- Synthesis, Characterization, and Crystal Structures of Dioxomolybdenum(VI) Complexes Derived from Similar Tridentate Hydrazone Compounds with Catalytic Property
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Abstract: Two hydrazone compounds 2-chloro-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide (H2L1) and N'-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone compounds, two new structurally similar dioxomolybdenum(VI) complexes, [MoO2L1(CH3OH)] (I) and [MoO2L2(CH3OH)] (II), were prepared and characterized by IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files nos. 1566491 (I) and 1566492 (II)). Complex I crystallizes as the triclinic space group (Formula presented.) with unit cell dimensions a = 8.0750(5), b = 10.5223(7), c = 10.8110(7) ?, α = 96.975(2)°, β = 97.909(2)°, γ = 104.497(2)°, V = 869.2(1) ?3, Z = 2, R1 = 0.0323, wR2 = 0.0620, GOOF = 1.089. Complex II crystallizes as the monoclinic space group P21/n with unit cell dimensions a = 11.680(1), b = 10.496(2), c = 14.879(2) ?, β = 98.862(2)°, V?= 1802.2(4) ?3, Z = 4, R1 = 0.0270, wR2 = 0.0675, GOOF = 1.111. X-ray analysis indicates that the complexes are mononuclear dioxomolybdenum(VI) species with the Mo atoms in octahedral coordination. The complexes were studied for their catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Yang,Diao,Ye,Zou
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- Synthesis and Crystal Structures of Oxidovanadium(V) Complexes Derived from Hydrazones with the Catalytic Property
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Two new structurally similar oxidovanadium(V) complexes [VOL1L] (1) and [VOL2L] (2) (L = acetohydroxamate) derived from N′-(5-bromo-2-hydroxybenzylidene)-2-methylbenzohydrazide (H2L1) and N′-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) hydrazones are prepared and characterized by elemental analyses, FT-IR, 1H NMR, and single crystal X-ray diffraction (CIF files CCDC Nos. 1859442 (1) and 1859446 (2)). The V atoms in the complexes are in the octahedral coordination, with hydrazones behaving as binegative donors and acetohydroxamate acting as a mononegative ligand. The complexes function as effective olefin epoxidation catalysts.
- Zou,Sun,Chen
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- Synthesis, crystal structures and catalytic activity of oxidovanadium(V) complexes with tridentate ONO aroylhydrazone ligands
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Two oxidovanadium(V) complexes, [VOL1(OEt)] (1) and [V2O2(L2)2(OEt)2] (2), where L1 and L2 are the anions of 2-amino-N′-(2-hydroxybenzylidene)benzohydrazide (H2L1) and N′-(2-hydroxybenzylidene)-4-hydroxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1H NMR spectra. Structures of the complexes were further confirmed by single-crystal X-ray determination. The V atom in the mononuclear complex 1 is in square pyramidal coordination, and those in the dinuclear complex 2 are in octahedral coordination. Both aroylhydrazone ligands coordinate to the V atoms through the phenolate O, imino N, and enolate O atoms. The ethanol ligand in complex 1 is in terminal coordination mode, while that in complex 2 is in bridging coordination mode. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.
- Liang, Min,Zou, Dong-Hui,Chen, Wei,Kan, Wei,Tian, Zhi-Ming
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- Genesis and metabolisation of 1-pentene during lipid peroxidation of ω-6 unsaturated fatty acids: Metabolism of 1-pentene
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1-Pentene is generated by decomposition of ω-6 unsaturated fatty acid hydroperoxides. It is transformed under physiological conditions in presence of plant or mammalian liver enzymes to 1-pentene epoxide which can be trapped by reaction with thiophenol. The reaction products were identified by-comparing their mass spectra with those of authentic material.
- Scheick,Spiteller
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- Synthesis, Characterization and Crystal Structures of Oxidovanadium(V) and Dioxidomolybdenum(VI) Complexes Derived from 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide with Catalytic Property
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Abstract: A hydrazone compound 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (H2L) was prepared and characterized by IR, UV-Vis and NMR spectra. Based on the hydrazone compound, a new oxidovanadium(V) and a new dioxidomolybdenum(VI) complexes, [VO(L)(OEt)(EtOH)] (I) and [MoO2(L)(OH2)] (II), were prepared and characterized by IR, UV-Vis, NMR spectra, and single crystal X-ray diffraction (CIF files nos. 1866755 (I) and 1866756 (II)). Complex I crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 12.8733(12), b = 13.5088(13), c = 11.9262(11) ?, β = 91.765(2)°, V = 2073.0(3) ?3, Z = 4, R1 = 0.0524, wR2 = 0.1329, GOOF = 1.245. Complex II crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 8.1140(9), b = 16.2975(19), c = 13.4318(15) ?, β = 106.456(2)°, V = 1703.4(3) ?3, Z = 4, R1 = 0.0296, wR2 = 0.0728, GOOF = 1.046. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zou,Yang,Ye,Yang
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- Synthesis, structure, and catalytic oxidation of a molybdenum(VI) complex [MoO2(CH3OH)L]
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A new molybdenum(VI) complex, [MoO2(CH3OH)(L)] (L = N′-(4-diethylamino-2-hydroxybenzylidene)-4-hydroxybenzohydrazide), was prepared and characterized by spectroscopy methods and single crystal X-ray diffraction (CIF file CCDC no. 1038153). The crystal of the complex, C19H23MoN3O6, crystallizes in the triclinic space group P1 with unit cell dimensions a = 6.9824(9), b = 10.206(1), c = 15.302(2) ?, α = 94.399(2)°, β = 101.877(2)°, γ = 104.062(2)°, V = 1025.9(2) ?3, Z = 2, R1 = 0.0317, wR2 = 0.0796, S = 1.060. The Mo atom in the complex is in an octahedral coordination with phenolate O, imino N, enolate O atoms of the ligand L, and one oxo O in the equatorial plane, and with one methanol O and the other oxo O in the axial sites. Crystals of the complex are stabilized by hydrogen bonds. The complex was studied for its catalytic oxidation property on some olefins, with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zang,Lv
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- Synthesis and structures of two molybdenum(VI) complexes derived from similar benzohydrazone ligands with catalytic properties
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Two new structurally similar molybdenum(VI) complexes, [MoO 2L1(CH3OH)] (1) and [MoO2L 2(CH3OH)] (2), where L1 is the dianionic form of N′-(2-hydroxy-5-nitrobenzylidene)-2-methylbenzohydrazide and L 2 is the dianionic form of N′-(2-hydroxy-4-methoxybenzylidene)- 2-methylbenzohydrazide, were prepared and structurally characterized by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 7.941(1), b = 14.337(2), c = 15.141(2) A, β = 92.782(2)°, V = 1721.8(4) A3, Z = 4, R1 = 0.0286, wR2 = 0.0650, GOOF = 1.028. 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 8.003(1), b = 10.608(1), c = 10.880(1) A, α = 95.745(2)°, β = 97.627(2)°, γ = 105.762(2)°, V = 872.0(2) A3, Z = 2, R1 = 0.0226, wR2 = 0.0595, GOOF = 1.116. X-ray analysis indicates that Mo in the complexes are coordinated by the phenolate oxygen, imino nitrogen, and enolate oxygen of the benzohydrazone, methanol, and two oxo groups, generating octahedral coordination. The oxidation of olefins with the complexes as catalysts was evaluated, indicating that the complexes showed excellent catalytic efficiency in oxidation of most aliphatic and aromatic substrates under mild conditions using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
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- MoO3@SiO2 nanoreactors: Synthesis with a thermal decomposition strategy and catalysis on alkenes epoxidation
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A general thermal decomposition strategy is reported to fabricate MoO3@SiO2 nanoreactors, with a mesoporous silica shell and embedded MoO3 nanoparticles. The novel preparation procedure involves mixing certain mass ratio o
- Shen, Yirui,Jiang, Pingping,Wang, Yingchun,Bian, Gang,Wai, Phyu Thin,Dong, Yuming
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- Dissociation of Positively Charged Aliphatic Epoxides. II. +. Epoxides and α,β Unsaturated Ethers
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The unimolecular dissociations of C5 epoxides ions mono- or disubstituted at C1 give exclusive loss of CH3 and exclusive formation of methoxyvinyl carbenium ion, both in the source and in the 2nd field-free region.In the case of the 1,2-disubstituted ion in the 2nd field-free region the loss of ethene is the only pathway, while a competition occurs for the trisubstituted ion leading to +. and +. ions, the structure of which are demonstrated.The first step of the different mechanisms is the cleavage of the heterocyclic C-C bond.
- Bouchoux, Guy,Djazi, Feycal,Hoppilliard, Yannik,Jaudon, Pascale,Nouts, Nathalie
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- Epoxidation of terminal or electron-deficient olefins with H2O2, catalysed by Mn-trimethyltriazacyclonane complexes in the presence of an oxalate buffer
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A catalytic amount of an oxalate/oxalic acid buffer strongly enhances the catalytic properties of Mn-tmtacn complexes for epoxidation reactions with H2O2. Especially terminal olefins are easily epoxidized. Yields for e.g. allyl acetate or 1-hexene reach up to 99 % and 65 % on olefin and peroxide basis respectively. The reaction is stereospecific; there are no products of solvolysis.
- De Vos, Dirk E.,Sels, Bert F.,Reynaers, Mattias,Subba Rao,Jacobs, Pierre A.
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- Highly selective 1-pentene epoxidation over Ti-MWW with modified microenvironment of Ti active sites
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A titanosilicate/H2O2catalytic system was applied to process the liquid-phase selective epoxidation of 1-pentene to 1,2-epoxypentane (EP). The effects of titanosilicate topology (MWW, MFI, MSE, MEL, MOR, and *BEA), solvent, H2O/H2O2ratio, catalyst amount, reaction temperature, pressure, and time on the EP production were investigated systematically. The Ti-MWW/H2O2/acetonitrile system exhibited the highest 1-pentene conversion of 72.9% together with high EP selectivity of 99.9% and H2O2utilization efficiency of 91.5%. Moreover, it was proved that the Ti active sites located inside the intralayer 10-membered ring sinusoidal channels catalyzed the epoxidation process primarily owing to their supplying more steric fitness for 1-pentene molecules. A piperidine (PI)-assisted structural rearrangement of Ti-MWW was performed to further enhance the catalytic activity, almost doubling the turnover number value. The evolution of the microenvironment of Ti active sites in this structural rearrangement process was carefully investigated, revealing the coordination of N atoms in PI molecules to the Ti atoms. More importantly, we identified that the hexa-coordinated Ti sites with the PI molecules as ligand could significantly accelerate H2O2activation, the effect of which far exceeded the inhibition effect caused by the electronegativity increase of Ti active sites.
- Jiang, Jingang,Tian, Wenwen,Wang, Bowen,Wu, Peng,Xu, Hao,Yin, Jianyong,Yin, Jinpeng
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- Immobilization of molybdenum-based complexes on dendrimer-functionalized graphene oxide and their catalytic activity for the epoxidation of alkenes
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Two novel molybdenum-based heterogeneous catalysts immobilized on dendrimer-functionalized graphene oxide via electrostatic interactions (Mo-1) or covalent bonding (Mo-2) are reported. The catalysts show excellent catalysis in epoxidation of alkenes with high conversion, better selectivity and good recyclability. The characteristics were identified by SEM, TEM (EDS-mapping), FT-IR, XRD, and XPS. The cause of the difference between the two catalysts is supported by DFT calculations.
- Cheng, Maosheng,Fan, Zhanfang,Lin, Bin,Liu, Yang,Liu, Yongqing
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- N′-(3-Bromo-2-hydroxybenzylidene)isonicotinohydrazide and its oxovanadium(V) complex: Synthesis, structures, and catalytic properties
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A new hydrazone N′-(3-bromo-2-hydroxybenzylidene)isonicotinohydrazide (H2L) and its oxovanadium(V) complex, [VOLL′]·2H2O (L′ = 2-hydroxybenzohydroxamate), were prepared and structurally characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. The hydrazone coordinates to V through the phenolate oxygen, imino nitrogen, and enolate oxygen. The hydroxamate coordinates to V through the carbonyl oxygen and deprotonated hydroxyl oxygen. Vanadium in the complex is octahedral. The oxidation of olefins with the complex as catalyst was evaluated, which indicated that the complex showed catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant.
- Xiong, Yan,Li, Wen-Hui
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- Regioselectivity and diasteroselectivity in Pt(II)-mediated "green" catalytic epoxidation of terminal alkenes with hydrogen peroxide: Mechanistic insight into a peculiar substrate selectivity
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Recently developed electron-poor Pt(II) catalyst 1 with the "green" oxidant 35% hydrogen peroxide displays high activity and complete substrate selectivity in the epoxidation of terminal alkenes because of stringent steric and electronic requirements. In the presence of isolated dienes bearing terminal and internal double bonds, epoxidation is completely regioselective toward the production of terminal epoxides. Insight into the mechanism is gained by means of a reaction progress kinetic analysis approach that underlines the peculiar role of 1 in activating both the alkene and H 2O2 in the rate-determining step providing a rare example of nucleophilic oxidation of alkenes by H2O2.
- Colladon, Marco,Scarso, Alessandro,Sgarbossa, Paolo,Michelin, Rino A.,Strukul, Giorgio
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- Synthesis of Cyclic Organic Carbonates from C3-C16 Epoxides
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Cyclic organic carbonates were prepared from epoxides (derivatives of C3-C16 olefins, C4 and C8 dienes, styrene; epichlorohydrin) in the presence of a catalytic system consisting of CoCl2 · 6H2O and dimethylformamide.
- Rybina,Srednev,Bobyleva
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- Tris-imidazolinium-based porous poly(ionic liquid)s as an efficient catalyst for decarboxylation of cyclic carbonate to epoxide
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A series of imidazolinium-based porous poly(ionic liquid)s (PILs) with different anions prepared by free-radical copolymerization of an arene-bridged tris-vinylimidazolium salt and divinylbenzene (DVB) were constructed. The as-prepared PILs were characterized by BET, SEM, TEM, TGA and Elemental Analysis (EA), and the results showed that they had plentiful ionic sites, and abundant and stable mesopores. In particular, the density of ionic sites and pore structure of PILs could be controlled by adjusting the content of DVB. Moreover, the PILs were used as efficient heterogeneous catalysts for the decarboxylation of cyclic carbonates to epoxides for the first time. Results showed that the catalytic activity of PILs was positively correlated with the nucleophilicity of the anions in PILs, and PDVB-[PhTVIM]Cl-1 with a chloride anion-enriched skeleton displayed the best catalytic performance. Without any solvent or cocatalyst, PDVB-[PhTVIM]Cl-1 achieved a TOF value of 108.1 h-1and the yield of butylene oxide of 89.6%, which was even better than the homogeneous IL-based catalysts (TOF value: 8.7 h-1) that had been previously reported. Meanwhile, PDVB-[PhTVIM]Cl-1 also exhibited excellent recyclability and substrate compatibility.
- Li, Yang,Wang, Liguo,Cao, Yan,Xu, Shuang,He, Peng,Li, Huiquan,Liu, Hui
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- Co-Condensation Assisted Preparation of MoVI Schiff Base Modified Mesoporous Silica Catalyst for Enhanced Epoxidation of Olefins
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An organic-inorganic catalyst was prepared by the reaction of p-salicylidine aminobenzoic acid with mesoporous silica modified with 3-chloropropyl groups. The hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) and 3-chloropropyltrimethoxysilane (CPTES) took place during the preparation process. MoO2(acac)2 was then introduced into the mesoporous silica functionalized with a Schiff base ligand. The structural properties of the prepared catalysts were investigated by a series of techniques, such as elemental analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption curves, and thermogravimetric analysis (TGA). The results demonstrated that the MoVI Schiff base complex was successfully tethered on the silica support, and the hexagonally ordered mesoporous structure of the SBA-15-type silica was well retained after the anchoring reaction. The heterogeneous catalyst showed good catalytic activities in the liquid-phase epoxidation of olefins with t-BuOOH as the oxygen source in 1,2-dichloroethane solvent at 80°C. Several important factors, including oxidant-to-substrate ratio, solvent, and catalyst reusability, were investigated. Under the optimum reaction conditions, using this heterogeneous catalyst for the cyclohexene epoxidation reaction, a high conversion of 97.20% and selectivity of >99% was achieved after 4h, while the catalytic activity nearly remained unchanged over four runs.
- Zhang, Jian,Jiang, Pingping,Shen, Yirui,Zhao, Guohu,Zhang, Weijie,Bian, Gang
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- Syntheses, crystal structures, and catalysis by polymeric dioxomolybdenum(VI) complexes with similar (iso)nicotinohydrazones
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Polymeric dioxomolybdenum(VI) complexes, [MoO2L]n(L= L1= N'-(2-hydroxybenzylidene) nicotinohydrazide for 1, L=L 2= N'-(2-hydroxy-5-methoxybenzylidene)isonicotinohydrazide for 2), were prepared and characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. Complex 1 crystallizes in the orthorhombic space group P212121with a=7.6568(4), b =11.6315(7), c = 15.2211(9)A, V= 1355.59(13) A3, Z = 4, R1= 0.0181, wR2= 0.0464, and S = 1.097. Complex 2 crystallizes in the monoclinic space group P21/n with a=11.2516(6), b=11.8134(7), c= 12.4371(6) A, β = 116.2210(10)°, V=1483.02(14) A3, Z= 4, R1= 0.0399, wR2= 0.0874, and S=1.096. X-ray analysis indicates that Mo in each complex is octahedral with two oxo groups and N2O2donor set of the nicotinohydrazone or isonicotinohydrazone. The complexes are efficient catalysts for oxidation of olefins.
- Xu, Wei-Xiu,Yuan, Yong-Mei,Li, Wen-Hui
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- Studies on Polyoxo- and Polyperoxo-metalates. Part 1. Tetrameric Heteropolyperoxotungstates and Heteropolyperoxomolybdates
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New heteropolyperoxometalates of the type R34> (3+) (en = ethane-1,2-diamine); X = P or As; M = Mo or W> have been characterized by IR, Raman and where appropriate 31P NMR spectroscopy.Epoxidation of cyclic and linear alkenes by these species with H2O2 as co-oxidant has been studied; 4>(3-) was found to be the most effective.The oxidation of alcohols by 4>(3-) with H2O2 has been investigated.
- Dengel, Andrew C.,Griffith, William P.,Parkin, Bernardeta C.
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- Vanadium(V) complexes with hydrazone and benzohydroxamate ligands: Synthesis, structures and catalytic epoxidation
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Two structurally similar vanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2), where L1 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide, L2 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)nicotinohydrazide, and L is benzohydroxamate, were prepared and characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 12.0262(7), b = 16.5629(9), c = 12.3449(8) A, β = 105.160(2)°, V = 2373.4(2) A3, Z = 4, R1 = 0.0376, wR2 = 0.0844, GOOF = 1.058; 2 crystallizes in the monoclinic space group P2 1/c, with unit cell dimensions a = 10.6439(7), b = 16.1968(9), c = 13.1108(8) A, β = 104.180(2)°, V = 2191.4(2) A3, Z = 4, R1 = 0.0521, wR2 = 0.1142, GOOF = 1.018. X-ray analysis indicates that vanadium in the complexes are coordinated by phenolate oxygen, imino nitrogen, and enolate oxygen of the hydrazone, two oxygens of the benzohydroxamate, and one oxo, generating octahedral coordination. Oxidations of olefins with the complexes as catalysts were evaluated. The complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
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- Dissociations of Positively Charged Aliphatic Epoxides. I. Structure Elucidation of the η-Cleavage Products
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Dissociative ionization of 1,2-epoxy n-alkanes gives rise to abundant + ions of structure +.This conclusions is drawn from metastable ion analysis and from collosional activation spectra.This fragmentation involves the C-C ring opening and a 1,4-H migration leading to the corresponding enol ether +. precursor of + fragment.The same isomerization scheme applies to 1,2-epoxy methyl substituted alkanes and 2,3-epoxy n-alkanes.
- Bouchoux, Guy,Hoppilliard, Yannik,Jaudon, Pascale
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- Lamellar porous mo-modified carbon nitride polymers photocatalytic epoxidation of olefins
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A lamellar porous Mo-modified carbon nitride polymers (CN-Mo) was successfully prepared by a simple bottom-up method, which involves molecule self-assembly by hydrogen bonding between uracil and melamine. Analysis Results of X-ray diffraction (XRD), scann
- Gu, Qian,Jiang, Ping Ping,Shen, Yirui,Zhang, Kai,Wai, Phyu Thin,Haryono, Agus
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- Synthesis, x-ray structural characterization, and catalytic property of binuclear oxidovanadium(V) complex with 2,4-dibromo-6-(5-methylamino-[1,3,4]thiadiazol-2-yl) phenol
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A novel binuclear oxidovanadium(V) complex [V2O2(μ-O)L2(OEt)2], where L is the deprotonated form of 2,4-dibromo-6-(5-methylamino-[1,3,4]thiadiazol-2-yl)phenol (HL), was prepared by the reaction of 2-(3,5-dibromo-2-hydroxybenzylidene)-N-methylhydrazinecarbothioamide (HL’) and VO(acac)2 in ethanol. The ligand L’ underwent a cyclization during the coordination, to form a new ligand L. Structure of the complex was characterized by physicochemical methods and single-crystal X-ray determination. Crystal of the complex crystallizes in hexagonal space group R-3, with a = b = 33.302(3) ?, c = 15.308(2) ?, α = β = 90°, γ = 120°, V = 14702(3) ?3, Z = 18, R1 = 0.0823, wR2 = 0.2064, S = 1.011. X-ray analysis indicates that the V atom in the complex is in an octahedral coordination environment, constructed by the phenolate O and thiadiazol N atoms of L, one oxido O atom, one bridging O atom, and one deprotonated ethanol O atom. The distance between the two V atoms is 3.365(1) ?. The complex has an effective catalytic property for the oxidation of several olefins.
- Lei, Yan,Yang, Qiwen
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- Synthesis, crystal structures, and catalytic properties of two oxidovanadium(V) complexes with tridentate Schiff bases
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Two new oxidovanadium(V) complexes, [VO2L1] (I) and [VO2L2] (II), where L1 and L2 are the deprotonated forms of 4-methyl-2-[(2-morpholin-4-ylethylimino)methyl]phenol (HL1) and 2-[(2-isopropylaminoethylimino) methyl]-4-trifluoromethoxyphenol (HL2), respectively, have been prepared and characterized by physico chemical methods and single crystal X-ray diffraction (CIF files CCDC nos. 1443671 (I), 1443672 (II)). The V atom in each complex is coordinated by the phenolate oxygen, imino nitrogen and amino nitrogen of the Schiff base ligand, and two oxo groups, forming trigonal-bipyramidal geometry. The oxidation of olefins with the complexes as catalyst was evaluated, which indicated that both complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates by using tert-butyl hydrogen peroxide as oxidant.
- Peng
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- Synthesis, X-Ray crystal structures and catalytic epoxidation of oxidovanadium(V) complexes with aroylhydrazone and ethyl maltolate ligands
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Two oxidovanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2) (L = ethyl maltolate), derived from the aroylhydrazones 4-bromo-N'-(2-hydroxy-5-methylbenzylidene)benzohydrazide (H2L1) and N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectroscopy. Structures of the complexes were further confirmed by single crystal X-ray determination. The V atoms in the complexes are coordinated by the ONO donor atoms of the aroylhydrazone ligand, OO donor atoms of the ethyl maltolate ligand, and one oxido O atom, forming octahedral coordination. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.
- Chen, Wei,Liang, Min,Zou, Dong-Hui
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p. 441 - 446
(2021/06/25)
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- Epoxidation of Olefins with Molecular Oxygen Over Layered Double Hydroxide Catalyst in the Presence of Benzaldehyde
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A Fe embedded MgAl layered double hydroxide (MgAlFe0.4-LDH) showed excellent performances in the epoxidation of various olefins with O2/benzaldehyde as oxidant at mild conditions. Under optimal conditions, the olefins including termi
- Liu, Ya,Xin, Yuwei,Zhang, Hong-yu,Zhang, Yuecheng,Zhao, Jiquan
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- Method for epoxidizing small-molecular olefin
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The invention relates to a micromolecular olefin epoxidation method, which is characterized by comprising the following steps: contacting micromolecular olefin, an organic peroxide and a titanium-silicon composite oxide under epoxidation reaction conditions of at least two reaction temperatures of A and B to obtain an alkylene oxide-containing product, wherein the A is 80-95 DEG C, the B is 100-120 DEG C, the titanium-silicon composite oxide is of an amorphous structure, is formed by aggregation of nano-particles and has mesopores in the range of 16-50 nm, the ratio of the volume of the mesopores to the total pore volume is larger than or equal to 80%, and the volume of the mesopores is larger than or equal to 0.5 cm/g. According to the method, the amorphous titanium-silicon-titanium-silicon composite oxide is taken as the catalyst, and at least two sections of conditions with different reaction temperatures are combined, so that compared with the prior art, the catalyst is stable in structure, low in cost, high in olefin epoxidation reaction activity and good in product selectivity.
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Paragraph 0184-0185; 0214-0215
(2021/06/06)
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- Oxidovanadium(V) and dioxidomolybdenum(VI) Complexes of N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide: Synthesis, characterization, crystal structures and catalytic property
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N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide (H2L) was used to prepare oxidovanadium(V) complex [VOL(OEt)(MeOH)] (1) and dioxidomolybdenum(VI) complex [MoO2L(OH2)]·[MoO2L(EtOH)] (2). The complexes were characterized by IR, UV-Vis, NMR spectroscopy, and single crystal X-ray diffraction. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydroperoxide as oxidant.
- Liu, Huan-Yu,Yang, Luo-Ju,Ye, Ya-Fang,Yin, Yi-Shu,Zou, Xiao-Ling
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p. 130 - 136
(2020/03/30)
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- Vanadyl β-tetrabromoporphyrin: Synthesis, crystal structure and its use as an efficient and selective catalyst for olefin epoxidation in aqueous medium
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We hereby report the synthesis, characterization and catalytic applications in the epoxidation of alkenes by a vanadyl porphyrin having bulky bromo substituents at the β-positions viz. vanandyltetrabromotetraphenylporphyrin (1). The synthesized porphyrin was characterized by various spectroscopic techniques like UV-visible, FT-IR, EPR, MALDI-TOF mass spectrometry and single crystal X-ray analysis. Porphyrin 1 has a nonplanar structure as indicated by its X-ray structure, DFT and electrochemical studies. 1 was analyzed for its catalytic application in the epoxidation of various alkenes. The catalytic reactions were carried out in CH3CN/H2O mixture in 3:1 (v/v) ratio. 1 displayed good efficiency in terms of mild reaction conditions, lower reaction temperature and minimal catalyst amount consumption. 1 exhibited excellent selectivity, high conversion efficiency and huge TOF (7600-9800 h-1) in a significantly low reaction time of 0.5 h. Catalyst 1 was regenerated at the end of various catalytic cycles making it reusable and industrially important.
- Dar, Tawseef Ahmad,Tomar, Reshu,Mian, Rasel Mohammad,Sankar, Muniappan,Maurya, Mannar Ram
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p. 10405 - 10413
(2019/04/10)
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- Synthesis, crystal structures and catalytic property of oxidovanadium(V) complexes with similar aroylhydrazones
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A pair of new oxidovanadium(V) complexes, [VOL1L]·EtOH (1) and [VOL2L]·EtOH (2) (L = acetohydroxamate), derived from the aroylhydrazones N’-(5-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2L1) and N’-(5-bro-mo-2-hydroxybenzylidene)-4-methylbenzohydrazide (H2L2), have been prepared and characterized by elemental analyses, FT-IR,1H and13C NMR spectroscopy and single-crystal structural X-ray diffraction. The complexes have octahedral structures in which the aroylhydrazone ligands behave as binegative donors. Single-crystal structure analyses reveal that the V centers are coordinated by the donor atoms of the aroylhydrazone ligands, the acetohydroxamate ligands and the oxido groups. Crystal structures of the complexes are stabilized by hydrogen bonds. The complexes function as effective olefin epoxidation catalysts.
- Liang, Min,Sun, Nan,Zou, Dong-Hui
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p. 964 - 969
(2019/02/15)
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- A dioxidomolybdenum(VI) complex of tridentate ONO aroylhydrazone ligand: Synthesis, crystal structure and catalytic activity
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A new dioxidomolybdenum complex with the formula [MoO2L(MeOH)], derived from the tridentate aroylhydrazone 2-amino-N?-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide (H2L), has been prepared and characterized by elemental analysis, FTIR, 1H NMR, and single-crystal structural X-ray diffraction. The complex has a distorted octahedral structure in which the aroylhydrazone ligand behaves as a binegative donor one, leaving the amino-N uncoordinated toward the metal center. Single-crystal structure analysis reveals that the Mo(VI) center is coordinated by the donor atoms of the binegative aroylhydrazone ligand, two oxido groups and one oxygen atom of a methanol ligand. Crystal of the complex is stabilized by hydrogen bonds. The complex functions as an effective olefin epoxidation catalyst with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a cocatalyst.
- Liang, Min,Zou, Dong-Hui
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p. 110 - 115
(2017/08/10)
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- Synthesis, crystal structure and catalytic activity of dioxidomolybdenum(VI) complex with tridentate ono aroylhydrazone ligand
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A novel dioxidomolybdenum complex, [MoO2L], derived from the tridentate aroylhydrazone 2-amino-N'-(2-hydroxy-3-methylbenzylidene)benzohydrazide (H2L), has been prepared and characterized by elemental analysis, FT-IR, 1H NMR, and single crystal structural X-ray diffraction. The complex has distorted square pyramidal structure in which the aroylhydrazone ligand behaves as a binegative donor, leaving the amino-N group uncoordinated towards the metal center. Single crystal structure analysis reveals that the Mo(VI) center is coordinated by the donor atoms of the binegative aroylhydrazone ligand and two oxido groups. Crystal structure of the complex is stabilized by hydrogen bonds. The complex functions as an effective olefin epoxidation catalyst with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.
- Liang, Min,Zou, Dong-Hui
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p. 180 - 185
(2016/03/19)
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- Preparation of 1,2-pentanediol through oxidative hydrolysis of alpha-amylene
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The invention provides a preparation method for 1,2-pentanediol. According to the method, 1,2-pentanediol is prepared from cyclopentene through epoxidation synthesis under the condition of normal pressure in the presence of an organic solvent and an auxiliary agent with a Ti-MCM-41 molecular sieve as a catalyst and hydrogen peroxide with a mass percentage of 25 to 50% as an oxidizing agent. The method is simple in process, low in production cost and high in a reaction conversion rate.
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Paragraph 0026
(2017/03/28)
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- Synthesis, x-ray structural characterization, and catalytic property of dioxomolybdenum(VI) Complexes with N-(3-Bromo-2-hydroxybenzylidene)-2- hydroxybenzohydrazide and N-(5-Chloro-2-hydroxybenzylidene)-4- nitrobenzohydrazide
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Two new dioxomolybdenum(VI) complexes [MoO2(Bhbz) (CH3OH)] (1) and [MoO2(Cnbz)(CH3OH)] (2) with the benzohydrazone ligands H2Bhbz and H2Cnbz derived from 5-chlorosalicylaldehyde with 4-nitrobenzohydrazide and 3-bromosalicylaldehyde with 2-hydroxybenzohydrazide, respectively, have been synthesized and structurally characterized by physicochemical methods and single crystal X-ray determination. The crystal of (1) crystallizes in triclinic space group P-1, with a = 8.0014(9), b = 9.6294(10), c = 11.4204(12) A, = 89.193(2), β = 87.833(2), γ = 89.110(2)°, V = 879.11(16) A3, Z = 2, R 1 = 0.0464, wR 2 = 0.1185, S = 1.051. The crystal of (2) crystallizes in monoclinic space group P21/c, with a = 7.4108(3), b = 18.7901(7), c = 12.6293(5) A, β = 104.4850(10)°, V = 1702.72(12) A3, Z = 4, R 1 = 0.0236, wR 2 = 0.0576, S = 1.061. X-ray analysis indicates that the structures of both complexes are similar to each other. The molybdenum atom in each complex is in an octahedral coordination environment, constructed by two oxo groups and NO2 donor set of the ligand, and one methanol O atom. The complexes have effective catalytic property for the oxidation of several olefins.
- Lei, Yan,Yang, Qiwen,Chen, Gangcai,Yang, Qingling
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p. 590 - 597
(2014/01/06)
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- Bioproduction of chiral epoxyalkanes using styrene monooxygenase from rhodococcus sp. ST-10 (RhSMO)
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We describe the enantioselective epoxidation of straight-chain aliphatic alkenes using a biocatalytic system containing styrene monooxygenase from Rhodococcus sp. ST-10 and alcohol dehydrogenase from Leifsonia sp. S749. The biocatalyzed enantiomeric epoxidation of 1-hexene to (S)-1,2-epoxyhexane (44.6 mM) using 2-propanol as the hydrogen donor was achieved under optimized conditions. The biocatalyst had broad substrate specificity for various aliphatic alkenes, including terminal, internal, unfunctionalized, and di- and tri-substituted alkenes. Here, we demonstrate that this biocatalytic system is suitable for the efficient production of enantioenriched (S)-epoxyalkanes.
- Toda, Hiroshi,Imae, Ryouta,Itoh, Nobuya
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p. 3443 - 3450
(2015/02/05)
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- Synthesis, x-ray crystal structure, and oxidation catalytic property of a dioxomolybdenum(VI) complex derived from 5-diethylamino-2-[(2-hydroxyethylimino) methyl]phenol
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A new dioxomolybdenum(VI) complex, [MoO2L(CH3OH)], where L is the dianion of 5-diethylamino-2-[(2-hydroxyethylimino) methyl]phenol, was prepared and structurally characterized by physicochemical and spectroscopic methods and single-crystal X-ray determination. The Mo atom in the complex is in octahedral coordination. The crystal of the complex is stabilized by hydrogen bonds. The complex functions as an effective olefin epoxidation catalyst with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a cocatalyst under air atmosphere at room temperature.
- Ding, Shao-Bing
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p. 877 - 881
(2013/05/22)
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- Syntheses, X-ray structures, and catalytic oxidations of dioxomolybdenum(VI) complexes with tridentate benzohydrazones
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Two new dioxomolybdenum(VI) complexes, [MoO2L 1(CH30H)]CH30H (1) and [MoO2L 2(CH30H)] (2), where L1 and L2 are dianionic forms of N'-(3-bromo-2-hydroxybenzylidene)-4-hydroxybenzohydrazide and N'-(2-hydroxybenzylidene)-2-hydroxy-3-methylbenzohydrazide, respectively, have been synthesized. The complexes have been characterized by elemental analyzes, IR spectra, molar conductance data, and single crystal X-ray determination. Mo in each complex is octahedral. The crystals of the complexes are stabilized by hydrogen bonds and weak π π stacking interactions. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as oxidant and sodium hydrogen carbonate as a co-catalyst at room temperature.
- He, Xiao-Qiang
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p. 966 - 976
(2013/07/28)
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- New binuclear double-stranded manganese helicates as catalysts for alkene epoxidation
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New binuclear double-stranded helicates were formed between manganese(ii) perchlorate and chiral phenyl- and polyphenyl-bridged oligopyridines; they are active catalysts for alkene epoxidation.
- Sham, Kiu-Chor,Yeung, Ho-Lun,Yiu, Shek-Man,Lau, Tai-Chu,Kwong, Hoi-Lun
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scheme or table
p. 9469 - 9471
(2011/01/10)
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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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- Reactivity and kinetic-mechanistic studies of regioselective reactions of rhodium porphyrins with unactivated olefins in water that form β-hydroxyalkyl complexes and conversion to ketones and epoxides
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This article reports on the selective oxidation of unactivated alkenes to ketones and epoxides through the intermediacy of β-hydroxyalkyl rhodium porphyrin complexes which are formed by reactions of terminal alkenes with tetra(p-sulfonatophenyl)porphyrin
- Zhang, Jiadi,Wayland, Bradford B.,Yun, Lin,Li, Shan,Fu, Xuefeng
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scheme or table
p. 477 - 483
(2010/04/04)
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- TS-1 zeolite microengineered reactors for 1-pentene epoxidation
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A zeolite-based microengineered reactor was fabricated and tested for 1-pentene epoxidation over titanium silicalite-1 (TS-1) catalyst, which has been selectively incorporated within the microreactor channel using a new synthesis procedure.
- Wan, Yu Shan Susanna,Chau, Joseph Lik Hang,Gavriilidis, Asterios,Yeung, King Lun
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p. 878 - 879
(2007/10/03)
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- The synthesis of 1-pentene oligomers
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Alpha olefin oligomers, obtained from the cationic oligomerisation with BF3/ROH, consist of a mixture of isomeric products that complicate the investigation and rational modification of this and other closely related oligomerisation processes.
- Crause, Chantelle,Van Heerden, Fanie R.
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- USING THE COMPARISON OF STERIC VERSUS ELECTRONIC EFFECTS TO INFER MECHANISTIC INFORMATION IN STEPWISE ELECTROPHILIC ADDITION REACTIONS INVOLVING THREE-MEMBERED CYCLIC INTERMEDIATES
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Correlations of IP's versus relative reactivities or formation constants of reactions of alkenes with ArSCl, MeCO3H, Ag(1+), or HgCl2 reveal that complexation reactions show steric dependence, that additions with the first step rate-determining are sterically independent, and that those with the second step rate-determining are sterically dependent.
- Nelson, Donna J.,Soundararajan, Raman
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p. 6207 - 6210
(2007/10/02)
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- Oxygenated alicyclic compounds
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The compounds of formula wherein symbol R represents a C1 -C3 alkyl radical and X a substituted cyclohexyloxy group of formula STR1 wherein index n stands for zero or one, the dashed lines indicate a single bond (n=1) or a double bond in position 2 (n=0) or 3 (n=1) and each of symbols R1 to R6 designates a hydrogen atom or a methyl radical, are new and can be conveniently utilized as perfuming and flavoring ingredients. They develop in particular woody-ambery notes.
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- The Transition Metal Catalyzed Nucleophilic Epoxide Ring Opening Reaction
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The catalytic influence of MoO2(acac)2, Mo(CO)6, MoCl5, WCl6 and TaCl5 on the reaction of 1,2-epoxy-octane with ethanol at 100 deg C in dioxan or chlorobenzene as solvents is proved.Water and hydroperoxides react with a higher rate than alcohols.When changing from primary to secondary and tertiary alcohols a decrease of the reaction rate is observed. 2,3- and 3,4-Epoxyheptane and cis- and trans-4,5-epoxy-octane react more slowly than the corresponding 1,2-epoxides.Epichlorhydrin and methylglycidether react with a lower, cyclohexene oxide, styrene oxide and norbornene oxide react with a higher rate than 1,2-epoxyoctane.The reactivities of the two dicyclopentadiene monoepoxides correspond with the reactivities of the norbornene and cyclopentene oxides.In the molybdenum catalyzed epoxide ring opening reaction an isomer distribution appears in favour of the 1-hydroxy-2-ethoxy-alkane 2.A mechanism in the coordination sphere of the transition metal complex is proposed.
- Lauterbach, G.,Posselt, G.,Schaefer, R.,Schnurpfeil, D.
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p. 101 - 120
(2007/10/02)
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- Addition of Pentenes to Slowly Reacting Mixtures of Hydrogen and Oxygen at 480 deg C
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A detailed analysis has been made of the products formed when 1percent of pent-1-ene and of cis-pent-2-ene are added to slowly reacting mixtures of H2 + O2 in aged boric-acid-coated vessels at 480 deg C.The primary products are formed through four different types of attack on the pentenes of almost equal importance, radical addition of H, OH, and HO2, and H atom abstraction from the pentenes by all three radicals.Penta-1,3-diene is the only C5 diene observed, in marked contrast to an earlier study of pentene oxidation.From measurements of the initial relative yields of penta-1,3-diene and buta-1,3-diene, a value of k2 = 2.1 x 1E6 dm3 mol-1 s-1 at 480 deg C is obtained. This is the first value determined for a reaction of this type and is at least ten times lower than rate constants for the formation of an alkene from an alkyl radical.This decrease is consistent with the considerably lower enthalpy change in reaction (2).Product analysis suggests that H atoms add almost equally at the two positions in pent-2-ene, and in the ratio of 0.65 +/-0.2 for non-terminal/terminal addition in pent-1-ene.In contrast to the behaviour of vibrationally-excited propyl and butyl radicals formed by H atom addition to alkenes, there is no evidence for an enhanced rate of decomposition of the pentyl radicals formed from the pentenes.Conjugate oxirans are formed mainly by HO2 addition to the pentenes, and lower aldehydes mainly by OH addition.
- Baldwin, Roy R.,Bennett, Joan P.,Walker, Raymond W.
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p. 2396 - 2412
(2007/10/02)
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