Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (03): 525-531.doi: 10.3866/PKU.WHXB20090321

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Effect of Molecular Structure of Imidazoline Inhibitors on Growth and Decay Laws of Films Formed on Q235 Steel

 ZHANG Jing, DU Min, YU Hui-Hua, WANG Ning   

  1. Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, Shandong Province, P. R. China
  • Received:2008-10-29 Revised:2008-12-19 Published:2009-03-02
  • Contact: ZHANG Jing


Inhibition performance as well as the growth and decay laws of films formed on Q235 steel in a saturated carbon dioxide salt solution of imidazoline and imidazoline with a thioureido group were investigated by polarization curve and electrochemical impedance spectroscopy (EIS) techniques. Results showed that both types of imidazoline derivative inhibitors were mix-type inhibitors which mainly inhibited anodic processes. At 85 ℃, the film formed in 40 mg·L -1 of the non-thioureido imidazoline inhibitor formed slowly and had poorer adsorption capability than the thioureido-containing imidazoline inhibitor. The non-thioureido imidazoline inhibitor also disrobed easily from the steel. The film of thioureido-containing imidazoline can auto-repair itself. It also had better adsorption and inhibition efficiency compared with the non-thioureido imidazoline inhibitor. The hydrolyzed imidazoline with a thioureido group has poor absorption capability and its film life and inhibition efficiency decreased compared with the thioureido-containing imidazoline inhibitor. In this paper electrochemical results are also explained using quantum chemistry analysis.

Key words: Molecular structure, Imidazoline inhibitor membrane, Polarization curve, Electrochemical impedance spectroscopy, Quantumchemistry


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