Effect of the inhibitor structure on the corrosion and hydrogen permeation of iron

M.L. RODRÍGUEZ; R. RÉQUIZ AND H. NG; G. JORGE

ANTI-CORROSION METHODS AND MATERIALS

EMERALD GROUP PUBLISHING LIMITED

Año: 2007 vol. 54 p. 93 - 98

0003-5599

Purpose - To investigate the relationship between the 3D molecular structure of two non-planar amines (tribenzylamine - TBA, and N,Ndibenzylaniline - DBA) and their corrosion and hydrogen perrneation inhibition efficiencies for iron in H2S04 solution.Design/methodology/approach - Potentiodynamic polarization and bipolar hydrogen permeation techniques were used to evaluate the inhibitionefficiencies of the investigated amines, which were selected according to their structural differences, which were limited to only one substituent. As aresult, a simplified 3D model was used to correlate the molecular structures with the experimental results.Findings - 8oth amines are good cathodic corrosion inhibitors; however. the DBA displays low hydrogen permeation inhibition efficiency, in contrast tothe TBA. These efficiencies can be ascribed to the sole structural difference between the compounds, which determines their spatial geometry in theadsorbed states.Research limitations/implications - lt may be difticult to find non-planar organic inhibitors for iron in acidic solutions with the desired structuraldifferences and a suitable solubility for further investigations.Originality/value - The proposed approach allows a systematic analysis and an unambiguous correlation between the molecular structure and theprotectiveness of prospective organic inhibitors