Mild Steel Corrosion in Gasoline Blends with Acetone–Butanol–Ethanol and Inhibition Efficiencies of Amines

This study investigated the corrosion behavior of mild steel exposed to ABE–gasoline blends (ABE-GBs). Electrochemical methods and static immersion tests were used to determine the corrosion current densities, polarization resistance, and corrosion rates. The results showed that pure ABE-GBs did not compromise the compatibility of mild steel. The material exhibited good passivation, with corrosion current densities remaining below 0.01 μA·cm^–2. In contrast, contamination of ABE-GBs led to a significant increase in corrosion activity, with current densities reaching up to 2.89 μA·cm^–2. Immersion tests confirmed high corrosion rates in these contaminated blends, with values up to 30.4 μm/year. Furthermore, the presence of ABE reduced the inhibition efficiency of amines. At 100 mg/L, only diethylenetriamine (DETA) and triethylenetetramine (TETA) maintained an efficiency above 95%. However, even these inhibitors may lose effectiveness in contaminated blends with higher ABE content over time. Overall, contaminated ABE-GBs can be more aggressive toward mild steel than ethanol- or butanol-based gasoline blends.