Experimental and Theoretical Study on Gemini‐Mannich Base as a Highly Effective Corrosion Inhibitor in Oilfield Acidification

ABSTRACT Although Mannich base corrosion inhibitors have been extensively studied, the role of a single functional group in enhancing corrosion inhibition efficiency remains limited. Numerous studies have confirmed that the combination of functional groups, or dual functionalization, can significantly improve this efficiency. This paper reports a novel Gemini‐Mannich base corrosion inhibitor (BEFC) synthesized from ethanolamine, formaldehyde, and cyclohexanone. This inhibitor significantly reduced the adsorption equilibrium concentration on the steel plate surface in hydrochloric acid solution, thereby substantially improving corrosion inhibition efficiency. In a 5% HCl solution at 343 K, BEFC exhibited significantly better corrosion inhibition performance at its maximum concentration compared to other inhibitors of the same type. Electrochemical experiments further revealed that BEFC acts primarily as a cathodic corrosion inhibitor, mainly suppressing the cathodic hydrogen evolution reaction. Quantum chemical calculations and molecular dynamics simulations supported these findings, indicating that BEFC molecules adsorb parallel to the metal substrate based on a conjugated plane.This adsorption mechanism enhances the overall corrosion inhibition performance of BEFC. The economic evaluation results show that the BEFC has obvious commercial competitive advantages and therefore has a very optimistic application prospect.