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Characterization of Micromixing and Determination of Mass-Transfer Coefficient in a new Double-Spinning-Disk Contactor
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
High mixing efficiency and high liquid-liquid mass transfer rate are two key features of spinning disk contactors. This work presents the experimental investigation of mixing and liquid-liquid mass transfer characteristics in a new double coaxial spinning disks contactor. The micromixing efficiency was investigated using a standard system of competitive parallel reaction known as iodide/iodate test reaction. The influences of various operating conditions such as the rotational speed of the disks, the direction of rotation, the feed radial location, the feed distribution pattern, the distance between the disks, and the feed flow rate on the mixing quality were examined carefully. The obtained...
Oxidative Desulfurization of Gas Condensate
, M.Sc. Thesis Sharif University of Technology ; Seifkordi, Ali Akbar (Supervisor) ; Bazmi, Mansour (Co-Advisor) ; Ghaedian, Maryam (Co-Advisor)
Abstract
Due to increasing environmental concern, special interest has been paid to reduction of organosulfur compounds in transportaion fuels. The sulfur- containing compounds are converted into sulfur oxide, i.e, SOx , during combustion, which is a major source of acid rain and air pollution.Gas condensate is a mixture consisting primarily of pentanes and heavier hydrocarbons which is recovered as a liquid from natural gas. It is a proper hydrocarbon source for producing gasoline, kerosene and gas oil in refineries. In this reseach a gas condensate was used as feedstock for studing oxidative desulfurization (ODS). The influence of various parameters of desulforization including the reaction...
Kinetic Study of Carbonylation of Methanol Using Homogenous Iridium Catalyst
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Mhammad Rezaee, Alireza (Supervisor)
Abstract
Homogenous carbonylation of methanol is a major way to acetic acid. In this study central composite design (CCD) at five level (-1.63, -1, 0, +1, +1.63) combined with response surface methodology (RSM) have been applied to optimize carbonylation of methanol using ruthenium promoted iridium catalyst in homogenous phase. The effect of seven process variables including; temperature, pressure, iridium, ruthenium, methyl iodide, methyl acetate and water concentrations as well as, their interactions were modeled. The determined R2 values greater than 0.9 for the rate, methane, carbon dioxide and hydrogen formation data, confirmed quadratic equation properly fitted obtained experimental data. The...
Preparation a Polymeric Membrane for Dehydration of Acetic Acid
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Bastani, Dariush (Supervisor)
Abstract
The separation ofacetic acids in binary water solutions hasbeenstudied using a reverse osmosis (RO) membrane. Thin film composite polyamide membrane is used in this study.Thin-film composite (TFC) membrane was prepared through the interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on the polysulphone support membrane.The solute permeation was carried out under applied pressure of 5 bar at 25°C. In this work the effect of various synthesis conditions on the membrane performance was investigated. Parametric studies were conducted by varyingconcentration of reactants, reaction time, curing time and curing temperature. By suitable combination of these...
Synthesis and characterization of TiO2-graphene nanocomposites modified with noble metals as a photocatalyst for degradation of pollutants
, Article Applied Catalysis A: General ; Vol. 462–463 , July , 2013 , Pages 82–90 ; Esfandiarb, A. (Ali) ; Rahman Setayesha, S. (Shahrbano) ; Habibi-Yangjehc, A. (Aziz) ; Iraji zadb, A. (Azam) ; Gholamia, M .R. (Mohammad Reza) ; Sharif University of Technology
Abstract
TiO2–graphene (TiO2–GR) nanocomposites were synthesized using photocatalytic reduction method. TiO2–GR nanocomposites were thereafter doped with noble metals (Pt and Pd) by chemical reduction of the corresponding cations. The samples were characterized by different techniques. The addition of GR to TiO2 decreases the crystalline size of TiO2 due to the homogeneous dispersion of the TiO2 nanoparticles on GR sheets and prevention of coagulation of TiO2 nanoparticles during synthesis process. In addition, the surface area of TiO2 was increased by addition of GR and deposition of noble metals which helps to prevent agglomeration of graphene sheets and TiO2 nanoparticles. Red shifts to the higher...
Grafting the sol-gel based sorbents by diazonium salts: A novel approach toward unbreakable capillary microextraction
, Article Journal of Chromatography A ; Volume 1318 , November , 2013 , Pages 58-64 ; 00219673 (ISSN) ; Bayat, P ; Piri Moghadam, H ; Sharif University of Technology
2013
Abstract
The present work deals with a novel approach for grafting a sol-gel based sorbent, using diazonium salts for preparation of an unbreakable capillary microextraction (CME) device in on-line combination with high performance liquid chromatography (HPLC). The use of diazonium salts modifier allowed all types of metallic and non-metallic substrates to be used without any limitation. Substrates including copper, brass, stainless steel and polytetrafluoroethylene (PTFE) were chosen to be functionalized by chemical or electrochemical reduction of 4-amino phenyl acetic acid. Then, 3-(trimethoxysilyl)propylamine (3TMSPA) was selected as the precursor and the only reagent for preparation of the...
Efficient one-pot four-component synthesis and X-ray crystallographic structure of 2-pyridone derivatives
, Article Journal of Heterocyclic Chemistry ; Volume 50, Issue 6 , 2013 , Pages 1272-1280 ; 0022152X (ISSN) ; Hashemi, M. M ; Khezri, S. H ; Rominger, F ; Ghabraie, E ; Oeser, T ; Sharif University of Technology
2013
Abstract
A series of 3-cyano-2-pyridone derivatives were synthesized by one-pot four-component condensation reaction involving a benzaldehyde derivative, alkyl cyanoacetate, acyclic or cyclic ketones, and ammonium acetate in reflux condition. The X-ray structure of the products 5a and 5d confirm symmetric dimers via hydrogen bonding interactions between individual pyridine molecules showing, in addition, also π-π stacking interactions
The stereoselective synthesis of tetrahydrothiopyrano[2,3-b]indole skeletons via tandem reaction of indoline-2-thiones to Baylis-Hillman adduct acetates
, Article Tetrahedron ; Volume 69, Issue 38 , September , 2013 , Pages 8169-8173 ; 00404020 (ISSN) ; Foroushani, B. K ; Sobhani, M ; Masoud, N ; Khodabakhshi, M. R ; Weng, N. S ; Sharif University of Technology
2013
Abstract
Indoline-2-thiones (5) were applied as 1,3-dinucleophiles in a tandem reaction with Baylis-Hillman adduct acetates (4) to give novel tetrahydrothiopyrano[2,3-b]indole skeletons (6). The effect of different solvents, bases, and catalysts on the yields and stereochemical outcome was studied in detail. The results indicated that acetonitrile as solvent and K 2CO3 as base, under reflux conditions, were the optimum conditions. Products 6a-6l were obtained in high diastereoselectivity and yield (up to 94%)
Synthesis and characterization of TiO2-graphene nanocomposites modified with noble metals as a photocatalyst for degradation of pollutants
, Article Applied Catalysis A: General ; Volume 462-463 , 2013 , Pages 82-90 ; 0926860X (ISSN) ; Esfandiar, A ; Rahman Setayesh, S ; Habibi Yangjeh, A ; Iraji Zad, A ; Gholami, M. R ; Sharif University of Technology
2013
Abstract
TiO2-graphene (TiO2-GR) nanocomposites were synthesized using photocatalytic reduction method. TiO2-GR nanocomposites were thereafter doped with noble metals (Pt and Pd) by chemical reduction of the corresponding cations. The samples were characterized by different techniques. The addition of GR to TiO2 decreases the crystalline size of TiO2 due to the homogeneous dispersion of the TiO2 nanoparticles on GR sheets and prevention of coagulation of TiO2 nanoparticles during synthesis process. In addition, the surface area of TiO2 was increased by addition of GR and deposition of noble metals which helps to prevent agglomeration of graphene sheets and TiO 2 nanoparticles. Red shifts to the...
Study of droplet behaviour along a pulsed liquid-liquid extraction column in the presence of nanoparticles
, Article Canadian Journal of Chemical Engineering ; Volume 91, Issue 3 , 2013 , Pages 506-515 ; 00084034 (ISSN) ; Bahmanyar, A ; Molavi, H ; Bastani, D ; Mozdianfard, M. R ; Bahmanyar, H ; Sharif University of Technology
2013
Abstract
In this article, droplet size and its distribution along a pulsed liquid-liquid extraction column, is studied where SiO2 nanoparticles with concentrations of 0.01, 0.05 and 0.1vol.% and different hydrophobicities are applied to the dispersed phase. Using ultrasonication, nanoparticles were dispersed in kerosene as the base fluid. Nanofluids' stability was ensured using a UV-vis spectrophotometer. Some 22,000 droplets were measured by photographic technique and results were compared with systems containing no-nanoparticles (Water-Acetic acid-Kerosene). Addition of nanoparticles changed the droplet shape from ellipsoidal to spherical. Also, there was a marked influence on droplet breakage and...
Bimodal electricity generation and aromatic compounds removal from purified terephthalic acid plant wastewater in a microbial fuel cell
, Article Biotechnology Letters ; Volume 35, Issue 2 , 2013 , Pages 197-203 ; 01415492 (ISSN) ; Kariminia, H. R ; Savizi, I. S. P ; Sharif University of Technology
2013
Abstract
Wastewater of purified terephthalic acid (PTA) from a petrochemical plant was examined in a membrane-less single chamber microbial fuel cell for the first time. Time course of voltage during the cell operation cycle had two steady phases, which refers to the fact that metabolism of microorganisms was shifted from highly to less biodegradable carbon sources. The produced power density was 31.8 mW m-2 (normalized per cathode area) and the calculated coulombic efficiency was 2.05 % for a COD removal of 74 % during 21 days. The total removal rate of different pollutants in the PTA wastewater was observed in the following order: (acetic acid) > (benzoic acid) > (phthalic acid) > (terephthalic...
A metabonomics study on crohn's disease using nuclear magnetic resonance spectroscopy
, Article HealthMED ; Volume 6, Issue 11 , July , 2012 , Pages 3577-3583 ; 18402291 (ISSN) ; Kyani, A ; Nejad, M. R ; Rezaye Tavirani, M ; Naderi, N ; Zali, M. R ; Tafazzoli, M ; Oskouie, A. A ; Sharif University of Technology
2012
Abstract
Objective: Crohn's disease (CD) is one the important illnesses can affect any part of the gastrointestinal tract. CD is not easily diagnosed using the clinical tests. Thus, the discovery of proper methods would be a major step towards CD diagnosis. The aim of this study was to seek the metabolic biomarkers causes of CD compare to control group. Materials and Methods: In present study, we employed metabolic profiling using proton nuclear magnetic resonance spectroscopy (1HNMR) to find metabolites in serum which are helpful for the diagnosis of CD. Classification of CD and healthy subject was done using classification and regression trees (CART). The metabolites that caused changes in people...
Minimizing CO2 formation in Ir-catalyzed methanol carbonylation process
, Article 20th International Congress of Chemical and Process Engineering, CHISA 2012, Prague, 25 August 2012 through 29 August 2012 ; 2012 , Pages 1179-1188 ; 18777058 (ISSN) ; Hosseinpour, V ; Sharif University of Technology
2012
Abstract
Acetic acid is one of the most important petrochemical products. Carbonylation of methanol in homogenous phase is one of the major routes for production of acetic acid. Amongst group VIII metal catalysts used in this process iridium has displayed the best capabilities. To investigate effect of operating parameters like: temperature, pressure, methyl iodide, methyl acetate, iridium, ruthenium, and water concentrations on the carbon dioxide formation, experimental design for this system based upon central composite design (CCD) was utilized. Statistical carbon dioxide formation equation developed by this method contained individual, interactions and curvature effects of parameters on the...
Effect of hydrogen bonds on pK a values: Importance of networking
, Article Journal of the American Chemical Society ; Volume 134, Issue 25 , 2012 , Pages 10646-10650 ; 00027863 (ISSN) ; Abedin, A ; Fattahi, A ; Kass, S. R ; Sharif University of Technology
2012
Abstract
The pK a of an acyclic aliphatic heptaol ((HOCH 2CH 2CH(OH)CH 2) 3COH) was measured in DMSO, and its gas-phase acidity is reported as well. This tertiary alcohol was found to be 10 21 times more acidic than tert-butyl alcohol in DMSO and an order of magnitude more acidic than acetic acid (i.e., pK a = 11.4 vs 12.3). This can be attributed to a 21.9 kcal mol -1 stabilization of the charged oxygen center in the conjugate base by three hydrogen bonds and another 6.3 kcal mol -1 stabilization resulting from an additional three hydrogen bonds between the uncharged primary and secondary hydroxyl groups. Charge delocalization by both the first and second solvation shells may be used to facilitate...
An experimental design approach to determine effects of the operating parameters on the rate of Ru promoted Ir carbonylation of methanol
, Article World Academy of Science, Engineering and Technology ; Volume 73 , March , 2011 , Pages 598-603 ; 2010376X (ISSN) ; Kazemini, M ; Mohammadrezaee, A ; Sharif University of Technology
Abstract
carbonylation of methanol in homogenous phase is one of the major routesfor production of acetic acid. Amongst group VIII metal catalysts used in this process iridium has displayed the best capabilities. To investigate effect of operating parameters like: temperature, pressure, methyl iodide, methyl acetate, iridium, ruthenium, and water concentrations on the reaction rate, experimental design for this system based upon central composite design (CCD) was utilized. Statistical rate equation developed by this method contained individual, interactions and curvature effects of parameters on the reaction rate. The model with p-value less than 0.0001 and R 2 values greater than 0.9; confirmeda...
The influence of nanoparticles on hydrodynamic characteristics and mass transfer performance in a pulsed liquid-liquid extraction column
, Article Chemical Engineering and Processing: Process Intensification ; Volume 50, Issue 11-12 , 2011 , Pages 1198-1206 ; 02552701 (ISSN) ; Khoobi, N ; Mozdianfard, M. R ; Bahmanyar, H ; Sharif University of Technology
Abstract
With respect to the influence of nanoparticles on mass transfer characteristics, limited number of studies available in the literature, deal primarily with gas-liquid systems. In this work, mass transfer performance and hydrodynamic characteristics including static and dynamic dispersed phase hold-ups of nanofluids have been investigated for pulsed liquid-liquid extraction column (PLLEC). The nanofluids used were prepared by dispersing SiO2 nanoparticles of 0.01, 0.05 and 0.1 volume percent with two different hydrophobicities in kerosene as base fluid using ultrasonication. UV-vis spectrophotometer was also used for evaluation of the nanofluids stability. The results were compared with...
A study of the water-gas shift reaction in Ru-promoted Ir-catalysed methanol carbonylation utilising experimental design methodology
, Article Chemical Engineering Science ; Volume 66, Issue 20 , October , 2011 , Pages 4798-4806 ; 00092509 (ISSN) ; Kazemeini, M ; Mohammadrezaee, A ; Sharif University of Technology
2011
Abstract
The water-gas shift reaction occurs competitively to the main reaction of the Ir-catalysed methanol carbonylation process. To study the effect of seven factors including temperature, pressure, iridium, ruthenium, methyl iodide, methyl acetate and water concentrations on the formation of hydrogen and carbon dioxide as a result of the water-gas shift reaction and other side reactions in the carbonylation of methanol to acetic acid, the experimental design method combined with response surface methodology (RSM) was utilised. Central composite design at five levels (with α=1.63) was used to design experiments. A quadratic model that included the main and interaction effects of variables for H 2...
Electrocatalytic determination of sumatriptan on the surface of carbon-paste electrode modified with a composite of cobalt/Schiff-base complex and carbon nanotube
, Article Bioelectrochemistry ; Volume 81, Issue 2 , 2011 , Pages 81-85 ; 15675394 (ISSN) ; Pakdel, Z ; Bezaatpour, A ; Shahrokhian, S ; Sharif University of Technology
2011
Abstract
The electrochemical oxidation of sumatriptan on the surface of carbon paste electrode modified with multi-walled carbon nanotube and cobalt methyl-salophen complex is studied by using cyclic voltammetry and polarization studies. The results indicate that the drug is irreversibly oxidized in a one electron oxidation mechanism. It was found that the peak potential shifted negatively with increasing pH, confirms that H + participate in the oxidation process. The electrode is shown to be very effective for the detection of sumatriptan in the presence of other biological reductant compounds. The prepared modified electrode exhibits a very good resolution between the voltammetric peaks of...
Column and batch study of haloacetic acids adsorption onto granular activated carbon
, Article Research Journal of Chemistry and Environment ; Volume 15, Issue 2 , Jun , 2011 , Pages 866-872 ; 09720626 (ISSN) ; Mousavi, S. M ; Soltanieh, M ; Seif, K. A. K ; Sharif University of Technology
2011
Abstract
The granular activated carbon (GAC) was used as an adsorbent for its ability to remove haloacetic acids (HAAs) from drinking water by batch and column experiments. Various thermodynamic parameters, such as ΔG°, ΔH° and ΔS° have been calculated. The thermodynamics of HAAs onto GAC system indicates spontaneous and exothermic nature of the process. The ability of GAC to adsorb HAAs in a fixed bed column was investigated as well. The effect of operating parameters such as flow rate and inlet HAAs concentration on the sorption characteristics of GAC was investigated. The total adsorbed quantities, equilibrium uptakes and total removal percents of HAAs related to the effluent volumes were...
Optimisation of Ru-promoted Ir-catalysed methanol carbonylation utilising response surface methodology
, Article Applied Catalysis A: General ; Volume 394, Issue 1-2 , February , 2011 , Pages 166-175 ; 0926860X (ISSN) ; Kazemeini, M ; Mohammadrezaee, A ; Sharif University of Technology
2011
Abstract
In this study, central composite design (CCD) at five levels (-1.63, -1, 0, +1, +1.63) combined with response surface methodology (RSM) have been applied to optimise methanol carbonylation using a ruthenium-promoted iridium catalyst in a homogenous phase. The effect of seven process variables, including temperature, pressure, iridium, ruthenium, methyl iodide, methyl acetate and water concentrations, as well as their binary interactions, were modelled. The determined R 2 values greater than 0.9 for the rate and methane formation data confirmed that the quadratic equation properly fitted the obtained experimental data. The optimum conditions for maximum rate and minimum methane formation were...