Experimental and quantum chemical studies of functionalized tetrahydropyridines as corrosion inhibitors for mild steel in 1 M hydrochloric acid

Jiyaul Haque; Chandrabhan Verma; Vandana Srivastava; M.A. Quraishi; Eno E. Ebenso

Results in Physics (Jun 2018)

Experimental and quantum chemical studies of functionalized tetrahydropyridines as corrosion inhibitors for mild steel in 1 M hydrochloric acid

Jiyaul Haque,
Chandrabhan Verma,
Vandana Srivastava,
M.A. Quraishi,
Eno E. Ebenso

Affiliations

Jiyaul Haque: Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India
Chandrabhan Verma: Department of Chemistry, Faculty of Natural and Agricultural Sciences, School of Chemical and Physical Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa; Material Science Innovation & Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa; Corresponding authors at: Department of Chemistry, Faculty of Natural and Agricultural Sciences, School of Chemical and Physical Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa (C. Verma). Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India (M.A. Quraishi and E.E. Ebenso).
Vandana Srivastava: Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India
M.A. Quraishi: Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India; Center of Research Excellence in Corrosion, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; Corresponding authors at: Department of Chemistry, Faculty of Natural and Agricultural Sciences, School of Chemical and Physical Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa (C. Verma). Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India (M.A. Quraishi and E.E. Ebenso).
Eno E. Ebenso: Department of Chemistry, Faculty of Natural and Agricultural Sciences, School of Chemical and Physical Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa; Material Science Innovation & Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa; Corresponding authors at: Department of Chemistry, Faculty of Natural and Agricultural Sciences, School of Chemical and Physical Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa (C. Verma). Department of Chemistry, Indian Institute of Technology, Banaras Hindu University, Varanasi 221005, India (M.A. Quraishi and E.E. Ebenso).

Journal volume & issue: Vol. 9
pp. 1481 – 1493

Abstract

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Corrosion inhibition property of ethyl 1,2,6-triphenyl-4-(phenylamino)-1,2,5,6-tetrahydropyridine-3-carboxylate (THP-1) and ethyl 2,6-bis(4-methoxyphenyl)-1-phenyl-4-(phenylamino)-1,2,5,6-tetrahydropyridine-3-carboxylate (THP-2) on mild steel (MS) in 1 M HCl have been studied using weight loss, electrochemical, surface morphology (SEM, AFM) and quantum chemical (QC) calculations methods. Results showed that both the functionalized tetrahydropyridines act as an excellent inhibition for mild steel (MS) and it exhibited the maximum inhibition efficiency (IE) of 90.67% (THP-1) and 94.30% (THP-2) at 7.95 × 10−5 M concentration. Results further showed that adsorption of THPs on metallic surface obeyed the Langmuir adsorption isotherm. Potentiodynamic polarization (PDP) study revealed that studied compounds acted as mixed type inhibitors. Electrochemical impedance spectroscopy (EIS) study suggests that the investigated inhibitors inhibit corrosion by adsorbing at the metal/electrolyte interfaces. The SEM, EDX and AFM studies showed that the THPs form a protective covering over the metallic surface that isolates the metal from aggressive acid solution and thereby protect form corrosive dissolution. Quantum chemical (QC) calculations carried out using DFT methods for neutral, solvated and protonated forms of inhibitors provides reasonable support to the experimental findings. Keywords: Mild steel, Acid solution, Corrosion inhibition, Tetrahydropyridines (THPs), Quantum chemical calculations

Published in Results in Physics

ISSN: 2211-3797 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Physics
Website: http://www.journals.elsevier.com/results-in-physics/

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