Schiff' Bases as Corrosion Inhibitor for Aluminum Alloy in Hydrochloric Acid Medium

Abstract

Three Schiff' bases (SB) were synthesized, characterized and evaluated as corrosion inhibitor for aluminum in 1.0 M HCl using chemical (weight loss) and electrochemical (open circuit potential, potentiodynamic polarization, and electrochemical impedance) techniques. The influence of temperature and concentration was investigated. It has been shown that the efficiency of corrosion inhibition increases with the inhibitor concentration and decreases with increasing temperature. The addition of the inhibitor molecules to the corrosive medium shifts the corrosion potential (Ecorr) to the nobler direction. It has been found that the adsorption of the used compounds obeys the Langmuir adsorption isotherm.

Manufacturing of Corrosion Inhibitors and Flow Improvers from Recycling of Waste at Hail City, Saudi Arabia: Physicochemical and Electrochemical Studies on Steel in Petroleum Industries

“…Impedance tests reveal details regarding the properties of the inhibition process, surface resistance, capacitance, and a substance’s capacity to prevent corrosion. Deviations from completely circular forms are attributed to frequency dispersion of interfacial impedance, which is associated with non-homogeneity of the surface and metal roughness. − A pattern emerged from our investigation, although it was not a whole semicircle. This could be because there is an inhibitor completely deflecting focus away from the semicircle.…”

“…A fresh oxide layer then develops within the solution, causing the potential to change towards a noble direction until a steady-state potential is attained. The cathodic process is reduced when inhibitor molecules are added to the aggressive medium, which causes a negative shift in the OCP. − …”

“…Charge-transfer resistance, denoted as R ct in the impedance data of the Nyquist plots, was used to compute the inhibitory efficiency as follows − …”

Novel Biologically Active N-Substituted Benzimidazole Derived Schiff Bases: Design, Synthesis, and Biological Evaluation

“…Reduction of the nitro group was confirmed within the singlet related to the protons from the amino group (4.44 to 5.25 ppm). The formation of the benzimidazole ring was confirmed by the disappearance of signals for the amino groups in 1,2-diamino-substituted benzenes 9-16, as well as the appearance of a singlet related to the proton of the amino group placed at position 2 on the benzimidazole nuclei (17)(18)(19)(20)(21)(22)(23)(24), which was downshifted in comparison with the singlet of the amino group in the diamino-substituted benzenes 9-16. The synthesis of targeted Schiff bases 28-45 was established by the observation of a singlet related to the proton of the imino group at 7.98-9.67 ppm in the proton spectra, as well as a signal for the C atom of the imino group in the carbon spectra.…”

“…Schiff bases can be easily synthesized by a condensation reaction of different amino substituted compounds with versatile aldehydes or ketones [7]. Besides the fact that Schiff bases are important building blocks in medicinal chemistry due to their broad spectrum of biological activity [8][9][10][11][12], they have also been used in coordination chemistry [13][14][15], in analytical chemistry [16], as dyes [17], as optical chemosensors [18][19][20], as polymers [21], in catalysis [22], in metallurgy and refining of metals, and as fungicidal and agrochemical compounds. Additionally, the interest of numerous scientists is focused on evaluating Schiff bases as ligands for transition metals displaying diverse biological activities, such as anticancer [23,24], antimicrobial [25,26], and antifungal activities [27].…”