Determination of inhibition effects of various imidazole derivatives on copper corrosion in 0.1M HCl media

In the present study the inhibitive behaviour of 1H-imidazole, 1-methyl imidazole, imidazolidin-2-one, 4-(imidazole-1-yl) acetophenone, 4-(imidazole-1-yl) phenol and L-hystidine on the corrosion of copper in 0 center dot 1 M HCl has been investigated by potentiodynamic polarisation and polarisation resistance techniques. Except for 2-imidazolidone, the tested imidazole derivatives were found to behave as cathodic inhibitors. 1-methyl imidazole, 4-(imidazole-1-yl) acetophenone, 4-(imidazole-1-yl) phenol and L-hystidine were adsorbed on copper surface according to Temkin isotherm model. By using semi-empirical quantum chemical methods, physical parameters such as charge on the heteroatoms of imidazole derivatives q(n), energies of highest occupied molecular orbital ( HOMO) and lowest unoccupied molecular orbital (LUMO) and dipole moments were calculated. Possible correlations between these calculated physical parameters and inhibitor efficiencies were considered. Finally, the mechanistic information relating to the inhibition process was elucidated.