Open Access Research article

Quantum chemical assessment of benzimidazole derivatives as corrosion inhibitors

Hasan R Obayes1, Ghadah H Alwan2, Abdul Hameed MJ Alobaidy3, Ahmed A Al-Amiery34*, Abdul Amir H Kadhum4 and Abu Bakar Mohamad4

Author Affiliations

1 Applied Chemistry Division, Applied Science Department, University of Technology, Baghdad, Iraq

2 Ministry of Sciences and Technology, Industrial Research & Development Directorate, Industrial Applications Center, Baghdad, Iraq

3 Environmental Research Center, University of Technology (UOT), Baghdad 10001, Iraq

4 Department of Chemical & Process Engineering, Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor 43000, Malaysia

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Chemistry Central Journal 2014, 8:21  doi:10.1186/1752-153X-8-21

Published: 27 March 2014

Abstract

Background

The majority of well-known inhibitors are organic compounds containing multiple bonds and heteroatoms, such as O, N or S, which allow adsorption onto the metal surface. These compounds can adsorb onto the metal surface and block active surface sites, reducing the rate of corrosion.

Results

A comparative theoretical study of three benzimidazole isomers, benzimidazole (BI), 2-methylbenzimidazole (2-CH3-BI), and 2-mercaptobenzimidazole (2-SH-BI), as corrosion inhibitors was performed using density functional theory (DFT) with the B3LYP functional basis set.

Conclusions

Nitro and amino groups were selected for investigation as substituents of the three corrosion inhibitors. Nitration of the corrosion inhibitor molecules led to a decrease in inhibition efficiency, while reduction of the nitro group led to an increase in inhibition efficiency. These aminobenzimidazole isomers represent a significant improvement in the inhibition efficiency of corrosion inhibitor molecules.

Keywords:
Benzimidazole; B3LYP; Corrosion; DFT; Inhibitor