Ultrasound-Assisted Synthesis of 2‑Benzylidene-1-Indanone Derivatives and Evaluation as a Corrosion Inhibitor for Mild Steel in 1 M HCl Solution

This study explores the ultrasound-assisted synthesis of three 2-benzylidene-1-indanone derivatives and assesses their effectiveness as corrosion inhibitors for mild steel AISI 1018 in 1 M HCl through electrochemical techniques and density functional theory (DFT) quantum chemical calculations. The results indicate that the inhibitors studied; specifically IND-1, (Z)-2-(hydroxy-(phenyl)-methylene)-2,3-dihydro-1H-inden-1-one; IND-2, (Z)-2-(hydroxy-(pyridine-3-yl)-methylene)-2,3-dihydro-1H-inden-1-one and IND-3, (Z)-2-((4-(dimethylamino)-phenyl)-(hydroxy)-methylene)-2,3-dihydro-1H-inden-1-one, modified the cathodic reaction mechanism. These inhibitors achieve efficiencies greater than 98%, and their inhibitory effect does not increase with higher concentrations. A comparison of computational predictions and experimental analyses indicates that the pyridine ring and the diethylamino group reduce the inhibitory capacity of carbon steel in acidic environments.