- Iron-Catalyzed Epoxidation of Linear α-Olefins with Hydrogen Peroxide
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The combination of Fe(OTf)2 with N-methyl bis(picolylamine) (Me-bpa) L7 enables epoxidation of linear olefins including terminal, internal, and cyclic ones, using hydrogen peroxide as terminal oxidant under mild conditions. In the presence of picolinic acid as additive improved yields of epoxides up to 75 % have been achieved.
- Beller, Matthias,Budweg, Svenja,Junge, Kathrin,Li, Yong-Wang,Mao, Shuxin,Spannenberg, Anke,Wen, Xiaodong,Yang, Yong
-
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- Olefin epoxidation with ionic liquid catalysts formed by supramolecular interactions
-
This work demonstrated that the specific ionic liquids (ILs) have been designed via the supramolecular complexation between 18-crown-6 (CE) and ammonium peroxoniobate (NH4-Nb). The resultant ILs have been characterized by elemental analysis, FT-IR, Raman, NMR, DSC, conductivity measurement and MALDI-TOF, etc. The IL (CE-1) consisting of CE and ammonium peroxoniobate can be further coordinated with GLY to generate a new IL (CE-2), which showed both high catalytic activity in epoxidation with H2O2 and good recyclability. The characterization of 93Nb NMR spectra revealed that the peroxoniobate anions has demonstrated a structural evolution in the presence of hydrogen peroxide, in which Nb[dbnd]O species can be easily oxidized into the catalytically active niobium?peroxo species. Especially, the supramolecular complexation can provide suitable hydrophobicity, which ensured that the hydrophobic olefins and allylic alcohols were easily accessible to the catalytically active anions, and thus facilitated the epoxidation reaction. Notably, the supramolecular IL catalysts in this work exhibited a huge advantage of the easy availability, as compared with the previously reported peroxoniobate-based ILs. As far as we know, this is the first example of the highly selective epoxidation of olefins and allylic alcohols by using supramolecular ILs as catalysts.
- Ding, Bingjie,Hou, Zhenshan,Li, Difan,Ma, Wenbao,Yao, Yefeng,Zhang, Ran,Zheng, Anna,Zhou, Qingqing
-
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- Efficient and region-selective conversion of octanes to epoxides under ambient conditions: Performance of tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz)
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In this paper, is described the conversion of the octane group of hydrocarbons into industrially important epoxides using tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz). The role of hydrogen peroxide as a sacrificial oxygen donor during catalytic conversion to epoxides has been investigated. The performance of the catalyst has been evaluated in terms of turnover numbers (TON) and turnover frequencies (TOF) reported in this article.
- Krupadam, Reddithota J.,Nagababu, Penumaka,Paul, Perala Sudheer,Reddy, Thatiparthi Byragi
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p. 742 - 745
(2021/09/28)
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- 2,4,4,6,8,8-Hexanitro-2,6-diazaadamantane: A High-Energy Density Compound with High Stability
-
A novel high-performance energetic compound of the polynitroazaadamantane family, 2,4,4,6,8,8-hexanitro-2,6-diazaadamantane, was designed and synthesized from 1,5-cyclooctadiene by two routes. Based on the experimental and calculated results, it exhibits a surprisingly high density (1.959 g cm-3), high thermal stability (onset decomposition temperature of 235 °C), high positive heat of formation, and excellent detonation properties. These fascinating properties, which are comparable to those of CL-20, show great promise for potential applications as a high-energy density material.
- Zhang, Jian,Hou, Tianjiao,Zhang, Lin,Luo, Jun
-
supporting information
p. 7172 - 7176
(2018/11/25)
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- Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes
-
The article examines the newly designed and structurally characterized redox-active BIAN-derived [Ru(trpy)(R-BIAN)Cl]ClO4 ([1a]ClO4-[1c]ClO4), [Ru(trpy)(R-BIAN)(H2O)](ClO4)2 ([3a](ClO4)2-[3c](ClO4)2), and BIAO-derived [Ru(trpy)(BIAO)Cl]ClO4 ([2a]ClO4) (trpy = 2,2′:6′,2′′-terpyridine, R-BIAN = bis(arylimino)acenaphthene (R = H (1a+, 3a2+), 4-OMe (1b+, 3b2+), 4-NO2 (1c+, 3c2+), BIAO = [N-(phenyl)imino]acenapthenone). The experimental (X-ray, 1H NMR, spectroelectrochemistry, EPR) and DFT/TD-DFT calculations of 1an-1cn or 2an collectively establish {RuII-BIAN0} or {RuII-BIAO0} configuration in the native state, metal-based oxidation to {RuIII-BIAN0} or {RuIII-BIAO0}, and successive electron uptake processes by the α-diimine fragment, followed by trpy and naphthalene π-system of BIAN or BIAO, respectively. The impact of the electron-withdrawing NO2 function in the BIAN moiety in 1c+ has been reflected in the five nearby reduction steps within the accessible potential limit of -2 V versus SCE, leading to a fully reduced BIAN4- state in [1c]4-. The aqua derivatives ({RuII-OH2}, 3a2+-3c2+) undergo simultaneous 2e-/2H+ transfer to the corresponding {RuIV-O} state and the catalytic current associated with the RuIV/RuV response probably implies its involvement in the electrocatalytic water oxidation. The aqua derivatives (3a2+-3c2+) are efficient and selective precatalysts in transforming a wide variety of alkenes to corresponding epoxides in the presence of PhI(OAc)2 as an oxidant in CH2Cl2 at 298 K as well as oxidation of primary, secondary, and heterocyclic alcohols with a large substrate scope with H2O2 as the stoichiometric oxidant in CH3CN at 343 K. The involvement of the {RuIV-O} intermediate as the active catalyst in both the oxidation processes has been ascertained via a sequence of experimental evidence.
- Singha Hazari, Arijit,Ray, Ritwika,Hoque, Md Asmaul,Lahiri, Goutam Kumar
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p. 8160 - 8173
(2016/08/24)
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- METHOD FOR PRODUCING EPOXY COMPOUND AND CATALYST COMPOSITION FOR EPOXIDATION REACTION
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A method of producing an epoxy compound, which comprises reacting hydrogen peroxide with a compound having a carbon-carbon double bond, in the presence of at least one of a tungsten compound and a molybdenum compound; and an onium salt comprising 20 or more carbon atoms and one or more of substituents convertible to a functional group containing an active hydrogen or a salt thereof.
- -
-
Paragraph 0491; 0492; 0493; 0494; 0495
(2015/02/18)
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- Epoxidation of strained alkenes catalysed by (1,2-dimethyl-4(1H)pyridinone-3-olate)2MnIIICl
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The mild epoxidation of strained alkenes using (DMPO)2MnCl catalyst (DMPO = 1,2-dimethyl-4(1H)-pyridinone-3-olate) in the presence of various oxidants was studied. Hydrogen peroxide and monopersulfate were found to be the best oxidants when used with imidazole in acetonitrile at 4 °C, with up to 94% conversion. Dismutation of hydrogen peroxide was also observed when used as an oxidant. The epoxidation using hydrogen peroxide or monoperoxysulfate appears to be mild and very selective for strained alkenes. A mechanism is proposed where imidazole is required for activation of the oxidant and where a detected MnV = O species is proposed as the active species. Competitive reaction between H2O2 and the substrate for the active species is proposed and homolytic vs heterolytic scissions of the OO bond of the oxidant are discussed.
- Robinson-Miller, Adam P.,Wyatt, Mark F.,Tétard, David
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p. 376 - 390
(2015/01/30)
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- Regioselective Cleavage of Electron-Rich Double Bonds in Dienes to Carbonyl Compounds with [Fe(OTf)2(mix-BPBP)] and a Combination of H2O2 and NaIO4
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A method for the regioselective transformation of dienes to carbonyl compounds has been developed. Electron-rich olefins react selectively to yield valuable aldehydes and ketones. The method is based on the catalyst [Fe(OTf)2(mix-BPBP)] with an oxidant combination of H2O2 (1.0 equiv.) and NaIO4 (1.5 equiv.); it uses mild conditions and short reaction times, and it outperforms other olefin cleavage methodologies. The combination of an Fe-based catalyst, [Fe(OTf)2(mix-BPBP)], and the oxidants H2O2 and NaIO4 can discriminate between electronically different double bonds and oxidatively cleave the electron-rich bond in dienes to yield aldehydes and ketones in a regioselective manner. The reaction requires mild conditions (0-50 C) and short reaction times (70 min).
- Spannring, Peter,Yazerski, Vital A.,Chen, Jianming,Otte, Matthias,Weckhuysen, Bert M.,Bruijnincx, Pieter C. A.,Klein Gebbink, Robertus J. M.
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p. 3462 - 3466
(2015/08/06)
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- Silica microspheres containing high density surface hydroxyl groups as efficient epoxidation catalysts
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Uniformly sized silica microspheres were synthesized by a hydrolysis-condensation method. The obtained material was etched with a mild aqueous potassium hydroxide solution for different periods of time to break their Si-O-Si bonds and increases the density of hydroxyl groups on their surfaces. The resulting materials were then used as transition metal-free catalysts for oxidation of olefins in the presence of hydrogen peroxide as a green oxidant. The materials were thoroughly characterized using various physicochemical techniques. These highly populated hydroxyl groups on the surface of silica microspheres were proven to be responsible for excellent conversion (up to 93%) and epoxide selectivity (up to 100%) for various olefins. Quantum mechanical calculations also corroborate the experimental findings. Furthermore, both experimental and theoretical studies show that tertiary silanols were present at the active sites of the catalyst surface and were responsible for olefin epoxidation.
- Chandra, Prakash,Doke, Dhananjay S.,Umbarkar, Shubhangi B.,Vanka, Kumar,Biradar, Ankush V.
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p. 21125 - 21131
(2015/03/30)
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- METHOD FOR PRODUCING EPOXY COMPOUND AND CATALYST COMPOSITION FOR EPOXIDATION REACTION
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PROBLEM TO BE SOLVED: To provide a method for producing an epoxy compound without needing a cumbersome purification process and the like where, in production of the epoxy compound, a content of heavy metals such as tungsten is extremely small, further preferably a content of a nitrogen-containing compound derived from an onium salt is small, and further more preferably a content of chlorine is small. SOLUTION: Provided is a method for producing an epoxy compound comprising epoxidizing a carbon-carbon double bond of a compound having a carbon-carbon double bond by reacting the same with hydrogen peroxide in the presence of at least either of a tungsten compound and a molybdenum compound, and an onium salt. The onium salt has four or more acyloxy groups of 1 to 4 carbon atoms and a total carbon number of the onium salt is 20 or more. COPYRIGHT: (C)2015,JPOandINPIT
- -
-
Paragraph 0214-0216
(2017/08/29)
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- Tunable Electrochemical and Catalytic Features of BIAN- and BIAO-Derived Ruthenium Complexes
-
This article deals with a class of ruthenium-BIAN-derived complexes, [RuII(tpm)(R-BIAN)Cl]ClO4 (tpm = tris(1-pyrazolyl)methane, R-BIAN = bis(arylimino)acenaphthene, R = 4-OMe ([1a]ClO4), 4-F ([1b]ClO4), 4-Cl ([1c]ClO4), 4-NO2 ([1d]ClO4)) and [RuII(tpm)(OMe-BIAN)H2O]2+ ([3a](ClO4)2). The R-BIAN framework with R = H, however, leads to the selective formation of partially hydrolyzed BIAO ([N-(phenyl)imino]acenapthenone)-derived complex [RuII(tpm)(BIAO)Cl]ClO4 ([2]ClO4). The redox-sensitive bond parameters involving -N=C-C=N- or -Ni=C-C=O of BIAN or BIAO in the crystals of representative [1a]ClO4, [3a](PF6)2, or [2]ClO4 establish its unreduced form. The chloro derivatives 1a+-1d+ and 2+ exhibit one oxidation and successive reduction processes in CH3CN within the potential limit of ±2.0 V versus SCE, and the redox potentials follow the order 1a+ + + + ≈ 2+. The electronic structural aspects of 1an-1dn and 2n (n = +2, +1, 0, -1, -2, -3) have been assessed by UV-vis and EPR spectroelectrochemistry, DFT-calculated MO compositions, and Mulliken spin density distributions in paramagnetic intermediate states which reveal metal-based (RuII → RuIII) oxidation and primarily BIAN- or BIAO-based successive reduction processes. The aqua complex 3a2+ undergoes two proton-coupled redox processes at 0.56 and 0.85 V versus SCE in phosphate buffer (pH 7) corresponding to {RuII-H2O}/{RuIII-OH} and {RuIII-OH}/{RuIV=O}, respectively. The chloro (1a+-1d+) and aqua (3a2+) derivatives are found to be equally active in functioning as efficient precatalysts toward the epoxidation of a wide variety of alkenes in the presence of PhI(OAc)2 as oxidant in CH2Cl2 at 298 K, though the analogous 2+ remains virtually inactive. The detailed experimental analysis with the representative precatalyst 1a+ suggests the involvement of the active {RuIV=O} species in the catalytic cycle, and the reaction proceeds through the radical mechanism, as also supported by the DFT calculations.
- Hazari, Arijit Singha,Das, Ankita,Ray, Ritwika,Agarwala, Hemlata,Maji, Somnath,Mobin, Shaikh M.,Lahiri, Goutam Kumar
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p. 4998 - 5012
(2015/05/27)
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- 2,2,2-Trifluoroacetophenone: An organocatalyst for an environmentally friendly epoxidation of alkenes
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A cheap, mild, fast, and environmentally friendly oxidation of olefins to the corresponding epoxides is reported using polyfluoroalkyl ketones as efficient organocatalysts. Namely, 2,2,2-trifluoroacetophenone was identified as an improved organocatalyst for the epoxidation of alkenes. Various olefins, mono-, di-, and trisubstituted, are epoxidized chemoselectively in high to quantitative yields utilizing 2-5 mol % catalyst loading and H2O 2 as the green oxidant.
- Limnios, Dimitris,Kokotos, Christoforos G.
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p. 4270 - 4276
(2014/06/09)
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- Cobalt complex in a room temperature ionic liquid: A convenient recyclable reagent for catalytic epoxidation of cyclic alkenes
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Co-catalyzed epoxidation of cyclic alkenes proceeds in ionic liquid media (1-ethyl-3-methylimidazolium hexafluorophosphate). Epoxidation of the alkenes to respective epoxides was greatly accelerated by the use of a cobalt-based catalyst in the presence of H2O2 as an oxidant. The catalyst in ionic liquid [Emim]PF6 was recycled and reused for about seven times.
- Ramakrishna, Dileep,Ramachandra Bhat, Badekai,Hanumanthappa, Suresha Kumara T.
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p. 1071 - 1074
(2015/02/05)
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- Alternative methods for production of alicyclic epoxides
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The salient and peculiar features of the oxidation of dicyclopentene and unsaturated alicyclic hydrocarbons with a medium-sized carbon ring into the corresponding epoxides have been studied. Organic hydroperoxides, aqueous hydrogen peroxide, and peracids have been used as oxidizing agents. The reactivity of the substrates in each of the oxidation processes under consideration has been estimated, and conditions providing a high epoxide yield have been chosen. The advantages and disadvantages of each process taking into account the problems of isolation of the desired product are considered. The results obtained allow the peracid method to be recommended for the synthesis of dicyclopentene epoxide as an effective and conve-nient for practical implementation. Pleiades Publishing, Ltd., 2014.
- Vereshchagina,Antonova,Abramov,Kopushkina, G. Yu.
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p. 207 - 212
(2014/07/22)
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- Electronic structure and catalytic aspects of [Ru(tpm)(bqdi)(Cl/H 2O)]n, tpm = tris(1-pyrazolyl)methane and bqdi = o-benzoquinonediimine
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The diamagnetic complexes [Ru(tpm)(bqdi)(Cl)]ClO4 ([1]ClO 4) (tpm = tris(1-pyrazolyl)methane, bqdi = o-benzoquinonediimine) and [Ru(tpm)(bqdi)(H2O)](ClO4)2 ([2](ClO 4)2) have been synthesized. The valence state-sensitive bond distances of coordinated bqdi [C-N: 1.311(5)/1.322(5) A in [1]ClO4; 1.316(7)/1.314(7) A in molecule A and 1.315(6)/1.299(7) A in molecule B of [2](ClO4)2] imply its fully oxidised quinonediimine (bqdi0) character. DFT calculations of 1+ confirm the {RuII-bqdi0} versus the antiferromagnetically coupled {RuIII-bqdi-} alternative. The 1H NMR spectra of [1]ClO4 in different solvents show variations in chemical shift positions of the NH (bqdi) and CH (tpm) proton resonances due to their different degrees of acidity in different solvents. In CH3CN/0.1 mol dm-3 Et4NClO 4, [1]ClO4 undergoes one reversible RuII ? RuIII oxidation and two reductions, the reversible first electron uptake being bqdi based (bqdi0/bqdi-). The electrogenerated paramagnetic species {RuIII-bqdi0}(1 2+) and {RuII-Q-}(1) exhibit Ru III-type (12+: = 2.211/Δg = 0.580) and radical-type (1: g = 1.988) EPR signals, respectively, as is confirmed by calculated spin densities (Ru: 0.767 in 12+, bqdi: 0.857 in 1). The aqua complex [2](ClO4)2 exhibits two one-electron oxidations at pH = 7, suggesting the formation of {RuIVO} species. The electronic spectral features of 1n (n = charge associated with the different redox states of the chloro complex: 2+, 1+, 0) in CH3CN and of 22+ in H2O have been interpreted based on the TD-DFT calculations. The application potential of the aqua complex 2 2+ as a pre-catalyst towards the epoxidation of olefins has been explored in the presence of the sacrificial oxidant PhI(OAc)2 in CH2Cl2 at 298 K, showing the desired selectivity with a wide variety of alkenes. DFT calculations based on styrene as the model substrate predict that the epoxidation reaction proceeds through a concerted transition state pathway.
- Agarwala, Hemlata,Ehret, Fabian,Chowdhury, Abhishek Dutta,Maji, Somnath,Mobin, Shaikh M.,Kaim, Wolfgang,Lahiri, Goutam Kumar
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p. 3721 - 3734
(2013/03/28)
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- Peroxometalates immobilized on magnetically recoverable catalysts for epoxidation
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Magnetically separable catalysts were prepared and employed for the epoxidation of olefins with hydrogen peroxide. In all cases the magnetic core was firstly covered with a silica layer to prevent iron ion-initiated decomposition of hydrogen peroxide. The catalytic active species, an ionic liquid-type peroxotungstate, was then immobilized either by hydrogen bonding (catalyst 1) or by covalent SiO linkage (catalyst 2). In addition to a thorough characterization by FT-IR, XRD, NMR, DRIFT, XPS, and TEM, the catalytic potential was evaluated in the epoxidation of a variety of olefins as well as allylic alcohols. Both catalysts showed essentially a constant activity after at least ten consecutive cycles. On the basis of the research above, a new type of magnetically separable catalyst was constructed by immobilization of lacunary-type phosphotungstate by hydrogen bonding between the sulfonate anion and silanol group on the surface of the core-shell magnetic nanoparticles. After the detailed characterization, the catalyst was used in the epoxidation of a variety of olefins and allylic alcohols and was found to possess high activity, selectivity towards epoxides, and a constant activity after at least ten catalytic recycles without solvent.
- Qiao, Yunxiang,Li, Huan,Hua, Li,Orzechowski, Lars,Yan, Kai,Feng, Bo,Pan, Zhenyan,Theyssen, Nils,Leitner, Walter,Hou, Zhenshan
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p. 1128 - 1138
(2013/03/13)
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- Force-reactivity property of a single monomer is sufficient to predict the micromechanical behavior of its polymer
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We demonstrate an accurate prediction of the micromechanical behavior of a single chain of cyclopropanated polybutadiene, which is governed by rapid isomerization of the cyclopropane moieties at ~1.2 nN, from the force-rate correlation of this reaction measured in a small series of increasingly strained macrocycles. The data demonstrate that a single physical quantity, force, uniquely defines the dynamics across length scales from >100 to 1 nm and that strain imposed through molecular design and that imposed by micromanipulation techniques have equivalent effects on the kinetics of a chemical reaction. This represents a new method of screening potential monomers for applications in stress-responsive materials that could also facilitate atomistic interpretations of single-molecule force experiments.
- Akbulatov, Sergey,Tian, Yancong,Boulatov, Roman
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supporting information; experimental part
p. 7620 - 7623
(2012/06/30)
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- PROCESS FOR MAKING AND USING HOF.RCN
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The invention relates to a process for making HOF.RCN and using it to oxidise organic substrates in a quick and safe way. The process comprises passing diluted fluorine through a conduit and RCN in water through another conduit into a microreactor to form HOF.RCN and reacting this with an organic substrates.
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Page/Page column 6
(2011/04/14)
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- Novel polyaniline supported cobalt catalyzed aerobic oxidation of unsaturated organic compounds
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The oxidation of organic compounds with carbon-carbon double bond with molecular oxygen under atmospheric pressure in the presence of new polyaniline supported catalyst 1 has been studied. This catalyst turned out to be efficient and selective for oxidation of some unsaturated organic compounds. Oxidation of alkenes, cycloalkenes and terpenes give corresponding epoxy derivatives, whereas organic compounds with carbon carbon double bond in benzylic position give ketones as a main product. Taylor & Francis Group, LLC.
- Pielichowski, Jan,Kowalski, Grzegorz
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experimental part
p. 105 - 111
(2011/08/03)
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- SOLID PHASE REACTION SYSTEM FOR OXIDATION
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A solid phase reaction system for oxidation of an organic compound, having high industrial value in which an organic solvent exerting a reverse influence on earth environments is not necessary, reuse of a catalyst is possible, and high yield can be attained, comprising a mixture of a powdery dispersion medium and a powder of a solid catalyst for the above-described oxidation reaction, and the above-described organic compound and aqueous hydrogen peroxide,wherein the above-described organic compound, the above-described solid catalyst and the above-described aqueous hydrogen peroxide are dispersed in the above-described mixture so that they get into contact mutually.
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Page/Page column 7
(2010/05/13)
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- Epoxidation of alkenes using HOF·MeCN by a continuous flow process
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Continuous flow methodology is described which allows the in situ generation of the highly effective oxidising agent HOF·MeCN from fluorine and wet acetonitrile and immediate reaction with alkenes to afford epoxides in high yield. The HOF·MeCN continuous flow oxidising system provides an environmentally benign process that is suitable for large scale synthesis and is atom efficient, because the only by-product is hydrogen fluoride which, in principle, could be recycled to produce fluorine by electrolysis. Crown Copyright
- McPake, Christopher B.,Murray, Christopher B.,Sandford, Graham
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experimental part
p. 1674 - 1676
(2009/09/05)
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- Microwave-assisted epoxidation of simple alkenes in the presence of hydrogen peroxide
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A novel application of microwave irradiation for the epoxidation of some simple alkenes, in which hydrogen peroxide was used as an oxidant together with sodium tungsten and phosphorous acid under phase-transfer catalytic (PTC) conditions, is described as a new environmentally benign method. In comparison with conventional heating, the microwave process is a very useful alternative for introducing of the oxirane ring into some unsaturated hydrocarbons because of reduction of the reaction time and increase in yield. Copyright Taylor & Francis, Inc.
- Bogdal,Lukasiewicz,Pielichowski,Bednarz
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p. 2973 - 2983
(2007/10/03)
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- Chemoselective epoxidation of dienes using polymer-supported manganese porphyrin catalysts
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Manganese porphyrin catalysts supported on different polymer resins were assessed in the selective epoxidation of three dienes. The recyclability of the catalysts was examined.
- Brulé, Emile,De Miguel, Yolanda R.,Hii, King Kuok
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p. 5913 - 5918
(2007/10/03)
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- Ultrasound-assisted epoxidation of olefins and α,β-unsaturated ketones over hydrotalcites using hydrogen peroxide
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An efficient ultrasound-assisted epoxidation of olefins and α,βunsaturated ketones over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile is described. This general and selective protocol is relatively fast and is applicable to a wide variety of substrates.
- Pillai, Unnikrishnan R.,Sahle-Demessie, Endalkachew,Varma, Rajender S.
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p. 2017 - 2027
(2007/10/03)
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- Microwave-expedited olefin epoxidation over hydrotalcites using hydrogen peroxide and acetonitrile
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An efficient microwave-assisted epoxidation of olefins is described over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile. This general and selective protocol is extremely fast and is applicable to a wide variety of substrates.
- Pillai, Unnikrishnan R,Sahle-Demessie, Endalkachew,Varma, Rajender S
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p. 2909 - 2911
(2007/10/03)
-
- Methyltrioxorhenium-catalyzed epoxidations in ionic liquids
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Alkenes and allylic alcohols have been epoxidized in an ambient- temperature ionic liquid for the first time using methyltrioxorhenium (MTO) and urea hydrogen peroxide; excellent conversions and selectivities for the epoxides of a wide number of substrates were observed.
- Owens, Gregory S.,Abu-Omar, Mahdi M.
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p. 1165 - 1166
(2007/10/03)
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- Transition-Metal Phthalocyanins as Catalysts for Alkene Epoxidation
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The epoxidation of alkenes catalyzed by transition-metal phthalocyanins has been studied.All the transition-metal phthalocyanins studied have catalytic properties: the manganese and iron phthalocyanins are most effective when iodosylbenzene is the oxygen donor, whereas cobalt and nickel phthalocyanins are best under phase-transfer catalysis conditions with sodium hypochlorite as the oxygen donor.The epoxidation of cis-alkenes leads to a mixture of cis- and trans-epoxides; the presence of 2,6-di-tert-butyl-p-cresol in the iron(II) phthalocyanin-catalysed reaction leads to a highly stereospecific epoxidation of cis-alkenes.The results are discussed in relation to other transition-metal-catalyzed epoxidations.
- Larsen, Erik,Joergensen, Karl Anker
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p. 259 - 263
(2007/10/02)
-
- SODIUM PERBORATE OXIDATIONS OF CYCLIC AND ACYCLIC ALKENES TO OXIRANES OR VICINAL ACETOXY ALCOHOLS
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Under different reaction conditions, sodium perborate/acetic anhydride oxidizes alkenes into oxiranes or vicinal acetoxy alcohols in good yields.
- Xie, Gaoyang,Xu, Linxiao,Hu, Jun,Ma, Shiming,Hou, Wei,Tao, Fenggang
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p. 2967 - 2968
(2007/10/02)
-
- LIQUID PHASE OXIDATION OF CYCLIC POLYOLEFINS WITH MOLECULAR OXYGEN. PART II. CIS,CIS-1,5-CYCLOOCTADIENE AUTOOXIDATION
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The autooxidation of 1,5-cyclooctadiene has been studied.Cyclooctadiene easily undergoes oxidation by molecular oxygen.Depending on the reaction procedure and the degree of conversion, polymeric or monomeric oxidated products are the dominating products with the preservation of eight-membered ring.The content of 1,2-epoxycyclooctene-5 in the product may exceed 50percent.The reaction was found to be of a free-radical character.An initiation and propagation scheme of the autooxidation is proposed.
- Giezynski, Roman,Pala, Magdalena
-
-
- Cycloaliphatic diepoxide, its preparation and its use
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1,5-Dimethyl-1,2;5,6-diepoxycyclooctane is prepared by epoxidizing 1,5-dimethylcycloocta-1,5-diene with aqueous peracetic or perpropionic acid at a temperature not exceeding 50° C. and within a pH range from 1.5 to 5.5. The diepoxide according to the invention can be cured by means of curing agents for epoxide resins to give moulded materials having valuable mechanical properties. It is also suitable for use as a reactive, latent diluent.
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- LIQUID PHASE OXIDATION OF CYCLIC POLYOLEFINS WITH MOLECULAR OXYGEN. PART I. CIS,CIS-1,5-CYCLOOCTADIENE OXIDATION REACTION PRODUCTS
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The products of liquid-phase of 1,5-cyclooctadiene with molecular oxygen were isolated and identified.
- Giezynski, Roman,Pala, Magdalena
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p. 1349 - 1355
(2007/10/02)
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