New imidazolium ionic liquids as ecofriendly corrosion inhibitors for mild steel in hydrochloric acid (1 M): Experimental and theoretical approach

The present paper was designed to investigate an original synthesized ionic liquid (ILs) named 1-phenethyl3-(3-phenoxypropyl)-1H-imidazol-3-ium bromide [Imid-3PE] Br, and 1-phenethyl-3-(4-phenoxybutyl)-1Himidazol-3-ium bromide [Imid-4PE] Br as corrosion inhibitors. These inhibitors were evaluated against mild steel corrosion in 1 M hydrochloric acid medium using electrochemical techniques. PDP experiments revealed that the [Imid-3PE] Br and [Imid-4PE] Br behaved as mixte type inhibitors. Electrochemical impedance spectroscopy (EIS) results indicated that the both compounds showed a good inhibition of the steel surface with an inhibition efficiency of 95.8% for [Imid-3PE] Br and 96.7% for [Imid-4PE] Br at the optimum concentration. According to Langmuir isotherm model and the activation parameters, these ILs can be adsorbed onto the mild steel surface through physical and chemical bonds. The theoretical approach confirms the adsorption behavior of the studied ILs based on DFT calculation and molecular dynamic simulation. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.