Inhibiting effects of 4-amino-antipyrine based schiff base derivatives on the corrosion of mild steel in hydrochloric acid

The inhibiting action of 4-amino-antipyrine (AAP) and its schiff bases 4-[(benzylidene)-amino]-antipyrine (BAAP), 4-[(4-hydroxy benzylidene)-amino]-antipyrine (SAAP) and 4-[(4-methoxy benzylidene)-amino]-antipyrine (AAAP) which are derived from 4-amino-antipyrine with benzaldehyde, salicylaldehyde and anisaldehyde, toward the corrosion behavior of mild steel in 1 M HCl solution was studied using weight loss, potentiodynamic polarization, electrochemical impedance and FT-IR spectroscopic techniques. Although AAP was found to retard the corrosion rate of mild steel, the synthesized schiff base compounds were seen to retard the corrosion rate very effectively. The inhibitor efficiencies calculated from all the applied methods were in good agreement and were found to be in the order: AAAP > SAAP > BAAP > AAP.