Corrosion inhibition of imidazoline group on Q235 steel in ethanol gasoline blends: Experimental and computational studies

The corrosion inhibition properties of imidazoline compounds, namely 2-phenylimidazoline (PI), 2-undecylimidazoline (UI), and imidazoline oleate (OI), on Q235 steel in ethanol-gasoline blends (EGBs) were systematically investigated. The effectiveness of these inhibitors was evaluated using macroscopic morphology analysis and electrochemical techniques. Surface characterization was conducted via SEM, AFM, and XPS. Additionally, the corrosion inhibition mechanism of imidazoline molecules on Q235 steel was elucidated through theoretical simulations. The results indicate that imidazoline inhibitors primarily functions by suppressing the anodic reaction, with the process being controlled by charge transfer. At the concentration of PI, UI and OI is 5 × 10 −3  Mol·L −1 , the inhibition efficiency exceeding 90 %. These inhibitors form chemical bonds with the Q235 steel surface, creating an adsorption layer centered around the imidazole heterocyclic ring. PI and OI are adsorbed in parallel, whereas UI is adsorbed vertically to play their anti-corrosion role. Imidazoline compounds are effective corrosion inhibitors that can significantly prevent the corrosion of Q235 steel in ethanol-gasoline blends