Corrosion inhibition of azomethine compounds for mild steel in 1M sulfuric acid/ Nurul Farhana Najib

Four schiff base compounds namely NO2sal-DET, NO2hap-DET, NO2salDMPDA and NO2hap-DMPDA were successfully synthesized and characterized by elemental analysis, Infrared and 1H NMR spectroscopy analysis as well as melting point determination. The inhibition effects of the schiff bases on the corrosion of mild steel in 1M H2SO4 were studied by weight loss method. Results showed that NO2sal-DET was the best inhibitor with efficiency of 84.21% at 1 x 10-2 M of inhibitor concentration. On the other hand, NO2hap-DMPDA was the least efficient inhibitor with efficiency of 66.67% at concentration of 1 x 10-2 M. The inhibition efficiency increased with increasing concentration of the schiff bases. The inhibitor performance seemed to be affected by the functional groups attached to the structure of the schiff bases. The methyl (CH3) group on the structure introduced steric hindrance that prevented the proper adsorption of the inhibitor on metal surfaces. As the amount of CH3 increased in the schiff base structure, the inhibition efficiency of the compound decreased