Abstract
•Four ionic liquids have been investigated as corrosion inhibitors in acidic solution.•The new ionic liquids are potent mixed corrosion inhibitors.•Langmuir model accurately defined their adsorption on a steel substrate.•Ionic liquid inhibition effectiveness increases with the rising temperature.•NO2 group has a negative effect on the adsorption of ionic liquid molecules.
The inhibitory mechanism of four ionic liquids (ILs) generated from imidazolium is reported in this study. The goal of the research was to see how the cation structure of ILs affected the corrosion inhibition of carbon steel in 1 M HCl. The chemical structure of ILs was verified by elements analysis, Fourier-transform-infrared (FTIR), thermo gravimetric (TGA), nuclearmagnetic resonance (1HNMR, D2O, 13C NMR) and hetero-nuclear single-quantum correlation (HSQC). The inhibitory efficiency was measured using mass loss and electrochemical tests and varied from 62.5% to 97.2%. The Langmuir model accurately defined their adsorption on a steel substrate. Adsorption of novel ILs on steel substrates is a mixed physisorption and chemisorption method. To ensure the mechanism of adsorption of current ionic liquids, FTIR and ultraviolet (UV) spectra were employed.