Regularities and mechanism of the anti-corrosion action of “green” inhibitors in neutral aqueous environments

By-product extracts of the fruit processing act as steel corrosion “pro-inhibitors” in a neutral aqueous solution. As a result of the chemical transformation in the volume of the electrolyte, flavanol-anthocyanin, and flavanol-aldehyde adducts are formed, which are adsorbed on the steel surface and block the access of corrosive medium to the metal surface, thereby causing secondary inhibition of the corrosion process. The polymerization products have more carbon atoms in the skeletal structure, located according to the aromatic scheme, as well as polar and aromatic functional groups. Using quantum chemical methods, it was established that such structures have a better ability to interact with the metal surface through oxygen heteroatoms and due to π‑interaction.