N-heterocycle compounds as aqueous phase corrosion inhibitors: A robust, effective and economic substitute

The use of heterocyclic compounds, especially nitrogen based heterocyclic compounds (N-heterocycles), is one of the most popular methods of corrosion mitigation in aqueous phase. Obviously, N-heterocycle compounds adsorb on the metal surface employing non-bonding electrons of nitrogen and π-electrons of side chain or aromatic ring(s) and form corrosion protective film. N-heterocyclic compounds including imidazole, pyridine and quinoline are extensively employed for corrosion mitigation. In this report anticorrosion potential of imidazole, pyridine and quinoline and their derivatives is surveyed. These compounds slow down the overall the corrosion rate (C_R) by retarding both anodic and cathodic half-cell reactions. Through their adsorption, these compounds block the active sites and enhance the value of charge transfer resistance for corrosion process. Literature investigation shows that imidazole, pyridine and quinoline and their derivatives act as mixed-type corrosion inhibitors. Outcomes of computational modeling suggest that imidazole, pyridine and quinoline and their derivatives interact with metal surface using donor–acceptor mechanism and nitrogen atom is greatly participated in the interactions.