1436-34-6Relevant articles and documents
Photochemical Epoxidation of Olefins with Molecular Oxygen Activated by Niobium Porphyrin: A Functional Model of Cytochrome P-450
Matsuda, Yoshihisa,sakamato, Shuji,Koshima, Hiroaki,Murakami, Yukito
, p. 6415 - 6416 (1985)
-
Alkoxysilylation of Ti-MWW lamellar precursors into interlayer pore-expanded titanosilicates
Wang, Lingling,Wang, Yong,Liu, Yueming,Wu, Haihong,Li, Xiaohong,He, Mingyuan,Wu, Peng
, p. 8594 - 8602 (2009)
Silylation of Ti-MWW lamellar precursor and subsequent calcination constructed an interlayer expanded structure, leading to novel titanosilicates with large pores. The silylating agents suitable for pore expansion were diethoxydimethylsilane, trimethylethoxysilane and triethoxymethylsilane containing methyl groups, which inhibited the intermolecular condensation of silanes effectively. In contrast to well-known 3D Ti-MWW with only medium pores of 10-membered rings, the silylation led to new crystalline structures with more open pores by ca. 2.5 A, as evidenced by the shift of layer-related diffractions to the lower-angle region in XRD patterns and the enlarged interlayer pores in HRTEM images. The interlayer expanded Ti-MWW was prepared readily from the corresponding hydrothermally synthesized precursors with a wide range of Ti contents (Si/Ti = 20-100). In addition, the pore expansion by silylation was realized under mild acid conditions with 0.1 M HNO3. The interlayer expanded Ti-MWW exhibited 3-7 times higher turnover number than 3D Ti-MWW in the oxidation of cyclohexene with H2O2. The Royal Society of Chemistry 2009.
Fast catalytic epoxidation with H2O2 and [γ-SiW10O36(PhPO)2]4- in ionic liquids under microwave irradiation
Berardi, Serena,Bonchio, Marcella,Carraro, Mauro,Conte, Valeria,Sartorel, Andrea,Scorrano, Gianfranco
, p. 8954 - 8957 (2007)
(Figure Presented) Olefin epoxidation by [γ-SiW10O 36(PhPO)2]4- and H2O2 occurs in hydrophobic ionic liquids (ILs), with yields and selectivity up to >99%. The catalytic IL phase is recyclable. Under MW irradiation the reaction occurs with up to 200 turnovers per minute. Simultaneous cooling is instrumental for quantitative H2O2 conversion.
Enhancement of alkene epoxidation activity of titanosilicates by gas-phase ammonia modification
Zhang, Liyan,Xu, Le,Sun, Jingjing,Jiang, Jingang,Liu, Yueming,Wu, Haihong,Wu, Peng
, p. 2205 - 2211,7 (2012)
Novel ammonia-treated titanosilicates have been prepared by heating the samples of Ti-MWW, TS-1 and Ti-Beta under pure ammonia gas flow at 673 K for a period of time. The ammonia modification improved their catalytic performance in liquid-phase oxidations. Especially, the catalytic activities of ammonified Ti-MWW, N-Ti-MWW, were enhanced greatly in the epoxidation of 1-hexene with H2O2. The reason that the ammonia treatment played such an important role in post-modification of titanosilicate was investigated in details. In comparison to the parent Ti-MWW catalyst, N-Ti-MMW was more robust and produced less coke in oxidation reactions.
A recyclable hybrid manganese(III) porphyrin magnetic catalyst for selective olefin epoxidation using molecular oxygen
Dias, Lucas D.,Carrilho, Rui M.B.,Henriques, César A.,Piccirillo, Giusi,Fernandes, Auguste,Rossi, Liane M.,Filipa Ribeiro,Calvete, Mário J.F.,Pereira, Mariette M.
, p. 331 - 341 (2018)
The synthesis and characterization of a hybrid Mn(III)-porphyrin magnetic nanocomposite is described. Moreover, a sustainable methodology for epoxidation of olefins is reported, using O2 as a green oxidant and the magnetic nanoparticle as a rec
Highly effective peroxidic epoxidation of olefins using hexathiocyanatorhenate(IV) as catalyst and bicarbonate as co-catalyst
Dinda, Subhajit,Roy Chowdhury, Sujoy,Abdul Malik,Bhattacharyya, Ramgopal
, p. 339 - 341 (2005)
In the presence of bicarbonate as co-catalyst hexathiocyanatorhenate(IV) functions as an extremely effective catalyst in the epoxidation of olefins using aqueous hydrogen peroxide as the terminal oxidant.
Methyltrioxorhenium/pyrazole - A highly efficient catalyst for the epoxidation of olefins
Herrmann, Wolfgang A.,Kratzer, Roland M.,Ding, Hao,Thiel, Werner R.,Glas, Holger
, p. 293 - 295 (1998)
A biphasic system consisting of 35% H2O2 and methyltrioxorhenium(VII)/pyrazole in CH2Cl2 catalyzes the epoxidation of a wide range of olefins in excellent yields. Both the reactivity and selectivity of the new c
Hydrogen peroxide activation by fluorophilic polyoxotungstates for fast and selective oxygen transfer catalysis
Carraro, Mauro,Gardan, Martino,Sartorel, Andrea,Maccato, Chiara,Bonchio, Marcella
, p. 14544 - 14548 (2016)
Fluorophilic polyoxotungstates perform the selective epoxidations of internal and terminal double bonds by hydrogen peroxide (H2O2) activation in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), under mild temperature conditions. A hybrid synergy of supramolecular interactions, involving the inorganic cluster and the fluorinated solvent, is envisaged to boost H2O2 activation and the oxygen transfer mechanism. 1,2-Epoxides have been obtained with >99% selectivity and 98% yield at T = 40-70 °C.
Scope and limitations of one-pot multistep reactions with heterogeneous catalysts: The case of alkene epoxidation coupled to epoxide ring-opening
Fraile, José M.,García, Nuria,Herrerías, Clara I.,Mayoral, José A.
, p. 15 - 20 (2011)
The combination of two reactions in one-pot multistep system requires the compatibility not only between the catalysts of both reactions, but also between all the reaction components and conditions. In the case of the coupling of alkene epoxidation and epoxide ring opening, it has been possible to synthesize cyanohydrin and azidohydrin derivatives through a simple process that involves a one-pot multistep process by using a mixture of two heterogeneous catalysts, a silica-grafted Ti catalyst and ytterbium chloride, whose efficiency depends on the reactivity of the starting alkene. In addition, in some cases the mixture of catalysts can be recovered and reused in several one-pot multistep cycles. However, this system is not possible with electron-deficient alkenes, as the basic catalyst required for epoxidation has shown to be incompatible with the ring-opening process.
Oxidation of Olefins with Hydrogen Peroxide and tert-Butyl Hydroperoxide on Ti-Beta Catalyst
Corma, A.,Esteve, P.,Martinez, A.,Valencia, S.
, p. 18 - 24 (1995)
The oxidation of a number of linear, branched, and cyclic olefins catalyzed by the large-pore Ti-Beta catalyst in the presence of H2O2 and TBHP as oxidants has been carried out under mild conditions.The influence of the olefin structure on its reactivity towards oxidation has been studied.Depending on the particular olefin structure, the reaction rate was seen to be mostly influenced by the intrinsic reactivity of the double bond, diffusional limitations, or steric factors.The latter were seen to be more pronounced in the oxidations with TBHP, owing to the bulkier Ti-OO-C(CH3)3 species which would be formed inside the zeolite pores.Oxidations with TBHP also proceeded at a lower rate than with H2O2.Close to 100percent selectivities to epoxides were found when TBHP was used as oxygen donor.In the case of H2O2 solvolysis of the oxirane ring in methanol solutions was the major secondary reaction observed.The rate of this reaction was seen to depend on the structure of the epoxide formed in the first step.In both cases, very little peroxide decomposition was observed under the reaction conditions used.
Selective oxidation of olefins with aqueous hydrogen peroxide over phosphomolybdic acid functionalized knitting aryl network polymer
Song, Xiaojing,Zhu, Wanchun,Yan, Yan,Gao, Hongcheng,Gao, Wenxiu,Zhang, Wenxiang,Jia, Mingjun
, p. 32 - 39 (2016)
A phosphomolybdic acid (PMA)-based heterogeneous catalyst, denoted as PMA/KAP, was prepared by immobilizing PMA onto a knitting aryl network polymer (KAP) based on triphenylphosphine (PPh3). The catalytic property of PMA/KAP was investigated for the selective oxidation of olefins with aqueous hydrogen peroxide (H2O2) as oxidant. When using ethyl acetate (EAC) as reaction medium, PMA/KAP performs higher activity and selectivity to epoxide for a variety of olefins, and it can be reused for several times without obvious loss of activity. When the reaction was carried out in acetonitrile (AN) medium, deactivation of PMA/KAP catalyst can be observed immediately. A variety of characterization results suggest that the degradation of PMA unit to (PO4[MoO(O2)2]4)3- occurs easily when the PMA/KAP catalyst is operated in H2O2/AN system, while such degradation behavior could be significantly inhibited when the catalyst is used in the system of H2O2/EAC. We proposed that the neighbouring P-containing ligands dispersed in the framework of KAP can produce a steric pocket with low electron density, which can promote the formation of multi-weak coordination interaction between PMA unit and several P ligands. Such multi-weak interaction can inhibit the degradation of PMA to (PO4[MoO(O2)2]4)3-, thus avoiding the leaching of active species from the KAP support, and resulting in the formation of relatively stable heterogeneous PMA supported catalyst for olefin epoxidation with H2O2 in the media of EAC.
Synthesis, Crystal Structures, and Catalytic Properties of Dioxomolybdenum(VI) Complexes Derived from 4-Chloro-2-{[4-Diethylamino-2-Hydroxybenzylidene]amino}phenol
Zhu
, p. 532 - 538 (2019)
Abstract: Two new dioxomolybdenum(VI) complexes, [MoO2L(EtOH)] (I) and [MoO2L(Sal)] (II), where L is the dianionic form of 4-chloro-2-{[4-(diethylamino)-2-hydroxybenzylidene]amino}phenol (H2L), Sal is 4-diethylaminosalicyl
Catalytic performance of [Ti,Al]-beta in the alkene epoxidation controlled by the postsynthetic ion exchange
Goa, Yasuhide,Wu, Peng,Tatsumi, Takashi
, p. 8401 - 8411 (2004)
The catalytic performance of [Ti,Al]-Beta in the alkene epoxidation controlled by the postsynthetic ion exchange was studied. When as-synthesized [Ti,Al]-Beta was treated with aqueous ammonium nitrate solution and successively calcined at low temperature, a dramatic enhancement of epoxide selectivity was attained in the liquid-phase epoxidation of cyclohexene using H2O2 as an oxidant in protic solvent methanol. Addition of H2O2 to the system of three non-titanosilicates (H-ZSM-5, silicalite-1, and deboronated B-Beta) produced no enhancement effect in the solvolysis of cyclohexene oxide. The optimum thermal treatment temperature to achieve the maximum epoxide yield was 473 K, where the postsynthetic [Ti,Al]-Beta exhibited a catalytic activity comparable to the sample directly calcined at 793 K; nevertheless, the epoxide selectivity was ≤ 63% for the former in contrast to 0% for the latter. [Ti,Al]-Beta ion-exchanged with quaternary ammonium acetate followed by mild calcination showed similarly high epoxide selectivity. Tetramethylammonium acetate was the best modifier, resulting in almost no loss of epoxidation activity. Regeneration of the ion-exchange treatments catalysts was achieved by the repeated calcination and ion-exchange treatments, making the catalyst reusable. The pH in the ion-exchange treatment strongly influenced the catalytic performance. The optimal pH of the treatments was ～ 10. High pH treatments caused the partial dissolution of [Ti,Al]-Beta frameworks to increase the activity but decreased the epoxide selectivity.
Alkylaminophosphazenes as Efficient and Tuneable Phase-Transfer Agents for Polyoxometalate-Catalysed Biphasic Oxidation with Hydrogen Peroxide
Craven, Michael,Yahya, Rana,Kozhevnikova, Elena F.,Robertson, Craig M.,Steiner, Alexander,Kozhevnikov, Ivan V.
, p. 200 - 208 (2016)
Alkylaminophosphazenes (RPN) are efficient and tuneable phase-transfer agents for environmentally benign biphasic oxidation with hydrogen peroxide catalysed by polyoxometalates (POMs). Substituent groups on the phosphazene ring can be varied to modify the
Anchoring of copper(II) complexes onto the organically modified MCM-41: Preparation, characterization and catalytic epoxidation
Jana, Sreyashi,Bhunia, Susmita,Dutta, Buddhadeb,Koner, Subratanath
, p. 225 - 232 (2011)
[Cu(diamine)(NO3)2] complexes have been anchored by substituting easily replaceable nitrate ligand with the amine groups of the organic-modified MCM-41. The amine group containing organic moiety (3-aminopropyl)triethoxysilane has been first anchored on the surface of MCM-41 via silicon alkoxide route. Then the [Cu(diamine)(NO3)2] [where diamine = N,N′-dimethyl-1,2-ethanediamine (NN′dmen) N,N-dimethyl-1,2-ethanediamine (NNdmen), and N,N-diethyl-1,2-ethanediamine (NNdeten)] complex was allowed to react with the modified MCM-41 for tethering the complexes onto mesoporous silica matrix. Copper complexes containing different substituted diamine ligands viz. N,N′-dimethyl-1,2- ethanediamine, N,N-dimethyl-1,2-ethanediamine, and N,N-diethyl-1,2-ethanediamine have also been prepared to compare the catalytic efficiency. The prepared catalysts have been characterized by infrared (FT-IR) and UV-vis spectroscopic, electron paramagnetic resonance (EPR), small-angle X-ray diffraction and N 2 sorption study. The catalytic efficacy in the epoxidation reaction depends on the bulkiness of the substituted group in diamine. Notably, styrene shows an impressive conversion (94%) with tert-butylhydroperoxide (tert-BuOOH) over the Cu(NNdmen)-MCM-41 catalyst. Whereas, conversion in styrene to styrene-oxide reaction were only 78% and 48% with Cu(NNdeten)-MCM-41 and Cu(NN′dmen)-MCM-41 catalysts, respectively.
Catalysis of the epoxidation of olefins
Laszlo,Levart,Singh
, p. 3167 - 3168 (1991)
By analogy between the oxo forms of vanadium (V) and iron (IV), the latter being the active species in oxidations by cytochrome P-450, the system constituted by vanadium oxide (catalyst) and 6-butylhydroperoxide (oxidant) gives good results in the conversion of olefins to the corresponding epoxides.
In situ fabricated MOF-cellulose composite as an advanced ROS deactivator-convertor: Fluoroswitchable bi-phasic tweezers for free chlorine detoxification and size-exclusive catalytic insertion of aqueous H2O2
Bankar, Balasaheb D.,Biradar, Ankush V.,Goswami, Ranadip,Neogi, Subhadip,Pillai, Renjith S.,Rajput, Sonal,Seal, Nilanjan
, p. 4316 - 4332 (2022/03/07)
Combining the merits of structural diversity, and purposeful implantation of task-specific functionalities, metal-organic frameworks (MOFs) instigate targeted reactive oxygen species (ROS) scavenging and concurrent detoxification via self-calibrated emission modulation. Then again, grafting of catalytically active sites in MOFs can benefit developing a greener protocol to convert ROS generators to technologically important building blocks, wherein tailorable MOF-composite fabrication is highly sought for practical applications, yet unexplored. The chemo-robust and hydrogen-bonded framework encompassing free -NH2 moiety affixed pores serves as an ultra-fast and highly regenerable fluoro-probe for selective detection of toxic ROS producers hypochlorite ion (ClO-) and H2O2 with record-level nanomolar sensitivity. While the bio-relevant antioxidant l-ascorbic acid (AA) imparts notable quenching to the MOF, a significant 3.5 fold emission enhancement with bi-phasic colorimetric variation ensues when it selectively scavenges ClO- from uni-directional porous channels through an unprecedented molecular tweezer approach. Apart from a battery of experimental evidence, density functional theory (DFT) results validate "on-off-on"fluoroswitching from redistribution of MOF orbital energy levels, and show guest-mediated exclusive transition from "Tight state"to "Loose state". The coordination frustrated metal site engineered pore-wall benefits the dual-functionalized MOF in converting the potential ROS generator H2O2via selective alkene epoxidation under mild-conditions. Importantly, sterically encumbered substrates exhibit poor conversion and demonstrate first-ever pore-fitting-induced size selectivity for this benign oxidation. Judiciously planned control experiments in combination with DFT-optimized intermediates provide proof-of-concept to the ionic route of ROS conversion. Considering an effective way to broaden the advanced applications of this crystalline material, reconfigurable MOF@cotton fiber (CF) is fabricated via in situ growth, which scavenges free chlorine and concomitantly squeezes it upon exposure to AA with obvious colorimetric changes over multiple real-life platforms. Furthermore, multi-cyclic alkene epoxidation by MOF@CF paves the way to futuristic continuous flow reactors that truly serves this smart composite as a bimodal ROS deactivator-convertor and explicitly denotes it as an advanced promising analogue from contemporary state-of-the-art materials.
Synthesis, characterization and catalytic activities of nonheme manganese(III) complexes: Preferential formation of cis olefin oxide owing to steric hindrance
Kim, Cheal,Lee, Jiyoung,Moon, Sungjin,Park, Soyoung
, (2022/03/15)
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.
Proton Switch in the Secondary Coordination Sphere to Control Catalytic Events at the Metal Center: Biomimetic Oxo Transfer Chemistry of Nickel Amidate Complex
Kim, Soohyung,Jeong, Ha Young,Kim, Seonghan,Kim, Hongsik,Lee, Sojeong,Cho, Jaeheung,Kim, Cheal,Lee, Dongwhan
supporting information, p. 4700 - 4708 (2021/02/12)
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.
