4-Aminoantipyrine Schiff base derivatives as novel corrosion inhibitors for Q235 steel in hydrochloric acid medium

The inhibitive effect of newly synthesized 4-aminoantipyrine Schiff base derivatives (1-3) against Q235 steel and its adsorption behavior were investigated in 2 M HCl solution using weight-loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The results showed that the inhibition efficiency increased with the increase of the inhibitor concentration. The 4-aminoantipyrine Schiff base derivatives are a mixed-type inhibitor whose adsorption behavior onto Q235 steel can be well fitted by Temkin isotherm equation. The quantum chemistry was used to gain some insight, about structural and electronic effects in relation to the inhibiting efficiencies. EIS spectra exhibit one capacitive loop and confirm the inhibitive ability. X-ray diffraction patterns (XRD) for both compounds (1 and 2) show polycrystalline nature and compound (3) shows a mixture of amorphous and polycrystalline nature. Molecular docking was used to predict the binding between 4-aminoantipyrine Schiff base derivatives with the receptor of 3hb5- oxidoreductase receptor of breast