Corrosion inhibition of brass in phosphoric acid solution by 2-(5-methyl-2-nitro-1H-imidazol-1-yl)ethyl benzoate

Abstract

Abstract A new 2-(5-methyl-2-Nitro-1H-imidazol-1-yl)ethyl benzoate (IMDZ-B) was synthesized and characterized using elemental analyses, NMR and Fourier transform infra-red (FTIR) techniques. Its effect on brass corrosion in 1.0 M H3PO4 solution was investigated by using electrochemical measurements coupled with X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX). The polarization measurements showed that the IMDZ-B acts as a mixed type inhibitor. Indeed, it is found that the IMDZ-B compound is a very good inhibitor, which its inhibition efficiency increases with concentration to reach a maximum of 99.5% at 10−3 M. In addition, the obtained electrochemical parameters from impedance indicated that the IMDZ-B molecules act by adsorption on metallic surface. This adsorption was found to obey Langmuir's adsorption isotherm. However, the temperature effect on the performance of IMDZ-B was also studied. It is found that the IMDZ-B takes its performance at high temperature. In addition, the obtained kinetic and thermodynamic parameters showed that the IMDZ-B molecules act via two adsorption modes, physisorption and chemisorptions, and its process is endothermic and spontaneous. Finally, the XRD and SEM/EDX analyses confirmed the electrochemical obtained results. SEM micrograph of brass surface after 16 h of immersion in 1.0 M H3PO4 solution (a) without and (b) with 10−3 M of IMDZ-B.