Ehouman Ahissan Donatien^1,, Bamba Amara², Toure Hadja², Adou Eric³, Kouakou Adjoumani Rodrigue¹, Mariko Kalifa², Dja Ahemou², Niamien Paulin², Yao Benjamin^{3, 4}

Tenoxicam was examined as a copper corrosion inhibitor in 1M nitric acid solution using the mass loss technique and quantum chemical studies, based on density functional theory (DFT) at the B3LYP level with the base B3LYP/6-31G(d). The inhibitory efficiency of the molecule increases with increasing concentration and temperature. The adsorption of the molecule on the copper surface follows the modified Langmuir model. The thermodynamic functions related to the adsorption and the activation processes were calculated and discussed. The calculated quantum chemical parameters correlated to the inhibition efficiency are the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO), the HOMO-LUMO energy gap, hardness (η), softness (S), the dipole moment (µ), the electron affinity (A), the ionization energy (I), the absolute electronegativity (χ), the fraction (∆N) of electrons transferred from (MBT) to copper and the electrophilicity index (ω). The local reactivity was analyzed through the condensed Fukui function and condensed softness indices to determine the nucleophilic and electrophilic attack sites. There is good agreement between the experimental and theoretical results.

Tenoxicam, corrosion inhibition, copper, density functional theory (DFT), mass loss technique