The influence of the chemical structure of 3-mercapto- and 3 sulfinyl derivatives of 5-amino-1H-1,2,4-triazoles on their inhibitory ability against chloride-induced copper corrosion

• A.A. Kruzhilin, D.S. Shevtsov, A.Yu. Potapov, M.Yu. Krysin and Kh.S. Shikhaliev

Voronezh State University, 1 Universitetskaya pl., 394018 Voronezh, Russian Federation

Abstract: The aim of this study is to investigate the anticorrosive properties of 5-amino-1H-1,2,4-triazole derivatives by introducing substituents such as thioacetonitrile and thioacetic acid fragments, as well as their mild oxidation products – sulfinylacetonitrile and sulfinylacetic acid. The synthesis methodology involved a sequence of two transformations: alkylation of 3-mercapto-5-amino-1H-1,2,4-triazole with chloroacetonitrile or monochloroacetic acid followed by the oxidation of the resulting 3-(alkylthio)-5-amino-1H-1,2,4-triazoles. The synthesized inhibitors were identified using high-performance liquid chromatography with high-resolution mass spectrometry detection (HPLC-HRMS-ESI) and UV detection, as well as NMR spectroscopy. Gravimetric and polarization corrosion tests were conducted on M1 copper samples in 1% chloride solutions. The highest inhibitory activity was exhibited by 2-((5-amino-1H-1,2,4-triazol-3-yl)sulfinyl)acetonitrile 3a at a concentration of 0.10 mmol·dm^–3, providing significant protection without compromising the solubility of the inhibitor in aqueous solutions. The results of the study indicate that the introduction of an acetonitrile fragment into the chemical structure of 1,2,4-triazole-class inhibitors leads to a significant increase in their inhibitory efficiency against copper corrosion. Moreover, the application of sulfoxides based on the investigated alkylthiotriazoles results in an additional increase in the protective properties of these compounds, which is most pronounced for 2-((5-amino-1H-1,2,4-triazol-3-yl)sulfinyl)acetonitrile.

Keywords: metal corrosion, copper, corrosion inhibitors, heterocyclic compounds, aminotriazoles, physicochemical research methods

Int. J. Corros. Scale Inhib., 2024, 13, no. 3, 1590-1606
doi: 10.17675/2305-6894-2024-13-3-13

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