Synthetic, spectroscopic characterization, empirical and theoretical investigations on the corrosion inhibition characteristics of mild steel in molar hydrochloric acid by three novel 8-hydroxyquinoline derivatives

The newly synthesized quinoline derivatives were characterized using FTIR, NMR, and elemental analysis, and then they were evaluated as inhibitors against corrosion of mild steel (MS) in 1.0 M HCl. The corrosion testing and evaluation were performed thoroughly employing the weight loss method, electrochemical measurements, and surface analysis. We have demonstrated also that the 8-hydroxyquinoline derivatives react as mixed-type inhibitors. Experimental data show that the three inhibitors are effective against corrosion of steel in 1.0 M HCl and that the inhibitory efficiency reached at an optimum value of 96% for the Q-CH3 compound. In addition, the surface of the MS has been analyzed by SEM-EDS and the dissolution of steel in the gravimetric solution was analyzed by UV-visible spectrometry (UV-vis). The DFT calculations and Monte Carlo (MC) simulations were performed to understand the mechanism of inhibition of compounds with steel.