Correlated DFT and electrochemical study on inhibition behavior of ethyl 6-amino-5-cyano-2-methyl-4-(p-tolyl)-4H-pyran-3-carboxylate for the corrosion of mild steel in HCl

Abstract

The inhibition effect of ethyl 6-amino-5-cyano-2-me thyl-4-(p-tolyl)-4H-pyran-3-carboxylate (Pyr2) on t he corrosion of mild steel in 1.0 M HCl was investigated by ele ctrochemical (potentiodynamic polarization and elec trochemical impedance spectroscopic studies) and theoretical me thods. The potentiodynamic polarization was carried at different temperatures ranging from 298 to 328 K. I n all the studies, Inhibition efficiency increases with increase in concentrations of Pyr2 but decreases with rise in t he temperature. Potentiodynamic polarization measur ements confirmed that the inhibitive action of this compou nd is of mixed type. The activation parameters and thermodynamic values responsible for the adsorption were discussed. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isother m. Density functional theory (DFT) at the B3LYP/6-3 11G(d,p) basis set level was performed. Excellent correlatio n was found between experimental and theoretical re sults.