Synthesis and Performance of an Enhanced Double Mannich Acidification Corrosion Inhibitor

Ethylenediamine double Mannich base hydrochloride was synthesized from ethylenediamine, paraformaldehyde and acetophenone by Mannich reaction. 2-(hydroxymethyl)-1-phenylprop-2-en-1-one (BAA) and 3-Hydroxypropiophenone were prepared. The structures of above three corrosion inhibitors were characterized by NMR hydrogen spectroscopy, and an enhanced acidified corrosion inhibitor was obtained by compounding these inhibitors. Static weightlessness method, electrochemical method and SEM observation were used to study the inhibition performance of the compound inhibitor on N80 steel in 15% HCl solution. The results showed that the addition of 0.1% compound corrosion inhibitor to 90 ℃, 15% HCl solution, the corrosion rate of N80 steel sheet was 2.316 2 g·m^-2·h^-1, which reacheed the first-level standard (SY/T 5405-1996). In addition, the inhibitor was a mixed inhibitor, and its adsorption on the surface of N80 steel sheet conformed to the law of Langmuir isotherm adsorption. Surface analysis experiments (SEM and EDS) verified that the corrosion inhibitor molecules formed a protective film on the surface of the N80 steel sheet.