An experimental and theoretical approach towards understanding the inhibitive behavior of a nitrile substituted coumarin compound as an effective acidic media inhibitor

The inhibiting ability of 2H-chromen-2-one (Ch) or coumarin and its corresponding nitrile substituted compound 2-Oxo-2H-chromen-3-carbonitrile (ChCN), has been studied using electrochemical techniques, SEM and theoretical calculation methods The Langmuir adsorption isotherm model best described the adsorption characteristics of the compounds under study. Scanning electron microscopy studies revealed the formation of a protective inhibitor layer on the mild steel surface. Quantum chemical parameters obtained using the density functional theory (DFT) supported the experimental results. Substitution of a -CN group was seen to increase the inhibitor efficiency up to 98%.