Synthesis and Biological Evaluation of Novel Thiophene Derivatives as Green Inhibitors for Aluminum Corrosion in Acidic Media

Abstract—The corrosion behavior of Al in 1 M HCl solution with and without thiophene derivatives is studied utilizing altered chemical and electrochemical methods. Thiophene derivatives have been prepared and characterized by infrared (IR), proton nuclear magnetic resonance (¹H NMR) and mass spectral studies. The corrosion data were obtained using weight reduction and electrochemical techniques. The outcome data revealed that the efficiency rises with improving the dose of thiophene derivatives in aggressive solution, while it lowered with the rise of temperature. The adsorption of the studied thiophene derivatives on the surface of Al follows Langmuir isotherm. The thermodynamic parameters such as adsorption constant K_ads and free energy of adsorption ($\Delta G_{{{\text{ads}}}}^{^\circ }$) are calculated and discussed. Polarization curves indicated that the thiophene derivatives are mixed-kind inhibitors. The quantum calculation such as E_HOMO, E_LUMO and ΔE were obtained and related to the experimental data. The biological effect of these derivatives also discussed.