Browsing by Author "Shekara, P."

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    Experimental and Theoretical Approach for the Corrosion Deceleration of Mild Steel in Hydrochloric Acid Medium by Two Sulfonamide Derivatives
    (John Wiley and Sons Inc, 2024) D’Souza, P.R.; Kudva, J.; Kumar, A.S.; Shekara, P.; Naral, D.; Nityananda Shetty, A.N.
    In the pursuit to find corrosion inhibitors of superior efficacy, N-(pyrimidin-2-yl)-4-[(quinazoline-4-yl)amino]benzene-1-sulfonamide (PQS) and N-(4-methylpyrimidin-2-yl)-4-[(quinazoline-4-yl)amino]benzene-1-sulfonamide (MQS) are the two new sulfonamides employed, which have decelerating effect on mild steel (MS) corrosion in a medium 0.5 M HCl and were found to have an efficiency of 98.7 % and 96.8 % respectively (303 K for 40 ppm concentration) deliberated through the electrochemical techniques (PDP and EIS). The inhibitory efficacy relies on the temperature of the solution and inhibitor concentration. PQS had greater stability than MQS at higher temperatures which is indicative in the obtained experimental data. The relative adsorption process was in consonance with the Langmuir adsorption isotherm. The SEM, EDS, FT-IR, and AFM analysis validated PQS and MQS to form a barrier on MS, opposing corrosion. The potential energy surfaces (PES) scan and a theoretical study for PQS and MQS were probed employing density functional theory (DFT) at B3LYP/6-311+G(d, p) basis set level that explicated the formation of a complex between the sulfonamides and MS. The corrosion inhibition efficiency of PQS and MQS inferred from experimental and theoretical data comply, making them credible corrosion inhibitors. © 2024 Wiley-VCH GmbH.
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    Pyrazoline Derivative as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium: Experimental and Theoretical Approach
    (John Wiley and Sons Inc, 2023) Shekara, P.; Kudva, J.; Sadashiva, R.; Naral, D.; D’Souza, P.R.; Shetty, N.A.
    A new pyrazoline derivative, 1-[5-(4-bromophenyl)-3-(6-methoxypyridine-3-yl)-4-5-dihydro-1H-pyrazol-1-yl]-ethane-1-one (BMDP) was synthesised using chalcone derivative. The FTIR, 1HNMR, and mass spectral analysis were performed to validate the synthesised compound. The electrochemical impedance spectroscopy and potentiodynamic polarization techniques were performed to evaluate BMDP as a corrosion inhibitor for mild steel. The corrosion inhibition was observed to rise with an increase in BMDP concentration and decline with an increase in temperature. The maximum inhibition efficiency of 91.1 % was reported at 303 K in 40 ppm of BMDP concentration. Activation and adsorption parameters were found with statistical thermodynamic calculations. The surface investigation of the metal surface was performed by SEM, AFM and EDX techniques. UV-visible spectroscopy was used to realise the inhibitor-metal complex formation. The quantum chemical computations were performed by density functional theory using Gaussian 16 software, and the theoretical calculations confirm the outstanding anticorrosive property of BMDP at the diminutive level as analysed in electrochemical studies. © 2023 Wiley-VCH GmbH.