Sharif Digital Repository

A heterogeneous catalyst for epoxidation of alkenes has been synthesized by introducing polyoxomolybdate into a natural zeolite as a solid and green support. The prepared catalyst was characterized by FT-IR, inductively coupled plasma optical emission spectrometry (ICP-OES), powder X-ray diffraction (XRD), N2 absorption–desorption, field emission scanning electron micrograph (FE-SEM) and transmission electron microscopy (TEM). The catalytic investigations disclosed that nanocluster polyoxomolybdate supported on the surface is an active and recyclable catalyst in liquid phase alkene epoxidation in dichloroethane at 80 °C. © 2017 Informa UK Limited, trading as Taylor & Francis Group  

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We report a facile method to synthesize a magnetically separable Pd-rGO/CNT/CaFe2O4 photocatalyst. The incorporation of CNTs into rGO can form a conductive network structure to bridge the gaps between rGO sheets. This conductive network can prevent the restacking of GO nanosheets during the reduction process. Also, for photocatalysis, the aforementioned conjugated network can provide rapid electronic conducting channels. It was found that the Pd-rGO/CNT/CaFe2O4 nanocomposite is an efficient photocatalyst for the Heck-Mizoroki coupling reaction under irradiation of visible light. Interestingly, the electrons which are excited by the photons can be transferred to the palladium nanoparticles... 

Palladium nanoparticles supported on polyoxometalate as a solid carrier were successfully prepared and evaluated as a heterogeneous nanocatalyst for the Mizoroki-Heck cross-coupling reactions. This supported catalyst was characterized by a set of techniques, including XRD, chemical analysis (ICP-OES), IR spectroscopy, TEM and FE-SEM analyses. Poly (ethylene glycol) was employed as an environmentally friendly solvent for coupling reactions. The various fundamental reaction parameters that influence the efficiency of the reaction and yield of the desired reaction products were optimized. This catalytic system showed good activities and evolve a strategy for achieving five times catalyst and... 

Graphene oxide was an effective supporting material for immobilizing a dioxomolybdenum Schiff base complex via covalent interaction. The large surface of graphene oxide plays important roles to obtain a good degree of catalytic reaction. Catalytic capacity of the graphene-bound dioxomolybdenum Schiff base complex was investigated for the oxidation of various sulfides to sulfoxide compounds using hydrogen peroxide urea as an oxidant. The catalyst was characterized by various techniques including XRD, FTIR, TGA, SEM, UV–vis, and ICP-AES. The immobilized complex was very efficient with the extra benefits of easy recovery and recycling of the heterogeneous catalyst. The graphene oxide bound... 

We report a facile method to synthesize a magnetically separable Pd-rGO/CNT/CaFe2O4 photocatalyst. The incorporation of CNTs into rGO can form a conductive network structure to bridge the gaps between rGO sheets. This conductive network can prevent the restacking of GO nanosheets during the reduction process. Also, for photocatalysis, the aforementioned conjugated network can provide rapid electronic conducting channels. It was found that the Pd-rGO/CNT/CaFe2O4 nanocomposite is an efficient photocatalyst for the Heck-Mizoroki coupling reaction under irradiation of visible light. Interestingly, the electrons which are excited by the photons can be transferred to the palladium nanoparticles... 

A novel binuclear Mn(II) complex based on a para-nitro substituted amidic ligand (N-(4-nitrophenyl)picolinamide) has been synthesized and characterized by X-ray crystallography. This complex shows a high degree of conversion and epoxide selectivity in Mukaiyama aerobic epoxidation reactions of cyclic olefins in mild conditions  

The reaction of the functionalized mesoporous SBA-15 in absolute ethanol with copper (II) acetate afforded a novel CuII-Schiff base/SBA-15 catalyst. The compound CuII-Schiff base/SBA-15 was characterized by IR spectroscopy, small-angle X-ray diffraction (SAX), Energy Dispersive X-ray Spectroscopy (EDXS), X-ray Absorption Near Edge Structure (XANES), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and N2 adsorption/desorption studies. Further, the catalytic activity of this well-defined material was tested in three-component Copper-catalyzed Azide-Alkyne Cycloaddition (CuAAC) reactions to obtain 1,4-disubstituted-1,2,3-triazoles in good to excellent yields from an... 

In the present research, iron oxide nanoparticles were synthesized through the hydrothermal method, and the influence of processing parameters such as pH of the initial coprecipitation reaction, time and temperature of hydrothermal treatment was studied. The magnetic iron oxide nanoparticles were coated with a negatively charged, thin layer of silica. The product is then coated with a layer of mesoporous silica. As a result of the electrostatic attraction between the cationic CTAB and the primary silica coating, the formation of mesoporous silica would be mainly localized on the surface of nanoparticles. Calcination was performed in an argon atmosphere tube furnace at 550 °C, through which... 

The reaction between [MoO2(acac)2] and an ONO type Schiff-base ligand (L = 4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol) resulted a new oligomer molybdenum complex ([MoO2(L)]n). The oligomer complex was characterized by elemental analysis, FT-IR, 1H and 13C NMR spectroscopies. A suitable single crystal of the complex was grown in DMSO and characterized by X-ray single crystal diffraction as monomer stabilized by one DMSO molecule, [MoO2L(DMSO)]. The [MoO2(L)]n complex was used as a catalyst in epoxidation of olefins. Besides the high activity and selectivity, very high turnover numbers were a remarkable advantage of the catalytic system. © 2017  

Vanadium supported on spinel cobalt ferrite nanoparticles was synthesized and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis and transmission electron microscopy. For the first time, the prepared material was used for the catalytic degradation of methylene blue as an organic dye in the presence of hydrogen peroxide as a green oxidant and NaHCO3 as a co-reagent at room temperature. The dependency of removal percentage on various parameters such as amount of catalyst, pH, reaction time and temperature and the effect of radical scavenging agents were studied. Finally, recoverability and reusability of the vanadium supported on... 

A heterogeneous nanocatalyst containing polyoxomolybdate immobilized on the internal surface of amino-functionalized SBA-15 pores was prepared and fully characterized by several analytical techniques. The textural property of supported material was found to retain important mesoporous features, compatible with its potential use as heterogeneous catalysts. The catalyst SBA-15-NH3+•{Mo36}–shows excellent catalytic activity for the epoxidation of alkenes as compared to POM, which is attributed to the large specific surface area and highly ordered pore structure of SBA-15, allowing for easy access of reactants to the active sites and removal of products. The prepared catalyst has high... 

Although CO2 injection significantly increases the amount of oil recovered, it can cause asphaltene deposition in oil reservoirs. Asphaltene deposition leads to formation damage, in which treatment is a costly and problematic operation. In this work, impact of asphaltene precipitation and deposition during CO2 injection are investigated for recombined oil both in sandstone and carbonate core samples through dynamic flow experiments. Injection of oil and CO2 was performed simultaneously. Then, pressure drops along the core were recorded continuously to estimate permeability reductions during the experiments. Online viscosity of injected fluid was measured by a designed capillary viscometer.... 

Metal–organic frameworks (MOFs) are best known for their great structural diversity. The uniformity in the properties of MOFs is mainly governed by the size and morphology of the particles. In the present research, iron-MIL-88A was prepared by a modulator-assisted solvothermal method, and the role of modulating agents in the formation process of MOF particles was investigated. Acetic acid and formic acid were chosen as monoligand modulating agents. The changes in morphology and size distribution of the products were scrutinized by using SEM micrographs. Both modulators clearly interfered with the crystallization process through their attachment to the reactive sites. At low modulator... 

A molybdenum complex was immobilized on Schiff-base-modified magnetic and non-magnetic particles by covalent linkage. The characterizations of the obtained materials were carried out by means of TG–DTG, SEM, TEM, VSM, XPS, IR, and Raman microprobe techniques. All of them exhibited efficient activities in the oxidation of sulfides to sulfoxides by urea hydrogen peroxide oxidant. The advantages and disadvantages of these catalysts are discussed in detail. Molybdenum complex immobilized on silica bead can be recycled and recovered by simple filtration, but it demonstrated low activity in catalytic oxidation reaction. Immobilization on nano-SiO 2 leads to the formation of nanocatalyst having... 

A magnetic vanadium oxide nanoparticles supported on spinel copper ferrite (CuFe2O4–VOx) are prepared, characterized, and examined for the peroxymonosulfate (PMS) activation to degrade Rhodamine B (RhB) in water solution. Interestingly, the results show that despite the inability of mixture of copper ferrite and vanadium oxides nanoparticles to the effective RhB decomposition, the prepared catalyst exhibits an excellent catalytic ability toward RhB oxidation. The influence of vital parameters, such as temperature, PMS concentration, catalyst loading, and initial pH are discussed comprehensively. The kinetic studies demonstrate that the pseudo-first-order model is well fitted for RhB... 

Two new potentially heptadentate N4O3 Schiff base ligands {N[(CH2)3NCH(2-OH-3,5-t-Bu2C 6H2)]3} (H3L1) and {N[(CH2)3NCH(2-OH-3,5-t-Bu2C6H 2)]2 [(CH2)2-NCH(2-OH-3,5-t-Bu 2C6H2)]} (H3L2) were synthesized and characterized by various spectroscopic methods. The heptadentate N4O3 Schiff bases, H3L1 and H 3L2, were derived from the condensation reaction of two tripodal tetraamine ligands, tris(3-aminopropyl)amine and (2-aminoethyl)-bis(3- aminopropyl)amine with 3 equiv. of 3,5-di-tert-butylsalicylaldehyde, respectively. The neutral gadolinium(III) and samarium(III) complexes, [Ln(L)], of these bulky ligands and also a gadolinium(III) complex of a previously known ligand,... 

The potentiometric response characteristics with respect to salicylate anion of several membrane electrodes based on iron(II) tetraphenylporphyrin chloride (FeTPPCl) and derivatives with electrophilic and nucleophilic substituents, incorporated into plasticized polyvinylchloride (PVC) membranes were investigated. Complexes tetraphenyl porphyrin iron(III) chloride (FeTPPCl; A), tetrakis (4-methoxyphenyl) porphyrin iron(III) chloride (Fe(TOCH 3PP)Cl; B), tetrakis (2,6-dichlorophenyl) porphyrin iron(III) chloride (Fe(TDClPP)Cl; C), tetrakis (4-nitrophenyl) porphyrin iron(III) chloride (Fe(TNO2PP)Cl; D), and tetrakis (pentafluorophenyl) porphyrin iron(III) chloride (Fe(TPFPP)Cl; E) were used as... 

The multistep release of therapeutic agents in the theranostic particulate systems has remained as a challenge in smart drug delivery. In this study, superparamagnetic nanoparticles of Fe3O4 were coated with a blend of F127/F68 grades of pluronic in order to adjust the lower critical solution temperature (LCST) and consequently engineering of the release temperature. Pluronic as a biocompatible thermo-sensitive polymer is frequently used as a self-emulsifying drug delivery system. Magnetite nanoparticles with double layer coating of oleic acid and pluronic F127 have been reported as an on-demand smart carrier for hydrophobic drugs. LCST was examined using differential scanning calorimetry...