Effect of alkyl chain length and halide ions on the corrosion inhibition potential of imidazolium and pyridinium based ionic liquids: Computational studies

In the present investigation, thirty imidazolium and pyridinium based ionic liquids are undertaken for DFT based computational study to demonstrate the anticorrosive potential. Results showed that imidazolium and pyridinium based ionic liquids act as effective anticorrosive materials and their corrosion inhibition performance depends on the nature of alkyl groups and halide ions. Among the studied imidazolium based ionic liquids, 3-octyl-1H-imidazol-3-ium chloride (IM-C8-Cl), 3-hexadecyl-1H-imidazol-3-ium bromide (IM-C16-Br) and 3-butyl-1H-imidazol-3-ium iodide (IM-C4-I) behave as the best among the chloro, bromo and iodide substituted imidazolium based ionic liquids, respectively. In the pyridinium based ionic liquids, 1-hexadecylpyridin-1-ium chloride (Pyr-C16-Cl), 1-dodecylpyridin-1-ium bromide (Pyr-C12-Br) and 1-octylpyridin-1-ium iodide (Pyr-C8-I) act as the best corrosion inhibitors among the chloro, bromo and iodide substituted pyridinium based ionic liquids, respectively. Adsorption behavior of pyridinium and imidazolium based ionic liquids and corrosion inhibition using them has also been proposed in the present study.