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bagherzadeh-chehreh--b
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Flow control around a circular cylinder with swinging thin plates
, Article Journal of Fluids and Structures ; Volume 81 , 2018 , Pages 738-760 ; 08899746 (ISSN) ; Javadi, K ; Sharif University of Technology
Academic Press
2018
Abstract
Flow around a 2D circular cylinder with attached swinging thin splitter plates is numerically investigated. The ratio of the plates’ length to the cylinder diameter is 1 ([Formula presented]=1) where L is the Plates’ length and D is the cylinder diameter. The plates are attached at ±55 degrees (trigonometric angle) downstream and are forced to oscillate at different ratios of the natural vortex shedding frequencies with magnitudes of FR=0.75,1,1.25,1.5 and 2. The oscillation amplitude “α” as the other main variable ranges from 10 to 18 degrees. Two-dimensional simulations are carried out at the Reynolds number 100, and then extended to higher Reynolds number of 200. The results show that in...
Numerical Investigation of Vortex Shedding Control Behind a Cylinder with Swinging Thin Plates
, M.Sc. Thesis Sharif University of Technology ; Javadi, Khodayar (Supervisor) ; Tayyebi Rahni, Mohammad (Co-Advisor)
Abstract
Von-Karman vortex shedding is a transient aerodynamic instability which occurs in laminar flows over a bluff body in a certain condition. When this phenomenon occurs, vortices take form on upper and lower parts of the bluff body and begin to shed into an oscillatory manner affecting a significant part of the flow domain. This research focuses on Karman vortex shedding control by using two thin oscillating splitter plates. Length ratio of plates to cylinder diameter is 1 (L⁄D=1) and plates are attached at ±55 degrees (trigonometric angle). Plates are forced to oscillate at different ratios of natural vortex shedding frequencies (0.75, 1, 1.25, 1.5 and 2) for diffenet amplitudes. Simulations...
Nano-layered manganese oxides as low-cost, easily synthesized, environmentally friendly and efficient catalysts for epoxidation of olefins
, Article RSC Advances ; Volume 2, Issue 9 , 2012 , Pages 3654-3657 ; 20462069 (ISSN) ; Najafpour, M. M ; Nayeri, S ; Pashaei, B ; Bagherzadeh, M ; Sharif University of Technology
2012
Abstract
Incorporation of calcium(ii), zinc(ii) and aluminium(iii) to manganese oxides greatly improved the activity of manganese oxide towards the epoxidation of olefins in the presence of anhydrous tert-butyl hydroperoxide as an oxidant
New molybdenum(VI) complex with ONS-donor thiosemicarbazone ligand: Preparation, structural characterization, and catalytic applications in olefin epoxidation
, Article Inorganic Chemistry Communications ; Volume 27 , 2013 , Pages 26-30 ; 13877003 (ISSN) ; Boghaei, D. M ; Amini, M ; Bagherzadeh, M ; Notash, B ; Sharif University of Technology
2013
Abstract
New dioxomolybdenum(VI) complex was prepared by reacting 1-(2,4-dihydroxybenzylidene)-N-methyl-N-phenylthiosemicarbazone (H2L) as ligand and [MoO2(acac)2] in acetonitrile solution. The doubly deprotonated ligand is coordinated to molybdenum through sulfur atom, hydrazinic nitrogen atom and phenolic oxygen atom. The resulting complex with the formula [MoO2L(CH3CN)] which contains an acetonitrile molecule in sixth site of coordination, was characterized by elemental analyses, 1H NMR, IR and electronic spectroscopic studies and single crystal X-ray diffraction analysis. This complex was tested as a catalyst for the homogeneous epoxidation of olefins using tert-butyl hydrogen peroxide (TBHP) as...
Tris[(2-oxazolinyl)phenolato]manganese(III) as catalyst for mild and efficient oxidation of sulfides to sulfones with Oxone®
, Article Journal of Chemical Research - Part S ; Issue 12 , 2003 , Pages 765-767 ; 03082342 (ISSN) ; Sharif University of Technology
Scientific Reviews Ltd
2003
Abstract
Tris[(2-oxazolinyl)phenolato]manganese(III), Mn(phox)3, catalysed oxidation of dialkyl, diaryl, dibenzyl, and alkyl aryl sulfides to the corresponding sulfones is carried out by Oxone® in biphasic conditions (CH2Cl2/H2O), in the presence of tetra n-butylammonium bromide as phase transfer agent at room temperature in very short reaction times (5 min.) with quantitative yields
A new and highly effective method for catalytic oxidation of alcohols to the corresponding carbonyl compounds using the tris[(2-oxazolinyl)phenolato] manganese(III)/Oxone®/n-Bu4NBr oxidation system
, Article Tetrahedron Letters ; Volume 44, Issue 50 , 2003 , Pages 8943-8945 ; 00404039 (ISSN) ; Sharif University of Technology
Elsevier Ltd
2003
Abstract
Oxone® (2KHSO5·KHSO4·K 2SO4) in the presence of mer-tris[(2-oxazolinyl)phenolato] manganese(III), Mn(phox)3, as catalyst under biphasic reaction conditions (CH2Cl2/H2O) and tetra-n-butylammonium bromide as phase transfer agent efficiently oxidises alcohols to their corresponding aldehydes and ketones at room temperature with very short reaction times (5 min) and good to quantitative yields. © 2003 Elsevier Ltd. All rights reserved
Mn(III) complex supported on Fe3O4 nanoparticles: Magnetically separable nanocatalyst for selective oxidation of thiols to disulfides
, Article Journal of Coordination Chemistry ; Volume 66, Issue 17 , 2013 , Pages 3025-3036 ; 00958972 (ISSN) ; Haghdoost, M. M ; Moghaddam, F. M ; Foroushani, B. K ; Saryazdi, S ; Payab, E ; Sharif University of Technology
2013
Abstract
A manganese(III) complex, [Mn(phox)2(CH3OH) 2]ClO4 (phox = 2-(2′-hydroxyphenyl)oxazoline), was immobilized on silica-coated magnetic Fe3O4 nanoparticles through the amino propyl linkage using a grafting process in dichloromethane. The resulting Fe3O4@SiO2-NH2@Mn(III) nanoparticles are used as efficient and recyclable catalysts for selective oxidation of thiols to disulfides using urea-hydrogen peroxide as the oxidant. The nanocatalyst was recycled several times. Leaching and recycling experiments revealed that the nanocatalyst can be recovered, recycled, and reused more than five times, without the loss of catalytic activity and magnetic properties. The recycling of the nanocatalyst in six...
Synthesis and Study of Catalytic Activity of Iron (III)-bis(2-oxazolinyl) Methane complex by Urea Hydrogen Peroxide in Oxidation of Sulfides
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
Considerable effort has been directed in recent years towards the transition metal complex catalyzed oxidation of organic compounds. Herein the synthsis of the iron complex of bis(oxazoline) ligand as a novel catalyst is reported, and the catalytic activity of this complex in oxidation of sulfides is investigated. Bis(2-oxazolynil)methane as ligand is prepared by condensation of diethylmalonate with 2-aminoethanole in 1:2 molar ratio and finally corresponding complex is synthesized by the reaction between FeCl3.6H2O and Bis(2-Oxazolynil)methane in 1:1 molar ratio. The complex is characterized by using IR, UV-Vis, cyclic voltametery, conductometery and elemental analysis data. Moreover,...
Synthesis, Structure and Catalytic Application of Mn, Fe and Mo Complexes with Schiff base and Oxazoline ligands and Theoretical Mechanistic Studies on the Role of Heme and non-Heme Iron(IV)-Oxo Species in Hydroxylation and Epoxidation Reactions
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
The first part of this thesis describes the synthesis and characterization of several Mn, Fe and Mo complexes containing tridentate Schiff base and oxazoline ligands and their reactivities as catalysts in the oxidation of organic compounds like olefins and sulfides, as well. The crystal structures of newly prepared cis-dioxo-bis[2-(2′-hydroxyphenyl)-oxazolinato]molybdenum(VI), cis-[MoO2(phox)2] and (N-hydroxyphenyl-salicylidenamine)(acetylacetonato)ethanol iron(III), [FeIII(N-OPh-sal)(acac)EtOH] complexes have been described by X-ray crystallography. Due to the difficulties in the preparation of suitable single crystals of novel...
Experimental and Simulation Study of Formation Damage Due to Asphaltene Precipitation under CO2 Injection Condition in One of Iranian Carbonate Oil Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davoud (Supervisor)
Abstract
Asphaltenedeposition is a major problem during natural depletion and EOR processes due to formation damage issues. It is necessary to reveal asphaltene deposition mechanisms and its effective parameters to prepare an acceptable prevention strategy. Therefore, different natural depletion and EOR experiments must performed on core samples. In this research, Effect of CO2 injection on asphaltene deposition phenomena has been surveyed. Two carbonate core samples and one sandstone core sample was used in experiments. The oil used in these experiments was recombinedoilfrom one of Iranian offshore oilfield.In order to estimate permeability reduction during experiment, injection of oil and CO2 was...
Synthesis and Study of Catalytic Reactivity Oxo Vanadium (IV)& (V) Complexes with N,N'-Ethylenebis(Salicylimine)Ligand in Oxidation of Sulfides and Epioxidation of Olfins by Urea Hydrogen Peroxide (UHP) and Tert-Butyl Hydroperoxide (TBHP)
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
The selective oxidation of sulfides to sulfoxides is an important method in organic synthesis because sulfoxides are useful synthetic intermediates for the construction of various chemically and biologically significant molecules. To date, the most important method of preparation involves the oxidation of sulfides. Various oxidizing agents are used for this purpose. Oxovanadium(IV)(Salen) and oxovanadium(V)(Salen)Cl were synthesised and screened in the vanadium-catalysed oxidation of sulfides to solfuxides with urea hydrogen peroxide(UHP) as terminal oxidant. Both complexes showed good activity and selectivity trough the catalytic reaction.characterized by elemental analyses, IR, 1H and 13C...
Synthesis and Characterization of a novel Ruthenium(II) Complex With Bidentate O,N-donor OxazolineLigand and Study of Catalytic Oxidation of Sulfides and Alkanes
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
The 2-(2′-hydroxyphenyl)-oxazoline ligand (Hphox) is generated from 1:1 condensation of methyl salicylate with 2-aminoethanol. Novel [Ru(Hphox)2(H2O)2] (Hphox = 2-(2′-hydroxyphenyl)-oxazoline ) complex has been synthesized and characterized by physic-chemical methods. Oxidation of sulfides catalyzed by the mixed-ligand ruthenium(II) complex [Ru(Hphox)2(H2O)2]using urea-hydrogen peroxide (UHP) as oxidant was investigated under mild condition within 1 h. The results showed that mixed-ligand ruthenium(II) complex was effective catalyst in oxidation of sulfides in whichsulfoxideswere the only products. Using this catalytic system in the oxidation of alkanes, ketones were obtained as the main...
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
Inert gold become catalytically active when dispersed in the form of nanoparticles. Isolated gold nanoparticles have demonstrated high catalytic activity for both oxidation and reduction reactions. In order to obtain high catalytic activity, gold nanoparticles are generally dispersed on support materials, among which oxides are commonly used. However, a substantial decrease in activity and selectivity of the immobilized catalysts is frequently observed due to the heterogeneous nature of these support materials in reaction media. In the course of our study on the metal-based catalysis for synthesis of organic compounds, we herein report that rod-shaped Au nanoparticles in aqua solution...
Preparation of Heterogeneous Catalysts by Immobilization of Molybdenum and Manganese-shiff Base Complexes into the Nanopores of Zeolite and SBA-15
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
This thesisconsiders new fundamental approaches to yield heterogeneous catalysts in to three sections. The first section described the immobilization of the molybdenum-Schiff base complexes in pores of SBA-15 in two different methodologies depending on the actual structure of the complexes., (i) stepwise formation of the complex by initial covalent anchoring of one of the components and consecutive solid phase synthesis consisting of the condensation of the other components of the salen complex (iii) one-step complex immobilization by covalent binding through the ligand.Based on the first methodology, we report the preparation of ordered mesoporous silica SBA-15 containing a molybdenum...
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Reza (Supervisor)
Abstract
catalyzed oxidation of organic compounds such as olefins, sulfides, benzylics alcohols and phenolics. Cyanide-catalyzed aldimine coupling was employed to senthesize compounds with a-imineamine structural motifs : 2,3-di-(2-hydroxyphenyl)-1,2-dihydroquinoxaline, that way for synthesized NONO tetra-dentate Schiff-base ligands. With attention to solid geometry these ligands are possible to synthesize homo and hetronuclear mixed-ligand complexes. we are also synthesized homonuclear mixed-ligand Mn(III) and hetronuclear Mn(III)-Fe(III) with tetradentate Schiff-base ligand quinoxaline and acetyl acetone ligand. These complexes and ligands are characterized by FT-IR, 1H NMR, 13C NMR, UV and...
Synthesis and Characterization of Various Transition Metal Complexes and the Application in Oxidation, Heck, Suzuki, Sonogashira and Olefin Metathesis
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In nature, catalysis is of vital importance in a wide variety of biochemical processes catalyzed by metalloenzymes. The functions performed by the metalloenzymes and their significance have inspired a range of biomimetic studies, and intense efforts have been concentrated on the synthesis of low molecular weight complexes to model the spectroscopic features of such enzymes. Concomitantly, a challenging frontier in the field of biomimetic chemistry is the development of highly reactive model compounds that are able to effect rapid and selective substrate conversion. Some important catalytic transformations that have gained attention in recent years involve the carbon-carbon coupling, olefin...
Synthesis of Core-Shell Nanoparticles Supported Iron and Vanadium Schiff Base and Their Application as a Catalyst for Oxidation of Sulfides, Alcohols and Olefins
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this work, synthesized Fe3O4 magnetic nanoparticles andcoated with SiO2 to prepare magnetic core-shell nanoparticles. Then immobilized Schiff baseof iron and vanadium complexes on magnetic core-shell nanoparticles was prepared as a recoverable magnetic nano catalysts. These catalysts were named Fe3O4@SiO2@L1@Fe, Fe3O4@SiO2@L2@Fe and Fe3O4@SiO2@L3@V. Furthermore,olefines epoxidation, sulfides and alcohols oxidation were studied with using iron and vanadium magnetic nano catalysts. The supported catalysts were characterized by atomic absorption, FT-IR and UV–Vis spectra.The catalytic performance of the synthesized iron catalyst was tested for the epoxidation of cyclohexene, styrene and...
Synthesis of Metal-Organic Frameworks and Self-supported Coordination Polymers of Transition Metals with Catalytic Potential as Template for Supported Pd Nanoparticles and Preparation of Metal Oxide Nanoparticles for Olefin Epoxidation and C-C Coupling Reactions
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this research, synthesis of new heterogeneous catalysts has been studied. These catalysts were prepared in three different areas of the synthesis of coordination polymers and metal-organic frameworks, supported palladium nanoparticles on these polymers, and production of metal oxide nanoparticles. At first, metal organic frameworks of cobalt and manganese transition metals were synthesized through hydrothermal method. In order to prepare these frameworks, 1,4-benzenedicarboxylic acid (terephthalic acid) and 2-amino-1,4-benzenedicarboxylic acid ligands were utilized as spacer ligands. X-ray analysis indicated that the structure of polymers is composed of secondary building units (SBUs) of...
Heterogenization of Ionic Complexes of Mo(VI) with Sulfonated Schiff Base Ligands on the Polysiloxane as Support for Catalytic Epoxidation of Olefins
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this project a new molybdenum (VI) complex with tetradentate Schiff base ligand which was soluble in water was synthesized and characterized. In the first step of ligand synthesis, the reaction was performed between salicylaldehyde and aniline, and then used concentrated sulfuric acid for sulfonation. In the next step 5- sulfosalicylaldehyde sodium salt was formed by removing of aniline with heating and using sodium carbonate. In the presence of ethylendiamine and bis (acetylacetonato) dioxomolybdenum(VI) the final product, cis-dioxo sodium (N,N-bis (5-sulfonatosalicyldene)1,2-diaminoethane) molybdenum (VI) complex was synthesized. The complex was characterized by (CHN) elemental...
Synthesis and Characterization of Cis-dioxomolybdenum(VI) Complex with an ONOtype Tridentate Schiff base Ligand and its Application as a Catalyst for Epoxidation of Olefinsin Water
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
New dioxomolybdenum(VI) complex has been synthesized by reacting N-hydroxyphenyl-[5-(triphenylphosphonium)methyl]salicylideneamine chloride (PPh3-H2sap) as a water soluble ligand and [MoO2(acac)2] in ethanolic solution. The water soluble ligand (PPh3-H2sap) was prepared by reaction of 2-aminophenol with (3-formyl-4-hydroxybenzyl)triphenylphosphonium chloride as a water solublesalicylaldehyde derivative. The resulting complex with the formula [MoO2(PPh3-H2sap)(EtOH)] which contains an ethanol molecule in sixth site of coordination, was characterized by elemental analyses, 1H NMR,31P NMR, IR and UV-Vis spectroscopic studies. This complex was tested as a catalyst for the homogeneous...