Heterocyclic Corrosion Inhibitors

This study investigates the use of new heterocyclic compounds, specifically Imidazole derivatives, as corrosion inhibitors for steel in acidic media. The objective is to establish correlations between molecular structure and corrosion inhibition based on the substituent effect in each series of molecules. The study employs various techniques, including gravimetry, electrochemical impedance spectroscopy, polarization measurements, scanning electron microscopy, and molecular dynamics simulation. Results show a direct link between the parameters obtained and the changing substituent in the basic structure of each series. For the Imidazole series, inhibitors Imid1, Imid2, and Imid3 effectively inhibit corrosion of steel with efficiencies reaching up to 95%, with decreasing donor effects leading to decreasing inhibition efficiency. Inhibitors were classified based on their substituent and its position. The concentration and temperature effects were studied, with the inhibitors acting via chemisorption on the steel surface following the Langmuir model. Adsorption of the inhibitors on the metal surface was confirmed by spectroscopic characterization of the protective layer.