Pyrazines as Potential Corrosion Inhibitors for Industrial Metals and Alloys: A Review

Pyrazine is an important diazine with the nitrogen atoms occupying the 1,4-positions within an aromatic ring. Pyrazine and its derivatives find great importance in food and medicine courtesy of their chemical characteristics functionality, namely the chemistry of their nitrogen atoms. Based on the known ability of some nitrogen-based compounds to function as excellent corrosion inhibitors for metallic materials in aqueous solutions, pyrazine and its derivatives have been reported as effective corrosion inhibitors. However, these reports are relatively scarce and limited. Herein, we have attempted a review of the known literature investigating the corrosion inhibition properties of pyrazine and its derivatives. They were reported to function as mixed-type inhibitors for steel and Al and Mg alloys. Their adsorption follows the Langmuir isotherm with steel and deviated in the case of Al and Mg alloys. The adsorption of the pyrazine derivatives on steel may be physical or chemical but is purely chemical on Al and Mg alloys. Theoretical correlations with molecular dynamic simulation have also been reviewed. We have also provided future considerations and direction of research on this important multifunctional chemistry.