Synthesis and evaluation of hexamethylenetetramine quaternary ammonium salt as corrosion inhibitor

Abstract A novel corrosion inhibitor, hexamethylenetetramine quaternary ammonium salt, is synthesized using hexamethylenetetramine (HMTA) and bromohexane as main reactants. The inhibitive action of HQAS on QT800‐2 steel in hydrochloric acid medium is evaluated by weight‐loss method, electrochemical method, and quantum chemical calculation. The obtained results show that the efficiency of 0.5 wt% HQAS inhibitor in 30 wt.% HCl solution at 363 K is 92.95% and HQAS can form an excellent synergistic effect with some additives. Polarization curves reveal that HQAS behaves as a mixed‐type inhibitor with dominant anodic inhibition. Furthermore, the theoretical calculation verifies the relationship between the HQAS molecular structure and corrosion inhibition properties.