Computational Study for Molecular Properties of Some of the Isolated Chemicals from Leaves Extract of Guiera Senegalensis as Aluminium Corrosion Inhibitor

Abstract

The present work describes the computational methods for the corrosion inhibition of aluminium using three selected chemical constituents (5-methyldihydroflavasperone, 5-methylflavasperone and methoxylated naphthyl butanone) reportedly obtained from the leaves extract of Guirea senegalensis. Quantum chemical calculations including EHOMO, ELUMO, energy gap (ΔE), electronegativity (χ), global hardness (η) and fraction of electrons transfer from the inhibitor molecule to the aluminium surface (ΔN) were calculated. The local reactive sites through Fukui indices which explain the effect of structural features of these components in relation to electrophilic and nucleophilic point of attack were evaluated. The similarities in quantum chemical parameters for the compounds obtained revealed that the adsorption strengths of the molecules will be mostly determined by molecular size rather than electronic structure parameters. Fukui indices showed that the point of interaction of inhibitor molecule with the Al(l10) surface were through aromatic carbon atom rich in pi-electrons and oxygen atom of the alkanone functional group in the inhibitor molecules. Molecular dynamics simulations describing the adsorption behavior of the inhibitor molecule on Al(110) surface through Forcite quench molecular dynamics were carried out. The compounds were found to all obey the mechanism of physical adsorption because of their relatively low adsorption energies.

Theoretical Study and Adsorption Behavior of Urea on Mild Steel in Automotive Gas Oil (AGO) Medium

“…Ureа is аn оrgаnо-оxygen cоmpоund with the fоrmulа CО(NH2)2. The presence оf nitrоgen аnd оxygen mаkes ureа аn effective cоrrоsiоn inhibitоr [22]. Organic inhibitor compounds containing heteroatoms such as nitrogen, oxygen, sulphur, or phosphorous in a conjugated system have been identified to possess excellent corrosion inhibiting properties as corrosion inhibitors [23,24].…”

“…The presence of nitrogen and oxygen makes urea an effective corrosion inhibitor [21]. Organic inhibitor compounds containing heteroatoms such as nitrogen, oxygen, sulphur, or phosphorous in a conjugated system have been identified to possess excellent corrosion inhibiting properties as corrosion inhibitors [22,23]. Inhibition by organic compounds form strong film protection on the surface of the mild steel through the adsorption process [24,25].…”