Loading...
Search for: reaction-kinetics
0.007 seconds
Total 160 records

    Kinetic study of catalytic hydrolysis reaction of methyl acetate to acetic acid and methanol

    , Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 30, Issue 5 , 2006 , Pages 595-606 ; 03601307 (ISSN) Ehteshami, M ; Rahimi, N ; Eftekhari, A. A ; Nasr, M. J ; Sharif University of Technology
    2006
    Abstract
    The reaction kinetics and chemical equilibrium of the reversible catalytic hydrolysis reaction of a methyl acetate to acetic acid and methanol using a strongly acidic ion exchange resin catalyst named Amberlyst 15 were studied. To investigate the different behavior of Amberlyst 15 in the adsorption of reactants and product species, the equilibrium behavior of binary non-reactive liquid mixtures, consisting of one reactant and one product were studied experimentally. The Langmuir model was used to describe the equilibrium condition, quantitatively. Then the employed model was compared with the more complicated thermodynamic models to describe the equilibrium between the catalytic polymer... 

    Synthesis of Modified Porous Nanostructures and Investigation of Oxidation Reaction Kinetics

    , M.Sc. Thesis Sharif University of Technology Gholizadeh, Sepideh (Author) ; Gholami, Mohammad Reza (Supervisor)
    Abstract
    In this work ،we used the hydrothermal method for prepared the Bivo4 nano particles. For the best photocatality property these nano particles stabilized on the different basis. This catalysis characterized by UV-vis, XRD, BET, FTIR and SEM. The size of zeolites catalyst were 22 nm and size of Bivo4 were 54 nm and the SEM showed that the BivO4 were sphere. By addition of BiVO4 nano particles to the surface of zeolite, the surface area was increase, but addition of BiVO4 nano particles to surface, the average of holes size decreased and distribution of holes will be monotonous and the surface area increased. In the continue for investigation of photo catalyst activity of nano particle, we used... 

    Direct dyes removal using modified magnetic ferrite nanoparticle

    , Article Journal of Environmental Health Science and Engineering ; Vol. 12, Issue. 1 , 28 May , 2014 ; ISSN: 2052336X Mahmoodi, N. M ; Abdi, J ; Bastani, D ; Sharif University of Technology
    Abstract
    The magnetic adsorbent nanoparticle was modified using cationic surface active agent. Zinc ferrite nanoparticle and cetyl trimethylammonium bromide were used as an adsorbent and a surface active agent, respectively. Dye removal ability of the surface modified nanoparticle as an adsorbent was investigated. Direct Green 6(DG6), Direct Red 31 (DR31) and Direct Red 23 (DR23) were used. The characteristics of the adsorbent were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of adsorbent dosage, initial dye concentration and salt was evaluated. In ternary system, dye removal of the adsorbent at 90, 120, 150 and 200 mg/L... 

    Optimization of biomass and biokinetic constant in Mazut biodegradation by indigenous bacteria BBRC10061

    , Article Journal of Environmental Health Science and Engineering ; Vol. 12, issue. 1 , June , 2014 Khorasani, A. C ; Mashreghi, M ; Yaghmaei, S ; Sharif University of Technology
    Abstract
    Optimization based on appropriate parameters can be applied to improve a process. Mazut degradation as a critical issue in environment requires optimization to be efficiently done. To provide biodegradation conditions, experiments were designed on the least interactions among levels of parameters consisting of pH, Tween 80, glucose, phosphorous source, nitrogen source, and time. Kinetic constants and biomass were calculated based on 16 assays, designed using Taguchi method, which constructed various mazut biodegradation conditions. Kinetics of mazut degradation by newly isolated bacteria Enterobacter cloacae closely followed second order kinetic model. Results of the 16 experiments showed... 

    Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: Improving and kinetic investigation

    , Article Iranian Journal of Environmental Health Science and Engineering ; Volume 10, Issue 2 , 2013 ; 17351979 (ISSN) Khorasani, A. C ; Mashreghi, M ; Yaghmaei, S ; Sharif University of Technology
    2013
    Abstract
    Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration... 

    Conversion of a weak organic acid to a super acid in the gas phase

    , Article Journal of Physical Organic Chemistry ; Volume 21, Issue 2 , 2008 , Pages 112-118 ; 08943230 (ISSN) Fattahi, A ; Tavasoli, E ; Sharif University of Technology
    2008
    Abstract
    The effects of selected metal ions on the gas-phase acidity of weak organic acids have been explored using the DFT and Moller-Plesset Perturbation Theory (MP2) calculations. The three organic acids selected for this study were acetic acid (aliphatic), benzoic acid (aromatic), and glycine (amino acid). The acidities of these compounds are compared with the acidity of their Li +-, Na+-, and K+ -complexed species. The results indicate that upon complexation with Li+, Na+, and K+ at 298K, the gas-phase acidity of acetic acid, for example, varies from 345.3 to 218.8, 230.2, and 240.1 kcal/mol, respectively (i.e., its dissociation becomes much less endothermic). These values indicate that a weak... 

    Evaluation of zeolites in production of tetrahydrofuran from 1,4-butanediol: Performance tests and kinetic investigations

    , Article Industrial and Engineering Chemistry Research ; Volume 46, Issue 3 , 2007 , Pages 726-733 ; 08885885 (ISSN) Aghaziarati, M ; Kazemeini, M ; Soltanieh, M ; Sahebdelfar, S ; Sharif University of Technology
    2007
    Abstract
    The liquid-phase dehydration of 1,4-butanediol to tetrahydrofuran was investigated over various materials including synthetic zeolites, namely, ZSM-5, Y, Mordenite, Ferrierite, and Beta as well as silica and alumina. The key characters investigated were the Si/Al ratio and cation exchange. The results showed that the ZSM-5 zeolite exchanged with NH4+ exhibited the highest activity in dehydration of 1,4-butanediol. In all tests, nearly 100% selectivity to tetrahydrofuran was observed. After finding the most active catalyst, the kinetics of dehydration of 1,4-butanediol to tetrahydrofuran was studied over this material. The influence of operating parameters such as temperature, pressure, and... 

    Effect of potential on the early stage of nucleation and growth during aluminum electrocrystallization from molten salt (AlCl3-NaCl-KCl)

    , Article Journal of Electroanalytical Chemistry ; Volume 588, Issue 2 , 2006 , Pages 190-196 ; 15726657 (ISSN) Jafarian, M ; Mahjani, M. G ; Gobal, F ; Danaee, I ; Sharif University of Technology
    Elsevier  2006
    Abstract
    Electrodeposition of aluminum onto graphite from a molten electrolyte containing AlCl3-NaCl-KCl was studied by the method of chronoamperometery. In the early stage of the deposition and at low cathodic potentials two-dimensional (2D) nucleation and growth proceeding through instantaneous and a multitude of progressive steps followed the initial double layer charging. The processes are manifested as peaks on a decaying chronoamperogram. Non-linear fitting methods were applied to obtain the kinetic parameters in the light of Bewick, Fleischmann and Thirsk (BFT) theory. Under more cathodic potentials, transition from 2D to three-dimensional (3D) processes have been observed as manifested in the... 

    General reaction-diffusion processes with separable equations for correlation functions

    , Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics ; Volume 66, Issue 4 , 2002 , Pages 9- ; 1063651X (ISSN) Karimipour, V ; Sharif University of Technology
    2002
    Abstract
    We consider general multispecies models of reaction diffusion processes and obtain a set of constraints on the rates which give rise to closed systems of equations for correlation functions. Our results are valid in any dimension and on any type of lattice. We also show that under these conditions the evolution equations for two point functions at different times are also closed. As an example we introduce a class of two species models that may be useful for the description of voting processes or the spreading of epidemics. © 2002 The American Physical Society  

    Intracellular viral infection kinetics using a stochastic approach

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 38, Issue 4 , 2013 , Pages 359-376 ; 14686783 (ISSN) Taherkhani, F ; Taherkhani, F ; Rezania, H ; Akbarzadeh, H ; Sharif University of Technology
    2013
    Abstract
    Stochastic simulation is carried out to investigate intracellular viral reaction kinetics and the time evolution of the average particle number ( N̄) and coefficient variation (CV) for genome, template, and structural protein. The coefficient variation of these components is found to be ordered as: CV template > CV structural protein > CVgenome. The average particle number is also calculated via a deterministic approach. The magnitude value of the difference between the stochastic and deterministic approaches is found to be N̄ template ̃ N̄ structural protein > N̄ genome. The Poisson algorithm has been used to investigate the number of particles in the dynamics of intracellular viral... 

    Characterization and kinetics study of the photochlorination of polyethylene

    , Article Polymer Journal ; Volume 44, Issue 9 , 2012 , Pages 973-977 ; 00323896 (ISSN) Moradi, A ; Abadi, A. R. S ; Shahrokhi, M ; Sharif University of Technology
    Nature  2012
    Abstract
    The radical chlorination of polyethylene was carried out in perchloroethylene solvent using chlorine gas and ultraviolet photoradiation to investigate a reaction kinetics model. The recurrent structure of chloromethylene (-CHCl-) and methylene (-CH 2 -) groups and the percentage of substituted chlorine were determined using hydrogen-nuclear magnetic resonance (H-NMR) (500 MHz) spectra. A kinetics model has been proposed for this reaction in which the conversion of methylene (-CH 2 -) units to chloromethylene (-CHCl-) units was considered to be the main reaction step. The simplified version of the obtained kinetics model indicates that the reaction is first order with respect to the chlorine... 

    An investigation on the calcination kinetics of zinc carbonate hydroxide and Calsimin zinc carbonate concentrate

    , Article Chemical Engineering Journal ; Volume 121, Issue 2-3 , 2006 , Pages 79-84 ; 13858947 (ISSN) Nobari, A. H ; Halali, M ; Sharif University of Technology
    2006
    Abstract
    In this study the thermal calcination of two materials, high purity zinc carbonate hydroxide and the Calsimin zinc carbonate concentrate have been investigated. Isothermal studies have been performed on samples at different temperatures and times. Non-isothermal analysis has been carried out by TGA and DSC. It has been found that the calcination behaviour of both materials corresponds to the shrinking core model. The activation energy for the calcination of zinc carbonate hydroxide is found to be 88.7 kJ/mol, and that for the Calsimin sample is 97.3 kJ/mol. © 2006 Elsevier B.V. All rights reserved  

    Efficient Friedel-crafts alkylation of indoles and pyrrole with enones and nitroalkene in water

    , Article Organic and Biomolecular Chemistry ; 2006, Volume 4, Issue 23, Pages 4275-4277 Azizi, N. (Najmodin) ; Arynasab, F ; Saidi, M. R ; Sharif University of Technology
    Abstract
    An operationally simple and entirely green protocol for heteropoly acid catalyst conjugate addition of indoles and pyrrole to unsaturated carbonyl compounds and nitro-alkene in water was investigated. It is important that the products arising from 1,2-addition were not observed under the reaction conditions. Pyrroles also readily underwent Michael addition at Α-positions under the same reaction conditions. Indole and many of its derivatives are present in many substances commonly found in nature. Micheal addition reactions are performed in organic solvents with the reactions in water are relatively scarce. The Michael addition between indole and methyl vinyl ketone in the presence of... 

    Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: Improving and kinetic investigation

    , Article Journal of Environmental Health Science and Engineering ; 2013 , Volume 10, Issue 1 ; 2052336X (ISSN) Khorasani, A. C ; Mashreghi, M ; Yaghmaei, S ; Sharif University of Technology
    2013
    Abstract
    Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration... 

    In-situ Pb2+ remediation using nano iron particles

    , Article Journal of Environmental Health Science and Engineering ; Volume 13, Issue 1 , 2015 ; 2052336X (ISSN) Fadaei Tehrani, M. R ; Shamsai, A ; Vossughi, M ; Sharif University of Technology
    BioMed Central Ltd  2015
    Abstract
    Originally, application of nano zero valent iron (nZVI) particles for the removal of lead (Pb2+) in porous media was studied. At first, stabilized nZVI (S-nZVI) was prepared and characterized, then used in batch and continuous systems. Based on the batch experiments, corresponding reaction kinetics well fitted with the pseudo-first-order adsorption model, and reaction rate ranged from 0.01 to 0.04 g/mg/min depend on solution pH and the molar ratio between Fe and Pb. In batch tests, optimal condition with more than 90% removal efficiency at 60 min was observed at a pH range of 4 to 6 and Fe/Pb ratio more than 2.5. Continuous experiments exposed that Pb2+ remediation was as well influenced by... 

    Bi-amino surface functionalized nanoparticles: Synthesis and binary system dye removal from wastewater containing anionic dyes

    , Article Desalination and Water Treatment ; Volume 70 , 2017 , Pages 347-354 ; 19443994 (ISSN) Mahmoodi, N. M ; Ghezelbash, M ; Ghotbei, C ; Kazemeini, M ; Sharif University of Technology
    Desalination Publications  2017
    Abstract
    In this paper, copper oxide nanoparticle was synthesized, and its surface was modified using N-(2-aminoethyl)-3-(trimethoxysilyl)propylamine. The bi-amino surface functionalized nanoparticle (BASFN) was used to remove anionic dyes from single and binary systems. The scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDAX) and X-ray diffraction were used to characterize the nanoparticle. Direct Red 80 (DR80) and Direct Green 6 (DG6) were used as anionic dyes. The effect of adsorbent dosage, dye concentration and pH on dye removal was evaluated. Kinetic of dye adsorption on BASFN followed pseudo-second order. The results... 

    Nickel ion removal from aqueous solution using recyclable zeolitic imidazolate framework-8 (ZIF-8) nano adsorbent: A kinetic and equilibrium study

    , Article Desalination and Water Treatment ; Volume 103 , 2018 , Pages 141-151 ; 19443994 (ISSN) Roostan, Z ; Rashidi, A ; Borghei, S. M ; Sharif University of Technology
    Desalination Publications  2018
    Abstract
    The adsorption of nickel ions in an aqueous solution system was measured using zeolitic imidazolate framework-8 (ZIF-8) nanoadsorbent. ZIF-8 crystals were synthesized using the hydrothermal method. Nanoadsorbent was characterized by FTIR, XRD, SEM and N2 adsorption analysis. ZIF-8 crystals showed a high surface area of 1303 m2/g and particle size 100–150 nm. The Langmuir and Freundlich isotherms model were used to analyze the data. The sufficiently high R2 value of 0.996 resulted from the Langmuir isotherm model demonstrated the perfect performance of this model. The kinetic data were analyzed using the pseudo-first-order and pseudo-second-order models of types 1–4. Kinetic studies of the... 

    ZnO nanoparticles: An efficient nanocatalyst for the synthesis of β-acetamido ketones/esters via a multi-component reaction

    , Article Catalysis Communications ; Volume 9, Issue 2 , 2008 , Pages 299-306 ; 15667367 (ISSN) Mirjafary, Z ; Saeidian, H ; Sadeghi, A ; Matloubi Moghaddam, F ; Sharif University of Technology
    2008
    Abstract
    A convenient one-pot multi-component reaction of aromatic aldehydes, enolizable ketones or β-keto esters and acetonitrile in the presence of acetyl chloride and 10 mol% ZnO nanoparticles for the synthesis of β-acetamido ketones/esters at room temperature is described. © 2007 Elsevier B.V. All rights reserved  

    Solvent effects on kinetics of the reaction between 2-chloro-3,5- dinitropyridine and aniline in aqueous and alcoholic solutions of [bmim]BF 4

    , Article International Journal of Chemical Kinetics ; Volume 39, Issue 12 , December , 2007 , Pages 681-687 ; 05388066 (ISSN) Harifi Mood, A ; Habibi Yangjeh, A ; Gholami, M. R ; Sharif University of Technology
    2007
    Abstract
    Rate constants, kA. for the aromatic nucleophilic substitution reaction of 2-chloro-3,5-dinitropyridine with aniline were determined in different compositions of 1-(1-butyl)-3-methylimidazolium terafluoroborate ([bmim]BF4) mixed with water, methanol, and ethanol at 25°C. The obtained rate constants of the reaction in pure solvents are in the following order: water > methanol > ethanol > [bmim]BF4. In these solutions, rate constants of the reaction decrease with the mole fraction of the ionic liquid. Single-parameter correlations of log kA versus normalized polarity parameter (ETN), hydrogen bond acceptor basicity (β), hydrogen bond donor acidity (α), and dipolarity/polarizability (π*) do not... 

    Highly efficient synthesis of bis(indolyl)methanes in water

    , Article Journal of Molecular Catalysis A: Chemical ; Volume 275, Issue 1-2 , 2007 , Pages 109-112 ; 13811169 (ISSN) Azizi, N ; Torkian, L ; Saidi, M. R ; Sharif University of Technology
    2007
    Abstract
    A simple, atom economy and highly efficient green protocol have been developed for synthesis of bis(indolyl)alkane by the reaction of indole derivatives with aldehydes and ketones in the presence of small amount of the heteropoly acids in water. © 2007 Elsevier B.V. All rights reserved