Enhanced corrosion resistance of mild steel in 1 M HCl solution by trace amount of 2-phenyl-benzothiazole derivatives: Experimental, quantum chemical calculations and molecular dynamics (MD) simulation studies

The inhibition performance of 2-(2'-hydroxylphenyl)benzothiazole, (1), 2-(2',5'-dihydroxyphenyl)benzothiazole, (2), and (4-benzothiazole-2-yl-phenyl)-dimethyl-amine, (3), has been investigated for mild steel in 1 M HCI. Notably, compound 3 shows 95% inhibition efficiency at 50 ppm (by weight) concentration. The adsorption of these compounds obeys the Langmuir adsorption isotherm with predominately chemisorption for 3 and comprehensive for 1 and 2. Quantum chemical calculations predicted an inhibition order of 3 > 2 > 1, is at odds with the experimental order due the structural effects. Molecular dynamic simulation revealed a nearly flat configuration for molecules on metal surface with negative binding energies in a sequence agreed by the experiments, 3 >1 >2. (C) 2016 Elsevier Ltd.All rights reserved.