A green ultrasound-assisted access to some new 1-benzyl-3-(4-phenoxybutyl) imidazolium-based ionic liquids derivatives - potential corrosion inhibitors of mild steel in acidic environment

A green ultrasound-assisted synthesis and caracterization of two new ionic liquids derivatives namely,1-benzyl-3-(4-phenoxybutyl)-1h-imidazol-3-ium bromide (ma1) 1-benzyl-3-(4-phenoxybutyl)-1h-imidazol-3-ium tetrafluoroborate (ma2) is described and their inhibitive action against the corrosion of c-steel in 1.0 m hcl solution were investigated. the corrosion rate of steel decreased both in the presence of these two molecules. their inhibition efficiencies increase with the inhibitor concentration to reach 94.6 and 97.6% at 10-2 m of ma1 and ma2,respectively. the adsorption of thesecompounds on c-steel surface agrees langmuir's adsorption isotherm. the free enthalpy related to the adsorption processreveals the mode inhibitors adsorption. quantum chemical approach,using the density functional theory (dft),was applied in order to get better understanding about the relationship between the inhibition efficiency and molecular structure of ma1 and ma2. the calculated quantum chemical parameters include the highest occupied molecular orbital (homo),lowest unoccupied molecular orbital (lumo),dipole moment and amount of electrons transferred. the results of the study suggest that ma1 is a better corrosion inhibitor than ma2,which is in agreement with most experimental findings obtainedat different concentrations.