Theoretical and experimental studies of structure and inhibition efficiency of imidazoline derivatives

The purpose of this paper is to provide information on the electron configuration of several imidazoline inhibitors by the quantum chemical calculation and to seek correlation between molecular structure and behavior of corrosion inhibition. Three imidazoline derivatives with different electron-releasing substituents were designed by quantum chemical study. On the basis of calculated results, the inhibition efficiency is predicted as in following order: compound III>II>I. These compounds were synthesized and measured by weight loss and electrochemical methods. Theoretical prediction is in good agreement with experimental results. Based on the theoretical and experimental results, it is concluded that electron donor group introduced, particularly, the substituent group with conjugated system, to imidazoline ring will improve corrosion inhibition efficiency of imidazoline derivatives. (C) 1999 Elsevier Science Ltd. All rights reserved.