Quantum chemical and experimental investigations on equipotent effects of (+)R and (−)S enantiomers of racemic amisulpride as eco-friendly corrosion inhibitors for mild steel in acidic solution

The potential of amisulpride drug as a corrosion inhibitor for mild steel in 1 M HCl has thoroughly been investigated by electrochemical methods. Polarization curves showed that this compound has high inhibiting properties for steel corrosion in acidic solution and the inhibition efficiency increased with the increase in inhibitor concentration. The adsorption of the inhibitor on the surface of steel has been found to obey a Langmuir adsorption isotherm and the influence of temperature on the adsorption of inhibitors onto a mild steel surface has been reported. Quantum chemical computations at the density functional theory have been applied to study the inhibition performance of (+)R and (−)S enantiomers of racemic amisulpride. The quantitative structure-activity relationship (QSAR) approach has also been used to correlate the quantum chemical parameters with the experimentally determined inhibition efficiencies.