Browsing by Author "Naral, D."

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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.
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.
Synthesis, Characterization, Thermal and Antimicrobial studies of N-substituted Sulfanilamide derivatives
(2014) Lahtinen, M.; Kudva, J.; Hegde, P.; Bhat, K.; Kolehmainen, E.; Nonappa; Venkatesh; Naral, D.
Four sulfanilamide derivatives N-[4-(phenylsulfamoyl)phenyl]acetamide (1), 4-amino-N-phenylbenzenesulfonamide (2), N-[4-(phenylsulfamoyl)phenyl]benzamide (3) and N-{4-[(3-chlorophenyl)sulfamoyl]phenylbenzamide (4) were synthesized and characterized by Infra-Red (IR), Nuclear Magnetic Resonance (NMR) and UV-visible (UV-Vis) spectra. Also Liquid Chromatographic (LCMS) and High Resolution Mass Spectrometric (HRMS) methods were used. Crystal structures of 1-4 were determined by single crystal X-ray diffraction (XRD) and their conformational and hydrogen bond (HB) network properties were examined with survey of the literature data. Compounds 1 and 2 crystallize in the same orthorhombic Pbca symmetry with equivalent molecular conformation (tilted V-shape) but showed distinct packing and hydrogen bonding models. Compounds 3 and 4 crystallize in monoclinic and triclinic crystal systems, albeit exhibiting identical molecular conformation (L-shaped). Same donor acceptor pairs both on 3 and 4 result to different kind of HB network. Thermogravimetric (TG) and differential scanning calorimetric (DSC) methods were used to evaluate thermal properties of the substances. All sulfanilamide derivatives have melting points between195-227 C, initiation of thermal decomposition between 259-271 C and enthalpies of fusion ?HfusT = 38.96, 36.60, 46.23 and 44.81 kJ mol -1 were determined for 1-4, respectively. The derivatives were screened for their antibacterial and antifungal activities against various bacterial and fungal strains. It is observed that there is no significant antibacterial activity with the introduction of the benzene ring to CO-NH group or SO2-NH moiety, and none of the compounds exhibited antifungal activity. 2013 Elsevier B.V. All rights reserved.
Synthesis, Characterization, Thermal and Antimicrobial studies of N-substituted Sulfanilamide derivatives
(2014) Lahtinen, M.; Kudva, J.; Hegde, P.; Bhat, K.; Kolehmainen, E.; Nonappa, N.; Venkatesh; Naral, D.
Four sulfanilamide derivatives N-[4-(phenylsulfamoyl)phenyl]acetamide (1), 4-amino-N-phenylbenzenesulfonamide (2), N-[4-(phenylsulfamoyl)phenyl]benzamide (3) and N-{4-[(3-chlorophenyl)sulfamoyl]phenylbenzamide (4) were synthesized and characterized by Infra-Red (IR), Nuclear Magnetic Resonance (NMR) and UV-visible (UV-Vis) spectra. Also Liquid Chromatographic (LCMS) and High Resolution Mass Spectrometric (HRMS) methods were used. Crystal structures of 1-4 were determined by single crystal X-ray diffraction (XRD) and their conformational and hydrogen bond (HB) network properties were examined with survey of the literature data. Compounds 1 and 2 crystallize in the same orthorhombic Pbca symmetry with equivalent molecular conformation (tilted V-shape) but showed distinct packing and hydrogen bonding models. Compounds 3 and 4 crystallize in monoclinic and triclinic crystal systems, albeit exhibiting identical molecular conformation (L-shaped). Same donor acceptor pairs both on 3 and 4 result to different kind of HB network. Thermogravimetric (TG) and differential scanning calorimetric (DSC) methods were used to evaluate thermal properties of the substances. All sulfanilamide derivatives have melting points between195-227 C, initiation of thermal decomposition between 259-271 C and enthalpies of fusion ?HfusT = 38.96, 36.60, 46.23 and 44.81 kJ mol -1 were determined for 1-4, respectively. The derivatives were screened for their antibacterial and antifungal activities against various bacterial and fungal strains. It is observed that there is no significant antibacterial activity with the introduction of the benzene ring to CO-NH group or SO2-NH moiety, and none of the compounds exhibited antifungal activity. © 2013 Elsevier B.V. All rights reserved.