ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Corrosion performance of Schiff base derived from 2, 5-dimethoxybenzyaldehyde: X-ray structure, experimental and DFT studies

Samson Ifeanyi Eze, Collins U. Ibeji, Ekemini D. Akpan, Chigozie Julius Ezeorah, Obinna Chibueze Okpareke, Tania Groutso, Simeon Atiga, Kovo G. Akpomie, and Lilian Chinenye Ekowo

Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Nigeria

E-mail: ugochukwu.ibeji@unn.edu.ng

Received: 26 March 2022  Accepted: 17 April 2022

Abstract:

A Schiff base, 2-[(E)-(2,5-dimethoxybenzylidene) amino]-4-methylphenol (DMPC) was synthesized by condensation reaction of 2,5-dimethoxybenzaldehyde with 2-amino-4-methylphenol at 35 °C. The integrity of the synthesized compound was determined by spectroscopic techniques such as FT-IR, NMR, UV/visible and ESI–MS. Quality single crystals of the compound were also harvested and analyzed using X-ray diffraction (XRD) method. The XRD data reveal that the compound crystallized out in monoclinic crystal system with space group of C2/c and Z = 8-unit cell. The corrosion inhibition performance of the Schiff base on mild steel in 1.0 M HCl was evaluated using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), surface analysis and computational studies. The inhibition efficiency obtained from PDP and EIS at the optimum inhibitor concentration is 96.56% and 97.02%, respectively. Data from polarization measurement indicate that the compound acted as a mixed-type inhibitor in the tested media. The adsorption study carried out showed that Langmuir adsorption mechanism was followed since R² value is very close to unity, and also, the slope of the graph approaches unity. The compound was found to adsorb on the mild steel surface by both physisorption and chemisorption adsorption mechanisms. The EDX spectra analysis shows that oxygen was eliminated from the mild steel surface while SEM result portrays significant reduction of mild steel corrosion in the presence of the studied inhibitor, compared with the blank. The results obtained from DFT calculations agree the experimental findings.

Keywords: Corrosion; DFT; Electrochemical impedance spectroscopy; X-ray diffraction method

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02244-7

Chemical Papers 76 (8) 5187–5200 (2022)