Anti-corrosive properties of new Benzothiazine derivative on mild steel corrosion in 1 M HCl: Experimental and theoretical investigations

The effect of adding [(e)-2-benzylidene-4-(prop-2-ynyl)-2h-benzo[b][1,4]thiazin-3(4h)-one] named (p1),newly synthesized on the electrochemical behavior of mild steel in molar hydrochloric acid was investigated by using the potentiodynamic polarization and electrochemical impedance spectroscopy (eis) measurements. eis diagrams show that adsorption of (p1) increases the transfer resistance and decrease the capacitance of interface metal/solution. the inhibition efficiency for this compound studied increased with the increase in the inhibitor concentrations to attain 94% at the 10-4 m of (p1). the inhibitor (p1) was adsorbed on the steel surface according to the langmuir adsorption isotherm model. from the adsorption isotherm,some thermodynamic data for the adsorption process were calculated and discussed. kinetic parameters activation such as activation energy,entropy and enthalpy of activation were evaluated from the effect of temperature on corrosion and inhibition processes. correlation between quantum chemical calculations and inhibition efficiency of the investigated compound is discussed using the density functional theory method (dft).