Anticorrosion potential of some 5-amino-8-hydroxyquinolines derivatives on carbon steel in hydrochloric acid solution: Gravimetric, electrochemical, surface morphological, UV-visible, DFT and Monte Carlo simulations

In the present investigation, three 5-amino-8-hydroxyquinolines derivatives namely, 5-aminomethyl-8-hydroxyquinoline (AMHQ), 5-N-acethylaminomethyl-8-hydroxyquinoline (ACAMHQ), 5-N,N'- dimethylaminomethyl-8-hydroxyquinoline (DMHQ) were prepared and characterized by IR, H-1 NMR, C-13 NMR, Elemental analysis and Mass spectrometry. These three 5-amino-8-hydroxyquinolines derivatives were tested in the inhibition of corrosion of carbon steel (CS) in 1 M HCl using electrochemical impedance spectroscopy (EIS), Tafel polarization, weight loss, scanning electronic microscopy (SEM) and UV-visible spectroscopy. It was found that the inhibition efficiency of AMHQ ACAMHQ and DMHQ increased with increasing concentration. For the three organic compounds, the DMHQ shows better efficiency than the other two products reaches 97% at 10(-3) M concentration. Polarization studies showed that AMHQ ACAMHQ and DMHQ inhibitors were of mixed type in nature. The experimental data maked from EIS method show a frequency distribution and therefore a modeling element with frequency dispersion behavior, a constant phase element (CPE) has been utilized. To determine certain thermodynamic parameters of activation, the effect of temperature on corrosion rate was studied. The adsorption of 5-substituted-8-hydroxyquinolines derivatives on the carbon steel (CS) surface followed Langmuir adsorption isotherm. Scanning electron microscopy (SEM) and UV-visible spectroscopy were carried out on inhibited and uninhibited carbon steel samples to characterize the surface. Theoretical calculations were performed to gain further insight into the interaction of the inhibitors with carbon steel. (C) 2017 Elsevier B.V. All rights reserved.