2-(4-fluorobenzyl)Chromeno[2,3-c]Pyrozol-3(2H)-One as Copper Corrosion Inhibitor in HNO3: Gravimetric and Quantum Chemical Investigation Methods

The use of organic compounds as corrosion inhibitors has become a principal means of protecting metal equipment in industrial applications. This work therefore set out to evaluate the inhibiting properties of 2-(4-fluorobenzyl)chromeno[2,3-c] pyrozol-3(2H)-one for copper corrosion in 1M nitric acid solution. These properties were investigated using gravimetric method and quantum chemical calculations. Inhibition efficiency increased with temperature, inhibitor concentration and immersion time. Adsorption of this molecule on copper surface occurs according to Langmuir isotherm, while the thermodynamic parameters of absorption and kinetics prove that adsorption is spontaneous and dominated by chemisorption. Quantum chemical parameters derived from density functional theory (DFT) revealed that there is a strong interaction based on electronic exchange between the inhibitor and copper. Global and local reactivity parameters such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy, energy gap, Fukui functions and dual descriptor were used to understand the molecule-metal interface and to design more appropriate organic corrosion inhibitors. Theoretical results proved to be consistent with the experimental data obtained.