Experimental and theoretical investigations of 1,3,5-tris(4-aminophenoxy)benzene as an effective corrosion inhibitor for mild steel in 1 M HCl

Abstract

The amine derivative 1,3,5-tris(4-aminophenoxy) benzene (TAPOB) was newly synthesized, characterized and evaluated for the first time by weight loss, electrochemical methods and quantum chemical calculation. The inhibition efficiency of TAPOB was as high as 95% according to gravitational method. Information based on potentiodynamic polarization indicated that TAPOB was a mixed-type inhibitor. Electrochemical impedance spectroscopy study proved that TAPOB could adsorb on mild steel surface and impart high charge-transfer resistance. The thermodynamic results demonstrated that the adsorption process of TAPOB on mild steel surface obeyed to Langmuir adsorption isotherm and involved both physical and chemical adsorption. The surface analysis of mild steel further suggested that TAPOB existed on the metal surface to form a protective film by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) technique. The relationship between the inhibition efficiency and molecular structure was discussed via theoretical calculation, which was in a good agreement with the experiment results. All these evidence revealed that TAPOB was an effective and potential amine-typed corrosion inhibitor.