Organic molecules showing the characteristics of localised corrosion aggravation and inhibition

The behaviour of imidazoline and an acid functionalised resorcinarene as steel corrosion inhibitors in carbon dioxide (CO2)-saturated brine solutions has been studied using an electrochemically integrated multi-electrode array namely the wire beam electrode (WBE). Both imidazoline and resorcinarene acid provided excellent inhibition to general CO2 corrosion; however imidazoline was found to aggravate localised corrosion by creating a small number of major anodes that focused on a small area of the WBE surface, leading to highly concentrated anodic dissolution. The resorcinarene acid showed distinctively different behaviour by generating a large number of minor anodes randomly distributing over the WBE surface, leading to insignificant general anodic dissolution. These results indicate that resorcinarene acid provided effective localised corrosion inhibition by promoting a random distribution of insignificant anodic currents.

Research highlights
► Novel experiment for the discovery of localised corrosion inhibitors.
► New method of identifying inhibitors promoting random distribution of anodic currents.
► Discovery of resorcinarene acid as an effective localised corrosion inhibitor.