Synthesis and evaluation of corrosion inhibitory and adsorptive properties of N-(β-ethoxypropionitrile-N,N-bis(2-hydroxyethylethoxy) fatty amide.

Gulmira Rakhymbay,Khaisa Avchukir,Mirgul Turmukhanova,Yeldana Bakhytzhan,Florence Vacandio,Raigul Jumanova,Adewale Adeloye,Bibisara Burkitbayeva,Akmaral Argimbayeva

doi:10.1098/rsos.211066

Abstract

The present study reports a synthetic condensation process of a vegetable oil (waste) reacted with triethanolamine, maleic anhydride and acrylonitrile in (1 : 1.2 : 2 : 1) mole ratios to obtain N-(β-ethoxypropionitrile)-N,N-bis(2-hydroxyethylethoxy) fatty amide as a major inhibitory product. Corrosion property of steel in a 3% NaCl solution in the presence of a potential inhibitor was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. These methods gave consistent results, from which it is noticeable that inhibition efficiency increases with the increasing concentration of the inhibitor. Gravimetric studies show an increase in the sample mass at an inhibitor concentration of 10 mM, indicative of adsorbed film formation on the surface. The polarization curve results showed that the compound demonstrates itself as an anodic-type inhibitor. A rise in polarization resistance values in the EIS measurements also confirmed that the compound acts as an effective inhibitor of steel corrosion. Furthermore, the R(CR)(QR) equivalent circuit was used to interpret the results obtained in the investigation of the corrosion behaviour of steel in solution with an inhibitor. The standard adsorption free energies calculated from the Langmuir isotherm indicate that adsorption takes place by physical and chemical mechanisms. The presence of adsorbed protective film was confirmed by FT-IR spectrum and SEM micrographs.

Highlights

High mechanical strength and low cost are important characteristics that ensure widespread use of metallic materials in the marine environment, in production, processing, transportation and construction of underground pipelines, fuel tanks and heat exchangers [1,2,3,4,5]
The results obtained from the study of corrosion of samples in 3.0% NaCl in the absence or presence of inhibitor at various concentrations is as shown in table 1
The results presented in figure 2 show that the addition of inhibitor in 3.0% NaCl corrosive medium shifts the corrosion potential (Ecorr) toward more electropositive values and significantly reduces current density, especially the inhibitive effect is pronounced at high concentrations of the inhibitor

Summary

Introduction

High mechanical strength and low cost are important characteristics that ensure widespread use of metallic materials in the marine environment, in production, processing, transportation and construction of underground pipelines, fuel tanks and heat exchangers [1,2,3,4,5]. The high content of aggressive sodium chloride in marine water contributes to a decrease in the corrosion resistance, strength and workability of many metals and alloys. There are many works that have been devoted to the use of effective heterocyclic and/or heteroatomic containing organic compounds that improve the anticorrosion properties of steel in sodium chloride solution. The presence of heteroatoms in particular the (O, S, N, P), aromatic rings and multiple bonds with π-electrons in these inhibitors contribute significantly to the formation of passive barriers on metal surface, thereby blocking the active sites of corrosion [1,11,12,13,14,15,16]. Reports have shown that not all of the proposed inhibitors are environmentally friendly and cost-effective

Methods

Results

Conclusion