Electrochemical and Chemical Studies of some Benzodiazepine Molecules as Corrosion Inhibitors for Mild Steel in 1 M HCl

• Published in: International journal of electrochemical science 2014-12, Vol.9 (12), p.8283-8298
• Main Authors: Niouri, W., Zerga, B., Sfaira, M., Taleb, M., Touhami, M. Ebn, Hammouti, B., Mcharfi, M., Al-Deyab, S.S., Benzeid, H., Essassi, El M.
• Format: Article
• Language: English
• Subjects: Adsorption; Benzodiazepine; Corrosion inhibition; Hydrochloric acid; Mild steel
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)11047-9

The corrosion inhibition of mild steel in molar hydrochloric acid solution by : 2,3-dihydro-1H- pyrrolo[2,1c][1,4] benzodiazepine-5,11(10H,11aH)-dione (BZD1), 2,3-dihydro-1H-pyrrolo[2,1c][1,4] benzodiazepine-5,11(10H,11aH)-dithione (BZD2) and 3-phenyl-1,2,4-triazolo[3,4-c]pyrrolo[1,2a] [1,4]benzodiazepine-9-thione (BZD3) has been investigated at 308 K using electrochemical and chemical methods. Current-voltage measurements showed that these compounds were good inhibitors without changing the mechanism of corrosion process. EIS measurements showed that the charge transfer resistance increases whereas the double layer capacitance decreases with the inhibitor concentration. The inhibiting efficiency increased with rise concentration of the studied inhibitors and was corroborated by the three undertaken techniques. BZD3 showed better protection properties even at relatively higher temperatures. The associated activation energy of corrosion process and standard free adsorption energies, for the best inhibitor BZD3, have been determined. BZD3 was adsorbed on the mild steel surface according to Langmuir isotherm adsorption model. Explanations by quantum chemical descriptors to be correlated with inhibition efficiency are under progress and should be published as soon as possible.