Novel thiophene symmetrical Schiff base compounds as corrosion inhibitor for mild steel in acidic media

• Published in: Corrosion science Vol. 53; no. 4; pp. 1484 - 1488
• Main Authors: Issaadi, S., Douadi, T., Zouaoui, A., Chafaa, S., Khan, M.A., Bouet, G.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-04-2011; Elsevier
• Subjects: A. Hydrochloric acid; A. Mild steel; Anodic; Applied sciences; C. Corrosion; C. Inhibitor; C. Schiff base; Carbon steels; Corrosion; Corrosion environments; Corrosion inhibitors; Corrosion prevention; Electrochemical impedance spectroscopy; Exact sciences and technology; Inhibition; Isotherms; Life Sciences; Metals. Metallurgy; Schiff bases; Surface chemistry; Thiophenes; C. Schiff base; C. Inhibitor; A. Mild steel; C. Corrosion; A. Hydrochloric acid; Hydrochloric acid; Schiff base; Corrosion; Carbon steel; Corrosion protection; C Schiff base; Acid medium; Corrosion inhibitor; Inhibitor; Mild steel
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2011.01.022

► The aim of the present investigation is to examine the inhibitory action of two Schiff bases. ► Compounds are mixed type (cathodic/anodic) inhibitors. ► Inhibition efficiency (% IE) increases with increasing concentration of compounds. ► Adsorption of compounds on mild steel surface obeys Langmuir’s isotherm.
The inhibiting effect of two Schiff bases on the corrosion of the mild steel (MS) in 1
M HCl has been studied by electrochemical impedance spectroscopy (EIS) and Tafel polarisation measurements. The Schiff bases, 4,4′-bis(3-carboxaldehyde thiophene) diphenyl diimino ether (
L
1) and 4,4′-bis(3-carboxaldehyde thiophene) diphenyl diimino ethane (
L
2), were synthesized using 3-carboxaldehydethiophene and its corresponding amine. Polarisation curves reveal that both compounds are mixed type (cathodic/anodic) inhibitors and inhibition efficiency (% IE) increases with increasing concentration of compounds. It is suggested that their effects depend on their concentrations and the molecular structures. Adsorption of compounds on mild steel surface is spontaneous and obeys Langmuir’s isotherm.