- Fe-doped H3PMo12O40 immobilized on covalent organic frameworks (Fe/PMA@COFs): A heterogeneous catalyst for the epoxidation of cyclooctene with H2O2
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Covalent organic frameworks (COFs) have arisen as one kind of devisable porous organic polymer that has attracted immense attention in catalytic applications. In this work, we prepared cost-effective imine-based COFs (COF-300, COF-LZU1 and CIN-1) via a reaction kettle operated in place of a traditional sealed Pyrex tube. Then, phosphomolybdic acid (PMA) and iron ions were immobilized on the COF supports by impregnation; the resulting frameworks were denoted as Fe/PMA@COFs (Fe/PMA@COF-LZU1, Fe/PMA@CIN-1 and Fe/PMA@COF-300). A series of characterization results demonstrated that the PMA and iron ions were uniformly dispersed on the surface/cavities of the COFs. The catalytic properties of the obtained Fe/PMA@COFs were investigated in the epoxidation of cyclooctene with H2O2 as the oxidant. The experimental results show that the Fe/PMA@CIN-1 composite can act as an efficient heterogeneous catalyst for the epoxidation of cyclooctene. The intramolecular charge transfer between the COFs and the dual sites (PMA and Fe ions), the spatial structure and the nitrogen content of the COFs played critical roles in dispersing and stabilizing the active species, which are closely connected with the activity and stability of the catalysts. A novel efficient heterogeneous catalyst for the epoxidation of olefins via a simple and cost-effective process is provided, and this experiment demonstrates the notable application prospects of the covalent organic skeleton as a catalyst support.
- Yu, Dandan,Gao, Wenxiu,Xing, Shuyu,Lian, Lili,Zhang, Hao,Wang, Xiyue,Lou, Dawei
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- Highly efficient and selective oxidation of various substrates under mild conditions using a lanthanum-containing polyoxometalate as catalyst
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A lanthanum-containing polyoxometalate (POM) of DA11[La(PW 11O39)2] (denoted as DA-La(PW 11)2; DA = Decyltrimethylammonium cation) is highly efficient and selective for oxidation of various substrates including alkenes, alkenols, sulfides, silane and alcohol with only one equiv. H2O 2 as oxidant at 25 °C, and the POM catalyst can be easily recovered and reused for ten times without obvious decrease of catalytic activity and the yields for catalyst recovery are all above 95%. The epoxidation of cis-cyclooctene proceeds efficiently in 98% yield with only 0.08 mol% of DA-La(PW11)2, and the turnover number (TON) can reach as high as 1200 at 25 °C.
- Zhao, Shen,Jia, Yueqing,Song, Yu-Fei
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- Catalytic epoxidation of cyclic alkenes with air over CoOx/zeolite heterogeneous catalysts
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The supported CoOx/zeolites have been prepared and applied for the epoxidation of cyclic alkenes with air. The catalysts are characterized by powder X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis) and scanning electron microscope (SEM). Among these CoOx/zeolite catalysts, 2.4% CoOx/Y exhibits the best catalytic activity for the epoxidation of cis-cyclooctene with 61.2 mol% conversion and 98.8 mol% selectivity of epoxide. Some factors such as the kind of zeolites, the oxidants, the solvents, the Co contents, the reaction temperature and time play important roles in controlling the epoxidation. The recyclable stability of the 2.4% CoOx/Y catalyst is confirmed.
- Ma,Lu,Wei,Zhao,Zhan,Zhou,Xia
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- Selective Catalytic Olefin Epoxidation with MnII-Exchanged MOF-5
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Partial substitution of ZnII by MnII in Zn4O(terephthalate)3 (MOF-5) leads to a distorted all-oxygen ligand field supporting a single MnII site, whose structure was confirmed by Mn K-edge X-ray absorption spectroscopy. The MnII ion at the MOF-5 node engages in redox chemistry with a variety of oxidants. With tBuSO2PhIO, it produces a putative MnIV-oxo intermediate, which upon further reaction with adventitious hydrogen is trapped as a MnIII-OH species. Most intriguingly, the intermediacy of the high-spin MnIV-oxo species is likely responsible for catalytic activity of the MnII-MOF-5 precatalyst, which in the presence of tBuSO2PhIO catalyzes oxygen atom transfer reactivity to form epoxides from cyclic alkenes with >99% selectivity. These results demonstrate that MOF secondary building units serve as competent platforms for accessing terminal high-valent metal-oxo species that consequently engage in catalytic oxygen atom transfer chemistry owing to the relatively weak ligand fields provided by the SBU.
- Stubbs, Amanda W.,Braglia, Luca,Borfecchia, Elisa,Meyer, Randall J.,Román-Leshkov, Yuriy,Lamberti, Carlo,Dincǎ, Mircea
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- Epoxidation of alkenes through oxygen activation over a bifunctional CuO/Al2O3 catalyst
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The epoxidation of alkenes was carried out over a CuO/Al2O 3 catalyst using cumene as an oxygen carrier, through a one-pot reaction, giving high conversion and selectivity with different substrates. Trans-β-methylstyrene gave the corresponding epoxide in 95% yield after 3 h. The Royal Society of Chemistry 2013.
- Scotti, Nicola,Ravasio, Nicoletta,Zaccheria, Federica,Psaro, Rinaldo,Evangelisti, Claudio
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- Epoxidation of cycloolefins with hydrogen peroxide in the presence of heteropoly acids combined with phase transfer catalyst
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Oxidation of cycloolefins (cyclohexene, cyclooctene, and cyclododecene) with a 30% solution of hydrogen peroxide at 65°C in the presence of heteropoly acids (HPA) H3PW12-xMoxO 40 (x = 0-12), which are precursors of active peroxo complexes, and phase transfer catalysts Q+Cl-, where Q+ is the quaternary ammonium cation containing C4-C18 alkyl groups or [C5H5NC16H33] +, was studied. The catalytic activity decreases in the HPA series: H3PW12O40 > H3PW 9Mo3O40 > H3PW6Mo 6O40 > H3PW3Mo9O 40 > H3PMo12O40. The state of the H3PW12O40-H2O2 system was studied using UV, IR, and 31P NMR spectroscopies with variation of the [H2O2]:[HPA] ratio from 2 to 200 during cyclohexene epoxidation. Despite different catalytic precursors, the reaction proceeds through the same peroxo complex.
- Timofeeva,Pai,Tolstikov,Kustova,Selivanova,Berdnikova,Brylyakov,Shangina,Utkin
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- Lipase catalysed oxidations in a sugar-derived natural deep eutectic solvent
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Chemoenzymatic oxidations involving the CAL-B/H2O2 system was developed in a sugar derived Natural Deep Eutectic Solvent (NaDES) composed by a mixture of glucose, fructose and sucrose. Good to excellent conversions of substrates like cyclooctene, limonene, oleic acid and stilbene to their corresponding epoxides, cyclohexanone to its corresponding lactone and 2-phenylacetophenone to its corresponding ester, demonstrate the viability of the sugar NaDES as a reaction medium for epoxidation and Baeyer-Villiger oxidation.
- Vagnoni, Martina,Samorì, Chiara,Pirini, Daniele,Vasquez De Paz, Maria Katrina,Gidey, Dawit Gebremichael,Galletti, Paola
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- Fast-synthesis and catalytic property of heterogeneous Co-MOF catalysts for the epoxidation of α-pinene with air
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In the past decades, many methods have been developed for synthesizing MOFs, including solvothermal synthesis, mechanical synthesis, electrochemical synthesis, and microwave synthesis. Based on the existing research, a method is proposed for synthesizing Co-MOF by rapidly rotating hydrothermal crystallization, which largely shortens the crystallization time of Co-MOF. When the rotation speed was 150 rpm, only 2 h of crystallization time was needed to synthesize Co-MOF-150-2 with high crystallinity and stability. The optimal Co-MOF-150-2 manifested remarkable activity and selectivity for the epoxidation of α-pinene under mild conditions. The catalytic conversion of α-pinene reached the highest over the Co-MOF-150-2 catalyst, in which the conversion of α-pinene was 99.5% and the yield of 2,3-epoxypinane was 95.7%. The Co-MOF materials synthesized by the rotary method also had excellent stability and highly catalytic activity in recycling experiments. This journal is
- Zhang, Haifu,He, Jie,Lu, Xinhuan,Yang, Lu,Wang, Chenlong,Yue, Fanfan,Zhou, Dan,Xia, Qinghua
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p. 17413 - 17421
(2020/11/02)
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- Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
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Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
- Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
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supporting information
p. 14201 - 14205
(2019/10/02)
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- Modular Polyoxometalate–Layered Double Hydroxides as Efficient Heterogeneous Sulfoxidation and Epoxidation Catalysts
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The selective sulfoxidation of sulfides and the epoxidation of olefins are two types of important organic reactions, and the corresponding products of sulfoxides, sulfones and epoxides are used widely as raw materials in industrial processes. The fabrication of one efficient catalyst for both reactions remains a challenging task. We report the preparation of a highly efficient heterogeneous catalyst Mg3Al-ILs-La(PW11)2 using an exfoliation/assembly approach. The catalyst was characterised by FT-IR spectroscopy, XRD, thermogravimetric and differential thermal analysis, BET measurements, X-ray photoelectron spectroscopy, 29Si cross-polarisation magic-angle spinning NMR spectroscopy, 27Al magic-angle spinning NMR spectroscopy, SEM, high-resolution TEM, and energy-dispersive X-ray spectroscopy. The designed catalyst showed a high efficiency and selectivity for the sulfoxidation of sulfides and the epoxidation of olefins under mild conditions at a production rate of 208 and 31 mmol g?1 h?1, respectively. Moreover, Mg3Al-ILs-La(PW11)2 can be recycled and re-used at least five times without a clear decrease of its catalytic activity. The scaled-up experiments revealed that the catalyst retained its efficiency and robustness, which demonstrates the great potential of the catalyst for industrial applications.
- Li, Tengfei,Zhang, Wei,Chen, Wei,Miras, Haralampos N.,Song, Yu-Fei
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p. 188 - 197
(2017/11/28)
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- An Organotin Vanadate with Sodalite Topology and Catalytic Versatility in Oxidative Transformations
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The new coordination polymer formulated as [Et3SnVO3] (1) has been synthesized and shown by a combined single-crystal and synchrotron powder X-ray diffraction structural analysis, supported by solid-state NMR, to possess a three-dimensional network structure with the sodalite topology, formed by tetravanadate polyanions, [V4O12]4?, that are linked by Et3Sn+ spacers. The catalytic versatility of compound 1 for liquid phase organic reactions was demonstrated by applying it for the epoxidation of olefins, the oxidative dehydrogenation of alcohols, and the oxidation of benzyl alcohol to benzaldehyde and benzoic acid, using tert-butyl hydroperoxide (TBHP) as oxidant. Compound 1 acts a solid reservoir for soluble, catalytically active species, which promote high selectivities to the epoxide and carbonyl (aldehyde/ketone/acid) products. The epoxidation activity compares favorably with those reported for other organotin molybdate, tungstate and vanadate coordination polymers, and is superior to that displayed by the starting materials used for its synthesis (Et3SnBr and NH4VO3) and the metavanadate NBu4VO3.
- Gomes, Ana C.,Antunes, Margarida M.,Abrantes, Marta,Valente, Anabela A.,Paz, Filipe A. Almeida,Gon?alves, Isabel S.,Pillinger, Martyn
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p. 3481 - 3489
(2018/08/03)
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- High-yield synthesis and catalytic response of chainlike hybrid materials of the [(MoO3): M(2,2′-bipyridine)n] family
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The one-dimensional organic-inorganic hybrid material [MoO3(2,2′-bipy)] (1) (2,2′-bipy = 2,2′-bipyridine) has been used as a starting material to prepare the bipy-deficient phases [Mo2O6(2,2′-bipy)] (2) and [Mo3O9(2,2′-bipy)2] (3) in excellent yields. The hybrid 2 was obtained by a solid-state thermal treatment of 1 (300 °C, 10 min) while 3 was obtained by a hydrothermal treatment of 1 (160 °C, 6 d). A study was performed to compare the catalytic properties of 1-3 in the epoxidation of cis-cyclooctene at 55 °C with tert-butylhydroperoxide (TBHP) or aqueous H2O2 as oxidant. In all cases Cy was converted to cyclooctene oxide (CyO) with 100% selectivity, and Cy conversions increased in the order 1 2O2 (cosolvent CH3CN). The catalytic reactions occurred in homogeneous phase with active species formed in situ from 1-3. All three hybrids react with aqueous H2O2 to give the catalytically active oxodiperoxo complex [MoO(O2)2(2,2′-bipy)]. The 2:1 hybrid 2 was further examined for the epoxidation of other cyclic and linear non-functionalised olefins with TBHP, namely cyclododecene, 1-octene and trans-2-octene, and the biomass-derived olefins dl-limonene, α-pinene and methyl oleate.
- Bruno, Sofia M.,Nogueira, Lucie S.,Gomes, Ana C.,Valente, Anabela A.,Gon?alves, Isabel S.,Pillinger, Martyn
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p. 16483 - 16492
(2018/10/24)
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- Cobalt immobilized on hydroxyapatite as a low-cost and highly effective heterogeneous catalyst for alkenes epoxidation under mild conditions
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Transition metal Co immobilized on hydroxyapatite with a loading of 0.05 wt% (denoted 0.05 wt% Co/HAP) could catalyze partial oxidation of cyclic alkenes, aromatic alkenes and aliphatic alkenes to yield epoxide products with excellent selectivity at 30 °C with O2 and iso-butyraldehyde as co-oxidant. The TOF value was as high as 6261 h?1 for epoxidation of cyclohexene. In addition, the prepared 0.05 wt% Co/HAP catalyst can be re-used at least 6 times without significant loss of catalytic activity and selectivity.
- Mekrattanachai, Pagasukon,Cao, Changyan,Li, Zhaohua,Li, Huining,Song, Weiguo
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p. 37303 - 37306
(2018/11/26)
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- Triazolyl, Imidazolyl, and Carboxylic Acid Moieties in the Design of Molybdenum Trioxide Hybrids: Photophysical and Catalytic Behavior
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Three organic ligands bearing 1,2,4-triazolyl donor moieties, (S)-4-(1-phenylpropyl)-1,2,4-triazole (trethbz), 4-(1,2,4-triazol-4-yl)benzoic acid (trPhCO2H), and 3-(1H-imidazol-4-yl)-2-(1,2,4-triazol-4-yl)propionic acid (trhis), were prepared to evaluate their coordination behavior in the development of molybdenum(VI) oxide organic hybrids. Four compounds, [Mo2O6(trethbz)2]·H2O (1), [Mo4O12(trPhCO2H)2]·0.5H2O (2a), [Mo4O12(trPhCO2H)2]·H2O (2b), and [Mo8O25(trhis)2(trhisH)2]·2H2O (3), were synthesized and characterized. The monofunctional tr-ligand resulted in the formation of a zigzag chain [Mo2O6(trethbz)2] built up from cis-{MoO4N2} octahedra united through common μ2-O vertices. Employing the heterodonor ligand with tr/-CO2H functions afforded either layer or ribbon structures of corner- or edge-sharing {MoO5N} polyhedra (2a or 2b) stapled by tr-links in axial positions, whereas -CO2H groups remained uncoordinated. The presence of the im-heterocycle as an extra function in trhis facilitated formation of zwitterionic molecules with a protonated imidazolium group (imH+) and a negatively charged -CO2- group, whereas the tr-fragment was left neutral. Under the acidic hydrothermal conditions used, the organic ligand binds to molybdenum atoms either through [N-N]-tr or through both [N-N]-tr and μ2-CO2- units, which occur in protonated bidentate or zwitterionic tetradentate forms (trhisH+ and trhis, respectively). This leads to a new zigzag subtopological motif (3) of negatively charged polyoxomolybdate {Mo8O25}n2n- consisting of corner- and edge-sharing cis-{MoO4N2} and {MoO6} octahedra, while the tetradentate zwitterrionic trhis species connect these chains into a 2D net. Electronic spectra of the compounds showed optical gaps consistent with semiconducting behavior. The compounds were investigated as epoxidation catalysts via the model reactions of achiral and prochiral olefins (cis-cyclooctene and trans-β-methylstyrene) with tert-butylhydroperoxide. The best-performing catalyst (1) was explored for the epoxidation of other olefins, including biomass-derived methyl oleate, methyl linoleate, and prochiral dl-limonene.
- Lysenko, Andrey B.,Senchyk, Ganna A.,Domasevitch, Konstantin V.,Kobalz, Merten,Krautscheid, Harald,Cichos, Jakub,Karbowiak, Miroslaw,Neves, Patrícia,Valente, Anabela A.,Gon?alves, Isabel S.
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p. 4380 - 4394
(2017/04/26)
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- One-pot synthesis of molybdenum oxide nanoparticles encapsulated in hollow silica spheres: An efficient and reusable catalyst for epoxidation of olefins
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We report a one-pot synthesis of MoOx NPs encapsulated inside hollow silica spheres (MoOx@HSS) which act as an efficient and reusable heterogeneous catalyst in the epoxidation of olefins. A yolk-shell nanostructured MoOx-SiO2 composite, consisting of core MoOx NPs and permeable porous hollow silica spheres, was fabricated via a self-assembly approach using poly(acrylic acid) as an organic template and dodecyltrimethoxysilane as a pore-directing agent. On the basis of comprehensive structural analyses by FE-SEM, TEM, elemental mapping, N2 physisorption and Mo K-edge XAFS, we show that MoOx NPs of ca. 5.8 nm diameter are encapsulated within hollow silica spheres having randomly arranged mesopores of ca. 2.1 nm diameter, while addition of an excess amount of the pore-directing agent leads to a deformation of the yolk-shell nanostructures. The obtained yolk-shell nanostructured MoOx-SiO2 composite exhibits prominent reusability with a modest catalytic activity in the liquid-phase epoxidation of olefins with TBHP owing to the presence of the protective silica shell, making it an effective heterogeneous catalyst for the transformation of olefins into their corresponding epoxides.
- Kuwahara, Yasutaka,Furuichi, Naoyuki,Seki, Hiroyuki,Yamashita, Hiromi
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p. 18518 - 18526
(2017/09/22)
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- Aerobic epoxidation catalysed by transition metal substituted polyfluorooxometalates
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First row transition metal substituted polyfluorooxmetalates with quasi Wells-Dawson structures and a nitro terminal ligand, [NaH2M(NO2)W17F6O55]q-, were used as catalysts for the aerobic epoxidation of cyclic alkenes. The Cu(NO2) analog combined the best traits of conversion and selectivity. Some C-C bond cleavage was also observed and cis isomers reacted preferentially without stereochemical inversion indicating an oxygen atom to double bond concerted reaction.
- Bugnola, Marco,Neumann, Ronny
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p. 14534 - 14537
(2016/09/28)
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- Superparamagnetic Core–Shell Metal–Organic Framework Fe3O4/Cu3(btc)2 Microspheres and Their Catalytic Activity in the Aerobic Oxidation of Alcohols and Olefins
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Core–shell structured Fe3O4/Cu3(btc)2 (btc = 1,3,5-benzenetricarboxylate) microspheres have been successfully synthesized by coating the metal–organic frameworks on poly(acrylic acid) (PAA) functionalized Fe3O4 microspheres by the layer-by-layer assembly method. The MOF composite exhibited excellent catalytic activity in the aerobic oxidation of alcohols and the epoxidation of olefins due to the porosity of MOFs and large amount of readily accessible Cu2+. Furthermore, the catalyst could be easily segregated from the catalytic system by using an external magnetic field due to its magnetic properties. The heterogeneous catalyst displayed good reusability and broad reagent scope in the aerobic oxidation of alcohols and epoxidation of olefins.
- Li, Jie,Gao, Hongyi,Tan, Li,Luan, Yi,Yang, Mu
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p. 4906 - 4912
(2016/10/26)
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- Easily recoverable titanosilicate zeolite beads with hierarchical porosity: Preparation and application as oxidation catalysts
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Titanosilicate zeolite beads with hierarchical porosity and 0.2-0.5 mm diameter (HPB-TS-1) have been synthesized from a titanosilicate solution, employing a porous anion-exchange resin as shape- and structure-directing template. The characterization results showed the existence of crystalline TS-1 nanoparticles and of a network of connected large meso/macropores in the interior of the beads. These bead materials are active and selective heterogeneous catalysts for two classes of industrially relevant oxidation reactions: the hydroxylation of phenol and the epoxidation of alkenes. In both cases, a green oxidant such as hydrogen peroxide was utilized. HPB-TS-1 beads displayed high activity in the hydroxylation of phenol, due to their crystalline TS-1 structure with isolated tetrahedral Ti species. In the epoxidation of cyclohexene, HPB-TS-1 gave conversion comparable to that over a benchmark catalyst such as Ti-MCM-41, but more than double yield and selectivity of the target product, cyclohexene oxide. HPB-TS-1 was also active and selective in the epoxidation of other bulky alkenes, i.e., cis-cyclooctene and trans, trans, cis-1,5,9-cyclododecatriene. The catalytic performance of HPB-TS-1 stems from the presence of crystalline TS-1 nanodomains, which are accessible through a network of meso/macropores within the beads. Notably, the bead format of these catalysts causes their spontaneous settling upon cessation of the agitation, thus enabling their straightforward separation from the reaction mixture. The HPB-TS-1 catalysts could be efficiently recycled in the hydroxylation of phenol with aqueous H2O2 via a calcination approach.
- Cheng, Wenjing,Jiang, Yanqiu,Xu, Xianzhu,Wang, Yan,Lin, Kaifeng,Pescarmona, Paolo P.
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p. 139 - 148
(2015/12/01)
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- Co(ii) complexes loaded into metal-organic frameworks as efficient heterogeneous catalysts for aerobic epoxidation of olefins
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A series of efficient cobalt(ii)-anchored Cr-MOF (Cr-MIL-101-NH2) catalysts, such as Co(ii)@Cr-MIL-101-Sal, Co(ii)@Cr-MIL-101-P2I and Co(ii)@Cr-MIL-101-P3I, have been successfully synthesized by one-pot modification of the terminal amino group with salicylaldehyde, pyridine-2-aldehyde or pyridine-3-aldehyde and anchoring of Co(ii) ions into the mesoporous Cr-MOF supports. The Co(ii)@Cr-MIL-101-P2I catalyst exhibited high catalytic performance for epoxidation of olefins with air as an oxidant due to the nitrogen atom in the pyridine ring as a strong electron-withdrawing substituent, high dispersion of Co(ii) species and high surface area for sufficient contact between the substrate and active sites. The strong coordination interaction between the Co(ii) ions and chelating groups in the Co(ii)@Cr-MIL-101-P2I catalyst guaranteed the excellent recycling performance. Furthermore, the synthesized Co(ii)@Cr-MIL-101-P2I catalyst realized its general applicability towards various olefins, such as cyclic olefins, tri-substituted olefins, aliphatic olefins and aromatic olefins.
- Wang, Jingjing,Yang, Mu,Dong, Wenjun,Jin, Zhaokui,Tang, Jia,Fan, Shuang,Lu, Yunfeng,Wang, Ge
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p. 161 - 168
(2015/12/31)
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- A method for continuous preparation of epoxy rings-dodecane
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The invention relates to a method of preparing 1,2-epoxycyclododecane through epoxidation cyclododecene by utilization of tert-butyl hydroperoxide (TBHP). According to the method, addition of the TBHP is controlled under the existence of a catalyst, and the system concentration of an oxidant is controlled by adopting a batch addition manner to reduce generation of side reactions, thus ensuring complete conversion of the cyclododecene and achieving high selectivity of the main product 1,2-epoxycyclododecane. The excess TBHP is converted by adding another low-molecular-weight olefin to cogenerate a low-molecular-weight epoxy compound, thus ensuring safety of subsequent separation and facilitating process amplification.
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Paragraph 0050-0053
(2017/06/02)
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- Efficient epoxidation of cyclododecene and dodecene catalysed by polybenzimidazole supported Mo(VI) complex
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A polybenzimidazole supported Mo(VI) complex (PBI.Mo) has been prepared and characterised. The catalytic activity of PBI.Mo for the epoxidation of cyclododecene and dodecene with tert-butyl hydroperoxide (TBHP) as an oxidant has been studied under different reaction conditions in a batch reactor. The stability of heterogeneous Mo(VI) catalyst was evaluated by recycling a sample in batch reaction using conditions that will form the basis of continuous process. The leaching of Mo species from PBI.Mo has been investigated by isolating any residue from reaction supernatant solutions following the removal of the heterogeneous catalyst, then using the residues as potential catalyst in epoxidation reactions. The batch epoxidation experimental data provided useful information for conducting continuous epoxidation in a reactive distillation column (RDC).
- Mbeleck, Rene,Mohammed, Misbahu Ladan,Ambroziak, Krzysztof,Sherrington, David C.,Saha, Basudeb
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p. 287 - 293
(2015/09/15)
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- Nanoscaled copper metal-organic framework (MOF) based on carboxylate ligands as an efficient heterogeneous catalyst for aerobic epoxidation of olefins and oxidation of benzylic and allylic alcohols
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Aerobic epoxidation of olefins at a mild reaction temperature has been carried out by using nanomorphology of [Cu3(BTC)2 ] (BTC = 1,3,5-benzenetricarboxylate) as a high-performance catalyst through a simple synthetic strategy. An aromatic carboxylate ligand was employed to furnish a heterogeneous copper catalyst and also serves as the ligand for enhanced catalytic activities in the catalytic reaction. The utilization of a copper metal-organic framework catalyst was further extended to the aerobic oxidation of aromatic alcohols. The shape and size selectivity of the catalyst in olefin epoxidation and alcohol oxidation was investigated. Furthermore, the as-synthesized copper catalyst can be easily recovered and reused several times without leaching of active species or significant loss of activity.
- Qi, Yue,Luan, Yi,Yu, Jie,Peng, Xiong,Wang, Ge
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p. 1589 - 1597
(2015/01/30)
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- Selective Oxidation with Aqueous Hydrogen Peroxide by [PO4{WO(O2)2}4]3- Supported on Zinc-Modified Tin Dioxide
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We prepared supported phosphorus-containing tetranuclear peroxotungstate ([PO4{WO(O2)2}4]3-, denoted by PW4) catalysts by using zinc-modified SnO2 supports with different zinc contents [PW4-Zn(x)/SnO2, in which x denotes the zinc content (wt%)]. The supported catalysts, in particular PW4-Zn(0.8)/SnO2, could act as efficient and reusable heterogeneous catalysts for selective oxidation with aqueous H2O2 as the terminal oxidant. The catalytic performance of PW4-Zn(0.8)/SnO2 was much superior to those of the corresponding homogeneous analogue THA3PW4 (THA=tetra-n-hexylammonium) and the previously reported tungstate-based heterogeneous catalysts such as our W-Zn/SnO2. In the presence of PW4-Zn(0.8)/SnO2, various types of organic substrates such as alkenes, amines, silanes, and sulfides could be converted into the corresponding oxygenated products in high to excellent yields by using near-stoichiometric amounts of H2O2 with respect to the substrates (typically 1.2 equiv.). The PW4 species interacting with highly dispersed Zn2+ species on SnO2 likely plays an important role in the present oxidation.
- Nojima, Susumu,Kamata, Keigo,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 1097 - 1104
(2015/04/14)
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- Imparting magnetic functionality to iron-based MIL-101 via facile Fe3O4 nanoparticle encapsulation: an efficient and recoverable catalyst for aerobic oxidation
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The development of sustainable, easily synthesizable and highly efficient catalysts is a fundamental goal of catalysis science. In this work, highly superparamagnetic nanoparticles (Fe3O4 NPs) were prepared through a modified co-precipitation method and embedded into a Fe-MIL-101 metal-organic-framework through a facile encapsulation strategy. The catalytic activity of Fe3O4/Fe-MIL-101 was investigated in the aerobic oxidation of alcohols and epoxidation of olefines. High yields (up to quantitative conversion) were observed for both reactions under mild conditions. Furthermore, the magnetic NP/MOF catalysts could be easily recovered and recycled; even after usage in eight consecutive reaction batches, no significant loss of catalytic efficiency was observed. This class of catalysts is promising for green and practical large-scale industrial applications.
- Jin, Zhaokui,Luan, Yi,Yang, Mu,Tang, Jia,Wang, Jingjing,Gao, Hongyi,Lu, Yunfeng,Wang, Ge
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p. 78962 - 78970
(2015/10/05)
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- Crystal Structure and Catalytic Behavior in Olefin Epoxidation of a One-Dimensional Tungsten Oxide/Bipyridine Hybrid
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The tungsten oxide/2,2′-bipyridine hybrid material [WO3(2,2′-bpy)]·nH2O (n = 1-2) (1) has been prepared in near quantitative yield by the reaction of H2WO4, 2,2′-bpy, and H2O in the mole ratio of ca. 1:2:700 at 160°C for 98 h in a rotating Teflon-lined digestion bomb. The solid-state structure of 1 was solved and refined through Rietveld analysis of high-resolution synchrotron X-ray diffraction data collected for the microcrystalline powder. The material, crystallizing in the orthorhombic space group Iba2, is composed of a one-dimensional organic-inorganic hybrid polymer, ∞1[WO3(2,2′-bpy)], topologically identical to that found in the previously reported anhydrous phases [MO3(2,2′-bpy)] (M = Mo, W). While in the latter the N,N′-chelated 2,2′-bpy ligands of adjacent corner-shared {MO4N2} octahedra are positioned on the same side of the 1D chain, in 1 the 2,2′-bpy ligands alternate above and below the chain. The catalytic behavior of compound 1 for the epoxidation of cis-cyclooctene was compared with that for several other tungsten- or molybdenum-based (pre)catalysts, including the hybrid polymer [MoO3(2,2′-bpy)]. While the latter exhibits superior performance when tert-butyl hydroperoxide (TBHP) is used as the oxidant, compound 1 is superior when aqueous hydrogen peroxide is used, allowing near-quantitative conversion of the olefin to the epoxide. With H2O2, compounds 1 and [MoO3(2,2′-bpy)] act as sources of soluble active species, namely, the oxodiperoxo complex [MO(O2)2(2,2′-bpy)], which is formed in situ. Compounds 1 and [WO(O2)2(2,2′-bpy)] (2) were further tested in the epoxidation of cyclododecene, trans-2-octene, 1-octene, (R)-limonene, and styrene. The structure of 2 was determined by single-crystal X-ray diffraction and found to be isotypical with the molybdenum analogue.
- Amarante, Tatiana R.,Antunes, Margarida M.,Valente, Anabela A.,Paz, Filipe A. Almeida,Pillinger, Martyn,Gon?alves, Isabel S.
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p. 9690 - 9703
(2015/11/03)
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- Formation of persulphate from sodium sulphite and molecular oxygen catalysed by H5PV2Mo10O40-aerobic epoxidation and hydrolysis
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The H5PV2Mo10O40 polyoxometalate catalysed the electron transfer oxidation of sulphite to yield a sulphite radical, SO3- that upon addition of O2 yielded a peroxosulphate species efficient for the H5PV2Mo10O40 catalysed epoxidation of alkenes. The acidic polyoxometalate further catalysed hydrolysis of the epoxide to give vicinal diols in high yields. This journal is
- Rubinstein, Amir,Carmeli, Raanan,Neumann, Ronny
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p. 13247 - 13249
(2015/05/20)
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- Hierarchical PS/PANI nanostructure supported Cu(ii) complexes: Facile synthesis and study of catalytic applications in aerobic oxidation
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Hierarchical heterogeneous copper catalysts were prepared by immobilization of a homogeneous copper(ii) complex on the surface of polystyrene/polyaniline (PS/PANI) microspheres with oriented PANI nanofibers. EDX element maps and XPS spectra indicated that Cu2+ ions strongly coordinated with PANI imine. PS/PANI@Cu(OSO2CF3)2 exhibited excellent catalytic activity for selective aerobic oxidation of alcohols and highly efficient aerobic epoxidation of alkenes under mild conditions. The supported copper(ii) catalyst maintained high levels of conversion and selectivity in these reactions after six cycles and showed good stability. This journal is
- Yu, Jie,Luan, Yi,Qi, Yue,Hou, Junying,Dong, Wenjun,Yang, Mu,Wang, Ge
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p. 55028 - 55035
(2015/02/19)
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- METHOD FOR PRODUCING AMIDE COMPOUND
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The present invention relates to a method for producing a high purity, high quality amide compound, particularly, lactam. A first embodiment of the present invention is characterized in that an amount of each of a halide, an aldehyde compound, an alcohol compound and a nitrile compound contained in a solution recycled into an oxime-forming step is controlled to an amount of 0.4 mol % or less based on the ketone as a starting material. A second embodiment of the present invention is characterized in that one or more compounds selected from the group consisting of a ketone, an oxime and an amide compound are purified by hydrogenation and/or crystallization for eliminating impurities containing a double bond. A third embodiment of the present invention is characterized in that a content of impurities having a cyclic bridge structure is controlled by using a cycloalkanone purified by recrystallization.
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Page/Page column 25-26
(2013/02/28)
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- Heterogeneous catalytic epoxidation of olefin over a hydrothermally synthesized 3D phosphate bridged copper(II) framework
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A 3D copper phosphate, [Cu2(PO4)(OH)] n (1), has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction analysis. In [Cu2(PO4)(OH)] n, there are two types of copper centers having distorted trigonal bipyramidal geometry and distorted octahedral geometry that are connected by the μ2-bridging of each phosphate oxygen ultimately forming a η8-PO4 bridged 3D network. The compound exhibited excellent catalytic performance in olefin epoxidation. Epoxidation of styrene and substituted styrenes, as well as bulky olefins like cycloalkenes and long-chain alkenes, is efficiently catalyzed by [Cu2(PO 4)(OH)] n using tert-butylhydroperoxide in acetonitrile. The results obtained in the heterogeneous catalytic reactions show that the olefins are converted to the respective epoxides in good yield with high selectivity. [Cu2(PO4)(OH)] n was catalytically more active and selective in comparison to simple copper(II) phosphate salt in heterogeneous medium. The catalyst can be recycled and reused several times without significant loss of activity.
- Saha, Debraj,Maity, Tanmoy,Sen, Rupam
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p. 2444 - 2454
(2013/08/23)
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- Tris(pyrazolyl)methane molybdenum tricarbonyl complexes as catalyst precursors for olefin epoxidation
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The molybdenum tricarbonyl complexes [Mo(CO)3(HC(3,5-Me 2pz)3)] (1) and [Mo(CO)3(HC(pz)3)] (2) (HC(3,5-Me2pz)3 = tris(3,5-dimethyl-1-pyrazolyl) methane, HC(pz)3 = tris(1-pyrazolyl)methane) were obtained in good yields by the microwave-assisted reaction of Mo(CO)6 with the respective organic ligand. Complete oxidative decarbonylation of 1 and 2 was achieved by reaction with excess tert-butylhydroperoxide (TBHP) in 1,2-dichloroethane at 55 °C. For complex 1, the (μ2-oxo) bis[dioxomolybdenum(VI)] hexamolybdate of composition [{MoO2(HC(3,5- Me2pz)3)}2(μ2-O)][Mo 6O19] (3) was obtained in good yield, and its structure was determined by single crystal X-ray diffraction. The compound (4) obtained by oxidative decarbonylation of 2 was not unambiguously identified, but may be chemically analogous to 3. Compounds 1-4 were examined for the first time as homogeneous (pre)catalysts for the epoxidation of olefins with TBHP, using different types of cosolvents at 55 °C. During the catalytic reactions 1 and 2 transform in situ into 3 and 4, respectively, and the latter two are fairly stable catalysts. Catalytic tests and characterization studies of the recovered catalysts were carried out in an attempt to understand the kinetic differences observed between the compounds prepared in situ during the catalytic reaction and those prepared prior to the catalytic reaction, from the same precursor complex.
- Gomes, Ana C.,Neves, Patrícia,Figueiredo, Sónia,Fernandes, José A.,Valente, Anabela A.,Almeida Paz, Filipe A.,Pillinger, Martyn,Lopes, André D.,Gon?alves, Isabel S.
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- Lanthanide carboxylate frameworks: Efficient heterogeneous catalytic system for epoxidation of olefins
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Two lanthanide-based three dimensional metal-organic frameworks (MOF) viz. [Nd(HCOO)3]n (1) and [Pr(HCOO)3]n (2) have been synthesized and characterized. Both the compounds have similar structure. In this study we have demonstrated that the compounds are highly efficient in catalyzing epoxidation of various cyclic and linear olefinic substrates. MOF compounds are stable and recyclable under the reaction conditions. Notably, MOF systems are remarkably more active and selective than the corresponding lanthanide oxide in epoxidation reaction of olefins.
- Sen, Rupam,Saha, Debraj,Koner, Subratanath
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experimental part
p. 124 - 130
(2012/04/10)
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- A highly active protonated tetranuclear peroxotungstate for oxidation with hydrogen peroxide
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Acid assists: The reaction of [{WO(O2)2} 2(μ-O)]2- with 0.5 equivalents of HNO3 gave a tetranuclear peroxotungstate (1; see picture) that has a dramatically enhanced activity for the epoxidation of cyclooctene with H2O2 compared to various peroxotungstates. The 1-catalyzed system was applicable to the selective oxidation of various kinds of substrates with 1.0-1.5 equivalents of H2O2. Copyright
- Ishimoto, Ryo,Kamata, Keigo,Mizuno, Noritaka
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experimental part
p. 4662 - 4665
(2012/06/30)
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- Structural and dynamical aspects of alkylammonium salts of a silicodecatungstate as heterogeneous epoxidation catalysts
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The structural and dynamical aspects of alkylammonium salts of a silicodecatungstate [(CH3)4N]4[γ-SiW 10O34(H2O)2] [C1], [(n-C 3H7)4N]4[γ-SiW 10O34(H2O)2] [C3], [(n-C 4H9)4N]4[γ-SiW 10O34(H2O)2] [C4], and [(n-C 5H11)4N]4[γ-SiW 10O34(H2O)2] [C5] were investigated. The results of sorption isotherms, XRD analyses, and solid-state NMR spectroscopy show that facile sorption of solvent molecules, flexibility of structures, and high mobility of alkylammonium cations are crucial to the uniform distribution of reactant and oxidant molecules throughout the bulk solid, which are related to the high catalytic activities for epoxidation of alkenes.
- Uchida, Sayaka,Kamata, Keigo,Ogasawara, Yoshiyuki,Fujita, Megumi,Mizuno, Noritaka
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supporting information; scheme or table
p. 9979 - 9983
(2012/09/10)
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- Multilayer structured MFI-type titanosilicate: Synthesis and catalytic properties in selective epoxidation of bulky molecules
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A lamellar titanosilicate (LTS-1) was hydrothermally synthesized by employing a bifunctional surfactant as the structure-directing agent (SDA). Highly crystalline LTS-1 was obtained at an optimal SDA/Si molar ratio of 0.04. As-synthesized LTS-1 possessed a multilayer structure, which was constructed from a collection of 2-nm zeolite nanosheets and interlayer SDA molecules. Removing the intercalated organic species induced irregular layer stacking to a certain extent, leading to intracrystal mesopores of ca. 3.2 nm in diameter. The catalytic performance of LTS-1 was investigated in the epoxidation of various bulky alkenes with tert-butyl hydroperoxide, cumene hydroperoxide, or aqueous H2O2. LTS-1 was more active than conventional titanosilicates for reactions involving bulky alkenes and oxidants, and it was immune to Ti leaching and irreversible deactivation.
- Wang, Jianggan,Xu, Le,Zhang, Kun,Peng, Honggen,Wu, Haihong,Jiang, Jin-Gang,Liu, Yueming,Wu, Peng
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scheme or table
p. 16 - 23
(2012/05/04)
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- Epoxidation of olefins using a dichlorodioxomolybdenum(VI)-pyridylimine complex as catalyst
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The ligand N-(n-propyl)-2-pyridylmethanimine (pyim) and an immobilized analogue of this ligand (pyim-MTS) were prepared by the condensation reaction of 2-pyridinecarboxaldehyde with either n-propylamine or 3-aminopropyl groups covalently attached to a micelle-templated silica (MTS). Free and immobilized dioxomolybdenum(VI) complexes of the type MoO2Cl2(L 1) (L1 = pyim (1), pyim-MTS) were then prepared by treatment of the organic ligand or ligand-silica with the solvent adduct MoO2Cl2(THF)2. MoO2Cl 2(pyim) (1) is a highly active catalyst for the epoxidation of olefins (cyclooctene (Cy), cyclododecene, 1-octene, trans-2-octene, R-(+)-limonene) at 55 °C using tert-butylhydroperoxide (TBHP) as the oxidant under solvent-free conditions, giving the corresponding epoxides as the only reaction products. A turnover frequency of 1855 mol molMo -1 h-1 was measured for the epoxidation of Cy, and the epoxide (CyO) was formed quantitatively within 4.5 h. The MTS-supported complex was less active, and exhibited temperature-dependent leaching of active species. As an alternative approach to facilitating catalyst recycling, complex 1 was investigated with the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate as solvent. The 1/IL phase could be reused, giving ca. 95% CyO yield in each run.
- Balula, Salete S.,Bruno, Sofia M.,Gomes, Ana C.,Valente, Anabela A.,Pillinger, Martyn,Gonalves, Isabel S.,MacQuarrie, Duncan J.,Clark, James H.
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experimental part
p. 234 - 239
(2012/07/03)
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- Efficient heterogeneous epoxidation of alkenes by a supported tungsten oxide catalyst
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Oxidation optimization: A combination of tungsten and zinc oxides on a SnO2 support (W-Zn/SnO2) is a heterogeneous and reusable solid catalyst for selective oxidation with aqueous H2O2. With it, various substrates, such as alkenes, amines, silanes, and sulfides, were oxidized into the corresponding products in high yields (see scheme). The catalyst can be reused several times without an appreciable loss in catalytic performance. Copyright
- Kamata, Keigo,Yonehara, Koji,Sumida, Yasutaka,Hirata, Kazuhisa,Nojima, Susumu,Mizuno, Noritaka
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supporting information; scheme or table
p. 12062 - 12066
(2012/02/03)
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- CO2 activation and promotional effect in the oxidation of cyclic olefins over mesoporous carbon nitrides
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Mesoporous carbon nitrides (MCN) were prepared by a nano-casting method using mesoporous silica as a template with different carbon and nitrogen sources like melamine only (MS-MCN), urea-formaldehyde (UF-MCN) and melamine-glyoxal (MG-MCN). These mesoporous carbon nitride materials possess nitrogen moieties which behave like a CO2-philic surface facilitating oxidation of cyclic olefins by molecular oxygen in the co-presence of CO2 below supercritical conditions. The co-presence of CO2 augmented the conversions of cyclic olefins at low pressures of CO2, depicting a promotional effect. Approaches towards quantification of promotional effects and insights into the promotional aspects have been studied.
- Ansari, Mohd Bismillah,Min, Byung-Hoon,Mo, Yong-Hwan,Park, Sang-Eon
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experimental part
p. 1416 - 1421
(2011/08/03)
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- Polyoxometalate-based hybrid mesostructured catalysts for green epoxidation of olefins
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Novel hybrid polyoxometalates (POM) of α-H3PW 12O40·nHMPA and α-H3PMo 12O40·nHMPA composed of α-H 3PW12O40 and H3PMo 12O40 heteropoly acides (HPAs) and hexamethylphosphoramide (HMPA) organic substrate has been synthesized and purified. SBA-15 mesoporous silica is synthesized, using P123 surfactant via hydrothermal method, and functionalized with aminopropyl functional groups via grafting method. The synthesized mesostructured supports are used for intercalation of the hybrid POMs. The parent Keggin HPAs are also immobilized within the supports to perform closer and more efficient investigation. After characterization, effect of functional groups on immobilization pattern and quality is taken into consideration. The mesostructured organic-inorganic hybrid materials are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic absorption, and FT-IR analysis. The newly designed hybrid catalysts are investigated for heterogeneous epoxidation of olefins. Effects of temperature, oxidant, and catalyst amount are studied and the reaction conditions are optimized. An interpretation of the differences in the catalytic activity of the precursors is put forward and their catalytic activity is compared with their HPA counterparts. Furthermore, effects of functionalization on catalyst activity, stability, and reusability are taken into consideration. Results reveal that the designed mesostructured POM based hybrid catalysts can selectively and efficiently epoxidize olefins in presence of hydrogen peroxide as oxidant. The catalysts are shown to be heterogeneous and reusable without significant loss of activity in the proceeding rounds.
- Karimi,Mahjoub,Harati
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experimental part
p. 1 - 9
(2011/10/30)
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- Highly efficient activation of molecular oxygen with nanoporous metalloporphyrin frameworks in heterogeneous systems
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A nanoporous metalloporphyrin framework exhibits high activity in the activation of molecular oxygen and excellent catalytic activity in the aerobic epoxidation of olefins, with high conversion, outstanding selectivity, and broad substrate applicability. The porous framework is reusable and allows large-scale transformation. These catalytic features are correlated with the structural characteristics of the porous framework and mark a breakthrough for this classic reaction. Copyright
- Chen, Long,Yang, Yong,Guo, Zhaoqi,Jiang, Donglin
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experimental part
p. 3149 - 3154
(2012/06/01)
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- Titanosilicate beads with hierarchical porosity: Synthesis and application as epoxidation catalysts
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Porous titanosilicate beads with a diameter of 0.5-1.5a mm (TiSil-HPB-60) were synthesized from a preformed titanosilicate solution with a porous anion-exchange resin as template. The bead format of this material enables its straightforward separation from the reaction mixture in its application as a liquid-phase heterogeneous catalyst. The material displays hierarchical porosity (micro/mesopores) and incipient TS-1 structure building units. The titanium species are predominantly located in tetrahedral framework positions. TiSil-HPB-60 is a highly active catalyst for the epoxidation of cyclohexene with t-butyl hydroperoxide (TBHP) and aqueous H2O2. With both oxidants, TiSil-HPB-60 gave higher epoxide yields than Ti-MCM-41 and TS-1. The improved catalytic performance of TiSil-HPB-60 is mainly ascribed to the large mesopores favoring the diffusion of reagents and products to and from the titanium active sites. The epoxide yield and selectivity could be further improved by silylation of the titanosilicate beads. Importantly, TiSil-HPB-60 is a stable catalyst immune to titanium leaching, and can be easily recovered and reused in successive catalytic cycles without significant loss of activity. Moreover, TiSil-HPB-60 is active and selective in the epoxidation of a wide range of bulky alkenes. Beads for catalysis: Titanosilicate beads with hierarchical porosity (see figure) displayed improved catalytic behavior in the epoxidation of cyclohexene with tert-butyl hydroperoxide and H2O 2 relative to TS-1 and Ti-MCM-41. The bead format of the material enables a straightforward separation of the catalyst from the reaction solutions. Copyright
- Lin, Kaifeng,Lebedev, Oleg I.,Vana Tendeloo, Gustaaf,Jacobs, Pierre A.,Pescarmona, Paolo P.
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experimental part
p. 13509 - 13518
(2011/03/17)
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- Epoxidation of alkenes with hydrogen peroxide catalyzed by selenium-containing dinuclear peroxotungstate and kinetic, spectroscopic, and theoretical investigation of the mechanism
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The dinuclear peroxotungstate with a SeO42- ligand, (TBA)2[SeO4{WO(O2)2}2] (I; TBA=[(n-C4Hg)4N]+), could act as an efficient homogeneous catalyst for the selective oxidation of various kinds of organic substances such as olefins, alcohols, and amines with H 2O2 as the sole oxidant. The turnover frequency (TOF) was as high as 210 h-1 for the epoxidation of cyclohexene catalyzed by I with H2O2. The catalyst was easily recovered and reused with maintenance of the catalytic performance. The SeO42- ligand in I played an important role in controlling the Lewis acidity of the peroxotungstates, which significantly affects their electrophilic oxygen-transfer reactivity. Several kinetic and spectroscopic results showed that the present catalytic epoxidation included the following two steps: (I) formation of the subsequent peroxo species [SeWmOn] o- (II; m=1 and 2) by the reaction of I with an olefin and (ii) regeneration of I by the reaction of Il with H2O2. Compound I was the dominant species under steady-state turnover conditions. The reaction rate for the catalytic epoxidation showed a first-order dependence on the concentrations of olefin and I and a zero-order dependence on the concentration of H2O2. The rate of the stoichiometric epoxidation with I agreed well with that of the catalytic epoxidation with H2O2 by I. All of these kinetic and spectroscopic results indicate that oxygen transfer from I to the C=C double bond is the rate-determining step. The computational studies support that the oxygen-transfer step is the rate-determining step.
- Kamata, Keigo,Lshimoto, Ryo,Hirano, Tomohisa,Kuzuya, Shinjiro,Uehara, Kazuhiro,Mizuno, Noritaka
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experimental part
p. 2471 - 2478
(2010/05/15)
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- Cyclopentadienyl molybdenum dicarbonyl η3-allyl complexes as catalyst precursors for olefin epoxidation. Crystal structures of Cp′Mo(CO)2(η3-C3H5) (Cp′ = η5-C5H4Me, η5-C5Me5)
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The complexes Cp′Mo(CO)2(η3-C 3H5) [Cp′ = η5-C5H 5 (1), η5-C5H4Me (2), η5-C5Me5 (3)] have been prepared, structurally characterised by X-ray diffraction (2, 3), and tested as catalyst precursors for the epoxidation of olefins at 55 °C. Complex 1 gave a turnover frequency (TOF) of 310 mol molMo-1 h-1 in the epoxidation of cis-cyclooctene with tert-butylhydroperoxide (TBHP, in decane) as oxidant, and 1,2-epoxycyclooctane was obtained quantitatively within 6 h. A similar result was obtained for complex 2, while the TOF for 3 was about one order of magnitude lower, suggesting a possible activity dependence on the ring substituents. For 1 the use of 1,2-dichloroethane as solvent increased the initial reaction rate to 361 mol molMo-1 h-1, with no decrease in epoxide selectivity. Under these conditions the reaction rates for other olefins increased in the order 1-octene 2O2 as oxidants, which gave epoxide yields of 99% and 27% at 24 h, respectively. The possibility of facilitating catalyst recycling by using ionic liquids as solvents was investigated.
- Neves, Patrícia,Pereira, Cláudia C.L.,Almeida Paz, Filipe A.,Gago, Sandra,Pillinger, Martyn,Silva, Carlos M.,Valente, Anabela A.,Rom?o, Carlos C.,Gonalves, Isabel S.
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experimental part
p. 2311 - 2319
(2010/10/19)
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- A flexible nonporous heterogeneous catalyst for size-selective oxidation through a bottom-up approach
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Size does matter: The nonporous tetra-n-butylammonium salt of silicodecatungstate, synthesized through a bottom-up approach, heterogeneously catalyzes the size-selective oxidation of various organic compounds, including olefins, sulfides, and organosilanes, with aqueous H2O2 in ethyl acetate. The catalyst can be easily separated by filtration and reused several times with retention of high catalytic activity. Copyright
- Mizuno, Noritaka,Uchida, Sayaka,Kamata, Keigo,Ishimoto, Ryo,Nojima, Susumu,Yonehara, Koji,Sumida, Yasutaka
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supporting information; experimental part
p. 9972 - 9976
(2011/03/18)
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- Oxidation of alkenes with hydrogen peroxide, catalyzed by boron trifluoride. Synthesis of vicinal methoxyalkanols
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In oxidation of alkenes with the BF3-H2O2 system, boron trifluoride induces transfer of available oxygen from hydrogen peroxide, accompanied by the formation of epoxides. The oxidation in methanol occurs as a one-pot two-step process involving epoxidation of the C=C bond followed by opening of the oxirane ring, with the formation of methoxyalkanols.
- Terent'ev,Boyarinova,Nikishin
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p. 592 - 596
(2008/09/20)
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- Synthesis of novel nanotubular mesoporous nickel phosphates with high performance in epoxidation
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Two novel mesoporous nickel phosphates (NiPO-1 and NiPO-2) with nanotubular structures were developed in the presence of cationic surfactant and different bases by a sol-gel method. The mesostructures of NiPO-1 and NiPO-2 are composed of nanotubes of different lengths, which are arranged by a less-ordered lamellar symmetry as synthesized. ICP elemental analysis revealed that they are different compounds. The Ni/P molar ratios of NiPO-1 and NiPO-2 are 1.57 and 1.20, respectively. Both materials possess a relatively high BET surface area (205-292 m2 g-1) and good thermal stability up to 673 K. It is found that these novel materials exhibited high activity (>50%) and high selectivity to epoxide (95.6% and 99.0%) in the epoxidation of cyclododecene with H2O2 as oxidant.
- Yu, Jing,Wang, Anjie,Tan, Juan,Li, Xiang,Van Bokhoven, Jeroen Anton,Hu, Yongkong
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experimental part
p. 3601 - 3607
(2010/03/01)
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- Olefin epoxidation with hydrogen peroxide catalyzed by lacunary polyoxometalate [γ-SiW10O34(H2O) 2]4-
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The tetra-n-butylammonium (TBA) salt of the divacant Keggin-type polyoxometalate [TBA]4[γ-SiW10O34-(H 2O)2] (I) catalyzes the oxygen-transfer reactions of olefins, allylic alcohols, and sulfides with 30% aqueous hydrogen peroxide. The negative Hammett ρ+ (-0.99) for the competitive oxidation of p-substituted styrenes and the low value of (nucleophilic oxidation)/(total oxidation), Xso = 0.04, for I-catalyzed oxidation of thianthrene 5-oxide (SSO) reveals that a strongly electrophilic oxidant species is formed on I. The preferential formation of trans-spoxide during epoxidation of 3-methyl-1-cyclohexene demonstrates the steric constraints of the active site of I. The I-catalyzed epoxidation proceeds with an induction period that disappears upon treatment of I with hydrogen peroxide. 29Si and 183W NMR spectroscopy and CSI mass spectrometry show that reaction of I with excess hydrogen peroxide leads to fast formation of a diperoxo species, [TBA]4[γ-SiW10O32(O2) 2] (II), with retention of a γ-Keggin type structure. Whereas the isolated compound II is inactive for stoichiometric epoxidation of cyclooctene, epoxidation with II does proceed in the presence of hydrogen peroxide. The reaction of II with hydrogen peroxide would form a reactive species (III), and this step corresponds to the induction period observed in the catalytic epoxidation. The steric and electronic characters of III are the same as those for the catalytic epoxidation by I. Kinetic, spectroscopic, and mechanistic investigations show that the present epoxidation proceeds via III.
- Kamata, Keigo,Kotani, Miyuki,Yamaguchi, Kazuya,Hikichi, Shiro,Mizuno, Noritaka
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p. 639 - 648
(2007/10/03)
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- Macrocyclic thiiranes
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The present invention provides a compound having the formulae: wherein Z is CH2, CH=CH or CHSCH (thiirane), provided that if two or more Z are CH=CH they are not conjugated and wherein n is selected so that the total number of carbon atoms is from 8 to 20. Mixtures of these compounds, methods for their preparation, their use as perfume materials for application to a variety of substrates and their use in flavoring and in articles of manufacture is also provided.
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Page/Page column 2; 4
(2008/06/13)
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- Dendritic phosphonates and the in situ assembly of polyperoxophosphotungstates: Synthesis and catalytic epoxidation of alkenes with hydrogen peroxide
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First and second-generation rigid dendrimers based on polyphenylated tetrahedral adamantane cores with four or sixteen peripheral phosphonate moieties, PD1 and PD2, respectively, were synthesized and characterized. Further reaction of the dendritic phosphonates with tungstic acid in the presence of hydrogen peroxide led to the stepwise in situ formation of mono- and dinuclear phosphoperoxotungstates. These assemblies were effective catalysts for the epoxidation of alkenes in an aqueous acetonitrile solvent.
- Vasylyev, Maxym V.,Astruc, Didier,Neumann, Ronny
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- Liquid-phase epoxidation of alkenes using molecular oxygen catalyzed by vanadium cation-exchanged montmorillonite
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Vanadium cation-exchanged montmorillonite can efficiently catalyze the selective epoxidation of various alkenes and the oxygenation of adamantane using molecular oxygen as a sole oxidant. Copyright
- Mitsudome, Takato,Nosaka, Naoya,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 1626 - 1627
(2007/10/03)
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- Direct aerobic epoxidation of alkenes catalyzed by metal nanoparticles stabilized by the H5PV2Mo10O40 polyoxometalate
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Ag and Ru nanoparticles stabilized by H5PV2MO 10O40, prepared by a sequence of redox reactions and supported on α-alumina, were effective catalysts for the direct aerobic epoxidation of alkenes in the liquid phase. The Royal Society of Chemistry 2005.
- Maayan, Galia,Neumann, Ronny
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p. 4595 - 4597
(2007/10/03)
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