Electrochemical and theoretical studies of novel synthesized benzimidazole derivatives as corrosion inhibitors for carbon steel in 1 m hcl

초록

New corrosion inhibitors of benzimidazole derivatives, namely, 6-methoxy-2-(((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)sulfinyl)-1-vinyl-1H-benzo[d]imidazole (EMSB), 6-Methoxy-2-(((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)) sulfinyl)-1-(prop-2-yn-1-yl)-1H benzimidazole (MSVB) and 6-methoxy-2-(((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)sulfinyl)-1-(phenacyl)-1-Hbenzimidazole (MSBP), have been synthesized. Their inhibiting action on the carbon steel corrosion in an acidic medium (1 M HCl) has been investigated by various corrosion monitoring techniques, such as weight loss measurement, potentiodynamic polarization, adsorption, electrochemical impedance spectroscopy (EIS) and basic computational calculations. The results of the investigation show that the inhibition efficiency of all the three inhibitors increases with higher inhibitors concentration, and decreases with a rise in temperature. The inhibitors, MSBP, MSVP and EMSB, show a corrosion inhibition efficiency of 98, 97 and 93%, respectively (dosage of 1x10-3 M). EIS measurements showed an increase in the transfer resistance with the inhibitors concentration. Polarization studies showed that the studied inhibitors are of the mixed type in nature. The adsorption of benzimidazole is described by the Langmuir isotherm. In addition, density functional theory (DFT), calculations and Molecular Dynamics simulations (MD) were undertaken to describe the electronic and adsorption properties of the synthesized inhibitors, including the synergistic/dispersive interactive effects of the multiple adsorptions of the various active constituents in the inhibitor film. Also, DFT and MD simulations were employed to support the experimental findings. © 2021, Sociedade Portuguesa de Electroquimica. All rights reserved.

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