Temperature Effect, Activation Energies and Thermodynamics of Adsorption of ethyl 2-(4-(2-ethoxy-2-oxoethyl)-2-p- Tolylquinoxalin-1(4H)-yl)Acetate on Cu in HNO3
The detailed study of corrosion behaviour of copper in 2M nitric acid solution in the presence
and absence of 2-(4-(2-ethoxy-2-oxoethyl)-2-p-tolylquinoxalin-1(4H)-yl)acetate (Q1) was investigated
using weight loss method at various temperatures from 303 to 343 K. The inhibitor showed 97% inhibition
efficiency at its optimum concentration 10-3M at 303K and decreased at higher temperatures. The
thermodynamic parameters such as, equilibrium constant, adsorption heat and adsorption entropy
were obtained. The various parameters of activation determining the kinetic data such as energy,
enthalpy and entropy at different concentrations of the inhibitor were evaluated and discussed. The
adsorptive behaviour of Q1 followed Langmuir-type isotherm. The standard free energies of adsorption
were negative at different temperatures tested, reûecting better inhibition performance.