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Flora X.H.,Alagappa University | Flora X.H.,Kamaraj College | Ulaganathan M.,Nanyang Technological University | Rajendran S.,Alagappa University
International Journal of Polymeric Materials and Polymeric Biomaterials | Year: 2013

In this work, polymer electrolytes composed of PAN/PMMA/LiClO4 with different plasticizers are prepared using solvent casting technique. Ionic conductivity of the electrolytes is evaluated with the help of ac impedance study at various temperatures. Structural and the complexation of the prepared electrolytes are studied by XRD and FTIR analysis, respectively. Thermogravimetric/differential thermal analysis (TG/DTA) is used to find the thermal stability of the polymer electrolytes. PAN/PMMA/EC/LiClO 4-based plasticized polymer electrolyte is found to possess optimal properties in terms of conductivity and thermal stability. Porous nature of the polymer gel electrolytes is also confirmed by SEM analysis. © 2013 Copyright Taylor and Francis Group, LLC. Source

Kanagaprabha S.,Kamaraj College | Asvinimeenaatci A.T.,Nmssvn College | Rajeswarapalanichamy R.,Nmssvn College | Iyakutti K.,Madurai Kamaraj University
Physica B: Condensed Matter | Year: 2012

First principles calculation were performed using Vienna ab-initio simulation package within the frame work of density functional theory (DFT) to understand the electronic properties of magnesium hydride. At normal pressure, the most stable structure of MgH2 is rutile type with a wide band gap of 3.52 eV, which agrees well with the available data. A pressure induced semi-conductor to metallic transition at a pressure of 92.54 GPa is predicted. Our results indicate a sequence of pressure induced structural phase transition in MgH2. The obtained sequence of phase transition was α→γ→β→δ→ε at a pressure of 0.37 GPa, 3.89 GPa,7.23 GPa and 11.26 GPa, respectively. Thus our results indicate that MgH2 is one of the best hydrogen storage material and the maximum storage capacity achieved was 7.7%. © 2011 Elsevier B.V. All rights reserved. Source

Sugirtha Devi S.,Kamaraj College
Journal of Molecular Catalysis A: Chemical | Year: 2014

Oxidative decarboxylation of phenylsulfinylacetic acid (PSAA) and several substituted PSAAs with three oxo(salen)chromium(V) complexes in the presence of nitrogen bases are investigated in 100% acetonitrile medium using spectrophotometric technique. The nitrogenous bases such as imidazole, 1-methyl imidazole and pyridine catalyse the reaction and Michaelis-Menten kinetics is observed with respect to these bases. Among the various bases employed, imidazole with strong π donating ability shows the least accelerating effect and the maximum catalytic activity is observed with pyridine. Both the electron donating and electron withdrawing substituents in PSAA accelerate the reaction rate. The Hammett plots for the three oxo(salen)chromium(V) complexes with three nitrogen bases display a nonlinear upward curvature. The Hammett parameter ρ, changes from large negative to small positive values as the substituents are changed from electron donating to electron withdrawing groups. A mechanism involving direct oxygen transfer from oxo(salen)chromium(V)-nitrogen base adduct to PSAA with simultaneous decarboxylation to yield sulfone is proposed. The nonlinear Hammett plot has been ascribed to a shift in the rate determining step caused by the formation and decomposition of the sulfonium ion intermediate which is susceptible to substituent effect. © 2014 Elsevier B.V. Source

Selvi N.T.,Govindammal Aditanar College for Women | Devi S.S.,Kamaraj College
Journal of the Korean Chemical Society | Year: 2014

The oxidative decarboxylation of phenylsulfinylacetic acid (PSAA) by Cr(VI) in 20% acetonitrile - 80% water (v/v) medium follows overall second order kinetics, first order each with respect to [PSAA] and [Cr(VI)] at constant [H+] and ionic strength. The reaction is acid catalysed, the order with respect to [H+] is unity and the active oxidizing species is found to be HCrO3 +. The reaction mechanism involves the rate determining nucleophilic attack of sulfur atom of PSAA on chromium of HCrO3 + forming a sulfonium ion intermediate. The intermediate then undergoes a,β-cleavage leading to the liberation of CO2. The product of the reaction is found to be methyl phenyl sulfone. The operation of substituent effect shows that PSAA containing electron-releasing groups in the meta- and para-positions accelerate the reaction rate while electron withdrawing groups retard the rate. An excellent correlation is found to exist between log k2 and Hammett s constants with a negative value of reaction constant. The p value decreases with increase in temperature evidencing the high reactivity and low selectivity in the case of substituted PSAAs. Source

Veni T.,Kamaraj College | Pushpanathan T.,St Xaviers College Autonomous
Asian Journal of Pharmaceutical and Clinical Research | Year: 2014

Objective: The objective of the study was to evaluate antibacterial potential and phytochemical analysis of various extracts of Argemone Mexicana. Methods: The antimicrobial activity of various extracts of A. Mexicana were analysed by using agar well disc diffusion method. Results: The ethanolic and methanolic extracst of A. mexicana had showed significant antimicrobial activity. Similar result was not observed in other four extracts. The higher content of reducing sugar, flavanoids, tannin, sterol, terpene and alkaloid were found in all the extracts of A. Mexicana are comparable with Amoxicillin. Conclusion: The results obtained from this study indicate that A. mexicana is a potential source of antimicrobial and thus could prevent many diseases. Source

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