Theoretical and experimental evaluation of the anticorrosion properties of new Coumarin's derivatives

Coumarin has been widely found in some prevailing plants. As green biodegradable inhibitors, the corrosion of mild steel (MS) in 1.0 M aqueous HCl was investigated gravimetrically and electrochemically in the presence and absence a recommended dose (200 ppm) of new synthesized Coumarin’s derivatives {HCA-β-Ala (I), HCA-β-Ala-OMe (II), HCA-β-Ala-Hyd (III) and HCA-β-Ala-Gly (IV)}. The corrosion inhibition efficiency was found exceed 95% in the sequence HCA-β-Ala (I) < HCA-β-Ala-OMe (II) < HCA-β-Ala-Hyd (III) < HCA-β-Ala-Gly (IV). Finally, the density function theory (DFT) was applied to investigate the molecular electrostatic potential (MEP) to identify the interaction of the evaluated compounds on the metallic surface.