فهرست مطالب

Catalysis - Volume:7 Issue: 4, Autumn 2017

Iranian Journal of Catalysis
Volume:7 Issue: 4, Autumn 2017

  • تاریخ انتشار: 1396/10/10
  • تعداد عناوین: 10
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  • Gaurav Rattan, Chirag Khullar *, Maninder Kumar Pages 249-255
    The present study deals with analysis of the activity of catalysts prepared by addition of different metals to Copper and Cobalt based catalysts for CO oxidation and the variation in activity caused by changes in composition. A series of catalysts were prepared with Cu:Co molar ratio 1:4 and a third metal (M= Ce, Ni, Au, Mg) was added in three different quantities. Compositions were prepared by coprecipitation method, calcinated at 550°C for three hours. The results reported that the cerium based catalysts showed the highest activity T100% = 390°C in terms of CO oxidation whereas gold based catalysts showed the least activity T58.24% = 418°C. The best selected catalyst of each group was characterized by the Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR).
    Keywords: CO Oxidation, Catalyst, Cu-Co, Cerium, Gold, Nickel, Magnesium
  • Farhad Shirini *, Tahereh Ghauri Koodehi, Omid Goli-Jolodar Pages 257-266
    This article describe the applicability of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2].2Cl) as a green, versatile and Brönsted acidic ionic catalyst in the promotion of the synthesis of phthalazine derivatives via one-pot three component reaction between aromatic aldehydes, 1,3-diketone derivatives and phthalhydrazide under solvent-free reaction conditions. The main advantages of this method are: (1) simplicity of the procedure, (2) solvent-free conditions, (3) availability of the starting materials, (4) high reaction rates and excellent yields, (5) reusability of the catalyst and (6) no column chromatographic of the products.
    Keywords: Br?nsted acidic ionic catalyst, Phthalazine derivatives, Solvent-free conditions
  • Sedigheh Rostami, Seyed Naser Azizi *, Fatemeh Rigi Pages 267-276
    Nano-sized protonated ZSM–5 ( H-ZSM-5nanozeolite) was successfully synthesized by the hydrothermal method using the bagasse ash (BGA) as a new silica source. Cultivated BGA in the south of the Caspian Sea (Mazandaran province, Iran) was used for extracting silica powder. H-ZSM-5 was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electronic microscopy (SEM) and Brunauer–Emmett–Teller (BET), Barrett-Joyner-Halenda (BJH) techniques. The catalytic activity of H-ZSM-5 nanozeolite was evaluated for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones via one-pot three-component reaction of aromatic aldehydes, 2-aminobenzothiazole or 2-aminobenzimidazole and isatoic anhydride under solvent-free conditions. Short reaction time, high yields, a simple experimental procedure in the absence of any toxic solvents and recovery of catalyst are the advantages of this protocol.
    Keywords: H-ZSM-5 nanozeolite, 2, 3-Dihydroquinazolin-4(1H)-ones, Hydrothermal, Bagasse, Catalyst
  • Alireza Heidarineko, Azar Bagheri Ghomi * Pages 277-282
    Nickel oxide (NiO) nano-size powder is synthesized using nickel (II) acetate tetrahydrate, sodium lauryl sulfate (SLS) and ammonia as precursors. Applied surfactant is anionic surfactant. The sample was characterized by FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM). The results obtained confirm the presence of nickel oxide nano-powders produced during chemical precipitation. Evaluation of the catalytic activity of developed nano-NiO particles were carried out using ultraviolet visible spectra. The uv-vis spectra obtained after ultraviolet irradiation in the presence of nickel oxide can indicate the degradation of tetracycline (TC) and dye Acid red -18 (ponceau 4R). The prepared NiO exhibits that 75% of Acid red -18 has been eliminated after 10 min.The results indicate that optimum concentration of NiO catalyst and the best pH for the degradation of AR were 0.5 g L-1 and pH 7, respectively. The best TC degradation results were obtained with 2 g L−1of the photocatalyst at pH 11.
    Keywords: Ammonia precipitation, NiO, Tetracycline, Ponceau 4R, Catalytic activity
  • Farzad Javadi, Reza Tayebee * Pages 283-292
    The synthesis of pharmaceutically and biologically active 2-amino-4H-chromenes was described using TiO2/nanoclinoptilolite (TiO2/NCP) as an efficient nanocatalyst under solvent-free condition. The TiO2/NCP was fabricated through modification of NCP with HDTMA, then the surface modified NCP was impregnated with titanium tetrachloride solution. Finally, the material incorporated with titanium was calcinated at 500 ºC and was characterized by FT-IR, ICP-OES, SEM, and XRD. The experimental conditions have been completely optimized and established, providing an increase in the rate and high yields. This procedure provides several merits such as a simple workup, economical, environmentally benign, short reaction time and excellent yields. Moreover, the prepared nanocomposite showed very high stability and reusability in the synthetic method under solvent-free and mild conditions.
    Keywords: TiO2-nanoclinoptilolite, 4H-chromene, Nanocomposite, Nanocatalyst, Solvent-free
  • Ali Allahresani * Pages 293-302
    In this study, novel CuO/g-C3N4 nanocomposite was simply synthesized by impregnation of g-C3N4 with CuO nanoparticles. Then, the heterogeneous catalyst was characterized by various techniques including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Moreover, the Friedel–Crafts 3-indolylation reaction of isatin with indole derivatives in water as a green solvent was investigated using catalytic amount of CuO/g-C3N4 nanocomposite. The results showed that di-indolyloxindole derivatives are synthesized in good to excellent yields at mild conditions. Finally, this method has some advantages including the use of water as a green solvent, short reaction time, room temperature, easy work up and excellent yields.
    Keywords: CuO-g-C3N4 nanocomposite, di-indolyloxindols, indole, isatin
  • Hossein Salavati *, Abbas Teimouri, Shahnaz Kazemi Pages 303-315
    In this research, Keggin-type polyoxometalate, H5PMoV2O40 (denoted as PMoV) was immobilized on modified NiFe2O4 nanoparticles to produce a magnetically separable catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), cyclic voltummetry (CV), energy dispersive X-ray (EDX) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The catalytic activity of synthesized catalyst in oxidation of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2) was investigated using H2O2 as an oxidant and acetonitrile as an extractant. The catalyst could be readily separated from the catalytic system using the magnetic field; and loss of activity was negligible when the catalyst was recovered in five consecutive runs. The effects of main process variables including H2O2 amount (mmol), reaction temperature (°C) and reaction time (min) were analyzed by response surface methodology (RSM) based on the central composite design (CCD). The optimal condition for conversion of DBT was found to be H2O2 2.8 mmol, reaction temperature 42°C and reaction time 57 min for 0.1 g of catalyst dosage. The conversion of DBT to DBTO2 under optimized conditions was 85.9 %. Moreover, the dibenzothiophene sulfone product was characterized by NMR, FT-IR, Mass and GC analysis.
    Keywords: Heteropolyacid, Magnetic nanoparticles, Oxidation, Supported catalyst
  • Hamid Reza Pouretedal *, Mohammad Fallahgar, Fahimeh Sotoudeh Pourhasan, Mohammad Nasiri Pages 317-326
    Taguchi experimental design technique was used for optimization of photodegradation of yellow water sample of trinitrotoluene (TNT) production process. The nanoparticles of doped N-TiO2 were also used as photocatalysts in the photodegradation reaction under visible light. The ranking of data based on signal to noise ratio values showed that the importance order of the factors affecting the degradation efficiency was: the nature of photocatalyst > time of photodegradation > amount of photocatalyst > initial concentration of pollutant. The optimized conditions were photocatalyst of TiO2/N0.1 photocatalyst dosage of 1.5 g L-1 and dilution times of 750 for real samples. The photocatalyst of TiO2/N0.1 was analyzed by BET surface analysis, X-ray diffraction pattern, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectra (DTS). Relatively high surface area of 150 m2×g-1, anatase/rutile structure, approximately uniform distribution of nanoparticles size and band-gap energy of 2.92 eV were measured for TiO2/N0.1 nanophotocatalyst. A linear model with the regression coefficient (R2) of 0.887 was obtained by the multiple linear regression analysis. The proposed model was "Degradation efficiency (Y) = 20.492 1.461 X1 6.330 X2 0.014 X3 2.291 X4". The obtained P-values in the confidence level of 95% were
    Keywords: Taguchi method, Doped TiO2 nanophotocatalyst, Yellow water, Photodegradation
  • Mohammad Hossein Nobahari, Ahmad Nozad Golikand *, Mojtaba Bagherzadeh Pages 327-335
    The impregnation method was used to synthesize Pt and Pt3Co supported on MWCNTs applying NaBH4 as the reducing agent. The structure, morphology, and chemical composition of the electrocatalysts were characterized through SEM, XRD, and EDX. X-ray diffraction showed a good crystallinity of the supported Pt nanoparticles on the composites and showed the formation of Pt3Co alloy. The SEM images revealed that the particles of Pt3Co were deposited uniformly on the surface of MWCNT with a diameter of 10 nm. EDX analysis confirmed the surface segregation of Co and Pt occurred (1:3 surface atomic ratio Pt-Co) for the Pt3Co/MWCNT nanocomposite. The Pt3Co/MWCNTs and Pt/MWCNTs electrocatalysts’ electrochemical performance was assessed against the methanol oxidation reaction (MOR) in 0.5 M H2SO4 solution using the chronoamperometry (CA) and the cyclic voltammetry (CV) methods. The minimum onset potential and the largest oxidation current density were obtained at Pt3Co/MWCNTs electrocatalyst. The Pt3Co/MWCNT catalyst with a good alloying degree has been shown to have better anti-poisoning ability, electrochemical activity, and long-term durability than Pt/MWCNT catalysts, approved by the bimetallic catalysts’ bi-functional mechanism.
    Keywords: Pt3Co electrocatalyst, Methanol oxidation reaction, Electrochemical activity, Direct methanol fuel cells
  • Prabhakar Shrivas, Nitesh Punyapreddiwar, Atul Wankhade, Sangesh Zodape, Umesh Pratap* Pages 337-340
    The C-C bond formation is an important reaction in organic synthesis to obtain value-added intermediates. Therefore, in this paper an attempt has been made to accelerate the Henry reaction (C-C bond formation) between aryl aldehydes and nitromethane using less expensive whole cell biocatalyst, baker’s yeast (BY). The scope of the methodology was also tested for the heteryl aldehyde i.e. 2-chloro-3-formyl quinoline to obtain the corresponding quinoline containing nitroalcohol. The developed protocol is highly efficient and completely environmentally friendly. The work addressed the issue of non-aqueous biocatalysis, since Henry reaction catalysed by baker's yeast has been carried out in ethanol.
    Keywords: Baker's yeast, Biocatalysis, Henry reaction, β-Nitroalcohol