Synthesis and Performance Evaluation of Hydrochloric Acid Acidification Corrosion Inhibitor

Corrosion rate as evaluation index,the optimum reaction condition of the Mannich base corrosion inhibitors was obtained as follows: cyclohexylamine,formaldehyde,acetophenone in molar ratio 1∶2∶1,90℃ reaction temperature,8 hrs reaction time,and 4 pH value.The hydrochloric acid acidification corrosion inhibitor was composed of the Mannich base synthesized,2.5% peregal and methanol.The corrosion inhibition was studied by the methods of weight-loss and electrochemical.The results showed that corrosion rate of N80 steel piece in 15% technical hydrochloric acid decreased with increasing dosage of corrosion inhibitor at 90℃,increased with increasing concentration of hydrochloric acid,and increased with increasing temperature.The corrosion rate was of 3.635 g/(m2·h) with dosage of corrosion inhibitor 1.0% at 90℃,which satisfied the standard.The results of polarization curves test indicated that the corrosion inhibitor mainly controlled cathodic processes and the mechanism was mainly geometrical overlay effect.