Pyridazinium-based ionic liquids as novel and green corrosion inhibitors of carbon steel in acid medium: Electrochemical and molecular dynamics simulation studies

• Published in: Journal of molecular liquids Vol. 249; pp. 997 - 1008
• Main Authors: El-Hajjaji, F., Messali, M., Aljuhani, A., Aouad, M.R., Hammouti, B., Belghiti, M.E., Chauhan, D.S., Quraishi, M.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2018
• Subjects: Corrosion inhibitors; Electrochemical impedance spectroscopy; Ionic liquids; Molecular dynamics simulation; Ionic liquids; Corrosion inhibitors; Molecular dynamics simulation; Electrochemical impedance spectroscopy
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2017.11.111

Two new pyridazinium-based ionic liquids namely 1-(6-ethoxy-6-oxohexyl)pyridazin-1-ium bromide (S1) and 1-(2-bromoacetyl) pyridazinium bromide (S2) were synthesized and their inhibitive performance towards the corrosion of mild steel in 1M hydrochloric acid was studied using electrochemical impedance spectroscopy (EIS) at various temperatures (303–333K). It was shown that the inhibition efficiency increased with the concentration of S1 and S2 and reached 84% for S1 and 82% for S2 at 10−3M (303K). Impedance measurements revealed that the charge transfer resistance (Rct) increased and the double layer capacitance (Cdl) decreased with an increase in the concentration of both the inhibitors. The thermodynamic parameters provided the evidence of the inhibitory effect. Langmuir isotherm model fitted well with the adsorption of the studied compounds. Furthermore, spontaneity of the adsorption process, evaluated from the sign of free energy (ΔGadso) values, showed an increase upon increase in temperature in the presence of inhibitors. Dynamics simulation indicated the possibility of gradual substitution of water molecules from the iron surface.
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•Two new pyridazinium-based ionic liquids are used as corrosion inhibitors.•Detailed study on the effect of temperature and concentration using electrochemical impedance spectroscopy.•Influence of inhibitor concentration and temperature on relaxation frequency and relaxation time is investigated.•Inhibitors follow Langmuir adsorption isotherm and exhibit chemical adsorption.•Detailed study on molecular dynamics simulation is presented which supports experimental findings.