In order to prevent the metallic equipment from getting severely corroded by the strong acid, corrosion inhibitors are widely used in acidizing engineering and new inhibitors which shows better protective performance are still in great demand. Among the numerous acidizing inhibitors, quaternary heterocyclic ammonium such as N-alkyl quinolinium or pyridinium salts has been applied as the main component of the commercially available inhibitors for decades.<br/>However, in our recent work it is unexpected to notice that a sort of dimer derivative of the quaternary quinolinium would behave a high-effective corrosion inhibition to the steel in strong acid medium. The special dimer derivative could be classified as the ‘indolizine dimer derivative’ due to the presence of the indolizine structure. The derivative can be obtained easily from the corresponding inhibitive quinolinium via an intermolecular 1,3-dipolar cycloaddition process. Surprisingly, the indolizine dimer derivatives could reduce the corrosion rate more apparently at a much lower concentration compared with the precursor quinolinium salts.<br/>In this paper, three quaternary quinoline salts (BQBr, EAQBr, BuQBr) and the related indolizine dimer derivatives (Di-BQBr, Di-EAQBr, Di-BuQBr) was synthesized, purified and characterized successfully. The inhibition performance of the quinoline salts and their derivatives for N80 steel in 15 wt.% HCl was evaluated by weight loss measurement etc. The results of evaluation test confirmed the great difference of corrosion protection ability between the indolizine derivative and the precursor quinolinium salts.

Indolizine Dimer Derivatives: Novel high-effective corrosion inhibitor for acidizing in petroleum engineering

2019 Spring National Meeting

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