Corrosion inhibition efficacy of quinazolinone quaternary ammonium on L245N in CO2-saturated brine (5 Wt.% NaCl): synthesis, experiments and theoretical studies

Purpose This study aims to evaluate the efficacy of a newly synthesized quinazolinone-quaternary ammonium derivative (BIQ) as a corrosion inhibitor for L245N steel in CO2-saturated brine. Design/methodology/approach BIQ was synthesized and tested using gravimetric analysis, electrochemical measurements (electrochemical impedance spectroscopy, potentiodynamic polarization) and surface characterization (Scanning electron microscopy, X-ray photoelectron spectroscopy) in 5 Wt.% NaCl solution. Quantum chemical calculations and molecular dynamics simulations were used to elucidate the adsorption mechanism. Findings BIQ demonstrated high inhibition efficiency (up to 95.2%), reducing the corrosion rate from 0.700 to 0.034 mm/a. It forms a dense protective film via parallel adsorption, confirmed by surface analysis and theoretical models showing strong electrostatic and chemical interactions. Originality/value The study introduces a novel hybrid inhibitor combining quinazolinone and quaternary ammonium moieties, revealing a dual-action protection mechanism driven by p-electron donation and electrostatic anchoring.