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    Simple methodology for the aerobic N-methylation of substituted anilines catalyzed by zirconium oxychloride octahydrate, ZrOCl2·8H 2O

    , Article Industrial and Engineering Chemistry Research ; Volume 52, Issue 32 , 2013 , Pages 11001-11006 ; 08885885 (ISSN) Tayebee, R ; Rezaei Seresht, E ; Jafari, F ; Rabiei, S ; Sharif University of Technology
    A highly chemoselective methodology is described for the N-methylation of functionalized anilines with dimethyl carbonate (MeOCO2Me, DMC) in the presence of ZrOCl2·8H2O. Dimethyl carbonate, which usually promotes methylation at T > 120 C and eventually under inert atmosphere, was activated in the presence of zirconium oxychloride for the desired transformation at 90 C under aerobic conditions. Aminophenols showed good reactivity in this transformation and produced the corresponding N-methylanilines, as the major products, with high selectivity. Catalyst reusability study confirmed that ZrOCl2·8H2O is a recyclable catalyst and its catalytic activity was remained unchanged at least after eight... 

    Conjugated linoleic acid production and optimization via catalytic reaction method using safflower oil

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 8 , 2018 , Pages 1166-1171 ; 1728144X (ISSN) Afarin, M ; Alemzadeh, I ; Kouchak Yazdi, Z ; Sharif University of Technology
    Materials and Energy Research Center  2018
    Conjugated linoleic acid (CLA) is one of the most physiological active fatty acids due to its positive effect on prevention of diseases such as obesity, hyperlipidemia, atherosclerosis and cancer. The aim of this study was to optimize the production of conjugated linoleic acid (CLA)% in alkali isomerization of safflower oil including 71% linoleic acid (LA) using response surface methodology (RSM). The effect of three reaction variables such as temperature, reaction time and amount of KOH on CLA production was investigated using design-expert software. The optimal condition determined at this point, 72% total CLA with the yield of 84% temperature reaction time and the amount of KOH were 187.6... 

    Novel cationic-modified salep as an efficient flocculating agent for settling of cement slurries

    , Article Carbohydrate Polymers ; Volume 93, Issue 2 , April , 2013 , Pages 506-511 ; 01448617 (ISSN) Pourjavadi, A ; Fakoorpoor, S. M ; Hosseini, S. H ; Sharif University of Technology
    A new cationic flocculant was synthesized by graft copolymerization of acrylamide (AM) and 3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) onto salep using free radical polymerization initiated by ammonium persulfate (APS) to produce cationic salep [S-g-P(AM-co-MAPTAC)]. Reaction parameters (monomers/salep ratio, concentration of reactants, MAPTAC/AM ratio, and APS) were optimized using a full factorial experimental design to obtain the highest settling rate for cement suspensions. The best performing product was characterized by gel permeation chromatography (GPC), FTIR, 1H NMR spectroscopy, and thermogravimetric analysis (TGA). The resulted cationic flocculant may be... 

    Polyoxometalate-supported Pd nanoparticles as efficient catalysts for the Mizoroki-Heck cross-coupling reactions in PEG medium

    , Article Applied Organometallic Chemistry ; Volume 34, Issue 1 , 2020 Bagherzadeh, M ; Hosseini, H ; Salami, R ; Sharif University of Technology
    John Wiley and Sons Ltd  2020
    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... 

    Laboratory Investigation of the Effective Pparametrs on the Particle Size Distribution at the Nanoscale During the Synthesis of Zirconium Oxide Powder and the Effectiveness of each on the Uniform Distribution of the Particle Size of the Final Powder

    , M.Sc. Thesis Sharif University of Technology Bagheran, Sevda (Author) ; Ghotbi, Cyrus (Supervisor) ; Fotovat, Farzam (Supervisor) ; Malek Khachatourian, Adrineh (Supervisor)
    Reaction parameters in precipitation processes have a significant impact on the product characteristics. The process of formation of yttrium-stabilized zirconia precipitates was studied by co-precipitation method to investigate the parameters affecting particle size distribution. These studies aimed to investigate the reaction parameters and determine their effect on the size of the particles, taking into account the effects caused by the interaction of the parameters. To achieve this goal, the design of the experiment based on response surface methodology was used and five parameters of zirconyl chloride concentration, molar percentage of yttrium oxide, reaction time, mass percentage of... 

    Salep-g-poly(sodium acrylate)/alumina as an environmental-sensitive biopolymer superabsorbent composite: Synthesis and investigation of its swelling behavior

    , Article Advances in Polymer Technology ; Volume 31, Issue 1 , 2012 , Pages 41-51 ; 07306679 (ISSN) Bardajee, G. R ; Pourjavadi, A ; Soleyman, R ; Ghavami, S ; Sharif University of Technology
    A novel kind of a biopolymer-based superabsorbent composite, salep-g-poly(sodium acrylate)/alumina, was prepared from salep, sodium acrylate, and alumina by aqueous polymerization, using N,N'-methylenebisacrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator. The reaction parameters [i.e., acrylic acid (AA), MBA, APS amounts, and neutralization percentage of AA as well as alumina/salep weight ratio] affecting the water absorbency of the hydrogel composite were optimized using systematic method to achieve a composite with high swelling capacity as possible. The swelling behavior of optimum superabsorbent composite was measured in various pH solutions. In addition,... 

    Effect of chemical treatment of Teflon powder on the properties of polyamide 66/Teflon composites prepared by melt mixing

    , Article Macromolecular Research ; Volume 19, Issue 6 , June , 2011 , Pages 613-621 ; 15985032 (ISSN) Shojaei, A ; Gholamalipour, S ; Sharif University of Technology
    The surface defluorination of Teflon in powdery form was performed using a chemical treatment. The reaction parameters including the reaction time, sodium, naphthalene concentrations were optimized using a Taguchi method to obtain maximum functionality on the particles surface. The surface functionality of the treated particles was analyzed by FTIR, energy dispersive X-ray analysis (EDX) and surface energy. Both treated (g-PTFE) and untreated (PTFE) Teflon were added to polyamide 66 (PA66) at various loadings up to 6 wt%. Mechanical, differential scanning calorimetry (DSC) and tribological analyses for different PA66/Teflon composites were carried out. The chemical treatment enhanced the... 

    The effects of reaction conditions on block copolymerization of chitosan and poly(ethylene glycol)

    , Article Carbohydrate Polymers ; Volume 81, Issue 4 , July , 2010 , Pages 799-804 ; 01448617 (ISSN) Ganji, F ; Abdekhodaie, M. J ; Sharif University of Technology
    A novel injectable in situ gelling thermosensitive chitosan-block-poly(ethylene glycol) formulation was synthesized for drug delivery applications. Block copolymerization of monomethoxy-poly(ethylene glycol) onto chitosan using potassium persulfate as an initiator was carried under a nitrogen atmosphere in aqueous solution. The effects of potassium persulfate and poly(ethylene glycol) concentrations, reaction time and reaction temperature on block polymerization were studied by determining the yield of reaction (%Y), polymerization efficiency (%E) and add-on percentage (%Add-on). Keeping the other conditions constant, the optimum reaction conditions were found to be initiator = 0.01 M,... 

    γ-irradiation synthesis of a smart hydrogel: Optimization using taguchi method and investigation of its swelling behavior

    , Article Scientia Iranica ; Volume 17, Issue 1 C , June , 2010 , Pages 15-23 ; 10263098 (ISSN) Pourjavadi, A ; Soleyman, R ; Bardajee, Gh. R ; Seidi, F ; Sharif University of Technology
    In the current work, synthesis of an environmental-sensitive superabsorbent hydrogel using γ-rays is described. Grafted polyacrylonitrile onto a homogeneous solution of starch and kappa-Carrageenan hybrid backbones created a smart material with reversible behavior. The reaction parameters (i.e. acrylonitrile, starch and kappa-Carrageenan concentration, as well as γ-irradiation time) affecting the. water absorbency of the. hydrogel were optimized using the. Taguchi method, in order to achieve a hydrogel with high swelling capacity. FTIR spectroscopy was used for confirming the. structure of the final product and the morphology of the synthesized hydrogel was examined by a scanning electron... 

    Novel salep-based chelating hydrogel for heavy metal removal from aqueous solutions

    , Article Polymers for Advanced Technologies ; Volume 27, Issue 8 , 2016 , Pages 999-1005 ; 10427147 (ISSN) Soleyman, R ; Pourjavadi, A ; Monfared, A ; Khorasani, Z ; Sharif University of Technology
    John Wiley and Sons Ltd 
    A novel optimized chelating hydrogel was synthesized via graft copolymerization of acrylamide and 2-hydroxyethyl methacrylate (as two-dentate chelating co-monomer) onto salep (a multicomponent polysaccharide obtained from dried tubers of certain natural terrestrial orchids) using N,N′-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. Reaction parameters (N,N′-methylenebisacrylamide and ammonium persulfate amounts as well as acrylamide/2-hydroxyethyl methacrylate weight ratio) affecting the water absorption of the chelating hydrogel were optimized using a systematic method to achieve a hydrogel with high swelling capacity as possible. Heavy metal ion adsorption... 

    Synthesis and characterization of MoO3 nanostructures by solution combustion method employing morphology and size control

    , Article Journal of Nanoparticle Research ; Volume 12, Issue 4 , 2010 , Pages 1509-1521 ; 13880764 (ISSN) Parviz, D ; Kazemeini, M ; Rashidi, A. M ; Jafari Jozani, Kh ; Sharif University of Technology
    Molybdenum oxide nanostructures were synthesized utilizing the solution combustion method where the ammonium molybdate powder and an organic additive were used as precursors. Different organic additives including ethylene diamine tetraacetic acid (EDTA), polyethylene glycol 200 (PEG 200), sorbitol and urea were used as surfactants in order to investigate the effect of additive structure on morphology and particle size of products. Also various reaction parameters such as the additive/Mo molar ratio, concentration of metal ion in solution, pH of the reaction, and temperature of the synthesis media were changed to study effects on product morphology and size. Outcomes were characterized by...