The inhibition performance of hydroxy lauric imidazoline for mild steel in chloride solution saturated with CO₂

Abstract

In the paper, a novel hydroxy lauric imidazoline (HL-IM) was synthesized using lauric acid and ethylene diamine as raw materials. Methanol reaction method was introduced to prepare the hydroxy lauric imidazoline (HL-IM). According to the results of experiments, the optimum synthesis conditions of methanol reaction was determined through orthogonal experiment, which were: methyl laurate: ethylene diamine = 1: 1, sodium methoxide (0.75 wt %), reaction temperature 100°C, reaction time 2 h. The inhibition efficiency of HL-IM inhibitor was investigated in the condition of 5 wt % NaCl solutions saturated with CO₂ at 333.15 K for 72 h. With 150 mg L^–1 inhibitor dosage, the efficiency of inhibition reached 90.17% by weight loss method. Through film-forming property, foaming characteristic, and emulsification tendency test, it w a s shown that HL-IM had good water-solubility, a smaller emulsification tendency in 5 wt % NaCl solution, and a little foaming performance. Meanwhile, referring to the polarization curves tests, the synergistic effect of HL-IM with the potassium iodide, methylbutynol, and cetyltrimethyl ammonium bromide was studied.