Theoretical study using DFT calculations on inhibitory action of four pyridazines on corrosion of copper in nitric acid

Abstract

In this part 3, The inhibitive effect of four substituted pyridazines, 5-[hydroxy(phenyl)methyl]-6-methylpyridazin-3(2H)-one (P1), 4-(2-chlorobenzyl)-6-hydrazino-3-methyl-1,6-dihydro pyridazine (P2), 5-(2,6-dichlorobenzyl)-6-methylpyridazin-3(2H)-one (P3) and 5-[(2-chlorophenyl) (hydroxy)methyl]-6-methyl pyridazin-3(2H)-one (P4) against the copper corrosion in nitric acid solution is investigated using density functional approach B3LYP/6-31G* calculations. Results obtained by weight loss and polarization measurements in part 1 show that P1, P3, and P4 are the best inhibitors. The kinetic and adsorption parameters obtained in part 2 indicated that pyridazine acted preferentially by physical adsorption. The calculated quantum chemical parameters are the highest occupied molecular orbital, the lowest unoccupied molecular orbital, the separation energy, dipole moment, electronegativity, electron affinity, global hardness, softness, ionization potential, the fraction of electrons transferred, and the total energy. The obtained data are discussed according to the inhibition efficiencies obtained.