Electrochemical and theoretical quantum approaches on the inhibition of mild steel corrosion in HCl using synthesized benzothiazine compound

4-allyl-2h-1,4-benzothiazin-3(4h)-one (p2),have been synthesized,characterized by nmr spectroscopy,and tested as corrosion inhibitor for mild steel in hcl solution using potentiodynamic polarization curves and electrochemical impedance spectroscopy. potentiodynamic polarization curve measurements showed that the investigated compound was a mixed-type inhibitor. its inhibition efficiencies improve with concentration and reached a maximum at 10-3m. electrochemical impedance spectroscopy (eis) studies suggested that p2 inhibit mild steel corrosion by becoming adsorbate at the metallic/electrolyte surfaces. adsorption of the inhibitor on the mild steel surface was found to obey langmuir's adsorption isotherm. further,the electronic structural calculations using quantum chemical methods were found to be in a good agreement with the results of the experimental studies.