Abstract: In this paper, imidazoline (IMTT) was synthesized through amidation and cyclization reactions by using oleic acid, triethylene tetramine as raw material. IMTT, which is reacted with formaldehyde and acetone, is used to prepare mannich base inhibitor (IMTTM). The structure of product was identified by IR. By using dynamic weight loss method, polarization curve method, AC impedance technique (EIS) and SEM-EDS, the corrosion inhibition of number 10 steel in HCl aqueous solution was studied. The results showed that at 60 ℃, the corrosion inhibition rate of IMTT and IMTTM is 96.11% and 97.75%%, respectively, and the effect of IMTTM is more significant. Polarization curve indicated that both IMTT and IMTTM are a mixed corrosion inhibitor of anode. The EIS test results are basically as same as the ones of polarization curve and weight loss method. SEM-EDS study demonstrated that the corrosion products are mainly different valence oxides of Fe, Cr and Mn. In addition, the corrosion product formed by IMTTM is denser, resulting in better corrosion resistance. It is found through simulated isotherm curves that both inhibitor IMTT and IMTTM follow Langmuir isotherm adsorption.

Key words: Mannich, corrosion inhibitor, isothermal adsorption