Chemical and Electrochemical Studies of Novel Quinazolinone Derivatives based on 8-hydroxyquinoline as Corrosion Inhibitor for Mild Steel in 1.0 M HCl Solution

Novel substituted quinazolinone derivatives based on 8-hydroxyquinoline were synthesized and identified by hydrogen-1 nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, and elemental analysis. The corrosion inhibition of these compounds in 1 M HCl Solution for mild steel was evaluated using potentiodynamic polarization measurements, electrochemical impedance spectroscopy, weight loss measurements. It is showed that these compounds are good inhibitors for mild steel corrosion in 1.0 M HCl solution which act as mixed type inhibitors. So, the inhibition efficiency was increased with inhibitor concentration in the order of QZn>QZ which depended on their molecular structures. Maximum values of inhibition efficiency 96% and 79% were obtained at low concentration (10-3 M) for QZn and QZ respectively. It is found also that the inhibition efficiency of these compounds slight decrease with temperature. In addition, the thermodynamic adsorption parameters at different concentrations were investigated and discussed. The both inhibitors as good acid corrosion inhibitors and were found to obey Langmuir adsorption isotherm. Additionally, the corrosion properties were also investigated by UV-visible spectrophotometry to obtain information on bonding mechanism between the metallic surface and the inhibitor. Scanning Electron Microscopy (SEM) was performed and discussed for surface study of uninhibited and inhibited mild steel samples.