Pyrazoline Derivative as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium: Experimental and Theoretical Approach.

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. [ABSTRACT FROM AUTHOR]