The effect of (E)-4-methoxy-N-(methoxybenzylidene)aniline (P1) and (E)-N-(4-methoxybenzylidene) -4-nitroaniline (P2) on the corrosion of steel in molar hydrochloric acid studied by weight loss and electrochemical polarisation. The results obtained reveal that the compounds reduce the corrosion rate. The inhibition efficiency increases with the increase of inhibitor concentration. Potentiodynamic polarisation studies clearly reveal that the presence of the inhibitors does not change the mechanism of the hydrogen evolution reaction and acts essentially as mixed inhibitors. We note good agreement between gravimetric and electrochemical methods. The influence of temperature and inhibitor concentration on the corrosion of mild steel has also been investigated in the temperature range 308-353K, indicates that inhibition efficiency remains almost constant with temperature. The adsorption of the inhibitors on the mild steel surface in both acids obeys the Langmuir' adsorption isotherm. The thermodynamic parameters of adsorption deduced reveal a strong interaction and spontaneous adsorption of P1 and P2 on the mild steel surface. Also the objective of this work is to attempt to find relationships between their molecular and electronic structures and inhibition efficiency. The structural parameters, such as the frontier molecular orbital energies (E_HOMO and E_LUMO), gap of energy ΔE, the charge distribution, the absolute hardness η and the softness σ, the fraction of electrons ΔN transferred from the molecules to iron as well as electronic parameters such as Mulliken atomic populations and Fukui indices were calculated and discussed. © 2014 The Authors.

Title

International Journal of Electrochemical Science

Publisher

Electrochemical Science Group

Publisher Country

Serbia

Indexing

Thomson Reuters

Impact Factor

1.369

Publication Type

Prtinted only

Volume

9

Year

2014

Pages

5328-5351