Theoretical prediction and experimental study of 1-Butyl-2-(4-methylphenyl)benzimidazole as a novel corrosion inhibitor for mild steel in hydrochloric acid

• Theoretically predicted the inhibition performance of BMPB and BI.
• Experimentally validated that the inhibition performance of BMPB is better than BI.
• The inhibitor, BMPB, shows good inhibitive properties for mild steel in HCl.
• The adsorption process accords with the Langmuir adsorption model.

The inhibition performance of a newly synthesized benzimidazole derivative, 1-Butyl-2-(4-methylphenyl)benzimidazole (BMPB), on the surface of mild steel in 1.0 M HCl was predicted theoretically using molecular dynamics method and quantum chemical calculations in comparison with benzimidazole (BI) compound. The theoretical results confirmed by electrochemical measurements and scanning electron microscopy study show that BMPB may exhibit better inhibitive performance than BI for mild steel in hydrochloric acid solution. The adsorption process and thermodynamic parameters of BMPB were calculated and discussed. It was found that BMPB is classified as a mixed type inhibitor, suppressing both anodic metal dissolution and cathodic hydrogen evolution reactions. The high inhibitory efficiency of BMPB is due to the formation of a protective film on the mild steel surface. This study shows that theoretical calculations can be used as a reliable method to select organic inhibitors prior to experiments.