Synthesis of Composite Corrosion Inhibitor Based on Maleic Anhydride, Monoethanolamine and Phosphate Acid

Abstract

In this article, the optimum conditions for the synthesis of corrosion inhibitors based on maleic anhydride, monoethanolamine, and phosphoric acid and the inhibitory efficiency of the obtained inhibitor are studied. In this case, the mole ratio of the starting materials was 2 moles (122 g) of monoethanolamine: 1 mole (98 g) of maleic anhydride: 1 mole (98 g) of phosphoric acid, and the yield of the reaction was 92.5%. The IR spectra of the structure of this obtained inhibitor were studied. The inhibition efficiency of this corrosion inhibitor was measured by the gravimetric method according to GOST 9.506-87 in 1M HCl + 200 mg/l NaCl and 0.5 HCl + 200 mg/l NaCl environments. The inhibition efficiency was 93.15% and 92.86%, respectively. reached According to the results of the electrochemical research, the inhibition efficiency was 91.5%. In addition, Langmuir, Frumkin, and Tyomkin isotherms of the inhibition mechanism of the inhibitor were studied. The effect of the inhibitor on the steel surface was studied with a scanning electron microscope.