Synthesis, Performance and Anti-corrosion Mechanism of a Mannich Base 3-(Diethylamino)-1-Phenylpropan-1-one

A Mannich base, 3-(diethylamino)-1-phenylpropan-1-one(DEAP), which can be used as acidizing corrosion inhibitor, was synthesized with acetophenone, diethylamine and formaldehyde as raw materials at pH from 2 to 3 and then purified, the yield reached 91.4%. The structure of DEAP was characterized by elemental analysis and FT-IR analysis. The anti-corrosion performance of DEAP for N80 steel in 15% hydrochloric acid (HCl) and soil acid (12% hydrochloric acid + 3% hydrofluoric acid) was investigated by static weight loss method. The corrosion inhibition mechanism of DEAP in 15% HCl was studied by polarization curves and scanning electron microscopy, and the adsorption behavior of DEAP on the surface of N80 steel was discussed. The results showed that the anti-corrosion rate reached 99.74% and 99.55%, when the dosages of DEAP were 0.6% and 0.75% in hydrochloric acid and soil acid, respectively. DEAP is a inhibitor of mixed-type. The adsorption process of DEAP on the surface of N80 steel was mainly chemisorption. This process was spontaneous and obeyed Langmuir adsorption isotherm.