Yujun,Lv, Jing,Wang, Shengping,Ma, Xinbin

, p. 6200 - 6208 (2015)

Hydrogenation of carbon-oxygen (C-O) bonds plays a significant role in organic synthesis. Cu-based catalysts have been extensively investigated because of their high selectivity in C-O hydrogenation. However, no consensus has been reached on the precise roles of Cu0 and Cu+ species for C-O hydrogenation reactions. Here we resolve this long-term dispute with a series of highly comparable Cu/SiO2 catalysts. All catalysts represent the full-range distribution of the Cu species and have similar general morphologies, which are detected and mutually corroborated by multiple characterizations. The results demonstrate that, when the accessible metallic Cu surface area is below a certain value, the catalytic activity of hydrogenation linearly increases with increasing Cu0 surface area, whereas it is primarily affected by the Cu+ surface area. Furthermore, the balancing effect of these two active Cu sites on enhancing the catalytic performance is demonstrated: the Cu+ sites adsorb the methoxy and acyl species, while the Cu0 facilitates the H2 decomposition. This insight into the precise roles of active species can lead to new possibilities in the rational design of catalysts for hydrogenation of C-O bonds.

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.

Dual utility of a single diphosphine-ruthenium complex: A precursor for new complexes and, a pre-catalyst for transfer-hydrogenation and Oppenauer oxidation

Mukherjee, Aparajita,Bhattacharya, Samaresh

, p. 15617 - 15631 (2021/05/19)

The diphosphine-ruthenium complex, [Ru(dppbz)(CO)2Cl2] (dppbz = 1,2-bis(diphenylphosphino)benzene), where the two carbonyls are mutually cis and the two chlorides are trans, has been found to serve as an efficient precursor for the synthesis of new complexes. In [Ru(dppbz)(CO)2Cl2] one of the two carbonyls undergoes facile displacement by neutral monodentate ligands (L) to afford complexes of the type [Ru(dppbz)(CO)(L)Cl2] (L = acetonitrile, 4-picoline and dimethyl sulfoxide). Both the carbonyls in [Ru(dppbz)(CO)2Cl2] are displaced on reaction with another equivalent of dppbz to afford [Ru(dppbz)2Cl2]. The two carbonyls and the two chlorides in [Ru(dppbz)(CO)2Cl2] could be displaced together by chelating mono-anionic bidentate ligands, viz. anions derived from 8-hydroxyquinoline (Hq) and 2-picolinic acid (Hpic) via loss of a proton, to afford the mixed-tris complexes [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], respectively. The molecular structures of four selected complexes, viz. [Ru(dppbz)(CO)(dmso)Cl2], [Ru(dppbz)2Cl2], [Ru(dppbz)(q)2] and [Ru(dppbz)(pic)2], have been determined by X-ray crystallography. In dichloromethane solution, all the complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on the complexes shows redox responses within 0.71 to -1.24 V vs. SCE. [Ru(dppbz)(CO)2Cl2] has been found to serve as an excellent pre-catalyst for catalytic transfer-hydrogenation and Oppenauer oxidation.

Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst

Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett

supporting information, p. 2157 - 2161 (2021/05/21)

The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.

Process route upstream and downstream products

Process route

ethanol
64-17-5

ethanol

trimethylsilanyl-acetic acid ethyl ester
4071-88-9

trimethylsilanyl-acetic acid ethyl ester

ethyl trimethylsilyl ether
1825-62-3

ethyl trimethylsilyl ether

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
In ethanol; boiling of (CH3)3Si(CH2COOC2H5) in abs. ethanol for a longer period of time;;
ethyl bromoacetate
105-36-2

ethyl bromoacetate

hydrogen bromide
10035-10-6,12258-64-9

hydrogen bromide

acetaldehyde
75-07-0,9002-91-9

acetaldehyde

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
at 250 - 300 ℃;
diethyl ether
60-29-7,927820-24-4

diethyl ether

2-Bromoacetyl bromide
598-21-0

2-Bromoacetyl bromide

hydrogen bromide
10035-10-6,12258-64-9

hydrogen bromide

ethyl acetate
141-78-6

ethyl acetate

ethyl bromoacetate
105-36-2

ethyl bromoacetate

Conditions
Conditions Yield
ammonia
7664-41-7

ammonia

bis-ethoxycarbonylmethyl tin <sup>(2+)</sup>; diiodide
163555-14-4

bis-ethoxycarbonylmethyl tin (2+); diiodide

hydrogen iodide
10034-85-2

hydrogen iodide

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
water
7732-18-5

water

bis-ethoxycarbonylmethyl tin <sup>(2+)</sup>; diiodide
163555-14-4

bis-ethoxycarbonylmethyl tin (2+); diiodide

hydrogen iodide
10034-85-2

hydrogen iodide

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
bis-ethoxycarbonylmethyl tin <sup>(2+)</sup>; diiodide
163555-14-4

bis-ethoxycarbonylmethyl tin (2+); diiodide

hydrogen iodide
10034-85-2

hydrogen iodide

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
bis-ethoxycarbonylmethyl tin <sup>(2+)</sup>; diiodide
163555-14-4

bis-ethoxycarbonylmethyl tin (2+); diiodide

hydrogen iodide
10034-85-2

hydrogen iodide

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
bis-ethoxycarbonylmethyl tin <sup>(2+)</sup>; diiodide
163555-14-4

bis-ethoxycarbonylmethyl tin (2+); diiodide

hydrogen iodide
10034-85-2

hydrogen iodide

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
cis-(CO)4Fe(COCH<sub>3</sub>)COOC<sub>2</sub>H<sub>5</sub>

cis-(CO)4Fe(COCH3)COOC2H5

iron pentacarbonyl
13463-40-6,37220-42-1

iron pentacarbonyl

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
In dichloromethane-d2; decompn. at 5°C; monitored by (1)H- and (13)C-NMR;
trans-(CO)4Fe(COCH<sub>3</sub>)COOC<sub>2</sub>H<sub>5</sub>

trans-(CO)4Fe(COCH3)COOC2H5

iron pentacarbonyl
13463-40-6,37220-42-1

iron pentacarbonyl

ethyl acetate
141-78-6

ethyl acetate

Conditions
Conditions Yield
In dichloromethane-d2; decompn. at 5°C; monitored by (1)H- and (13)C-NMR;

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