Corrosion inhibitive evaluation and DFT studies of 2-(Furan-2-yl)-4,5-diphenyl-1H-imidazole on mild steel at 1.0M HCl

A novel heterocyclic compound 2-(Furan-2-yl)-4,5-Diphenyl-1H-Imidazole (FDPI) was synthesized by a simple and cost effective one pot synthetic protocol and the structure of FDPI was confirmed by FT-IR, H-1 NMR and C-13 NMR spectra. The corrosion inhibition activity of FDPI was investigated using gravimetric and electrochemical methods. It resulted a maximum inhibition efficiency of 95.84% at 10 mmolL(-1) concentrations of FDPI. The excellent inhibition efficiency is reasoned as the adsorption of FDPI on the mild steel surface as a protective layer immersed in the 1 M HCl. The adsorbed layer obeys Langmuir adsorption isotherm and the Delta G(ads)(o) values of FDPI suggested that process involves physisorption. The polarization curves showed that the FDPI behaves as a mixed type inhibitor. Surface morphology studied by SEM confirmed the formation of a protective film of FDPI on the mild steel surface. The computational studies using DFT have been analyzed for the FDPI to determine the HOMO-LUMO energy gap.