Microwave and ultrasound irradiations for the synthesis of environmentally sustainable corrosion inhibitors: An overview

The emerging field of green chemistry requires greener pathway for chemical transformations with minimum by-products generation and that avoid the implementation of conventional toxic chemicals, whenever possible. In view of this several newer strategies such as chemical synthesis under solvent free condition, use of solid supported reagents, mechanochemical mixing (mechanical grinding) and implementation of non-conventional activation using microwave and ultrasound irradiations have been developed. Owing to their sustainable nature, microwave and ultrasound irradiations have been implemented for several chemical transformations in last 30 years. Increasing demands of the green chemistry also attracted significant attention for the scientists and engineers working in the field of corrosion science and engineering. Numerous organic compounds have been synthesized using non-conventional energy sources and applied as efficient corrosion inhibitors in aggressive media for metals and alloys. Present review article describes the collection of the corrosion inhibitors synthesized using energy efficient microwave and ultrasound irradiations. The review article also defined several aspects of the microwave and ultrasound assisted reactions and the theories behind them.