**Author details**

*Corrosion Inhibitors*

**3. Conclusion**

**Acknowledgements**

**Conflict of interest**

**Notes/thanks/other declarations**

On the basis of the above discussion of the alkylation effect on ionic liquids in various analyses, it can be concluded that structural effect is a considerable key factor in enhancing corrosion protection performance of metal in acid medium. Alkylation of the heterocyclic cation in the ionic liquid, particularly on N1/N2 of imidazolium, benzimidazolium, or N1 of pyridinium or P1 phosphonium, facilitates the physical/chemical properties of the ionic liquids compared to unalkylated ionic liquid. Not only had the physical/chemical properties changed but also electrochemical properties. This effect has been discussed with respect to various studies, such as electrochemical behavior, surface protection, electronic properties quantum chemical analysis (QCA), and hydrogen gas evolution. Adsorption of ionic liquid is favored mostly when it is being structurally modified as a result of passive film adsorption on the metal surface, which keeps the environment corrosion free. The reason for the extraordinary maturity of the alkylated ionic liquid could be described using theoretical study. This will support the alkylated or structurally modified ionic liquid electronic properties. The electron-donating nature of ionic liquid is being increased by alkylation. As a result, the resonance effect also increased, which contributes to the stability of the ionic liquid compared to the unalkylated form. The use of ionic liquid as a corrosion inhibitor is

predominant and more efficient for structural modification.

(Deemed to be University), Bengaluru for carrying out this work.

The author of this manuscript has no conflict of interest.

The author is thankful to his management for their help in assisting his work on this chapter. Dr. P. Kannan is acknowledging Centre for Research, CHRIST

I express my heartfelt thanks to my friends Mr. P. Mathavan, Dr. L. Mohan, and

Dr. K. Vidya for their constant support and encouragement on this endeavor.

**34**

Perumal Kannan\* and Anitha Varghese Department of Chemistry, CHRIST (Deemed to be University), Bengaluru, Karnataka, India

\*Address all correspondence to: kannanperumal104@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
