Characterization of corrosion products formed on carbon steel in hydrochloric acid medium by 4-(dimethylamino)-1-(6-methoxy6-oxohexyl)pyridinium bromide

• H. Lgaz^1,2, A. Anejjar², R. Salghi², S. Jodeh³, M. Zougagh^4,5, I. Warad³, M. Larouj¹ and P. Sims⁶

¹ Laboratory separation processes, Faculty of Science, Ibn Tofail University, PO Box 242, Kenitra, Morocco
² Laboratory of Applied Chemistry and Environment, ENSA, Ibn Zohr University, PO Box 1136, 80000 Agadir, Morocco
³ Department of Chemistry, An-Najah National University, P. O. Box 7, Nablus, Palestine
⁴ Regional Institute for Applied Chemistry Research, IRICA, E-13004, Ciudad Real, Spain
⁵ Castilla-La Mancha Science and Technology Park, E-02006, Albacete, Spain
⁶ Bob L. Herd Department of Petroleum Engineering, Texas Tech University, box 43111, Lubbock, Texas

Abstract: The inhibition of corrosion of carbon steel in 1 M HCl by the synthesized ionic liquid 4-(dimethylamino)-1-(6-methoxy-6-oxohexyl)pyridinium bromide (DMOPB) is performed by electrochemical, gravimetric techniques and surface analysis techniques. The efficiency of inhibition increases with the inhibitor concentration and reached 93% at 10^-3 M. The polarization data indicate that the tested inhibitor is a mixed type. The adsorption of the inhibitor on the surface of the steel in 1 M HCl follows the adsorption isotherm Langmuir. The study of the effect of temperature (303–333 K) on the behavior of the steel in 1 M HCl in the absence and presence of 10^-3 M of the inhibitor shows that the inhibitory efficiencies increase with temperature in this studied range. The corresponding activation parameters in the absence and presence of inhibitor were determined and discussed. The inhibition efficiency was closely related to orbital energies (EHOMO and ELUMO). The correlation between quantum parameters and experimental inhibition efficiency has been validated. Scanning electron microscopy images revealed that the inhibitor formed protective film on mild steel surface.

Keywords: ionic liquid, inhibition, carbon steel, acid, free energy

Int. J. Corros. Scale Inhib., 2016, 5, no. 3, 209–231 PDF (1 135 K)
doi: 10.17675/2305-6894-2016-5-3-3

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