Sharif Digital Repository

Solid fuel ignition transient in dump combustor geometry is numerically studied. The objective of this work is to gain insight into the ignition of the fuel and its controlling parameters in back-step turbulent flow. The system of governing equations is solved with a finite volume approach using a structured grid in which the AUSM+ scheme is used to calculate the gas phase convective fluxes. The Spalart-Allmaras turbulence model is used in these simulations. First, the auto-ignition of solid fuel subject to an inlet oxidizer flow at elevated temperatures is considered and distinct intervals in ignition delay time are studied. We have demonstrated that for inlet oxidizer streams with high... 

Dithiocarbamates are a group of compounds that nowadays have been used extensively in pharmaceutical agents, organicsynthesis and as fungicides in agriculture.We haveshown, an efficient. regiospecific method for the synthesis of cyclic dithiocarbamates by one-pot three-component cascade reaction of an amine, CS2 and α,β-unsaturated aldehyde via Michael addition/hemiamination reaction in watre under a mild and green procedure with excellent yields and complete regioselectivity  

In this research, a new group of N2O2–azacrown macrocyclic ligands with different macroring size from 15 to 18 was synthesized using one-pot facile and high yield reaction. The products were characterized applying FT-IR, 1H and 13C NMR spectroscopies as well as elemental analysis. The single crystal structure of 18-membered macrocyclic ligand was also determined by x-ray crystallography. The crystallographic data showed such strong inter-molecular hydrogen bonding which excluded their nitrogen-donor groups, and initial investigation with UV-Vis spectroscopy shows no intraction with [60]fullerene, despite of presence of these interacrtions in their parent macrocycles. The result of Job’s... 

In the first chapter of the thesis the synthesis of indolylsulfanyl acetamide derivatives using thio-oxindoles has been reported. The properties of this reaction are, one-pot, without using catalysts, acetonitrile solvent and the raw material is available. This reaction has high yield and seperation products is done using column chromatography. Indole derivatives has various medicinal and biological properties and synthetic products in this project has indole ring, aldehyde and amide functional groups. In the second chapter of the thesis, a new magnetic nanocatalyst has been designed. The magnetic nanoparticles were coated with triazole ligand and then palladium (II) ion was loaded onto the... 

In this thesis, heterogenous catalysts based on magnetic nanoparticles were synthesized. In these catalysts, magnetic nanoparticles were coated with defferent fuctional groups to produce a catalyst with magnetic properties which is easily separated from the reaction medium. The structure of synthesized catalyst was characterized using techniques such as transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and CHNS elemental analysis. Easy preparation, low cost, biodegradability and high thermal stability are advantages of these catalysts. At the end, the catalytic properties of resulted catalysts were investigated in many... 

Bioorthogonal chemistry defines any reaction, inside or outside the living systems, without interfering with native chemical processes and 3dimensional structure of proteins. In these types of reactions water is the sole solvent; a neutral pH is required; the temperature must be up to 40 oC. The kinetics of reactions must be on the hour scale and the nontoxic reagents with low concentration must be used. One of the simplest methods of visualizing protein molecule is covalent attachment of fluorescein to protein. In this work several fluorescent compounds were synthesized. These novel compounds include acylchloride fluorescein, N-hydroxysuccinimide fluorescein, thiophenol fluorescein, and... 

One of the most challengeable topic in the field of green chemistry is the synthesis of organic structure in water. In this project immobilized glucose on Fe3O4 was prepared as a nano heterogeneous dispersive catalyst in water. The catalyst was fully characterized by FT-IR, TGA, CHN, SEM, EDX and atomic absorption spectroscopy. The synthesized catalyst was used in the synthesis of different derivatives of 1,2,3-triazole via one-pot three component reaction of alkynes, alkyl halides, sodium azides; And to the best of our knowledge this novel catalyst coin sides to the principles of green chemistry. This nano catalyst can be recycled and reused for several runs without significant loss of its... 

Development of strategically important processes which are environmentally benign with simple methodology and work-up by low toxic material is currently reciving considerable attention.In recent years, dithiocarbamates (DTCs) and their synthesis with a green procedure have received many attention because of their undeniable applications.These synthetic compounds play important roles either in academia and industry. Here a simple, efficient and regiospecific method for synthesis of dithiocarbamates is described by one-pot three-component reaction of an amine, CS2 and alkyl vinyl ether via Markovnikov addition reaction in poly ethylene glycol (PEG) under a mild and green procedure with... 

New N4O6 molecular tweezers were synthesized from N2O2 benzo- and naphthodiazacrown macrocycles bearing benzylic dialdehydes as a flexible and semi-flexible spacer in a short time and at room temperature. The products were characterized by IR, 1H and 13C NMR spectroscopy as well as elemental microanalysis. The interactions of some of these tweezers with C60, Cu(II), Co(II), Ni(II), Zn(II), Hg(II) and Mn(II) were investigated by employing UV-Vis and fluorescence spectroscopy. Efficient fluorescence responses for 2NM3BD were observed in the presence of C60, Cu(II), Mn(II), Hg(II) and Zn(II). Meanwhile, the calculation of the association constants (K¬BH) employing Benesi-Hildebrand equation in... 

Quorum Sensing is a cell-to-cell communication pr°Cess depending on cell concentration. Communication among bacterial cells °Ccurs through small molecular signals called autoinducers. The consequences of quorum sensing include the activation of pathogenic properties and activation of the gene for biofilm formation. Biofilms are aggregations of bacteria that adhere to surfaces through extracellular polymeric substances. Bacteria in the biofilm phase are much more resistant to antimicrobial agents than their free-swimming counterparts (i.e. the bacteria in planktonic form). In this study, first a series of coumarin derivatives were synthesized; but due to low solubility of the synthesized... 

This thesis contains four chapters. In first chapter the role of water in organic reactions as a ecofriendly solvent, computational chemistry and dynamic nuclear magnetic resonance were studied. In the second chapter synthesis of new 4-hydroxy pyrrole derivatives in water were reported. For the synthesis of these compounds arylglyoxal derivatives, 1,3-dicarbonyl compounds and ammonium acetate were used. The reaction conditions are very mild. The third chapter contains the synthesis of new (4 or 5)-Aryl-2-aryloeil-(1H)-imidazole compounds in aqueous media. We also investigated the tauto-isomerisation of isomeric imidazoles during this reaction using DNMR technique. In forth chapter a... 

Two new copper(II) complexes, [CuL2] and [Cu(phox)2], were synthesized by reaction of 1-((4-bromophenylimino)methyl)naphthalen-2-ol, HL, and 2-(2′-hydroxyphenyl)-2-oxazoline, Hphox, as ligands and copper(II) acetate mono-hydrate with the ratio 2:1 (ligand:metal), respectively. For characterization and structure determination of synthesized complexes, different techniques were performed such as FT-IR, elemental analyses (CHN), and X-ray crystallography. The geometry around Cu atom is almost square planar in both complexes. The catalytic activity of the complexes was evaluated in azide–alkyne cycloaddition reaction in water without need of any additional agent. The reaction conditions for the... 

The current thesis deals with designing of functionalized nanoporous catalysts modified with organic groups and ionic liquids and their applications for some challenging organic reactions such as synthesis of adipic acid and fatty acid esterifications. In this condition the catalysts show enhanced activity since the hydrophobicity of the surface can tune by applying organic groups. In this regard, oxidation of cyclohexene was performed using hydrogen peroxide as oxidant in the present of tungstate based task–specific ionic liquids and silica–functionalized ammonium tungstate as green catalysts. The results indicate that adipic acid achieves in high yield with excellent selectivity.... 

A novel magnetic heterogeneous copper catalyst was synthesized by immobilization ofcopper ion onto the triazole functionalized Fe3O4. The catalyst was fully characterized by FTIR, TGA, CHN, SEM, TEM, EDX and atomic adsorption spectroscopy. The resulting catalystwas used in the synthesis of 1,2,3-triazoles via one-pot three component reaction of alkynes,alkyl halides, sodium azides under green condition. The catalyst was reused for ten times andno significant loss of activity was observed. Supported gold (III) on poly(ionic liquid) coated on magnetic nanoparticles produced a highly active, stablerecoverable and high loading for the synthesis of propargylamines (A3 coupling reaction) under... 

Antioxidants are compounds with anti-cancer, anti-bacterial, anti-viral, anti-aging and anti-allergic properties. In the present study, a quantum mechanical approach has been used to shed light on the presence effect of glycoside group on the antioxidant ability of chrysin as one of the most important consumable flavonoids and two glycoside derivatives, chrysin-6-C-fucopyranoside and chrysin-3-malonyl-6-C-fucopyranoside which has electron-withdrawing group (EWG) in its C3 of glycoside group. Density functional theory (DFT) using B3LYP and UB3LYP functional and split-valance 6-311++G ** basis set were used to optimize chrysin, its different derivatives, and their radicals. Analysis of... 

In the first section of the present thesis, a number of novel heterocycles were prepared; they include spirodihydropyridine, spiroindoline-2-thion, and pyrrolopyrimidines. The major advantages of the current investigation encompass high yields, short reaction times, mild reaction conditions and feasibility and low-cost materials. In the second section of this thesis, heterogeneous catalysts based on magnetic nanoparticles coated with organosilanes were synthesized. These catalysts were synthesized by hydrolysis of tetraethyl organosilanes and other organosilicons such as 3-aminopropyl triethoxy silane. The synthesized scaffolds were used to stabilize precious metals as Pd and Cu. The... 

Transparent conductive electrode (TCE) is one of the indispensable constituent of optoelectronic devices, which heretofore various materials such as ITO, graphene, CNT, metal nanowire and nanofiber network have been used to produce them. It should also be assumed that the use of low-cost materials, which has cost-effective production method, is essential for the construction of transparent electrodes. Copper nanofiber network film which is obtained from electrospinning process is a promising candidate among these materials because it has superiorities, such as low sheet resistance, proper flexibility and abundance in ground resources, scalable and cost-effective fabrication method. There are... 

In first part Mesoporous silica (SBA-15) was synthesized by template synthesis method and the surface of SBA-15 was functionalized with 3-glycidoxypropyltrimethoxysilane and 5-Phenyl-1H-tetrazole. Palladium nanoparticles were immobilized on the aforementioned mesoporous support. Characterization of catalyst regarding to its structure, morphology and other parameters was investigated by physiochemical analysis such as XRD, SEM, TEM, and TGA. This heterogeneous catalyst has high capability in reduction of nitrobenzenes and selective oxidation of primary alcohols which respectively gain aminoarenes and benzaldehydes in high yields. Reduction and oxidation reactions are done in water as a green... 

Titanomagnetites are resources of iron and titanium. high level of titanium in titanomagnetites makes using them in iron making processes very difficult. In this work an attempt was made to produce an iron bearing and a titanium bearing product using solid state reduction of Fanouj mine titanomagnetite concentrate. For this purpose, the concentrate was reduced using coal and then was subjected to magnetic separation. In this work, effect of temperature, time, added coal amount, and additive amount on reduction was studied. The result showed that the optimum conditions are 1325 celsius degree, 2.5 hours, 25 percent added coal and 2 percent additive. In optimum conditions a magnetic product... 

The existing thesis investigates the removal efficiency of ammonia from wastewater using natural zeolite, and the effects of various parameters on the removal efficiency. The importance of this research is due of the fact that ammonia is among the primary contaminants of wastewater. The common method of removing ammonia is biological processes that have a number of drawbacks. The ion exchange method could be a suitable alternative to the former method. Ammonia removal from wastewater was investigated through both batch and continuous experiments. In these experiments the initial ammonia concentration in the wastewater was chosen to be 1000 mg/L, 100 mg/L. The optimum ammonia removal was...