Indole and Its Derivatives as Corrosion Inhibitors

Corrosion of metallic materials has great socio-economic and environmental implications on every nation of the world. Efforts to combat the menace of corrosion include formulation of corrosion inhibitors among other methods. Over the years, thousands of organic and inorganic inhibitors have been tested as potential anticorrosive materials. Recent studies show that inorganic inhibitors are been substituted with organic inhibitors because of the environmental worries they generate. The use of chemical compounds as inhibitors of metallic corrosion in diverse electrolytic environments have become popular in recent years because of their effectiveness, practicality, and low toxicity. Indoles belong to a class of aromatic heterocyclic organic compounds that have been reported to adsorb and offer good surface coverage to metals in different electrolytic media. Factors such as the presence of polar groups, pi electrons, and heteroatoms (S, P, O, and N), as well as aromaticity, substantially enhance the inhibitive effect of these classes of compounds. Other factors include their molecular size, solubility, solution temperature, and nature of the electrolytic media. This chapter presents a literature study on the exploration of indole and its compounds as inhibitors of metallic degradation in different electrolytic environments via experimental and computational techniques.