Water-Dispersible Corrosion Inhibitor Derived from Greenhouse Gas

Abstract Imidazolines have very good corrosion inhibition properties, but many have limited solubility or dispersibility in water. For this study, a novel method for increasing dispersibility of imidazolines was developed by incorporating molecules derived from recycled greenhouse gas such as propylene carbonate (PC). The reaction of imidazoline and PC proceeds to completion under relatively mild conditions to produce an imidazoline-PC adduct (IMPCA) without producing byproducts and requiring no purification. IMPCA remained oil soluble while also being easily dispersed in water. The corrosion inhibition properties of IMPCA were tested and compared against the parent compound in different kinds of brines. Performance testing was done in CO2-saturated brine with hexane as an organic layer. Organic acid, hydrogen sulfide and minerals are varied in the setup. In one setup, low amounts of organic acid were present. The corrosion inhibition observed with 15 ppm IMPCA was 92.5% compared to 91.1% for the parent imidazoline compound. When higher organic acid was present, the corrosion inhibition of IMPCA was 79.9% compared to 89.9 % for the parent imidazoline. In another set-up, when high calcium level was added, the corrosion inhibition of 10 ppm IMPCA was 76.2% while that of parent imidazoline was 69.9%. The IMPCA was also tested against other water-soluble imidazoline inhibitors and found to have comparable corrosion protection. Corrosion testing showed that in some brines, the activity was maintained while in others, the activity was enhanced. Clearly, the utility IMPCA were enhanced because of improved dispersibility in aqueous medium. This new product utilized a new carbon-dioxide derived starting material to increase the water dispersibility of imidazolines while improving their corrosion inhibition properties.