Abstract

Inhibition of corrosion of zinc in 0.1m H2So4 by 5-amino-1-cyclopropyl-7-[(3r,5s)3,5-dimethylpiperazin-1-yl]-6,8-difluoro-4-oxo-quinoline-3-carboxylic acid (A)

Author(s): N.O.Eddy, A.S.Ekop

Effect of A on the corrosion of zinc has been studied by using weight loss and gasometric methods. The study revealed thatAinhibits the corrosion of zinc with corrosion efficiency ranging from 34.64-73.50%. The kinetics of uninhibited and inhibited corrosion reaction of zinc is found to be first order. Values of rate constant and half-life ranged from 0.1076-1.10893 and 24- 154days respectively.Average values of activation energy (Ea) of the inhibited corrosion reaction (5.1751J/mol) was higher than average values of activation energy obtained for the uninhibited corrosion reaction(-13.0760J/ mol).Average values of enthalpy change(Hads =-15.1751J/mol) and entropy change (Sads=-279.8631J/mol) and free energy of adsorption (Gads= - 87.5829KJ/mol) reveal that the inhibited corrosion reaction of zinc is spontaneous and exothermic. From the calculated thermodynamic parameters the inhibited corrosion reaction of zinc is controlled by activation complex and proceeds via chemical adsorption. An adsorption characteristic of the studied inhibitor(A) is found to obey the classical isotherm of Lagmuir.