- Catalyst Systems Based on a Metal Halide and a Quaternary Ammonium Salt in the 1,2-Epoxycyclopentane Carboxylation Reaction
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Abstract: Results of a study of 1,2-epoxycyclopentane carboxylation to cyclopentene carbonate (CPC) in the presence of various catalyst systems have been described. It has been found that the reaction occurs most efficiently in the presence of cobalt (nickel) chloride (bromide) hydrate and a quaternary ammonium salt (TEAB, TBAB). It has been recommended that CPC should be synthesized under a CO2 pressure of no less than 3.5 MPa at a temperature of 140–150°С without any solvent or in the medium of a solvent, such as target CPC, DMF, or N-MP, at a 1,2-epoxycyclopentane weight fraction in the feed mixture of no less than 25%. These conditions provide the formation of CPC with a selectivity of 97–99% and almost complete epoxide conversion within 2–4 h. It has been shown that the developed catalyst system can be recycled.
- Taranenko, G. Yu.,Rybina,Srednev,Meshechkina,Tarasov
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- Basic ionic liquid supported on mesoporous SBA-15: An efficient heterogeneous catalyst for epoxidation of olefins with H2O 2 as oxidant
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Basic ionic liquid functionalized mesoporous silica SBA-15 was prepared and characterized by XRD, N2 adsorption-desorption, FT-IR and TEM. The catalyst demonstrated to be an efficient heterogeneous catalyst for olefin epoxidation using H2O2 as oxidant. The catalyst could be recycled at least five times without appreciable loss of catalytic activity.
- Yuan, Chengyuan,Huang, Zhiwei,Chen, Jing
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- A porous Mn(v) coordination framework with PtS topology: Assessment of the influence of a terminal nitride on CO2 sorption
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A new coordination framework material, [Zn{MnN(CN)4(H 2O)}]·2H2O·MeOH, has been characterised crystallographically and the effect of a terminal nitride on the N2, H2 and CO2 sorption capacities of the material assessed through porosimetery measurements and DRIFTS.
- Murphy, Michael J.,D'Alessandro, Deanna M.,Kepert, Cameron J.
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- Efficiency of phase-transfer catalysis in cyclopentene epoxidation with hydrogen peroxide
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The effect of the structure and amount of the phase-transfer catalyst (quaternary ammonium salts) and the solvent effect on cyclopentene oxidation with an aqueous hydrogen peroxide solution in the liquid-liquid two-phase system was studied. The phase-tran
- Meshechkina,Mel'Nik,Rybina,Srednev,Shevchuk
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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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- 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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- Molybdenum oxide supported on hydroxyapatite-encapsulated γ-Fe 2O3: A novel magnetically recyclable catalyst for olefin epoxidation
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Hydroxyapatite-encapsulated magnetic γ-Fe2O3 (HAP-γ-Fe2O3) was synthesized and used as catalyst support. Molybdenum oxide nanoparticles were supported on HAP-γ-Fe 2O3 by incipient wetness impregnation (MoO x/HAP-γ-Fe2O3). High-resolution transmission electron microscopy characterization demonstrated the formation of γ-Fe2O3 nanocrystallites with a mean diameter of 1-3 nm within the HAP matrix. The molybdenum oxide dispersed on the surface of HAP-γ-Fe2O3 showed good catalytic activities for the epoxidation of various olefins with tert-butyl hydroperoxide as oxidant. The magnetism of MoOx/HAP-γ-Fe2O3 provided a convenient route for the separation of the catalyst from the reaction mixture by a magnet. The catalyst was recycled at least five times without appreciable loss of catalytic activity.
- Yuan, Chengyuan,Zhang, Yan,Chen, Jing
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- A Na2WO4/H2WO4-based highly efficient biphasic catalyst towards alkene epoxidation, using dihydrogen peroxide as oxidant
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The tungsten-containing biphasic catalytic system [Na2WO 4/H2WO4/PTR/chloroacetic acid] effectively epoxidizes alkenes with 50% H2O2 as terminal oxidant, under organic solvent-free conditions. The catalytic process is proposed to proceed via a dinuclear tungsten peroxo species with coordinated chloroacetic acid, as suggested by ESI-MS measurements. The catalytic system is suggested to involve tungsten-peroxo and/or peracetic acid type of epoxidation catalyzed by the tungsten(VI) in the presence of an organic acid and H2O 2. The reaction conditions employed for various alkenes for epoxidation are mild compared to the earlier studies and result in high product selectivity and conversion rate.
- Maheswari, Palanisamy Uma,De Hoog, Paul,Hage, Ronald,Gamez, Patrick,Reedijk, Jan
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- Synthesis, characterization and catalytic activities of nonheme manganese(III) complexes: Preferential formation of cis olefin oxide owing to steric hindrance
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Three mononuclear nonheme MnIII(salophen) complexes, 1a-1c, with tetradentate ligands containing two deprotonated phenolates ([(X2-tert-butyl-salophen)Mn(OAc)(H2O)] (tert-butyl-salophen = N,N′-bis(6-di-tert-butylsalicylidene)-1,2-phenylenediaminato, 1a for X = Cl, 1b for X = H, and 1c for X = CH3)) were synthesized and characterized using 1H NMR, 13C NMR, elemental analysis and ESI-Mass spectrometry. These Mn(III) complexes were used to efficiently catalyze the epoxidation reactions of diverse aliphatic, aromatic and terminal alkenes to form the corresponding epoxides with MCPBA (m-chloroperoxybenzoic acid) as an oxidant under mild conditions. Notably, catalysts 1a-1c preferably react with the cis-alkene because of the steric hindrance between the reactive intermediate MnIII-OOC(O)R and the trans-type substrate. A Hammett study and product analysis using PPAA (peroxyphenylacetic acid) as a mechanistic indicator suggested that the peracid reacted with the Mn(III) complex to generate the MnIII-OOC(O)R intermediate, which underwent both homolysis and heterolysis to form MnIV=O or MnV=O. The reactive MnV=O might participate in the alkene epoxidation with good stereospecificity, whereas the MnIV=O species might trigger radical-type oxidation to produce non-stereospecific by-products, such as ketones and aldehyde. On the other hand, MnIII-OOC(O)R (2) could oxidize the reactive cyclohexene to the epoxide, whereas it was unable to epoxidize the poorly reactive 1-octene.
- Kim, Cheal,Lee, Jiyoung,Moon, Sungjin,Park, Soyoung
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- Rhenium-containing compound(PyHReO4): synthesis, characterization and catalytic application in olefin epoxidation and baeyer-villiger oxidation
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A novel compound based on catalytic functional metal rhenium, pyridinium perrhenate(PyHReO4) was synthesized and characterized. The pyridinium perrhenate was used as catalyst in two types of reactions. One is the epoxidation of cyclooctene, the other is the Baeyer-Villiger oxidation of cyclic ketones to lactones. The effects of catalyst, oxidant, solvent, reaction time and temperature were investigated, which confirmed the optimum reaction conditions of the catalyst system. Both types of catalytic reactions exhibit high yields and high selectivity. Graphical abstract: The synthesized novel compound based on catalytic functional metal rhenium, pyridinium perrhenate(PyHReO4) exhibit excellent catalytic activity. The system with PyHReO4 as a catalyst provided an effective, easy separation, mild and convenient method in two different types of reactions(One is the epoxidation of cyclooctene, the other is the Baeyer-Villiger oxidation of 2-adamantanone). [Figure not available: see fulltext.]
- Dong, Yingnan,Li, Yucai,Song, Shiwei,Wang, Gang,Wang, Han,Wang, Jian,Wang, Shuaijie,Zhang, Dong,Zhao, Yan
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- Nonheme manganese(III) complexes for various olefin epoxidation: Synthesis, characterization and catalytic activity
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Three mononuclear imine-based non-heme manganese(III) complexes with tetradentate ligands which have two deprotonated phenolate moieties, ([(X2saloph)Mn(OAc)(H2O)], 1a for X = Cl, 1b for X = H, and 1c for X = CH3, saloph = N,N-o-phenylenebis(salicylidenaminato)), were synthesized and characterized by 1H NMR, 13C NMR, ESI-Mass and elemental analysis. MnIII complexes catalysed efficiently various olefin epoxidation reactions with meta-chloroperbenzoic acid (MCPBA) under the mild condition. MnIII complexes 1a and 1c with the electron-withdrawing group -Cl and electron-donating group –CH3 showed little substituent effect on the epoxidation reactions. Product analysis, Hammett study and competition experiments with cis- and trans-2-octene suggested that MnIV = O, MnV = O, and MnIII-OOC(O)R species might be key oxidants in the epoxidation reaction under this catalytic system. In addition, the use of PPAA as a mechanistic probe demonstrated that Mn-acylperoxo intermediate (MnIII-OOC(O)R) 2 generated from the reaction of peracid with manganese complexes underwent both the heterolysis and the homolysis to produce MnV = O (3) or MnIV = O species (4). Moreover, the MnIII-OOC(O)R 2 species could react directly with the easy-to-oxidize substrate to give epoxide, whereas the species 2 might not be competent to the difficult-to-oxidize substrate for the epoxidation reaction.
- Lee, Sojeong,Park, Soyoung,Lee, Myoung Mi,Lee, Jiyoung,Kim, Cheal
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- Aldehyde-catalyzed epoxidation of unactivated alkenes with aqueous hydrogen peroxide
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The organocatalytic epoxidation of unactivated alkenes using aqueous hydrogen peroxide provides various indispensable products and intermediates in a sustainable manner. While formyl functionalities typically undergo irreversible oxidations when activating an oxidant, an atropisomeric two-axis aldehyde capable of catalytic turnover was identified for high-yielding epoxidations of cyclic and acyclic alkenes. The relative configuration of the stereogenic axes of the catalyst and the resulting proximity of the aldehyde and backbone residues resulted in high catalytic efficiencies. Mechanistic studies support a non-radical alkene oxidation by an aldehyde-derived dioxirane intermediate generated from hydrogen peroxide through the Payne and Criegee intermediates.
- Kokotos, Christoforos G.,Kokotou, Maroula G.,Lotter, Dominik,Sparr, Christof,Triandafillidi, Ierasia
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p. 10191 - 10196
(2021/08/12)
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- Proton Switch in the Secondary Coordination Sphere to Control Catalytic Events at the Metal Center: Biomimetic Oxo Transfer Chemistry of Nickel Amidate Complex
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High-valent metal-oxo species are key intermediates for the oxygen atom transfer step in the catalytic cycles of many metalloenzymes. While the redox-active metal centers of such enzymes are typically supported by anionic amino acid side chains or porphyrin rings, peptide backbones might function as strong electron-donating ligands to stabilize high oxidation states. To test the feasibility of this idea in synthetic settings, we have prepared a nickel(II) complex of new amido multidentate ligand. The mononuclear nickel complex of this N5 ligand catalyzes epoxidation reactions of a wide range of olefins by using mCPBA as a terminal oxidant. Notably, a remarkably high catalytic efficiency and selectivity were observed for terminal olefin substrates. We found that protonation of the secondary coordination sphere serves as the entry point to the catalytic cycle, in which high-valent nickel species is subsequently formed to carry out oxo-transfer reactions. A conceptually parallel process might allow metalloenzymes to control the catalytic cycle in the primary coordination sphere by using proton switch in the secondary coordination sphere.
- Kim, Soohyung,Jeong, Ha Young,Kim, Seonghan,Kim, Hongsik,Lee, Sojeong,Cho, Jaeheung,Kim, Cheal,Lee, Dongwhan
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supporting information
p. 4700 - 4708
(2021/02/12)
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- Cu(ii)Cl2containing bispyridine-based porous organic polymer support preparedviaalkyne-azide cycloaddition as a heterogeneous catalyst for oxidation of various olefins
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A new type of porous organic polymer (POP) based heterogeneous catalystCu-POPwas prepared by immobilizing Cu(ii)Cl2into bpy containing POP preparedviaalkyne-azide cycloaddition. This new catalyst showed efficient catalytic activities and outstanding reusability. Remarkably, one batch ofCu-POPwas continuously used for all olefins without losing its activity by simply washing.
- Choi, Hye Min,Lee, Suk Joong,Yoon, Jongho
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supporting information
p. 9149 - 9152
(2020/06/17)
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- Biochar as supporting material for heterogeneous Mn(II) catalysts: Efficient olefins epoxidation with H2O2
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A novel type of hybrid catalytic materials [MnII-L?BC] has been developed using biochar (BC) as support material for covalent grafting of a MnII Schiff-base catalyst (MnII-L). The hybrid [MnII-L?BC] materials have been evaluated for an important catalytic process, epoxidation of olefins using H2O2 as oxidant. A number of different substrates were used, with cyclohexene achieving the highest yields. When compared to the non-grafted, homogeneous MnII-L, the hybrid catalysts [MnII-L?BC] show a significant enhancement of the catalytic efficiency i.e. as documented by the increase of Turnover Numbers (TONs) (826 for [MnII-L-SS550ox] and 822 for [MnII-L-SW550ox]) and Turnover Frequencies (TOFs) (551 h?1 for [MnII-L-SS550ox] and 411 h?1 for [MnII-L-SW550ox]). The interfacial catalytic mechanism and the role of the BC support have been analyzed by Raman and Electron Paramagnetic Resonance spectroscopies. Based on these data we discuss a mechanism where the high efficiency of the hybrid materials involves the biochar carbon layers acting as promoters of the substrate and products kinetics. To a broader context, this work exemplifies that biochar-based hybrid materials are potent for oxidative catalysis technologies.
- Borges Regitano, Jussara,Deligiannakis, Yiannis,Gemenetzi, Aikaterini,Louloudi, Maria,Mavrogiorgou, Alexandra,Pierri, Leticia
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- Controlling the Morphology and Titanium Coordination States of TS-1 Zeolites by Crystal Growth Modifier
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Developing an effective strategy to synthesize perfect titanosilicate TS-1 zeolite crystals with desirable morphologies, enriched isolated framework Ti species, and thus enhanced catalytic oxidation properties is a pervasive challenge in zeolite crystal engineering. We here used an amino acid l-carnitine as a crystal growth modifier and ethanol as a cosolvent to regulate the morphologies and the Ti coordination states of TS-1 zeolites. During the hydrothermal crystallization process, the introduced l-carnitine can not only tailor the anisotropic growth rates of zeolite crystals but also induce the formation of uniformly distributed framework Ti species through building a suitable chemical interaction with the Ti precursor species. Condition optimizations could afford the generation of perfect hexagonal plate TS-1 crystals and elongated platelet TS-1 crystals enriched in tetrahedral framework Ti sites (TiO4) or mononuclear octahedrally coordinated Ti species (TiO6). Both samples showed significant improvement in catalytic activity for the H2O2-mediated epoxidation of alkenes. In particular, the elongated platelet TS-1 enriched in "TiO6"species afforded the highest activity in 1-hexene epoxidation, with a turnover frequency (TOF) of up to 131 h-1, which is approximately twice as high as that of the conventional TS-1 zeolite (TOF: 65 h-1) and even higher than those of the literature-reported TiO6-containting TS-1 catalysts derived from the hydrothermal post-treatment of TS-1 zeolites. This work demonstrates that the morphologies and the titanium coordination states of TS-1 zeolites can be effectively tuned by directly introducing suitable crystal growth modifiers, thus providing new opportunities for developing highly efficient titanosilicate zeolite catalysts for important catalytic applications.
- Chang, Xinyu,Chen, Ziyi,Hu, Dianwen,Jia, Mingjun,Li, Yingying,Song, Xiaojing,Yang, Xiaotong,Yu, Jihong,Zhang, Hao,Zhang, Peng,Zhang, Qiang,Zhang, Tianjun
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supporting information
p. 13201 - 13210
(2020/10/02)
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- Mn(III)-Porphyrin Containing Heterogeneous Catalyst based on Microporous Polymeric Constituents as a New Class of Catalyst Support
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Mn(III)-porphyrin containing #heterogeneous catalyst based on microporous polymeric constituents as a new class of #catalyst support from Korea University and Seoul National University of Science and Technology.
- Yi, Jigyoung,Jeong, Ha Young,Shin, Dae Yong,Kim, Cheal,Lee, Suk Joong
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p. 3974 - 3977
(2018/09/25)
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- Non-Heme Iron Catalysts for Olefin Epoxidation: Conformationally Rigid Aryl–Aryl Junction To Support Amine/Imine Multidentate Ligands
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Atom-transfer chemistry represents an important class of reactions catalyzed by metalloenzymes. As a functional mimic of non-heme iron enzymes that deliver oxygen atoms to olefins, we have designed monoiron complexes supported by new N-donor chelates. These ligands take advantage of heme-like conformational rigidity of the π-conjugated molecular backbone, and synthetic flexibility of tethering non-heme donor groups for additional steric and electronic control. Iron complexes generated in situ can be used to carry out catalytic epoxidation of a wide range of olefin substrates by using mCPBA as a terminal oxidant. The fate of initial iron-peracid adduct and the involvement of iron-oxo species in this process were investigated further by mechanistic probes and isotope exchange studies. Our findings suggest that anilidopyridyl-derived [N,N]-bidentate motif could serve as a versatile structural platform to build non-heme ligands for catalytic oxidation chemistry.
- Park, Hyunchang,Ahn, Hye Mi,Jeong, Ha Young,Kim, Cheal,Lee, Dongwhan
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supporting information
p. 8632 - 8638
(2018/05/30)
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- Highly efficient oxidation of cyclopentene catalyzed by magnetically recoverable Ca–Co ferrite spinels with high solvent selectivity
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The calcium doped CoFe2O4 spinels CaxCo1?xFe2O4 (x = 0, 0.1, 0.3, 0.5 and 0.7) were prepared by simple sol–gel auto-combustion method. The samples were characterized by X-ray diffractometry, Raman spectrometry, scanning and transmission electron microscopy, N2-physisorption and inductive coupled plasma-atomic emission spectroscopy. The samples have shown prominent activities in oxidation of cyclopentene using 30% hydrogen peroxide as oxidant. When compared to the pristine CoFe2O4, the Ca-doped ones were more efficient having a conversion ranging from 72.1% to 100% and a H2O2 utilization efficiency range of 80.0–84.7%. When the calcium content was 0.3 and above, the cyclopentene was quantitatively converted to cyclopentenone at 60 °C for 8 h reaction. More interestingly, the catalyst has shown great solvent selectivity with respect to the product distribution. Finally, the catalyst can be easily separated magnetically for reuse and no obvious loss of activity was observed after five consecutive runs.
- Bo, Lili,Hu, Yusen,Zhang, Zhixia,Balanay, Mannix,Fan, Haiyan,Tong, Jinhui
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p. 182 - 188
(2018/08/17)
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- Copper based coordination polymers based on metalloligands: Utilization as heterogeneous oxidation catalysts
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This work presents the synthesis and characterization of two Cu(ii)-based coordination polymers prepared by utilizing two different Co(iii)-based metalloligands offering appended arylcarboxylic acid groups. Both coordination polymers are three-dimensional in nature and present pores and channels filled with water molecules. Both coordination polymers function as heterogeneous catalysts for the epoxidation of various olefins using O2 while employing isobutyraldehyde as the coreductor and for peroxide-mediated oxidation of assorted benzyl alcohols. The catalytic results illustrate efficient oxidation reactions, whereas the hot-fltration test and leaching experiments indicate the true heterogeneous nature of the catalysis.
- Kumar, Gulshan,Hussain, Firasat,Gupta, Rajeev
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p. 16985 - 16994
(2019/01/03)
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- Synthesis, Characterization, and Efficient Catalytic Activities of a Nickel(II) Porphyrin: Remarkable Solvent and Substrate Effects on Participation of Multiple Active Oxidants
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A new nickel(II) porphyrin complex, [NiII(porp)] (1), has been synthesized and characterized by 1H NMR, 13C NMR and mass spectrometry analysis. This NiII porphyrin complex 1 quantitatively catalyzed the epoxidation reaction of a wide range of olefins with meta-chloroperoxybenzoic acid (m-CPBA) under mild conditions. Reactivity and Hammett studies, H218O-exchange experiments, and the use of PPAA (peroxyphenylacetic acid) as a mechanistic probe suggested that participation of multiple active oxidants NiII?OOC(O)R 2, NiIV-Oxo 3, and NiIII-Oxo 4 within olefin epoxidation reactions by the nickel porphyrin complex is markedly affected by solvent polarity, concentration, and type of substrate. In aprotic solvent systems, such as toluene, CH2Cl2, and CH3CN, multiple oxidants, NiII?(O)R 2, NiIV-Oxo 3, and NiIII-Oxo 4, operate simultaneously as the key active intermediates responsible for epoxidation reactions of easy-to-oxidize substrate cyclohexene, whereas NiIV-Oxo 3 and NiIII-Oxo 4 species become the common reactive oxidant for the difficult-to-oxidize substrate 1-octene. In a protic solvent system, a mixture of CH3CN and H2O (95:5), the NiII?OOC(O)R 2 undergoes heterolytic or homolytic O?O bond cleavage to afford NiIV-Oxo 3 and NiIII-Oxo 4 species by general acid catalysis prior to direct interaction between 2 and olefin, regardless of the type of substrate. In this case, only NiIV-Oxo 3 and NiIII-Oxo 4 species were the common reactive oxidant responsible for olefin epoxidation reactions.
- Ahn, Hye Mi,Bae, Jeong Mi,Kim, Min Jeong,Bok, Kwon Hee,Jeong, Ha Young,Lee, Suk Joong,Kim, Cheal
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p. 11969 - 11976
(2017/09/07)
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- Dinuclear Iron(III) and Nickel(II) Complexes Containing N-(2-Pyridylmethyl)-N′-(2-hydroxyethyl)ethylenediamine: Catalytic Oxidation and Magnetic Properties
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Dinuclear FeIII and NiII complexes, [(phenO)Fe(N3)]2(NO3)2 (1) and [(phenOH)Ni(N3)2]2 (2), were prepared by treating Fe(NO3)3?9 H2O and Ni(NO3)2?6 H2O in methanol, respectively, with phenOH (=N-(2-pyridylmethyl)-N′-(2-hydroxyethyl)ethylenediamine) and NaN3; both 1 and 2 were characterized by elemental analysis, IR spectroscopy, X-ray diffraction, and magnetic susceptibility measurements. Two ethoxo-bridged FeIII and two azido-bridged NiII were observed in 1 and 2, respectively; corresponding antiferromagnetic interaction via the bridged ethoxo groups and strong ferromagnetic coupling via the bridged end-on azido ligands within the dimeric unit were observed. Complex 1 did not exhibit any catalytic activity, while 2 exhibited excellent catalytic activities for the epoxidation of aliphatic, aromatic, and terminal olefins.
- Jeong, Ah Rim,Shin, Jong Won,Jeong, Jong Hwa,Bok, Kwon Hee,Kim, Cheal,Jeong, Donghyun,Cho, Jaeheung,Hayami, Shinya,Min, Kil Sik
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p. 3023 - 3033
(2017/03/13)
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- Cubane cluster type catalyst, synthesizing method of the same and epoxidation of olefin using of the same
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The present invention relates to a cubane cluster type catalyst, a synthesizing method thereof, and an epoxidation method of olefin using the same, and more specifically, to a cobalt metal complex used as a catalyst of an oxidation reaction of hydrocarbon, a synthesizing method thereof, and an epoxidation method of olefin using the same. The epoxidation method of olefin according to one embodiment of the present invention comprises the steps of: (a) synthesizing (S10) a cobalt complex compound in a cubane cluster type; (b) using the cubane cluster type cobalt complex compound as a catalyst and for a solvent having 1:1 of a volume ratio of acetonitrile (CH_3CN) and methylene chloride (CH_2Cl_2), using olefin as a substrate and adding (S20) meta-Chloroperoxybenzoic (mCPBA) acid, an oxidant; and (c) performing an epoxidation reaction at a room temperature. The purpose of the present invention is to provide a cubane cluster type catalyst, a synthesizing method thereof, and an epoxidation method of olefin using the same which can replace a role of metal enzymes playing a catalyst role in oxidation reactions, and in oxidation reactions of various organic substrates, has an excellent catalytic activation without a high temperature and a high pressure and can be used in organic synthesis which is commercially used.COPYRIGHT KIPO 2017
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Paragraph 0037-0040
(2018/03/23)
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- Synthesis, Characterization, and Catalytic Activities of A Nickel(II) Monoamido-Tetradentate Complex: Evidence For NiIII–Oxo and NiIV–Oxo Species
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A new mononuclear nickel(II) complex, [NiII(dpaq)Cl] (1), containing a tetradentate monoamido ligand, dpaq (dpaq=2-[bis(pyridin-2-ylmethyl)amino]-N-(quinolin-8-yl)acetamide), has been synthesized and characterized by IR spectroscopy, elemental analysis, and UV/Vis spectroscopy. The structure of the nickel complex has been determined by X-ray crystallography. This nonheme NiII complex 1 catalyzed the epoxidation reaction of a wide range of olefins with meta-chloroperoxybenzoic acid (m-CPBA) under mild conditions. Olefin epoxidation using this catalytic system has been proposed to involve a new reactive NiIV–oxo (4) species, based on the evidence from a PPAA (peroxyphenylacetic acid) probe, Hammett studies, H218O exchange experiments, and ESI mass spectroscopic analysis. Moreover, the nature of solvent significantly influenced partitioning between heterolytic and homolytic O?O bond cleavage of the Ni–acylperoxo intermediate (2). The O?O bond of 2 proceeded predominantly through heterolytic cleavage in a protic solvent, such as CH3OH. These results suggest that possibly a NiIV–oxo species is a common reactive intermediate in protic solvents. The two active oxidants, namely NiIV–oxo (3) and NiIII–oxo (4), which are responsible for stereospecific olefin epoxidation and radical-type oxidations, respectively, operate in aprotic solvents.
- Bok, Kwon Hee,Lee, Myoung Mi,You, Ga Rim,Ahn, Hye Mi,Ryu, Ka Young,Kim, Sung-Jin,Kim, Youngmee,Kim, Cheal
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p. 3117 - 3125
(2017/03/14)
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- Activated vs. pyrolytic carbon as support matrix for chemical functionalization: Efficient heterogeneous non-heme Mn(II) catalysts for alkene oxidation with H2O2
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Two types of heterogeneous catalytic materials, MnII-L3imid@Cox and MnII-L3imid@PCox, have been synthesized and compared by covalent grafting of a catalytically active [MnII-L3imid] complex on the surface of an oxidized activated carbon (Cox) and an oxidized pyrolytic carbon from recycled-tire char (PCox). Both hybrids are non-porous bearing graphitic layers intermixed with disordered sp2/sp3 carbon units. Raman spectra show that (ID/IG)activatedcarbon > (ID/IG)pyrolyticcarbon revealing that oxidized activated carbon(Cox) is less graphitized than oxidized pyrolytic carbon (PCox). The MnII-L3imid@Cox and MnII-L3imid@PCox catalysts were evaluated for alkene oxidation with H2O2 in the presence of CH3COONH4. Both showed high selectivity towards epoxides and comparing the achieved yields and TONs, they appear equivalent. However, MnII-L3imid@PCox catalyst is kinetically faster than the MnII-L3imid@Cox (accomplishing the catalytic runs in 1.5 h vs. 5 h). Thus, despite the similarity in TONs MnII-L3imid@PCox achieved extremely higher TOFs vs. MnII-L3imid@Cox. Intriguingly, in terms of recyclability, MnII-L3imid@Cox could be reused for a 2th run showing a ～20% loss of its catalytic activity, while MnII-L3imid@PCox practically no recyclable. This phenomenon is discussed in a mechanistic context; interlinking oxidative destruction of the Mn-complex with high TOFs for MnII-L3imid@PCox, while the low-TOFs of MnII-L3imid@Cox are preventive for the oxidative destruction of the Mn-complex.
- Simaioforidou,Papastergiou,Margellou,Petrakis,Louloudi
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p. 516 - 525
(2016/12/16)
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- A 1,2-pentanediol preparation method
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The invention discloses a preparation method of 1,2-cyclopentanediol. The preparation method comprises the following steps: 1) oxidizing reaction, namely adding a certain amount of raw materials, namely cyclopentene, a catalyst, a cocatalyst and hydrogen peroxide to a reaction system, reacting at 35-45 DEG C for 4-6 hours, so as to obtain an oxidative product cyclopentene oxide of cyclopentene; 2) hydrolysis reaction, adding a certain amount of deionized water to the oxidative product cyclopentene oxide, carrying out hydrolysis reaction at 70-90 DEG C for 80-110 hours based on a solid proton acid as the catalyst; and 3) product separation, namely distilling the mixture obtained after hydrolysis reaction at reduced pressure to obtain the product 1,2-cyclopentanediol. According to the preparation method of the 1,2-cyclopentanediol, hydrogen peroxide is adopted as an oxidant; Fu-Cu main catalyst and KCl cocatalyst are adopted to catalyze; the oxidant is easily available and low in cost; the water generated by reaction does not pollute the environment; the catalyst is easily available, low in cost, small in toxicity, high in activity, and strong in stability; the product is high in yield; and the production process is simple and easy to operate.
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Paragraph 0020-0022
(2017/02/09)
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- A heteropoly acid hyamines catalytic olefin epoxidation method
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The invention provides a method utilizing quaternary ammonium heteropolyate to catalyze alkene epoxidation. Alkene and an oxidant carry out reactions in the presence of a quaternary ammonium heteropolyate catalyst, a reductive auxiliary agent, and an organic solvent for 2 to 10 hours at a temperature of 50 to 80 DEG C. After the reaction, the precipitated catalyst can be separated and recycled, and the reaction liquid is subjected to a steaming treatment so as to obtain the target epoxides. The method has the advantages of simple technology, mild conditions, green, and environment-friendliness, and has a vast industrial application prospect, and moreover, the catalyst is easy to separate, recycle and reutilize.
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Paragraph 0023; 0024; 0025
(2017/03/14)
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- Trinuclear nickel and cobalt complexes containing unsymmetrical tripodal tetradentate ligands: Syntheses, structural, magnetic, and catalytic properties
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The coordination chemistries of the tetradentate N2O2-type ligands N-(2-pyridylmethyl)iminodiethanol (H2pmide) and N-(2-pyridylmethyl)iminodiisopropanol (H2pmidip) have been investigated with nickel(ii) and cobalt(ii/iii) ions. Three novel complexes prepared and characterized are [(Hpmide)2Ni3(CH3COO)4] (1), [(Hpmide)2Co3(CH3COO)4] (2), and [(pmidip)2Co3(CH3COO)4] (3). In 1 and 2, two terminal nickel(ii)/cobalt(ii) units are coordinated to one Hpmide- and two CH3CO2-. The terminal units are each connected to a central nickel(ii)/cobalt(ii) cation through one oxygen atom of Hpmide- and two oxygen atoms of acetate ions, giving rise to nickel(ii) and cobalt(ii) trinuclear complexes, respectively. Trinuclear complexes 1 and 2 are isomorphous. In 3, two terminal cobalt(iii) units are coordinated to pmidip2- and two CH3CO2-. The terminal units are each linked to a central cobalt(ii) cation through two oxygen atoms of pmidip2- and one oxygen atom of a bidentate acetate ion, resulting in a linear trinuclear mixed-valence cobalt complex. 1 shows a weak ferromagnetic interaction with the ethoxo and acetato groups between the nickel(ii) ions (g = 2.24, J = 2.35 cm-1). However, 2 indicates a weak antiferromagnetic coupling with the ethoxo and acetato groups between the cobalt(ii) ions (g = 2.37, J = -0.5 cm-1). Additionally, 3 behaves as a paramagnetic cobalt(ii) monomer, due to the diamagnetic cobalt(iii) ions in the terminal units (g = 2.53, =D= = 36.0 cm-1). No catalytic activity was observed in 1. However, 2 and 3 showed significant catalytic activities toward various olefins with modest to good yields. 3 was slightly less efficient toward olefin epoxidation reaction than 2. Also 2 was used for terminal olefin oxidation reaction and was oxidised to the corresponding epoxides in moderate yields (34-75%) with conversions ranging from 47-100%. The cobalt complexes 2 and 3 promoted the O-O bond cleavage to ～75% heterolysis and ～25% homolysis.
- Shin, Jong Won,Jeong, Ah Rim,Lee, Sun Young,Kim, Cheal,Hayami, Shinya,Min, Kil Sik
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p. 14089 - 14100
(2016/11/06)
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- Preparation method for 1,2-epoxycyclopentane
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The invention provides a preparation method for 1,2-epoxycyclopentane. According to the method, 1,2-cyclopentene oxide is synthesized from cyclopentene through oxidation in the presence of an organic solvent and an auxiliary agent with a titanium silicalite molecular sieve as a catalyst and hydrogen peroxide as an oxidizing agent.
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Paragraph 0016-0021
(2017/03/17)
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- Comparison of enzymatic and acid hydrolysis of bound flavor compounds in model system and grapes
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Four synthesized terpenyl-β-D-glycopyranosides (geranyl, neryl, citronellyl, myrtenyl) were subjected to enzymatic (AR 2000, pH 5.5) and acid (citric buffer, pH 2.5) hydrolysis. Decrease of glycosides was measured by HPLC and the volatiles released - by comprehensive gas chromatography-mass spectrometry (GC x GC-ToF-MS). Enzymatic hydrolysis performed for 21 h yielded 100% degree of hydrolysis for all glycosides but citronellyl (97%). Degree of acid hydrolysis was highly dependent on type of aglycone and the conditions. The highest degree was achieved for geraniol, followed by citronellol and nerol. Myrtenylo-β-D-glycopyranoside was the most resistant glycoside to hydrolysis. Acid hydrolysis degree was also related to temperature/time combination, the highest being for 100 °C and 2 h. In a result of enzymatic hydrolysis 85-91% of total peak areas was terpene aglycone, whereas for acid hydrolysis the area of released terpene aglycone did not exceed 1.3% of total peak area indicating almost complete decomposition/transformation of terpenyl aglycone.
- Dziadas, Mariusz,Jeleń, Henryk H.
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p. 412 - 418
(2015/06/17)
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- Selective oxidation of styrene catalyzed by cerium-doped cobalt ferrite nanocrystals with greatly enhanced catalytic performance
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The rare earth metal Ce-doped cobalt ferrite samples CexCo1?xFe2O4 (x?=?0.1, 0.3, 0.5) were prepared by the sol–gel autocombustion route. The as-prepared samples were characterized by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, ICP–atomic emission spectroscopy, and N2 physisorption. Their catalytic performance was evaluated in oxidation of styrene using hydrogen peroxide (30%) as oxidant. Compared with pristine CoFe2O4, the Ce-doped samples were found to be more efficient catalysts for the oxidation of styrene to benzaldehyde, with greatly enhanced catalytic performance. Especially, when Ce0.3Co0.7Fe2O4 was used as catalyst, 90.3% styrene conversion and 91.5% selectivity for benzaldehyde were obtained at 90?°C for 9?h reaction. The catalyst can be magnetically separated easily for reuse, and no obvious loss of activity was observed when it was reused in five consecutive runs.
- Tong, Jinhui,Li, Wenyan,Bo, Lili,Wang, Huan,Hu, Yusen,Zhang, Zhixia,Mahboob, Abdulla
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p. 474 - 481
(2016/11/18)
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- Catalytic potentials of homodioxo-bimetallic dihydrazone complexes of uranium and molybdenum in a homogeneous oxidation of alkenes
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The catalytic potentials of dioxomolybdenum(VI) and dioxouranium(VI) homobimetallic bis-ONO tridentate (2-hydroxy-1-benzylidene)malonyl-, succinyl-, and terephthalo-dihydrazone complexes were studied in homogeneous oxidation processes of various aliphatic and cyclic alkenes using aqueous H2O2 or TBHP (tert-butyl hydroperoxide) as a terminal oxidant. The catalytic potentiality is quantitative and highly selective to afford the corresponding oxide product with MoVIO2 complexes which is 5 times more than that with UVIO2 complexes using aqueous H2O2 or TBHP. Effect of various solvents and temperatures was investigated in the oxidation of 1,2-cyclooctene catalyzed by MoVIO2 complexes using aqueous H2O2 results that the most favored solvent is acetonitrile at an optimal temperature is 70 °C. The mechanistic pathway was tentatively described and discussed
- Adam, Mohamed Shaker S.
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p. 1823 - 1836
(2015/10/29)
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- Bismuth-substituted "sandwich" type polyoxometalate catalyst for activation of peroxide: Umpolung of the peroxo intermediate and change of chemoselectivity
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The epoxidation of alkenes with peroxides by WVI, MoVI, VV, and TiIV compounds is well established, and it is well accepted that the active intermediate peroxo species are electrophilic toward nucleophilic substrates. Polyoxotungstates, for example, those of the "sandwich" structure, [WZn(TM-L)2(ZnW9O34)2]q- in which TM = transition metal and L = H2O, have in the past been found to be excellent epoxidation catalysts. It has now been found that substituting the Lewis basic BiIII into the terminal position of the "sandwich" polyoxometalate structure to yield [Zn2BiIII2(ZnW9O34)2]14- leads to an apparent umpolung of the peroxo species and formation of a nucleophilic peroxo intermediate. There are two lines of evidence that support the formation of a reactive nucleophilic peroxo intermediate: (1) More electrophilic sulfoxides are more reactive than more nucleophilic sulfides, and (2) nonfunctionalized aliphatic alkenes and dienes showed ene type reactivity rather than epoxidation pointing toward "dark" formation of singlet oxygen from the nucleophilic intermediate peroxo species. Allylic alcohols reacted much faster than alkenes but showed chemoselectivity toward C-H bond activation of the alcohol and formation of aldehydes or ketones rather than epoxidation. This explained via alkoxide formation at the BiIII center followed by oxidative β-elimination.
- Amanchi, Srinivasa Rao,Khenkin, Alexander M.,Diskin-Posner, Yael,Neumann, Ronny
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p. 3336 - 3341
(2015/06/16)
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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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- A new halide-free efficient reaction-controlled phase-transfer catalyst based on silicotungstate of [(C18H37)2(CH 3)2N]3[SiO4H(WO5) 3] for olefin epoxidation, oxidation of sulfides and alcohols with hydrogen peroxide
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A new reaction-controlled phase-transfer catalyst based on silicotungstate of [(C18H37)2(CH3) 2N]3[SiO4H(WO5)3] for oxidation of hydrocarbons is developed. The catalyst is a new heteropoly compound with silicon as heteroatom, which is different to the previously reported reaction-controlled phase transfer catalysts that were composed of quaternary ammonium heteropolyoxotungstates of [π-C5H 5N(CH2)15CH3]3[PW 4O16] and [π-C5H5N(CH 2)15CH3]3[PW4O 32] with phosphorus as heteroatom. The oxidation of various alkenes (such as linear terminal olefins, internal olefins, cyclic olefins and unactivated alkenes) to epoxides, sulfides to sulfoxides and sulfones, alcohols to carbonyl compounds, are successfully catalyzed by this recyclable and environmentally benign catalyst using H2O2 as oxidant and ethyl acetate as solvent. This catalyst is not only capable of catalyzing homogeneous oxidation of organic substrates with unique reaction-controlled phase-transfer character, but also avoids the use of toxic solvents. The catalyst could be easily recovered and reused after reaction, and the epoxidation of cyclohexene was performed twenty times without obvious loss in activity. The fresh catalyst and the used one were characterized by ICP, IR, UV-vis, 29Si MAS NMR and 183W NMR in detail. the Partner Organisations 2014.
- Ma, Baochun,Zhao, Wei,Zhang, Fuming,Zhang, Yingshuai,Wu, Songyun,Ding, Yong
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p. 32054 - 32062
(2014/08/18)
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- Synthesis, crystal structures, and catalytic oxidation properties of oxidovanadium(V) complexes with Schiff base ligands
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Two new Schiff base ligands 2-chloro-N′-(5-fluoro-2- hydroxybenzylidene)benzohydrazide (H2La) and 4-fluoro-2-{[2-(2-hydroxyethylamino)ethylimino]methyl}phenol (HLb) were synthesized and characterized. Their respective oxid
- Yang, Kui-Hua
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p. 469 - 475
(2014/05/20)
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- Synthesis, crystal structures, and catalytic oxidation properties of oxidovanadium(v) complexes with hydrazone and hydroxamate ligands
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Two new oxidovanadium(V) complexes with hydrazone ligands and hydroxamate ligands were synthesized and characterized by IR and 1H NMR spectroscopy, elemental analysis and single crystal X-ray diffraction. The coordination sphere of each V atom
- Yang, Kui-Hua
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p. 629 - 636
(2014/12/12)
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- Synthesis, characterization, magnetic and catalytic properties of a ladder-shaped MnII coordination polymer
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[Mn(LH)(H2O)]n {1, where LH2- is the dianion of N-(4-carboxybenzyl)iminodiacetic acid} has been synthesized and its crystal structure has been determined. The crystal of 1 is built from 1D polymeric ladder-shaped chains that extend to a 3D supramolecular architecture through H-bonds. The compound was characterized with spectroscopic and physicochemical techniques. Variable-temperature magnetic data suggest that there are weak antiferromagnetic interactions. Compound 1 has been evaluated as a heterogeneous oxidation catalyst. It catalyzes alkene epoxidation selectively in relatively high yields. Copyright
- Lymperopoulou, Smaragda,Papastergiou, Maria,Louloudi, Maria,Raptopoulou, Catherine P.,Psycharis, Vassilis,Milios, Constantinos J.,Plakatouras, John C.
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p. 3638 - 3644
(2014/08/18)
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- Synthesis, Characterization, Magnetic and Catalytic Properties of a Ladder-Shaped MnII Coordination Polymer
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[Mn(LH)(H2O)]n {1, where LH2- is the dianion of N-(4-carboxybenzyl)iminodiacetic acid} has been synthesized and its crystal structure has been determined. The crystal of 1 is built from 1D polymeric ladder-shaped chains that extend to a 3D supramolecular architecture through H-bonds. The compound was characterized with spectroscopic and physicochemical techniques. Variable-temperature magnetic data suggest that there are weak antiferromagnetic interactions. Compound 1 has been evaluated as a heterogeneous oxidation catalyst. It catalyzes alkene epoxidation selectively in relatively high yields.
- Lymperopoulou, Smaragda,Papastergiou, Maria,Louloudi, Maria,Raptopoulou, Catherine P.,Psycharis, Vassilis,Milios, Constantinos J.,Plakatouras, John C.
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p. 3638 - 3644
(2015/04/27)
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- Activation of carboxylic acids in asymmetric organocatalysis
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Organocatalysis, catalysis using small organic molecules, has recently evolved into a general approach for asymmetric synthesis, complementing both metal catalysis and biocatalysis.1 Its success relies to a large extent upon the introduction of novel and generic activation modes.2 Remarkably though, while carboxylic acids have been used as catalyst directing groups in supramolecular transition-metal catalysis,3 a general and well-defined activation mode for this useful and abundant substance class is still lacking. Herein we propose the heterodimeric association of carboxylic acids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self-assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylic acid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine-opening reaction with carboxylic acids as nucleophiles. Activation by dimerization: There is still no general activation mode for carboxylic acids in organocatalysis. The formation of heterodimers between chiral phosphoric acid diesters and carboxylic acids can be used to activate and direct reactivity of the latter in asymmetric reactions. This novel principle has been applied to the ring-opening desymmetrization and kinetic resolution of aziridines leading to valuable amino alcohols.
- Monaco, Mattia Riccardo,Poladura, Belen,Diaz De Los Bernardos, Miriam,Leutzsch, Markus,Goddard, Richard,List, Benjamin
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supporting information
p. 7063 - 7067
(2014/07/08)
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- Initiator-free hydrocarbon oxidation using supported gold nanoparticles
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The oxidation of cyclic alkenes (cyclopentene, cyclohexene, cycloheptene and cyclooctene) has been carried out under green solvent-free conditions using ambient air as the oxidant gas with a carbon-supported gold catalyst. We show that radical initiators are only required for this reaction when the cyclic alkene contains a stabilizer molecule, such as 6-bis(t-butyl)-4-methylphenol (BHT) or 3-octadecyl-(3,5-di-t-butyl-4-hydroxyphenyl)-propanoate (irganox 1076). We show that either removing the stabilizer chemically or sourcing the cycloalkane without the stabilizer the oxidation, both with and without radical initiator, is identical. This indicates that the only function of the radical initiator is to counteract the stabilizer. We have extended this work to show that stabilizer-free internal linear alkenes can be effectively epoxidised with air using the carbon-supported gold catalyst. However, unfortunately linear α-alkenes still require the addition of an initiator to achieve reaction. This work demonstrates that removal of a sacrificial reagent from a reaction is possible which adheres to the principles of green chemistry. This journal is the Partner Organisations 2014.
- Alshammari, Hamed,Miedziak, Peter J.,Davies, Thomas E.,Willock, David J.,Knight, David W.,Hutchings, Graham J.
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p. 908 - 911
(2014/04/03)
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- Length tunable porphyrinoid porous coordination polymer rods and their heterogeneous catalytic study on olefin oxidation
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We developed a series of micro-size hexagon-faced plate and rods from Mn(III)-porphyrin and In(III) whose lengths were modulated by water. Regardless of a wide range of length distribution, they are isostructural. In addition, the heterogeneous olefin oxidation was performed.
- Kim, Sundol,Lee, Young Sun,Lee, Da Hee,Hyun, Min Young,Hong, Jin-Yeon,Huh, Seong,Kim, Cheal,Lee, Suk Joong
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- Mesoporous carbon nitride synthesized by nanocasting with urea/formaldehyde and metal-free catalytic oxidation of cyclic olefins
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Mesostructured carbon nitride has been synthesized by nanocasting method with urea/formaldehyde as carbon and nitrogen sources by using disk-shaped 2D hexagonal mesoporous silica (INC-2) as a hard template. The resulted mesoporous carbon nitride (UF-MCN) was characterized as a graphitic structure with hexagonal pores of 3-4 nm and short channels in the submicron range. The catalytic oxidation ability of UF-MCN was demonstrated in the metal-free oxidation of cyclic olefins with hydrogen peroxide. The conversions for cyclopentene, cyclohexene and cis-cyclooctene were obtained in the range of 65-80% and selectivities onto epoxides were 40-90%, respectively. The UF-MCN could illustrate the considerable catalytic oxidation activities due to the existence of surface oxygen species.
- Min, Byung-Hoon,Ansari, Mohd Bismillah,Mo, Yong-Hwan,Park, Sang-Eon
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p. 156 - 163
(2013/08/24)
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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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- 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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- Synthesis of novel magnetic chitosan supported protonated peroxotungstate and its catalytic performance for oxidation
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A novel magnetically recoverable catalyst in which protonated peroxotungstate was immobilized into a network of cross-linked chitosan with a superparamagnetic Fe3O4 core (Fe3O 4-CS/HWO) was prepared, characterized and used in oxidation reactions. With H2O2 as oxidant, a wide range of substrates including olefins, sulfides, amines and allylic alcohols could be oxidized selectively, exhibiting a relatively high utilization percentage of H2O2. Due to the existence of peroxotungstate as well as the magnetic core, both improved catalytic performance and facilitated separation were achieved for the reaction process. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.
- Zhu, Jie,Wang, Peng Cheng,Lu, Ming
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p. 2587 - 2592
(2013/02/22)
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- Crosslinked isoxazole functionalized resin transition metal complexes - Use as polymeric catalysts for epoxidation of olefins
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Transition metal complexes on polymers were found to be highly efficient in many catalysis reactions. The activity of Fe(III), Co(II), Ni(II) and Cu(II) complexes of polystyrene bound Isoxazole resin have been tested towards the epoxidation of alkenes by
- Rajesh, K.,Rathika Nath, G.
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p. 1031 - 1036,6
(2020/08/24)
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- Enantiomerically enriched trans-diols from alkenes in one pot: A multicatalyst approach
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Multicatalysts consisting of non-natural oligopeptides with distinctly different catalytic moieties create molecular complexity in a multistep one-pot sequence starting from simple alkenes yielding highly enantiomerically enriched trans-diols. The Royal Society of Chemistry 2012.
- Hrdina, Radim,Mueller, Christian E.,Wende, Raffael C.,Wanka, Lukas,Schreiner, Peter R.
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supporting information; experimental part
p. 2498 - 2500
(2012/04/10)
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- Amide-based nonheme cobalt(III) olefin epoxidation catalyst: Partition of multiple active oxidants CoV=O, CoIV=O, and Co III-OO(O)CR
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A mononuclear nonheme cobalt(III) complex of a tetradentate ligand containing two deprotonated amide moieties, [Co(bpc)Cl2][Et 4N] (1; H2bpc=4,5-dichloro-1,2-bis(2-pyridine-2- carboxamido)benzene), was prepared and then characterized by elemental analysis, IR, UV/Vis, and EPR spectroscopy, and X-ray crystallography. This nonheme CoIII complex catalyzes olefin epoxidation upon treatment with meta-chloroperbenzoic acid. It is proposed that complex 1 shows partitioning between the heterolytic and homolytic cleavage of an O-O bond to afford Co V=O (3) and CoIV=O (4) intermediates, proposed to be responsible for the stereospecific olefin epoxidation and radical-type oxidations, respectively. Moreover, under extreme conditions, in which the concentration of an active substrate is very high, the Co-OOC(O)R (2) species is a possible reactive species for epoxidation. Furthermore, partitioning between heterolysis and homolysis of the O-O bond of the intermediate 2 might be very sensitive to the nature of the solvent, and the O-O bond of the Co-OOC(O)R species might proceed predominantly by heterolytic cleavage, even in the presence of small amounts of protic solvent, to produce a discrete Co V=O intermediate as the dominant reactive species. Evidence for these multiple active oxidants was derived from product analysis, the use of peroxyphenylacetic acid as the peracid, and EPR measurements. The results suggest that a less accessible CoV=O moiety can form in a system in which the supporting chelate ligand comprises a mixture of neutral and anionic nitrogen donors. Copyright
- Song, Young Joo,Hyun, Min Young,Lee, Jun Ho,Lee, Hong Gyu,Kim, Jin Hoon,Jang, Seung Pyo,Noh, Jin Young,Kim, Youngmee,Kim, Sung-Jin,Lee, Suk Joong,Kim, Cheal
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experimental part
p. 6094 - 6101
(2012/07/13)
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- Aerobic oxidation of cycloalkenes catalyzed by iron metal organic framework containing N-hydroxyphthalimide
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Iron metal organic framework [Fe(BTC)] loaded with N-hydroxyphthalimide (NHPI) promotes the aerobic oxidation of (cyclo)alkenes to give variable percentages of allylic oxidation products and the corresponding epoxide, dependidng on the nature of the substrate. In the case of cyclopentene and cyclohexene, aerobic oxidation catalyzed by NHPI/Fe(BTC) renders their corresponding unsaturated cyclic alcohol and ketone with 97% selectivity in 5 h at 6% and 12% conversion, respectively. Under the same experimental conditions, cyclooctene exhibited 95% selectivity toward the formation of cyclooctene oxide with 2% of cyclooctenol/one at 4 h. Cycloheptene as susbstrate exhibits an intermediate behavior, and the aerobic oxidation catalyzed by NHPI/Fe(BTC) leads to the formation of cycloheptenol/cycloheptenone with 77% selectivity, accompanied by 23% of cycloheptene oxide at 4 h. Further experiments with non-symmetric olefins exhibited also a mixture of products including epoxides and allyic products. A mechanism to explain these experimental results has been proposed.
- Dhakshinamoorthy, Amarajothi,Alvaro, Mercedes,Garcia, Hermenegildo
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experimental part
p. 259 - 265
(2012/06/01)
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- Monomeric, trimeric, and tetrameric transition metal complexes (Mn, Fe, Co) containing N,N-bis(2-pyridylmethyl)-2-aminoethanol/-ate: preparation, crystal structure, molecular magnetism and oxidation catalysis
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The reaction of N,N-bis(2-pyridylmethyl)-2-aminoethanol (bpaeOH), NaSCN/NaN3, and metal (M) ions [M = Mn(ii), Fe(ii/iii), Co(ii)] in MeOH, leads to the isolation of a series of monomeric, trimeric, and tetrameric metal complexes, namely [Mn(bpaeOH)(NCS)2] (1), [Mn(bpaeO)(N 3)2] (2), [Fe(bpaeOH)(NCS)2] (3), [Fe 4(bpaeO)2(CH3O)2(N3) 8] (4), [Co(bpaeOH)(NCS)2] (5), and [Co 3(bpaeO)2(NO3)(N3) 4](NO3) (6). These compounds have been investigated by single crystal X-ray diffractometry and magnetochemistry. In complex 1 the Mn(ii) is bonded to one bpaeOH and two thiocyanate ions, while in complex 2 it is coordinated to a deprotonated bpaeO- and two azide ions. The oxidation states of manganese ions are 2+ for 1 and 3+ for 2, respectively, indicating that the different oxidation states depend on the type of binding anions. The structures of monomeric iron(ii) and cobalt(ii) complexes 3 and 5 with two thiocyanate ions are isomorphous to that of 1. Compounds 1, 2, 3, and 5 exhibit high-spin states in the temperature range 5 to 300 K. 4 contains two different iron(iii) ions in an asymmetric unit, one is coordinated to a deprotonated bpaeO-, an azide ion, and a methoxy group, and the other is bonded to three azide ions and two oxygens from bpaeO- and a methoxy group. Two independent iron(iii) ions in 4 form a tetranuclear complex by symmetry. 4 displays both ferromagnetic and antiferromagnetic couplings (J = 9.8 and -14.3 cm-1) between the iron(iii) ions. 6 is a mixed-valence trinuclear cobalt complex, which is formulated as CoIII(S = 0)-CoII(S = 3/2)-CoIII(S = 0). The effective magnetic moment at room temperature corresponds to the high-spin cobalt(ii) ion (～4.27 μB). Interestingly, 6 showed efficient catalytic activities toward various olefins and alcohols with modest to excellent yields, and it has been proposed that a high-valent CoV-oxo species might be responsible for oxygen atom transfer in the olefin epoxidation and alcohol oxidation reactions. The Royal Society of Chemistry 2011.
- Shin, Jong Won,Rowthu, Sankara Rao,Hyun, Min Young,Song, Young Joo,Kim, Cheal,Kim, Bong Gon,Min, Kil Sik
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experimental part
p. 5762 - 5773
(2011/07/29)
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