Experimental and computational studies on the inhibition performance of the organic compound “2-phenylimidazo [1,2-a]pyrimidine-3-carbaldehyde” against the corrosion of carbon steel in 1.0 M HCl solution

The inhibition effect of the synthesized organic compound 2-phenylimidazo [1,2-a] pyrimidine-3-carbaldehyde (IPM) on the corrosion of carbon steel (C-steel) in hydrochloric acid solution. The experiments were carried out using gravimetric (weight loss) measurements, potentio dynamic polarization and, impedance spectroscopy techniques. The results revealed that the corrosion rate increases with the increase of the concentration of IPM inhibitor. Polarization studies indicate that this compound acts as a mixed type inhibitor. The adsorption of the inhibitor was well described by the Langmuir isotherm model. Furthermore, quantum chemical calculations were carried out using density functional theory (DFT) at the B3LYP/6-31+G(d,p) level for all atoms by Gaussian 09 W program, to provide molecular based explanations for the inhibitive effects of the compound. The molecular dynamics simulation results show that the single molecule (IPM) can adsorb on the α-Fe2O3(111) surface in hydrochloric acid as solution through the oxygen and nitrogen atoms as well as pi-electrons in the imidazo-pyrimidine structure. Theoretical results are in accordance with experimental data to good extend.