k) 2015 - 38 Documents
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Item THE INHIBITING EFFECT OF SOME QUINOXALINE DERIVATIVE TOWARDS MILD STEEL CORROSION IN ACID MEDIA: CHEMICAL, ELECTROCHEMICAL AND THEORETICAL STUDIES(Journal of Materials and Environmental Science, 2015) Saranya, J; Sounthari, P; Kiruthuka, A; Parameswari, K; Chitra, SCorrosion inhibition of mild steel in 1 M H2SO4 was investigated in the absence and presence of different concentrations of quinoxaline derivatives namely (3E)-3-(phenylimino)-3,4-dihydroquinoxalin-2(1H)-one (PDQO), (3E)-3-[(2-methylphenyl) imino]-3,4-dihydroquinoxalin-2(1H)-one (MPDQO) and (3E)-3-[(2-methoxy-phenyl)imino]-3,4-dihydroquinoxalin-2(1H)- one (MOPDQO). Weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were employed. Impedance measurements showed that the charge transfer resistance increased and double layer capacitance decreased with increase in the inhibitor concentration. Potentiodynamic polarization study showed that the inhibitors acted as mixed-type inhibitors. The adsorption of these compounds on the mild steel surface obeys a Langmuir adsorption isotherm. Results obtained reveal that compound MOPDQO is the best inhibitor and the inhibition efficiency follows the sequence: MOPDQO > MPDQO > PDQO. Electronic properties such as highest occupied molecular orbital (EHOMO) and lowest unoccupied molecular orbital (ELUMO), the energy difference (ΔE) between EHOMO and ELUMO, dipole moment (μ), electronegativity (χ), electron affinity (A), hardness (η), softness (σ), ionization potential (I), the fraction of electrons transferred (ΔN), total energy (TE) were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in the EHOMO values but decrease in the ELUMO values. Mulliken atomic charges, Fukui functions and softness indices were discussed in order to characterize the inhibition property of the inhibitorsItem SATIN LEAF (CHRYSOPHYLLUM OLIVIFORME) EXTRACT MEDIATED GREEN SYNTHESIS OF SILVER NANOPARTICLES: ANTIOXIDANT AND ANTICANCER ACTIVITIES(Journal of Pharmaceutical Sciences and Research, 2015) Anju Varghese, R; Anandhi, P; Arunadevi, R; Boovisha, A; Sounthari, P; Saranya, J; Parameswari, K; Chitra, SThe recent development and implementation of new technologies have led to new era, the nano-revolution which unfolds role of plants in bio and green synthesis of nanoparticles which seem to have drawn quite an unequivocal attention with a view of synthesizing stable nanoparticles. The biosynthesis of nanoparticles has been proposed as a cost effective and environmental friendly alternative to chemical and physical methods. Plant mediated synthesis of nanoparticles is a green chemistry approach that interconnects nanotechnology and plant biotechnology. In the present study, synthesis of silver nanoparticles (AgNPs) has been demonstrated using extracts of Chrysophyllum oliviforme reducing aqueous silver nitrate. The synthesized nanosilver was characterized by IR, UV, XRD and SEMEDS. The synthesized nano silver have been screened for antioxidant and anticancer activities.Item CORROSION INHIBITION EFFECT OF HYDROXY PYRAZOLINE DERIVATIVES ON MILD STEEL IN SULPHURIC ACID SOLUTION TOGETHER WITH QUANTUM CHEMICAL STUDIES(Journal of Materials and Environmental Science, 2015-03-13) Anusuya, N; Sounthari, P; Saranya, J; Parameswari, K; Chitra, SInhibition potential of synthesized pyrazoline derivatives on the corrosion inhibition of mild steel in 1M H2SO4 solution have been evaluated and studied by gravimetric, Tafel polarization, electrochemical impedance spectroscopy techniques and the quantum chemical studies using density functional theory (DFT). The results showed that the inhibition efficiency of the investigated compounds depend on the concentration and nature of the inhibitor. The effect of temperature on the corrosion behavior of mild steel in 1M H2SO4 without and with the inhibitors was studied in the temperature range 303 to 333 K. Some activated thermodynamic parameters were computed and discussed. Polarization studies showed that all the pyrazolines function as mixed inhibitor, but predominantly act as cathodic type. The surface morphology of inhibited mild steel was analyzed by scanning electron microscope technology with energy dispersive X-ray spectroscopy (SEM-EDX). FT-IR spectroscopic analysis was used to obtain information on bonding mechanism between the metallic surface and the inhibitors. Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), energy gap (∆E) and dipole moment (µ), the softness (σ), the fraction of the electrons transferred from the inhibitor to the metal surface (∆N) and the total energy (TE) have been calculated. It was found that theoretical data support the experimental results.Item ADSORPTION AND DENSITY FUNCTIONAL THEORY ON CORROSION OF MILD STEEL BY A QUINOXALINE DERIVATIVE(Scholars Research Library, 2015) Saranya, J; Sounthari, P; Parameswari, K; Chitra, S(3E)-3-{[4-(phenylsulfonyl)]imino}-3,4-dihydroquinoxalin-2(1H)-one (PSDQO) has been synthesized and its inhibiting action on the corrosion of mild steel in 1 M H2SO4 has been assessed by weight loss method at 303 K – 333 K. The results of the investigation show that this compound has excellent inhibiting properties for mild steel corrosion in sulphuric acid. Inhibition efficiency increases with increase in the concentration of the inhibitor. The adsorption of the inhibitor was tested for Langmuir, Temkin, Flory-Huggin’s and El-Awady isotherm and proved physical adsorption. Quantum chemical calculations were employed to give further insight into the mechanism of inhibitive action of the inhibitorItem QUANTUM CHEMICAL STUDY ON THE CORROSION INHIBITION PROPERTY OF SOME HETEROCYCLIC AZOLE DERIVATIVES(Oriental Journal of Chemistry, 2015-08-20) Anusuya, N; Sounthari, P; Saranya, J; Parameswari, K; Chitra, SQuantum chemical calculations based on density functional theory (DFT) method were performed on heterocyclic azole derivatives as corrosion inhibitors for mild steel in acid media to investigate the relationship between molecular structure of the inhibitors and the corresponding inhibition efficiencies (%). Quantum chemical parameters most relevant to their potential action as corrosion inhibitors have been calculated in the non-protonated and protonated forms in aqueous phase for comparison. Results obtained in this study indicate thatin acidic media, both the protonated and non-protonated forms of the azoles represent the better actual experimental situation.Item INHIBITION OF MILD STEEL CORROSION IN 1M H2SO4 MEDIUM BY BENZIMIDAZOLE MANNICH BASES(Oriental Journal of Chemistry, 2015-03-21) Dasami, P M; Parameswari, K; Chitra, SThe corrosion inhibition behaviour of two synthesized Mannich bases has been investigated for mild steel in 1M H2SO4 by weight loss and electrochemical techniques.The inhibition efficiency depends on concentration of the inhibitor and temperature. The inhibitors function by adsorption on mild steel surface and obey Langmuir isotherm indicating monolayer adsorption on the surface. Thermodynamic parameters show that the adsorption of the inhibitors occurs through electrostatic interaction. Polarization studies reveal that the inhibitors behave as mixed type in 1M H2SO4 affecting both anodic metal dissolution and cathodic hydrogen evolution. SEM studies show the formation of surface adsorptive film of the Mannich bases on the mild steel surface.Item SYNTHESIS, STRUCTURE, AND PHARMACOLOGICAL EVALUATION OF CO(III) COMPLEX CONTAINING TRIDENTATE SCHIFF BASE LIGAND(Springer Link, 2015-04-07) Jone Kirubavathy, S; Velmurugan, R; Karvembu, R; Bhuvanesh, N S P; Parameswari, K; Chitra, SA Co(III) Schiff base complex with the formula [Co(L)2]Cl · H2O (I) (L = monoanionic tridentate Schiff base ligand derived from salicylaldehyde and ethylene diamine) has been synthesized and characterized by elemental analysis and spectroscopic techniques. The structure of I was confirmed by single crystal X-ray diffraction studies (CIF file CCDC no. 1009967), which showed the presence of two Schiff base molecules in an octahedral fashion. The complex has been screened for its in vitro antibacterial and anticancer activities. Complex I was found to be more active in anti-microbial and anti-cancer activity than the ligand.Item CORROSION INHIBITION OF MILD STEEL IN 1MH2SO4 BY THIADIAZOLE SCHIFF BASES(Elsevier, 2015-06) Dasami, P M; Parameswari, K; Chitra, STwo novel Schiff bases derived from heterocyclic amines and aldehydes were synthesized and evaluated as corrosion inhibitors for mild steel in 1MH2SO4 by mass loss and electrochemical techniques. Inorder to understand the mechanism of inhibition, adsorption isotherms were tested. The studies showed that the inhibition efficiency depends on concentration of inhibitor and temperature of measurements. Electrochemical studies showed that the inhibitors behave as mixed type. Quantum chemical studies were used to substantiate the experimental results.