Heptadecyl-tailed mono- and bis-imidazolines: A study of the newly synthesized compounds on the inhibition of mild steel corrosion in a carbon dioxide-saturated saline medium

Abstract The study compares, for the first time, the corrosion inhibition properties of a diethylenetetramine-derived imidazoline ( I ), and tetraethylenepentamine-derived imidazoline ( II ) and bis-imidazoline ( III ), all having heptadecyl pendants as hydrophobes. The newly synthesized imidazolines show excellent inhibition efficiencies against the corrosion of mild steel in 0.5 M sodium chloride solutions saturated with carbon dioxide. The inhibition efficiencies increased with the increasing temperature. At a concentration of 100 ppm at 40 °C, imidazolines I , II , and III imparted inhibition efficiencies of 84, 95 and 96%, respectively. The imidazolines cover most of the steel surface before their critical molar concentrations are reached.