Synthesis, crystal structure, experimental and theoretical studies of corrosion inhibition of 2-((4-(2-hydroxy-4-methylbenzyl)piperazin-1-yl)methyl)-5-methylphenol – A Mannich base

• Published in: Journal of molecular structure Vol. 1219; p. 128539
• Main Authors: Ayeni, Ayowole O., Akinyele, Olawale F., Hosten, Eric C., Fakola, Emmanuel G., Olalere, Job T., Egharevba, Gabriel O., Watkins, Gareth M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-11-2020
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2020.128539

A new Mannich base; 2-((4-(2-hydroxy-4-methylbenzyl)piperazin-1-yl)methyl)-5-methylphenol (HMP) was synthesized, characterized by elemental analysis, UV/Vis, 1H and 13C NMR spectroscopy, and examined as an inhibitor for the corrosion of a mild steel surface in 0.2 M sulphuric acid (H2SO4) solution using weight loss and potentiodynamic polarization techniques. The X-ray structure of the Mannich base was also reported. The inhibition efficiency increases with increasing inhibitor concentration and decreases over 96 h. Potentiodynamic polarization measurements showed that the inhibitor is of mixed type. The relationship between the molecular structure of HMP and its inhibitory properties was studied using density functional theory (DFT) calculations.
•Crystal structure of a new Mannich base denoted as HMP is reported.•UV and NMR spectroscopic data of HMP.•Inhibition efficiency was evaluated by weight loss and electrochemical techniques.•DFT calculations of the properties of HMP and its protonated form.