Mercaptopropionic acid-modified oleic imidazoline as a highly efficient corrosion inhibitor for carbon steel in CO2-saturated formation water

Two imidazoline derivatives (OI and MOI) were synthesized as highly efficient inhibitors, and their inhibition performances and mechanisms in CO2-containing solution were studied using weight loss measurements, electrochemical tests, surface analysis and theoretical calculations. The results indicate that OI and MOI show excellent inhibition efficiency. Especially for MOI, its inhibition efficiency is as high as 95.58% at 20 ppm. Theoretical calculations confirm that both inhibitors successfully adsorb on metal surface via chemisorption. MOI shows a better inhibition performance than OI, because the sulfhydryl in MOI can be used as a powerful adsorption site, effectively improving the adsorption ability of MOI. •A high inhibition efficiency, 95.58%, could be achieved using 20 mg/L MOI.•MOI with multiple adsorption sites interacts with Fe via chemisorption.•The adsorption ability of OI can be increased via the introduction of sulfhydryl.