Investigation of substituents effect on the inhibitive properties of Schiff base compounds / Ahmad Shalabi Md. Sauri

A series of the acyclic Schiff base compounds, namely, N,N’-dibenzylideneethane-1,2-diamine (baen) and their methyl, hydroxyl and chloro derivatives were successfully synthesized. They were characterized using the elemental analyzer, Fourier transform infrared spectroscopy, ᶦH andᶦ³C nuclear magnetic resonance spectroscopy. The effectiveness of these compounds as the acidic corrosion inhibitor was measured using polarization, linear polarization resistance andelectro chemical impedance. The steel panels were used as the specimens. The data obtained indicate that the inhibition efficiency increases from 60.42% to80.76% in the presence of the substituents on the benzene rings. The presence of these substituents had facilitated the adsorption of the Schiff base molecules onto the steel surfaces through inductive and resonance effects. The adsorption behaviour of these molecules was well described based on Langmuir adsorption isotherm. The investigated Schiff base compounds were adsorbed uniformly as the protective monolayer through the physorption process.