Corrosion Inhibitors:  Design, Performance, and Computer Simulations

Abstract

The development of a methodology to predict the performance of a corrosion inhibitor (CI) using specific types of modeled and experimental surfaces and their subsequent estimation is presented. For previously reported imidazoline CIs, the theoretical partition coefficients and molecular volumes were calculated, providing a guide for molecular engineering of new imidazolines. The new CIs, N-[2-(2-alkyl-4,5-dihydroimidazol-1-yl)ethyl]alkylamides and N-[2-(2-alkyloylaminoethylamino)ethyl]alkylamides, were designed, prepared, and their theoretical partition coefficients and molecular volumes calculated. These indexes were correlated between tested and prototype CIs to select the best ones for the corrosion inhibition tests. The inhibition efficiencies were measured through potentiodynamic polarization curves (PPC), linear polarization resistance (LPR), and weight loss measurements (WLM) for SAE-1010 and SAE-1018 steels. The leading molecules were 1-(2-decylaminoethyl)-2-decylimidazoline and 1-(2-dodecylaminoethyl)-2-dodecylimidazoline with WLM efficiencies (steel 1010), of 62.8 and 78.9%, respectively. The efficiencies for the PPC/LPR tests (steel 1018) were 97 and 94%. To understand the mechanism of action of CIs, a simple model is suggested for the growth of self-assembled monolayers of CIs on a crystalline substrate. This model takes into account the amphiphilic nature of the inhibitor molecule on the adsorption process. Despite the simplicity of the model, the Monte Carlo simulations reproduce qualitatively many of the experimentally observed features involved in the formation of monolayers and provide a tentative explanation for the mechanism of corrosion inhibition.

A Bis(di‐n‐butyltin)–Quinone Derivative as a Simultaneous Chemo‐ and Bioactive Corrosion Inhibitor

“…[15] The inhibition efficiencies of this new di-n-butyltin compound are in the order of those found for the tin phthalocyanines previously reported;…”

Understanding corrosion inhibition mechanisms—experimental and theoretical approach

“…Others include charge densities, electronic energies, dipole moments, molecular surface area etc. [15][16][17][18][19][20][21][22][23][24] The electronic structures of the interacting species in this study (i.e. Phe, Met and Fe) are shown in Fig.…”

“…[10][11][12][13][14][15][16][17][18][19][20] Recently, attention has focused on modeling the interaction of inhibitor molecules with metal surfaces and computing the interaction energies, taking cognizance of both covalent and non-covalent contributions to the interaction energy. [20][21][22][23][24] Such an approach offers the added advantage of providing important physical insights on corrosion inhibition mechanisms. The ability to process and investigate materials at the nanoscale makes for better understanding of fundamental physicochemical properties, which can provide vital insights into the mechanisms of metal corrosion and protection, particularly since variations in particle size and metal microstructure determine the rate of diffusion of both the corrodent and inhibitor species through the lattice.…”

Electrochemical Investigation of Corrosion on AISI 316 Stainless Steel and AISI 1010 Carbon Steel: Study of the Behaviour of Imidazole and Benzimidazole as Corrosion Inhibitors

“…The authors found that Dodigen had an efficiency ranging from 74% to 98%, depending on the concentration used. Other investigations using computer simulations of new imidazole derivatives showed that these compounds possess the ability to inhibit the corrosion process on AISI 1010 carbon steel, which showed 62.8% inhibition efficiency [25].…”