Bis-[(5-amino-1H-1,2,4-triazol-3-yl)mercapto]alkanes - novel twin compounds as copper corrosion inhibitors in high chloride containing media

The article describes an example of application of the twin molecule concept in the molecular design of new organic corrosion inhibitors. We have developed a synthesis method and proved the structure of new bis-[(5-amino-1 H -1,2,4-triazol-3-yl)mercapto]alkanes as a result of the condensation of 3-mercapto-5-amino-1,2,4-triazole with dihaloalkanes. The inhibitory effect of the synthesized substances on copper corrosion in neutral and acidic chloride-containing media was evaluated using direct tests in a salt-spray chamber and weight loss measurements as well as potentiodynamic polarization measurements. It has been established that bis-[(5-amino-1 H -1,2,4-triazol-3-yl)mercapto]alkanes A-C at a concentration of at least 0.10 mmol∙dm-3 show high protective characteristics both in direct tests (from 64 to 192 h in salt spray and from 92 to 99% in 1 wt.% HCl solutions) and in electrochemical tests (from ~30 to ~85% in 10 mM NaCl solutions). Moreover, the degree of protection increases smoothly with an increase in the concentration of the inhibitor, as well as with an increase in the length of the linker hydrocarbon fragment. These developed compounds can be used to protect various heat exchange equipment made of copper or its alloys. They are promising for use in water circulation systems to prevent corrosion and scale formation, as well as to protect copper in the production of conductor materials, to prevent or slow down atmospheric corrosion of structural materials based on copper and its alloys. The developed compounds can be used to protect various heat exchange equipment made of copper or its alloys, are promising for use in water circulation systems to prevent corrosion and scale formation, in the protection of copper in the production of conductor materials, to prevent or slow down atmospheric corrosion of construction materials based on copper and its alloys.