Abstract
The corrosion inhibition of mild steel in 3.2M H2SO4 solution by 1-benzyl piperazine (C2), 1,6-di(1-benzyl piperazine-1-carboxamide)hexane (C4), bis(1-benzyl piperazine) disulfure de thiuram (C5) inhibitors has been studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements and weight loss methods. Polarization studies clearly revealed that all the compounds used act as mixed-type inhibitors. The temperature on inhibitory behaviour of C2, C4 and C5 was investigated. Adsorption isotherms were fitted by Langmuir isotherm and adsorption energies (-G°ads) and kinetic parameters were evaluated. The correlation between inhibition efficiency and molecular structure of the compounds is investigated by determination of chemical indexes, which were performed using Gaussian03 package software, with density functional theory (DFT) and the correlation functional (B3LYP) in 6-31G* basis.