Abstract

ALOUI, S. et al. New Mechanism Synthesis of 1,4-Benzothiazine and its Inhibition Performance on Mild Steel in Hydrochloric Acid. Port. Electrochim. Acta [online]. 2009, vol.27, n.5, pp.599-613. ISSN 0872-1904.

1-(3-methyl-4H-1,4-benzothiazin-2-yl)ethanone (1,4-BT) was synthesised via a new mechanism. 1,4-BT was thereafter tested as corrosion inhibitor of mild steel in hydrochloric solution at 293 K by weight loss measurements and electrochemical techniques (potentiodynamic polarisation, polarisation resistance, impedance spectroscopy (EIS)). Inhibiting efficiency (E%) increased with concentration and reached highest values up to 98% even at low concentration with changing the mechanism of the corrosion process. Results obtained showed that the inhibitor studied was an efficient inhibitor, especially in cathodic domain. The temperature effect on the corrosion behaviour of mild steel in 1 M HCl with and without 1,4-BT at 5 10^-3 M was studied in the temperature range from 293 to 333 K. E% remains the same even at high temperature. The adsorption free energy and activation parameters for the mild steel dissolution reaction, in the presence of 1,4-BT, were determined. 1,4-BT is adsorbed on the mild steel surface according to a Langmuir isotherm adsorption model.

Keywords : mild steel; corrosion inhibition; 1,4-benzothiazine; thermodynamic parameters.

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