Molecular structure of amino alcohols on aluminum surface

• Chemical calculations were performed on ethanolamines as corrosion inhibitors for aluminum surface.
• Chemical parameters were calculated.
• The calculations were extended to protonated inhibitors and solvent effect.
• The mode of the interactions of the inhibitors with the metal surface was studied.

Quantum chemical calculations were applied on monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) as corrosion inhibitors for aluminum exterior using ab initio Møller–Plesset (MP2) and Density Function Theory (DFT-B3LYP) at 6-311++G(d,p) ground set. Quantum chemical parameters such as the maximum employed molecular orbital energy (EHOMO), the minimum unemployed molecular orbital energy (ELUMO), energy disparity (ΔE), dipole moment (μ), sum of the total negative charge (TNC), molecular volume (MV), electronegativity (χ), chemical potential (Pi), global hardness (η), softness (σ) and the fraction of electrons transferred (ΔN), were calculated. Further calculations were done to explore the effects of inhibitors and solvent. Furthermore, the inhibitors’ interactions with the metal exterior were studied by applying COMPASS method. R2 values showed good correlations between the corrosion inhibitors’ effectiveness and several quantum parameters.