Search for: oxides
Total 2196 records
Immobilization of dioxomolybdenum(VI) schiff base complex on graphene oxide nanosheets and its catalytic activity for oxidation of sulfides, Article Journal of Coordination Chemistry ; Volume 70, Issue 17 , 2017 , Pages 2986-2998 ; 00958972 (ISSN) ; Karimi, H ; Amini, M ; Sharif University of Technology
Graphene oxide was an effective supporting material for immobilizing a dioxomolybdenum Schiff base complex via covalent interaction. The large surface of graphene oxide plays important roles to obtain a good degree of catalytic reaction. Catalytic capacity of the graphene-bound dioxomolybdenum Schiff base complex was investigated for the oxidation of various sulfides to sulfoxide compounds using hydrogen peroxide urea as an oxidant. The catalyst was characterized by various techniques including XRD, FTIR, TGA, SEM, UV–vis, and ICP-AES. The immobilized complex was very efficient with the extra benefits of easy recovery and recycling of the heterogeneous catalyst. The graphene oxide bound...
Article Transactions of the Indian Institute of Metals ; Volume 73, Issue 4 , 2020 , Pages 989-997 ; Mojtahedi, B ; Yoozbashizadeh, H ; Sharif University of Technology
In this study, chalcopyrite concentrate produced in Sarcheshmeh copper plant was subjected to oxidative leaching investigation by cupric ion to determine the effect of several parameters on the copper and iron dissolution, including temperature of leaching, time of holding and cupric concentration as oxidant agent in a range of 38–97 °C, 1.5–8.5 h and 0.2–0.8 M, respectively. The leaching media was chloride providing with 3 M HCl 37% and CuCl2. The experiments were designed by central composite design method. The dissolution of copper and iron was examined. The maximum dissolution of copper 62.64%, was obtained at 85 °C, 7 h and oxidant concentration of 0.7 M. The kinetics model of...
Article Hydrocarbon Processing ; Volume 88, Issue 3 , 2009 ; 00188190 (ISSN) ; Farhadi, F ; Sharif University of Technology
Gulf Publishing Company 2009
Article Journal of Coordination Chemistry ; Volume 62, Issue 20 , 2009 , Pages 3384-3390 ; 00958972 (ISSN) ; Tangeysh, B ; Sharif University of Technology
The effect of CoSALEN on anti-oxidative properties of fullerene C60 in the presence of O2 in cumene was investigated. A comparison was made between the role of the CoSALEN as a catalyst in the C60 oxidation and oxidation in the presence of an initiator, i.e., AIBN. A mechanism is proposed for the catalytic role of CoSALEN in oxidation of C60. Oxidation of octadecylaminofullerene C60 at the same conditions reveals that oxidation could be a result of hydroperoxidation of the unreacted sites of C60. We conclude that C60 as well as its aminoderivatives enhance the efficiency of CoSALEN in the oxidation of cumene due to their radical scavenging property of their unreacted double-bond sites. ©...
Article Journal of Solution Chemistry ; Volume 36, Issue 5 , 2007 , Pages 595-604 ; 00959782 (ISSN) ; Boghaei, D. M ; Sharif University of Technology
Equilibrium constants for formation of a cobalt(II) complex with the bidentate ligand dopamine have been studied with spectrophotometric methods in water + ethanol cosolvent systems at 15, 25, and 35 (±0.1)∈°C and an ionic strength of 0.2 mol·dm-3. The ionic strength was maintained using sodium chloride and a phosphate buffer. The stability constants of the complex and the resulting Gibbs energy changes are obtained. The results are discussed in terms of the effect of solvent on protonation and complexation. © Springer Science+Business Media, LLC 2007
Article Minerals Engineering ; Volume 17, Issue 4 , 2004 , Pages 545-552 ; 08926875 (ISSN) ; Rezai, B ; Vossoughi, M ; Osanloo, M ; Abdollahi, M ; Sharif University of Technology
A sample of Tabas coal from Iran was oxidized using air, peroxyacetic acid (PAA), and PAA+air as a pretreatment for desulfurization with sodium butoxide in a batch reactor. The effects of air oxidation temperature, PAA oxidation time, sodium butoxide reaction time and temperature, solvent concentration and particle size on the reduction of sulfur were investigated. The PAA+air oxidation pretreatment was the most effective method for enhancing sulfur removal. This procedure increased pyritic sulfur removal by approximately 15% and organic sulfur removal by 20% in leaching with sodium butoxide. Increasing the temperature from 25 (unoxidized) to 100 °C on air oxidized samples, increased sulfur...
Synthesis and Optimization of Metal Oxide Catalysts Supported on Nano-structured Alumina for Oxidation of Toluene from Contaminated Air, M.Sc. Thesis Sharif University of Technology ; Khorashe, Farhad ; Kazemeni, Mohammad
Exhaust gases from poultry rendering facilities contain volatile organic compounds (VOCs) that are a nuisance, odorous, and smog and particulate matter precursors. Other available treatment options, such as thermal and catalytic incineration require temperature intensive inputs and form additional greenhouse gases. Hence, an inexpensive alternative technology is needed to eliminate these air pollutants. This research investigated the catalytic oxidation of toluene vapors using novel dispersed nano catalysts derived from new preparation method. The combined impregnation (IMP) and deposition-precipitation (DP) was used to prepare supported transition metal oxide catalyst over commercial and...
Synthesis of NO-bidentate- and ONO-Tridentate-Oxovanadium(IV) Complexes Supported on Fe¬3O4@SiO2 Core-Shell Magnetic Nanoparticle and Their Application in Oxidation of Sulfides and Alkenes
Sharif University of Technology
To synthesizeFe3O4@SiO2 core-shellnanoparticles,at first,Fe3O4 magnetic nanoparticle synthesisedby usingcoprecipitation method.Then tetraethyl orthosilicate (TEOS) was used to coverthe surface of this nanoparticle with layer of silica. In the next step, the surface of Fe3O4@SiO2 core-shellnanoparticlesfunctionalized by NO-bidentate and ONO-tridentate ligands. Finally the functionalized nanoparticle coordinated to oxovanadium(IV) to achieve Fe3O4@SiO2@NO-VO2+ and Fe3O4@SiO2@ONO-VO2+nanocatalysts for selective oxidation of sulfides to corresponding sulfoxide and oxidation of alkene. FT-IR, 1HNMR, 13CNMR, SEM, VSM and ICP analysis were used for characterization of this nanocatalysts. This...
Article International Journal of Hydrogen Energy ; Volume 39, Issue 15 , 15 May , 2014 , Pages 8169–8179 ; Iraji Zada, A. (Azam) ; Akhavana, O. (Omid) ; Ghasemic, S. (Shahnaz) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
Pd–WO3 nanostructures were incorporated on graphene oxide (GO) and partially reduced graphene oxide (PRGO) sheets using a controlled hydrothermal process to fabricate effective hydrogen gas sensors. Pd–WO3 nanostructures showed ribbon-like morphologies and Pd–WO3/GO presented an irregular nanostructured form, while Pd–WO3/PRGO exhibited a hierarchical nanostructure with a high surface area. Gas sensing properties of thin films of these materials were studied for different hydrogen concentrations (from 20 to 10,000 ppm) at various temperatures (from room temperature to 250 °C). Although adding GO in the Pd–WO3, after hydrothermal process could increase the film conductivity, gas sensitivity...
Article International Journal of Hydrogen Energy ; 2021 ; 03603199 (ISSN) ; Ahmad, I ; Rashid, N ; Zafar, M. N ; Shehzad, F. K ; ullah, Z ; Ul-Hamid, A ; Nazar, M.F ; Junaid, M ; Faheem, M ; Shafqat, S. S ; Jabeen, U ; Dahshan, A ; Sharif University of Technology
Elsevier Ltd 2021
The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to...
Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 21, Issue 2 , 2002 , Pages 71-73 ; 10219986 (ISSN) ; Ahmadibeni, Y ; Sharif University of Technology
The polymer supported hypochlorite ion is a facile selective oxidizing agent for the oxidation of various alcohols to aldehydes and ketones. Similarly it successfully oxidizes various Hantzsch type 1,4 - dihydropyridines to corresponding pyridines
Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications [electronic resource], Article Nanotechnology ; February 2012, Vol. 23, No. 4, PP. 045102 ; Imani, Mohammad ; Yousefi, Mohammad ; Galinetto, Pietro ; Simchi, Abdolreza ; Amiri, Houshang ; Stroeve, Pieter ; Mahmoudi, Morteza ; Sharif University of Technology
Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles such as titanium oxide can be coated by pyrolytic carbon (PyC) and that the coating has cytocompatible properties. Pyrolization and condensation of methane formed a thin layer of pyrolytic carbon on the titanium oxide core. The formation of the PyC shell retards coalescence and sintering of the ceramic phase. Our MTT assay shows that the PyC-coated particles are cytocompatible at employed doses
An experimental and computational study on the rate constant of electrochemically generated N-acetyl-p- quinoneimine with dimethylamine, Article International Journal of Electrochemical Science ; Volume 3, Issue 10 , 2008 , Pages 1092-1107 ; 14523981 (ISSN) ; Haqgu, M ; Nematollahi, D ; Gholami, R. M ; Sharif University of Technology
Electrochemical oxidation of acetaminophen (N-acetyl-p-aminophenol) (1) has been studied in the presence of dimethylamine (2) as a nucleophile in aqueous solution, by means of cyclic voltammetry and controlled-potential coulometry. The results indicate the participation of electrochemically generated N-acetyl-p-quinoneimine (1a) in Michael reaction with dimethylamine (2). Based on ECE mechanism, the observed homogeneous rate constant (kobs) of the above mentioned reaction is estimated by comparing the experimental cyclic voltammograms with the digital simulated results. Further more; kinetics and mechanism of the reaction were studied with ab initio calculation, Monte Carlo and QM/MM...
Sodium hypochlorite/montmorillonite K10: An effective oxidant for the oxidation of thiols to disulfides, Article Letters in Organic Chemistry ; Volume 2, Issue 5 , 2005 , Pages 485-486 ; 15701786 (ISSN) ; Rahimi, A ; Karimi Jaberi, Z ; Sharif University of Technology
Sodium hypochlorite adsorbed on montmorillonite K10 is a useful oxidant for the oxidation of thiols to disulfides under the room temperature. © 2005 Bentham Science Publishers Ltd
Article Journal of the Brazilian Chemical Society ; Volume 16, Issue 5 , 2005 , Pages 1082-1084 ; 01035053 (ISSN) ; Eftekhari Sis, B ; Khalili, B ; Karimi Jaberi, Z ; Sharif University of Technology
Sociedade Brasileira de Quimica 2005
Phenols were oxidized to quinones using sodium perborate (SPB) on wet montmorillonite as oxidant. The reaction was carried out at ambient temperature on the solid phase under solvent free conditions. ©2005 Sociedade Brasileira de Química
Microwave assisted selective oxidation of benzylic alcohols with calcium hypochlorite under solvent-free conditions, Article Monatshefte fur Chemie ; Volume 132, Issue 5 , 2001 , Pages 655-658 ; 00269247 (ISSN) ; Saidi, M. R ; Bolourtchian, M ; Shirzi, J. S ; Sharif University of Technology
A remarkably fast microwave assisted selective oxidation of benzylic alcohols with calcium hypochlorite under solvent-free conditions is described
De Gruyter 2018
Article Applied Surface Science ; Volume 256, Issue 24 , 2010 , Pages 7596-7599 ; 01694332 (ISSN) ; Iraji Zad, A ; Sharif University of Technology
A density functional theory (DFT) study of graphene synthesis from graphite oxidation and exfoliation is presented. The calculated DFT results for O adsorption predict CO as a most stable bond on the graphene oxide (GO) sheet. The obtained exfoliation energy for the graphene and the GO are 143 and ∼70 mJ/m2 that verify easier exfoliation of the graphite oxide compared with the graphite. Furthermore, the DFT results show that for decreasing the exfoliation energy of the GO at least two layers of the graphite should be oxidized during the oxidation process
Article Journal of Applied Electrochemistry ; Volume 36, Issue 8 , 2006 , Pages 913-918 ; 0021891X (ISSN) ; Moghaddam, R. B ; Mahjani, M. G ; Gobal, F ; Sharif University of Technology
The electro-catalytic oxidation of methanol on a Ni-Cu alloy (NCA) with atomic ratio of 60/40 having previously undergone 50 potential sweep cycles in the range 0-600 mV vs. (Ag/AgCl) in 1 m NaOH was studied by cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (EIS). The electro-oxidation was observed as large anodic peaks both in the anodic and early stages of the cathodic direction of potential sweep around 420 mV vs. (Ag/AgCl). The electro-catalytic surface was at least an order of magnitude superior to a pure nickel electrode for methanol oxidation. The diffusion coefficient and apparent rate constant of methanol oxidation were found to be 2.16 × 10-4 cm2 s-1 and...
Designing of Magnetic Nanocatalyst and their Application in Oxidation of Alcohols and Other Functional Groups, Ph.D. Dissertation Sharif University of Technology ; Mahmoodi Hashemi, Mohammad
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...