Synthesis and Property Evaluation of Quinoline Diquaternary Ammonium Salt as Acidification Corrosion Inhibitor

Three diquaternary ammonium salts as acidification corrosion inhibitors named 1,4-butane-bis-(quinoidine bromide) (Q-4-Q),1,6-hexane-bis-(quinoidine bromide) (Q-6-Q) and 1,8-octane-bis-(quinoidine bromide) (Q-8-Q) were prepared by quaternization of quinoline and alkyl halides. The synthesized compounds were characterized using HNMR spectroscopy. Weight loss method,electrochemical method and SEM were used to study the corrosion inhibition properties of those three products for N80 steel in 15% HCl solution. The results showed that Q-8-Q had the best inhibition efficiency,the best synergistic ratio for Q-8-Q and cinnamaldehyde (CA) was cQ-8-Q∶cCA＝1∶1. The inhibition efficiency for N80 steel in 15% HCl solution at 90 ℃ could reach 99.79% at the concentration of 6 mmol/L. A protective film was formed on the surface of N80 steel and confirmed by surface analysis experiments,the synergistic inhibitor was a mixed type inhibitor mainly to inhibit the cathodic reaction,which belonged to the “negative catalytic effect”.