Copper Corrosion Inhibition in 1 M HNO3 by Two Benzimidazole Derivatives

Abstract

Corrosion behavior of copper in 1 M nitric acid containing either 2-mercaptobenzimidazole (MBI) or 2-thiomethylbenzimidazole (TMBI) was investigated experimentally and theoretically via weight loss method and quantum chemical approaches. It was found that the two compounds exhibit a very good performance as inhibitors for copper corrosion in the studied medium. Results show that the inhibition efficiencies increase with increasing temperature and increasing concentration of the inhibitors. It has been found that the studied compounds adsorb onto copper according to the modified Langmuir adsorption isotherm and the kinetic/thermodynamic isotherm of El-Awady. The thermodynamic adsorption parameters and kinetic corrosion parameters were determined and analyzed; on the bases of these parameters both physisorption and chemisorption were suggested for the studied compounds. Furthermore, the quantum chemical properties/descriptors most relevant to their potential action as corrosion inhibitors have been calculated. They include E HOMO , E LUMO , energy gap (ΔE), dipole moment (μ), hardness (η), softness (σ), the fractions of electrons transferred (ΔN), electrophilicity index (ω), and the total energy change (ΔE T ). The theoretical results were found to be consistent with the experimental data reported.

Dry and wet lab analysis on benzofused heterocyclic compounds as effective corrosion inhibitors for mild steel in acidic medium

“…HOMO is often associated with the electron donating ability of a molecule. High E HOMO values indicate that the molecule has a tendency to donate electrons to appropriate acceptor molecules with low energy empty molecular orbital [51]. Increasing values of the E HOMO enable adsorption and hence inhibition by influencing the transport process through the adsorbed layer.…”

The Inhibition Effect of Heterocyclic Compounds towards the Corrosion of Metals in Different Media: over view

“…The inhibition efficiencies increase with increasing temperature and increasing concentration of the inhibitors [37].…”

Experimental and theoretical evaluation of two benzimidazole derivatives for steel corrosion protection in HCl

“…In the frontier molecular orbital theory, the chemical reactivity of molecule is a function of interaction between HOMO and LUMO of the reacting species . E HOMO often renders the electron‐donating ability.…”