Synthesis and Property Evaluation of Urotropine Quaternary Ammonium Salt as a Corrosion Inhibitor

Urotropine quaternary ammonium salt was synthesized as a corrosion inhibitor using urotropine and linear halogenated hydrocarbon as main reactants, methanol as a solvent. Synthetic conditions were optimized through single factor tests, in which static corrosion rate was adopted as an evaluation index. The results show that carbon chain length of 6 in halogenated hydrocarbon, molar ratio of urotropine to halogenated hydrocarbon of 1:1.5, reaction temperature of 50℃ and reaction time of 7 hours were considered as the optimal synthetic conditions. When 0.5% (mass fraction) urotropine quaternary ammonium salt was added into 15% (mass fraction) HCl solution at 90℃, the corrosion rate of QT-800 steel decreased form 236.334 6 g·m^-2·h^-1 to 3.760 6 g·m^-2·h^-1. The urotropine quaternary ammonium salt was a mixed type corrosion inhibitor but mainly for suppressing anodic reaction. The synthetic corrosion inhibitor molecules could adsorb on the surface of QT-800 steel to suppress pitting corrosion.