Anti‐corrosive property of bioinspired environmental benign imidazole and isoxazoline heterocyclics: A cumulative studies of experimental and DFT methods

Abstract

In the present study, four imidazoline (IDZ) and four isoxazolines (ISO) heterocyclics differing in the nature of methoxy (-OCH 3 ) and aromatic (phenyl and naphthyl) moieties are synthesized, characterized and evaluated as corrosion inhibitors for mild steel in acidic solution of 1 M HCl. Results showed that imidazoline based heterocyclic compounds are better corrosion inhibitors than isoxazoline based heterocyclics and both classes of compounds showed inhibition efficiency of more than 85% at 20 mgL −1 concentration. Results further showed that inhibitors containing methoxy, phenyl, and naphthyl moieties showed higher protection efficiency as compared to the inhibitors without these moieties. PDP Study revealed that investigated IDZs and ISOs acted as mixed type inhibitors and their adsorption on the metallic surface followed the Langmuir adsorption isotherm model. All the experimental results were corroborated by density function theory (DFT) based quantum chemical calculations. Numerous DFT based indices calculated for neutral as well as protonated forms of the IDZs and ISOs in order to get better insight about metal-IDZs/ISOs interactions. Outcomes of the DFT analysis showed that protonated (cationic) form of the all the inhibitors are more strongly adsorbed on the metallic surface as compared to their neutral form.

Expired Cefalexin Loaded into Mesoporous Nanosilica for Self-Healing Epoxy Coating on 304 Stainless Steel

“…In an acidic environment, the amino groups of the cefalexin are protonated and positively charged and are adsorbed on the 304SS by electrostatic attraction due to the negatively charged chloride ions [ 28 ]. Fe in the 304SS has a greater affinity to coordinate with ligands bearing unshared electron pairs of heteroatoms and hence forms the protective film [ 40 , 41 ]. The cefalexin released from the EP-Cefalexin@MSNs adsorbs on the 304SS through unshared electron pairs in O and S, leading to the formation a protection layer ( Figure 8 d).…”

Glyceral Trinitrate: As Potential Corrosion Protector for Mild Steel in Acid Medium Along with Paint-coated Steel in a Saline Environment

“…Size of mild steel specimens were cut into dimensions 5cm 2 exposed area for gravimetric experiments, Mild steel (Weight%: 0.098% C, 99.653% Fe, 0.02% P, 0.012% Ni, 0.201% Mn, 0.016% S and mild steel rod exposed surface area 1cm 2 where used for electrochemical analysis. For all the experiments the surface of the mild steel samples were polished by using a separate grade (400-1000 grit) of emery papers, then cleaned by using distilled water and dried.…”

“…Mild steel has excellent mechanical properties 1 and due to this property, it is used as the material of construction engineering structural material. In petroleum industries, mild steel is extensively used transmission pipelines, dubler, flow lines, etc., where it is susceptible for oxidative degradation for which different descaling process such as acid well acidification [2][3][4][5] , acid cleaning, petrochemical processes are widely used for cleaning process. Mild steel undergoes corrosion attack, due to aggressive nature [6][7][8] of acidic medium.…”

Bioinspired Heterocyclic Compounds as Corrosion Inhibitors: A Comprehensive Review

“…Besides, they show excellent inhibition efficiency (IE) even when used in low concentrations. [33] Heterocyclic compounds, therefore, owing to their environmentally friendly nature, costeffectiveness, and super inhibition efficiency À a much sought-after combination of features in an inhibitor À are an important and effective class of CIs. However, since the three-or fourmembered heterocycles are considerably less stable than the five-or six-membered heterocycles due to ring strain, they do not constitute the most important classes of heterocyclic corrosion inhibitors (HCIs).…”

“…These compounds can be easily synthesized from readily and commercially available sources. Besides, they show excellent inhibition efficiency (IE) even when used in low concentrations [33] . Heterocyclic compounds, therefore, owing to their environmentally friendly nature, cost‐effectiveness, and super inhibition efficiency − a much sought‐after combination of features in an inhibitor − are an important and effective class of CIs.…”