The effect of structure parameters on the corrosion inhibition effect of some heterocyclic nitrogen organic compounds

Abstract

The corrosion inhibition effect of pyridine, quinolone, acridine and their n-hexadecyl derivatives were studied by quantum chemical methods. The density functional theory (DFT) at the B3LYP/6-311G + (d,p) basis set level, ab initio calculations using the HF/6-311G + (d,p) and semi-empirical PM6 methods were performed to investigate the correlation between its molecular structure and the corresponding corrosion inhibition efficiency (%IE). Inspection of the calculated parameters and corrosion inhibition efficiencies were made to observe any clear links, which might exist between them. Possible correlations between experimental inhibition efficiencies and parameters such as dipole moment (DM), highest occupied (EHOMO) and lowest unoccupied (ELUMO) molecular orbitals and the differences between them, HOMO-LUMO gap (ΔE), as well as some structural characteristics were investigated. Computational studies have been used to find the most stable adsorption sites for these compounds. This information help to gain further insight about corrosion system, such as the most likely point of attack for corrosion on iron, the most stable site for adsorption and the binding energy of the adsorbed layer