844874-18-6Relevant academic research and scientific papers
Tin incorporated periodic mesoporous organosilicas (Sn-PMOs): Synthesis, characterization, and catalytic activity in the epoxidation reaction of olefins
Sisodiya, Sheetal,Shylesh,Singh
, p. 629 - 633 (2011)
Tin incorporated mesoporous organosilicas (Sn-PMO) having uniform hexagonal arrangements were prepared using alkyl trimethylammonium bromide surfactants under basic reaction conditions. Characterization techniques revealed that the structural ordering, morphology, and the percentage of tin incorporation depend critically on the hydrophobic chain length of surfactants. The Sn-PMO samples are thermally stable up to 500 °C under air atmosphere and were hydrothermally stable up to 100 h in boiling water. The organotinsilicates showed excellent catalytic activity and reusability in the epoxidation of norbornene and cis-cyclooctene than an Sn-MCM-41 due to organic groups in the frame wall positions and the better accessibility of reactants to the active sites.
Halogenated tetraphenyl porphyrin; Iodosylbenzene an efficient catalytic system for olefin epoxidation
Aggrawal, Dau D.,Bhat, Daisy
, p. 1123 - 1129 (2016/01/15)
Olefin epoxidation using o-phenyl and b-pyrrole substituted tetraphenyl porphyrin complexes of Fe(III) and Mn(III) as catalysts and yIodosylbenzene as oxidant was studied. Excellent yields of epoxide and secondary oxidation products were observed. Effect of pyridine, imadizole, sodium lauryl sulphate, and solvent variation was also studied. Effect of substituents on catalytic activity of the porphyrin complex is also explained. o-phenyl substituted complexes gave better yield of epoxide as compared to b-pyrrole substituted complexes.
A heterogenized vanadium oxo-aroylhydrazone catalyst for efficient and selective oxidation of hydrocarbons with hydrogen peroxide
Monfared, Hassan Hosseini,Abbasi, Vahideh,Rezaei, Adineh,Ghorbanloo, Massomeh,Aghaei, Alireza
experimental part, p. 85 - 92 (2012/08/28)
A hydrazone Schiff base ligand derived from salicylaldehyde and benzhydrazide has been synthesized and reacted with vanadium(IV) leading to the corresponding vanadium(V) complex. The complex has been anchored on the surface of functionalized silica gel by N,O-coordination to the covalently Si-O bound modified salicylaldiminato ligand. The supported complex has been evaluated as a catalyst for hydrocarbon oxidation with hydrogen peroxide in acetonitrile. The heterogeneous system proved to be an efficient catalyst and was able to activate hydrogen peroxide toward the oxidation of alkenes, alkanes, benzene, and alkylaromatic compounds with more than 2,500 h-1 activity. Springer Science+Business Media B.V. 2011.
The catalytic function of a silica gel-immobilized Mn(II)-hydrazide complex for alkene epoxidation with H2O2
Ghorbanloo, Massomeh,Monfared, Hassan Hosseini,Janiak, Christoph
experimental part, p. 12 - 20 (2011/10/05)
An efficient and highly selective heterogeneous catalyst was developed by immobilization of a manganese complex on an inorganic support to yield (silica gel)-O2(EtO)Si-L1-Mn(HL2) [(L1) - modified salicylaldiminato and H2L2(E)- N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide]. Mn(II) has been anchored on the surface of functionalized silica by means of N,O-coordination to the covalently Si-O bound modified salicylaldiminato Schiff base ligand. The prepared material (silica gel)-O2(EtO)Si-L1-Mn(HL 2), was characterized by elemental and thermogravimetric analyses (TGA and DTA), UV-vis and FT-IR spectroscopy. This new material is demonstrated to be a very active catalyst in clean epoxidation reactions using a combined oxidant of aqueous hydrogen peroxide and actonitrile in the presence of aqueous sodium hydrogencarbonate. The effects of reaction parameters such as solvent, NaHCO3 and oxidant in the epoxidation of cis-cyclooctene were investigated. Cycloalkenes were oxidized efficiently to their corresponding epoxide with 87-100% selectivity in the presence of this catalyst. This catalytic system showed also good activities in the epoxidation of linear alkenes. The obtained results show that this catalyst is a robust and stable heterogeneous catalyst which can be recovered quantitatively by simple filtration and reused multiple times without loss of its activity.
Homogeneous green catalysts for olefin oxidation by mono oxovanadium(V) complexes of hydrazone Schiff base ligands
Monfared, Hassan Hosseini,Bikas, Rahman,Mayer, Peter
experimental part, p. 2574 - 2583 (2011/02/17)
Three mono oxovanadium(V) complexes of tridentate Schiff base ligands [VO(OMe)L'] (1), [VO(OMe)L2] (2) and [VO(OMe)L3] (3) obtained by monocondensation of 3-hydroxy-2-naphthohydrazide and aromatic o-hydroxyaldehydes have been synthesized (H2L2 - (E)-3-hydroxy-N′-(2-hydroxy-3-methoxybenzylidene)-2-naphthohydrazide, H2L2 - (E)-3-hydroxy-N′-(2-hydroxybenzylidene)-2- naphthohydrazide and H2L3 - (E)-N′-(5-bromo-2- hydroxybenzylidene)-3-hydroxy-2-naphthohydrazide). The complexes were characterized by spectroscopic methods in the solid state (IR) and in solution (UV-Vis, 1H NMR). Single crystal X-ray analyses were performed with 1 and 2. The catalytic potential of these complexes has been tested for the oxidation of cyclooctene using H2O2 as the terminal oxidant. The effects of various parameters including the molar ratio of oxidant to substrate, the temperature, and the solvent have been studied. The catalyst 2 showed the most powerful catalytic activity in oxidation of various terminal, cyclic and phenyl substituted olefins. Excellent conversions have been obtained for the oxidation of cyclic and bicyclic olefins.
Olefin epoxidation with H2O2 in the presence of Mn(II) dicarboxylate coordination polymer catalysts
Hosseini Monfared, Hassan,Mohajeri, Azar,Morsali, Ali,Janiak, Christoph
experimental part, p. 1437 - 1445 (2010/08/05)
The Mn(II) dicarboxylate coordination polymers [Mn(μ-terephthalate) (H2O)2] n, [Mn(μ-oxalate)(H 2O)2] n, and [Mn(μ-d-(-)-tartrate)] n were prepared in water and characterized by FT-IR spectroscopy and CHN analysis. Particles of the terephthalate catalyst were also synthesized, by reaction of terephthalic acid and MnCl2?4H2O by a sonochemical method. The catalytic potential of these coordination polymers as slow-release sources of catalytically active Mn species was tested in the oxidation of cyclooctene to its epoxide in acetonitrile, using hydrogen peroxide as oxygen source. For the terephthalate species the catalytic activity was found to increase with increasing dielectric constant and dipole moment of the solvent (being highest in acetonitrile), with reaction temperature to a maximum at 60 °C, and with an imidazole co-catalyst (highest activity found for a imidazole-to-catalyst molar ratio of 20:1). Good activity with more than 64% conversion in 24 h was obtained for epoxidation of cyclooctene and cyclohexene, whereas low yields only were obtained from aryl-substituted olefins. Some exo versus endo regioselectivity was found for norbornene.
[γ-1,2-H2SiV2W10O40] immobilized on surface-modified SiO2 as a heterogeneous catalyst for liquid-phase oxidation with H2O2
Kasai, Jun,Nakagawa, Yoshinao,Uchida, Sayaka,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 4176 - 4184 (2007/10/03)
An organic-inorganic hybrid support has been synthesized by covalently anchoring an N-octyldihydroimidazolium cation fragment onto SiO2 (denoted as 1-SiO2). This modified support was characterized by solid-state 13C, 29Si, and 31P NMR spectroscopy, IR spectroscopy, and elemental analysis. The results showed that the structure of the dihydroimidazolium skeleton is preserved on the surface of SiO2. The modified support can act as a good anion exchanger, which allows the catalytically active polyoxometalate anion [γ-1,2-H 2SiV2W10O40]4- (I) to be immobilized onto the support by a stoichiometric anion exchange (denoted as I/1-SiO2). The structure of anion I is preserved after the anion exchange, as confirmed by IR and 51V NMR spectroscopy. The catalytic performance for the oxidation of olefins and sulfides, with hydrogen peroxide (only one equivalent with respect to substrate) as the sole oxidant, was investigated with I/1-SiO2. This supported catalyst shows a high stereospecificity, diastereoselectivity, regioselectivity, and a high efficiency of hydrogen peroxide utilization for the oxidation of various olefins and sulfides without any loss of the intrinsic catalytic nature of the corresponding homogeneous analogue of I (i.e., the tetra-n-butylammonium salt of I, TBA-I), although the rates decreased to about half that with TBA-I. The oxidation can be stopped immediately by removal of the solid catalyst, and vanadium and tungsten species' can hardly be found in the filtrate after removal of the catalyst. These results rule out any contribution to the observed catalysis from vanadium and tungsten species that leach into the reaction solution, which means that the observed catalysis is truly heterogeneous in nature. In addition, the catalyst is reusable for both epoxidation and sulfoxidation without any loss of catalytic performance.
Immobilization of a Metal Complex in Y-Zeolite Matrix: Synthesis, X-ray Single-Crystal, and Catalytic Activities of a Copper (Schiff-Base)-Y Zeolite Based Hybrid Catalyst
Saha, Pratap Kumar,Banerjee, Surajit,Saha, Sandip,Mukherjee, Alok Kumar,Sivasanker, Subramanian,Koner, Subratanath
, p. 709 - 714 (2007/10/03)
A new zeolite-immobilized copper(II) complex catalyst has been prepared by entrapping [CuL] [LH2 = N,N′ -(1,1-dimethylethylene)bis(salicylaldiimine)] on NaY zeolite matrix. The reaction of Cu-NaY and molten LH2 affords a green mass of crude catalyst that upon a treatment with CH3CN gives a gray-colored hybrid catalyst (CuL-NaY). The prepared catalyst has been characterized by IR and UV-vis spectroscopic and EPR spectrometric measurements, TG-DTA analysis, powder X-ray diffraction, and surface-area measurements. To ascertain the structure of the immobilized complex, a single-crystal X-ray diffraction analysis of [CuL] was performed. Spectroscopic measurements showed that the green crude of CuL-NaY contains a penta- or hexa-coordinated copper(II) moiety, while the CuL-NaY catalyst contains a distorted square-planar [CuL] complex moiety. A remarkable catalytic activity of the prepared hybrid catalyst has been observed in oxidation reactions of 1-naphthol and norbornene.
Environmentally friendly catalysis using supported reagents: Catalytic epoxidation with hydrogen peroxide mediated by iron(II) ions immobilised on γ-alumina
Monfared, Hassan Hosseini,Ghadimi, Mitra
, p. 313 - 314 (2007/10/03)
A simple heterogeneous catalyst based on supporting iron(II) ions on γ-alumina was developed and successfully applied to the selective epoxidation of olefins with 35% aqueous H2O2 as an oxygen donor in CH3CN.
Alkane oxidation with manganese substituted polyoxometalates in aqueous media with ozone and the intermediacy of manganese ozonide species
Neumann, Ronny,Khenkin, Alexander M.
, p. 1967 - 1968 (2007/10/03)
Manganese substituted polyoxometalates (POMs), such as Li12[MnII2ZnW(ZnW9O 34)2] were effective catalysts for the oxidation of alkanes to ketones with ozone in an aqueous reaction medium; a green intermediate compound observable by UV-VIS and ESR at -78 °C was postulated to be a reactive manganese ozonide species.
