Investigation of Aniline and N,N-Dimethylaniline as Acidic Corrosion Inhibitor: a Structure–Efficiency Relationship Study

In this study, aniline and N,N-dimethylaniline was evaluated as corrosion inhibitor for the A3 steel in 5% HCl solution, by the way of gravimetric measurements, and the structure-efficiency relationship was studied. With the result under different concentration and temperature, from 303 to 343 K, the inhibition efficiency of the two inhibitors was compared. The adsorption of aniline and N,N-dimethylaniline on the A3 steel is figured out conforming Langmuir type isotherm. From the comparison of the thermodynamic activation parameters (ΔG, ΔH, ΔS and Ea), it reveals that aniline is easier to absorb on the steel, which can be attributed to the stereochemistry of the two compounds.