Novel porphyrin derivatives as corrosion inhibitors for stainless steel 304 in acidic environment: synthesis, electrochemical and quantum calculation studies

Abstract

A Novel 5,10,15,20-tetra (thiophen-2-yl) porphyrin (P1) and 5,10,15,20-tetrakis (5-Bromothiophen-2-yl) porphyrin (P2) were successfully synthesized, and their chemical structures were proved based on its correct elemental analysis and spectral data (IR and 1H-NMR). These compounds were examined as corrosion inhibitors for stainless steel 304 (SS304) in 2 M HCl utilizing mass reduction (MR) and electrochemical tests at inhibitor concentration (1 × 10–6–21 × 10–6 M). The protection efficiency (IE %) was effectively enhanced with improving the concentration of investigated compounds and reached 92.5%, 88.5% at 21 × 10–6 M for P1 & P2, respectively and decreases with raising the temperature. Langmuir's isotherm was constrained as the best fitted isotherm depicts the physical–chemical adsorption capabilities of P1 & P2 on SS304 surface with change in ΔGoads = 22.5 kJ mol−1. According to the PDP data reported, P1 and P2 work as mixed find inhibitors to suppress both cathodic and anodic processes. Porphyrin derivatives (P1 & P2) are included on the surface of SS304, according to surface morphology techniques SEM/EDX and AFM. Quantum calculations (DFT) and Monte Carlo simulation (MC) showed the impact of the chemical structure of porphyrin derivatives on their IE %.

Eco-Friendly Piper cubeba Official Extract Corrosion Inhibition of C-Steel in 1 M Sulfamic Acid

“…As the dosage of the corrosion inhibitor is increased, i corr significantly drops and reaches a minimum of 25.8 μA cm –2 . These results validate the examined extract’s excellent inhibition and film-forming capacity . The addition of P.cubebaOE to the 1 M H 2 NSO 3 H solution does not change the hydrogen evolution mechanism or the reduction of H + ions at the C-steel surface, which mostly occurs through a charge-transfer mechanism, − based on the parallel cathodic Tafel lines.…”

“…These results validate the examined extract’s excellent inhibition and film-forming capacity. 27 The addition of P.cubebaOE to the 1 M H 2 NSO 3 H solution does not change the hydrogen evolution mechanism or the reduction of H + ions at the C-steel surface, which mostly occurs through a charge-transfer mechanism, 55 − 57 based on the parallel cathodic Tafel lines. Depending on whether the inhibitor causes a shift in corrosion-free potential E corr that is larger than 85 mV of SCE in either direction after being added, the inhibitor can be classified as either cathodic or anodic.…”

“…IE % and (θ) were calculated using the polarization curves (eqs and ) IE 0.25em % = 1 − i c o r r i corr normalo θ = IE % / 100 where the current corrosion densities of chemicals are represented by the variables i corr o and i corr , respectively. The polarization resistance ( R p ) of the test specimens in the 1 M H 2 NSO 3 H solution was calculated using the Stern–Geary eq below, taking into account the presence or absence of P.cubebaOE inhibitor R p = β a β c / 2.303 0.25em i corr ( β a + β c ) …”

“…The polarization resistance ( R p ) of the test specimens in the 1 M H 2 NSO 3 H solution was calculated using the Stern–Geary eq 7 below, taking into account the presence or absence of P.cubebaOE inhibitor. 27 …”

“…Utilizing natural resources will enable the achievement of both economic and environmental objectives. In several researches, plant extracts have been mentioned as prospective agents to lessen corrosion in different industrial solutions. − As reported previously, the ethanolic extract of (P.cubebaOE) contains levels of Yatein, Cbenin, cubebinone, cubebininolide, Hinokinin and cubebinin, single aldehyde, and α, β-unsaturated ketone. From the Piper cubeba, several phenolic acids and flavonoids have been found and extracted.…”