Adsorption and theoretical investigation of a novel bipyrazolic compound's ability to suppress corrosion on mild steel in a 1 M HCl solution

Abstract

This research investigates the synthesis and characterization of 1,6-bis(1-(chloromethyl)-5-methyl-1H-pyrazol-3-yl)hexane (Pyr1) and its role in inhibiting mild steel corrosion. Diverse corrosion evaluation methods, such as weight loss analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), were employed to assess the corrosion inhibiting properties of this bipyrazolic compound. Experimental outcomes reveal its efficacy as a corrosion inhibitor, demonstrating increased inhibition efficiency with higher inhibitor concentrations (91.14 % at 10⁻³ M). Moreover, the compound's adsorption behavior on the mild steel surface conforms to the Langmuir isotherm. The negative result of ΔG_ads suggests that bipyrazolic molecules spontaneously adsorb onto the mild steel surface. To establish a connection between experimental findings and theoretical aspects, the compounds' reactivity was studied using quantum chemistry and density functional theory (DFT). This analysis elucidates the compound's effectiveness as a corrosion inhibitor and offers insights into the mechanism behind corrosion inhibition. Overall, this study contributes to comprehending the potential of 1,6-Bis(3′-chloromethyl-5′-methyl-l ‘-pyrazolyl)hexane as a mild steel corrosion inhibitor by merging experimental observations with theoretical insights.