The effect of inhibitor structure on the corrosion of copper in 0.6 M aqueous sodium chloride solution

Department of Chemistry, Bengal College of Engineering and Technology, Durgapur-713 212,

West Bengal, India

E-mail : murarimohan_nandi@yahoo.co.in

Manuscript received online 30 March 2015, accepted 15 October 2016

The inhibition effect of glycine (1), aspartic acid (3) and their various derivatives namely N-benzenesulphonyl glycine (2), N-benzenesulphonyl aspartic acid (4), α-benzenesulphonamido-β-2-benzimidazolyl-propionic acid (5), 1- benzenesulphonamido-1,2-bis(2-benzimidazolyl)ethane (6), α-benzenesulphonamido-β-2-(1,4,5,6-tetrahydropyrimidinyl) propionic acid (7), 1-benzenesulphonamido-1,2-bis-2-(1,4,5,6-tetrahydropyrimidinyl) ethane (8), α-benzenesulponamido- β-(2-imidazolynyl)propionic acid (9) and 1-benzenesulphonamido-1,2-bis(2-imidazolynyl)ethane (10) against the corrosion of copper in 0.6 M aqueous sodium chloride solution (pH 6) have been studied using weight loss and potentiodynamic polarization methods. The inhibition efficiency of these compounds increases in the order : 1 < 2 < 3 < 4 < 5 < 6 < 7 < 8 < 9 < 10. Compounds having zwitter ion structure under the experimental condition are found to be less effective. Imidazoline derivatives are found to be better corrosion inhibitor for copper. The adsorption of the inhibitors follows Langmuir isotherm. The adsorption free energy indicates chemisorptions of the inhibitors on the metal surface.