Search for: chemical-reaction-kinetics
0.008 seconds

    Highly efficient ring opening reactions of epoxides with deactivated aromatic amines catalyzed by heteropoly acids in water

    , Article Tetrahedron ; Volume 63, Issue 4 , 2007 , Pages 888-891 ; 00404020 (ISSN) Azizi, N ; Saidi, M. R ; Sharif University of Technology
    Heteropoly acid was found to be an effective and efficient catalyst for the ring opening reaction of epoxides with various aromatic amines to produce the corresponding β-amino alcohols in moderate to excellent yields in water. This method provides a new and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst, and simple work-up procedure. © 2006  

    Evolution of microstructure of nickel base superalloy at high temperatures

    , Article Materials Science and Technology ; Volume 22, Issue 8 , 2006 , Pages 888-898 ; 02670836 (ISSN) Safari, J ; Nategh, S ; McLean, M ; Sharif University of Technology
    The evolution of primary and secondary γ′ precipitates in the high γ′ volume fraction Rene 80 Ni based superalloy has been examined during aging at elevated temperatures for periods up to 1750 h. While the increase in average dimension of particles followed the cube rate Lifshitz, Slypzof and Wagner (LSW) law, rt-3-r0 -3=kt, there were significant discrepancies between the experimental and theoretical particle size distributions (PSDs) and inconsistency with the kinetic constants associated with the two populations of particles. These differences are attributed to the influence of elastic coherency strains which have not been considered in conventional capillarity driven coarsening models.... 

    M: XNi100- X (M = Ag, and Co) nanoparticles supported on CeO2 nanorods derived from Ce-metal organic frameworks as an effective catalyst for reduction of organic pollutants: Langmuir-Hinshelwood kinetics and mechanism

    , Article New Journal of Chemistry ; Volume 41, Issue 19 , 2017 , Pages 10948-10958 ; 11440546 (ISSN) Kohantorabi, M ; Gholami, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2017
    In this study, AgxNi100-x, and CoxNi100-x (x = 0, 20, 40, 60, 80, and 100) bimetallic nanoparticles were successfully decorated on the surface of CeO2 nanorods derived from Ce-metal organic frameworks (Ce-MOF). The as-synthesized products were characterized using different techniques including XRD, FE-SEM, EDX, TEM, ICP, and BET. The as-prepared nanocomposites showed remarkable catalytic activity towards the reduction of organic pollutants such as 4-nitrophenol (4-NP), and rhodamine-B dye (RhB) by NaBH4 solution, with high stability and reusability for five consecutive cycles. The obtained results indicated that among these nanocomposites, Ag80Ni20@CeO2, and Co60Ni40@CeO2 exhibited the best... 

    Mechanisms and kinetics of Thiotepa and tepa hydrolysis: DFT study

    , Article Journal of Molecular Modeling ; Volume 18, Issue 8 , 2012 , Pages 3563-3576 ; 16102940 (ISSN) Torabifard, H ; Fattahi, A ; Sharif University of Technology
    Springer  2012
    N,N′,N″-triethylenethiophosphoramide (Thiotepa) and its oxo analogue (Tepa) as the major metabolite are trifunctional alkylating agents with a broad spectrum of antitumor activity. In vivo and vitro studies show alkylation of DNA by Thiotepa and Tepa can follow two pathways, but it remains unclear which pathway represents the precise mechanism of action. In pathway 1, these agents are capable of forming cross-links with DNA molecules via two different mechanisms. In the first mechanism, the ring opening reaction is initiated by protonating the aziridine, which then becomes the primary target of nucleophilic attack by the N7-Guanine. The second one is a direct nucleophilic ring opening of... 

    The agglomeration kinetics of aluminum hydroxide in Bayer process

    , Article Powder Technology ; Volume 224 , July , 2012 , Pages 351-355 ; 00325910 (ISSN) Bahrami, M ; Nattaghi, E ; Movahedirad, S ; Ranjbarian, S ; Farhadi, F ; Sharif University of Technology
    The effects of temperature, seed mass and agitation rate on agglomeration kinetics of aluminum hydroxide in Bayer process have been studied in a batch system. Collected raw data were analyzed and the kinetics data of agglomeration were derived through simulation of the process using a pre-developed software. The results showed that agglomeration kinetics constant (agglomeration kernel) increases with increase in temperature and agitation rate. Moreover a maximum value of agglomeration rate versus added seed mass was observed. Furthermore the magnitude of calculated activation energy of agglomeration was close to that of growth  

    Tailoring dicobalt pacman complexes of schiff-base calixpyrroles towards dioxygen reduction catalysis

    , Article Chemical Communications ; Volume 46, Issue 5 , 2010 , Pages 710-712 ; 13597345 (ISSN) Askarizadeh, E ; Bani Yaghoob, S ; Boghaei, D. M ; Slawin, A. M. Z ; Love, J. B ; Sharif University of Technology
    By modifying the mouth of a macrocyclic dicobalt Pacman complex, it is possible to both isolate new bridging-superoxo and hydroxyl complexes and to tune the reactivity of this system towards catalytic four-electron reduction of dioxygen to water  

    A new detection chamber design on centrifugal microfluidic platform to measure hemoglobin of whole blood

    , Article SLAS Technology ; Volume 26, Issue 4 , 2021 , Pages 392-398 ; 24726303 (ISSN) Mahmodi Arjmand, E ; Saadatmand, M ; Eghbal, M ; Bakhtiari, M. R ; Mehraji, S ; Sharif University of Technology
    SAGE Publications Inc  2021
    Undoubtedly, microfluidics has been a focal point of interdisciplinary science during the last two decades, resulting in many developments in this area. Centrifugal microfluidic platforms have good potential for use in point-of-care devices because they take advantage of some intrinsic forces, most notably centrifugal force, which obviates the need to any external driving forces. Herein, we introduce a newly designed detection chamber for use on microfluidic discs that can be employed as an absorbance readout step in cases where the final solution has a very low viscosity and surface tension. In such situations, our chamber easily eliminates the air bubbles from the final solution without... 

    Numerical modeling of surface reaction kinetics in electrokinetically actuated microfluidic devices

    , Article Analytica Chimica Acta ; Vol. 838, issue , August , 2014 , pp. 64-75 ; ISSN: 00032670 Sadeghi, A ; Amini, Y ; Saidi, M. H ; Chakraborty, S ; Sharif University of Technology
    We outline a comprehensive numerical procedure for modeling of species transport and surface reaction kinetics in electrokinetically actuated microfluidic devices of rectangular cross section. Our results confirm the findings of previous simplified approaches that a concentration wave is created for sufficiently long microreactors. An analytical solution, developed for the wave propagation speed, shows that, when normalizing with the fluid mean velocity, it becomes a function of three parameters comprising the channel aspect ratio, the relative adsorption capacity, and the kinetic equilibrium constant. Our studies also reveal that the reactor geometry idealized as a slit, instead of a... 

    Direct conversion of inorganic complexes to platinum/thin oxide nanoparticles decorated on MOF-derived chromium oxide/nanoporous carbon composite as an efficient electrocatalyst for ethanol oxidation reaction

    , Article Journal of Colloid and Interface Science ; Volume 555 , 2019 , Pages 655-666 ; 00219797 (ISSN) Kamyar, N ; Rezaee, S ; Shahrokhian, S ; Amini, M. M ; Sharif University of Technology
    Academic Press Inc  2019
    In this work, we present the design and fabrication of a novel nanocomposite based on noble metal and metal oxide nanoparticles dispersed on highly porous carbon obtained via the pyrolysis of an inorganic complex and metal-organic frameworks. This nanocomposite is prepared by a two-step procedure: first, the composite support of nanoporous carbon (NPC) is obtained by the direct carbonization of the Cr-benzene dicarboxylic ligand (BDC) MOF in an Argon atmosphere at 500 °C (Cr2O3-NPC). A mixture containing Cr2O3-NPC and [PtCl(SnCl3)(SMe2)2] is then prepared, and underflow of Argon is heated to 380 °C. Finally, Pt-SnO2 nanoparticles are loaded on the Cr2O3-NPC support, and the obtained...