Synthesis and Performance Evaluation of an Imidazoline Inhibitor

An imidazoline inhibitor was synthesized from oleic acid and diethylenetriamine as reactants, and triethylenetetramine as water carrying agent. The influences of inhibitor concentration, synthesis temperature and reaction time on corrosion inhibition performance were studied by orthogonal experiment and weight loss method. The molecular structure and corrosion inhibiting performance were studied by infrared spectrum, weight loss testing, electrochemiscal measurement and SEM. Results indicate that the optimized parameters for the synthesis are as follows: the ratio of oleic acid to triethylenetetramine is 1.0:3.1, synthesis temperature is 190℃, reacting time is 7h. Under the optimal synthetic reaction conditions, the corrosion inhibition efficiency of the prepared inhibitor is over 90%. The optimized temperature and concentration for using this inhibitor are below 60℃ and 300mg/L, respectively, at this concentration the corrosion inhibition efficiency is over 93%. The electrochemiscal polarization curves show that the inhibitor can be classified as a mixed type corrosion inhibitor. SEM indicated that the inhibitor prevented corrosion reaction and blocked the growth of the corrosion product.