Synthetic Green Corrosion Inhibitors

Abstract

Recently, one step multicomponent reactions (MCRs) and nonconventional microwave (MW) and ultrasound (US) irradiation have emerged as highly efficient methods for various chemical transformations. The compounds derived from MCRs, MW and US methods are widely used as corrosion inhibitors for different metals and alloys in various electrolytes. More so, compounds synthesized from natural resources such as carbohydrates and amino acids are also treated as green corrosion inhibitors. Recently, water, ionic liquids (ILs), supercritical CO2 and polyethylene glycol have been established as green solvents and compounds synthesized in these solvents can be treated as green alternatives for corrosion inhibitors. Study of the literature indicates that ILs and PEG are used as corrosion inhibitors and as solvents for the synthesis of numerous green corrosion inhibitors. These synthetic corrosion inhibitors become effective by adsorbing on the metal surface, mostly through the physisorption mode. These compounds behave as mixed- and interface-type corrosion inhibitors. Their adsorption on metallic surfaces is reinforced with numerous surface investigations including SEM, XRD, XPS, EDX and AFM etc. Mechanisms of interactions of these compounds with the metallic surface are greatly studied by computational studies mainly through DFT, MDS and MCS methods.