Electrochemical and Theoretical Study of Corrosion Inhibition on Carbon Steel in 1M HCl Medium by 1,10-Bis(4-Amino-3-Methyl-1,2,4-Triazole-5-Thioyl)Decane

Abstract

Corrosion inhibition using bolaamphiphile surfactants is related to the ability of these compounds to adsorb on liquid–solid interface. In this work, we have synthesized the 1,10-bis(4-amino-3-methyl-1,2,4-triazole-5-thioyl)decane (DTC10) using a new method developed in our laboratory. The synthesized compounds have been purified and characterized by NMR1H and NMR13C spectroscopy. The inhibiting action of DTC10 toward the corrosion of carbon steel in HCl1M solution was investigated using potentiodynamic and electrochemical impedance spectroscopy. We have shown that this compound acts as very good inhibitor for carbon steel in 1M HCl. The values of the transfer resistance, obtained from impedance plots of carbon steel, increase by increasing inhibitor concentration and reach 92% for 10−3M of DTC10. The effects of temperature and immersion time on the inhibition efficiency have also been studied. The effect of temperature was studied between 298 and 328 K; the activation energy Ea and other thermodynamic parameters were calculated. Donating and anti-donating properties of the studied inhibitor 1,10-bis(4-amino-3-methyl-1,2,4-triazole-5-thioyl)decane (DTC10) were illustrated using nucleophilic P− and electrophilic P+ Parr functions based on the density functional theory (DFT). The computational Monte Carlo (MC) method was performed to study the adsorption behavior of DTC10 onto Fe(111) surface in the solution (presence of H3O+, Cl− and H2O particles) and in the vacuum (absence of H3O+, Cl− and H2O particles). Accordingly, the adsorption of DTC10 on the iron surface (111) is more preferred in the solution than in the vacuum.