Corrosion study of iron using piperazine derivatives as inhibitors
Williams, Charles William
Master of Arts
The corrosion of iron by HC1 using cyclic polyethyleneimines as inhibitors has been done many times. Piperidine, a cyclic six membered ring CH.NH has attracted the most attention as an inhibitor because of the high basicity and lack of strain on the bonds in the ring. Piperazine, a cyclic six membered ring CHNH, has not been studied as a corrosion inhibitor. This poor base and some of its simple derivatives were chosen to study as inhibitors because of the possibility of dual adsorption through both nitrogen sites. It was concluded that the piperazine derivatives adsorbed vertically to electrode surface with small concentrations (less than 5mM) of inhibitor while at higher concentrations (greater than 25mM) adsorption was horizontal (i.e. through both nitrogen sites). Inhibitor efficiency was directly related to molecular coverage, stability of the ammonium cation and, to a lesser extent, the basicity of the inhibitor studied. A new method was used to calculate corrosion rates but proved ineffective in interpreting individual electrode behavior.