Corrosion inhibitors: Correlation between chemical structure and efficiency

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Abstract

Corrosion inhibition efficiencies of heterocyclic, aromatic or partially saturated aromatic compounds (pyrimidines, benzothiazole derivatives, amino-acids containing an aromatic part, pyridines and quinolines) were correlated with quantum Chemical indices of the respective molecules. Inhibition efficiencies measured in acidic solutions containing 0.001 and 0.01 mol/L of the inhibitor, respectively, were collected. The quantum chemical calculations were done by using the simple Hückel method. Comparison of inhibition efficiencies and the differences between energies of the highest occupied and the lowest unoccupied molecular orbitals (A) indicated that if A is lower than 1.3 (in beta units) than the compound will not be active, whereas if Δ > 1.3 beta, the compound may be efficient in 0.001 mole/L concentration. The critical value of A may be lower in solution with 0.01 mole/L inhibitor concentration. Although A alone is not sufficient to account for the variation in the experimental inhibition efficiencies, the present result indicates that compounds which may be easily excited will be inefficient inhibitors because they may be altered or decomposed after the excitation takes place.

Original languageEnglish
JournalNACE - International Corrosion Conference Series
Volume1999-April
Publication statusPublished - Jan 1 1999
EventCorrosion 1999 - San Antonio, United States
Duration: Apr 25 1999Apr 30 1999

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Keywords

  • Amino-acids
  • Aromatic systems
  • Benzothiazole derivatives
  • Corrosion inhibitors
  • Pyridines
  • Pyrimidines
  • Quantum chemistry
  • Quinolines

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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