فهرست مطالب

new Chemistry - Volume:5 Issue:4, 2018
  • Volume:5 Issue:4, 2018
  • تاریخ انتشار: 1397/09/10
  • تعداد عناوین: 6
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  • Zahra Heydari * Pages 550-557
    In this article,the dissolution of Boric acid in different temperature conditions, with density functional theory (DFT) is studied. the Boric acid with chemical formula H3BO3 (sometimes written B(OH)3), and exists in the form of colorless crystals or a white powder that dissolves in water and produces Tetra hydroxy borate with the chemical formula [B(OH)4]− in different conditions of temperature, with density functional theory method were studied. For this purpose, at first the material contained in the both sides of reaction were geometrically optimized, and then the calculation of the thermodynamic parameters performed on all of them. The amount of ∆H, ∆S and ∆G of this reaction at different temperatures in form of sum of parameters discrepancy in the products than reactants is obtained. And finally, the best temperature for the synthesis of explosiveaccording to the obtained thermodynamic parameters were evaluated.
    Keywords: Boric acid, dissolves, Tetra hydroxyl borate, Density Functional Theory
  • Mahnaz Sadat Zolfaghari * Pages 558-569
    The project is comparing two types of calculation derived graphene. Which one of these carbon graphene linked to the phenylalanine amino acid from the acidic site (-COOH) and another from the base site (-NH2). For this purpose, at first the material contained in the both sides of reaction were geometrically optimized, then the calculation of the thermodynamic parameters performed on all of them. The amount of ∆H, ∆S and ∆G of this reaction at different temperatures in form of sum of parameters discrepancy in the products than reactants are obtained, and finally, the best temperature for the synthesis of derivations of phenylalanine - Graphene according to the obtained thermodynamic parameters were evaluated.
    Keywords: phenylalanine amino acid, Graphene, base & acid binding position, density functional theory
  • Masoud Mohammadi Zeydi *, Masoumeh Sedighi Gildeh Pages 570-583
    In this work, γ-Fe2O3@KSF as a stable heterogeneous and magnetic catalyst was prepared by the successive coating of γ-Fe2O3 shell on KSF core. The prepared reagent was characterized using different methods including FT-IR, XRD, TGA and SEM techniques and used for the one-pot synthesis of pyrano-pyrimidinone derivatives. All reactions were performed under mild conditions, during short reaction times in high yields. The catalyst could be easily recovered by an external magnet and reused several times without any considerable loss of its activity.
    Keywords: ?-Fe2O3@KSF, heterogeneous, magnetic, pyrano-pyrimidinone
  • golrokh Mahmoudzadeh *, Saeed Abedini Khorrami Pages 584-592
    Nanocomposite zinc ferrites were synthesized using glycine-nitrates by sol–gel auto-combustion technique. The influence of calcination temperatures varying from 400 to 900°C on structural and magnetic properties of spinel ZnFe2O4 powders have been investigated. The characterization measurements including X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were performed for as-synthesized zinc ferrite particles. In brief, the effect of calcination temperature on magnetic behavior, demonstrated that, the magnitude saturation magnetization (Ms) and remnant magnetization (Mr) were decreased with the increasing temperature for synthesized samples. In turn, the coercivity (Hc) and the shape of the hysteresis curve are affected significantly by calcination temperature. The coercivity (Hc) is closely related to the microstructure, particle/grain size, shape of the pores of the crystals, and many other complex factors. The calcined sample at 400°C has the best magnetic properties with the highest Ms of 16. 24 emug-1, and with Hc of 102.79Oe (at 10 kOe).
    Keywords: Nanocomposite, ZnFe2O4, Calcination Temperature, Characterization, Magnetic Properties
  • Alagappan Subramaniyan *, Elshadi Hegin, Jai Shalini Pages 593-599
    Nanocomposites have improved aspect ratio and better mechanical properties when compared to the composites which had structures less than 100nm They are 1000 times tougher compared to conventional composites. Besides mechanical properties, nanocomposites also have improved electrical conductivity, thermal stability, chemically resistant, flame retardant and low permeability. TiO2 finds its best application in the field of photo catalytic activity and it is used in sunscreen lotions since it is resistant to UVA(315-400nm) and UVB(280-315nm). Fe2O3 is used as the pigment in construction of roof tiles, pavers, plaster etc. It is used as a polishing agent for glass, diamonds and it is dental abrasive. It is reported that a nanocomposites of TiO2- Fe2O3 have improved visible water light splitting, and photocatalytic degradation of pollutants.The acute toxicity of the oxide nanoparticles make them suitable for their applications.The objective of the present work is to synthesize composites of titanium dioxide -iron oxide by a simple sol gel route in laboratory scale and to validate them as nanoparticles for preparation of nanofluids.
    Keywords: Sol gel, TiO2, Fe2O3, Nanocomposite
  • Aram Ghaempanah, Darioush Sharafie* Pages 600-609
    Clusters play important role for understanding and transferring microscopic to macroscopic properties.Geometric and electron properties of Small nickel clusters up to the tetramer has been investigated by Density Functional Theory (DFT). Raising the number of nickel clusters atoms were indicated decreasing the average equilibrium (Ni-Ni) distance of atoms and also the binding energy of per atom were showed increasing trend. Ni-Ni binding energy diagram shows a linear behavior in terms of (n-1/3). It is correspond with the previous findings. During the process HOMO-LUMO gap energies reduce. The lowest HOMO-LUMO gap energy was related to Ni8 cluster, so it proves that the cluster is more reactive and less kinetic stability. The linear relationship between size of clusters (n-1/3) with some properties of clusters indicate that it can get these properties (X∞) and extrapolated to the mass of the material.
    Keywords: Ni nanocluster, DFT, Electronic properties, HOMO-LUMO gap, Binding energy