Mitigation of mild steel corrosion using Schiff base-derived inhibitors in acidic media: An experimental and theoretical study

Abstract

Corrosion presents a substantial hurdle in the oil and gas industry, and corrosion inhibitors represent an economically viable strategy for control and prevention. As operating conditions in oil and gas extraction become increasingly harsh, factors such as cost, availability, and service temperature significantly influence inhibitor selection. While there is a wealth of literature on organic corrosion inhibitors, many exhibit a notable decrease in effectiveness at elevated temperatures, hindering their industrial application. To address this issue, we synthesized a novel Schiff base derivative, 1-((E)-(4-chlorophenylimino)methyl)naphthalen-2-ol (E4CMN), and investigated its effectiveness in inhibiting corrosion on Q235 immersed in a 1 M HCl. E4CMN adsorbs onto the surface by forming strong π-d interactions with Fe through the delocalized π electrons in its conjugated structure, effectively blocking the attack of corrosive particles towards the metal surface and consequently suppressing metal corrosion. Our study demonstrates that E4CMN exhibits maximum efficiencies of 96.9 % at a concentration of 250 mg L⁻¹. Importantly, E4CMN shows insensitivity to service temperature, maintaining an 84.4 % corrosion inhibition efficiency even when exposed to 75 °C. This work provides novel insights into mechanism of inhibition of mild steel corrosion by Schiff base derivatives in acidic environments and offers valuable considerations for the development and selection of corrosion inhibitors for high-temperature applications.