Quantum Chemical Studies on N-Donors Based-Pyrazole Compounds as Corrosion Inhibitors for Steel in Acidic Media

In this study, some possible relationship between the experimental inhibition corrosion in acidic media and the theoretical energy calculations for four series of compounds containing pyrazoles: (A) the first series of compounds, comprises only one pyrazole ring, (B) the second series has two pyrazoles (bipyrazole), (C) the third one contains one pyrazole and one pyridine (pyridyl pyrazole) and (D) the last series concerns tripodal pyrazoles, has presented. These sets of compounds have been tested for their corrosion inhibition properties of steel in low concentration of hydrochloric acid medium. For these compounds, DFT method studies have been performed. They were based on (E-HOMO), (E-LUMO) and the difference (E-LUMO-E-HOMO). The correlation between these two parameters (theoretical and experimental) was shown to be in good agreement for some cases.