Computational Assessment of the Corrosion Inhibition Potentials of Some Polyamines Using Density Functional Theory

International Journal of Research and Innovation in Applied Science (IJRIAS) | Volume V, Issue X, October 2020 | ISSN 2454–6186

 Computational Assessment of the Corrosion Inhibition Potentials of Some Polyamines Using Density Functional Theory

Kufre E. Essien^1*, I. O. Ekpenyong², Okon, O. E.³ and Etiowo G. Ukpong^4
1Department of Chemistry, Akwa Ibom State University, P.M.B. 1167, Ikot Akpaden, Mkpat Enin, Nigeria
^2,3,4Department of Science Technology, Akwa Ibom State Polytechnic, Ikot Osurua, P.M.B. 1200, Ikot Ekpene, Nigeria
Corresponding author

Abstract: The theoretical studies of corrosion inhibition potentials of three polyamine derivatives {2, 3–diaminophenazine (DAPH); 1, 2-diaminoanthraquinone (DAA) and 2, 3-diaminonaphthalene (DAN)} were investigated using Density Functional Theory with RHF/STO-6G* method. Quantum chemical parameters (such as EHOMO, ELUMO, energy gap, ionization energy, electron affinity, global hardness, global softness, electrophilicity index, back donation, absolute electronegativity) were used to predict the corrosion inhibition potentials. Corrosion inhibition potentials increased with increase in EHOMO, absolute electronegativity, global softness, electrophilicity index and decreasing energy gap, ELUMO, global hardness and back donation. It was observed that the predictive corrosion inhibition potentials decreased as follows: DAPH > DAA > DAN. Also, the sites of likely electrophilic attack were located on atoms (nitrogen and oxygen) as shown by high negative mulliken charges of these atoms. Molecular electrostatic potentials (MEPs) also provided further insight into the binding sites of these molecules on the metal-surface.

Keywords: Metal, Corrosion, Inhibition, Quantum, polyamine

I. INTRODUCTION

Globally, challenges facing industries right from the inception, is corrosion of metals like Fe, Ni, Al, Cr, Ti and their alloys when exposed to aggressive media [1–3]. National Association of Corrosion Engineers reported that the global corrosion expenditure is about US $ 2.5 trillion; and proper implementation of measures for prevention of corrosion can save more than $ 875 billion annually [4]. Hence, this can be successfully accomplished with effective corrosion inhibitors.

Among several measures of corrosion prevention, inhibitors of corrosion have been widely applied in various fields such as, petroleum extraction and refining, iron and steel, electric power, construction and several others due to economy and high efficiency [5–7]. The extent upon which the inhibitor interacts on the surface of metal makes the inhibitor more effective for corrosion prevention [8–10]. In industries, most

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