Copper corrosion inhibition in nitric acid solution by 2-(1,3-dihydrobenzimidazol-2-ylidene) -3-oxo-3-(pyridin-3-yl) propanenitrile: Gravimetric, Quantum chemical and QSPR studies

Abstract

The metal corrosion threat in the metallurgical industry is becoming increasingly important. So in this work, the inhibition properties of 2-(1,3-dihydrobenzimidazol-2-ylidene)-3-oxo-3-(pyridin-3-yl) propanenitrile for copper corrosion in 1 M nitric acid medium were evaluated by mass loss technique, density functional theory (DFT) and quantitative structure-property relationship (QSPR) model. The results show that this compound was excellent anticorrosive properties with a maximum inhibition efficiency of 89.39 % for a concentration of 0.2 mM at 323 K. The inhibition efficiency increases with increasing temperature and inhibitor concentration. Adsorption isotherms reported that the molecule adsorbs on copper surface according to Langmuir isotherm. Thermodynamic adsorption and activation parameters were determined and analyzed. They revealed spontaneous adsorption and a strong interaction between the molecule and copper surface. DFT calculations at the B3LYP level with 6-31G(d,p) and 6-311G(d,p) basis set permitted to explain the electronic exchanges between molecule and copper, thus justifying the experimentally obtained inhibition efficiency values. A local reactivity study of molecules indicated that N (29) and C (7) atoms are the likely sites for nucleophilic and electrophilic attacks, respectively. In addition, QSPR model was used to correlate experimental inhibition efficiency with the descriptor parameters of the studied molecule, and it is found that the calculated inhibition efficiencies are close to experimental inhibition efficiencies. Finally, this study showed a good correlation between theoretical and experimental data.