Experimental and theoretical investigation of 2-mercaptoquinoline-3-carbaldehyde and its Schiff base as an inhibitor of mild steel in 1 M HCl

•Corrosion inhibition efficacy of two quinoline derivatives is examined.•The inhibition efficiencies are highly satisfactory at concentrations of 25 ppm.•Obtained mixed type inhibitors obeying the Langmuir adsorption isotherm.•DFT calculated parameters are accord well with the experimental properties.•SEM measurements were applied to study the morphology of the MS surface.

Conventional weight loss, electrochemical measurements, quantum chemical calculations and scanning electron microscopy techniques were employed to investigate the inhibitive effects of two novel quinoline derivatives, 2-mercaptoquinoline-3-carbaldehyde and (Z)-3-((4-chlorophenylimino)methyl)quinoline-2-thiol on the corrosion of mild steel in 1 M HCl solutions. The decrease in the weight losses of mild steel samples has proved that both the additives were efficient inhibitors. The mixed mode of inhibition was confirmed by electrochemical polarizations. Both the inhibitors followed the Langmuir adsorption isotherm. In addition to this, the quantum chemical calculations were performed at B3LYP/6-31G(d,p) level to complement the experimental results.

Graphical abstractConventional weight loss, electrochemical measurements, quantum chemical calculations and scanning electron microscopy techniques were employed to investigate the inhibitive effects of two novel quinoline derivatives, 2-mercaptoquinoline-3-carbaldehyde and (Z)-3-((4-chlorophenylimino)methyl)quinoline-2-thiol on the corrosion of mild steel in 1 M HCl solutions.Figure optionsDownload full-size imageDownload as PowerPoint slide