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Tiruchirappalli, India

Kinetic investigation of oxidation of galactose and mannose, by alkaline solution of N-Bromonicotinamide (NBN) has been carried out in the temperature range 305-325K. The reaction shows first order in [alkali]. Both oxidations are of fractional order in [substrate] and inverse first order about oxidant. Addition of nicotinamide (NA) shows a retarding effect. Increase in ionic strength of the medium has no effect on the rate. Effect of temperature on the rate of oxidation has been followed to show the validity of Arrehenius equation and various activation parameters have been computed. The stoichiometry of the reaction was found to be 1:1. HOBr has been postulated as the reactive oxidizing species. The products of oxidation are the respective aldonic acids. Source


Krishnan C.,Arignar Anna College | Pari S.,National College
Current Applied Physics | Year: 2010

Single crystals of undoped (pure) and sodium chloride (NaCl)-doped Zinc Tris-thiourea Sulphate (ZTS) were grown from aqueous solutions by slow evaporation technique. Morphological alterations have been observed when NaCl is doped into ZTS crystals. Density of the grown crystals was measured by floatation method. The values of unit cell parameters from single crystal X-ray diffraction (XRD) studies show that pure and sodium chloride-doped ZTS crystals are in orthorhombic structure. Impurity concentration in the doped crystals was estimated by using an atomic absorption spectrometer. Second Harmonic Generation (SHG) test for the undoped and NaCl-doped ZTS crystals was performed by the powder technique of Kurtz and Perry using a pulsed Nd:YAG laser. Microhardness studies show that hardness number (Hv) increases with load for all the grown crystals of this work. From the values of work hardening coefficients, it is concluded that pure and sodium chloride-doped ZTS crystals belong to the category of soft materials. UV-vis-NIR spectra show that the grown crystals have wide optical transparency in the entire visible region. Birefringence studies of the grown samples have been performed by channelled spectrum method. The thermal stability of the materials is found to be increasing with the doping concentration of sodium chloride (NaCl) in the lattice of ZTS crystals. © 2009 Elsevier B.V. All rights reserved. Source


Arivazhagan M.,Aa Government Arts College | Jeyavijayan S.,Alagappa Chettiar College of Engineering And Technology | Geethapriya J.,National College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

The FTIR and FT-Raman spectra of 5-nitro-2-furaldehyde oxime (NFAO) have been recorded in the regions 4000-400 cm-1 and 3500-50 cm -1, respectively. The total energies of different conformations have been obtained from DFT (B3LYP) with 6-311++G(d,p) basis set calculations. The computational results identify the most stable conformer of NFAO as the C1 form. Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compound were carried out. The optimum molecular geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities, were calculated by density functional theory (DFT/B3LYP) method with 6-31+G(d,p) and 6-311++G(d,p) basis sets. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. A detailed interpretation of the infrared and Raman spectra of NFAO is also reported based on total energy distribution (TED). Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. Besides, molecular electrostatic potential (MEP), HOMO and LUMO analysis, and several thermodynamic properties were performed by the DFT method. Mulliken's net charges have been calculated and compared with the natural atomic charges. Ultraviolet-visible spectrum of the title molecule has also been calculated using TD-DFT method. © 2012 Elsevier B.V. All rights reserved. Source


Pushpalatha L.,National College
Oxidation Communications | Year: 2014

The kinetics of oxidation of methionine, an important, sulphur-containing essential amino acid, by N-chloronicotinamide (NCN) in the presence of 0.8 mol dm-3 HCl in aqueous acetic acid medium at constant ionic strength has been studied. The reaction shows fractional order with respect to substrate, inverse first order to oxidant and first order to hydrochloric acid. Addition of the reaction product, nicotinamide (NA), retarded the reaction. The rate increases with the increase in acetic acid proportion. Increase in temperature increases the rate. The activation parameters have been evaluated by studying the reaction at temperatures 300-325 K. The stoichiometry of the reaction was found to be 1:2. Molecular chlorine has been postulated as the reactive oxidising species. Methionine sulphoxide was the product. The product obtained was isolated and identified. Source


Pushpalatha L.,National College
Oxidation Communications | Year: 2014

Kinetic investigation of oxidation of glucose and fructose, by alkaline solution of N-chloronicotinamide (NCN) has been carried out in the temperature range 308-328 K. The reaction shows first order in [alkali] and [substrate] and zero order in oxidant. Addition of nicotinamide (NA) has no effect. Increase in ionic strength of the medium does not change the rate. Effect of temperature on the rate of oxidation has been followed to show the validity of the Arrhenius equation and various activation parameters have been computed. The stoichiometry of the reaction was found to be 1:1. 1,2-enediol is found to be the reactive intermediate. Gluconic acid and formic acid are the products of oxidation for glucose and fructose, respectively. Source

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