Synergistic and hydrogen bonded interaction of alkyl benzimadazoles and urea pair on mild steel in hydrochloric acid: Adsorption, electroanalytical and theoretical studies.

Synergistic hydrogen bonded interaction of alkyl benzimidazoles and urea and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, electrochemical impedance spectroscopy (EIS), adsorption, surface studies and basic computational calculations. Quantum chemical approach was used to calculate some electronic properties of the molecules for the sake of correlating the synergistic interaction, inhibition properties and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to parameters, such as total energy, energy of highest occupied molecular orbital ( E HOMO ), energy of lowest unoccupied molecular orbital ( E LUMO ) and gap energy (Δ E ). Urea interacts with benzimidazoles up to a bond length of approximately 1.8 Å. This represents the formation of a hydrogen bond between urea and benzimidazole molecules. Polarization and impedance studies also showed synergistic interaction between urea and benzimidazoles which offer extended inhibition efficiency toward mild steel in hydrochloric acid. [ABSTRACT FROM AUTHOR]