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

Abstract

PurposeTo investigate the relationship between the 3D molecular structure of two non‐planar amines (tribenzylamine – TBA, and N,N‐dibenzylaniline – DBA) and their corrosion and hydrogen permeation inhibition efficiencies for iron in H2SO4 solution.Design/methodology/approachPotentiodynamic polarization and bipolar hydrogen permeation techniques were used to evaluate the inhibition efficiencies of the investigated amines, which were selected according to their structural differences, which were limited to only one substituent. As a result, a simplified 3D model was used to correlate the molecular structures with the experimental results.FindingsBoth amines are good cathodic corrosion inhibitors; however, the DBA displays low hydrogen permeation inhibition efficiency, in contrast to the TBA. These efficiencies can be ascribed to the sole structural difference between the compounds, which determines their spatial geometry in the adsorbed states.Research limitations/implicationsIt may be difficult to find non‐planar organic inhibitors for iron in acidic solutions with the desired structural differences and a suitable solubility for further investigations.Originality/valueThe proposed approach allows a systematic analysis and an unambiguous correlation between the molecular structure and the protectiveness of prospective organic inhibitors.

Evaluation of the Electrochemical Impedance Measurement of Mild Steel Corrosion in an Acidic Medium, in the Presence of Quaternary Ammonium Bromides

“…Organic compounds are often used as inhibitors [1][2][3] in acidic media, but their wide application requires designing additional substances with effective protective properties. This process is based on the correlation between the molecular structure of the organic compounds and their inhibiting properties [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The substances of the quaternary ammonium salts group [18][19][20][21] show good inhibitive properties in acidic media.…”