Towards Understanding the Corrosion Inhibition Mechanism of Green Imidazolium-Based Ionic Liquids for Mild Steel Protection in Acidic Environments.

Two novel ecological ionic-liquid derivatives based on imidazolium (ILs), namely, 3-(2-ethoxy-2-oxoethyl)-1-phenethyl-1H-imidazol-3-ium-chloride [OE-IM+, Cl-] and 3-(4-ethoxy-4-oxobutyl)-1-phenethyl-1H-imidazol-3-ium-chloride [OB-IM+, Cl-] was studied by Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PP), SEM/EDX analysis and theoretical calculations. It is found that the studied ionic liquids exhibit high inhibition performance for Mild steel (MS) in 1 M HCl. Hence the formation of a barrier layer that retards redox reactions and therefore prevents the corrosion process of MS. Inhibition efficiency for all the compounds increases with their concentration and follows the order [OE-IM+, Cl-] < [OB-IM+, Cl-], indicating effective performance was achieved as the length of the alkyl chain attached to the imidazolium ring extended. Furthermore, DFT and MD simulations were used, revealing the impact of molecular configuration on the anticorrosive properties of these chemicals. [ABSTRACT FROM AUTHOR]